Retail Store. Speaker Placement Help.

Hi Jazz B,


Mounting all speakers on the short walls 4-5 feet from the corners, (with the room being approximately 3 times as long as it is wide) will concentrate more sound at the ends of the room leaving a bit of a "hole" in the middle; the speakers would be approx 9' apart from each other on the room's short walls but 55' apart down the length of the room.


For more uniform sound distribution, mount 2 of the speakers near the corners BUT on opposite long walls and mount the other 2 staggered down the long walls, as follows: (consider the long walls as N and S...and the short walls as E and W)

1st speaker - mount on N wall at approx 7' from the NW corner

2nd speaker - mount on S wall at approx 21' from the SW corner

3rd speaker - mount on N wall at approx 34' from the NW corner

4th speaker - mount on S wall at approx 48' from the SW corner (i.e. 7' from the E wall)

(Simply: length of the room divided by speaker quantity and staggered across the room evenly from the end walls and down the room. With 4 speakers to utilize, the fact that the room is so narrow in relation to the length contributes to the speakers being much closer to each other.)


Yes, the omnipolar design should be mounted upside down. With that said, the Mirage FX model (I have Mirage OMD-5's and OMD-15's at home) appears to be a reasonable-quality speaker. But in a room the cubic volume (LxWxH) of yours and mounted at 16' AFF (above finished floor), there will be limited output volume and bass at listener level. Nonetheless, without knowing what model your ceiling speakers were and where they were located in the ceiling, I'd still guesstimate that the new sound will be lots better...and more evenly dispersed


Cheers.

I was going to recommend installing your speakers equidistance along one of the 55’ walls at ~9 ft. intervals, as that would get the best (read most even) coverage throughout the room given the narrow dimensions.


But then I noticed that you’re going to mount them 16 ft. up, so I don’t know. Wall-mounted speakers would sound best at ~8-9 ft high.


Your salvation might be the Omnipolar technology, so yes they should be inverted. (Actually, any speaker installed more than a foot or so above head level should be inverted.) However, the bracket the FX’s come with might preclude inverted mounting? I don’t think corner placement would work well unless you can get them tilted downward, and again I have my doubts that the stock bracket will permit this. As tadcu noted, a "hole" in the center of the room is a highly possible situation.


Four better-quality ceiling speakers, evenly spaced front-to-back I think would be a better option and give the best (again, most even) coverage. I can’t imagine why you’re getting a “beaming” effect with your current ceiling speakers. That shouldn’t be an issue with ceilings as high as that. Maybe you just don’t have enough of them installed to provide even coverage?


Other considerations: The speakers should be fed a mono signal. Stereo does not work in background commercial situations.


Also, if you were using ceiling speakers, they are typically 70-volt. If that’s the case, your Mirages won’t work with your current amplifier unless it has an 8- or 4-ohm output. And you’ll have to make sure you configure the speakers for the correct impedance load.


Regards,

Wayne A. Pflughaupt

Jazz B.,


It's probably of minor concern at this point, and while respecting Wayne's valuable comments, standard commerical sound system design is that speakers should be half the distance from the end walls as they are from each other. In layman's terms: this is because speakers propagate their sound to the left and right sides (as well as top and bottom). So, placing the 1st speaker approx 7' from the end wall with it's sound progating 7' to each side means it "meets" the edge of the sound from the next speaker that's placed 14' away.....and so on.


And, as Wayne said, normal system design does indicate wall-mounted speakers should be located considerably lower than where you said you have to mount them.


With regard to stereo/mono: again standard commercial design indicates, as Wayne noted, that it should be mono. Yet, with your room proportions and a high mounting location, a stereo configuration could actually work out without a listener hearing only "half the music" (designer jargon meaning only one of the stereo channels). You would alternate the R and L channels as you progress down the room.


An appropriate stereo amplifier (i.e. one that is "happy" living with a 4 ohm load or even lower), could mitigate the usual requirement for a 70V commercial amp. I'm assuming, perhaps incorrectly, that you're on a budget.


In the commercial A/V integration world, we would not normally make the above suggestions with regard to consumer amps and stereo but in reality I've observed and heard dozens of sound systems with consumer amps (as long as they are robust models that can handle low impedances) and some with stereo layouts that work out well in rooms similar to yours. Where commercial 70V amplifiers (almost always mono) are really necessary is when/if you need an odd number of speakers or more than 4 speakers, when you need different types of speakers in different areas, when you need to control the volume separately in different areas and other design considerations.


Best regards to you both.