Gobo vs full room treatment

[standup]

I have a practice and recording space in a basement with a ceiling under 7”, so I feel your pain.

From reading about acoustics, I think the reflection of sound between your floor and ceiling will be a big issue.

I have open joists on the ceiling, and I stuffed them all with 4”-8” rock wool. So the entire ceiling absorbs sound. When you walk into that space, you can hear the difference in your voice.

Looks like you have a drywall ceiling, so that’s not an option. But after you get your wall panels in place, consider a “cloud” over the spot where you get the best sound in the room. I have a few products from GIK, I trust them. They’re happy to give you advice. I would suggest 4” panels if possible for the cloud, not foam or thin panels.

[jim1960]

Originally Posted by standup

They’re happy to give you advice. I would suggest 4” panels if possible for the cloud, not foam or thin panels.

If you have adequate low frequency treatment in the corners and at the reflection points, your cloud is really there to deal with the higher frequency stuff. It doesn't hurt to use the 4" thick traps but the 2" traps will get the job done there.

I posted this in another thread. This is a basic layout for a small rectangular room. Dimensions are a little off which makes the second reflection point traps look further back than they'd actually be but the general gist is correct. Doors and windows will force some compromises on placement of some traps but this layout covers the corners where you get low frequency build up, minimizes reflections with the other bass traps, and further minimizes reflections in the recording/mixing area with a 2" cloud.

[zenpicker]

Originally Posted by jim1960

If you have adequate low frequency treatment in the corners and at the reflection points, your cloud is really there to deal with the higher frequency stuff. It doesn't hurt to use the 4" thick traps but the 2" traps will get the job done there.

I posted this in another thread. This is a basic layout for a small rectangular room. Dimensions are a little off which makes the second reflection point traps look further back than they'd actually be but the general gist is correct. Doors and windows will force some compromises on placement of some traps but this layout covers the corners where you get low frequency build up, minimizes reflections with the other bass traps, and further minimizes reflections in the recording/mixing area with a 2" cloud.

Thanks for this! Very helpful. My room is L-shaped so I would need to adapt it, but it helps me visualize what to do. This morning I tried rearranging the room so that my recording position is at right angles to the mixing desk, which gives me a little more flexibility in positioning traps without ruining the room for other non-music uses.

And I will be adding a cloud array. I'm going to put some inconspicuous mounting hooks in the ceiling so that I can take down the cloud when I'm not in a recording phase - an advantage of a low ceiling. The ONE advantage... The more I've noodled on this, the more I think I can design it so I can quickly set up my traps and gobos and cloud, then stow them when not recording. Since I tend to record in pushes of a few weeks at a time this should be a nice way to keep the room multi-use.

[zenpicker]

Originally Posted by standup

I have a practice and recording space in a basement with a ceiling under 7”, so I feel your pain.

From reading about acoustics, I think the reflection of sound between your floor and ceiling will be a big issue.

I have open joists on the ceiling, and I stuffed them all with 4”-8” rock wool. So the entire ceiling absorbs sound. When you walk into that space, you can hear the difference in your voice.

Looks like you have a drywall ceiling, so that’s not an option. But after you get your wall panels in place, consider a “cloud” over the spot where you get the best sound in the room. I have a few products from GIK, I trust them. They’re happy to give you advice. I would suggest 4” panels if possible for the cloud, not foam or thin panels.

Agreed! Probably going to do exactly that.

[standup]

From a room calculator I found, it looks like the modes for a 7’ ceiling are around 80/100/140 hz, definitely in the range of the low end of an acoustic guitar.

I’m no expert, but I would tend toward thicker treatment myself. Thus the. 4” of rock wool in my ceiling joists, and 8” over the desk and monitors as well as over the drum kit.

[zenpicker]

Originally Posted by standup

I’m no expert, but I would tend toward thicker treatment myself. Thus the. 4” of rock wool in my ceiling joists, and 8” over the desk and monitors as well as over the drum kit.

Since I'm going with a removable cloud that I can stow when not recording, maybe I could in fact do something thicker like that. It might feel like the sky is falling while recording, but at least I can take it down when done. Seems like the best compromise overall. I envy you your open joists!

[jim1960]

Originally Posted by zenpicker

I envy you your open joists!

Tear down your ceiling and show some dedication to the craft!!!

