This is a very intuitive video I cannot believe how simple this is I have built many Tesla coils and tune them the same way using the peak on the secondary coil to find the resonant frequency to designed the primary around I had no idea it had the same theory behind it with drivers thank you for taking the time to produce his video
Car subs tend to be tuned quite high 70/80 Hz hence the one note boom you hear from such equipment. For some reason people WITH these subs tend to feel they should share with everyone in the area! Thanks for the video John.
Michael Beeny It's no wonder as they stuff the drivers in tiny boxes. Back 20+ years ago when I was into car stereo bass, I tuned in the 40-50Hz range and used quite large vented boxes with relatively low power. With only a 15 watt per channel home made amp, I still shared the bass pretty well :)
Now they have proper drivers with efficient magnets so they can tune lower with small boxes, but parametric EQ DSP still isn't standard process unless you pay premium. Smart guys use the chinese $9 ARM based systems to process the sound.
Multimeters are usually designed to measure 50 - 60HZ on AC ranges. Some have a poor 'frequency response' below this which can skew low frequency readings.
@@qtc9231 Watch the video. At 5.04 he says "Then you want to connect a meter across the output"... A meter is also what is shown in his connection circuit diagram. Yes, has has a CRO, but many don't.
REW, room eq wizard, is free. has manually sweepable tone generator that displays exact freq, yeah it's made for this. No need to go thru quite so much creative technical improvisations, though some are still usually needed right?
My 18 inch woofer's free air resonance is 27 Hz, is it good for a subwoofer to use in a ported enclosure ? I have two 18 inches drivers and planning to build a subwoofer enclosure
Good info. I'm going to have to make that speaker job a priority, but there are so many other important or must-do jobs demanding my sparse free time. This spate of warm weather got rid of most of the snow so I was able to get some wood in and etc. Besides resonant frequency, I always thought drivers for air suspension had to be made special, more heavy duty. ?
***** Haven't seen snow down here for about a month! Yes, a lot of subwoofer drivers have heavy cones for rigidity plus the mass keeps the resonance low at the cost of efficiency.
he used his CRO not multi meter....Multi meters are calibrated to 50 or 60 hz but still you can have test using multimeter using a relative test at each frequency , that means, measure voltage across speaker terminal and them measure at amplifier output .
Hi John, Thanks for this great video! I've just succeeded to get the Fs of my speaker. Is there a way to get the other parameters needed to build a box with limited tools? I've got only a pc and a multimeter.
Unfortunately some of the other parameters are more involved to measure. They make easy to use devices to measure speakers but are only worthwhile if you have several speakers to check. Elliot Sound Products site has more info on manually measuring the parameters if you want to pursue that.
Thanks +JohnAudioTech! I'm looking for some foolproof method to determine the parameters. This is my first speaker project so investing into a USB tool as you have mentioned doesn't worth it. Anyway, I've just found out about Limp software which looks like an fairly easy way to go but I need to find some spare time to dig deeper into.
Hello Sir. I have a question. Some have suggested to keep the output AC voltage at the speaker low, something like, between 0.5 to 1 volts while doing such tests. Whats your recommendation ?
+Tiit Saul That's pretty much the last place I'd think to look for a tone generator, but if the distortion is low, why not? Clever. Of course, the output voltage is very low on most audio players, as John frequently mentions.
Very interesting!! Question - many times we see two parameters given in datasheet. Some manufacturers say as an example fs is 45 Hz and frequency range is 50-1000Hz let's say. How does it link? Does at all? Or the 50-10000 value is pure marketing? Where I want to go with this question is I would like to build open baffle speakers and want to understand what is relation between Fs and lowest reproduced frequency on -3dB. Many people tend to say that Fs should be considered as bottom line of the bandwidth for open baffle speakers (means if speaker got Fs=45Hz the lowest acceptable frequency reproduced will be 45Hz as well or slightly above). Would you tend to agree with such statement?
Amplifiers act as a constant voltage source and would make it hard to measure without the resistor using a scope. The resistor won't change the resonant frequency.
This is a very intuitive video I cannot believe how simple this is I have built many Tesla coils and tune them the same way using the peak on the secondary coil to find the resonant frequency to designed the primary around I had no idea it had the same theory behind it with drivers thank you for taking the time to produce his video
Watch at 1.25x speed for a better experience
good advise
1.5 better
Car subs tend to be tuned quite high 70/80 Hz hence the one note boom you hear from such equipment. For some reason people WITH these subs tend to feel they should share with everyone in the area! Thanks for the video John.
