Question regarding rear speaker placement

[Tryguy]

Hi there, I am hoping that you guru's can help a newb. My new HT is projector-based (Optoma H31) and is all plugged into a Yamaha v540. The system is a 5.1 surround sound system. The room size is approximately 20' long and 12' wide. The most convenient and logical (doesn't mean right) spot for my rear speakers is hanging from the ceiling (due to the fact that the room is so long and there is so much empty space behind the recliners). The challenge is this, the spot where I would install the speakers is an HVAC duct covered by drywall.

The 2 questions I have are:

1) Is it okay for my speakers to be at the 7' roof height or should they be lower (and how would I lower them)

2) Will the HVAC reduce sound quality at all, even though it is wrapped in drywall?

Thanks for any help you can give.

 

[AVRat]

Is there any way the surrounds can be mounted on the sidewalls about 2'-4' behind the listening position and about 5'-6' high facing each other? If not, how much space is there to the back wall?

 

[Pyrrho]

First, take a look at:

http://www.dolby.com/consumer/home_entertainment/roomlayout.html

And be sure to read the text below the image.

Second, what you are saying will work, though it is not ideal. See link above.

 

[Tryguy]

Makes sense

Hi guys and thanks for replying. I guess my concern was that if I mounted the rears on the side walls that they would be too far away. The back wall is about 8' away from where the seating will be, so I think that is too far away. So I guess the trick is to mount them on the wall just above ear height and adjust the delay and volume accordingly?

Thanks again.

 

[Pyrrho]

Hi guys and thanks for replying. I guess my concern was that if I mounted the rears on the side walls that they would be too far away. The back wall is about 8' away from where the seating will be, so I think that is too far away. So I guess the trick is to mount them on the wall just above ear height and adjust the delay and volume accordingly?

Thanks again.

They can be far away. In fact, many recommend that the rear speakers be as far away as the front speakers (and with some SACD players without delay adjustments, with receivers that do not have delay settings for multichannel ANALOG inputs, it is NECESSARY in order for the sound to be right). Of course, all of this will affect delay settings and so forth, but those would need to be carefully adjusted in any case.

 

[Tryguy]

Thanks and for my next question...

Thanks for the help. In terms of delay and volume levels, is there a good guide out there to assist in setting the speakers up or do you guys just use your educated ear?

 

[MDS]

Thanks for the help. In terms of delay and volume levels, is there a good guide out there to assist in setting the speakers up or do you guys just use your educated ear?

You can do it by ear, but it will usually only get you close. It's much better to use an SPL meter with the internal test tones or pick up a copy of AVIA or DVE (calibration discs). The discs also have a decent introduction on how to do the calibration.

 

[Pyrrho]

Thanks for the help. In terms of delay and volume levels, is there a good guide out there to assist in setting the speakers up or do you guys just use your educated ear?

The delay is set based upon distance from the viewing position. That information is somewhere on Dolby's website (it should also be in your owner's manual, but it might not be). As for the levels, you can set it by ear, but you are not likely to get it accurately set. For that, a sound level meter is best (unless you have one of the newer receivers that does a good job of automatically setting itself). You can use the built in test tones of your receiver, or you can use a separate test DVD.