Do you think you need a subwoofer?


Why almost any one needs subwoofers in their audio systems?

I talk with my audio friends about and each one give me different answers, from: I don't need it, to : I love that.

Some of you use subwoofers and many do in the speakers forum and everywhere.

The question is: why we need subwoofers ? or don't?

My experience tell me that this subwoofers subject is a critical point in the music/sound reproduction in home audio systems.

What do you think?
Ag insider logo xs@2xrauliruegas

@mke246 Great bass always brings a huge smile to my face, it is the part that makes you want to get up and dance.

Got the Genelec 7360As integrated into my system just now. With GLM adjustments they're pretty good for my needs, especially mono stuff where the minor deficiencies in one channel offset the other. I'm sure I could improve it a bit if I adjusted placement a bit, but great for now. Bass presence is massively improved across the board, even with stuff with 'average' bass, e.g. bowed string bass. Glad I stumbled into this thread and thought it over! These things are incredible.

@rauliruegas I did not say it was new and I recommend ML subs all the time. KEF does it with the Blade.  Magico does it with their Q subs. 

I am not familiar with HSU, but good for them. You are also right that digital bass management with crossovers, room control and EQ have improved the situation greatly.

I have two Model 4 subwoofers up and running. They measure great with a slowly downward sloping curve from 100 Hz down. They are 3 dB down at 20 Hz. This is without correction, with the crossover deactivated. They do not shake or vibrate at all running a 20 Hz test tone and white noise at 90 dB which is as loud as I can go before things start falling off shelves. 

@mijostyn  : Balanced force in sub's is not something new, Thiel and ML did it along other manufacturer before.

 

" I am surprised that nobody is making cylindrical subwoofers. " , not today but in the past HSU was a proffesional proponent of that design and they manufactured subs's that gone as lower as usuable 4hz frequency.

In reality, it's almost nothing new about sub's but differences in its quality design implementation and digital crossover technology that in the past never been used.

 

R.

Dear friends: Along the other 2 Harman links I posted in this page this one could be interesting for almost all of us:

 

Harman How to Listen

 

R.

 

 

Dear @mke246  : Good. That " well defined bass as low as 31hz " yes is incredible coming for 1927.

 

Good luck with your 7360's.

 

R.

After doing some research the past couple nights I'm strongly considering adding a pair of Genelec 7360s to complement my 8351Bs. I know Genelec recommends the 7370s, but I think the 109 dB SPL of the 7360s is more than enough for my needs (even 80 is pushing it for me and 90 is usually borderline painful--not sure how some of you do it!), and my room is on the smaller side. The 7370s wouldn't really even fit without some creative rearranging.

I'm not sure I fully understand the measurement side of things and whether it would be an upgrade in more than just the sub-bass with these particular monitors. I do have a couple bigger nulls in my GLM at 72 and 108Hz that the subs probably will help address.

Listened to some stuff with deeper bass the past couple days to refresh my memory, and I'd call my current setup nice and tight and reasonably full range but a little light on the deep tones you can really feel--no surprise there. Even looking at those Fats Waller organ records recorded in a church studio in Camden, NJ by Victor Records in1927, they have crisp, well-defined bass as low as 31Hz! Incredible! I think my monitors technically are capturing it, but I could see how a sub would be a more effective solution to reproduce this type of record, or any record, accurately. Would like to understand the numbers a bit better.

@mke246 : This thread exist and I started mainly to learn and understand that the main function to integrate 2 self powered subs to an audio room/system that’s used to listen MUSIC is to cleand up the whole mid/HF frequency ranges putting the main speakers IMD at minimum using a hiugh pass crossover filter and as an additional " side benefit " those subs permits no9t only to go deeper in the bass range but with a dedicated amp/drivers to that bass range be listened spot on.

Now I think that due to your personal needs in reality you don’t needs to add sub’s due too that your Genelec speakers are great self powered tri-amp excellent design where you not only can have 113 db SPL but can go down to 32hz and even usuable 28hz an according with specific model measurements your speakers at continuous 86dbs is THD is so low that maybe you can’t be aware of its levels and the low bass at that SPL is just accurated and only at over 95db SPL the speakers goes inside trouble.

Additional to all 5hose you normally listen at true near field position and different that mijostyn I don’t need to insist in subs for you. I listened your speakers and for any one it’s an " eye/ear opener ", excellent monitors truly accurated that’s main characteristic for an studio monitor.

 

 

R.

@mke246 Again it is not just the added bass performance you are looking for. It is improving the performance of your 8351Bs. 85 Hz is OK, but I would go higher at 100 Hz. Just removing turntable and record rumble from the 8351Bs will make a significant improvement.

@rauliruegas I got that crossover frequency directly from Genelec's literature. 

I use Channel D's Pure Vinyl Program for RIAA correction. It also has every EQ curve known to man. My phono stage is digitized, the signal is converted to a USB channel, sent to the computer that applies the chosen EQ curve and sends it back to the Lynx Hilo on a different USB channel. I can also record it to the hard drive in the process and do a lot of fun things like apply a pop and click filter that is very effective. 

