Soffit mounting?

John, I know this has probably been discussed to death elsewhere, but I want your opinion for an Acoustics FAQ I'm preparing. Years ago when I built a pro studio, our acoustic consultants were clear that soffit mounting was preferred. It certainly makes sense to me, to minimize the nearby reflections that cause comb filtering and similar artifacts that occur at low frequencies. But I have seen photos of a lot of rooms where the loudspeakers (sorry, monitors) are just standing in the room. So what do you think? Have you any experience with a room that had one type of mounting and then changed to the other? Are there any scientific reasons why soffit mounting is not better? --Ethan

Well as you know I always recommend soffit mounting Why? because I've heard it work so many times. I've had clients who know their speakers really well and when they hear them soffit mounted they look at me with amazement!! "what these are the same speakers??" Ive done it with all kinds and had only one that didn't work - a set of JBLs that had so much low end boost already built in they became woofy. The client replaced them with another model of JBL and they were great. As a mix engineer I find a good set of powerful soffit mounted speakers act like a magnifying glass. You can blow up the kick and bass and hear how they blend. The imaging is always truer also (more than nearfields). When mixing I often turn them up and go and make a coffee whilst listening to the bottom end. Much more is revealed and you know that when some DJ turns it up at the club the low end will be tight and true. cheers john

John, > I always recommend soffit mounting < Yes, I agree that the explanations in favor of soffit mounting make sense. I don't know why some people say otherwise, but your opinion matters a lot to me. Thanks. --Ethan

What is soffit mounting? :( Thanx

Ethan - who exactly says otherwise?? The only major studios that I've seen that Don't soffit mount are the mastering suites and they use different speakers like Duntecs etc. and whilst we (mix engineers) are worring about the trees, they are more concerned with the forest. :) DBX160 - soffit mounting is where you install the speakers in the wall so the front of the speakers is flush to the wall. It eliminates the speaker radiating in 360 degrees in the low frequencies. It looks like this: cheers john

I gues this would not be a good idea for my active Mackies though? :?

I'm not sure about you Mackies Myke - they sound really big in the low end so I suspect thay have a low end boost in the works. But I'm not sure what adjustment they have on the rear to compensate the low end. cheers john

The Mackies have bass compensation controls for Full (open room), Half (against a wall), and Quarter (in corner). The corner is the biggest roll-off of low end as it assumes the bass boost of a corner placement. Don't know how it would translate to soffit mounting though.

If that's the case I'd give it a go. When we were building Left Bank Studios we were waiting for the Genelecs to arrive but being the impatient bugger I am I had to try something so we put the Event 20/20bas speakers up into the cavity. They sounded fantastic, (some felt better than the genelecs ;) ) so I'd give it a go. cheers john

Oliver - I moved your post to the Speaker forum for Barefoot to answer your question. Hope you don't mind ;) They sure seem to get good reviews. cheers john

Yeah, I've been thinking about soffit mounting and two points occur to me regarding actives (ie Dynaudio BM15a's) The plans for installing soffit mounts on the SAE site say the box should be almost airtight. Wouldn't this make the monitors overheat from the heatsinks on the bacK? As the monitor would be set into the wall you wouldn't be able to turn them on or off. Could you leave them on or could you turn them on and of from the mains lead in the wall? Thanks!

oliver - I wrote the SAE stuff back in '98. :P You can still soffit mount if you allow air passage behind the speaker like this. cheers john

I see. What about powering up the monitors. Is it safe to do this remotely from the wall outlet? Does the 60 degree monitoring system still apply if so does one just hang as many acoustic hangars underneath as space allows? Many thanks Oliver

I don't see a problem powering up from the mains switch. Perhaps you should check with barefoot in the speaker forum. 60 degrees is the standard angle, but I have used 90 degrees with equal success. Yes the hanger numbers are determined by the size of the cavity. Have you managed to post a drawing of your room. If you can't do it send me the dimensions and I can draw and post it for you ;) cheers john

Sorry to Jump in here but John when you say 90 degrees are you implying a set up like this?

No - like this cheers john

I've nearly done the drawings, John. I'll post them today. Ta!

Doesn't mounting the monitors so close to the corner this way cause problems with early reflections from the side walls? :(

Yes but you splay the walls with more angle, i.e. at 22.5 degrees as opposed to 12. I find it helps where you have a small room and the 60 degrees doesn't give you much width between the speakers relative to your sitting position. Music Farm studios http://johnlsayers.com/Pages/Music_Farm2.htm was built as a 90 degrees system. I worked there for years with and loved it. It was one of the best sounding rooms I've ever worked in and other engineer/producers recorded top selling albums out of this room. cheers john

John, I have a couple of questions about the speaker section drawing on page 1: 1) What are "acoustical hangers"? 2) Why is the area below the speaker not boxed in with 5/8" plywood and timber finish like the area above the speaker? Is this area performing as a bass trap? Thanks! Scott

John, I have a couple of questions about the speaker section drawing on page 1: 1) What are "acoustical hangers"? 2) Why is the area below the speaker not boxed in with 5/8" plywood and timber finish like the area above the speaker? Is this area performing as a bass trap? Thanks! Scott

The front is finished in an absorbing surface. I do this because it stops reflecions from the back of the console etc. coming back at you. The acoustic hangers are sheets of soft fibreboard, wrapped in insulation and hung - yes - they act as a bass absorber. cheers JOhn

What thickness is the fibreboard?

Its 1/2" (12mm) Oliver. cheers john

and what thickness of insulation? Would the rigid fibreglass be best? Cheers oliver