Please see the room diagram in the attached PDF. Since making that PDF I have rearranged the TV and the couch so the TV is parallel to the glass door with its back about a foot away from it, and the speakers are on either side of the TV about a foot away on each side and about a foot in front of the TV screen. The couch is now in the center of the room, facing the TV.

The "tri-traps" are not there yet; those are just two of the locations I was planning to put them.

The floor is porcelain tiles and the wall is just regular drywall (acoustic panels will be added to them, but I'm starting with the bass first). I'm also going to eventually get rid of the plastic blinds and get curtains instead.

Do you think 4 traps will be sufficient -- one in each corner? Or should I plan for at least 8 of them (2 stacked in each corner)? Or do you think more will be required for it to matter?

4 will give you an improvement, 8 will make it even better.

Please see the room diagram in the attached PDF. Since making that PDF I have rearranged the TV and the couch so the TV is parallel to the glass door with its back about a foot away from it, and the speakers are on either side of the TV about a foot away on each side and about a foot in front of the TV screen. The couch is now in the center of the room, facing the TV.

The "tri-traps" are not there yet; those are just two of the locations I was planning to put them.

The floor is porcelain tiles and the wall is just regular drywall (acoustic panels will be added to them, but I'm starting with the bass first). I'm also going to eventually get rid of the plastic blinds and get curtains instead.

Do you think 4 traps will be sufficient -- one in each corner? Or should I plan for at least 8 of them (2 stacked in each corner)? Or do you think more will be required for it to matter?
I'm glad you switched orientation, since working with an unbalanced (wall on on right side, open space on left) room would have been a waste of time trying to deal with the acoustics.

The corners that are most important are the ones in front (not in general, but in your specific room). Put two tri-traps in each. Totally cover the corners.

Now, the "back" corners would be in the dining room? Not sure if you want to put more tri-traps in there... I'd look at other wall-ceiling boundaries for bass trapping. Any area that forms a 90 degree angle is a candidate for bass trapping.

In a room of that size, you really want to try to reduce LF modes. In doing that, you will end up with a somewhat reflection-free space. This is good for home theater, and can be good for music, but can feel a little claustrophobic for socializing.

You can never have enough bass traps it seems. You might be able to use the bedroom doors to your advantage - can you leave them open? An open door can be an effective bass trap. With your new orientation (which is a good thing) you might find that the big glass doors also act somewhat as bass traps (bass goes through thin windows pretty easily, not so well with double glazing).

Actually, you can have too many bass traps. If they cover up wall space which is better used for control of other frequencies, then that's too many.

But it is also true that you probably cannot have too many to treat very low (lowest subwoofer) frequencies. Even stacking many bass traps floor to ceiling can have minimal, if any, effect in the neighborhood of 50 Hz and below.

- Terry

4 will give you an improvement, 8 will make it even better.

And 20 will be better still. :D

--Ethan

And bass traps don't have to triangular. Put a table against the wall. Fill the volume under the table top with high density fiberglass (or rockwool), cover it with fabric, and you've just made a bass trap. Or get a couple rolls of fiberglass insulation (leave them in the plastic to keep them compressed, and to reduce excessive high frequency absorption). Stack them up in a corner, drape pretty fabric over them, get a nice top for it and put something pretty on top - cheap easy quick basstrap that is not too ugly. I'm sure you can have too much bass trapping, but it is probably easier to have too much high frequency absorbtion IMO

How many bass traps to make a worthwhile difference? All of them. :)


Tim

If they cover up wall space which is better used for control of other frequencies, then that's too many.

You can get panels that are trapping at lower frequencies, but diffusing at higher, to take care of that :-)

But it is also true that you probably cannot have too many to treat very low (lowest subwoofer) frequencies. Even stacking many bass traps floor to ceiling can have minimal, if any, effect in the neighborhood of 50 Hz and below.Wouldn't the sub-50Hz frequencies just go through the drywall anyway?

You can never have enough bass traps it seems. You might be able to use the bedroom doors to your advantage - can you leave them open?I can, but I think the bass sounds and feels better when they are closed. Probably something to do with the ability of the sub to "pressurize" a closed area more effectively.

Wouldn't the sub-50Hz frequencies just go through the drywall anyway?
If all of it did, we wouldn't have any reflected by the drywall of the room to create nasty low frequency room modes. But we often have them this low (governed by your room dimensions), which means enough of this very low frequency sound is being reflected back and forth to cause a resonance! In practice, we generally get the worst of both worlds -- bass resonating within the room, and bass transmitted to nearby spaces.:(

I have designed bass traps to handle such very low frequencies. However, they are enormous, and not practical for most people.

- Terry