[zenpicker]

Originally Posted by jim1960

Tear down your ceiling and show some dedication to the craft!!!

Don't tempt me!

[Steev]

Hi Edward!

I'm late to the party as usual. Plenty of good advice here already.

I would move your chair around and hunt for a sweeter spot out of the middle of the room. Even just angling it so that your soundhole isn't shooting straight at your window might gain some HF dispersion.
Would some heavy curtains help? You could test this just by hanging a few blankets from the curtain rods and have another listen.
The loaded bookcases are great for dispersion, can they be moved around a bit so that they are opposite any blank walls? Or even just angled few degrees.

Those Umiacoustic squares could actually be a bit useful, they are pretty cheap and with a couple of packs o' 12 you could make a lightweight double thickness 4 x 5' ish cloud. If they don't do much then make weird curtains out of them...

Also as Eric queried your mic proximity, remember the good old inverse sq law, is your friend. Every halving of mic distance doubles the guitar volume and halves the sound of the room.

We must do lunch!

[zenpicker]

Originally Posted by Steev

Hi Edward!

I'm late to the party as usual. Plenty of good advice here already.

I would move your chair around and hunt for a sweeter spot out of the middle of the room. Even just angling it so that your soundhole isn't shooting straight at your window might gain some HF dispersion.
Would some heavy curtains help? You could test this just by hanging a few blankets from the curtain rods and have another listen.
The loaded bookcases are great for dispersion, can they be moved around a bit so that they are opposite any blank walls? Or even just angled few degrees.

Those Umiacoustic squares could actually be a bit useful, they are pretty cheap and with a couple of packs o' 12 you could make a lightweight double thickness 4 x 5' ish cloud. If they don't do much then make weird curtains out of them...

Also as Eric queried your mic proximity, remember the good old inverse sq law, is your friend. Every halving of mic distance doubles the guitar volume and halves the sound of the room.

We must do lunch!

Ah, my partner in musical crime...so nice to hear from you, my friend. P says hi. Lunch for sure.

These are all great suggestions. I've actually shifted my playing position 90 degrees now (it's an L-shaped room, as you may recall) and started experimenting with the new gobos (see photo). Some improvement in sound for sure, but not there yet.

Now I am contemplating:

- Beefing up the gobos by backing the 2" pyramidal foam with 2" of solid acoustic foam (e.g. https://www.amazon.com/AKTRADING-CO-...6&sr=8-43&th=1)

- Building a couple more gobos to go behind me - hopefully will address an issue of (other) windows behind me about 8'

- Building a cloud

- Maybe bass-trapping the corners visible over the gobos - necessary if the gobos are 48" tall and I'm sitting? I can't picture bass reflections getting back over the top of the gobos and hitting the mikes' cardioid field, but I could be wrong about that. Admittedly I am hearing some rumble on the bass end but it may be partly that I need fresh strings. Will put them on later and try again, maybe post a rough recording here.

Step by step...with help from the brain trust here. Many thanks!

[jim1960]

Originally Posted by zenpicker

I can't picture bass reflections getting back over the top of the gobos and hitting the mikes' cardioid field, but I could be wrong about that. Admittedly I am hearing some rumble on the bass end but it may be partly that I need fresh strings.

You're using foam which is fairly ineffective in controlling the low end. The frequencies aren't being effectively attenuated in your room at the places where they first build up (the corners) so from there they're bouncing all over the place.

[zenpicker]

Originally Posted by jim1960

You're using foam which is fairly ineffective in controlling the low end. The frequencies aren't being effectively attenuated in your room at the places where they first build up (the corners) so from there they're bouncing all over the place.

Ah, thank you. That makes sense.

[MikeBmusic]

Originally Posted by jim1960

You're using foam which is fairly ineffective in controlling the low end. The frequencies aren't being effectively attenuated in your room at the places where they first build up (the corners) so from there they're bouncing all over the place.

^^^Exactly! You 'hear' the difference, because the foam does absorb some high frequencies, but leaves the mids and lows untouched.

[KevWind]

And just to add to what Mike and Jim have said with the bass frequencies (or any frequencies for that matter) it is not a matter of going over the top of the 48" inch foam panels. It is a matter of going through the panels .
The spec to pay attention to in that that regard, is the NRC coefficient number (which will give an indication of the absorption ability) for which foam is almost always less than materials like OC 703 or Rock Wool