Dual sub-woofers??

[piece-it pete]

I have tried(and still do use) stereo subs. While I try not to dispute what people say they hear, I know for a fact that the cues that represent soundstaging are not found in the bass frequencies. Phase information is not easily discerned in the bass region, and few sources have directional bass. Movies come to mind as the only sources that contain bass in multiple channels. Classical music may contain stereo bass, but it takes a specific microphone placement to make it audible, and the acoustics of the recording venue may prevent it from sounding discrete enough to be interpreted as stereo. If you hear any stereo information, it is likely because of audible harmonics associated with the fundemental bass tone. You may be able to feel the direction of the bass wave, but I seriously doubt you can hear it.

I will admit the possibility that my mind is tricking itself. If it is, it's doing a great job! So for now, I'll reserve judgement. What advantage do you attibute to stereo subs? Followup: How do you look at it differently due to Richards' input? I have to admit, he gave me a lot of advice early on, but I have to learn the hard way - stubbon like a ........?mule? lol

Are you getting you bass from a sub channel, or from the mains directly?

Current setup:
Preamp -> active crossovers (24db slope, all outs in phase) -> +80hz to amp, mains; -80hz to amp, subs.

I would say any directionality that you experience would have to come from the mains. You may perceive some directional bass in very large rooms, but the size of most listening spaces prevents any phase variances between channels from beng heard in the deep bass region.

Again, I will reserve judgement but continue to observe? with your input in mind.


Oh straighten up your bloomin posture my good man. Chin up, gut in and all that rubbish

Yessir! But I don't know if I can get my gut in anymore......

Pete

[the hand of boredom]

Doc,

(Or Terrible) If you were on a budget, would you get a few bass traps or EQ for the best bass response you could afford?

THOB

[Sir Terrence the Terrible]

Doc,

(Or Terrible) If you were on a budget, would you get a few bass traps or EQ for the best bass response you could afford?

THOB

Dang bored hand, this is a tough one!! Doc may have a different answer than I have, but I always go acoustic before electric. So I would get the traps(because I know they help), and If I had anymore problems I would get the eq later. A good eq is not that expensive( I paid $125 buck for each of mine) and if the traps don't take care of all the acoustical problems, then an addition of a eq, along with the traps, probably can.

[the hand of boredom]

Dang bored hand, this is a tough one!! Doc may have a different answer than I have, but I always go acoustic before electric. So I would get the traps(because I know they help), and If I had anymore problems I would get the eq later. A good eq is not that expensive( I paid $125 buck for each of mine) and if the traps don't take care of all the acoustical problems, then an addition of a eq, along with the traps, probably can.

OK, Sir T. You say traps. If I were to get traps, then I should start in the front corners of the room?

Another question, or two, if you don't mind answering. Some say size doesn't matter. Does altering the diameter of the trap affect the absorption rate of various frequency? If I have a boom at 85hz is there a particular size of bass trapping that will work best? Or is it like everything else in audio where you buy, listen, evaluate, get pissed off, buy some more?

Thanks again, Your Terribleness.

THOB

[Richard Greene]

A dedicated parametric EQ for a subwoofer costs as little as $120 + perhaps $60 more for a Rat Shack sound meter and a test CD with 1/6 octave (or closer) spaced sine waves. I don't recommend using a cheap digital parametric EQ such as my Behringer Feedback Destroyer for full-range speakers because it will cause a small deterioration of sound quality in the mid-range and treble. Not something I'm looking for.

A parametric EQ will allow you to flatten all bass peaks at one listening position simply by launching less bass from the speakers to compensate for in-phase reflections that make the bass too loud at that seat. Since you are using EQ to reduce the SPL at some standing wave frequencies, the room ringing at those frequencies will fade to inaudibility faster than before EQ.

Whether EQ corrections improve or deteriorate the bass frequency response at other seating positions depends on which opposing surfaces cause the standing wave.
In general, EQ set for one listening position is more likely than not to improve the bass at another listening position.

EQ is obviously most effective for two-channel audio where only one listener can sit in the sweet spot at one time. With home theater, the more listening seats you have,
the more likely EQ set for one seating position will make the sound worse at one or more other seating positions.

