Farmhouse home studio construction

Floor construction pictures! Pics. 1-2 Finnfoam insulation sheets removed and replaced with 50mm Paroc WAS 25T stone wool batts density of 80kg/m3. First 15mm drywall layer on going top of that. Pics. 3-4 Second Layer going down. Seams crossed. Perimeter of drywall layer don't touch the walls. Pics. 5-6 Seams and perimeter of the second drywall layer caulked. Pics. 7-8 Frame lines of acoustic treatment walls. Pics. 9-10 Floor heating mat laid on top of the drywall layer. Pic. 11 All beautiful work covered with small pour (about 5-10mm) of concrete. :D That's all for this time.. -janne

Next job is to make frames of slot resonators over the gybsum walls. First picture shows my original plan. After figuring layout awhile I thought why not cover whole gybsum wall with angled resonator. It ain't eat too much my precious floor space and maybe it's better in acoustically that way... Dark red wall is going to be cloth over rigid insulation. Any thoughts about my new plan :?: I have a question :D Should I fill whole resonators with insulation or only stud cavities against the slats :?: Or maybe rigid insulation say 30-50 kg/m3 against the slats and more loose insulation the rest of the resonator :?: -janne

Or maybe rigid insulation say 30-50 kg/m3 against the slats and more loose insulation the rest of the resonator

Depends on what you are trying to achieve! The insulation in a resonator absorbs energy, but therefore also de-tunes the resonator itself. Technically, it reduces the Q. So as you put more insulation inside it, you make the spectrum coverage broader, but also reduce the absorption for each frequency band. In other words, if you just put a little bit in, the absorption peak will be sharp (small range of frequencies) and high (large absorption). Put lots in and the peak flattens out (covers more frequencies) but also comes down (less absorption per frequency). So it's your call! :) - Stuart -

Thanks again Stuart :D That was exactly THE information I was looking for :D Maybe I'm tuning one resonator and making two more like a broadband. I think there will be quite wild modal activity because the main dimension of the room (W=2,6m L=5,2 H=2,7m) :? -janne

Slot resonator and bass trap frames done! Pics 1-2. Back wall and side wall resonator frames. Pics 3-4. Side wall resonator frame and large corner bass trap frame. Next Flooring installation. -janne

Wood parquet flooring installed :D I manage to get the parquet free of charge from my parents-in-law. That's an old kitchen flooring from their house. :D I carried all the equipment and furnitures from my becoming control room to my liveroom so I can finally start the CR construction. :yahoo:

CR designing and construction :D My original plan was to build room within the room but I decided not to sound isolate the control room. In first picture you can see the main dimensions, window and door positions of the CR. In second picture you can see my construction plan. - All the walls will be covered with 15mm drywall layer, also the window on the right hand side. - I'm moving the storage room door a bit so I can build bass absorber at the corner. - Unfortunately I can't move the entry door position so I've to build movable corner absorber on the other back wall corner. - I'm covering the walls at the perimeter with the 2x3" lumber frame. - Speakers will be soffit mounted. - Left and right side of the listening position will be angled slot resonators. Other walls will be absorbtive (cloth front insulation). Finally the real photos what's the situation now. In first real photo is shown the back wall of the CR. At the left side is the storage room door which will be moved a bit at the right. At the right side is the entry door. Second photo is shown the front wall of the CR. I've to open the ceiling because of cable conduits which leads through the attic to the liveroom. In third photo is shown the cable conduits. Last two photos: I installed 90 degree turns at the conduits and closed the ceiling again. Any thoughts about my plans? :D Thanks! -Janne

I made the first 3d design of my control room with soffit mounted speakers. I've been reading a lot about the soffit mounted speakers and my goal is to do it right :D First sketchup shows the slot resonator positions. They are located at left and right side of the mixing position and straight in front. Second sketchup shows the slot resonators and also the absorbtion positions. Dark red surfaces are cloth front insulation. Last three sketchups show the soffit construction. -Speaker angle is more like 45 degrees than 60 degrees because of the room lenght. At 60 degree angle the listening position is almost the middle of the room :( -It's sealed box, open at the bottom and top. (air flow). -Hangers goes to the bottom part of the soffit box. -Upper part of the box filled with loose insulation. How does my plans look like :?: Am I on the right track :?: Thanks!

generally speaking you want the point of the speaker angle to be between 18 and 24" (450-600mm) behind the listening position to ensure broad coverage over the console, in that space, the 30° should be better. also, the soffits and side walls are going to skew the overall room response so even being close to 50% in that small room, the mode distribution will be different than if the room was simply set up with absorbers etc on the walls.

