Wow... Your communication is top notch, I never had to go back to listen once again. Precise, simple yet detailed and easy to follow along for anyone who watches your videos... Thanks for your work!!!
The nostalgia factor is huge when it comes to meters if you're over a certain age. And if you are - nothing will trigger those feelings like yellow meters... Love it. Thanks.
I'm so glad to see you mention ABX testing. It's sad that the majority of audio reviewers don't do ABX tests. "Confimation Bias" is real and so easy to fall into. I've done it myself. I currently use a homemade amp switcher using a pair of Omron bifurcated relays. It uses the 12v trigger from my DAC to switch between my AVR amp and stereo amp. I am going to check out this Fosi switch (using your link of course).
A vast majority of audio reviewers are utterly useless & mainly engage in shilling product - gullible/uneducated & "marinated in bad sound" viewers feed this circle of confusion - Erin's uniquely measured appraisals are a tectonic shift in the right direction ;-)
Edit: I see someone else replied with the same thing so I'll copy/paste my reply here: It's been a while so help me out here... was it me saying to take the impedance of the speaker and calculate power based on that? If so, my rationale is that there's no way to calibrate this unless it's for a static load. So, what you're doing here is calibrating it for the Re of the speaker at Fs. That's the point where power is consumed the most. I don't know of an easier way for the modern consumer to "calibrate" this thing unless they used a static load which most aren't goin to run out and buy. I agree it's not ideal but I don't think it's so far from reasonable that it should be called "wildly inaccurate". You're not actually measuring the entire impedance; you'd need something like the Dayton DATS or a painstaking process of playing different tones and calculating the resistance over a lot of frequencies (I used to do this before the advent of the Woofer Tester / DATS). If this is one of those "gotcha" moments then trust me, it's not that. There's just no way for someone to measure the entire bandwidth of a speaker and calibrate this for that. You have to assume some static resistance and you can get that at Re/Fs using a DMM which most have around. Alternatively, they can sweep the impedance with a DATS and then find the frequency for which they want to calibrate. I actually have a video on the Dayton DATS. Hope that helps.
@@ErinsAudioCorner Sorry but you're wrong again. I'm the OP (PHD). See my last comment (#12) in the original thread. Now, I admit, I'm no audio expert. but I do have some basic electricity knowledge and a PhD in that subject... ;-)
you’re the OP of what? I’m confused as to what that means. Sorry, I still disagree with you. Context is everything. As for your PHD, congratulations. Hopefully you’re doing what you love with it.
@@ErinsAudioCorner OP = original poster of the AVS thread regarding your attemp to measure the spk impedance (PHD is my user name at ASR). Can you tell the nominal power of an electric AC motor just by measuring the DC resistance of its stator coil? Of course not because an ideal AC motor would have 0 DC resistance and still be capable of generating MW of real power. Power in electromagnetic-based electromechanical transducers like loudspeakers and AC motors, is generated by the product of the drawn current and the induced back electromotive force (EMF as in voltage). The only way to assess the equivalent resistance of the active power drawn is to apply voltage and, measure the current while power is generated. You did nothing nut measured static DC resistance of the spk which has 0 correlation to nominal spk impedance.
I can't lie, i love meters too. Don't care if they don't really do anything, adds fun visuals and some feedback. Adding some functionality as a speaker selector is smart idea.
No one else does content like this. Thank you! You answered a question that I always had wondered, do things like this affect the output in any way. I'd guess that adding this in the signal path increases resistance thus decreasing output due to insertion losses and increased signal path. Another cool test would be to test the nominal resistance on the back side of the meter while it is connected to the speaker vs the speaker itself!
They have a winner with this one. Of course, speaker selector switches are common but amplifier selection switchers are not. I could have used this many times in the past. Plus, like you said, it looks cool, too. 😊
In amazon and aliexpress reviews the main complaint on the fosi LC30 is about the VU meters hardly moving, right now it only has a 3.1 stars rating. In audiokarma there is a thread talking about this model and the common complaint also seems to be about the VU meters hardly moving even with the highest sensitivity used. Someone in that thread asked to fosi in a email about this problem and they responded that they adressed the sensitivity issue in the latest batch of units. It would be nice if you can also ask them about that problem to see it they are effectively solving that issue
@@ErinsAudioCorner Perhaps your unit is from the latest batch? It would be good if Fosi could provide some clarification as this seems like a general issue with this model at this time.
It was me who communicated with Fosi about the VU meters not being sensitive enough. Fosi wanted to send me a replacement Front display board but I didn’t want to open unit up to replace it myself so I returned it to Amazon. It’s a great little unit except for the VU meters not having enough gain. If they do a version 2 I would purchase again. And I agree it does have a small load when connected. I thought it was just me but this review confirms it. Nice review 😊
@@DavidBurns-sq4kd It's not actually a load. It's more like contact resistance in the connectors, relays, and pcb materials. From Erin's measurements I would assess it as about 0.1 Ohms... which isn't exactly disastrous.
I have a Marantz sr6015 with 2 memories of EQ, and i use this display to change my stereo linton speakers for music to my polk lsims to home theater. Thanks by your great job
I use the receiver with an advance paris power amp that have vu, i can visual sync them with the wheel. VU seems fine to me, if you give enough sensibility.
Looking forward to the v3 mono review. I think it makes more sense to have two separate 48V 5A power supplies rather than the split 10A power supply though. You may already know this but some reviewers had noise issues with the split power supply.
Had 3 of the similar Douk Audio VU3 speaker/amp switcher + VU meter and every single one of them failed eventually < 1 year on completely different setups despite being gently used (and rarely plugged/unplugged). Typically one of the input or output channels stops working rendering it useless. The Fosi may be of higher quality, but given very comparable pricing, I suspect the internals are very much the same. I also tried daisy chaining two of these and the noise levels increased very significantly.
Thanks for the video and review. Very helpful. I just bought the unit with black meters. Looking forward to the meters in action and A/B switching between speakers.
Have the Douk version (because the other can be hard to find at time). A cool toy. Gives your average joe an excuse to have 2 sets of speakers and/or 2 amps.
ok, the Fosi has a much nicer remote. (and looks a tiny bit nicer overall). For what it is, they work great. Switching between amps is easy, with setting levels, never thought about speakers.
