Back in 1995, I purchased a Velodyne F1500-R. It is STILL in use today and still looks and works like new. With that servo system, it is why Velodyne held the spot for having the lowest distortion of all subwoofers on the market at the time. What is amazing to me is, with only 250 watts, it is VERY close in output at the lowest notes (15Hz.) to my Martin Logan 1600X with ARC and 900 watts continuous. And YES, the two subs are part of two independent systems along the same wall only about 9 feet apart. Both audio systems can play at the same time and AB tests are easily done.
There was a video released a couple of months ago by a channel here on UA-cam called "Alpha Sound" where they looked at response, air and phase of a subwoofer compared to the signal by measuring the differences. Maybe not an exact answers to this question, but it touches on it and is worth a watch. 🙂
Thank you for clarifying what a Servo sub is. I keep learning new things- for some reason I thought servo sub was powered by an actual servo motor, not a servo sensor.
Interesting discussion. If it works effectively, servo corrected subs makes logical sense. Running them off the main amp also makes sense to have the sub have the same distortion as the main speakers. I don't see DSP and servos as opposing choices. DSP can correct for in room sound and servos still align sub distortion.
it doesn't have to be connected to the cone of driver you can use a piezoelectric driver connected to the cabinet ideally the front baffle, and a low pass filter fed back to the input to the amplifier will do exactly the same thing. any driver can be made into servo driver.
It doesn't even have to be an accelerometer. There are servo subs that use a secondary voice coil as a sensing coil within the motor structure. This is how Rythmik Audio does it.
Great video Paul , back in the mid 80s my father had 2 of the Velodyne servo subs , if I remember correctly they were ULD 15's with 2 M&K 12" subs and satellite speakers , for the day a truely awsome setup. I miss the days of being a kid and having the time spent going around auditioning gear and buying vinyl.
So how would you use DSP and speaker level connections? It seems to me that the DSP is either something from the preamp or a crossover component and will not be fed to the main power amp. Another thing that I'm discovering, most full range speakers attempt to produce low bass. However, as we all know, it's a real challenge. Therefore subwoofers are then dedicated to optimize that lowest octave with a dedicated, robust power amp. Wouldn't it make better sonic sense to limit the main speakers from trying to produce that lowest of bass information, thereby freeing up the main power amplifier from having to deliver that current? And the only way to do that is in the realm of line-level interface, correct?
Paul as mention this before, he wants to build dsp upper in the chain somehow, perhaps active speakers. but a purely passive speaker and normal hifi gear is a safe bet for a business and easy to use for home. as for my experience i moved over to dsp preamp unit and that is a huge step up. i have a purely digital unit, but you can easily get one with analogy output. with 4 channels you can use peq and set up high pass for mains and use any kind of subwoofer, active or passive. and most importantly have the ability to delay the main speakers. normal hifi you can only delay the subwoofers and that one are already delayed with built in dsp. also you have the dsp before the amps, so they get bandwidth limited frequency range. in my example i use a minidsp SHD studio, two dac's and two power amplifiers. digital in from a source.
A DSP in a subwoofer is a suboptimal position of a DSP in the system. The DSP will be very limited in its capabilities. It can't do anything with sound frequencies above those that just the bass can reproduce. The placement can't fix the crossover point, what order of filter, linkwitz or Butterworth should be used for your mains. The DSP can not tune your room for ALL of the frequencies that your mains are playing. That DSP can not fix the frequency response throughout your whole system. There is no way for the DSP to be able to give you different house curves more than at the bass frequency range so that they seamlessly mate with your mains when. (That would give better sound quality experience with low/high level, mixing situations.) And so on.. A subwoofer manufacturer have no other place to put the DSP plus it sells if they write DSP on the cardboard box..😅 The DSP should be in the HiFi topology were the preamplifier is today and replace it. If you want the best sound quality from a preamplifier cost no object than it is one with a DSP that offer all of the above and more! As no traditional old school preamplifier at any price can not come close sound quality wise as they have not the tenth of the required capability to do so.🎉
How do engineers decide what is the max safe input voltage to design for on a subwoofer input? A voltage that corresponds to 100 watts into 8 ohms, 28 volts, 1000 watts, 82 volts, more? Seems like using high level inputs, you would loose at least 10db of snr, and dynamic range out of your sub, just for chasing your main amplifier sound signature. But really you are adding error on error, and limiting the range. Realistically probably does not matter, but this just seems like poor choices to chase the idea of replicating your main amplifiers sound.
as long as servo and dsp can work together then i want both. does servo require analog input or digital? and i assume the servo tech needs to be integrated into the amplification or the digital conversion?