Thanks Glenn for your input :D Appreciate that! I made quick sketch about the soffits with speaker angle 30° Now the angle point extends about 500mm behind the listening position. How does this look like :?: Thanks!

For maximum effect, the speakers should be in the middle of the soffit panel, not offset to one side. --------- EDITED TO ADD: Since originally writing this a few years back, I have since learned that the speakers should NOT be in the middle of the soffits, but rather offset to one side or the other, in order to avoid creating peaks and nulls in the frequency response. It seems that a position about 2/5 of the width is good. They should also not be centered vertically, for the same reason. That said, you do still need a lot of surface on all sides of the speaker. - Stuart - ---------- - Stuart -

Thanks Stuart! You mean more like that way? I'll draw 3d sketchup pic tonight. speaker angle 30° slats angle 11° -janne

That looks a bit better! Yup! If possible, it is also a good idea to make the soffit panel as wide as possible. This get's a bit complex. Some I already knew, and some I learned from Eric recently: Your soffits will produce a bass boost of 6dB, starting at some frequency that is determined by the width of the soffit. Your speakers should have a control on them somewhere that will roll of the bass by 6dB, and the frequency is determined by a circuit inside the speaker. The question is: does the roll-off frequency of the speaker circuit match the roll-off frequency that your soffit panel will give? So first find out what the roll-off frequency is for your speakers (should be in the manual), then use a simple equation to tell you how wide to make your soffits, based on that frequency. Of course, you don't have to get anal about getting the exact perfect soffit width, down to the last micron, but you should get in the ball-park at least if you can, to avoid having uneven response in the low end. - Stuart -

Thanks Stuart! That's very useful and interesting information. My speakers are now KRKs RP6 and they don't have bass roll off control. Only the HF control. I was thinking to update my speakers to Neumann KH120 A or Adam A7. Don't know yet which. Both speakers do have LF adjustment but Neumann don't inform which is the center of bass roll off frequency.. In Neumann KH120 is +-6db Bass, +-6db low mid and +-6db high frequency adjustments. In Adam A7 manual says that center Frequency of the Bass roll off shelf is at 300Hz. Bass Is adjustable +-6db. http://www.neumann-kh-line.com/neumann- ... ors_KH120A http://www.adam-audio.com/en/pro-audio/ ... escription Now the question :D How do I calculate the right wide of my soffit panel :?: Let's say I'll end up using Adam A7 speakers which have the bass roll off freqency at 300Hz :?: The soffit panels are now 600mm wide. If I make them more wider then slats angle decreases. They're now 11° One option would be to leave slats at 11° and widen the soffit panel closer to the front wall ? (first pic) Then maybe changing the speaker angle to 33° as in second picture. Thanks! -Janne

I was thinking to update my speakers to Neumann KH120 A or Adam A7.