Bass traps work on bass peaks too ... and also on bass nulls ... and on room ringing (slow decay) at ALL standing wave frequencies.

However you will usually need to fill 2% to 3% of a room's total volume with tubular bass traps to flatten the bass frequency response enough so that EQ is not needed.
That may require 12 to 16 tubular bass traps. Two corner bass traps will have a barely measureable effect on bass frequency response (although you may notice the room ringing is somewhat damped). Four corner bass traps should cause a small effect on the bass frequency response.

The best solution is to use as many corner bass traps as feasible (usually not many if the room is shared with a female) plus a dedicated subwoofer EQ.

[the hand of boredom]

Am I correct in guessing that the best configuration for 'dual subwoofers' in two-channel would be as follows?

Have the sub on the left side of the room handling the left signal in conjunction with the left main, with the main high-passed somewhere and the subbie handling the rest. The sub on the right side of the room doing the same, only handling the right signal?

This would mean each 'side' is operating as a full range system?

PAYCE!

THOB

[Richard Greene]

Dual subs integrate best (sonically invisible) when they are used in a left-right configuration.

If you sharply restrict output over 80Hz. dual subs can also be placed on the same side of the room where they will still be sonically invisible almost 100% 0f the time.

Whether dual subs are connected as stereo or mono subs barely matters as few studio recordings (two-channel) have stereo bass content. Some classical recordings made in large venues may have audible stereo hall ambience.

If you sit half way between the side walls of a room, the bass frequency response from a pair of subwoofers on the same side of the room will usually be better than using
left-right subwoofers.

I personally use one mono subwoofer just to the outside of my left speaker for two-channel audio. My crossover and parametric EQ allow me to sharply restrict output over 80Hz. so no male voices can be heard through my subwoofer when the other speakers are turned off.

[Geoffcin]

Am I correct in guessing that the best configuration for 'dual subwoofers' in two-channel would be as follows?

Have the sub on the left side of the room handling the left signal in conjunction with the left main, with the main high-passed somewhere and the subbie handling the rest. The sub on the right side of the room doing the same, only handling the right signal?

This would mean each 'side' is operating as a full range system?

PAYCE!

THOB

That's exactly as I have them. Also I keep them as far away from any wall as possible. The closer you get to a corner the more apparent output you have, but the more room nodes you excite.

[the hand of boredom]

That's exactly as I have them. Also I keep them as far away from any wall as possible. The closer you get to a corner the more apparent output you have, but the more room nodes you excite.

When your system is in HT mode, are you running with the sub out on the receiver/processor set to NO and sending all the LFE to the subs via the mains (if I understand all your configs) ?

Also, I thought having the subs closer to the wall excites LESS nodes.

THOB

[Geoffcin]

When your system is in HT mode, are you running with the sub out on the receiver/processor set to NO and sending all the LFE to the subs via the mains (if I understand all your configs) ?

Also, I thought having the subs closer to the wall excites LESS nodes.

THOB

Actually my subs are not included in the HT setup. They are run from my preamps output, and only get what I feed the maggies. I use two Velodyne FSR-15's with my 3.6's, and for the most part they do nothing but take up real estate. In no way have I ever had them breathing hard, even when playing my maggies at concert levels. On the other hand, I've found maggies to be very volume sensitive when it comes to the bass response. By having the subs it give me the ability to augment the bass for low level playing. I set the crossover higher when playing at low volume, and boost the sub level a little. While this gives a nonlinear response curve, it's much more pleasing to listen to.

As soon as you raise the volume up to say ~85 dB or so, the maggies open up in a big way, and the extra bass from a sub is not needed, at least in my room. I usually will turn the crossover down to 40hz and leave it there.

In my HT setup I use only the CSW T500 mains as subwoofers. They have 300 watt amps built into each speaker, and although there's less maximum output, and more distortion than the Velodynes, there's still ample output to shake just about everthing in the house. I've tried using the Velodynes in the HT setup, but it just wasn't nessassary.

As you can see in both setups I'm using dual subwoofers, so I do reccomend it.