Use the line level connections. Using high-level will nake the signal go from high level (speaker level) and then to low level inside the sub amp and then gets amplified by the amp again. Makes no sense. The high level inputs today are there mostly as a backup to connect if you don't have line level out.. And line out is the exact same signal but before it is amplified by your amp or reciver anyway. And in a surround setup you would want it connected as "LFE/L+R" so it gets used for the dedicated LFE channel in movies etc and in 2.0 stereo without LFE signal it just uses left and right signal and sends that out.
Can I check my understanding here. Paul is saying that the most common method of using an rca out to subwoofer from an HT amp, isn’t as good as taking speaker cables from the front channels to the speaker inputs of the sub? Then, in most stereo or integrated amps in music systems they don’t have sub out so we should again take speaker cable out to the speaker inputs on the amp. How do we match speaker cables if we are using special speaker cables for our stereo speakers? What happens to the ohm resistance that is presumably added together front ohms plus sub ohms, maybe, 8/12/16 ohms load to the amp now. And the plate amp is not engaged. Are the sub crossovers engaged?
That's an easy one. The high level inputs to a subwoofer are merely to steal a small sample of the signal from the amp but the input impedance is so high that it just doesn't matter. Also the speaker level through and out connections are there just for convenience but do not have to be used and in fact shouldn't be used if you have the concerns that you mentioned. Furthermore since there is virtually no current passing through the wires going exclusively to the sub there is virtually no loss. However the characteristics of the stereo amplifier AS WELL AS the characteristics of the FR and FL speakers that are imparted back into the same amp WILL become part of what the subwoofer sees, therefore providing enhanced integration of the subwoofer to the system.
Think of it as low level vs high level, the amplifier inside the box for the subwoofer can often use both as input, it's just two different circuits after that to get each to the level suitable for the actual input of the amplifier. There's not really any need to match cables, and even if you tried to get the best possible option it might not be the same as what you're using for your mains (that was one of the reasons for two posts on the mains, different cables for low and high). The amount of amperes needed is next to zero (voltage is decided by the main amp). Subbass don't play the same game as the rest of the frequencies, things matters, but not in the same way. 🙂
But Paul, you have said that your use of servo designs like in the Infinity system is no longer needed. Therefore you don't use them in the Aspen F-30's. Why is that?
Hey Paul Can I Wire My Subwoofer to a Magnetometer For Deeper Passive Bass Response And If I Send This Signal Through a Optical Spectrometer and Convert The Audio Wave Signal To a Optical Frequency Receiver and Projector Would I Then Be Producing Pretty Lights That Resemble a Rainbow 🌈 of Ultraviolet’s That Goes With The Beat Of My Music 🎶 Because I Am Absolutely Paralyzed With Brain Lock if I Don’t Run This Past You….. Hey Dude Go Get a Self Powering Subwoofer and Live Happily Ever After….. What I Just Conveyed Just Think 🤔 Of It For Awhile Then Call 📞 Paul in The Morning ….Remember Through The Years Man Has Been on This Planet 🌎 He Discovered Stuff Simply By His Imagination And Serendipity And Happenstance So Plug 🔌 The Mother F@%#er In Live on The Edge Take a F@%#ing Chance Don’t Let Life Live You Live Your Life For Once I Would Like Paul To Read a God Damn Letter of Some Kid Who Stumbled Upon Something and is Now Sending Audio Frequencies Through His Microwave To His Neighbor Next Door….Please Where Is That Letter
![Is the New TCL TV Better Than Sony? TCL QM851G Review [98QM851G]](http://i.ytimg.com/vi/0FOs05NHmXE/mqdefault.jpg)
Paul, outstanding explanation....
Back in 1995, I purchased a Velodyne F1500-R. It is STILL in use today and still looks and works like new. With that servo system, it is why Velodyne held the spot for having the lowest distortion of all subwoofers on the market at the time. What is amazing to me is, with only 250 watts, it is VERY close in output at the lowest notes (15Hz.) to my Martin Logan 1600X with ARC and 900 watts continuous.