I love Fats Waller songs but I prefer to listen to Art Tatum play. 

Genelec recommends 7370A subwoofers (around $4k each) for the 8351B but also has said in the past that 7360As (around $2.5k each) are fine if your room is on the smaller side and you listen at lower-to-moderate SPLs, which would fit my situation. Most people who implement subs with 8351Bs seem to leave the crossover frequency in the neighborhood of the default 85Hz. Still a bit on the fence--most of my music is pretty light on the sub-bass and that's a hefty investment for something I'll only get big benefits from on infrequent occasion. The 8351Bs are pretty strong at reproducing the bass on 98% of what I listen to.

Most collectors playing 78s are not going to hear the full potential of the records because their equipment is the equivalent of playing an LP on a Crosley. Bad stylus fit, bad EQ, suboptimal processing capabilities, or simply not playing an archival-quality copy. 78s will never sound like an LP-era recording, but you can make them sound like the best reissue CDs out there or better with the right equpment.

My 8351Bs are on stands on my large standing desk--sort of by necessity. They measure well in GLM software, and my room is treated with GIK panels. I mostly remaster on Sennheiser 800S headphones because I have a young child who’s usually sleeping when I have my ’free time’. I admit I haven’t put much thought into the concept of crossover frequency. The tuba and string bass on old jazz records sounds nice and tight, but I listen mostly to 78s probably limits my scope of reference when I listen to anything more modern. I’ll be researching subs and will probably pick up a pair when the time is right.

 

Dear @mke246  : I think that you are living a great first hand experiences listening to those very old recordings as that of Fats Waller. Congratulations.

 

R.

Now that I read the mijos  post I can see that the frequency is at 350hz ( I can't find it ). So, if it's at 350hz then the HP is desired to has down there but in the other side you are really listening at near field, even that the IMD is there and you can clean up. Maybe Genelec can help you to choose Genelec subs at your specific needs.

 

R.

Dear @mke246  : Good. The other parameter that we have to know with your Genelec's is at what frequency crossover those 8" woofers to the mid-range....

 

R.

@mke246 Cool Loudspeaker. I assume you have them up on stands? I saw Ain't Misbehavin 3 times. 

Think of it this way, you are getting two subwoofers to improve the performance of your Genelecs. Your woofers cross to the midrange at 320 hz. Middle C is 256 Hz. Your woofers are handling a very important chunk of the midrange. The Doppler effect inducing frequencies start at about 100 Hz and the effect increases as the frequency goes down, the worse being under 40 Hz. Genelec did a smart thing by rolling off the woofers at 32 Hz to save power and avoid the worst of the problem, but it is still there. Subwoofers used with a two way crossover will lower distortion in your Genelecs. I can't believe the processor that comes with them does not have digital bass management considering they also sell subwoofers. I am all in on  active speakers. The excellent latency and group delay performance of your speakers is due to digital processing. The easiest way to integrate subwoofers into a system is digital bass management and you are already there. When you do play modern recordings the bass will put a big smile on your face. 

I have a bunch of 78s. I can hear through to the instruments and voices and extrapolate to what the real sound must have been like, but the sound is awful. They are fun to play. Many of them have severely tortured spindle holes from changer use, talking about wow. I use an Ortofon specifically for 78's. It has a humongous stylus.  I also have a collection of popular music on 10" discs, the 45's of the day. 

One of the tragedies of my life was my Grandmother's ancient Victrola with the flowered horn. I thought I had dibs on it, but it got sold out from under me. I've never seen another that was in such good shape. 

Good points, I may think about getting a pair of Genelec 7360s in the distant future. Not something I really need but might be fun to have. I mostly work on ancient acoustical and early electrical recordings from the 1910s through 1933 or so, and the bass response on those cuts off around 100 Hz on the acousticals and maybe 50 Hz on the really well-recorded electricals. Even 100-year-old records are often surprisingly high-fidelity if restored properly. I have a few Fats Waller organ records which are very well-recorded for the 1920s with big luscious room tone, but they don’t test the monitors’ capabilities in the least. I do listen to modern music on streaming on rare occasion and remember just how great my equipment is! I’m almost always in my office in the near field restoring old records. If I have a listening party I can use a different GLM setup and tilt the monitors a bit to move the sweet spot back. Subs would be overkill for my needs, but I guess I’ll keep them in the back of my mind. It may be a while--there’s always a more pressing need like getting more custom stylii made or a rare record. Down the road, I could see squeezing them into the budget.

Dear @mke246: Well, your powered 3-way monitors are really good ( I had the opportunity to listen it. ) specially at near field position.

The weakness ( if any ) is when you have a greater room and don't listen at near field position where the bass range at higher SPL just distorts, nothing is perfect and in my case even that normally I listen at near field position my room is to big and I listened to evry kind of MUSIC with low bass content. I don't know how you considere Organ instrument as an acoustic o0ne or not but not only the organ scores but what mijos posted about the venue breaths.

