Soffit mounting?

AVare wrote:

One strong suggestion is to create one thread on one site with all your main questions for your room. Trying to keep track of what was posted on one site and replying on another with that information is a daunting task. Andre

Understood. I normally try to do that, but it seemed to fit here, since this is like the mother of all Soffit mounting threads. Hopefully others can benefit from the clarifications. Back to your originally scheduled program, folks. K

You are welcome. I was debating in my head which, if any link to provide for further information when I remembered that you enjoy knowing the complete truth. That made it then just a question of how technical an answer to link to. The JBL doc is geared towards sound reinforcement, but the underlying principles are the same in control room design. I hope you enjoy it. Andre

It is GREAT André! I actually do a fair amount of sound reinforcement as well, running live sound for events, so that JBL document is really useful. And yeah, I sure do enjoy knowing the complete truth, and understanding the theory behind the practice! So thanks a million again!. Like you say, the document is a bit technical, but nothing too complex by the looks of it, and a lot of it I knew already- But there are always new gems to discover, always the possibilty of learning something that you didn't know before. I'm really enjoying working my way through it! :) -- Stuart --

Soundman2020 wrote:

But there are always new gems to discover, always the possibilty of learning something that you didn't know before.

That is so true. Once you know the basics, a lot of documents are "variations on a theme" or developments based on the basics. The PSSDM is in two parts. The second part is in the same general area of the url. The big thing that I learned from the PSSDM was when working with absorbent materials not only to think of what is absorbed, but of what is reflected! A mind think I see very rarely mentioned in acoustic treatment. Thank you George Augsburger. Andre

Thanks again, Andre! I found, downloaded, and read that second part. I'm curious about their recommendations for room EQ, on page 6-17, graph 6-17 "B". Why would you want to have a 3dB/octave roll-off above 1kHz? I guess I could almost understand it if they are only talking about systems for speech, but I can't see the logic of doing that for music. Could you shed some light on their recommendation? Anyway, the good news is that my Adam A7s and SUB-8 finally arrived last week, so I'm looking forward to playing with them this week! :)

Soundman2020 wrote:

I'm curious about their recommendations for room EQ, on page 6-17, graph 6-17 "B". Why would you want to have a 3dB/octave roll-off above 1kHz? I guess I could almost understand it if they are only talking about systems for speech, but I can't see the logic of doing that for music. Could you shed some light on their recommendation?

The section is dealing with the obsolete method of using a RTA type measurement tool and compensating for the reverberant field which is dominated by the power response of the speakers and the acoustics of the space. Modern sound re enforcement systems are equalized using FFT analyzers which permit looking the direct output of the speaker system, not the direct and reverberant field combined. The paragraph on the bottom right of the page may make more sense now.

At the point in the house where the measurement is made, the reverberant field At the point in the housepredominates, and what we are shaping with the equalizer is actually the power response of the loudspeaker as influenced by boundary absorption in the room. If the loudspeaker’s power response is smooth to begin with, then all is well. However, if, as in some older designs, the system’s power response is irregular, then equalization will usually make things worse,

Anyway, the good news is that my Adam A7s and SUB-8 finally arrived last week, so I'm looking forward to playing with them this week! :)

[/quote][/quote] Fantastic! Let us know how they sound! Andre

Fantastic! Let us know how they sound!

Finally a chance to try them out! They sound pretty good, actually. Not totally what I expected, but that might be because I have them sitting on top of cardboard boxes on my dining room table.... :) But seriously, considering the way I have them set up, they sound great. I listened to some stuff that I'm working on, and realized just how bad my mix was! But I'm really looking forward to hearing how they sound encased in concrete soffits, a few months down the line! However, for now they'll have to go back in their nice snug cardboard boxes, and back on the shelf... Sigh! :( - Stuart -

Soundman2020 wrote:

Fantastic! Let us know how they sound!

Finally a chance to try them out! They sound pretty good, actually.

Congratulations. Merry Christmas from your friend in the other hemisphere. Andre

Hi, after reading all the post in this topic and did some intense research in the rest of this forum I still have some open questions about soffit mounting monitors: 1. Many people say: The Monitors have to be set on a very heavy base - some suggest to use “conrete”- and to completely detached this base from the rest of the construction. - I don´t see that in any construction drawing on this site (for example the SAE-Drawings)! So no heavy base is OK too? 2. Also many people say: “The front-wall has to be huge and heavy” - In many construktion on this site, a solid wall is only at the sides and above the monitors. Below I see insulation coverd with cloth. So, no solid wall under the Monitors is OK too??? A wall that is not surrounding the monitors is OK??? 3. Maybe a stupid question: If you use aktiv monitors and put them in the wooden box. Wouldn´t it be enough to just have an opening at the top of the box, so the warm air can flow upwards? Is an additional opening at the bottom of the box indispensable? I would be very happy if someone could help me with these questions. Regards, Lars

Lars, in the period before anechoic chambers to test a speaker they went and buried it in the ground so the speakers were flush with the ground. They then hung a mike over it and recorded the response. They only wanted the response for the speakers, not the box's additional problems such as reflections that interfere with the phase of the low end and alter the response. Soffit mounting does the same by creating one plane from which the speaker radiates into the room.