I have investigated some of these low cost solutions in the past and they are not always true logarithmic indicators. A true reading power meter is useful in insuring you are not destroying your hearing as really other than SPL it’s the only indicator that your music is too loud. Handy if you have tinnitus or even better if you want to prevent it. Clean sound is so pleasing you just want to keep turning it up and up and up.
Here's the fun part... the actual meter movements, themselves, are linear to voltage. That is if you apply twice as much voltage the needle reliably moves twice as far. The non-linearities most people suggest are not in the meter movement... they are in the scales drawn on the face of the meters.
Good review. Following the Amazon link, I see LC30 owner satisfaction is not great. The most common complaint is that you cannot adjust the meter sensitivity high enough so that you see the needles bounce a lot at normal listening levels. This makes sense, as most home listening does not use a lot of watts. Is this an issue if you just want to see the meters bounce, or were these owners using it wrong?
I’m not sure why others are having that complaint. Unless they are truly running more than the 300w these meters show. For most folks, though, I’d imagine they don’t have a realistic sense of how much power is actually being put out.
I read those reviews and went for a Neohippo ET30. No issues with sensitivity and you can change the colour of the screen, couldn't quite get a McIntosh blue though, more a bluey green. There's a review of it on Audio Science Review.
@@middleearthltd I watched it all, I understand you can adjust the sensitivity to be accurate at a given load. That is not what these unhappy meter buyers are complaining about. They want to see the meters move a lot. Manufacturers understood this back in the day. Most amps with integral meters had two sensitivity reading printed on the face. One maxed out at 300 watts like the Fosi, and another that maxed at say 10 watts. A front panel switch let you choose between the two. So, everyone could enjoy the bouncy meters all the time. It reflected that scales should reflect what their owners want to experience. It looks like Fosi is getting many Amazon down votes and returns because some people buy meters just to see them bounce. I bet they add the 2nd scale to v2.
Thanks for the explanation on how to do the calibration and the discussion about ABX testing. That said 😅, based on the thumbnail/title I was hoping for more of you having a bit of fun with the meter and less time in this 'review' discussing the separate ABX device and the shortcomings of AB switching (e.g. really enjoyed how you spent time talking subjectively about the Blades in addition to the objective stuff). Thanks for all that you do, Erin. I'm learning so much. 👍
1. Does Audiophile Reviewers use speaker/amp selector? 2. Does it effect imaging? 3. What would be better/best audiophile grade product (any company) for speaker/amp selector?
I was thinking of some device which would allow me to have AVR and some good stereo amp connected and just switch the speakers between amps, this seems to be able to do it? Albeit VU are not required for me personally.
@@Douglas_Blake_579 I've seen that, not sure how it works, but I doubt my Denon X3700 has it. I thought about something like Cambridge Audio EVO 150 or similar, I like Denon sound for HT, but for music Heos is not my friend and the amp section while being OK, is no match for anything like Evo.
@@ChrisCiapala Basically it's done by providing pre-amp outputs for the Front L R speaker pair so you can use your own amplifier/dsp/ whatever. Check your user manuals, they might explain it better.
DC resistance is not the same as AC impedance of the load. Also the Voltage measured on your DMM is in RMS and the display of your power meters is in VPP. I mean close enough for horseshoes I guess but let's acknowledge that the meters are for fun not for real measurements
The calibration of the meter between wattage level and db's is not correct. The meter scale shows 100 watts coinciding with 0 db, plus 2 watts coinciding with minus 20 db. 2 watts is 1/50th of 100 watts, & 20 log 1/50 = minus 34 db not minus 20 db. So worth bearing in mind.😊
Erin, I am surprised. Your method for determining impedance and then power is so wrong. I know you said it wasn't accurate, but it is so wildly inaccurate. I know you know better than this. Like your channel, but you should have just left that part out or linked to some more accurate info on the subject.
Edit: I see someone else replied with the same thing so I'll copy/paste my reply here: It's been a while so help me out here... was it me saying to take the impedance of the speaker and calculate power based on that? If so, my rationale is that there's no way to calibrate this unless it's for a static load. So, what you're doing here is calibrating it for the Re of the speaker at Fs. That's the point where power is consumed the most. I don't know of an easier way for the modern consumer to "calibrate" this thing unless they used a static load which most aren't goin to run out and buy. I agree it's not ideal but I don't think it's so far from reasonable that it should be called "wildly inaccurate". You're not actually measuring the entire impedance; you'd need something like the Dayton DATS or a painstaking process of playing different tones and calculating the resistance over a lot of frequencies (I used to do this before the advent of the Woofer Tester / DATS). If this is one of those "gotcha" moments then trust me, it's not that. There's just no way for someone to measure the entire bandwidth of a speaker and calibrate this for that. You have to assume some static resistance and you can get that at Re/Fs using a DMM which most have around. Alternatively, they can sweep the impedance with a DATS and then find the frequency for which they want to calibrate. I actually have a video on the Dayton DATS. Hope that helps.
@@ErinsAudioCorner Using nominal rated impedance if known would be better. Multiplying DC resistance by 1.25 to 1.5 would be a step in the right direction. Loudspeakers can sometimes have impedance as low as the woofer DC resistance, but commonly measure somewhat higher.
I have looked at this one, but so many bad amazon reviews for low meter sensitivity. Do you have any reason why that might be? How much actual Watts do you need to hit full scale at the highest sensitivity? I have the Douk Audio VU3 , have no issues with it. I also am looking at the Neohipo ET30, it gets much better reviews.
I got one off the Fosi Kickstarter Campaign Mine has black meters which I prefer I ambivalent about it but if you use a couple Fosi amplifiers it would look cool with them sitting on top. I could be wrong but as I recall it is rated for 150 watts Regardless it is a gadget and I like Kickstarter Campaigns After my alien abduction I pucker-up when probe usage is discussed like this
I too crave a meter on my system. Thanks for this review. Does this meter measure the current in the load? I was wondering if the power loss is due to a sense resistor. And related, is it possible to hang this on the output of the amp in parallel with the speaker, without running the speaker signal through it.
