[saisunil]

I like monitors for what they do - great imaging, easier to set up, room friendly, simpler crossover etc. compared to the three way speakers.
I am going to add subwoofer in the 2 channel system.

I would like to know your experiences (ideally in your listening room but other comments are also welcome) regarding integrating the subwoofer in a medium sized room with two way stand mount speakers.

My room is 12 x 21 with half opening to foyer on one end. Speakers are custom made with 91 db sensitivity - very neutral. Useful low end response in 40's Hz.
I have Mondo Corner Traps in four corner walls and one each at the first reflection points.

I have read a few theories regarding subwoofer:
1. Multiple subs (2 or more) are better than one - for a smoother in room response
2. Sub with DSP is preferred to a Sub without DSP - DSP takes care of smoothing out in room response.
          Do you still need more than one Sub with DSP?
3. Single sub is the most pragmatic solution - when I have to share my system with a living room

I miss the bass mostly at low listening level or with CDs with less recorded bass. At 85 db and up SPL - I get satisfactory bass in my current system without sub.

At Danny's suggestion (GR-Research) I am planning to get
http://www.rythmikaudio.com/gr-amplifiers.html

I am looking for the presence factor and the low end response that one gets in floorstanding. I am looking for anything below 30 Hz in my medium sized room.

Thanks for your responses.

Regards
Sunil.

[Haoleb]

A couple months ago I built a pair of DIY subs utilizing the Infinity Kappa perfect 12vq driver in a large slot port enclosure tuned to 20hz, It was not a cheap endeavour, but the results are well worth it. I have never been as pleased with my system as I have been after adding in the subs. And I used to think I had plenty of bass out of my towers..

I use the Behringer DCX2496 for crossing over the subs and my other speakers as well as to eq the response. Powering each of them is a qsc rmx1450 bridged.  In my opinion something like the DCX is absolutely critical, I can easily switch between the EQ being on and Off and the difference is immediatly noticable, All the bass notes sound like they are the same volume level vs some kinda quiet and some much much louder.

I definetly think stereo subs with dsp is the way to go. I did not like the Idea of eqing the response at first but the enjoyment I have gained is so worth it

[saisunil]

Thanks for your response ...

I too believe that stereo sub with DSP would give the most even low end response - yet I am hoping I can get away with one sub with no DSP 

I am looking to discover a middle ground of some sort - give that I have decent room treatment from real traps.

Please keep your responses coming.

Thanks
Sunil.

[konut]

In my limited experience with subs, I find placement to be the key factor determining smoothness of response. To be clear, its not that the sub should be placed equidistant between the speakers, but where it will excite the least amount of room modes. This depends highly on the dimensions of the room. Some rooms will not be tamed. I have a sub now with eq, and I've found that recordings vary so much in response that when the sub is eqed flat some recordings sound great while others are lumpy. Lately I've bypassed the eq and let the chips fall where they may. As far as integration is concerned, I'm in the camp that believes steep 24db per octave low and high pass filters ensure the least amount of overlap, resulting in a smooth transition. As far as low level listening is concerned, the extension of response with a sub,while pleasing, is not going to compensate significantly for the ears' non-linearity. Fletcher-Munson and all of that.

[Bob in St. Louis]

My system (all open baffle) has never sounded better than when I implemented the Behringer DCX2496 below 80Hz to help control two (slightly unorthodox) separate subs.

Here's the current configuration:

- Main 15" coaxial channels 24db slope starting at 80. (NO DSP at all)
- (Two) 15" mono subs (bass augmenters actually) 80Hz down to 42Hz with 24db slope.
- (Four) Infinite Baffle 15" drivers from 42Hz down to their natural roll off (have not measured yet where that is).

The two 15" bass augmenters are sitting next to the main channel (coaxial) drivers, so essentially you could call these three way speakers, they just happen to be separate units.

It is my belief that alleviating each driver from the lower end of it's "comfort range" will help it perform better overall.
This way, everybody does what they're designed to do without the least bit of strain. At least it works for me.

Hope this helps Sunil,

Bob

[sbrtoy]

Personally I don't much care to add to the signal path by using DSP particularly with less than stellar circuitry like the stock Behringer, however I won't bash it at all as it can be very useful. 

If your main speakers are ported as mine are they will roll off abruptly anyhow, and setting the sub crossover frequency and EQ on my sub gets me excellent extension and more grunt in the 60-80hz range.  I use the Dayton external sub amp with excellent results as I use the EQ to cut the range from around 35-75hz, and then roll off above that with the crossover.  This allows authority down to the low 20's for organ and synth bass, while still allowing enough support higher up to get convincing scale on bass drums etc.

As always YMMV!

[saisunil]

I guess it won't hurt starting with one sub without dsp and then take it from there ..
Thanks all for responses, please keep them coming.

Regards
Sunil.

[Bob in St. Louis]

Better to start off small and add more components as you feel the need.
You can always stop adding when you're satisfied with the results. 

Bob

[Norman Tracy]

Sunil,

I voted 2-subs with DSP because my current rig using DEQX DSP driving dual push-pull TC sound 10" subs is the best I have achieved thus far. Calibrated DSP + long excursion drivers in sealed enclosures + 2kW of ICEpower gets the job done.

If this were Chicago and I could vote twice I would also add 1-sub without DSP because a single REL sub using their leave the main speakers full range and fill in with the sub scheme was the first which for me yielded audiophile quality musical results. Many have a problem with this because the REL low pass filter is often set to 20-30 Hz (!) and they feel they are not getting their moneys worth unless the sub is set to work up to 80-100 Hz. What is forgotten is these crossovers in the analog domain are only 6 to at best 24 dB/octave which leaves a lot of output well above the set point. I have also heard notch filter equipted systems, specifically Revels, transform from home theater boomers to subtle and musical after the notches are set to the room mode frequencies using instrumention.

In summary:

Cost, complexity, and size budgets wide open then go with multiple subs and DSP. These systems can be deep, loud and musically subtle.

For a compact reasonable solution look into REL. Not as much output and you loose the true bi-amping benefits but they are simple and like a good doctor first do no harm.

[Duke]

Note that DSP can correct the in-room response for a single microphone location; that same correction may well produce an even worse in-room response in other locations, because room modes that produce a peak at a given frequency in one location will produce a dip elsewhere.  So DSP with a single sub is most beneficial for one listening location, and may well be detrimental in other locations.

Now once you move up to two subs with DSP, those two subs will each energize the room's bass modes differently (assuming they're spaced far apart and preferably asymmetrically), so there will be less variation from one location to another before you start to apply DSP.  In this case, DSP will not result in as much of a discrepancy between bass smoothness in the listening position and elsewhere in the room.

As you go beyond two asymmetrically distributed subs, equalization is more likely to be beneficial throughout the room because the soundfield is becoming more uniform throughout the room.  But as you increase the number of distributed subs, you will probably have less need for equalization to begin with.

Duke

[doug s.]

i would recommend two subs, actively crossed over to your mains.  whether or not you use a normal active x-over or a dsp x-over depends on your room & set-up.  i have found that dsp is useful for mains as well as subs.  but, stereo subs w/active x-over also works really well, imo...

doug s.