Adding a sub in a small roomski.

neekomax · « **on:** 4 Mar 2013, 07:17 pm »

Yo dudes.

Any recommendations for a subwoofer for my small room to smooth out the bass? My speakers have active subs in them; they go pretty low and provide PLENTY of output (gain is at 50% and some might say there's too much bass, but I like it). So it's really just a question of adding a third low frequency source to smooth out the in-room response. That works, right?

Budget is $600ish.

I have one in mind, but I thought I'd solicit your thoughts as well. Thanks so much, audioistas!

Russell Dawkins · « **Reply #1 on:** 4 Mar 2013, 07:38 pm »

There are those who would say go for two cheaper subs rather than one "better" one, especially if smoothness of bass is important rather than ultimate extension. Realistically, for less than ultimate systems, a genuine 30 Hz is plenty, I think. What are your main speakers?

neekomax · « **Reply #2 on:** 4 Mar 2013, 07:42 pm »

Yes, considered that, and it's also what the maker of my speakers recommends.

I have Soundfield Audio Monitor 1s. Here's an interesting review of them done by AC member DS-21:

http://seriousaudioblog.blogspot.com/2012/10/listening-impression-with-cursory.html

*Scotty* · « **Reply #3 on:** 4 Mar 2013, 07:54 pm »

I would shoot for the same 3dB down point for the sub that your mains have and try locating it on the wall behind your listening position. It will optimally work if both the wall behind the main speakers is complete as well as wall behind the listener. How big is the "small room" and what is it's shape?
Scotty

neekomax · « **Reply #4 on:** 4 Mar 2013, 08:47 pm »

Quote from: *Scotty* on 4 Mar 2013, 07:54 pm

I would shoot for the same 3dB down point for the sub that your mains have and try locating it on the wall behind your listening position. It will optimally work if both the wall behind the main speakers is complete as well as wall behind the listener. How big is the "small room" and what is it's shape?
Scotty

The room is roughly 13' (along the axis that goes from speakers to LP) by 12', with 9' ceilings. Currently set up with speakers along the (slightly) shorter wall, with a doorway next to the right speaker. Opposite wall (LP location) is complete.

Here's a video that shows the room from the LP: https://www.youtube.com/watch?v=A1IOqA7lLqQ

*Scotty* · « **Reply #5 on:** 4 Mar 2013, 09:10 pm »

Where are you sitting in relation to the wall behind the listening position, as in how far away?
Scotty

neekomax · « **Reply #6 on:** 4 Mar 2013, 09:23 pm »

Not far at all... less than a foot.

*Scotty* · « **Reply #7 on:** 4 Mar 2013, 09:56 pm »

Chances are good to excellent that you are listening in a major standing wave pressure zone or very close to one, a sub located on this wall and operated out phase should help reduce this. You may also find that moving a little further away from the wall behind you also helps. At least you have the benefit of a regularly shaped room which makes room modes more predictable.
Scotty

neekomax · « **Reply #8 on:** 4 Mar 2013, 10:01 pm »

Ok thanks. How does the out-of-phase thing work? Can you explain the physics behind your suggestion?

Also, any sub recommendations?

*Scotty* · « **Reply #9 on:** 4 Mar 2013, 10:50 pm »

Sounds that are equal and opposite in phase will cancel one another out. This is the principle behind noise canceling headphones. In theory if we operated two subwoofers out phase on opposite walls in the same room we could achieve a zone where the two wavefronts exactly canceled one another out and we would have no bass at all in this region.
This never happens in listening room under real world conditions. What we are hoping for is to be able to partially cancel out the excess pressure at the listening position by using a sub out phase with mains and evening out the pressure in the room. You should be able operate the sub at much lower SPL than the mains and achieve an improvement in the bass quality. A cheap sub with a wooly sound will tend to muddy up the bass of the total system.
Scotty

Russell Dawkins · « **Reply #10 on:** 4 Mar 2013, 11:21 pm »

Scotty, wouldn't this phase cancellation be frequency-dependent? In other words, wouldn't you get cancellation at one frequency only and reinforcement at another frequency, depending on wavelength?

*Scotty* · « **Reply #11 on:** 4 Mar 2013, 11:48 pm »

Both the signal to the sub and the mains below the Schoeder frequency are the same, differing only in absolute phase. Obviously in the real world this is an inexact application. Operating the sub in the rear out phase should help a great deal more than operating it in phase with the front. Symmetrical placement of two subs in the rear of the room with respect to the position of the front mains would make an optimal outcome more likely. Here are my before and after measurements with the rear sub in and out of phase. When it is in phase it it contributes to the problem.

Unfortunately the room modes in my room are chaotic and even moving the mic location a few inches in any direction changes the frequency response. The system behaves as though EQ had been applied to produce flat response at a single mic position. In a room with a regular shape, either square or rectangular, the room modes would be much more predictable and there should be less variance in frequency response with minor changes in the mic's location.
Scotty
My bad, the first graph is without the aux subs on. I failed to save the graph showing the effects of operating the subs in phase with the front mains. The graph was actually quite similar, there was a broad increase of about 10dB above average from 30Hz to 80Hz.

neekomax · « **Reply #12 on:** 5 Mar 2013, 12:29 am »

Thanks for explaining a bit further, that helps.

No one has a sub recommendation?

Doublej · « **Reply #13 on:** 5 Mar 2013, 02:48 am »

A Hsu will do it for you.

medium jim · « **Reply #14 on:** 5 Mar 2013, 02:50 am »

I like B&W's...

Jim

JohnR · « **Reply #15 on:** 5 Mar 2013, 07:26 am »

Quote from: neekomax on 5 Mar 2013, 12:29 am

No one has a sub recommendation?

It would probably be helpful to actually say what sub it is that you already have in mind.

And at this point, look into whether it meets some of the suggestions that have been made in the thread already.

DTB300 · « **Reply #16 on:** 5 Mar 2013, 02:11 pm »

There are quite a few subs in the $600 range - 8", 10", & 12" (I happen to be looking around at just this range and trying to get out this weekend to hear some of them - looking for a pair for my room)

ML Dynamo 700 (10” 300w Class A/B) ($600)
B&W ASW610 or ASW610XP (10”, 500w Class D) (610 = $650, 610XP = $1200)
REL T5 (8” 150w A/B) ($700)
REL T7 (8” active +10” Radiator 200w A/B) ($1000)
Canton 10.2 (10” 200w D) ($899)
SVS SB-1000 (12" 300w D) $499
SVS NSD-12 (12" 400w D) $649
Rhythmik F12 (12" 375W D) $850

I am sure there are others I have missed....

rooze · « **Reply #17 on:** 5 Mar 2013, 02:47 pm »

Vandersteen 2WQ - a pair preferably.

neekomax · « **Reply #18 on:** 5 Mar 2013, 03:09 pm »

Hey, thanks for the reccos.

I'm considering the SVS SB-1000, because it seems well powered, and it's a sealed design, which might blend with the sealed sub enclosures in my mains. Also seems like good value compared to others I've looked at. http://www.svsound.com/subwoofers/sealed-box/sb-1000#.UTYJd3xARfs

Anybody know what "...this amp features a highly advanced DSP processor offering unmatched control over the subwoofer at all drive levels, for the ultimate in refined behavior." means?

Also, it has variable phase control, which I guess might be useful for tuning the sub to reduce standing waves? Is that right?

The Vandersteen sub seems to sell for $1,200 or so, which is double my budget.

I will look into some of those you listed, DTB300.

DTB300 · « **Reply #19 on:** 5 Mar 2013, 06:50 pm »

All of the subs I listed are sealed and not ported...