Thanks. One thing I am not clear on is if the unit changes the impedance on the amp? I have an older tube amp where the speakers are hooked up to taps marked 4, 8 and 16. If I am running 8-ohm speakers on the tap marked eight would this stay the same with the LC30 installed? Thanks again!
Bought one of these following your excellent review, but upon calibration found it to be wildly inaccurate! When I calibrated it (using Ohm’s law and an expensive Fluke multimeter) at low power it was off by over 50% in the higher range and when I calibrated it at high power it was off by over 50% in the low range. Calibration at mid power left both low and high power quite inaccurate. Trying to return it for refund but it seems they might just be ghosting me.
One thing to mention is some multimeters are only accurate up to around 400hz or so so if you're using a 1 khz tone you might not be getting an accurate reading.
Erin ... when you review the V3Mono amps, spend some time watching the temperature... and listen for output coil saturation while on a dummy load (the coils will "sing", it's clearly audible).
@@ErinsAudioCorner Coil saturation is a disaster for these amplifiers. It detunes the low pass filter and adds distortion to the outputs. Indeed it is a bit scary when you can follow the lyrics by listening to the filters. I have a couple of pro TPA3255 boards here with nice beefy coils, using heavy gauge wire, that do not saturate and the difference is clearly audible.
@@Harrisongrey19 Did you mean PFFB ... Post Filter Feed Back? That won't fix a coil that can't handle the full current output of an amplifier. These new smaller coils they're using are generally only rated for 4 or 5 amps... in a circuit that can produce 17 amp peaks. The magnetic field around the wires, saturates the ferrite core and results in a loss of inductivity which can result in detuning the output filter. PFFB no matter how well implemented can't change that. The only answers are to use better coils or limit the output to less than the rating of the coils.
I was talking to a salesman in a HiFi shop about cables and if you can truly hear an audible difference. The salesman said he gave some expensive cables to a client who is an electrical engineer to try out for comparison. The engineer ran some tests on the expensive cables and they measured exactly the same as his cheaper ones. Despite what the data showed, the engineer claimed to hear a noticeable improvement in sound quality when using the expensive cables, yet he couldn’t explain why he could hear a difference. While I’m skeptical that things such as expensive cables and exotic crossover parts will make a noticeable improvement in sound quality, it does make for potentially interesting comparison tests when you have the ability to level match and switch between different components.
Claims are not scientific, they are perceptions and opinions, or simply lies to promote the sale of snake oil. Any expectation that expensive cables will make a noticeable improvement in sound quality has to be tested. Expect blind listening tests to return statistical results of 50:50 and then you will know for sure.
I have 2 pairs of speakers. 1 pair driven by a pair of monoblocks. The other by a stereo power amp. Both connected to the same preamp. I can choose to have either or both sets running. Instant, seamless comparison. Of course, it’s not done blind. I always know which set up I’m listening to and there is no easy of volume matching. But it does allow me to choose the combination that best suits the genre I’ve selected.
@@Douglas_Blake_579 Yeah but I've got a phono pre, a cd player and stand alone dac and subs and that makes for lots of boxes, power supplies and cables and all that makes me want to go back to an all in one and a pair of speakers ☺️
I just realized an amp switcher would be pretty good for when I'm using the computer on the other end of my room, to use the rear speakers as stereo "front" speakers.
I grew up watching the meters on my dad's Marantz Model 500 and 510M amps, and the scope on his Marantz 150 tuner. I could spend hours sitting in front of the stereo just watching those move around.
If you don't have a meter that can reliably read 1khz AC sine waves, use a 60hz hz wave. That's not my main issue. This meter is neat, but as soon as you're not at 1khz, the meter will read wrong. I would suggest you measure the speaker, do this setup at the lowest impedance at the lowest frequency. At least then, you know when it's pulling the most power, which I think is way more neat than 1khz.
I initially calibrated the meters using my measurement hardware. I got the same voltage out reading as I did with the multimeter I showed. But yes, I’ve been told that some multimeters aren’t reliable at anything other than 60 Hz.
@@ErinsAudioCorner Look for "True RMS" in the multimeter's specs. Most are pretty accurate up to about 400 hz. Also the meters themselves are DC devices and do require some filtering to read accurately. So it's unlikely they can respond to anything over about 1 or 2 hz to begin with. Calibrating at 100hz should be more than good enough.
I'm sure someone could DIY scan the output displays and make blue or white and change the lights. If they have access to a quality graphic printer thing. Or make your own with funny labels.
If you want to keep your Multimeter, switch it to AC volts *before* you connect it to your speaker leads. Also note that the LC30 has very low sensitivity and will not properly display lower power levels. There are better and less expensive alternatives out there.
@@dougbulldog9947 You know we can't post links in these comments.... right? Go to your favourite online vendor and search for "audio power meters" or "speaker switcher" and such... The best "budget" version I've seen is the one from Douk Audio.
As many have posted, true blind test aren’t really done in this industry. I’m talking about having an assistant set up the gear and you walk in blindfolded and sit down. No looking at the gear beforehand no idea what gear it is.
I would love to see Danny at GR subjected to some true ABX testing of his "audiophile power cords", stuff like elevating the speaker wires off the ground, and other esoteric industry nonsense. I'm sure he'd just move the goal posts though when the results didn't match his preconceived bias. 🙄🙄
I love to see him end up picking the speakers that 1. Have no no res 2. Don't have his fancy tube connectors 3. Have no fancy capacitors or crossover. That would pretty much put him out of business, rendereing all his "improvements" bogus!!! These guys will never subject themselves to ABX testing because they know the stakes are too high if they fail the test, and they know they'll fail the test.
@@dlloyd6300 Its that Jay guy. Back when Danny called out reviewers, him and several others came to Texas to put him to the test. Looked liked they had a good time. Probably a year and a half ago or so.
When I first saw LC30 I thought you might be reviewing the bigger brother of my LC15 guitar amp... I like Laney amps, but I don't think it'd look very hifi if you measured it on the Kippel :D
@@ErinsAudioCorner Try them with "background level" listening (half a watt or so). Even with the knob all the way up the needles barely get off the left side.
The problem with audio signal is that current and voltage are not necessarily in phase. Therefore a wattage meter does not show "dead current" Nice gimmick nonetheless.