I don't know the kind of room you have and your seat position but maybe you are acandidate to integrate a pair of subs using only low-pass filter, using the subs as a low bass reinforcement crossover30hz-40hz 8th order filter shape. Just thinking " loud "..

 

R.

I'm happy with my Genelec 8351Bs that reproduce accurately down to 32 Hz with no subwoofer. Most of what I listen to, i.e. recordings of acoustical instruments and ancient 78 RPM records, isn't recorded below that, anyway, so I don't care. It would be nice to have one, but the amount of expense and trouble I'd have to go to to get something appropriate would be far disproportionate to the amount of enjoyment I'd get out of hearing the handful of recordings I listen to with crazy-low notes. I have better things to worry about.

@rauliruegas is right in many ways with a few caveats. 

In a normal point source system two subwoofers is fine and more does not add much. Line source systems require a driver every 4-5 feet along a wall to form a line source subwoofer to match the main speakers.

I would not bother with subwoofer drivers smaller than 12". 10" drivers are fine if you use two of them per enclosure. Most big point source systems require two 15" subwoofers. The smaller the driver the greater the distortion levels at a given volume.

Blending the subwoofers into the main speakers using second through 4th order slopes is appropriate for all subwoofers except a small number of truly excellent units. Subwoofer enclosures are extremely hard to make. Most of them are musical instruments and have a particular sound. If you use a steep slope with these subwoofers the cross is very noticeable. Turn the volume up and place your hand on the sub enclosure. If you feel any vibration you have a musical instrument. Subwoofers that have no sound of their own (do not vibrate at all) can be run higher up using very steep slopes 8-10th order (digital only) as there is little sonic difference between the subs and the main speakers at the crossover point. Here the important factor is keeping the sub out of the midrange where you will hear it. Subs are integrated correctly when you can't tell they are there. Using a low pass filter only on subwoofers is a sad proposition. Easily 1/2 the benefit of using a sub is cleaning up the midrange of the main speakers. You have to use a high pass filter on the main speakers to do this. It is not done because of the added expense of electronics and cables. 

I believe all subwoofer systems should run down to 18 Hz. Music does not go that low but venue clues do. Large venues breath at very low frequencies. With some live recordings you can feel the venue. Subwoofers should be felt more than heard. This is the difference between a live and reproduced performance. Proper subwoofers give you the feeling and excitement of a live performance. 

In my mind there is no difference in the requirements of a theater vs music system. A great music system will sound just fine in theater mode and is quite capable of rattling your teeth.

These are some important concepts to keep in mind when buying subs. Balanced force design. Some of the vibration you feel is the enclosure shaking in opposing response to cone movement. Placing a driver at opposite ends of the enclosure cancels out these forces lowering the musical instrument factor. Smaller enclosures are better because they are easier to control lowering the musical instrument factor, but they will require more power and possibly EQ. A box is the worst shape for a subwoofer. The best shape would be a sphere, but this is impossible to make. The next best shape is a cylinder. Cylinders have inherently stiff walls and are less prone to resonance than flat walls. Cylinders are relatively easy to make and I am surprised that nobody is making cylindrical subwoofers. Open baffle subwoofers are IMHO a silly concept and a florid waste of power. Why some people think they are great is more an indication of how poor many enclosed subwoofers are. There are many excellent subwoofer drivers out there. Dayton makes a Reference sub driver for any situation and I do not see how you can do any better. DIY by all means. Think big pipe with a driver in each end. You can get aluminum pipe in almost any dimension, cap the ends, drivers, binding posts and cleverness. 

Subwoofer drivers take a beating and even the best ones fail on occasion. It is not a bad idea to keep a spare driver handy. The drivers evolve and it is unlikely you will be able to get the same driver after 10 years. Without a spare you will have to replace all of them. 

Dear friends: from my last sub changes I confirm that that doppler developed characterisc in woofer main speakers must be should be at absolute minimum.

The issue is that the bass range is all about MUSIC room/system quality level reproduction and the bass rage must be perfectly blended inside the bass range. This is high mid-bass, mid-bass, low mid-bass, low bass and deep bass.

That blend must permit that we be aware of eacg bass frequency range with out a bass frequency range " leader " or " leaders " and all those is the true challenge we have with the subwoofer room/system integration.

That bass frequency ranges blend will gives me the best MUSIC rythm ever and the perception of dimensional MUSIC presentation where each track performs in its each territory that’s our room seat position.

 

With out all those we can’t really have true MUSIC enjoyment and only " something " that we like it..

Not an easy task that bass range frecuencies blend because it’s as complex as a speaker design where the designer needs not only to choose the rigth drivers but the rigth crossover frequency for each driver and the crossover filter shape that permits a seamless blend that’s what makes the differences between a good speaker and a very good or excelent speakers.

