Who's arguing? I'm pointing out facts.
The truth about subwoofers
- Thread starter JoeESP9
- Start date
What was that you said about JL Audio? Facts, r i g h t lol.
JL AUDIO GOTHAM G213V2 DUAL 13.5" SUBWOOFER
- Regular price$16,500.00
look at all those speaker inputs
As I stated, truly high end eschew speaker level inputs. True, some have been adding them in the hopes to sell more units to the masses with lower end gear without pre outs like many receivers/integrated amps, but those in the know realize the signal directly off a preamp is cleaner with a much lower noise floor and less colored signal.
ya, there's the bullshit theory this helps to integrate the sub, but it's just that, BS. Everywhere else in the signal path we look for purity in signal, but here, in this one case it's preferable to have a dirty colored signal?
It's much more important to give the subwoofer amplifier "the identical signal" the main amplifier is receiving, not some ambiguously dirty signal if wanting a truly clean presentation.
That's it, I'm done with this, this has been hashed over in many threads here at AK, not getting into this again, that's the argument you were wanting, again.
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melvinjames
Well-Known Member
I've read this countless times over the years and I still have a hard time wrapping my head around the "voicing" part. Perhaps I don't understand the meaning of "voicing" or I'm just dense. (I'm not a speaker designer nor an engineer, just a passionate hobbyist.) Right now I have my sub connected via high-level to good effect BTW, but I've also used the low-level connection as well using Decware's switch box. What escapes me is how the tube signature from my Decware amp is retained when the signal is then amplified by the sub's amp?
Everything has a sonic transfer function (it changes the sound), inherently causing variations from absolute flat response in frequency and time. The "voicing" comes from the effects of this transfer function. Some more than others, but everything to some degree.
One of the things that makes integration of subwoofers more difficult, is different transfer functions between the driving electronics. If an amp has one signature, and a second has another- then combining two sources, one driven by each different amp, will cause at least some interference somewhere in the spectrum, in frequency, time, or both. It may be obvious, or it may be subtle or even un-noticed- but it is always there.
You can't remove the subwoofer amp's signature- but at least, you can ameliorate the differences, by having it at least contain the transfer function of the main amp as well. This will make the blend between the sub and the main speakers, at bit more 'seamless'.
Of course- if the main speakers and the subwoofer, could, somehow, be driven by the exact SAME type of amp- then there would be no need to feed the sub through the speaker input. But, as long as the amps are different- especially in the case of one being a tube amp and the other a solid state amp (which will have pretty different transfer functions)- then feeding the solid-state sub amp, from the speaker feed of the tube amp, will usually make for a better blending between the subwoofer and the main speakers, due to the transfer function the tube amp being carried through everywhere.
Regards,
Gordon .
One of the things that makes integration of subwoofers more difficult, is different transfer functions between the driving electronics. If an amp has one signature, and a second has another- then combining two sources, one driven by each different amp, will cause at least some interference somewhere in the spectrum, in frequency, time, or both. It may be obvious, or it may be subtle or even un-noticed- but it is always there.
You can't remove the subwoofer amp's signature- but at least, you can ameliorate the differences, by having it at least contain the transfer function of the main amp as well. This will make the blend between the sub and the main speakers, at bit more 'seamless'.
Of course- if the main speakers and the subwoofer, could, somehow, be driven by the exact SAME type of amp- then there would be no need to feed the sub through the speaker input. But, as long as the amps are different- especially in the case of one being a tube amp and the other a solid state amp (which will have pretty different transfer functions)- then feeding the solid-state sub amp, from the speaker feed of the tube amp, will usually make for a better blending between the subwoofer and the main speakers, due to the transfer function the tube amp being carried through everywhere.
Regards,
Gordon .
It doesn't, it's just added noise. This myth was started by Rel, it's just snake oil.
I've stated over and over, I've used both, and I'm currently using both methods. But I'm not fooling myself into believing feeding one power amplifiers high output into another amplifier is better than feeding both with the identical signal directly from the preamp. My subs connected high level are mated to the mains in my surround setup, not my critical 2-channel setup.
I wonder why all power amps don't have speaker level inputs
, why not daisy chain a Krell, Sansui, Kenwood, etc, etc, adinfinitum to get the flavor of all, now that's the **** eh?This will be argued forever because many hear not as good as bad, that's not the case. Both will work just fine, just one has less noise.