I cannot see this thing being useful for identifying differences between equipment or cables. Putting a cheap box made with cheap parts in the chain will degrade a highly resolving system and smooth over differences. I guess that is good for flat earthers who like to imagine there are no differences between cables, DACs, etc.
A person who provides scientific evidence of a expensive cable not providing a difference in audio quality from a average quality cable is a flat earther?
CLIP INDICATOR? Would love to have one of these switch manufacturers include a LED clipping indicator. The circuit is fairly simple, so perhaps adding it wouldn't add a lot to the cost. Many tweeters are fried by an moderately-powered amp clipping. If you think this idea has merit @ErinsAudioCorner, please pass it along to Fosi.
Clipping indicators, to be meaningful, have to be calibrated to an amplifier's output using an oscilloscope. They should start to show at about 90% of max output. You're not going to do that in a simple passive meter. I've been over the need for Clipping and Over Temperature warnings with Fosi. I even provided documentation to show how to add it to their TPA3255 designs. The chip natively supports it, it's just a matter of implementation. And yes, if they would include this on their amplifier designs, many tweeters would thank them.
@@Douglas_Blake_579 There is a more general way to accomplish this without having to calibrate to each amplifier. Normal audio signals, unless clipped, are NEVER flat at the top and/or bottom of their waveform (which is what you see on the oscilloscope when an amp is clipped). An op amp circuit designed to sense an even-momentary DC (flat) signal could drive/trigger an LED. It would not matter if the amp was outputting DC signal at 50 watts or 500 watts. No it is not a perfect design, but it does overcome the need for calibration. The main variable in the circuit design would be how long a DC duration would have to be present to trigger the indicator. I'd guess 6 milliseconds for starters. (And of course, no signal (0 vollts DC) would have to be ignored.) There is another more complicated way, but it would involve an analog to digital conversion.
@@michaelsparrow4798 What you are proposing is a "Peak" indicator... that's something else entirely. To drive the meters a small bit of the speaker signal is captured and stored, usually with a simple diode and capacitor circuit. Without too much trouble a comparator can be used to monitor that as an "average level" and fire an LED if the average is exceeded by some arbitrary amount. That is more or less what the other guys are doing in their meters. It's not a true clipping indicator since, if the average is running at a watt or so, a 5 watt totally unclipped peak can trigger the indicator. It looks cool, but it's actually pretty useless in protecting tweeters. A secondary flaw in such a circuit is that if the average is running well into clipping, the peak indicator may never be triggered because the flat topping you pointed out doesn't exceed the comparator threshold. This is why I've been pressing these Chi-amp makers to take advantage of the TPA3255's internal analytics and external CLIP/OTW (pin 21) and FAULT (pin 19) signals to provide amplifier front panel warning lights. In fact I have a couple of DIY versions of this on my own website. I can't post a link here or the whole comment vanishes... but Erin could, if he's willing.
@@Douglas_Blake_579 I've found that the workaround to not being able to include a URL in comments, is to specify which terms to enter into a search engine box that will result in the desired site coming up in the top 3. I'm interested.
@@Douglas_Blake_579 @ErinsAudioCorner Hey Erin. Please consider helping post this fellow's URL. Based on what he's commented, he knows of what he speaks.
Hi Erin, love your channel and all the pertanent intel you share with us. I trust your knowledge and appreciate how you explain hifi science in such a fashion that even a complete rookies like myself can actually grasp the message. I need to get some funds to you because I purchased some speakers but forgot to include your affiliate link. Are you on Facebook so I could privately message you?
Wow... Your communication is top notch, I never had to go back to listen once again. Precise, simple yet detailed and easy to follow along for anyone who watches your videos... Thanks for your work!!!
Good stuff Erin, a smart and realistic way to incorporate some of the “fun” in the space.
The nostalgia factor is huge when it comes to meters if you're over a certain age. And if you are - nothing will trigger those feelings like yellow meters... Love it. Thanks.
I'm so glad to see you mention ABX testing. It's sad that the majority of audio reviewers don't do ABX tests. "Confimation Bias" is real and so easy to fall into. I've done it myself. I currently use a homemade amp switcher using a pair of Omron bifurcated relays. It uses the 12v trigger from my DAC to switch between my AVR amp and stereo amp. I am going to check out this Fosi switch (using your link of course).
Yep. I use it for my amplifier reviews and speaker listening.
Agreed!
With ABX you cannot analyze, check for listening fatigue. For short time comparison, it is OK.
A vast majority of audio reviewers are utterly useless & mainly engage in shilling product - gullible/uneducated & "marinated in bad sound" viewers feed this circle of confusion - Erin's uniquely measured appraisals are a tectonic shift in the right direction ;-)
I so want one of these. Also, thank you for you channel. I am learning a LOT about speakers and audio.
Hey, thanks for that!
These blind tests are "Audiophiles" worst nightmare.
Not for this audiophile! I love ScIeNcE 🧪🔭 😊
And a consumers dream!
Only for the ones who refuse to learn...
Probably because everthing in the signal chain has its sound characteristic.
@@bartbarelds8454
More likely because it will show they don't.
Agreed, ... meters are the best.
Nailing the aesthetic of meter visuals bouncing to the signal, is an artform unto itself.
Google "Measuring speaker's impedance using a DMM? - Is Erin serious, or am I missing something?"
Edit: I see someone else replied with the same thing so I'll copy/paste my reply here:
It's been a while so help me out here... was it me saying to take the impedance of the speaker and calculate power based on that? If so, my rationale is that there's no way to calibrate this unless it's for a static load. So, what you're doing here is calibrating it for the Re of the speaker at Fs. That's the point where power is consumed the most. I don't know of an easier way for the modern consumer to "calibrate" this thing unless they used a static load which most aren't goin to run out and buy. I agree it's not ideal but I don't think it's so far from reasonable that it should be called "wildly inaccurate".
You're not actually measuring the entire impedance; you'd need something like the Dayton DATS or a painstaking process of playing different tones and calculating the resistance over a lot of frequencies (I used to do this before the advent of the Woofer Tester / DATS). If this is one of those "gotcha" moments then trust me, it's not that. There's just no way for someone to measure the entire bandwidth of a speaker and calibrate this for that. You have to assume some static resistance and you can get that at Re/Fs using a DMM which most have around. Alternatively, they can sweep the impedance with a DATS and then find the frequency for which they want to calibrate. I actually have a video on the Dayton DATS. Hope that helps.