Here mijostyn  looks as he knows about and maybe could share his point of views.

 

R.

Well, Velodyne makes the blend at crossover frequency with a second order filter shape and latter on pass through fourt order and finished at 48db per octave in my HGS and the Velodyne HP is a first order filter (6db. ).

The name of the game is that blend at 12db per octave along the 6db per octave that in my case is not made by the Velodyne but at the input of my Levinson monoblocks..

 

R.

" Two subwoofers, at opposing wall midpoints, performs very nearly as well as four at the midpoints and gives a much better LF factor. "

 

That’s the Harman conclusion. Now, if we are using our room/system mainly to listen MUSIC where is the bass range we need be reproduced by subwoofers?

Mainly from around 50hz-60hz and down at least to 16hz but 80%-90% of our daily reproduced MUSIC bass range belongs from 60hz/70hz to 30hz and for me this is the main ( other than put at minimum the Doppler effect/IMD ) desired dedicated drivers to bass reproduction and here the phase subs control is way critical. Yes some kind of instruments MUSIC reproduction needs that the subs can works fine from 25hz to 16hz, fine means with absolute aplomb. My Velodyne has usuable 10hz frequency but not so important.

In my latest phase experienced tests I been totally sure about because the overall reproduced sound over all the system frequency range was and is improved in its quality levels as ever before the phase subs change and was only this parameter the one I touched in the subs : same volume, same crossover point, same everything including the subs positions, nothing then but the phase.

 

Other critical and way important issue when we are integrating subwoofers in our MUSIC system is to have a " rigth " blend " between the sub’s crossover point and the main woofers crossover point.

It has to works exactly as speakers designers do it with his speakers where they choose the rigth crossover frequency of the different filters ( HP, LP, BP ) using normally between first and third order for those filters according each frequency range driver to BLEND . No one use 6 or eigth order filters because the issue is to BLEND and not separates the frequency ranges. Then, this BLEND along the Phase are crucial.

 

R.

Dear friends : In this subs issues we have to follow the Physics rules. Here a room mode calculator:

 

Room Mode Calculator_0.xls (live.com)

 

and here why at one seat position 2 subwoofers are good enough to listen MUSIC, we don't need 4 but we can use those 3-4 additional in HT but not need it for MUSIC only:

Microsoft Word - whitepaper10.doc (harman.com)

 

R.

 

@mijostyn  : Sorry but your post has no meaning for me or I made a poor explanation in my other post.

 

R.

@rauliruegas I never said that! From the second I first fired them up I knew Sub model 3 was deficient, but I did learn a lot from building them. Sometimes you have to know what does not work to know what might work. Sub model 4 was inspired by Magico's Q subs, except I took it several steps further. 

The most efficient location for subwoofers is in a corner followed by up against a wall, 6 to 9 dB more efficient. The problem with these locations is you can not integrate the subs properly with strictly analog equipment. It requires digital bass management.  You are putting the subs where they sound best. I am putting the subs where they work best then making them sound even better.

My subs are not transmission lines. They are a balanced force, acoustic suspension (sealed) design with resonance free (and I mean totally resonance free) enclosures. The walls are 1 7/16" thick. The 10 sides are only 4" wide and they are arranged in a cylinder, an inherently very stiff structure. They are much smaller and lighter than the Magicos making them more practical in all situations. They weigh just over 100 LB each. There will be four of them eventually forming an 8 driver linear array. They are 2 dB down at 20 Hz without any processing. @skoss heard them yesterday. You might ask what he experienced. The picture is up on my system page. 

The sound is not where I want it yet. The system is now dead flat from 20 Hz to 12 kHz. I can boost the subs by adjusting their volume relative to the stats, but this makes the bass too warm. The sound is also on the bright side, again because to is corrected to flat. There will be a EQ program in the DEQX and it is supposed to be in the next upgrade. That will allow me to program the amplitude curve to my taste, bass increasing 3 dB/oct below 100 Hz and a shallow drop from 1000 Hz so that 20 kHz is down 6 -12 dB. 

Dear @secretguy  : " And in the wrong category. "

Could be but when started this thread I decided in that way. Not many analog lovers were using subs in their systems like today times. In those old times and through this thread several gentlemans ( including me ) learned a lot about this subs crucial/vital audio subject.

R.

Dear @mijostyn  : " One minute you think you have it sounding great, the next minute not so much. "

More or less is what happened when started to test it that nigth but from yesterday till today the romm/system reproduced sound is just nothing less than sublime.

 

Last time I seen your virtual systwem the subs were directly seated in the floor, for me not the best any sub position. The new cilindrical boxes looks fine and similar to a transmision line subs that I listened several years ago. Have good luck with.

 

R.

 

@rauliruegas It is phase and time. The Australians call it " launch time"  The sub has to be in phase with the main speakers and the signal from the main speakers and subwoofer have to reach your ears at exactly the same time. Changing only the phase angle of the subwoofer is going to change the amplitude response of the system is unpredictable ways. The system may sound better or worse depending on taste and even the music you are playing. It can drive you crazy. One minute you think you have it sounding great, the next minute not so much.

