[Mike Dzurko]

Are two small subs better one large ?

it depends how large and how hungry you are .     

Some think our Maestro XL is a big sub, but THAT is a BIG sub!

[rabpaul]

Hi,

Don't you think the size of the room is also an important consideration?
What would be the minimum size for room to accomodate 2 subs?
Don't you think how low your main speakers go down to is another?
How much stereo bass content is there below say 35Hz?

Rgds
Rabin

[jules]

TWO!!

you're kidding. Maybe refrigeration would be more important

Jules

[Duke]

A major problem with trying to reproduce bass in small rooms is this:  The reflected bass energy bouncing off the room surfaces re-combines with the direct output to produce significant peaks and dips at the listening position.   

For instance, let's assume you have a single subwoofer positioned along the front wall, between your speakers.  There is one path length from the subwoofer to the listening position, and there is another path length from the subwoofer to the wall behind you, then reflecting back to the listening position.  At the frequency where the difference in these two path lengths is equal to one-half wavelength, the bass energy reflecting off the back wall will arrive out-of-phase with the direct sound and a cancellation notch will occur.  At the frequency where the path length difference is equal to one wavelength, the bass energy reflecting off the back wall will arrive in-phase with the direct sound and a reinforcement peak will occur.  Similar path-length-related peaks and dips will occur based on reflections off of the other room surfaces.

The peaks and dips can be addressed with equalization, but I think there's a better solution.  The problem is fundamentally an acoustic one, so let's analyze it that way and look for an acoustic solution.

Note the problem is not that there are too many of these path-length-induced peaks and dips in the bass region - the problem is that there are TOO FEW of them!  They end up being spaced far enough apart to be quite audible.  At higher frequencies we also have path-length-related peaks and dips, but they are spaced so close together that they combine into a much smoother reverberant soundfield. 

If we were trying to be technical, we might say that in a small room the bass energy is well "correlated".  What we want is "de-correlated" bass energy - that is, we don't want distinct peaks and dips resulting from reinforcement and cancellation.   Fortunately, there's a way to de-correlate the bass energy in small rooms:  Use multiple low frequency sources scattered around the room.

Going back to our original example, suppose we scoot the first subwoofer over towards the right front corner.  And suppose we add a second subwoofer along the left side wall, slightly behind our listening position (but still not too close to the left rear corner).  And we feed both subwoofers the same signal.  Now the path-length-difference induced peaks and dips from these two scattered low frequency sources will never coincide anywhere in the room!  So we have taken a major step towards smoothing out the bass everywhere in the room by de-correlating the low frequency soundfield.  In my opinion this acoustic solution is superior to equalization using a single subwoofer because it's effective throughout the room, not just in one area.

So if the choice is between one big and two small subs, my vote is for two small subs scattered, and driven by the same (mono) signal.

Duke

[rabpaul]

Duke,

I see your point but what is being advocated is so called stereo subs. They in theory won't get the same signal being connected to each of the two speakers and in will be placed in the exact position as the other i.e they won't be scattered subs.

Rgds
Rabin

[duggie]

i agree w/everything duke says, except i would stick w/stereo subs - there *is* ambient stereo information in low frequency recordings.  all you have to do is compare the sound - which you can do with an outboard x-over like the marchand xm9LL - it has mono sum capability for the bass output.  if you have a small room, use something like the marchand, & you can experiment, & decide which works best for yourself.

[Night_Train]

Are two small subs better one large ?

it depends how large and how hungry you are .     

Actually, that set-up looks to me like miniature(s) and what the film industry calls "forced perspective." 

[jhw59]

newbie to this forum but this is an interesting question. I'm pulling together an HT rig and thought about two subs but I am on a budget. What impact does room size (mine is 12/15/9) make on whether to go with two or one sub?

[duggie]

newbie to this forum but this is an interesting question. I'm pulling together an HT rig and thought about two subs but I am on a budget. What impact does room size (mine is 12/15/9) make on whether to go with two or one sub?

imo, two subs is always better for 2-channel audio.  smaller room makes bass integration difficult, (with or w/o subwoofers), & 2 subs is easier to integrate than one, imo, so all the more reason to go with two. 

i am not into ht at all, so i am not sure how the issues would change, except for ease of room integration, which should be the same, regardless of whether you're doing audio or ht.

[gooberdude]

I have little experience with a sub in the home, but back in the day i had dual voicecoil JL Audio subs.

It seems like most of the home subs avail only have single voicecoils....Is there a home sub that plays both channels from the same enclosure, or even same driver (dual VC)?.   if not, whats the reason?

matt

[duggie]

I have little experience with a sub in the home, but back in the day i had dual voicecoil JL Audio subs.

It seems like most of the home subs avail only have single voicecoils....Is there a home sub that plays both channels from the same enclosure, or even same driver (dual VC)?.   if not, whats the reason?

matt

vmps used to offer a dual-voicecoil option; i am not sure if they still do.  their large subwoofer, w/two drivers, could be used to play two channels from one enclosure.  but, i would still go w/two separate subs, whenever possible...

[Mike Dzurko]

I have little experience with a sub in the home, but back in the day i had dual voicecoil JL Audio subs.

It seems like most of the home subs avail only have single voicecoils....Is there a home sub that plays both channels from the same enclosure, or even same driver (dual VC)?.   if not, whats the reason?

matt

We used to offer a dual voice coiled passive sub many years ago. These days, most subs are active and the summing is done in the electronics.