Dear friends: Here and in the other subwofer threads I read almost everything to learn about subwoofer ( mainly placement. ) but I wonder why ( you that use it ) to use subwoofers in a music dedicated stereo system, even if we own full range speakers. Which answers do you have?.
regards and enjoy the music,
Well this is my answer, this is what I found ( and share. ) through my experiences trying and achieving the seamless integration of two separate and self powered subwoofers in a true stereo fashion to my full range passive loudspeakers:
Why it is important the use of subs on our home stereo audio systems ?
Well, for we can hear what is on the recording ( analog / digital / any ) we need a series of links ( audio items ) to build the whole chain for the music/sound reproduction.
All the links on the system chain are important and all of them have their particular distortions that put the " colors " to our " audio pictures ".
In this audio chain, in the analog case , the most imperfect links are at the front end: phono cartridges and the speakers. Here is where we have a lot of distortions ( of any kind ) because these audio music " transducers " are truly an imperfect ones against electronics ( for example ). So, for me, these are the " tweak " links on the audio chain.
In this forum all of us already learn how to improve the cartridge link for a better music/sound reproduction ( less distortions ), but not many of us take care about the speakers distortions, other than the room interaction, that really " color " the final sound that we hear.
Why we take care about: VTF, VTA/SRA, Overhang, resonance tonearm/cartridge, SUT or not SUT, unipivot, air bearing, cables, tubes or not tubes, SS, DAC's, CD transports, and the like when all what we do can be corrupted at the end of the audio chain with full of speakers/room distortions.
Where the subs can help us ? :
Intermodulation Distortions: Almost any three ways speaker ( all two ways/one way ) has it's crossover frecuency ( low driver ) between 150Hz and 450Hz. I can assume that any of ours speakers system goes down flat ( at least ) between 60Hz to 20Hz.
What does that means ?, well that a single driver has to reproduce frecuencies/harmonics from 20Hz/60Hz to 150Hz/450Hz. With that kind of frecuency range here exist a great intermodulation distortions that put it's " color " on the sound reproduction.
You have to imagine that that single woofer/driver has to reproduce, at the same " time ", a 30Hz frecuency along a 350Hz frecuency: here is where exist that IM that gives heavy distortions in what we hear ( there is no perfect driver: moving coil, electrostatic, ribbon, etc.. The speaker designers has to choose the best " trade offs ", but the distortions are there. ): less clarity, less resolution, less precision, less natural balance, less pitch, les, less, less......., and this is what we are really hearing: LESS MUSIC.
If you read any manufacturer specifications on their speakers they never " write " the value of the IM or harmonic distortions, they tell us the frecuency range and how is flat on that range but never " talk " about distortions. I think that you know that when we have a speaker frecuency specifications, say: 28Hz to 22kHz +,- 3db, that is a very nice spec, that speaker low driver don't stop at 28hZ it's goes a few hertz below that frecuency with heavy harmonic distortion that increase the IM distortion of the sound reproduction of that driver and these additional distortions have a severe degradation in the reproduction of the MUSIC.
What happen when that low driver is free from those frecuencies ? ( main speakers: monitors or full range, it does not matters. My main speakers are flat to 22Hz and only 5db +.- at 18Hz and I have benefits with the seamless subwoofers integration to my system ), below 80Hz ( this is the crossover frecuency that I find the best point to start to blend a subwoofer. ):
SUDDENLY the " lights are on ", your music/audio " life " its born: the mid bass is clean, the midrange is clean, the highs are clean: high resolution every where ( the distortions are almost gone ), and now you can really hear for the first time the MUSIC through your home stereo audio system: what a pleasure!!!!!.
This is truly a discovery for all of us that cares about MUSIC. We really discovery what kind ( quality/quantity ) of audio system we really have ( now we can do any evaluation of any audio item, not before. ) and where to work for a future improvements.
Now that we already settle in the subwoofers ( self powered ) with our main speakers ( yes, it is a hard work to do. We need at least: very good ears, love for music, experience with live music, patience, time and good muscles. We have to work with: location of subwoofers and the main speakers too, phase, crossover frecuency, volume/gain. We need two subwoofers not one and this issue is critical. TIP: avoid the common asumption that the crossover point should be at the low frecuency flat response of the main speakers, example: the speakers are flat at 40Hz, then you choose 40Hz for the frecuency crossover between the subs and the speakers, this is a great mistake: remember that we use subwoofers not only for a better and extended low bass but for a better midrange/midbass too. So, the frecuency crossover will be over that 40Hz: not at 40Hz or below 40Hz. ), we have others advantages:
- better quality low bass ( you can have at least one more octave ) and mid bass ( quantity? : you choose it: volume/gain ) ). Now we can heard the " foundation " of the MUSIC ( and its harmonics ) and this single issue is stunning for the pleasure to hear any kind of music. Now, we are nearest to the " real MUSIC ", nothing less.
