I saw someone post a HT layout that had the sub under the center channel. I've read a little about placing a subwoofer under the center channel, but I have a few more questions.

1) The previous threads said there was no issue placing the sub under the center channel. I'm not sure about what to do with acoustically absorbing material in this case. The sub would be under the center channel, behind the screen & false wall. Would you still deaden the wall behind the false wall in this case? Or is the sub frequency low enough that it isn't affected by standard deadening material like duct liner?

2) What about bass traps? If you have bass traps in the upper front left and right corners would they affect the performance of a sub placed between them (though on the floor)?

3) The bottom frame of the screen would be a little lower and/or about the same height as the top of the sub. Any problems with vibrations from the sub causing distortions/waves on the screen?

4) One response on one thread suggested that front and center is typically NOT a good place to put the sub. Anyone have a link/comment as to why this is the case?

I'm considering this because putting the sub in the back, left, rear corner (my only other choice) is doable, but it is pretty tight. People will have to squeeze by the sub to get to the stair leading to the riser.

Thanks.

I saw someone post a HT layout that had the sub under the center channel. I've read a little about placing a subwoofer under the center channel, but I have a few more questions.

1) The previous threads said there was no issue placing the sub under the center channel. I'm not sure about what to do with acoustically absorbing material in this case. The sub would be under the center channel, behind the screen & false wall. Would you still deaden the wall behind the false wall in this case? Or is the sub frequency low enough that it isn't affected by standard deadening material like duct liner?

It is best to place the sub-woofer on a heavy material or subdude to absorb some of the energy if you are placing it this close to a wall. Having the deadening material on the false wall will really make a night and day difference for absorbing some of the higher frequencies the sub-woofer will put out. A crossover is not a brick wall therefore it is important to consider the frequencies above the crossover filter. I am not sure what thickness you would need to do this because I would need more info. I would guess multiple layers of that material would be needed. It can be very difficult in most situations to treat frequencies bellow 50Hz and this would very much apply to placing material directly behind a sub-woofer but it won't hurt to do so and is always a good idea.


2) What about bass traps? If you have bass traps in the upper front left and right corners would they affect the performance of a sub placed between them (though on the floor)?

Yes that will help a great deal to even out the response across the seating area. Your front wall can be most one of the critical areas since this is where alot of your imaging is coming from and corner traps will help to absorb a broad range of frequencies. What kind you will want to choose to use and what material used will depend on what will work best for your situation. I found after placing traps and having the subwoofer in the center the response was very identical at each of the seats left, center, right but this was not easy and most would call it just lucky.

3) The bottom frame of the screen would be a little lower and/or about the same height as the top of the sub. Any problems with vibrations from the sub causing distortions/waves on the screen?

I found with the subwoofer placed between some traps, in front of a trap and a 5/8 wall with insulation having a steel fixed frame screen will have the capability to still rattle. Examples are LOTR drums, Resident Evil Apocalypse bullet time scene on DVD. Thats it so far! This mostly depends on what style of sub-woofer you choose and how loud you like to listen. I will be getting a second sub-woofer soon and it will most likely be moved away from the wall some. As it is now the placement is about 5 inches away from a 2" bass panel then wall.

4) One response on one thread suggested that front and center is typically NOT a good place to put the sub. Anyone have a link/comment as to why this is the case?

Because when you place the sub-woofer generally the idea is to achieve maximum low frequency output, even response, and good interaction with room modes.

I'm considering this because putting the sub in the back, left, rear corner (my only other choice) is doable, but it is pretty tight. People will have to squeeze by the sub to get to the stair leading to the riser.

Thanks.It might also be very easy to localize the subwoofer in that back corner. Try and see what works best.

Hi Nikita,

If you can possibly do it, it's best not to commit the sub to a specific spot. It is better to commit only to an area by leaving the sub on several feet of cable. Finding the optimal spot for the sub is seldom a trivial task, and is often best done by trial and error.

To make this easier, you can use the principle of acoustic reciprocity -- swap places with your sub. You put the sub where your head would be for listening, and listen to (or measure) the subwoofer frequencies at possible sub placement locations. Because subwoofer frequencies are omnidirectional, it doesn't matter whether the sound waves are traveling forwards or in reverse.

Regards,
Terry