Best size for recording room? And what acoustic foam to get?

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Best size for recording room? And what acoustic foam to get?

Permanent link to this post Posted by weiss24 » Sat Sep 03, 2016 12:28 am

Hello

I've got two rooms to choose from for setting up the recording equipment. Are these two rooms just about the same, or is one clearly preferable to the other?

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And would acoustic foam such as this be fine (retails at 12.49$ / six panels at eBay), or would it be better to invest in something more expensive?

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Re: Best size for recording room? And what acoustic foam to

Permanent link to this post Posted by kozikowski » Sat Sep 03, 2016 12:53 am

I'm leery about acoustic foam that's a "good deal" and doesn't make you gasp. It's super easy to produce packing foam in about the right shape pass them off as the real thing. Packing foam's job is to take up room and not weight anything. Acoustic foam's job is to be heavy and suck up sound.

Is the cellar classic construction with wooden beams holding up the floor above? Use that and then hang furniture moving pads behind you.

Pix 2 and 3 are a stand-alone sound wall I designed. The design is to build four, put a couple of pads on the floor and press record. I've used it several times.

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You can put double thick pads on the other walls, too. Don't forget the floor and desk. See first pix and below.

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That book and towel thing is a floor vibration isolator. If you have a boom and spider isolation mount...

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...you don't need that, but the pad on the table is still a good idea.

That pix is expensive rubber bands. If you're handy, you can build one from real rubber bands and PVC pipes.

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http://www.kozco.com/tech/pvcShockMount/shockmount.html

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Re: Best size for recording room? And what acoustic foam to

Permanent link to this post Posted by kozikowski » Sat Sep 03, 2016 12:57 am

There was a recent posting from someone who built a min-studio out of pushed-together PVC pipe. Worked well and knocked down when she was done.
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Re: Best size for recording room? And what acoustic foam to

Permanent link to this post Posted by rachalmers » Sat Sep 03, 2016 6:07 am

It's the noise reflection that comes from behind you that is the biggest problem. Make sure that there is a vertical padded screen directly behind the person speaking. Even an old quilt hung over a rack works.
Also, if you can, ensure that there are no parallel wall surfaces, and there is a non-horizontal ceiling. Portable screens can do this.
Then padded acoustic foam is often not necessary.
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Re: Best size for recording room? And what acoustic foam to

Permanent link to this post Posted by kozikowski » Sat Sep 03, 2016 1:21 pm

A studio I once had access to had minimal actual soundproofing (think I remember industrial carpeting) but was intentionally designed with no parallel walls. Even the ceiling was tilted. It worked remarkably well and I sent several good recordings through there.

But it wasn't portable...

One further note the cellar is less likely to pick up neighborhood and traffic noises. Heavy trucks are a problem no matter where you are.

Ian, famous for the longest thread in the forum history lives at the intersection of Venice and La Brea in Hollywood (a metaphor and a real geographic location). He records at night.

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Re: Best size for recording room? And what acoustic foam to

Permanent link to this post Posted by steve » Sat Sep 03, 2016 2:08 pm

kozikowski wrote:A studio I once had access to had minimal actual soundproofing (think I remember industrial carpeting) but was intentionally designed with no parallel walls. Even the ceiling was tilted. It worked remarkably well and I sent several good recordings through there.

Depending on what you are recording, the recording room does not always need to be acoustically "dead" (no reverberation). More important is that it is acoustically "neutral" (no noticeable resonant frequencies). Many great orchestral recordings are made in places that have very substantial amounts of natural reverberation, but a good orchestral space is one that complements the music rather than detracting. In the days before the "reverb effect" was invented, recording rooms were often designed or chosen to provide a reasonable amount of natural reverb, and even today many of the larger studios have a "live room" that is deliberately "not dead".

A room that is totally absent of echoes and reverberation is an anechoic chamber. They environment in such a room feels so unnatural that it would be horrible to try and perform for recording.

For recording spoken word, the recording space usually needs to be fairly dead (substantially free of reverberation and echoes). It is very easy to add (artificial) reverberation if needed, but near impossible to remove excessive reverberation.

"L" shaped rooms can be difficult to work with because the space "around the corner" can act like a resonant chamber, often causing a boominess in bass frequencies.
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Re: Best size for recording room? And what acoustic foam to

Permanent link to this post Posted by kozikowski » Sat Sep 03, 2016 3:31 pm

One of the Producers tried to record in an anecoic chamber and had to add hard panels to avoid the "blackness of space" sound.

One of the things fuzzy pads does is give you freedom to record anywhere without paying attention.