@lewm  Many subs have continuously variable phase angle over 180 degrees, but without the ability to match arrival times the phase angle control is a real double edged sword. Once matched in time and phase everything sounds great. You REALLY need to try subwoofers with your SLs. Get an inexpensive MiniDSP  crossover to start. This will give you a good idea what the advantages are, then you can get a more elaborate unit down the road. Benchmark Media Systems uses a MiniDSP SHD studio and two of their own DACs.

I just finished the first pair of model 4 subwoofer. I'll be putting a picture on my system page. 

Raul, I assume you’re referring to the electrical phase of the signal delivered to your subwoofers with reference to the electrical phase of the signal delivered to your main speakers. This is known to make a difference. But usually one can only alter the phase relationships by 180 degrees, by reversing leads or inserting a phase switch. Are you able to test differences in phase that are >180 or <180 degrees but more than zero degrees? If so, how?

Dear friends: I started this thread almo9st 20 years ago but things are that as many other audiophiles I followed learning not only in this subs issue but in the audio world genral subjects.

 

Well, in the last 2 years I made it several chnages/up-dates/up-grade to my room/system and mainly to my speakers crossover parts.

So and thank's to a thread dialogue in Agon where I 'm participating last nigth I decided to try different changes in my subwoofers PHASE that's a subject that not only in this thread but in no other thread or audio forum never read in deep the critical importance of Phase in the subs to stay sure that's room/speakers integration is " optimal ".

Started listening to Original Motion Pictures  CDs source with MUSIC as Day After Tomorrow, Gladiator, Thin Red ine and the like. Almost all goes deep in the bass through synthesisers. During my late nigth session I left the PHASE at the best position my ears told me and I gone to sleep with some doubt about.

So, early this morning I come back to my system to continue testing PHASE in the subs and this time with acoustic instruments in several LPs I own and used mainly the Telarc 1812 recording that comes with several kind of bass at diferent frequency bass ranges and my last nigth doubt came out: the choosed Phase was wrong and when finally my analog Phase tests session I achieved a quality level I was not prepared to attain, it was something unexpected and the best it happens to me in many ytears with my audio system.

 

That's why I urge all of you that already own subs in your systems to " play " seriously with the Phase control in your subs and if you already do it then try it again to confirm is ok for you.

Patience is only what we need but the rewards are huge on this Phase critical subject.

I never imagined its crucial importance.

My findings where confirmed in an Agon thread by a true Agoner expert in that and other audio subjects as is : @deep_333  ..

R.

 

Post removed 
Hi Tim the low level dynamics are from the use of auto former or transformer volume control that's the key component . Check out Intact audio . No loudness contour . The one thing I have is a great digital front end   
Hi Doc,

     I believe you live in a Manhattan postage stamp so lack of space and the need to listen at lower volumes are issues.  I hear the penthouse at Trump Towers may be available soon. Just something to consider if you want more room, fewer neighbors and solid gold toilets.

      I now understand you use your DSPeaker for 600 hz and below system wide.  The upper range of this (specifically 50 -600 hz) is reproduced by your main Ohm Walsh speakers and not your subs; you run your subs in stereo with the front 2 subs handling 60 hz and lower and the rear 2 subs handling 45 hz and lower.  I think you're aware that there is some overlap with both your front 2 subs and your main speakers reproducing frequencies between 50-60 hz.  But your DSPeaker likely adjusts output in this small range to smooth out response.  Your clarification now makes your system a lot more sensible to me.  

     My goal is mainly to learn how your system functions and not to criticize a configuration that obviously works so well for you.  I know it's not easy to construct a system that sounds good at lower volumes.  It's been well known for decades that human perceived loudness of very low and very high frequencies, in comparison to mid-range frequencies, decreases as volume is decreased.  This was the reason some older audio components (1980s to 90s) had 'loudness' buttons and controls that boosted these frequencies to compensate.

     Perhaps the reason your system sounds so good to you at lower volumes is because your DSPeaker incorporates a 'loudness countour' that is boosting the lowest and highest frequencies relative to the mid-range frequencies as you lower the overall volume of your system.  This is only speculation on my part but I think it's a reasonable assumption given your results utilizing this DSP tool.

Tim
Hi Tim the problem I have is I am limited on space to play with optimum sub placement . I use my subs in stereo the front subs are set to 60hrz and the rears are set to 45hrz . The DSPeaker makes this arrangement work well . the DSP has a bypass mode so you can hear the difference the correction is doing . I have had the DSP for 3 years running 2 stereo subs with great success adding the rear subs improved the whole system . As for the DSP being transparent I have been tweeking both my digital and analog front ends and I can discern the changes . The DSPeaker and my custom Bent Audio / Dave Slagle AVC volume control pre amp makes low volume listening sublime .Tim if you want to understand the DSPeaker there is much info on it              
Hi Doc,

     I like your commitment to all out sound quality by using your tube VTL 100s for both 2 channel and HT.  I just have a few questions:

1. Have you tried lowering the sub crossover frequency  closer to the 50 hz lower frequency cutoff on your amps?

 DSPeaker room correction for 500 hz  and down seems somewhat high and broad to me.  I consider 500 hz to be in the lower mid-range spectrum rather than the bass spectrum.  