@@ErinsAudioCorner
Sorry but you're wrong again. I'm the OP (PHD). See my last comment (#12) in the original thread.
Now, I admit, I'm no audio expert. but I do have some basic electricity knowledge and a PhD in that subject... ;-)
you’re the OP of what? I’m confused as to what that means.
Sorry, I still disagree with you. Context is everything.
As for your PHD, congratulations. Hopefully you’re doing what you love with it.
@@ErinsAudioCorner
OP = original poster of the AVS thread regarding your attemp to measure the spk impedance (PHD is my user name at ASR).
Can you tell the nominal power of an electric AC motor just by measuring the DC resistance of its stator coil?
Of course not because an ideal AC motor would have 0 DC resistance and still be capable of generating MW of real power.
Power in electromagnetic-based electromechanical transducers like loudspeakers and AC motors, is generated by the product of the drawn current and the induced back electromotive force (EMF as in voltage).
The only way to assess the equivalent resistance of the active power drawn is to apply voltage and, measure the current while power is generated.
You did nothing nut measured static DC resistance of the spk which has 0 correlation to nominal spk impedance.
I can't lie, i love meters too. Don't care if they don't really do anything, adds fun visuals and some feedback. Adding some functionality as a speaker selector is smart idea.
No one else does content like this. Thank you! You answered a question that I always had wondered, do things like this affect the output in any way. I'd guess that adding this in the signal path increases resistance thus decreasing output due to insertion losses and increased signal path. Another cool test would be to test the nominal resistance on the back side of the meter while it is connected to the speaker vs the speaker itself!
Good idea! Don’t know why I didn’t think of doing that myself.
Hands down the best review of this product by a mile. Hell by a hundred miles. Thank you and appreciate you.
Thank you ever so much for your time and work Erin,, 👍😎👍
Great video! Thanks for the info on how to quickly calibrate the meters!!
I love meters too, adds a feeling of zen when listening somehow.
I always enjoy your reviews, and this was well done.Thanks!
Awesome, thank you!
They have a winner with this one. Of course, speaker selector switches are common but amplifier selection switchers are not. I could have used this many times in the past. Plus, like you said, it looks cool, too. 😊
In amazon and aliexpress reviews the main complaint on the fosi LC30 is about the VU meters hardly moving, right now it only has a 3.1 stars rating. In audiokarma there is a thread talking about this model and the common complaint also seems to be about the VU meters hardly moving even with the highest sensitivity used. Someone in that thread asked to fosi in a email about this problem and they responded that they adressed the sensitivity issue in the latest batch of units. It would be nice if you can also ask them about that problem to see it they are effectively solving that issue
When I had it set up in my living room I didn’t notice that issue. But I wasn’t specifically looking for it. 🤔
@@ErinsAudioCorner Perhaps your unit is from the latest batch? It would be good if Fosi could provide some clarification as this seems like a general issue with this model at this time.
It was me who communicated with Fosi about the VU meters not being sensitive enough. Fosi wanted to send me a replacement Front display board but I didn’t want to open unit up to replace it myself so I returned it to Amazon. It’s a great little unit except for the VU meters not having enough gain. If they do a version 2 I would purchase again. And I agree it does have a small load when connected. I thought it was just me but this review confirms it. Nice review 😊
@@DavidBurns-sq4kd
It's not actually a load. It's more like contact resistance in the connectors, relays, and pcb materials. From Erin's measurements I would assess it as about 0.1 Ohms... which isn't exactly disastrous.
@@DavidBurns-sq4kd Thanks for the explanation, good to know that fosi was trying to fix the problem of your unit
I have a Marantz sr6015 with 2 memories of EQ, and i use this display to change my stereo linton speakers for music to my polk lsims to home theater. Thanks by your great job
I use the receiver with an advance paris power amp that have vu, i can visual sync them with the wheel. VU seems fine to me, if you give enough sensibility.
Looking forward to the v3 mono review. I think it makes more sense to have two separate 48V 5A power supplies rather than the split 10A power supply though.
You may already know this but some reviewers had noise issues with the split power supply.
Had 3 of the similar Douk Audio VU3 speaker/amp switcher + VU meter and every single one of them failed eventually < 1 year on completely different setups despite being gently used (and rarely plugged/unplugged). Typically one of the input or output channels stops working rendering it useless. The Fosi may be of higher quality, but given very comparable pricing, I suspect the internals are very much the same. I also tried daisy chaining two of these and the noise levels increased very significantly.
Thanks for the video and review. Very helpful. I just bought the unit with black meters. Looking forward to the meters in action and A/B switching between speakers.
Have the Douk version (because the other can be hard to find at time). A cool toy. Gives your average joe an excuse to have 2 sets of speakers and/or 2 amps.
ok, the Fosi has a much nicer remote. (and looks a tiny bit nicer overall). For what it is, they work great. Switching between amps is easy, with setting levels, never thought about speakers.
Thank you Erin!
Passive preamps will let you level match. I bought a very nice one for about $60. Merely a high quality volume knob and nothing else.
I have investigated some of these low cost solutions in the past and they are not always true logarithmic indicators. A true reading power meter is useful in insuring you are not destroying your hearing as really other than SPL it’s the only indicator that your music is too loud. Handy if you have tinnitus or even better if you want to prevent it. Clean sound is so pleasing you just want to keep turning it up and up and up.
Here's the fun part... the actual meter movements, themselves, are linear to voltage. That is if you apply twice as much voltage the needle reliably moves twice as far. The non-linearities most people suggest are not in the meter movement... they are in the scales drawn on the face of the meters.
@@Douglas_Blake_579 True. The digital bar graph units are far worse.
Yes your information is top notch !!
Good review. Following the Amazon link, I see LC30 owner satisfaction is not great. The most common complaint is that you cannot adjust the meter sensitivity high enough so that you see the needles bounce a lot at normal listening levels. This makes sense, as most home listening does not use a lot of watts. Is this an issue if you just want to see the meters bounce, or were these owners using it wrong?