I´ve never used the Neumanns, but I happen to own a pair of A7's, so that would be my choice! But then again, I'm biased... :) How to calculate soffit width? I'm quoting Eric from this post viewtopic.php?f=12&t=718&start=15 "The formula to determine where the compensation takes place is: f3 = 4650/W where x is the baffle width in inches." 300 Hz gives you 15 inches. BUT! This is actually working backwards form the way you first think about it. That control is more accurately an "un-compensation" control. I'm still trying to get my head around this part of it, but the way I understand it is this: Drivers are designed to work with infinite baffles (in other words, a speaker box shows front panel is significantly larger than the wavelength of the very lowest frequency that the speaker can produce). So, if you put that driver in a box that does NOT have an infinite baffle, then you have to compensate for that. So there is a circuit inside that does that: it compensates for the box not being infinitely large.. Now, if you DO mount that box in a soffit, you are approximating an infinite baffle again. So now you need to "un-compensate" for some of that "compensation" that was built in to the speaker when it was designed. That's soft of what the roll-off control does. It assumes that you will be mounting it in a baffle at least 15 inches wide, so it starts rolling off the compensation at 300 Hz. If you use a bigger baffle, that's not a problem, since you will be rolling off all of the compensation anyway, getting back to the ideal "infinite baffle" situation. But you cannot use a baffle of less than 15" wide, since there is no way the speaker can "un-compensate" for frequencies that were not already compensated, if that makes any sense at all! In other words, the absolute minimum width for your soffit is 15", since that's the highest frequency that the speaker can compensate for, but double that width would be even better, as it will extend the response even lower. Personally, for an A7 I'd use something like 30" width, at least.

The soffit panels are now 600mm wide.

According to that equation, with 600mm the baffle step frequency moves down to about 190 Hz, so that's where the new roll-off starts happening. Theoretically, if you made them 6 meters wide, the step would shift down to 19 Hz, so that would be fine! :) Seriously, the A7's response starts rolling off anyway below about 70 Hz, so there isn't any need to go beyond about 1.5m wide ! :shock: But once again, this is all about trade-offs, since at that frequency the speakers are interacting with the walls, floor and ceiling already (the ceiling and floor, at least, will be closer than 1.5 m), so a soffit of 100cm or 120cm is probably more than enough, if you can get it that big. If not, then just go as big as practical. Hopefully that's not too confusing for you, ´cause it sure is confusing for me! (I think I got it straight... Hopefully someone will correct me if I'm wrong...) - Stuart -

Soundman2020 wrote:

I'm quoting Eric from this post viewtopic.php?f=12&t=718&start=15

You are quoting Eric "in" this post, not from this post...Eric wasn't even a part of that thread. What would have helped me as a viewer is if you would have included the actual thread that Mr. Desart was making mention of this notion. Oh well :)

Actually he was quoting me.

I would think that the walls in that configuration would act as a horn and support the bass frequencies. I don't know if it would increase the bass frequencies though, but I'm pretty sure it wouldn't act the same as a free standing speaker.

Eric wasn't even a part of that thread.

Ummm... Yes he was! :shock: You might want to read it again... He posts several times on that thread, with some very useful info.

You are quoting Eric "in" this post, not from this post.

No, I am quoting Eric "from" that post: my English grammar is perfectly correct there, thanks very much.

have included the actual thread that Mr. Desart was making mention of

Who said anything at all about Mr. Desart??? You seem to be a bit confused tonight, Brien! :roll: Although I highly admire Eric Desart, he isn't the only "Eric" on this planet... - Stuart -

... let us not forget Eric the half a bee! :lol: ... "Are all your pets named Eric?" "There's nothing so unusual about that!" ... "Take it away Eric the Orchestra Leader!"

Thanks for the answers guys! :D Damn I love this forum :mrgreen:

Soundman2020 wrote:

I´ve never used the Neumanns, but I happen to own a pair of A7's, so that would be my choice! But then again, I'm biased... :)

I might be able to listen pair of A7's this weekend. I'll hope that they sounds good, so I can make the decision soon which speakers I'm going to use in my studio.

Soundman2020 wrote:

How to calculate soffit width? I'm quoting Eric from this post viewtopic.php?f=12&t=718&start=15 "The formula to determine where the compensation takes place is: f3 = 4650/W where x is the baffle width in inches." 300 Hz gives you 15 inches. BUT!

