[bakufu]

hi all

the rear wall of my listening room is a 25x8 foot stretch of floor-to-ceiling windows.  my speakers, a pair of emerald physics cs1.3's, sit about 6 feet from that wall.

it's not clear to me whether all that glass is a problem that needs to be addressed, but i'm still thinking of going ahead and treating it.  the thing is, i love the view (onto a canyon), and i'm not ready to give it up in order to claim marginal sonic benefits.  curtains and drapes don't really harmonize with the style of the room (aggressively modernist) and the shades i've looked at strike me as having questionable acoustic value (but i could be wrong about this).

bottom line:  from a theoretical point of view, just how nasty a combination is glass + open-baffle dipoles?

thanks in advance -

[bakufu]

correction: i meant *front* wall, which the rear of speakers face.

[JohnR]

I suspect it's probably not as bad as you think. The Emerald Physics are only dipole up to some frequency and the glass probably reflects bass less than other wall types. I'd be inclined to do some measurements (see the ACoustic measurement standard in the acoustics circle) and to experiment with some absorbing material on a stand of some kind right behind the midrange cone.

[Russell Dawkins]

I don't know what your listening habits are - whether you typically listen alone or in the company of others, for example, but if it were me I would look into a semi near-field set up where the speakers were closer to me and farther from the glass. This keeps the noise level down in the rest of the house for the same listening level as a side effect.

Failing that, play with the angles and use the dipolar characteristics of the bass/mid to  your advantage. Position the speakers so the edges aim at three of the main first reflection points, if possible - the two side walls and the center of the front wall behind the speakers. Keep in mind there is nothing at all wrong with angling them inwards so they cross in front of your primary listening position, intuition aside.

I can understand not wanting to lose the view. I wish I had a great view as a backdrop when listening.

[bakufu]

thanks for the advice.

at this point i have little in the way of empirical evidence for my concerns.

i should have mentioned that the system is using clayton shaw's spatial computer room-correction software.

there are two variables at play here:  the glass wall, and the room-correction settings dialed in by clayton.  my thought is to start by hanging a few blankets on the glass wall just to see what audible difference that makes.  just something to approximate the damping effect of drapes or curtains.

i should be clear that i am in no way dissatisfied with the results i'm already getting.  the 1.3's replace a pair of apogee divas which had the same position in this room for a decade.  the divas were boomy in the bass, the sound-stage was smeared, and instrument positioning was all over the place.  by contrast, the 1.3's are astonishingly life-like, open, explosive, and (most important to me) the musical timing seems dead-on.  so further improvements will be (i expect) marginal.  but curiosity will not be denied ...

[THWO]

How about building two flat frames in about the size of your open baffles, at least up to your woofers, stuffed with thick absorbing material and, for optical reasons, covered with speaker cloth? Placed may be three feet behind your speakers, the should be virtually invisible form your seat and may already help quite a bit.

Regards
Till

[bakufu]

>How about building two flat frames in about the size of your open baffles, at least up to your woofers, stuffed with thick absorbing material and, for optical reasons, covered with speaker cloth? Placed may be three feet behind your speakers, the should be virtually invisible form your seat and may already help quite a bit.

that's a terrific idea.  thank you!

[JohnR]

i should have mentioned that the system is using clayton shaw's spatial computer room-correction software.

Do they give you the curves? It would be interesting to see them (just curious)

[zmyrna]

How about building two flat frames in about the size of your open baffles, at least up to your woofers, stuffed with thick absorbing material and, for optical reasons, covered with speaker cloth? Placed may be three feet behind your speakers, the should be virtually invisible form your seat and may already help quite a bit.

Regards
Till

I would make that a cylinder (equal height and width to your woofers) instead of a flat frame and experiment with the distance; I have a feeling it would sound best closer to the back of the speaker.

[bakufu]

>Do they give you the curves? It would be interesting to see them (just curious)

yes, but i want to postpone publishing any of that material until i write up my review of these speakers, which i plan to post here.

additionally, i'll be integrating a pair of subwoofers (from nathan funk) in a week or two, and at that point i'll be ready to do a final session with clayton.

[sfdoddsy]

I think any issue would be with the higher frequencies rather than the bass. I was faced with a similar problem in my old house and research (which I can't find) indicated that glass windows act like a large bass trap.

However, they do reflect higher frequencies.