And YES, the two subs are part of two independent systems along the same wall only about 9 feet apart. Both audio systems can play at the same time and AB tests are easily done.
There was a video released a couple of months ago by a channel here on UA-cam called "Alpha Sound" where they looked at response, air and phase of a subwoofer compared to the signal by measuring the differences.
Maybe not an exact answers to this question, but it touches on it and is worth a watch. 🙂
I am so happy to have found this channel. Such knowledge shared, and the equipment… oh, the equipment… 🥰🤩
Thank you for clarifying what a Servo sub is. I keep learning new things- for some reason I thought servo sub was powered by an actual servo motor, not a servo sensor.
Interesting discussion. If it works effectively, servo corrected subs makes logical sense. Running them off the main amp also makes sense to have the sub have the same distortion as the main speakers. I don't see DSP and servos as opposing choices. DSP can correct for in room sound and servos still align sub distortion.
it doesn't have to be connected to the cone of driver you can use a piezoelectric driver connected to the cabinet ideally the front baffle, and a low pass filter fed back to the input to the amplifier will do exactly the same thing. any driver can be made into servo driver.
It doesn't even have to be an accelerometer. There are servo subs that use a secondary voice coil as a sensing coil within the motor structure. This is how Rythmik Audio does it.
@@G3rain1 yes I'm just pointing out that you don't need to have a subdriver with a coil on it that's what Paul was talking about
Great video Paul , back in the mid 80s my father had 2 of the Velodyne servo subs , if I remember correctly they were ULD 15's with 2 M&K 12" subs and satellite speakers , for the day a truely awsome setup.
I miss the days of being a kid and having the time spent going around auditioning gear and buying vinyl.
So how would you use DSP and speaker level connections? It seems to me that the DSP is either something from the preamp or a crossover component and will not be fed to the main power amp. Another thing that I'm discovering, most full range speakers attempt to produce low bass. However, as we all know, it's a real challenge. Therefore subwoofers are then dedicated to optimize that lowest octave with a dedicated, robust power amp. Wouldn't it make better sonic sense to limit the main speakers from trying to produce that lowest of bass information, thereby freeing up the main power amplifier from having to deliver that current? And the only way to do that is in the realm of line-level interface, correct?
Paul as mention this before, he wants to build dsp upper in the chain somehow, perhaps active speakers.
but a purely passive speaker and normal hifi gear is a safe bet for a business and easy to use for home.
as for my experience i moved over to dsp preamp unit and that is a huge step up.
i have a purely digital unit, but you can easily get one with analogy output.
with 4 channels you can use peq and set up high pass for mains and use any kind of subwoofer, active or passive. and most importantly have the ability to delay the main speakers. normal hifi you can only delay the subwoofers and that one are already delayed with built in dsp.
also you have the dsp before the amps, so they get bandwidth limited frequency range.
in my example i use a minidsp SHD studio, two dac's and two power amplifiers. digital in from a source.
Servo subs with a separate DSP for active crossovers.
A DSP in a subwoofer is a suboptimal position of a DSP in the system.
The DSP will be very limited in its capabilities.
It can't do anything with sound frequencies above those that just the bass can reproduce.
The placement can't fix the crossover point, what order of filter, linkwitz or Butterworth should be used for your mains.
The DSP can not tune your room for ALL of the frequencies that your mains are playing.
That DSP can not fix the frequency response throughout your whole system.
There is no way for the DSP to be able to give you different house curves more than at the bass frequency range so that they seamlessly mate with your mains when. (That would give better sound quality experience with low/high level, mixing situations.)
And so on..
A subwoofer manufacturer have no other place to put the DSP plus it sells if they write DSP on the cardboard box..😅
The DSP should be in the HiFi topology were the preamplifier is today and replace it.
If you want the best sound quality from a preamplifier cost no object than it is one with a DSP that offer all of the above and more!
As no traditional old school preamplifier at any price can not come close sound quality wise as they have not the tenth of the required capability to do so.🎉
I always connect my sub with RCA out of my preamp… high quality preamps have 2 RCA outputs …
Or 2 XLR outputs too.