Did you watch the review….apparently not
Go to approximately the 11 minute mark
I’m not sure why others are having that complaint. Unless they are truly running more than the 300w these meters show.
For most folks, though, I’d imagine they don’t have a realistic sense of how much power is actually being put out.
I read those reviews and went for a Neohippo ET30. No issues with sensitivity and you can change the colour of the screen, couldn't quite get a McIntosh blue though, more a bluey green. There's a review of it on Audio Science Review.
@@middleearthltd I watched it all, I understand you can adjust the sensitivity to be accurate at a given load. That is not what these unhappy meter buyers are complaining about. They want to see the meters move a lot.
Manufacturers understood this back in the day. Most amps with integral meters had two sensitivity reading printed on the face. One maxed out at 300 watts like the Fosi, and another that maxed at say 10 watts. A front panel switch let you choose between the two. So, everyone could enjoy the bouncy meters all the time. It reflected that scales should reflect what their owners want to experience.
It looks like Fosi is getting many Amazon down votes and returns because some people buy meters just to see them bounce. I bet they add the 2nd scale to v2.
@@hackedoff736 Yep, I see you can adjust the meter range on that one.
Thanks for the explanation on how to do the calibration and the discussion about ABX testing. That said 😅, based on the thumbnail/title I was hoping for more of you having a bit of fun with the meter and less time in this 'review' discussing the separate ABX device and the shortcomings of AB switching (e.g. really enjoyed how you spent time talking subjectively about the Blades in addition to the objective stuff).
Thanks for all that you do, Erin. I'm learning so much. 👍
There’s really not a lot to say about something like this. It doesn’t do anything to the sound so it is what it is.
@@ErinsAudioCorner true. I guess I was just hoping for some 'bouncing meter' shots like something out of a 90s movie 😜
1. Does Audiophile Reviewers use speaker/amp selector?
2. Does it effect imaging?
3. What would be better/best audiophile grade product (any company) for speaker/amp selector?
Im also do Diy pi base DSMPlayer one with analog VU meter... So fun to see Vu work with digital steaming music.
Are you sure the needles move? So many reviews say they don't.
I was thinking of some device which would allow me to have AVR and some good stereo amp connected and just switch the speakers between amps, this seems to be able to do it? Albeit VU are not required for me personally.
Sounds like something like this is what you’re looking for.
Many AVRs natively support this as a bypass channel for the front left and right speakers.
@@Douglas_Blake_579 I've seen that, not sure how it works, but I doubt my Denon X3700 has it. I thought about something like Cambridge Audio EVO 150 or similar, I like Denon sound for HT, but for music Heos is not my friend and the amp section while being OK, is no match for anything like Evo.
@@ChrisCiapala
Basically it's done by providing pre-amp outputs for the Front L R speaker pair so you can use your own amplifier/dsp/ whatever. Check your user manuals, they might explain it better.
DC resistance is not the same as AC impedance of the load. Also the Voltage measured on your DMM is in RMS and the display of your power meters is in VPP. I mean close enough for horseshoes I guess but let's acknowledge that the meters are for fun not for real measurements
I love those meters. Fantastic.
A very informative video, thank you! Some have complained meter sensitivity is weak compared to DOUK Audio One Little Bear. Is that true?
The calibration of the meter between wattage level and db's is not correct.
The meter scale shows 100 watts coinciding with 0 db, plus 2 watts coinciding with minus 20 db.
2 watts is 1/50th of 100 watts, & 20 log 1/50 = minus 34 db not minus 20 db.
So worth bearing in mind.😊
Erin, I am surprised. Your method for determining impedance and then power is so wrong. I know you said it wasn't accurate, but it is so wildly inaccurate. I know you know better than this. Like your channel, but you should have just left that part out or linked to some more accurate info on the subject.
Edit: I see someone else replied with the same thing so I'll copy/paste my reply here:
It's been a while so help me out here... was it me saying to take the impedance of the speaker and calculate power based on that? If so, my rationale is that there's no way to calibrate this unless it's for a static load. So, what you're doing here is calibrating it for the Re of the speaker at Fs. That's the point where power is consumed the most. I don't know of an easier way for the modern consumer to "calibrate" this thing unless they used a static load which most aren't goin to run out and buy. I agree it's not ideal but I don't think it's so far from reasonable that it should be called "wildly inaccurate".
You're not actually measuring the entire impedance; you'd need something like the Dayton DATS or a painstaking process of playing different tones and calculating the resistance over a lot of frequencies (I used to do this before the advent of the Woofer Tester / DATS). If this is one of those "gotcha" moments then trust me, it's not that. There's just no way for someone to measure the entire bandwidth of a speaker and calibrate this for that. You have to assume some static resistance and you can get that at Re/Fs using a DMM which most have around. Alternatively, they can sweep the impedance with a DATS and then find the frequency for which they want to calibrate. I actually have a video on the Dayton DATS. Hope that helps.
@@ErinsAudioCorner Using nominal rated impedance if known would be better. Multiplying DC resistance by 1.25 to 1.5 would be a step in the right direction. Loudspeakers can sometimes have impedance as low as the woofer DC resistance, but commonly measure somewhat higher.
First review of the LC30 that shows the measures we were waiting. Do this affect the signal ? Not audible :) Thanks Erin
I have looked at this one, but so many bad amazon reviews for low meter sensitivity. Do you have any reason why that might be? How much actual Watts do you need to hit full scale at the highest sensitivity? I have the Douk Audio VU3 , have no issues with it. I also am looking at the Neohipo ET30, it gets much better reviews.
I got one off the Fosi Kickstarter Campaign
Mine has black meters which I prefer
I ambivalent about it but if you use a couple Fosi amplifiers it would look cool with them sitting on top.
I could be wrong but as I recall it is rated for 150 watts
Regardless it is a gadget and I like Kickstarter Campaigns
After my alien abduction I pucker-up when probe usage is discussed like this
I too crave a meter on my system. Thanks for this review. Does this meter measure the current in the load? I was wondering if the power loss is due to a sense resistor. And related, is it possible to hang this on the output of the amp in parallel with the speaker, without running the speaker signal through it.