2. Have you tried running your system with all room correction units removed?

I think you'll find your system's bass response will be very good without it.  I would recommend setting each of your sub's crossover setting initially at 60 hz and then experimenting with even lower settings of 50 or even 40 hz.  A setting of 50 hz may not be good in your room due to your room having a frequency bump @  50 hz.  The downsize of this approach is that the level and cutoff freq. would need to be set individually for each sub.  But this should only need to be done once at the precise setup/calibration stage.

Thanks,
  Tim
Hi Tim I use the VTL 100 amps for HT and 2 channel music . as for tube life I am using 2 KT120 tubes in each amp if they wear out so be it . There is plenty more of them available . I use the DSPeaker as a room correction for 500hrz and down for the main speaker and all 4 subs . This device works by using a microphone to measure the room response from the listening area then it runs a series of tones across the L/f range and applies a correction . I have frequency bump @  50hrz and the DSPeaker corrects that . The biggest improvement with adding the 2 extra subs is that the bass response all through out the room is much more even and the tonal quality is better. RC      
Hi enginedr1960,

     It sounds like you have a combo system, as I do, used for both music and HT.  I was a bit surprised you use VTL 100 mono-block amps in your system.  I would imagine they're great for music but less than ideal for HT since tube wear is increased.  Or, do you have your system configured to utilize separate solid-state amps for HT duties.  Could you clarify this?

     
     I understand how your Outlaw pre-pro is used for decoding surround sound codecs for HT.  But I'm not certain how you utilize the DSPeaker antimode 2.0 and exactly what it does.  Could you explain in more detail how your DSP controlled stereo bass works?  

     I've been trying to spread the word on distributed bass arrays using 4 subs here on Audiogon ever since I personally discovered how well it has improved bass reproduction in my system.  After a lot of research, I intellectually understand the acoustical physics and the theories on how and why it works.  But I still think there is no substitute for auditioning a good DBA in person for appreciating how impressively it reproduces bass in any room without the use of mics, room analyzing/room correcting software, equalizers or room treatments.  

     Based on the large number of posts I've read from members who seem to think their system bass response needs can be solved if they just get the right brand or model of sub, it's fairly obvious that many are unaware of the DBA concept.
     You're actually one of the first Audiogon members I've encountered thus far that also utilizes  a DBA.  I'm glad we're now aware we both use slightly different DBAs and can share experiences and information with each other.

Thanks,
  Tim 

Hi Tim getting back to the best bass I have heard in my system . I have been using DSP controlled stereo bass for three years with great results . After hearing a dynamic system with 4 subs I was inspired to try it myself .My system is centered on a DSPeaker anitimode 2.0 the DSPeaker only has I analog input I paired it up with a DIY 4 input 2 output Bent audio TAP x passive autoformer volume control . the DSP is inserted in a in and out loop . For amps I am using a pair of modified VTL 100 mono blocks using 2 KT-120 tubes ea. puts out about 75 watts . My speakers are Ohm Walsh 2.2000 in custom cabinets that are placed on top of the REL Q201e subs . The power amps have caps in the signal lines to cut the L/F off @  50 hrz . the subs take over from there . I use a analog as well as a digital front end . And for movie night i have a Outlaw Pre Pro that is another source and of course more amps and speakers . My system is far from simple .The only simple thing is it can be turned on with one button that was so that my technically bankrupt wife could use it . I had to design this system around the limited space I have . After adding 2 more subs at the back of the room the bass response has evened out much more then with the stereo subs . Works like active room treatments. All I can say on good recording I give myself goose bumps and that's with both digital and analog . And Raul you may piss off some people but you make us think and that's not bad its good science .RC              

Hi enginedr1960,

     I agree with you completely, there really are many ways to achieve great sound.  I'm very impressed with the home-made distributed bass array system you created with your 4 Rel q201e compact subs and other components.

     I've been assuming you have no need for your Bent passive Dave Slagle autoformer volume control and Minidsp 2 x 4 simply because I use no such tools in my system and it functions beautifully.  I admit my comments were made without a complete understanding of these products and how you utilize them in your system.
     I took your suggestion and did some research on the Bent passive volume control, the TAP system and the Dave Slagle Singleformer modules.  This seems to me to be a seriously high quality product/system and, if this is any indication, you obviously choose your system components carefully.  I believe you use this to control the volume and balance of your 2 front Rel subs via an optional remote.   I believe you use the Minidsp 2 x 4 units to control your 2 rear subs and perhaps even some room correction..