The first time you can hear the subwoofers right blended on your stereo home audio system: YOU NEVER COULD LIVE WITH OUT THEM AGAIN, ANY ONE CAN.
- An improvement in the soundstage reproduction in all parameters: deep, front/side location, wide of the stage, etc...
- the main speakers amplifiers works best ( less distortion, more headroom, less chance of clipping, less amplifier stress, etc...) with out to handle the frecuencies range that now are handle by the dedicated subwoofers amplifiers. This is important for an SS amplifier but for the tubes ones is a must.
- Now the low bass frecuencies are handle for a dedicated driver that was build with specifics characteristics for to work in that frecuency range and this low bass driver is matched with an amplifier ( self powered subwoofers ) that was build with specifications that mates excatly what the low bass drivers needs about: frecuency response, output impedance, damping, power, etc..... You can't ask for more!!!
- Not only the IM distortion goes down but the harmonic distortion of the low driver of your main speakers goes down too.
- Usually the location of the speakers in our room ( with out subs ) is a " compromise " ( trade off ) between the best performance at the bass against the best performance at the mid/high frecuencies ( only in a few cases the location is with out any " trade offs ". ), when we integrated the seamless subs in our audio system we can have the best of both " worlds " and you will be in " heaven ", now we can put the main speakers in the best room location and the low bass drivers ( separate subs ) in its best location too!!!
Some people use subs with their full range speakers (FRS ) as a bass reinforcement, this IMHO is a misunderstood that can do more harm that any good to improve the system quality performance:
maybe is not very clear about the seamless integration in a true stereo fashion of powered subwoofers with " full range " speakers like Dynaudio Evidence/Temptations, Dali Megaline, Wilson Maxx3/Alexandria, etc, etc,...
We can think that with a FRS the integration of two powered subwoofers can't do any help to improve the quality sound reproduction. I can tell you that even with FRS the integration of subs can help a lot, let me to give my opinion about::
- That elusive full octave in the low bass is a headache for any one, especially for the loudspeaker manufacturers: they have to choose very carefully the right trade-offs about.
In the other side, we the FRS customers have to choose the right amplification device for really " take-out " and " live " that marvelous low bass reproduction through those passive FRS: a very hard task, it does not matters the speaker design and the amplifier design.
- There is no single external / stand alone amplifier that can work or do a better job than a low bass dedicated amplifier like the one that comes with a powered subwoofer:
think that this dedicated bass amplifier was designed/tailored to match every single woofer parameter: impedance, frecuency response range, damping, power, distortion, etc, etc,...
- It is not only this dedicated amplifier what makes this subwoofer approach/technology ideal to handle the low bass octaves.
The driver/woofer is designed/tailored too for that specific low frecuency range.
There is no passive FRS, at any price with any amplifier, that could beat a self powered subwoofers in that frecuency range. When you have and hear the subs on your system you never can live again with out those subwoofers.
Here we have to remember other important issue: the best subwoofers are SERVO CONTROLLED, this characteristic give to the subwoofer a heavy advantage over a passive FRS about the low distortion that a well designed subwoofer had against a higher distortions on any passive FRS. The Velodyne unique design permit that woofer driver control through that the signal is " measured/tested " 10,000 each second to control the woofers " behavior ", this permit that Velodyne sub's has an impressive ( lower than ) 0.5% on THD where other sub's like the JL Audio ( new " toy " in the block ) has 6%!. This sole spec made a difference in quality performance for the better in the Velodyne's that btw many people thinks are " mid-fi " and this kind of thinking is IMHO a misunderstood or low knowledge on the whole subject. Btw, the Velodyne's are sealed design that in my experience performs with better quality than " ported " sub designs.
If is true that sub's place is very important issue IMHO in a two speaker system ( for music listening. ) the choice of subwoofers is critical and important too. With HT almost any sub's can works but in a two speaker system IMHO we have to look for the best quality performance in that foundation music frequency range and its main contribution to the overall system sound so we have to take care on our each one sub's choice.
In any case, true advantages on seamless integration of two powered subs in true stereo fashion:
- lowest speaker system Harmonic Distortion and IMD.
- better low bass quality.
- deep/and lower bass frequency response.
- right low bass system/room quantity.
- better system mid bass, mid range, hf, soundstage, etc quality performance.
- higher system SPL/headroom with lower overall distortions.
- better amplifier main speakers performance.
- better main/satellite speakers quality performance too.
- better speaker system room integration.
- better, better, better, etc, etc.
this is what I learn about: a full and better home audio system quality performance !!!!!!!
Regards and enjoy the music,