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4 days to decide: Cut off the rooms corner?

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4 days to decide: Cut off the rooms corner?

Postby Zanvibe » Fri Jul 24, 2020 5:56 pm

I am in the middle of house construction. I have a music room that's about 13'6" by 15'6". 9' ceilings. Right now, all parallel walls, rectangular room. I plan to play, teach, record, and mix in the room. Mostly I record 1 or 2 channels of acoustic instruments and/or voice at a time.
My question: Insulation is about to finish and I have the option before sheetrock starts tuesday to throw up a piece of plywood at cut off one of the rooms corners. I have until Monday to decide and implement. It would be an 18" to 24" long piece of plywood that would span the corner at 30 or 45 degrees.
Is this worth it? Would it make a significant impact in the room's sound to be worth making the room less functional for other purposes (like shelves, art, or furniture)?
In my current small space I have some foam bass traps. I could also bring those into the new space instead of this cut-off corner idea.
Thanks for taking the time to offer your opinions.
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Re: 4 days to decide: Cut off the rooms corner?

Postby Hugh Robjohns » Fri Jul 24, 2020 7:10 pm

Zanvibe wrote:I have the option to throw up a piece of plywood at cut off one of the rooms corners. ... Is this worth it? Would it make a significant impact in the room's sound...

No and no... it would make the room less practical for most purposes, and it may well also mess up the stereo image from your montioring...

In my current small space I have some foam bass traps. I could also bring those into the new space instead of this cut-off corner idea.

Corner bass traps would be an excellent idea... but they need to be proper bass traps to be any use, not the foam things called bass traps which really aren't!
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Re: 4 days to decide: Cut off the rooms corner?

Postby blinddrew » Fri Jul 24, 2020 10:45 pm

If you can afford to lose that space, then lose it to some rockwool bass trapping - that would be my suggestion.
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Re: 4 days to decide: Cut off the rooms corner?

Postby DanDan » Sat Jul 25, 2020 4:44 pm

If your ply were mounted in a way allowing it to vibrate, and if you fill the void behind it, well, that is a membrane faced bass trap. It would be much safer to build large Studiotips SuperChunk triangular traps, or better still big square or rectangular ones, similar to GIK SoffiTraps. Big in all cases though, the wider SSC and 60cm SoffiTraps.

Recently I designed treatment for a venue refurb. The existing plan involved huge areas of plasterboard facing each other and parallel. With little extra trouble or expense we ended up with slightly splayed walls. Hardy visible in the large space but no flutter echo and no loss of HF energy in the room.
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Re: 4 days to decide: Cut off the rooms corner?

Postby The Red Bladder » Sat Jul 25, 2020 6:27 pm

https://www.amazon.co.uk/Home-Recording ... 143545717X

Read that - it'll save you money and give you a better room.

Build your own bass traps - there better than those daft foam things regardless of what they cost. Put them in all corners - ceiling and room corners. Test the room first with a sound meter and a sig-gen https://www.szynalski.com/tone-generator/

I wrote the method down elsewhere -
The Red Bladder wrote:1. Put a mic in the listening position on a stand at head height. (Better still, a calibrated sound meter, but because all we are doing is measuring differences, a mic will do!) Feed the mic to a decent level meter that gives you a fairly accurate reading.

2. Put a single sub in one corner of the room and hook it up with your computer or a tablet/laptop/whatever.

3. Go to this site https://www.szynalski.com/tone-generator/ and pick a low note, say about 40Hz. You will end up trying different notes and tones and finding out quite a bit about your room and learn a bit about acoustics at the same time!

4. Move the sub to different positions around the room until the mic gets the loudest signal. This will probably be about one meter away from the L or R front corner on the floor and against the wall - but need not be. It could be anywhere!

5. Leave the sub there and move the mic around the room. You are going to get null points all over the place; points where there is no bass at all!

6. Repeat steps 3, 4 & 5 with different frequencies until you get a good idea of how the room is behaving. You will now have a mental map of your room and begin to 'feel' how the sound reflects back into the room, creating null-points where the waves cancel one another out.

7. Now put the sub in the best position again and find those spots in the corners of the room where there is waaay too much bass - almost certainly in the ceiling-to-walls corners and the four corners of the room. That's where you are going to put bass traps to swallow the bass and prevent it from returning to cancel out the bass elsewhere.

P.S. Lidl has £10 sound meters tomorrow if you are in the UK. They'll probably be gone fairly quickly as they have not apparently ordered that many.
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