Michael Beeny It's no wonder as they stuff the drivers in tiny boxes. Back 20+ years ago when I was into car stereo bass, I tuned in the 40-50Hz range and used quite large vented boxes with relatively low power. With only a 15 watt per channel home made amp, I still shared the bass pretty well :)
70-80Hz? Never seen thing like this in car. Highest tunes are in 40hz range. Me and everyone I know tune
Now they have proper drivers with efficient magnets so they can tune lower with small boxes, but parametric EQ DSP still isn't standard process unless you pay premium. Smart guys use the chinese $9 ARM based systems to process the sound.
Multimeters are usually designed to measure 50 - 60HZ on AC ranges. Some have a poor 'frequency response' below this which can skew low frequency readings.
he is not measuring on a multimeter , he has got a CRO
@@qtc9231
Watch the video. At 5.04 he says "Then you want to connect a meter across the output"... A meter is also what is shown in his connection circuit diagram. Yes, has has a CRO, but many don't.
No, we have multimeters to measure higher frequencies too
Thanks for making this video! I'm trying to design a box for my car speakers and the Fs isn't a given spec. This helps a lot!
You will have to look for qts value to see wether it will sound good in the sealed or ported
NICE VIDEO thanks for sharing the knowledge
REW, room eq wizard, is free. has manually sweepable tone generator that displays exact freq, yeah it's made for this. No need to go thru quite so much creative technical improvisations, though some are still usually needed right?
Cats have a tendency to pop up to be annoying at critical moments. Sometimes I wonder if they do it to troll. Got 6 myself, lol.
My 18 inch woofer's free air resonance is 27 Hz, is it good for a subwoofer to use in a ported enclosure ? I have two 18 inches drivers and planning to build a subwoofer enclosure
You'd have to know more of the parameters but 27Hz resonance would be better suited for ported.
Hai, can you tell me how to find drive enclosure volume may be mids, mid bass or woofer with the T/S parameters?
Good info. I'm going to have to make that speaker job a priority, but there are so many other important or must-do jobs demanding my sparse free time. This spate of warm weather got rid of most of the snow so I was able to get some wood in and etc.
Besides resonant frequency, I always thought drivers for air suspension had to be made special, more heavy duty. ?
***** Haven't seen snow down here for about a month! Yes, a lot of subwoofer drivers have heavy cones for rigidity plus the mass keeps the resonance low at the cost of efficiency.
Why does the resistor have to be 8-10 ohms?
You never mentioned which setting on the meter. I assume it’s AC volts
he used his CRO not multi meter....Multi meters are calibrated to 50 or 60 hz but still you can have test using multimeter using a relative test at each frequency , that means, measure voltage across speaker terminal and them measure at amplifier output .
Hi John,
Thanks for this great video! I've just succeeded to get the Fs of my speaker. Is there a way to get the other parameters needed to build a box with limited tools? I've got only a pc and a multimeter.
Unfortunately some of the other parameters are more involved to measure. They make easy to use devices to measure speakers but are only worthwhile if you have several speakers to check. Elliot Sound Products site has more info on manually measuring the parameters if you want to pursue that.
Thanks +JohnAudioTech! I'm looking for some foolproof method to determine the parameters. This is my first speaker project so investing into a USB tool as you have mentioned doesn't worth it. Anyway, I've just found out about Limp software which looks like an fairly easy way to go but I need to find some spare time to dig deeper into.
Hello Sir. I have a question. Some have suggested to keep the output AC voltage at the speaker low, something like, between 0.5 to 1 volts while doing such tests. Whats your recommendation ?
2 volt RMS is just fine
Hi, is there any way I could find the FAr without all that equipment? I really cannot find all of those stuff unless I goto some lab or something...
6:31 thats an adlip
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there are free tone generator apps for smartphones.
+Tiit Saul That's pretty much the last place I'd think to look for a tone generator, but if the distortion is low, why not? Clever. Of course, the output voltage is very low on most audio players, as John frequently mentions.
Very interesting!! Question - many times we see two parameters given in datasheet. Some manufacturers say as an example fs is 45 Hz and frequency range is 50-1000Hz let's say. How does it link? Does at all? Or the 50-10000 value is pure marketing? Where I want to go with this question is I would like to build open baffle speakers and want to understand what is relation between Fs and lowest reproduced frequency on -3dB. Many people tend to say that Fs should be considered as bottom line of the bandwidth for open baffle speakers (means if speaker got Fs=45Hz the lowest acceptable frequency reproduced will be 45Hz as well or slightly above). Would you tend to agree with such statement?
If you found a logical answer, feel free to share it with us.
What is the purpose of the resistor? Doesn't that change the resonant frequency of the speaker?
Amplifiers act as a constant voltage source and would make it hard to measure without the resistor using a scope. The resistor won't change the resonant frequency.
Your teori can test the tweeter sir.....thanks
Haha Snickers
JBL E250P 12
👍👍👍