How do you chose speakers based on room size?

For best imaging and soundstage, you want a tight driver configuration that approximates a point source in smaller room with more a more nearfield listening configuration.

Planars, line sources, etc. with larger sound emitting area can work well in larger rooms listening from farther away.

Also, larger bass drivers in general or possibly a separate sub woofer will be needed to get a fulfilling low end in larger rooms.

Also, many speakers image best with more room to breath around them (distance to walls) so never try to cram too large a speaker into any particular space.

That's the jist of it regarding guidelines I can think of.

Some vendors, like OHM Acoustics, explicitly scale their drivers up and down in size for similar optimal sound in specific room volumes that they specify on their web site..

As has already been stated, small rooms are problematic. The smaller the room, the more important that acoustic treatments become.

A few rules:

The listening position always needs to be at least 18" from the wall behind. Less than that, and the low frequencies there will smear the sound.

The distance from the speaker front to the listening position needs to be around 9' to give the sound time to integrate. Less space is OK for single driver speakers since the sound is integrated to moment it leaves the driver. This distance really depends upon the distance between the drivers, but 9' is probably safe for most speakers.

Some speakers need to be out from the wall behind. This is especially true of dipoles - planars and electrostatics. These need about 4' from the wall behind. This is so the sound coming off the back will integrate with that coming off the front.

Other speakers seem to be at their best shoved up against the wall. This seems to be the especially case with BLH designs.

Given these parameters, we can see how a small room may become a problem depending upon the speaker. If the speaker needs 4' from the wall behind, and we need 9' for integration and the listening position needs to be 1.5' from the rear wall, we have a total of 14.5'. Obviously, if we do not have that, we may have a problem.

We really cannot do anything about the 18" off the wall behind the listening position. That is a given. The options then become a). selecting speakers that can be placed close the the wall, b) using single driver speakers that require less space for integration or c). a combination of the a) and b).

I am using Klipsch Chorus II in a room that is 10.5 by 12.5'. These are 3 way speakers with a 15" bass driver. This works because these can be placed close to the wall behind. I have space for the 9' of integration and for the listening position to be 18' off the wall. My room has extensive acoustic treatments. Actually, my experience has been that once I had the room under control, whatever I put in there sounded pretty darned good. Before the treatments, it was an echo chamber.

Hope this helps.

It costs a lot less to get a great sounding system in a smaller room. Its not that complicated. Smaller speakers + lower power amp typically brings the cost down a lot (except for Magico). And fewer room treatments if you decide those are necesary.

Hi Duke,

Have you ever tried DSP as a "room" or perhaps, more appropriately - system treatment?

Thanks!
Sam

J Bailey, your experience with the large-format Klipsch Chorus II's in a relatively small room makes sense to me. They probably benefit from generous boundary reinforcement, and are directional enough to avoid the onslaught of early reflections that one typically is met with.

C1ferrari/Sam, regarding DSP, once in a large room (ballpark 80 feet by 120 feet) we used DSP as a "room/system treatment", and it was definitely an improvement. My speakers didn't have adequate bass output in that size room especially with the positioning we had to use, although they did have enough excursion capability to handle the EQ. A rather sophisticated prosound DSP package was used, and we spent about an hour taking measurements in a wide variety of microphone positions.

Also when Robert E. Greene (of TAS) had a pair of my bipolars in his room some time ago, he experimented with at least one DSP room-correction system (something he is quite fond of). He reported in his online forum that the DSP correction made very little change to what the speakers were doing, which he said was indicative of good in-room behavior.

Two things that DSP cannot do anything about are the loudspeaker's radiation pattern and physical limits (both thermal and mechanical). So to get the most benefit from a DSP-corrected system, in my opinion it's a good idea to start out with speakers that do a good job in those two areas.