     As you can see from the above, I only have a partial understanding of exactly how you use these products in your custom DBA  system.

     However, I'm sincerely interested in learning more about how you utilize these products in your system.  I think sharing exactly how our DBS systems are configured would be a good way to learn from each other and could be mutually beneficial.  I hope you agree but please let me know if you don't.

     Okay, I'll go first.  I think you'll find my system is a bit simpler than yours since I made a conscious effort to simplify my system about 2 yrs ago and I don't use any additional components:

     The center of my system is the Oppo-105 Bluray player. Once I was familiar with this unit's extensive versatility and excellent quality, I began to simplify.  I removed my beloved VTL 2.5 tube preamp (with NOS Mullard tubes)  because 2-ch music sounded just as sweet and dimensional using the Oppo alone as a preamp due to its excellent audio section.  I then removed my Parasound AV-2500 surround processor because the Oppo's built in Dolby 5.1 decoder performed just as well.  All channel outputs are run directly into  4 class D amps (the front L+R mains via XLR cables and all others via RCA).  

     I bought the audio Kinesis 4 sub Debra distributed bass array system a few months after the Oppo.  I run an RCA cable (with a single RCA connector on one end and dual RCA connectors on the other end)   from the single sub output on the Oppo to the L+R inputs on the Debra's supplied 1,000 watt class A/B sub amp.

      This amp is a mono amp so all 4 4 ohm subs operate in mono mode in my system.  I found I cannot perceive any differences between mono and stereo bass until the bass crossover frequency is set unusually high ( above about 150 hertz).
      The supplied sub amp has 'A' and 'B' sets of speaker outputs.  I have the front 2 subs connected in parallel to the 'A' terminals and the rear 2 subs connected in parallel to the 'B' terminals.

     The Oppo has a configuration menu that allows for the on-screen setup of the following:

Speaker Size- Each speaker is entered as either 'Small' or 'Large'. All 'Small" designated speakers have their bass augmented from the subs while all designated as 'Large' receive no bass augmentation.

 Speaker Level Matching- This allows the matching of each channel's relative volume or setting to other preferred levels.  A system generated tone is played and the user cycles through each channel. The Speaker Size (large or small), speaker volume (from -10.00 db to +10.00 db in increments of .5 db), and distance from the listening position (from 0 to 60 ft in .25 ft increments for delays) are all set in this section.
    This Speaker Level Matching section also includes settings for the relative volume of the bass in this section.  There is also a volume control on the Debra amp that can be manually adjusted for fine tuning the desired bass level of the 4 subs. 

Sub crossover frequency- This allows the setting of a frequency (from 40 to 250 hertz in increments of 10 hertz) at which all bass frequencies at or below this hertz number are sent to the subs. I usually select a 40 hertz cutoff for 2-ch music and ia bit higher for HT.

     After completing the rather extensive progressive setup procedure for the precise  positioning of each sub, the above describes the total extent of system configuration required.  I use absolutely no room treatments, microphones, sound meters, room analyzing/correcting software, DSP, tone controls or equalizers.  
     The system Master Volume is controlled through the Oppo's internal 32 bit digital volume control that is accessible either through the Oppo's front panel or supplied remote. I doubt this volume control is as precise as the 1 db changes  the Bent volume control is capable of but it is capable of small changes in volume.  
    I hope this helped you understand how relatively simply my system functions.  
     Please let me know your thoughts and let me know in more detail how your system functions.

   Thanks,
    Tim 
 
Hi Tim great thing about this hobby is there are many ways to achieve great sound . I chose my components very carefully based on my preferences . I do my research and know how to read in between the lines . I am a engine builder by trade I take the same approach in building a audio system as a high performance engine . I apply the system to the room . The Bent passive Dave Slagle autoformer volume control is a great component . The volume control in most audio systems is the weak link . Do some web research on transformer and autoformer volume controls . I have a great sounding system at the lower volume range then all the others I have heard . Remember you cant fix it unless you know how it works !     
Thanks, Noble. I did find the Romeyn website for the Debra, by searching on "Audiokinesis Debra", oddly. As you note, they are similar in price and very similar in composition.  So this begs the question, why are two different and so similar products co-existing?  Do you have a feel for the audible differences between the two?  And, a question I will address to Duke as well, does the set-up provide for a hi-pass filter to feed the amplifier that is driving the main speakers?

Thanks  R I have been thinking that myself . I need to change the value of the amps signal line caps . I will give it a try .
Dear @enginedr1960: I think that you can have even better results if your monitor hi-pass changes from 50hz to 80hz. You can do it listen it and decide about. It's only an alternative to test it.


regards and enjoy the music,
R.
Hi lewm,

     I already knew the 845s are one of the most efficient Sound Labs ever made (about 89 db).  It sounds like your mods made them even more efficient and a good match with your OTL tube amp.