Well, this:
... is about as far as you can get from a sub "made for the masses". Note that it DOES have high-level inputs- for the reasons expressed just above. In fact, note that it ONLY has high-level inputs- most of the Von Schweikert Audio subs sold, are configured just this way.
The 12" version (Shockwave V12XS) is $11500.00, and the 15" version (V15XS) is $16000.00 And, almost always, two are used in a system, for better control of room modes and better distribution of room bass level, and to allow each sub to feed from one channel of the audio (the left sub from the left speaker feed, and the right sub fro the right speaker feed).
As mentioned before- these are the same type subs that have been incorporated into systems, that at major audio shows, such as Munich High End, AXPONA, Rocky Mountain Audio Fest, and such, have taken repeated "Best of Show" awards from all of the major audio publications, on multiple occasions. They must be doing SOMETHING right...
Regards,
Gordon.
It doesn't, it's just added noise. This myth was started by Rel, it's just snake oil.
I've stated over and over, I've used both, and I'm currently using both methods. But I'm not fooling myself into believing feeding one power amplifiers high output into another amplifier is better than feeding both with the identical signal directly from the preamp. My subs connected high level are mated to the mains in my surround setup, not my critical 2-channel setup.
I wonder why all power amps don't have speaker level inputs
This will be argued forever because many hear not as good as bad, that's not the case. Both will work just fine, just one has less noise.
Straw-man argument.
Daisy-chaining amps has no purpose- if they're all driving the same single speakers.
The practice of using high-level inputs ONLY has a benefit, when you're trying to integrate separate and multiple speakers, each helping produce part of the same signal, in the same room. It is demonstably beneficial to have each driver in the system, being fed as close to the same exact transfer function as possinle.
BTW: I actually built my own custom setup, to allow my subwoofer amps to be driven from the speaker outputs (modded HK A300 tube amp driving custom Tannoy speakers, with custom subs built into the rear wall of the listening room) in my own system. It did integrate FAR easier and more seamlessly (it's impossible to tell where the subs are in the room, from just listening- the only way to know they are there, is when you miss them when I turn them off), that way.
Regards,
Gordon.
melvinjames
Well-Known Member
Thank you guys .. much appreciated.
If you're familiar with biamping then you know it's using more than one amp to drive the speakers. Typically one amp to drive the woofer, and another the higher frequency drivers.
There are other arrangements but this most helps to illustrate the use of a subwoofer. Often when a tube amp is utilized in the biamping it's for the high frequency drivers to add the tube warmth, but solid state is retained for the woofer for its perceived tighter control over the larger driver, no issues with integration.
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Congrats, you found one. As for the rest....lol.
Unless the gain levels are matched there will be issues with integration.
For each their own- but I've never been satisfied with using a tube amp straight from the preamp for the highs, and a SS amp straight from the preamp, for the lows, in any bi-amp situation I've worked with. You could ALWAYS hear the difference between the damping and the transient response between the two- they never seamlessly integrated, to my satisfaction.
It's less noticeable for a sub (low frequency crossover)- but if you get up into the midrange for the transition- it's especially distracting and detrimental.
This is one reason why some of us, have only been half-jokingly bugging Kevin Hayes of VAC every now and then, to build a dedicated tube subwoofer amplifier. Then, integration with other VAC amps would inherently not be an issue. I recognize that it's a long shot that this will ever happen- but boy, it would be the ultimate solution.
Regards,
Gordon.
The problem with your argument is that you are looking at only one side of it. Of course there is more "noise" when driving the sub with the main speaker outputs because that signal is going through the preamp and the amp, instead of just the preamp. That said, the additional "noise" of the amp is negligibly small in any decent system. If there was any meaningful noise from the amp, you'd hear it a hundred times more out of the main speakers than you would out of the sub (take a look at typical THD of the audio out of subs if you doubt this). Unless you are driving the amp to its limits, there won't be any meaningful noise at all in the mains, and it would be far less audible in the sub. I fully agree with you that the preamp signal is unquestionably cleaner, on a theoretical basis and even a measurable basis, but that difference means nothing in the real-world in terms of what is audible (unless you have a defective or overdriven amp).
