Darkmobius - We should start a support group together! My setup originally had the preamp outputs feeding SET amps, and running full range to the satellite speakers. The sub signal was summed mono, with a 4th order low-pass filter. I heard the satellite and sub signals overlapping too much, so now am using a high-pass filter to the satellites. This definitely cleans up the overlap. In the article Raul posted, the author advocates 1st order filters. I may try this in the future, since with horns we are deep into phase and time alignment issues. But then I'm back to freq overlap issues. So, how to find the proper balance?????
scott |
Very interesting discussion. In the past month, my first experience integrating a sub-woofer into my system had some unexpected results. My Edgar Seismic Sub arrived about a month ago, before the Edgarhorn speakers. The Seismic is a 6' tall folded horn driven by a 18" JBL 2440. While waiting for the Edgarhorns, I practiced integrating the sub with my Alon Circes, which are rated flat ~ 20 Hz. Rather than bass reinforcement, the most noticable difference with the sub and Alons was improvement in sense of accoustic space. There were more cues to the physical size of the recording. For example, it was clearer to sense an intimate jazz venue from a symphony hall from a recording studio. The next difference was improvement in the clarity of mid and high frequencies. On the other hand, it was alot of work finding proper balance between sub bass level and overlap with the Circe, especially since there was no low-pass option on the dedicated sub x-over to roll-off the Circe's output level. I ended up using the lowest crossover setting of 30 Hz, and fairly low level. Now, with the Circes replaced by the Edgarhorns, it is completely different. The horns roll off at 80 Hz, and I'm still trying to find the proper x-over point and level and placement. Placement is limited due to the physical size of the horn sub. It is almost, but not all the way, into a corner. Also, the x-over point is much higher and more audible, ~ 70 Hz. The slope is 24 dB/octave, so I may need to go still lower. And still working on level matching, especially since Bruce recommends up to 6dB boost ~ 30Hz. So many variables to lock down. As for proper stereo reproduction, I am not prepared to commit to a second Seismic Sub, since my room size is only 15' x 18'. Anyway, my experience taught me that the benefit of the sub is NOT so much bass reinforcement, as spatial and clarity up higher. Thanks for a good thread. |
Raul -
***Btw, I choose ( too ) 1st order filter for the high-pass on my system. This high-pass filter is inside of my 20.6s. It work for me.***
I will first try placing caps before my amp inputs, for easy changes. I like the idea of permanently locating the filter inside the amp.
***I think there are no rules here other than: test, test and more tests***
My satellites go to ~80Hz. My concern is that a 1st order crossover accomplishes too little for my goals:
1) minimize overlap between sub and sats (only 6dB down at 40Hz and 12dB down at 20Hz!!!)
2) eliminate LF signal from amp, for less distortion
I will test, test, and test. How did you deal with the overlap?
scott |
Darkmoebius - Like you, I am on the steep part of the learning curve. Here is an article about sub integration I found interesting: Getting the bass rightUnlike Terry, the author advocates many reasons for corner placement of subs, to cancel nodes. In any case, you might enjoy the article. Let me know your results if you try placing the subs outside your mains. scott |
Doug, a small cap can be installed at the input to your amp as a high-pass first order filter. This is how Raul is high-passing his main speakers.
In theory, the benefit is bypassing the sub high-pass filter with the more phase correct first-order cap, releiving the ampo of LF signals, while using the low-pass higher order filter in the sub only. |
As a single-sub user for all of a couple of months, I am considering a second sub. My reasons have to do with smooth and even bass performance, NOT more bass. My single sub is in the front left corner. There is plenty of bass energy, and I have the level turned to almost inaudible. What I have a problem with is the uneven response. Some LF energize the room much more than others.
On a side note, my girlfriend complained about the bass keeping her awake while I was listening late at night. The music level was pretty low, in consideration of her. My home is three levels, listening room on the bottom floor, bedroom on the third floor. When I went upstairs to investigate, the music was barely audible. But when I put my ear to the pillow or bed, the bass was rumbling through. My conclusion is that airborne energy dissipates quickly as a function of distance (inverse exponential function) while the structure is a more efficient conduit for LF energy. I believe my single sub generates plenty of energy, but needs some attention to refinement. Perhaps anti-vibration footers designed for industiral machinery would hep. Anyone try this? Interestingly, I have no problems with vibrations affecting TT playback on my suspended wood floor. But the TT is a Micro Seiki...
My flame suit is on, ready for the jokes about listening to music while my lovely girlfriend is in bed. Gosh, I must be such a geek....
Regards,
scott |
Tonight my next door neighbor very generously agreed to loan me his sub for a couple of days, so that I can experiment with stereo subs. His sub has almost nothing in common with my horn-loaded sub, so the test isn't perfect, but it will do for my purpose. I have it located opposite my sub, in the right corner. I also want to evaluate both subs located even with and even slightly in front of the satellite speakers. This will be a little inconvenient due to the size and weight of the horn sub.
Will share my observations in a day or two. |
Raul- On every single commercial sub set-up I have seen, the subwoofer is set up behind the satellite speakers, usually but not always in the corner. Every single white paper about LF acoustics describes a phase delay at these frequencuies.
So it seems that the subs should be placed at least even, preferably in front of the satellites, nearer the listener, if you want to compensate for phase. Only your system and one other guy I know has it set-up this way. the other guy's system is very nice.
So why does almost everyone put the sub behind the satellites??? Aesthetics? Convenience? Sound?
I am interested in your answer, but I will try placing the subs forward and draw my own conclusion.
Regards,
scott |
After adding a second sub to my system, there was smoother bass response. Again, this isn't about louder or stronger bass, in fact, I was seeking lower, smoother bass. Ironic that the path to this goal was accomplished by adding a sub! My girlfriend is a great listener and concurred that bass was better quality. Since I returned the second sub (on loan from my neighbor), I miss the performance. But, permanently adding a second sub may not be in my short term future. I already stretched to get one large horn sub in my room. A second is really bordering on impractical.... |
I bit the bullet, and repositioned my little horn sub in an experiment to tame uneven and boomy bass in my room. The sub was located in the left corner, behind and to the side of one of the main speakers. I moved the sub midway along the side wall. Now it is similar in position to one of Raul's subs, slightly in front of and to the side of the right main speaker. The initial results are promising! Bass is less boomy, more tuneful, and better integrated with the main speakers. The level is lower (no problem for me) while the LF quality is much higher. I simply adjusted the output level to compensate for the reduced output of two boundaries compared to three in the corner. This is exactly what I wanted. Here are a couple of articles on sub placement I found helpful: http://www.audioholics.com/techtips/setup/loudspeakers/SubwooferplacementP1.phphttp://www.harman.com/wp/pdf/multsubs.pdfRaul, you may not be surprised to know that the second article advocates 4 subs as optimal! |