Yeah! That part of your interesting post makes perfectly sense to me :D And the rest of the post... I'm quite understanding it but I'll have to chew it for awhile. You explained it very clear. Thanks for the link btw.! If I read your post between the lines it's recommendable to use soffit as wide as possible. And as my control room and as many others in this forum we've to make compromises. It's almost impossible to fit 1,2m soffit in my tiny little room... I was thinking to use 800mm (31") soffit panel as you recomended minimum. I made quick sketch of that. Slots are 10° and the speakers are 27° Of course everything depends if I'll end up to use A7's :D

Soundman2020 wrote:

Hopefully that's not too confusing for you, ´cause it sure is confusing for me! (I think I got it straight... Hopefully someone will correct me if I'm wrong...)

Thanks again for the clear explanation! I think I'm little wiser after this day :D

Eric Best wrote:

I would think that the walls in that configuration would act as a horn and support the bass frequencies. I don't know if it would increase the bass frequencies though, but I'm pretty sure it wouldn't act the same as a free standing speaker.

Thanks for your answer Eric but I didn't quite get your point?? Thanks! -janne

I was thinking to use 800mm (31") soffit panel as you recomended minimum. I made quick sketch of that. Slots are 10° and the speakers are 27°

Looks good to me Janne! :) I reckon you should be fine with that, overall, although the 27° angle is a bit low, and might have an effect on your stereo image. The normal recommendation is to not go less than 30° or more than 45°. Maybe you could reduce the panel width just a little, move the speakers just a bit further apart (sacrifice a bit of the slot wall), move the mix position just a bit closer to the front, or something along those lines? - Stuart -

Thanks for your answer Eric but I didn't quite get your point??

It was more of a thought than a point. You are going for a 31" width of wall that you are mounting on. I was think whether this would be necessary. The baffle diffraction loss occurs when the baffle isn't large enough to contain the wave from the speaker and ends up on the side or behind the enclosure. If the walls of the room contain the wave and support it instead of folding behind like they do in a speaker, does it matter how wide the wall is? You won't get the baffle step loss like you would for a speaker that width. I'm just wondering if since the room folds forward of the baffle will this have a positive effect on the bass (as in more , not necessarily better) like the function of a horn? Thoughts?

You won't get the baffle step loss like you would for a speaker that width.

Exactly! That's kind of what I tried to say above. And that's part of the issue: since the speaker manufacturer designed the speaker for it's own very narrow baffle, they have already compensated for that baffle step in the design. The fact of now effectively giving the speaker an infinite baffle means that the "compensation" needs to be "uncompensated" again, since the baffle step is gone. But the question is: how much to uncompensate, and at what point? Theoretically it should be 6 dB, of course, starting at the frequency of whatever compensation was designed into the speaker, presumably related to the width of the actual speaker baffle. But the walls and floor of an average would have had some effect anyway, and I imagine that the designers took that into account as well, so it is unlikely to be a full 6 dB. For the A7s, Adam gives you a rear-panel control that rolls off below 300 Hz anywhere from 0 dB up to 6 dB, which is great. But 300 Hz does not match the speaker cabinet width! According to your formula, 300 Hz would be the right compensation for a 15" baffle, but the A7 front panel is only about 8" (guessing: don't have the exact specs on hand right now). So that kind of confuses things: by using that control, you'll be "uncompensating" starting at the wrong frequency, and by an unknown amount... but I doubt the effect is going to be very large? From the links you provided, it seems like the "bump" in response would be around 2 to 3 dB, correct? The other issue with the soffit (baffle) width is exactly what you said: that plus the walls, ceiling and floor will act as a horn, supporting the low end better, but I'm figuring that the loading would not be correct if the baffle (which forms the "base" of the horn) is too narrow: Won't you be getting strange interference patterns, comb filtering, and lost power due to impedance mismatch if the baffle is really narrow as compared to the lowest wavelength that the speaker can produce? What happens as the edge of a wavefront spreads across the baffle and reaches the wall/floor/ceiling? There has to be some kind of reflection/refraction/diffraction going on at those boundaries, which common sense says you want to happen as far away from the speaker cone as possible. Or am I wrong on that? Speakers are confusing things... :!: - Stuart -

Soundman2020 wrote:

Speakers are confusing things... :!: - Stuart -

You bet! Actually I think I have the speaker thing down, now it is the interacting with the room thing!!!!!!!!!!!!!