Frantz,
As I already own the Behringer DCX-2496, the Behringer ECM-8000 and EMU sound card , and have read the Geddes threads your comment Resulting in my personal case in the best bass I have heard is really newsworthy. Can you give me more details about your implementation?
Do you consider that the result you got was better than a single IB sub?
Hi
It is not secret here that I am a big fan of multi-subs and of the Geddes approach in particular. Subwoofers can be used in multiple. One can for example stack subwoofers and the results are usually better than one subs, simply because of the headroom it provides… more “woofing” surface, then lower distortion, higher SPL, well more headroom to accommodate peaks and with more bass more information within the sounds cape… Low bass seems to carry lot of the size cues of any venue... Even those that are artificially created … This out of the way … one thing that I got to understand with subwoofers was that getting a flat response at the listening position did not necessarily product a satisfying bass... it never seem to e real or realistic … I got to understand that it was important to have a smooth bass response within the listening volume, that is in the room where one listen to music. I am not yet entirely clear about this. I however have come to believe that what we hear in the bass more so than the rest of the spectrum is dependent on the bass response at multiple points in the room. There has to be a volume, the larger the better within which the bass is smooth, not necessarily flat (likely impossibility) but smooth response. This is a speculation, one that I cannot yet substantiate but my experience and likely that of those who have experienced multiple subs could concur (whether the Harman or the Geddes way).
I had some references. I am very familiar with the superlative low bass of Genesis speakers and like the dipole bass of the Magnepan in a room, I could reach below 25 Hz with the Maggies with power and definition but something was always amiss…I did try the Maggies with Sunfire subs and liked what I heard but still was missing something that I hear in large venues … Out went the Sunfire, I went for a while without subs but was constantly reminded of what true powerful low bass brought to the music. An organ, Bass drums or a Tympani or even a synth in venues have a way of energizing the space to let us know with our eyes close its dimensions and even shape … Some of us refer to this as pressurizing, I think it is much more. I think that my first post on the AVS Forum was about bas and subwoofers… I learn quite a bit from this forum amongst it references to the Harman papers on multiple subs and later learn about Earl Geddes though a discussion he had on mono versus stereo bass on a thread about DTS or such … Thus I embarked about 3 years ago after having discovered the Harman and Geddes methods into subwoofers in a 2-ch system. I had some starting points, I knew what to expect from the Magnepan in term of low bass and what a sub brought to them, I have heard some really superb performers in the low bass (in different rooms ) mind you, I had previously embarked in treating my rooms with Tube Traps and some Tube traps clones.. I had a good sounding system in the bass reaching with room help 25 Hz with real power and articulation …
It is a weird thing to ask an audiophile not to go symmetrical on anything … Especially on speakers … The idea of putting three subs in different positions is almost anathema to us but I took myself on and tried one subwoofer in the right corner , room was concrete. Sub was paradigm .. In the corner it did go as low as 15 Hz with a weird response , 15 Hz was much higher in level than 40 Hz despite the Maggies and the subs playing. At the listening position I now had a very strange response of elevated low bass and depressed bass *(40 to 100 Hz). Weird sound: Instruments starts light and become heavier as they approach the lower bass, pleasurable for a while but utterly wrong … I added the second sub with phase at O and same low pass crossover frequency 40 Hz as the one in the corner .. Things went better in the region between 40 and 60 but now I had a lightweight mid bass 80 to 150 approximately …. Played with the sub crossover using a slightly higher crossover at 65 Hz and suddenly things started falling in place without touching the controls in the corner sub. The response became even better when I put the phase control on the2nd sub a little over a quarter of the know b=course … I took measurements but they were lost with the PC in the room some time ago along with the subs and many other things… The third sub brought the response to be flatter in a much larger area.> I would say a volume the size of sofa and about 6 feet high. This of course after fiddling with the phase , level but not crossover settings of the second and firs sub Crossover frequency in the 3rd sub was the same 65 but phase control was past the middle of the control range… Good response going down to 16 Hz with reasonable smoothness but some strange peaks in the range at 40 70 and some other frequencies. I used the system like that. Response was OK, Subjectively the whole was much better than what I was getting from the Magnepan with the visceral impact of cones but the realism of dipole bass … Later I introduced the Behringer and used within the beginning disappointing results, took me a while to replicate what I was getting with the subs alone. I started getting more efficient in the use of REW and noticed the delay function on the Behringer …Took me a while during which I used the Behringer to experiment but listened with the subs alone .. Until I read the results of Markus Mehlau in the DIY forum .. I went back to the Behringer with almost an attitude and got it to do what I wanted, not before I had to get a Pro to consumer level converter , which was being recommended by the people on the DIY Audio forum. I would say getting the best results from the Behringer tock me a good 3 months .. And the results? Simply spectacular ..I was getting the kind of bass one gets in real life.. You know the brutal “in the chest” you hear in real music but it wasn’t at the cost of subtlety. Chamber music to repeat myself became more articulate with a clear understanding of the recording venue. While I could not get to what the Genesis 1 would do in the low bas =in term of scale and power, I would get in what any speaker not being the genesis of most any speaker you care to name this side of the Gen 1 or Gen II. The room was pressurized ,, you know the bass would pump in your chest.. When I played the Ravel Bolero on Telarc or particularly the Reference Recording one the finale came with the drums in the room … Things like Dafos took on an almost scary nature and yet I started to notice a more relaxed midrange and a clearer treble.. Difficult to really explain but once the bass is that kind of good you’ll understand. How does this bass in my (former) own room compares to an IB? Different .. The bass from IBs is different from anything I’ve heard, it is “drier” and the power is almost addictive. It seems at first less powerful and less present than with a regular subs or subs. IT is for the lack of word cleaner. You simply hear bass with a lot of power but no overhang , no one note bas in other words better than what I did hear from mine .. The IB was alone and it wasn’t as smooth but truly preferable. I was embarking on an IB for my 2-ch but things went down with the kind of force no subs can emulate .. I will build one in the future it is not possible in my current place ..
I did take measurements and they confirmed what I heard. I have the measurements on a laptop drive I retrieved from the rubbles. I haven’t been able to retrieve any of these files but keep the HDD just in case I find a way to do it. Some companies do it but for a serious price and the data on this laptop aren’t really worth it … I don’t want to appear to say that it is easy, it is not , It took me a long time.. I read and read, PM and aksed questions. I did go to the AVS subwoofer forum , lot of info, DIY Audio Ditto and the Culto fothe Infinetely Baffled , good info , extremelyhelpful by the way if one does want to build an IB.. I would say the attitude is toward objectivism and measurements at the cult few mentions of black background there …
Long post but this is to give you an idea of what the Geddes and likely Harman method brings to the plate. I am almost certain it is impossible to obtain this without subs emphasis on plural, regardless of the bass capacity of the mains. I don’t care how low a speaker goes by itself: For best integration in most rooms.. One must use multiple subs.
...And BEST is to live in the NOW, and not in the past or future conceptions. Some' like that anyway. 
