Are Wilson Sophia 2's lean in the midbass?

Shadorne,

Could you explain what you mean by soffit mount? I think of a soffit as a projection between a ceiling and adjoining wall. In kitchens, cabinets are often hung from soffits.

db

Soffit means the speaker is mounted in a wall with the baffle flush to the wall. It means that the speaker radiates only into half-space - 180 instead of 360 degrees.

It improves the bass response (which is omnidirectional below 600 Hz) by removing the reflection of the speakers from the wall behind the speakers.

In simple layman terms - imagine the wall behind your speakers as a mirror. Now you see FOUR speakers from your listening position and that is exactly what you are listening to in a normal free standing speaker setup: two real speakers and two "image" speakers that are reflected by the wall directly behind them (what you actually hear is called a "comb filter" or a series of sharp suckouts in frequency response gradually decreasing up to around 600 Hz, at which point the speaker only radiates forwards and the problem goes away).

Now imagine the speaker baffle is built flush into the surface of the mirror just like these are flush with the wall Soffit Mount - now you hear only TWO speakers as there is no reflection.

Now you should have an inkling why as little as 6 INCHES of speaker movement in a free standing speaker setup makes a HUGE difference in the bass - this is because the reflected speakers move position and this changes how they reinforce or diminish the sound coming from the real speakers - in essence the teeth of the comb filter move around as you change speaker position. The important point to observe is that is does not matter where you sit - the interference from the reflected speaker will affect the bass response over the ENTIRE ROOM. All you can do is try to mitigate this effect by employing other reflections that are also occurring in the room to try and even things out a little. The comb filter suckout effect is made worse in that it is harmonically related which can really kill certain notes moving the fundamental AND the partials....

notes moving the fundamental AND the partials....

I meant REmoving - sorry my typing is always so bad...

Shadorne said, "Now imagine the speaker baffle is built flush into the surface of the mirror just like these are flush with the wall Soffit Mount - now you hear only TWO speakers as there is no reflection."

Yes that is true. But you still hear the reflections from all of the other walls, including ceiling and floor. Therefore bass and broadband absobtion is still necessary.

Bob

I've never heard any Wilson speaker sound lean. I'd agree with the room issue crowd. The same room issues may affect different speakers differently, explaining why Wilsons seem "leaner" than others in the same room.

Other speakers may excite the room differently, because they load it differently. IME, you'll usually find significantly elevated reponse in the half octave above 70hz to 100hz (above the 1/4 wave suckout mentioned by Shadorne) in most rooms. The specific frequency combination of suckout and "hump" differs from speaker to speaker (and placement of the speakers) and determines the perceived nature of bass anamolies for that speaker/room combo. That's why the Wilsons may sound "lean" while some other speaker sounds "thick".

If you don't want to soffit mount your speakers, you might want to think about Hemholz resonators (bass busters) and/or room correction/EQ'd subwoofers. Ironically, by absorbing bass (below app 125hz, the real problem area), bass busters can actually cause some speakers to sound a bit "fuller" as the mid to upper bass comes back into balance.

Good Luck,

Marty

Yes that is true. But you still hear the reflections from all of the other walls, including ceiling and floor. Therefore bass and broadband absobtion is still necessary.

Bob

Absolutely! Great point.

However, in the particular example I gave, the "symmetry" is what makes it one of the more severe or dominant reflected effects in most rooms.

Floor reflections were studied years ago and it is one of the reasons that down firing subwoofers are recomended (to try and get rid of that midbass suckout from reflected energy cancelling the primary bass signal). FWIW: if you have a subwoofer then an asymmetrical placement may prove best - it is the symmetry that will give you the sharpest and deepest suckouts...