Subwoofer room placement w/ RS Meter Q's

[NoDestiny]

Hey gang,

Im getting ready to do a home theater soon and have a few questions on the basic concepts and practice of subwoofer placement. Nothing specific, just questions in a general setting...

1. I hear people move the couch and place the subwoofer there instead of ON the couch, in the listening position. Is this a better way to do it?

2. Should the room have its furniture and such in place first, or will you get a pretty accurate reading with an empty room?

3. Should the room have its acoustic treatment done (such as bass traps) installed before doing the reading? Or do you want to capture the room in its natural response?

4. Should the mic be aimed in any specific direction when trying to find that sweet spot (and graphing the ~10-150Hz range)? What about when installing flush mounted or manifold style (such as infinite baffle), should the mic be aimed at the wall or any specific direction?

I think thats my 4 main questions. I have never actually done anything more than just throw the sub in the listening position and crawl around with something like Bass Mekanik playing everything from low to high. Want my future install(s) to be more accurate and scientific than that!

Thanx!

[NoDestiny]

I realize some of this maybe getting carried away, but I like trying to get things right the first time. If anybody has input, it would be appreciated.

[daniel-a]

The sub goes where you usually sit.
You don't move the couch. In fact, you don't move anything, but yourself.
Your room should be as it will be when you're set up is finally done.

[Wayne A. Pflughaupt]

I have never actually done anything more than just throw the sub in the listening position and crawl around with something like Bass Mekanik playing everything from low to high. Want my future install(s) to be more accurate and scientific than that!

You’re right, not terribly scientific or accurate.

Your cheapest route would be to get a SPL meter and graph paper, and plot out 1/6-octave frequency response graphs of your subwoofer response, at all viable locations in the room measured at the primary listening position. You can probably Google and find some sine wave tones that you can download and burn to a disc. The location with the fewest peaks and valleys is what you’re looking for. However, I would recommend getting a parametric equalizer like the Behringer DSP1124 to smooth out response even better once you’ve found the best location.

1. I hear people move the couch and place the subwoofer there instead of ON the couch, in the listening position. Is this a better way to do it?

Probably on the couch would be best. As you probably know, this is the equivalent of measuring at the listening position and moving the sub to different locations. With the “couch” method, the sub stays put and you take the measurements at the various proposed sub locations.

2. Should the room have its furniture and such in place first, or will you get a pretty accurate reading with an empty room?

With subs it shouldn’t matter a whole lot, but there’s no good reason not to measure the room in the state in which it will be used.

3. Should the room have its acoustic treatment done (such as bass traps) installed before doing the reading? Or do you want to capture the room in its natural response?

As above – measure the room after everything you intend to be in it is in place.

4. Should the mic be aimed in any specific direction when trying to find that sweet spot (and graphing the ~10-150Hz range)? What about when installing flush mounted or manifold style (such as infinite baffle), should the mic be aimed at the wall or any specific direction?

In all cases, it matters little.

Regards,
Wayne A. Pflughaupt