How do engineers decide what is the max safe input voltage to design for on a subwoofer input? A voltage that corresponds to 100 watts into 8 ohms, 28 volts, 1000 watts, 82 volts, more? Seems like using high level inputs, you would loose at least 10db of snr, and dynamic range out of your sub, just for chasing your main amplifier sound signature. But really you are adding error on error, and limiting the range. Realistically probably does not matter, but this just seems like poor choices to chase the idea of replicating your main amplifiers sound.
as long as servo and dsp can work together then i want both.
does servo require analog input or digital? and i assume the servo tech needs to be integrated into the amplification or the digital conversion?
Infinity irs speakers were installed in the back midrange and tweeters are they connected in reverse phase
I use a REL . It's got an amp in it so id say it was active. Is a passive sub just without an amp in it?
Yes, there is no amp in it. Probably just a low-pass filter, is my guess.
Do the servos use pwm?
Use the line level connections.
Using high-level will nake the signal go from high level (speaker level) and then to low level inside the sub amp and then gets amplified by the amp again. Makes no sense. The high level inputs today are there mostly as a backup to connect if you don't have line level out..
And line out is the exact same signal but before it is amplified by your amp or reciver anyway.
And in a surround setup you would want it connected as "LFE/L+R" so it gets used for the dedicated LFE channel in movies etc and in 2.0 stereo without LFE signal it just uses left and right signal and sends that out.
Can I check my understanding here. Paul is saying that the most common method of using an rca out to subwoofer from an HT amp, isn’t as good as taking speaker cables from the front channels to the speaker inputs of the sub?
Then, in most stereo or integrated amps in music systems they don’t have sub out so we should again take speaker cable out to the speaker inputs on the amp.
How do we match speaker cables if we are using special speaker cables for our stereo speakers?
What happens to the ohm resistance that is presumably added together front ohms plus sub ohms, maybe, 8/12/16 ohms load to the amp now. And the plate amp is not engaged. Are the sub crossovers engaged?
That's an easy one. The high level inputs to a subwoofer are merely to steal a small sample of the signal from the amp but the input impedance is so high that it just doesn't matter. Also the speaker level through and out connections are there just for convenience but do not have to be used and in fact shouldn't be used if you have the concerns that you mentioned. Furthermore since there is virtually no current passing through the wires going exclusively to the sub there is virtually no loss. However the characteristics of the stereo amplifier AS WELL AS the characteristics of the FR and FL speakers that are imparted back into the same amp WILL become part of what the subwoofer sees, therefore providing enhanced integration of the subwoofer to the system.
Think of it as low level vs high level, the amplifier inside the box for the subwoofer can often use both as input, it's just two different circuits after that to get each to the level suitable for the actual input of the amplifier.
There's not really any need to match cables, and even if you tried to get the best possible option it might not be the same as what you're using for your mains (that was one of the reasons for two posts on the mains, different cables for low and high). The amount of amperes needed is next to zero (voltage is decided by the main amp).
Subbass don't play the same game as the rest of the frequencies, things matters, but not in the same way. 🙂
But Paul, you have said that your use of servo designs like in the Infinity system is no longer needed. Therefore you don't use them in the Aspen F-30's. Why is that?
servos require amplification and he wanted to make a passive speaker, think active woofer section was tested at one point
Neither: Rel Carbon Specials
JLA cr-1 active crossover 😊
Shunyata Research Python xlr's
Hey Paul
Can I Wire My Subwoofer to a Magnetometer For Deeper Passive Bass
Response And If I Send
This Signal Through a
Optical Spectrometer and Convert The Audio Wave Signal To a Optical Frequency Receiver and Projector
Would I Then Be
Producing
Pretty Lights That Resemble a Rainbow 🌈 of Ultraviolet’s
That Goes With
The Beat Of My
Music 🎶
Because I Am Absolutely
Paralyzed With Brain Lock if I Don’t Run This Past You…..
Hey Dude Go Get a
Self Powering
Subwoofer and Live Happily Ever After…..
What I Just Conveyed
Just Think 🤔 Of
It For Awhile
Then Call 📞 Paul in
The Morning
….Remember
Through The Years
Man Has Been on This Planet 🌎
He Discovered Stuff
Simply By His Imagination And Serendipity And Happenstance
So Plug 🔌 The Mother
F@%#er In Live on
The Edge Take a F@%#ing Chance
Don’t Let Life Live You
Live Your Life
For Once I Would Like Paul To Read a
God Damn Letter of Some Kid Who Stumbled Upon Something and is Now
Sending Audio Frequencies
Through His Microwave To His Neighbor Next Door….Please Where Is
That Letter
?