Thanks. One thing I am not clear on is if the unit changes the impedance on the amp? I have an older tube amp where the speakers are hooked up to taps marked 4, 8 and 16. If I am running 8-ohm speakers on the tap marked eight would this stay the same with the LC30 installed? Thanks again!
It does not.
@@ErinsAudioCorner Thanks!
Bought one of these following your excellent review, but upon calibration found it to be wildly inaccurate! When I calibrated it (using Ohm’s law and an expensive Fluke multimeter) at low power it was off by over 50% in the higher range and when I calibrated it at high power it was off by over 50% in the low range. Calibration at mid power left both low and high power quite inaccurate. Trying to return it for refund but it seems they might just be ghosting me.
One thing to mention is some multimeters are only accurate up to around 400hz or so so if you're using a 1 khz tone you might not be getting an accurate reading.
Erin ... when you review the V3Mono amps, spend some time watching the temperature... and listen for output coil saturation while on a dummy load (the coils will "sing", it's clearly audible).
That’s always a scary thing. Especially noticeable with multitone!!
@@ErinsAudioCorner
Coil saturation is a disaster for these amplifiers. It detunes the low pass filter and adds distortion to the outputs.
Indeed it is a bit scary when you can follow the lyrics by listening to the filters.
I have a couple of pro TPA3255 boards here with nice beefy coils, using heavy gauge wire, that do not saturate and the difference is clearly audible.
@@Douglas_Blake_579FFB
@@Harrisongrey19
Did you mean PFFB ... Post Filter Feed Back?
That won't fix a coil that can't handle the full current output of an amplifier.
These new smaller coils they're using are generally only rated for 4 or 5 amps... in a circuit that can produce 17 amp peaks. The magnetic field around the wires, saturates the ferrite core and results in a loss of inductivity which can result in detuning the output filter.
PFFB no matter how well implemented can't change that. The only answers are to use better coils or limit the output to less than the rating of the coils.
@@Douglas_Blake_579 nope FFB “Fosi Fan Boy”
I was talking to a salesman in a HiFi shop about cables and if you can truly hear an audible difference. The salesman said he gave some expensive cables to a client who is an electrical engineer to try out for comparison. The engineer ran some tests on the expensive cables and they measured exactly the same as his cheaper ones. Despite what the data showed, the engineer claimed to hear a noticeable improvement in sound quality when using the expensive cables, yet he couldn’t explain why he could hear a difference. While I’m skeptical that things such as expensive cables and exotic crossover parts will make a noticeable improvement in sound quality, it does make for potentially interesting comparison tests when you have the ability to level match and switch between different components.
Claims are not scientific, they are perceptions and opinions, or simply lies to promote the sale of snake oil.
Any expectation that expensive cables will make a noticeable improvement in sound quality has to be tested.
Expect blind listening tests to return statistical results of 50:50 and then you will know for sure.
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I have 2 pairs of speakers. 1 pair driven by a pair of monoblocks. The other by a stereo power amp. Both connected to the same preamp. I can choose to have either or both sets running. Instant, seamless comparison. Of course, it’s not done blind. I always know which set up I’m listening to and there is no easy of volume matching. But it does allow me to choose the combination that best suits the genre I’ve selected.
I want do this but I have a vinyl rig and it's hurting my brain just thinking about how to go about connecting everything up
@@crazyprayingmantis5596
The meters plug into our speaker leads.
Amp to meter ... meter to speakers.
@@Douglas_Blake_579
Yeah but I've got a phono pre, a cd player and stand alone dac and subs and that makes for lots of boxes, power supplies and cables and all that makes me want to go back to an all in one and a pair of speakers ☺️
@@crazyprayingmantis5596
If you don't understand the wiring, I suggest that an all-in-one is probably a smart move.
Douk Audio makes one that looks JUST like it and I own one. I would bet they are EXACTLY the same.
I just realized an amp switcher would be pretty good for when I'm using the computer on the other end of my room, to use the rear speakers as stereo "front" speakers.
How does this work with tube amps that require a load at all times?
it has built in dummy loads
isn't most the power below 1khz? looking at your recent passive speakers reviews lowest resistance is usallly between 100hz-500hz
I grew up watching the meters on my dad's Marantz Model 500 and 510M amps, and the scope on his Marantz 150 tuner. I could spend hours sitting in front of the stereo just watching those move around.
If you don't have a meter that can reliably read 1khz AC sine waves, use a 60hz hz wave. That's not my main issue. This meter is neat, but as soon as you're not at 1khz, the meter will read wrong. I would suggest you measure the speaker, do this setup at the lowest impedance at the lowest frequency. At least then, you know when it's pulling the most power, which I think is way more neat than 1khz.
I initially calibrated the meters using my measurement hardware. I got the same voltage out reading as I did with the multimeter I showed. But yes, I’ve been told that some multimeters aren’t reliable at anything other than 60 Hz.
@@ErinsAudioCorner
Look for "True RMS" in the multimeter's specs. Most are pretty accurate up to about 400 hz.
Also the meters themselves are DC devices and do require some filtering to read accurately. So it's unlikely they can respond to anything over about 1 or 2 hz to begin with.
Calibrating at 100hz should be more than good enough.
Half the fun of mixing on a large format console is the meters!
I'm sure someone could DIY scan the output displays and make blue or white and change the lights. If they have access to a quality graphic printer thing. Or make your own with funny labels.
If you want to keep your Multimeter, switch it to AC volts *before* you connect it to your speaker leads.
Also note that the LC30 has very low sensitivity and will not properly display lower power levels. There are better and less expensive alternatives out there.
Which ones? I’d be happy to test/review some others. I like meters. 😎
@@ErinsAudioCorner
Douk audio "Little Bear" and others... have a browse over the online vendors, you'll find lots of them.
@Douglas_Blake_579 Can you please name or link to the better, less expensive alternatives you know of, thanks
@@dougbulldog9947
You know we can't post links in these comments.... right?
Go to your favourite online vendor and search for "audio power meters" or "speaker switcher" and such...
The best "budget" version I've seen is the one from Douk Audio.
As many have posted, true blind test aren’t really done in this industry. I’m talking about having an assistant set up the gear and you walk in blindfolded and sit down. No looking at the gear beforehand no idea what gear it is.
