Question About Small Subwoofer Accuracy

[fredk]

Thats an interesting read Matt and it represents one point of view, but I don't personally agree with a number of things he writes. Unfortunately, I also don't have a whole lot of subs to experiment with to test out various points of view.

The one thing that all the heavyweights in the industry agree on is that you need multiple subs for the best overall response.

If you have the time, go to diyaudio.com and do a search on Earl Geddes. There is a very interesting thread on multiple subwoofers. Some of the posts get very technical and are beyond my understanding, but its a good read none the less.

The biggest thing I took away from it was that everything from localization to optimal room placement is very much room Dependant.

In my room, at an 80hz crossover, there is no localization of bass. It doesn't seem to matter where I place the sub.

On most of the rock material I listen to I also cannot tell the difference between mains only and mains + sub. Multiple subs may make a difference since they would could potentially smooth out the region around the crossover.

 

[Matt34]

Thats an interesting read Matt and it represents one point of view, but I don't personally agree with a number of things he writes. Unfortunately, I also don't have a whole lot of subs to experiment with to test out various points of view.

The one thing that all the heavyweights in the industry agree on is that you need multiple subs for the best overall response.

If you have the time, go to diyaudio.com and do a search on Earl Geddes. There is a very interesting thread on multiple subwoofers. Some of the posts get very technical and are beyond my understanding, but its a good read none the less.

The biggest thing I took away from it was that everything from localization to optimal room placement is very much room Dependant.

In my room, at an 80hz crossover, there is no localization of bass. It doesn't seem to matter where I place the sub.

On most of the rock material I listen to I also cannot tell the difference between mains only and mains + sub. Multiple subs may make a difference since they would could potentially smooth out the region around the crossover.

I've read some of Dr. Geddes thoughts on this and am implementing some of his work into my setup. I've become a huge advocate that placement is key above anything else. I'd rather have two-four lesser (smaller) subs than one big expensive one. Right now using a PA-120 and a TSC ASW-8 I'm getting some of the best bass I've experienced in my room. Being able to move these smaller subs to areas I couldn't move the Kappa's too have flatten out the FR and gave me the tactile feel that no other setup has given me. I'm seriously considering sending the PB-10 back and picking up two more PA-120 because of their smaller size. I'll gladly give up a couple db down low to get the response I'm getting now with the freedom to move the subs to the most ideal positions.

 

[WmAx]

I used to try to recommend people get 4 to 6 $300-$400 subs rather than any expensive unit, as this will always have superior bass, plus the multiple smaller subs add up to BIG spl capability. References to Toole's work on this subject never made a difference either. In any case, I have always recommended a minimum of two subwoofers.

As far as know... not a single person would ever actually get the 4-6 lower cost subs.... LOL.

For a dream set up.. imagine 6 JL Audio 8" W7 based sub cabinets, each about 10-12" cubed, placed throughout the room.

This 6 x 8W7 set up could easily, in an average room, achieve 110-112db at 20Hz, 120db at 30Hz, 125dB at 40Hz. You would need 500 watts per channel and something like a DCX2496 to correct the response curve for flat response to 20 Hz.

-Chris

 

[Matt34]

I used to try to recommend people get 4 to 6 $300-$400 subs rather than any expensive unit, as this will always have superior bass, plus the multiple smaller subs add up to BIG spl capability. References to Toole's work on this subject never made a difference either. In any case, I have always recommended a minimum of two subwoofers.

As far as know... not a single person would ever actually get the 4-6 lower cost subs.... LOL.

-Chris

Dr. Geddes advocates using three different subs each used for a specific band in the lower frequencies. This I don't totally buy into (maybe if I had a DCX 2946 to do it properly) but I am going to try using three of the same subs all playing 23hz-80hz.

 

[WmAx]

Dr. Geddes advocates using three different subs each used for a specific band in the lower frequencies. This I don't totally buy into (maybe if I had a DCX 2946 to do it properly) but I am going to try using three of the same subs all playing 23hz-80hz.

There is no reason to use different subs to cover different sub bands if the sub is designed properly in the first place. Credible articles show that the subs should be identical, and when placed/distributed properly, result in maximally flat/linear room response.

-Chris

 

[fredk]

There is no reason to use different subs to cover different sub bands if the sub is designed properly in the first place. Credible articles show that the subs should be identical, and when placed/distributed properly, result in maximally flat/linear room response.

I understand what you are saying Chris, but Dr. Geddes has a great deal of credibility as well and what he proposes is based on science and measurements.

The few people I have found that have implemented parts of what is proposed seem to be getting good results. I wish I had the money to play.

 

[fredk]

I'd rather have two-four lesser (smaller) subs than one big expensive one. Right now using a PA-120 and a TSC ASW-8 I'm getting some of the best bass I've experienced in my room. Being able to move these smaller subs to areas I couldn't move the Kappa's too have flatten out the FR and gave me the tactile feel that no other setup has given me.

I got all wound up on the super big super low subs when I first started reading, but as I explored the practicalities in my small living space, it became obvious that it just didn't make sense to me.

I'm actually toying with the idea of 3 or 4 CSS SDX7s for the upper bass and something like an SDX15 for the low stuff.

I like the idea of the small driver for the upper bass because they can be put in such small boxes. My main space is only 1700 cf. so I don't need a ton of output. It facilitates placement and blending in to the rest of the room.

Now if only I could find some cash so I can play...