The side of the argument that you are ignoring is that driving the sub with the main speaker outputs allows the sub to see the exact same signal as the mains. Whatever interaction there is between the amp and the speakers, and whatever coloration is in the amp, will be seen directly in the signal fed to the sub (just as it is fed to the mains). The advantage of this, at least in theory, is that using the high-level inputs allows the subs to act more like an extension of the mains (it's only purpose in a 2-channel system) because both mains and sub see the exact same signal. When you drive with the preamp, that preamp circuit (while theoretically cleaner) is completely divorced from what is happening between the power amp and the main speakers. It's a cleaner signal from the preamp, but it's less reflective of the signal the main speakers are driven by.
The preceding outlines both sides of the theoretical argument. Everyone should test both if they can (and are inclined) to see which theoretical side bears out more in their real-life environment for their individual components.
My experience, and I believe the universal experience, is that the tiny, tiny bit of "added noise" from using speaker-level is totally inaudible in any quality system. My experience is that driving a 2-channel sub with speaker-level does make the sub more integrated with the mains. Others might have a different experience -- I wouldn't argue one way or the other for anybody else's circumstances. What you can't do, though, is make only the "cleaner" side of the argument while ignoring the "subs and mains seeing the exact same signal" side of the argument.
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Tube Radio
Super Member
The phase shift of an amp is indeed very important when integrating a sub.
In two instances I got the phase shift of two amps to be 0 degrees at 70Hz (crossover point I use for subs) and the phase shift of two plate amps to be 0 degrees at 20Hz on up to 70Hz and the subs and mains integrated so well that the subs disappeared and I only heard the bass and when I turned the plate amp off it sounded just like I had turned the bass control down on my preamp.
One uses speaker level inputs on the plate amp and a cap in the speakers to form the necessary high pass filter. The other uses a two way 24 db/octave active 70Hz crossover and both sound great.
The active crossover one is better as it's at home and I have four bucket subs spaced in the room.
The other one is at work and is a single 10" sub
In two instances I got the phase shift of two amps to be 0 degrees at 70Hz (crossover point I use for subs) and the phase shift of two plate amps to be 0 degrees at 20Hz on up to 70Hz and the subs and mains integrated so well that the subs disappeared and I only heard the bass and when I turned the plate amp off it sounded just like I had turned the bass control down on my preamp.
One uses speaker level inputs on the plate amp and a cap in the speakers to form the necessary high pass filter. The other uses a two way 24 db/octave active 70Hz crossover and both sound great.
The active crossover one is better as it's at home and I have four bucket subs spaced in the room.
The other one is at work and is a single 10" sub
Tube Radio
Super Member
Has to do with phase shift in addition to what you mentioned.
If more people would understand just how important phase shift in an amplifier is, they would wind up with much better subwoofer integration.
Phase shift could be why some have a problem with subs as the sub isn't integrated well and cannot be made to be integrated well until the phase shift is taken care of.
not missing anything, the sub driver is seeing a completely different signal than the mains in your scenario, it's seeing both amps where the mains are not, and the sub amp is seeing a completely different signal than the main amp, nowhere is this a good thing.
if you think it is you're fooling yourself
members here are concerned with the added affects from an additional foot of interconnect and it's a good thing to put an amplifier and 10 feet of unshielded speaker wire in the line lol? let's go with that.
Done, this argument has been hashed out dozens of times here on AK, it's a moot point.
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Tube Radio
Super Member
Grenadeslio, the reason in your case the speaker level inputs sound better is because of the phase shift in the main amp. With the sub amp connected that way it has the same phase shift at the crossover point so it will sound better.
However if one eliminates all phase shift from an amp and subwoofer amp then it won't much matter if high level or line level inputs are used.
With speaker level inputs one has to be sure the mains have a capacitor that forms a crossover at the desired crossover frequency for the subs and when using line level inputs a good quality 24 db/octave active two way crossover must be used.
However if the subwoofer is crossed over at where the mains start to drop out then no real crossover on the mains or main amp is needed.
However if one eliminates all phase shift from an amp and subwoofer amp then it won't much matter if high level or line level inputs are used.
With speaker level inputs one has to be sure the mains have a capacitor that forms a crossover at the desired crossover frequency for the subs and when using line level inputs a good quality 24 db/octave active two way crossover must be used.
However if the subwoofer is crossed over at where the mains start to drop out then no real crossover on the mains or main amp is needed.
Tube Radio
Super Member
Think that may have been the other guy you quoted.
edited my last post, read post #165