That’s why I have an ABX switcher. You never know what’s what. That’s the “X” factor. 👍
I'd like to see a test where assistant just tells changing something, but leaving everything as is.
PC load letter? What the **** does that mean?
😂😂😂
I would love to see Danny at GR subjected to some true ABX testing of his "audiophile power cords", stuff like elevating the speaker wires off the ground, and other esoteric industry nonsense. I'm sure he'd just move the goal posts though when the results didn't match his preconceived bias. 🙄🙄
I love to see him end up picking the speakers that
1. Have no no res
2. Don't have his fancy tube connectors
3. Have no fancy capacitors or crossover.
That would pretty much put him out of business, rendereing all his "improvements" bogus!!!
These guys will never subject themselves to ABX testing because they know the stakes are too high if they fail the test, and they know they'll fail the test.
Ummm, he's already done that with another skeptical UA-cam reviewer, and got like 90% correct. The reviewer conceded he made his point.
@@pnichols6500
Link please
@@pnichols6500 Link?
@@dlloyd6300 Its that Jay guy.
Back when Danny called out reviewers, him and several others came to Texas to put him to the test. Looked liked they had a good time. Probably a year and a half ago or so.
When I first saw LC30 I thought you might be reviewing the bigger brother of my LC15 guitar amp... I like Laney amps, but I don't think it'd look very hifi if you measured it on the Kippel :D
Any color... BLUE! WHITE! Subtle, but I like it. #bbn
Ok, terrific
Pretty cool.
Also, FYI, Amazon says it's unavailable.
Great if you have an empty shelf on the rack!
I tried one of these and noticed a lot of crosstalk, and the fact you cannot balance output I ended up sending it back.
It's a shame they don't know how power scaling or decibels work.
Yes, I've just upped a comment explaining this.
The difference between switching speakers should be obvious. Amps though ...
Its so cute
You probably just sold a ton of these...
Oh yeah Just bought one with black meters
Klipsch will be happy that this product is out! 😅
Many people say that the vu don't move
🤷♂️ definitely moving in the video I provided here.
@@ErinsAudioCorner
Try them with "background level" listening (half a watt or so). Even with the knob all the way up the needles barely get off the left side.
At Ali, many disappointed buyers claim that the VU meters' needles don't move.
cool gadget. and yes, it's sighted. but how hard is it to get your friend or wife to switch it so you don't know?
The problem with audio signal is that current and voltage are not necessarily in phase. Therefore a wattage meter does not show "dead current" Nice gimmick nonetheless.
Lol. G7gel incognito
I cannot see this thing being useful for identifying differences between equipment or cables. Putting a cheap box made with cheap parts in the chain will degrade a highly resolving system and smooth over differences. I guess that is good for flat earthers who like to imagine there are no differences between cables, DACs, etc.
A person who provides scientific evidence of a expensive cable not providing a difference in audio quality from a average quality cable is a flat earther?
@@danielezzet8870Zero scientific evidence has been presented that proves such a thing.
CLIP INDICATOR? Would love to have one of these switch manufacturers include a LED clipping indicator. The circuit is fairly simple, so perhaps adding it wouldn't add a lot to the cost. Many tweeters are fried by an moderately-powered amp clipping. If you think this idea has merit @ErinsAudioCorner, please pass it along to Fosi.
Clipping indicators, to be meaningful, have to be calibrated to an amplifier's output using an oscilloscope. They should start to show at about 90% of max output. You're not going to do that in a simple passive meter.
I've been over the need for Clipping and Over Temperature warnings with Fosi. I even provided documentation to show how to add it to their TPA3255 designs. The chip natively supports it, it's just a matter of implementation.
And yes, if they would include this on their amplifier designs, many tweeters would thank them.
@@Douglas_Blake_579 There is a more general way to accomplish this without having to calibrate to each amplifier. Normal audio signals, unless clipped, are NEVER flat at the top and/or bottom of their waveform (which is what you see on the oscilloscope when an amp is clipped). An op amp circuit designed to sense an even-momentary DC (flat) signal could drive/trigger an LED. It would not matter if the amp was outputting DC signal at 50 watts or 500 watts. No it is not a perfect design, but it does overcome the need for calibration. The main variable in the circuit design would be how long a DC duration would have to be present to trigger the indicator. I'd guess 6 milliseconds for starters. (And of course, no signal (0 vollts DC) would have to be ignored.) There is another more complicated way, but it would involve an analog to digital conversion.
@@michaelsparrow4798
What you are proposing is a "Peak" indicator... that's something else entirely.
To drive the meters a small bit of the speaker signal is captured and stored, usually with a simple diode and capacitor circuit. Without too much trouble a comparator can be used to monitor that as an "average level" and fire an LED if the average is exceeded by some arbitrary amount. That is more or less what the other guys are doing in their meters.
It's not a true clipping indicator since, if the average is running at a watt or so, a 5 watt totally unclipped peak can trigger the indicator. It looks cool, but it's actually pretty useless in protecting tweeters. A secondary flaw in such a circuit is that if the average is running well into clipping, the peak indicator may never be triggered because the flat topping you pointed out doesn't exceed the comparator threshold.
This is why I've been pressing these Chi-amp makers to take advantage of the TPA3255's internal analytics and external CLIP/OTW (pin 21) and FAULT (pin 19) signals to provide amplifier front panel warning lights.
In fact I have a couple of DIY versions of this on my own website. I can't post a link here or the whole comment vanishes... but Erin could, if he's willing.
@@Douglas_Blake_579 I've found that the workaround to not being able to include a URL in comments, is to specify which terms to enter into a search engine box that will result in the desired site coming up in the top 3. I'm interested.
@@Douglas_Blake_579 @ErinsAudioCorner Hey Erin. Please consider helping post this fellow's URL. Based on what he's commented, he knows of what he speaks.
Hi Erin, love your channel and all the pertanent intel you share with us. I trust your knowledge and appreciate how you explain hifi science in such a fashion that even a complete rookies like myself can actually grasp the message. I need to get some funds to you because I purchased some speakers but forgot to include your affiliate link. Are you on Facebook so I could privately message you?