     I was just listing all the benefits I thought going to a DBA would have in your situation.  I now understand you don't really need to decrease the demand on your OTL.  You're more interested in a DBA to get a more full-range frequency balance and increase bass definition.

     I can confirm that a Debra or Swarm DBA will give your system high quality bass that is capable of blending seamlessly with your Sound Labs while it's also able to reproduce deep,powerful and impactful bass when the content calls for it.

     Just to clarify, Duke sells the Audio Kinesis Swarm and James Romeyn Audio LLC.  in Utah sells the Debra system. Here's a link to the Debra system:
http://jamesromeyn.com/old-pages/home-audio-gear/dsa-1-0-distributed-subwoofer-array-5-pieces-4k-usd...


 They're both basically the same 4 sub DBA, with small differences mainly in the subs' construction.  James licenses the rights to sell it from his friend Duke.   They both come with the same 1,000 watt class A/B sub amp, are both rated accurate down to 20 hertz, about the same system price and share the exact same setup procedure.  Either system will deliver excellent bass response that is very evenly dispersed due to the significant reduction in bass standing waves in your room.

     I didn,t know you bought your Sound Labs from Duke.  He'll be able to give you good advice on how well the Swarm would integrate with your 845s.

  Good idea to give him a call,

                Tim   

     
Tim (Noble100)
We are on the same page.  However, I would be doing it for the gain in bass definition and overall frequency balance, more than to relieve my primary amplifiers of any stress.  The 845PX's normally use a 6db/octave passive crossover in front of two different audio step-up transformers that receive, respectively, bass and treble frequencies after the x-over.  This configuration, however, creates a nasty impedance dip at mid-frequencies, in addition to sucking energy across the resistor used in the hi-pass filter.  2-3 years ago, I replaced the treble transformer with a very high quality full range transformer, which enable me to ditch the RC network that creates the hi-pass; I still use an inductor in front of the original SL bass transformer, albeit I replaced the OEM inductor with an 12-ga air core type.  This mod hugely improved the efficiency of the speaker; I daresay it could be driven by less than 50W to very loud sound pressures.  My OTLs can do about 100W, and they are loafing at all times. It also dramatically improved dynamics.  I measured impedance v frequency across the audio range, after the mod, and I see 20 ohms or greater from about 100 Hz to 5kHz. Below 100 Hz, impedance is rising.  Above 5kHz, it falls to about 6-8 ohms at 10 Khz. This is an ideal match for an OTL.

I did mention that someone here had pointed out that two of the 4 woofers could go behind the panels.  Sorry for not remembering to credit you with that insight.  I've known Duke for a long time; I bought my 845s from him.  I will give him a call soon. On his website today, I do see the Swarm, but I don't see the Debra system.  I'll look again.
Hi enginedr1960,

      I understand the frustrations and compromises involved with the infamous and insideous WAF.
       I followed the  elaborate progressive sub setup procedure  rather strictly.  I took my time determining  exactly where the bass sounded best and clearly noticed the bass sounded the most natural to me located at least a about a foot or more away from room corners; the corner positions definitely reinforced  the bass response, causing bass peaks and were sub position sites I knew should be avoided.
      My goal was to find the precise locations in my room where the bass just sounded natural and right and I avoided all locations where the bass was over or under emphasized.  I think this is the reason that none of my 4 subs are located at one of my room's 4 corners.

    However, I understand your significant other may prefer the subs be tucked way in the corners of your room, the exact locations that are most likely to result in the presence of bass peaks at certain spots in your room where bass response is obviously exaggerated. 

    Just a word of warning, none of the subs should be placed squarely in a corner unless you determine that is where it sounds best, which is unlikely.  If you must place a sub near a corner,  it's best to position it at least a few inches away from the corner's center along one wall or the other.

   It seems like you've become too accustomed to using your DSPeak and 2 x 4 to even consider not using them.   I still believe there's no need for these tools, or even your Bent Audio volume control,  in a properly setup DBA system.  However, I may not completely understand why you consider these products so indispensable.

Thanks,
 Tim

Hi Noble I have my own placement restraints as i live in a Manhattan apt. I spent much time configuring my system for getting the best sound while meeting the dreaded WAF . To save floor space my Ohm Walsh 2.2000 speakers are in short cabinets that sit on top of the subs the height is set to put the tweeters at ear level . My speakers are now sealed and don't work well at 32 hertz . I installed signal line caps in my tube amps to cut them off @  50 hertz . I upgraded the amp for the two front subs with a Crown XLS2502 and set the crossover to 60 hetrz . My DSPeaker is paired with a custom DIY built Bent Audio auto former volume control . Yes I have and use tone controls in the digital domain it is transparent . As for the Mini DSP 2x4 I am using it to control the rear subs only it is very flexible .I have the two rear subs in the rear corners out of sight . I read the instructions for the Debra system and am trying the polarity invert . I  have been using DSP controlled stereo subs for about 3 years and after hearing a distributed bass system I was convinced . I am loving this arrangement . Thank you for the advice .