2-Channel Subwoofer Integration


Well-Known Member
Sep 26, 2013
A well-positioned subwoofer significantly improves the foundation and spatial reproduction of the music. Sometimes it helps to raise the subwoofer 40-60cm from the floor in order to achieve more even room stimulation. Peaks and valleys in the frequency response are smoothed.


Well-Known Member
May 7, 2015
Floyd Tool, Tod Welti, Earl Geddes among others have talked about the benefits of using multiple subwoofers for years and many are using this principle with great succes and if one looks at it from a scientific / acoustic point of view, it makes perfect sense. If you add the program Multi-Sub Optimizer Software into the mix


and implement it properly, you have a very powerful tool, that will give you a very consistive seat-to-seat bas response. It will also integrate the subs with the main speaker for a seamless transition. Further more the program, through eq, delay and gain will improve the spatial distribution of acoustic pressure and particle velocity in the bass.
You feed the program with the appropriate measurements (see instructions) and the program will then calculate the settings for each sub (and mains optionally).
I was stunned at how accurate the program predicted my bass response at 5 seating locations, after I verified it with REW. And the bass it self, is just spectacular. No bloating or ringing, just tight natural even bass. There is a small learning curve, but once you get the hang of it, it is actually fun to use, because you can watch your future in room bass response change for the better, while the program crush the numbers.

No more guessing and using countless hours of trail and error, of dialing in the bass response and still only achieve sub-optimal results. Do the ground work of measuring each sub in different seatings and then let the program do the rest. You can even export the final sub settings as biquads to the DSP, so it can't be more easy than that. Enjoy!

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Well-Known Member
Mar 28, 2017
Yes. MSO works quite well. What it predicts is very close to what will be measured once you input the recommended DSP filters. If you are new to measuring then there is a good bit of learning curve -- learning to setup and use REW, learning how to use MSO and also learning how to make the inputs to the DSP. MSO is also "picky". By this I mean you have to follow EXACTLY the right process. Any deviation will result in far from optimum results.


Well-Known Member
May 31, 2012
I have used subs, both RCA input and then to compare running out of my amp like my main speakers, but subs had their own built-in amps. I easily heard the improvement when running directly from my amp, REL also suggests that way. Now with a Speaker that can produce the best bottom end I've heard from stand-alone speakers, I no longer need to use a sub and in fact, they now take away from the reproduction of my system. Those speakers are open-baffle Spatial Audio Sapphire 3's. In-room I am hitting 28Hz or so, but so clean and fast with texture and detail. The speakers sound purer without them, with my other speakers like my Quads, they made a positive impact, now they make their impact where they should be in the HT system, where they make movie watching enjoyable. The learning point from this was some speakers don't need subs and in fact, you may hurt the sound depending on the speakers and the quality of bottom-end they can put out. In audio, there are no absolutes.


Well-Known Member
May 7, 2015
Agreed, a bit of a learning curve if you start from scratch. But if you can handle a mic + REW (or another audio software) you are almost half way there :) When I see what people has invested in their systems, both financially and time wise, I really believe learning MSO is a very small investment in time (it is freeware program) and the end result will lift any system by magnitude of order. Floyd Toole stated that the bass stands for 30 % of what people consider good sound and we are only talking of the first 100-200 hz.

Lets say you have main speakers going down to 40 hz. Then 1 sub, placed in a corner, going down to say 20 hz would, in most normal settings be sufficient, for getting a nice flat bass response. You can of course make a bass tilt, to serve your preferences. Adding more distributed subs will improve seat to seat variation and make each sub work less hard, thus lowering distortion and greatly improving total max output, as MSO will make the subs work together more smoothly. You don't even have to use similar subs, as MSO will take any frequency/phase issues into account.

If one implement science and psychoacoustics into their audio system, it will start to sound like art :)

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