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Re: Best size for recording room? And what acoustic foam to

Permanent link to this post Posted by ericcartman » Sat Sep 03, 2016 8:24 pm

kozikowski wrote:
Heavy trucks are a problem no matter where you are.

Ian, famous for the longest thread in the forum history lives at the intersection of Venice and La Brea in Hollywood (a metaphor and a real geographic location). He records at night.

Koz


would heavy trucks be helped by Steve's LFRolloff filter? I live in the middle of a huge city, and while I have both double-glazing and a "Victorian padded room", I can't get my noise floor under 51-54 and I have always have a spike in my spectrogram at and around 86Hz. If I apply LFRollof filter then compress and Normalise, I can pass ACX Check. But presumably the Compression is regrettable?
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Re: Best size for recording room? And what acoustic foam to

Permanent link to this post Posted by kozikowski » Sun Sep 04, 2016 12:41 am

would heavy trucks be helped by Steve's LFRolloff filter?

You can see it working.
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Steve's Rolloff changes with the "Length" setting. The actual activity is the thin green line, not the heavier blue one. The green line "tightens up" with higher lengths, but the possibility of sound damage goes up.

The filter is designed to suppress both 50Hz and 60Hz, the base power frequencies in Europe and the US, and in effect, elminate everything below them.

85Hs is too close to 100, so no. It won't have any significant affect.

Is it trucks? Does it come and go with traffic? It might be good to go looking for it rather than throwing in the towel and fix it in post.

Is there a straight line hardware path from your microphone to the floor? That's generally not a good thing.

For a long time I had Magic Spot in my studio where the hum and noises went away. It was remarkable. A couple of inches any direction—up, down, sideways—and the hum would come back. One day I climbed into my headphones, fired up my tiny field sound mixer, taped my microphone to a stick and went around the room like that guy at the beach with the metal detector. Found it, too. Turns out my powered music bass cabinet doesn't go off when I switch it off. It stays running spraying low level hum both electrical and sound.

85Hz doesn't sound important other than possibly that's the frequency your house "likes." Rooms and buildings like certain tones. When just the right tone comes by, the room rings like a bell at that tone. It doesn't have to be metal and it doesn't have to be shaped like a bell. Rooms and buildings ring, too.

Los Angeles has done some very serious research on making buildings ring in such a way that earthquakes don't turn them into expensive debris in the street.

Post some of the room noise (Room Tone). 10 second WAV should do it. Scroll down from a forum text window > Upload Attachment > Browse. No filters or effects and don't "help it." Just the noise as you normally experience it.

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Re: Best size for recording room? And what acoustic foam to

Permanent link to this post Posted by ericcartman » Sun Sep 04, 2016 10:07 am

kozikowski wrote:
would heavy trucks be helped by Steve's LFRolloff filter?

You can see it working.
The attachment Screen Shot 2016-09-03 at 17.11.22.png is no longer available


The filter is designed to suppress both 50Hz and 60Hz, the base power frequencies in Europe and the US, and in effect, elminate everything below them.

85Hs is too close to 100, so no. It won't have any significant affect.



that's very interesting, thank you. I assumed it was everything under 100. I seemed to be able to pass ACX Check by applying LFRolloff, but only when I found the thread where you advised someone to turn the length up to the maximum.

kozikowski wrote:

Is it trucks? Does it come and go with traffic? It might be good to go looking for it rather than throwing in the towel and fix it in post.




I myself can hear trucks or buses come and go from time to time, but I can't hear them on the recording, I just hear a general hiss. I have followed your metal detector advice and haven't found a noise source, or a quiet spot with less noise, alas.


kozikowski wrote:

Is there a straight line hardware path from your microphone to the floor? That's generally not a good thing.


it sits on a wooden desk with a glass top. Last night I tried your advice to double up a towel and then put a heavy book on top, but it doesn't reduce the noise floor, at least not visually, according to "start monitoring".

kozikowski wrote:

85Hz doesn't sound important other than possibly that's the frequency your house "likes." Rooms and buildings like certain tones. When just the right tone comes by, the room rings like a bell at that tone. It doesn't have to be metal and it doesn't have to be shaped like a bell. Rooms and buildings ring, too.

Los Angeles has done some very serious research on making buildings ring in such a way that earthquakes don't turn them into expensive debris in the street.


fascinating ! I didn't know.

kozikowski wrote:


Post some of the room noise (Room Tone). 10 second WAV should do it. Scroll down from a forum text window > Upload Attachment > Browse. No filters or effects and don't "help it." Just the noise as you normally experience it.

Koz
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very kind of you, sir.
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