New studio panel advice needed please.

[Mira Music]

Oh dear!

I ordered it hard backed as that's what Stuart recommended.

What's your thinking on this Eric?

[Soundman2020]

Dont make it hard backed.

Why not? He has vertical modal issues, and also flutter echo issues. Hard backed and hung at an angle wont solve those entirely, obviously, but it sure will help. Is there a reason why you think it would be a bad idea to make it hard backed in this case?


- Stuart -

[Soundman2020]

The cloud will be 6' x 6', 4" deep. It will hang at a 12º angle over the mix position.

That's pretty big! You'll need some heavy duty hardware to hang that safely. Think: eye-bolts, chains, ...


- Stuart -

[Mira Music]

The cloud will be 6' x 6', 4" deep. It will hang at a 12º angle over the mix position.

That's pretty big! You'll need some heavy duty hardware to hang that safely. Think: eye-bolts, chains, ...


- Stuart -

It will be 2 separate 6 x 3 panels. Not sure how I'll connect them together yet but yes I was thinking eye bolts and chains. My contractor said he will come by on Sat and help me hang them. I need to find a way to anchor them to the ceiling without undermining the isolation. Not sure about that yet but plan to scour the forums and see what turns up.
I also got the rest of the 4" thick bass traps for the corners and 2 4" panels for the back of the room which will be on stands so I can keep them 4" away from the back wall as you suggested. I can also use them as baffles when I'm recording then move them back for mixing. Then I'll hang the remaining 2 2" panels on the door and on the other side of the piano. That just leaves the ceiling area behind the lights that won't have any absorption. Is diffusion a good idea there?

-A

[RJHollins]

Just a suggestion ...

The 3 hardbacked clouds for my build can be seen here
http://www.johnlsayers.com/phpBB2/viewt ... &start=390

Go about halfway down the page for details & pics.

The clouds are very secure

Under Glenn's guidance, I can also confirm that the floor to ceiling issue is handled with
hardback clouds at an angle. I still have adjustments to make to fine tune & maximize the
treatment.

hope this helps.

[Eric Best]

I just look at the open back as more opportunity for absorption, and the hard back as an extra complication. When 703 is measured off the wall the absorption levels are higher, I just always thought it was because of the extra surface area. It would have to be pretty thick backing and solidly mounted to change the modal issues at 63hz, and the flutter echo at the higher frequencies would be easily absorbed by the fiberglass.

I didn't think it would be a bad thing to be backed, just unnecessary.

I'm not adamant about this, tell me what I am missing.

[Soundman2020]

It would have to be pretty thick backing and solidly mounted to change the modal issues at 63hz,

Exactly right! That's what I'm suggesting: Thick plywood or MDF (perhaps 18mm or so) properly hung on chains, like Brian did (based on Glenn's design). It won't completely change the mode, of course, but it certainly will have some effect. A quarter wavelength at 63 Hz is about 4 1/2 feet, so a hard backed cloud 6 feet on each side is certainly big enough to be noticed by the standing wave. Without the backing, there wont be much effect at all on the mode.

When 703 is measured off the wall the absorption levels are higher,

True, but 4" of absorption isn't very effective down at 60 Hz, even if spaced off the ceiling. For maximum efficiency, it would have to be spaced 53 inches off the ceiling... (theoretically). So spacing it 4" away, or even 6" away, or even 16" away from the ceiling (which is what OC shows in there specs), is not much different than no spacing at all for such low frequencies. It's only a small fraction of what the distance you'd need to have any real benefit.

The angling helps there too (slightly). Angling the cloud at 30°, for example, increases the path length by 50%, so the 4" is effectively 6". Even with only a 15° tilt you are still getting better than 25% increase in path length, so 5" acts like 6".

I just look at the open back as more opportunity for absorption,

Sure! But you can also put absorption on TOP of the hard back, for even more effect! We did that once a few years back in a church here in Chile, and it worked out great. It can't be seen from below anyway, so you don't even need to make it look pretty with cloth over it. We just cut it a bit smaller than the size of the panel, so the edges aren't directly visible from below, and it looks fine.

I didn't think it would be a bad thing to be backed, just unnecessary.

It would be interesting to see tests for backed and unbacked! But I'm betting that there will be a significant effect, like there was in Brian's case. I understand that Glenn does this a lot, and has also had excellent results with it.

Of course, like you say, the backing does have to be substantial: thick, rigid, and massive. And it also has to be well mounted to the ceiling.



- Stuart -

[Eric Best]

Makes sense.

I would think of taking care of the modal problem with tuned helmholtz or panel absorber, but there are so many ways to deal with these things.

[Mira Music]

Just a suggestion ...

The 3 hardbacked clouds for my build can be seen here
http://www.johnlsayers.com/phpBB2/viewt ... &start=390

Go about halfway down the page for details & pics.

The clouds are very secure

Under Glenn's guidance, I can also confirm that the floor to ceiling issue is handled with
hardback clouds at an angle. I still have adjustments to make to fine tune & maximize the
treatment.

hope this helps.

Thanks so much RJ! Yes it helps enormously! I was wondering how i was going to mount the cloud. I have access to the space behind my ceiling so I'll climb up there first and do precise measurements of the ceiling joists. I then plan to get some large eye hooks and screw them through the 2 layers of 5/8 and into the joists. Then chain and S hooks for the cloud. I'm going to pick up the cloud in a few hours so I'll have a better idea of what it weighs before I shoot down to Home Despot and pick up the hardware.

How is your mini-split working out? I have had huge issues with my installation but it looks like they finally got it right yesterday. I'll be adding a long explanation to my construction build thread soon so hopefully others can avoid the mistakes we made.

Thanks again for your input!

