Surround question...

[CoolCat]

Yeah, see, I thought about that too. Will the entire wall reverberate from the music played through the speaker? Maybe. But keep in mind these are REAR SURROUNDS. They wont be used for day-to-day tracking and mixing. In fact, I'd expect they get used only about 10% of the time. And 8% of that'll just be me showing off!

i too...like the pics ...

i'm curious...so you don't think music is going surround? i might disagree, on the low usage of the rear speakers you projected.
I think your ahead of the game actually by doing it during construction.

i think more and more future recordings will be in surround and then some....whether the old audioheads like it or not....and no i don't want to replace my Beatles colleciton in surround sound.

the rears should offer you some versatility if nothing else...and why not add more surround stuff....it means more speakers, cables, and gearhead sht!!!whooohooo!!

seriously you outta hear that Blue Man group my kid listens to...wrap-around in a serious, pleasent way. great audiophile type stuff. its not coming its here.

Me i been enjoying listening to Let It Be..Naked.

 

[RICK FITZPATRICK]

Hello Michael, this is just a plan, and I don't have time tonight to zoom in on the details. I'll post more tomorrow. Got to go to bed.

The soffit box is mounted to the backwall. It does NOT touch the baffle face. The speaker box EXTENDS through the wall BAFFLE PANEL, but does NOT touch it. There is a 1/4" gap, between the speaker box and the edge of the baffle panel. The soffet box is set back 1/4" from the baffle panel also. I'll post details later. And a vertical section.

But in reality, this raises some questions regarding iso. AND I drew this as though there was an RC and 2 layers sheetrock. Later.
fitZ

 

[knightfly]

Cool drawing Rick - a couple of changes necessary though - you stated the specifications perfectly, as to what can/cannot touch what.

The changes -

1. the 120 degrees Michael mentioned is actually the rotation from front center to each surround speaker's axis of propagation - the actual recommended spec is 110 degrees plus or minus 10 degrees. I'm not sure if that's what you were trying to do with the extra angled baffle in front of the front wall section, or??

2. The 2020's have an 8" woofer, so should have a minimum of 4 x 8 or 32" from center of cone to edge of baffle extension, more would be better. Don't quote me yet on that part, I may have misunderstood Barefoot as to that requirement. The baffle extensions DO have to be pretty rigid though, so they don't re-radiate anything. 1-1/4 ply with a layer of MDF laminated is NOT overkill here, at least for mains.

Your CAD drawings actually translated pretty well for JPG's - what are you using for conversion?

 

[Michael Jones]

It is 110 degreees.
I just couldn't remember.

2. The 2020's have an 8" woofer, so should have a minimum of 4 x 8 or 32" from center of cone to edge of baffle extension,

See, that's where you're loosing me. What are you calling the baffel extension, and where is it in Rick's dwg?

 

[DDev]

I think I know the answer to one of these questions (about time)!!

Michael - I think the baffle extension is the bright blue/thick line that extends from the edges of the speaker where it comes into the control room, making an extended flush surface with the face of the speaker cabinet.

I'm beginning to visualize what Barefoot had described that totally confused me before.

Darryl.....

 

[Michael Jones]

I think I know the answer to one of these questions (about time)!!

Michael - I think the baffle extension is the bright blue/thick line that extends from the edges of the speaker where it comes into the control room, making an extended flush surface with the face of the speaker cabinet.
Darryl.....

OK. After a little more thought, that's what I was thinking it must be.

I think I can "recover" from this pretty easily. I just need to notch out the 2x4 on the right hand side of wall, and then build a little "tower" in there between the walls and canti-leaver out a "shelf" to hold the soffit (the little cab I show in the pic.)
Where the shelf on the tower canti-levers out, to penetrate the CR wall, I'll just fabricate a gusset plate to relieve some tension on said shelf.

Then the baffle extension can extend out along the wall...

pheww!

Seems kinda anal, but if I did it the way I have it now, and it didn't work... I'd be sad.

I wanna do it right the first time.

 

[knightfly]

Sorry, Michael - sometimes I forget to define terms. Darryl's right on, the "baffle extension" is the "fake wall" that is built to be flush with, and on the same plane with, the "baffle" of your speakers, which is the flat board that's the front of the speaker box, the one with the holes cut in it for mounting the speaker drivers.

The "soffit", which is more correctly (in this country, at least) called a "flush mount", is also referred to as a baffle extension, because that's what it does. It extends the baffle (front speaker mount board) of your speaker box in order to prevent lower frequencies from "wrapping around" the speaker and radiating full sphere instead of "hemisphere" -

This is why the part of the wall into which the speaker is flush mounted needs to be several diameters of the woofer, in any direction from the center of the woofer, so that the lowest frequencies that particular woofer can handle will still be a short enough wavelength not to "wrap around", but instead be forced to only radiate in the forward hemisphere.

This is the main reason for flush mounting, so it's best to keep that portion of the "fake wall" big enough to do its job.

BTW, just re-read Barefoot's comments on this and he does NOT recommend filler at the front but DOES recommend a tighter gap (between speaker box and front of flush mount) of no more than maybe 5mm (0.200") - theory is that highs don't need the extended baffle due to short wavelength, and lows won't see that small a "crack".

Hope that helped, be sure to check out my earlier link to Barefoot's thread if you haven't already... Steve

 

[RICK FITZPATRICK]

Ok guys, I know I haven't got every detail exactly right. This was only supposed to illustrate the concept. However, as I drew it, MANY unexplained details began to appear. Especially as I drew the Vertical section. Michael, please do not take this as exact geometry, although I did overlay it from your plan. But let me tell you, that "Baffle Panel"(blue) would be one hell of a mitering project, as there are adjacent angled walls, and the panel is angled, not only vertically, but horizontally as well. There is NO way in hell to draw an elevation of this panel, UNLESS I had every single existing dimension of the room. Or at least that area of the walls. I would LOVE the chance to "CUT TO FIT" as I think it would look FABULOUS within the geometry of your room. Various problems crop up though. For instance, since the Speaker Box is angled in two directions, make it impossible for the "BAFFLE PANEL" to be symetric in all directions. AND I seriously doubt if you could get 4 times the speaker cone dimension on one of the sides. Maybe 2 times MAX. My personal observation is, since this is an "after the fact" design element, there is no way to meed all the criteria, unless the room and walls were designed with this in mind in the first place.

WITH THIS IN MIND, I've done the best I can to illustrate it, at least enough to observe the associated problems. Go with it if you will. Just remember, this is ONLY an exercise on my part. Here is the Vertical Section and a "PSUEDO" detail. To actually achieve Barefoots criteria, brings up a whole new set of tolerance and dimensional construction problems to solve. GOOD LUCK> hahahahaha!!

(tape starts in background) whirrrrrrr.........."Mr. Jones, if you should choose to undertake this mission.......you are reminded that under no circumstances can you BLAME ME for this mess!!!..........(smoke comes from portable tape deck as it disintegrates) shsssssssssssssssss.............



fitZ

oops I have to put the detail on another reply, sorry.

 

[RICK FITZPATRICK]

Also Michael, with no absolute dimensions of the speaker box, etc, I "flew by the seat of my pants" Many things would change with correct dimensioning.

Heres the detail.