Thanks for your reply John. But that is exacly why I ask my (first two) questions. So most of the constructions I see on this site (like in the SAE-Pictures) are all wrong? I guess not. I guess they are just a good compromise - am I right? Lars

I'm still learning about soffits, Lars, but from what I get so far, the soffit panel acts as an infinite baffle. Obviously, truly "infinite" is impossible, but as long as the panel "appears" very large acoustically, in relation to the wavelengths of the sounds coming out of it, then you approach the same effect. So you want your speaker in the center of a "large" massive panel, as similar as possible to the "buried in the ground" scenario that John mentioned. But as you mention, there have to be trade offs. Not even the largest studios can afford to have each speaker mounted in the center of a baffle that is even one full wavelength at the lowest end of the spectrum. You'd need a room at least 34 meters high and well over 70 meters wide to do that! Apart from the expense, that would be a highly impractical room! The way I understand it, fortunately the trade offs are not that serious until you get down to fractions of wavelengths in the mid-range. I haven't looked for the reason behind the number, but I do seem to recall reading in several places that a 48 inch (or was it 45?) baffle (soffit panel) is a good compromise. Of course, as you'll see many people mention here, "You have to live with what you have". If you can't fit 48 inch panels in your room, then just make them as large as you possibly can. Even a small baffle will help to some extent. I guess there is a dimension where it becomes pointless (diminishing returns), but I'm not sure where. For example, I guess a 2 inch baffle would be basically useless! :) Also, John often uses the space below the panels (which is generally behind/under the desk), for bass trapping. I guess that's because it doesn't make much sense to extend the baffle down that low, as it will be in the shadow of the console. But I'm just guessing there: John can certainly explain it much better than I can! I'm just making assumptions here. Hopefully, they are reasonably accurate! - Stuart -

Hi Stuart, thank you, that is a very comprehensible explanation to my ears. I am very curious what John will say about that. Any opinion on my third question (see above)? Lars

Stuart - the baffle extends below the speaker apart from a low port at the join with the floor to allow access for the sound into the space behind the lower baffle where the trap is. I cover the lower baffle with absorption to stop reflections off the rear of the console unit from coming back at you delayed.

Ahhh! Ok, thanks John. Now I get it. So I need to do some re-design on my panels, to extend them much lower. One question: I'm assuming that the "air space" behind the baffle (between baffle and front wall) does not need to be sealed hermetically? Or am I wrong on that? - Stuart -

no it doesn't have to be sealed Stuart.

Hi all, Two questions! I saw that "lurion" asked (page 4 in this thread) about soffit mount speakers with bass reflex port at the back, anybody outhere know if it has been tested? Results available? except, [quote="gullfo"]check on the construction forum - there's a number of folks who have built soffits which are open enough for rear ported speakers - Kendale, Djo, Giles, etc.../quote] See john pics on Page 3 in this thread, If the cavities behind soffit/Bezel and around the speaker have hangers and or super chunks, would this not reduce the need of the -6dB filter (given soffit concept?)

I am just about to decide wether to soffit mount Behringer 3031A or not. I am anxious about a couple of things: 1) Is there a way to combine superchunk corner trapping and soffit mounted active monitors? 2) Is there a need to create a whole plywood board for the "face"? Using wooden slats would probably not work at all, right? 3) Anyone tried soffit mounting Behringer active monitors? Thanks in advance!

1) Is there a way to combine superchunk corner trapping and soffit mounted active monitors?

What is Superchunk? Edit: Never-mind, all this NEW terminology for OLD things. Corner built soffits combined with angled Slat Resonators provide the purpose of a "Superchunk" in the front your control room.

3) Anyone tried soffit mounting Behringer active monitors?

Lowlife. the key to making your Behringers work is in the Low Frequency Setting. You will need to play with that setting to find the best bass position. I would gander it would be at -6db 2nd. make sure you have the circulation as shown in the soffit design. Extremely important else you WILL run into overheating problems.

2) Is there a need to create a whole plywood board for the "face"? Using wooden slats would probably not work at all, right?

Yes you NEED to do the Plywood face. No air gaps (aside from the ports shown) The slats are for decoration.

What is Superchunk?

It appeared since you were last here Brian - it's where you cut out a corner shape in insulation and then stack them on top of each other to completely fill and area with solid insulation.

John Sayers wrote:

What is Superchunk?

It appeared since you were last here Brian - it's where you cut out a corner shape in insulation and then stack them on top of each other to completely fill and area with solid insulation.

LOL. Yeah, I figured that out. LOL. Sorta Like an AuraLex Lenrd, But it actually works. lol.

Hey there, I read this entire forum and couldn't find my answer ,I'v just realized im going to run into a problem mounting my HS80'S in the soffit mounting style ... How do i turn them on if the switch is on the back ? I feel like that's an ignorant question im just stumped. Thanks -Jeremy

Easy, make a new switch outside of the soffit and connect it through there. Keep the switch on the back of your speakers ON. :)

j.clarke wrote:

Hey there, I read this entire forum and couldn't find my answer ,I'v just realized im going to run into a problem mounting my HS80'S in the soffit mounting style ... How do i turn them on if the switch is on the back ? I feel like that's an ignorant question im just stumped. Thanks -Jeremy

The other thing you can do, is remove the amplifier from the speaker, extend the wiring and mount it in an easily accessible location.

I had considered both of your suggestions. I do have one question about removing the amp though. Would that possibly affect the performance of the monitor.... John had said on here they used to test speakers by placing them in the ground then putting a mic above them. They probably kept the amp and speaker together when they did this , assuming there active. ? Also, if i take the that back panel off , i wouldn't need any air circulating threw my soffits would I ? There's a heat sink on the back that is attached to that panel btw ... I'm sure you already know that ( just trying to be clear) Thanks for the quick response -Jeremy

Which speakers are they again (w/o) me scouring your post....