-A

[Mira Music]

It would have to be pretty thick backing and solidly mounted to change the modal issues at 63hz,

Exactly right! That's what I'm suggesting: Thick plywood or MDF (perhaps 18mm or so) properly hung on chains, like Brian did (based on Glenn's design). It won't completely change the mode, of course, but it certainly will have some effect. A quarter wavelength at 63 Hz is about 4 1/2 feet, so a hard backed cloud 6 feet on each side is certainly big enough to be noticed by the standing wave. Without the backing, there wont be much effect at all on the mode.

When 703 is measured off the wall the absorption levels are higher,

True, but 4" of absorption isn't very effective down at 60 Hz, even if spaced off the ceiling. For maximum efficiency, it would have to be spaced 53 inches off the ceiling... (theoretically). So spacing it 4" away, or even 6" away, or even 16" away from the ceiling (which is what OC shows in there specs), is not much different than no spacing at all for such low frequencies. It's only a small fraction of what the distance you'd need to have any real benefit.

The angling helps there too (slightly). Angling the cloud at 30°, for example, increases the path length by 50%, so the 4" is effectively 6". Even with only a 15° tilt you are still getting better than 25% increase in path length, so 5" acts like 6".

I just look at the open back as more opportunity for absorption,

Sure! But you can also put absorption on TOP of the hard back, for even more effect! We did that once a few years back in a church here in Chile, and it worked out great. It can't be seen from below anyway, so you don't even need to make it look pretty with cloth over it. We just cut it a bit smaller than the size of the panel, so the edges aren't directly visible from below, and it looks fine.

I didn't think it would be a bad thing to be backed, just unnecessary.

It would be interesting to see tests for backed and unbacked! But I'm betting that there will be a significant effect, like there was in Brian's case. I understand that Glenn does this a lot, and has also had excellent results with it.

Of course, like you say, the backing does have to be substantial: thick, rigid, and massive. And it also has to be well mounted to the ceiling.



- Stuart -

Thanks for all this input guys!

I wasn't sure what to do so I ordered the cloud without backing. I can always add the backing later if I make sure that the ceiling anchors can take the extra weight. I plan to over compensate for that even though I will be hanging the cloud without backing for now.

Stuart, I tried a rough version of your idea for my back wall by taking 2 of my 2" deep panels and putting them on stands about 4" away from the back wall. It really did make a difference! I will be picking up the 4" deep panels today as well so I'll let you know how it turns out.

I will also do some REW testing before and after the cloud and rear panels and will post my findings. I plan to test only from the mix position and will do 5 or 6 tests then average them out. Does this sound right?

-A

[Mira Music]

Makes sense.

I would think of taking care of the modal problem with tuned helmholtz or panel absorber, but there are so many ways to deal with these things.

Yes I would agree Eric. That's my "last resort" plan as I have mentioned before that my construction skills are less than zero. I'll do it if it's the only way to deal with the modal problem. I can't see myself spending so much on my room and my monitors and then flaking on the last thing to make the room sound right!

Of course I might have to wait till some $$ comes in though!

-A

[Soundman2020]

I wasn't sure what to do so I ordered the cloud without backing. I can always add the backing later

Cool! So maybe we CAN do those tests, and settle the issue (to a certain extent). take careful REW measurements just before you put the cloud up, then again when it is up, then take it down, put the backing on, put it back up again, and take the final measurement.

if I make sure that the ceiling anchors can take the extra weight.

Shouldn't be a problem: each 6' x 3' panel of 3/4" plywood will weight about 40 pounds (3/4" is roughly 2.2 lbs/ft2). Let's be generous and add another 40 pounds for the frame, rock wool and mounting hardware (VERY generous), that means each cloud will weigh about 80 pounds. Spread that across 6 chains / eye bolts (three down each side of the panel), and each chain / eye bolt is holding only about 13 pounds. So it shouldn't be a problem, assuming that your joists can handle an extra 160 pounds total load. Once again, that will be spread across 3 joists, so each joist only needs to handle an extra 55 pounds, roughly.

(Somebody check my math, please! Did that in a hurry... gotta run...)


- Stuart -

[Mira Music]

Cool! So maybe we CAN do those tests, and settle the issue (to a certain extent). take careful REW measurements just before you put the cloud up, then again when it is up, then take it down, put the backing on, put it back up again, and take the final measurement.

Yes! Did my plan of taking 5 or 6 measurements around the mix position and then averaging seem like the right thing to do?

Shouldn't be a problem: each 6' x 3' panel of 3/4" plywood will weight about 40 pounds (3/4" is roughly 2.2 lbs/ft2). Let's be generous and add another 40 pounds for the frame, rock wool and mounting hardware (VERY generous), that means each cloud will weigh about 80 pounds. Spread that across 6 chains / eye bolts (three down each side of the panel), and each chain / eye bolt is holding only about 13 pounds. So it shouldn't be a problem, assuming that your joists can handle an extra 160 pounds total load. Once again, that will be spread across 3 joists, so each joist only needs to handle an extra 55 pounds, roughly.

OK so here is where I am at with that. My ceiling joists appear to be 2 x 7.3" after measuring them. I was at the hardware store and the guy said I should try and go THROUGH the entire joist with an eye bolt and then use a washer and nut on the back followed by some thread glue. This is the bolt he suggested. It's 1/2"x12".

IMG_2933.jpg

My idea was to use something like this....

IMG_2932.jpg

so it screws into the joist quite a ways. I think with 3 down each side of the panel it should be good. Am I wrong?

Here is the space in the ceiling...

IMG_2937.jpg

[Eric Best]

I would think that those are overkill.

[Mira Music]

I would think that those are overkill.

Ha!

Short and to the point!

Thanks Eric, that's what I thought too. I will go with the screw in eye bolts.

-A