Do you think you need a subwoofer?

Dear friends: There are at least to things to share with you that I forgot:

- many people that own active subwoofers in their stereo audio systems speak on that thunderous bass that they don't have it before the subs in their systems and some of them speak to about that the room or diferent home items  in the room " shake/rattle " with their subs. Some like to talk about.

Well, I have not that shake/rattle or thunderous sound/reproduction in my system any more.
That kind of " events " are caused by high distortions in that frequency range but does not comes in the recordings and if some are experienced that they have an audio reproduction problem and certainly very low quality level on what are listening, it does not matters if they all are satisfied.

- the other issue I forgot is that inside my whole tests process exist the digital/CD tests that with out it any analog tests process is totally incomplete.

Testing bass range nothing can compare with the digital alternative that when with good recordings is way superior to analog and not only this but if we want to know how bass range must sound we must to listen to CDs and learn about.
I have several digital tracks that I always use trhough that whole tests evaluation's process and not only for the bass range but in this precise bass subject two of the recordings I use are: The thin red line and Gladiator ( I own " hundreds " of excellent CD that can show me what I'm looking for. ) that I know really good and what I can tell you is that the pristine, crystaline and precise definition and extremely high resolution is just: ASTONISHING.

The good " news " is that not only in the bass range but in the overall frequency ranges ! ! ! !


Thunderous bass does not comes in the recordings, it's generated on purpose by. In a home system comes for very high distortions in more than one system link and for the room interactions with.

Thunderous bass exist only in the nature through: sound on the Niagara falls or a thunder.

My take is that if we don't improve the quality level of each one bass range system/room reproduction it does not matters what we can do in the other frequency ranges our quality system levels will stay in average status.

I think all of us must have to take care more deeply on that system/room bass range reproduction !!!!

Regards and enjoy the music,
R.

Raul:
"According to scientific studies four subs are optimal in a home audio system."
     
     As a user of the 4 sub approach for the past year, I can attest to the validity of these scientific studies.  I've found the 4 sub approach has been an excellent solution for bass performance in my 23' x 16' living room.  My system is used about equally for 2-ch music and 5.1 surround HT.
     I use an Audio Kinesis Debra distributed bass array system that consists of 4 non-amplified subs (each sub is ported, has a 10" driver, weighs 67 lbs. and measures 23.75″ x 14.5″ x 10.375″) and a 950 watt class A/B amp with variable crossover and phase controls. Total price for the system is $2,990 and there is a choice of woods.  

       I was originally considering getting 2 high quality powered subs like JL, REL or Vandersteen but discovered the Debra 4 sub system while reading about the scientific studies that Raul references above. 
     These were studies by Acoustical Engineers Dr. Geddes and Dr. O'Toole that were concerned with bass wave propagation in residential and commercial spaces.  Here's a summary of their key conclusions:

Sound waves behave differently in typical rooms below and above about 200 hz.

Low frequency sound waves are so long ( a 20hz sound wave is 56.5 ft. long) that they'll bounce off room boundaries until they run out of energy.

These initial and subsequent long bass waves eventually overlap and meet which creates standing waves at various points in a room.

These standing waves result in bass peaks (perceived bass overemphasis) bass dips (perceived bass under-emphasis) and even bass cancellations (no perceived bass) at various points in a room.

They were able to mathematically predict and plot precisely where standing waves, and their corresponding peaks, nulls and cancellations, would exist in a room based on the location and number of bass sources (subs), bass frequency, room dimensions and boundary materials,

They found a relationship between the number of bass sources(subs) in a given room and the resulting number of standing waves in the room; Basically, the more subs in a given room the fewer bass standing waves are created and the better the bass.  

They note that there is, of course, a practical limit to the number of subs users will deem acceptable.

As a result and perhaps the most crucial conclusion they reached
 concerning the use of subs for residential and commercial spaces, was that the use of 4 subs in a given space resulted in the elimination of the vast majority of bass standing waves in that space. Each additional sub beyond 4 only resulted in marginal improvements.

     The DEBRA and SWARM distributed bass array systems are both based on the Geddes and O'Toole studies and conclusions and they both, unsurprisingly, utilize 4 subs.

     I honestly believe it would be almost impossible to overstate how well the DEBRA system has improved the bass performance in my room for both music and HT.  I use Magnepans for my L/C/R channels and, as many of you know, they have been notoriously difficult to integrate with subs.  The bass is solid and tuneful for music and powerful, impactful and even startling on HT.  

     With so many people using bass traps, microphones, room analysis and correction software, equalizers and digital signal processing to improve low bass performance in their rooms, I find it ironic and a touch humorous that the best solution available thus far is adding more subs.

     I don't want to leave the wrong impression, I am not wealthy and $2,990 for a sub system is expensive to me, too.  I rationalized the cost as being less than the cost of 2 high quality powered subs and that it's likely the last bass system I'll need to buy.

     The progressive and precise setup procedure is fairly elaborate and took me most of an afternoon to complete.  The subs are wired in parallel and it's recommended that 1 sub have its phase inverted.


Thanks,
  Tim   
    

Forgot to state some disclaimers:

     I have no association with, or financial interest in, anything to do with distributed bass array systems whatsoever.  I am just a very satisfied user and big fan.

Tim

Dear @noble100  : The corrupted AHEE where like it or not all audiophiles are inside teached us stay away of subwoofers in a home stereo audio system.

The audiophiles were educated in that way and even today several of them are sticky to that information.

Not only that but the name JBL was a forbidden one by that same corrupted AHEE.

Well several years ago was precisely at JBL where took one of those scientific studies on the precise convenience to install multiple subwoofers in " domestic " enviroments and its full non-refutable advantages.
These people not only make the mathematics modeling of that subs subject but they tested LIVE at its unique audio research installations/facilities.

As a part of that AHEE I never thougth or passed for my mind to install subwoofers in my home system, so I just let it gone till my " curiosity " ( many years ago too. ) to think and test " out of the box " made it that I bougth two Sweden active Audio Pro 10" subwoofers that because my very high ignorance level on the subs subject did not worked in the rigth way.

Anyway, latter on I insisted on the subject and installed my today active subwoofers that I took around one year for been totally room/system integrated with out room treatment or equalization of any kind.
In the mean time and before I sold those two Audio Pro I connected it along the Velodynes and again because my high ignorance levels the Audio Pro gone but I remember that in one of my several tests I put the Audio Pro at both sides of my seat position ( very near. ) and I could not detected its reproduction sound but was functioning onn.

Time latter and through my Velodyne's adventure I learned that the myth that over 30-40hz the bass has directionality comes down totally falls that myth because even  at 80-90 hz you can't detect it if exist good system integration.

For years in this and other threads, even in my latest posts here, I touted that the more critical an important home system frequency range is the bass one that with out a true high quality performance in that range what we are hearing is the system room with a really " poor " quality level performance even on system in the 300K prices.

I just can remember an Agoner that a few weeks ago I send him an email trying to help in some ways for his system truly shines: he owns  a very high price beautiful system with Magico speakers I think the 3 or 5 model and what I email to him was the integration of two subwoofers in his system.
I think that because that very high price on his system and because the ignorance level we all have because that corrupted AHEE he never gave me any single answer not even: thank's but NO.

That's why we audiophiles just do not grow up even that we think we are growing up ! ! !


I notice in the past your today subs kind of set up and yes I know exactly what yoi mean and enjoy and what those gentlemans really know on the overall subject. Thank's to share with all of us here.

If you note no one else but @stringreen  and you posted and I wondering if each one of aall those Agoner's ignorance levels on the bass management subject is so high that has nothing to share, comment or ask ! ! !
Always posted and post here that every single day is a learning one for me that always am open to all audio experiences from other gentlemans.

Now and ccoming back with that " thunderous " kind of sound in home audio systems:

I already said thet all comes from very high distortions that only happens in home audio systems. Let me explain my take here:

maybe some peole other than me already experienced the " fall " of a live thunder at near field from us. What can we remember about other that the very high SPL of the sound ( " fundamental " notes " ) ?: NO SINGLE VIBRATION/DISTORTIONS.

What if in the same example/experience we are at 200 m.?:

thatwe feel those vibrations/distortions/resonances all over our body. From where are coming in this example?:

it came from the enviroment that's " exited " by those fundamental/harmonic notes and that were " builded " through the " distance ".

Here the " distance " is our each one ROOM and it does not matters how we make the room treatment or equalization never really disappears and can't disappears because the bass range system ( not room. ) reproduction has " poor " quality levels.
This " poor " quality levels comes from each and all single link in the system chain. 

 Obviously than in the analog alternative is way " poor " than in the digital one and it does not matters what you think in this digital subject.

All analog lovers ( like me ) always try to have the best front end with distortions at minimum, our main concern belongs " there " and we don't take with the same " passion " the other links and especially electronics ones.

Why I mentioned electronics? because all the information is " processed " down there and we need at least that those electronics ( Phono line preamp, phono stage, line preamp or amps. ) where designed to performs from 1 hz to over 200 khz and with almost negible distortion/noise levels and that that frequency range be really flat. This must be not only our targets but the target of electronics manufacturers. Yes, additional must be a very good design and with high quality design excecution.

We can think that any kind of electronics can do it but not really. Of course thatalmost any item can have those characteristics with huge deviations on the freqency range.

Which are the precise and rigth electronic alternative we all have on " hand " to use it any time we want it?:

ONLY ONE alternative: SOLID SATE DESIGNS.

For the bass range be reproduced in precise way we need SS electronics, tube alternative is for anything you want but to handle the bass range that is where is the home system foundation.
No, hybrid designs does not meet the targets because it can't do it, is a limitation of the tube technology.

We have to remember here that what we want is not to hear/listen/enjoy the ROOM but the recording.
@lewm , you can't do nothing about and don't be angry with me again for that tube subject.

I can prove to any one what I posted here even to electronics tube designers that I respect for they shared their knowledge level on their designs. Please don't forgeret that I used for many years tube electronics and I'm not against tubes but in favor of MUSIC and what's in the recording.

There is a MoFi old recording name it: The Power and Majesty that it's in my personal evaluation tests/tracks process and is really a bass management and its meaning on almost all I posted here and this recording can tell you if our system is performing with high or poor quality level: if you know what to looking for.

Same with the several CDs tracks I use in my evaluation home  systems process: to know what to look for. 


Btw, already arrived my two 2.8 kwatts regulators. I'm with some " doubts " if it will works because my amps are fully regulated. I will connect it in my system after take a look inside the units and if I can make some tweaks down there.


Regards and enjoy the music,
R.

Raul, I agree.  For clean low bass, SS is best.  Also, I like and respect Duke Lejeune very much, and I applaud his success with AudioKinesis.  My problem when it comes to placing four subwoofers in my living room is where to place them.

But in my Beveridge system, I use a Threshold amplifier to drive my home-made transmission line woofers for all frequencies below about 100Hz, and the results are excellent. Dahlquist crossover receives the output from the preamplifier and provides the signal to the Threshold.  All solid state.