Is my vocal booth dead enough? REW graphs

[Jens Eklund]

Originally Posted by glenn_jr

I'm not sure which graphs would be useful, so I've included them all. I apologize if they're not set up right.

Focusing on control rooms but still:

Before posting your measurement results




Your room looks very dead … good if very small vocal booth. Hard to read the ETC with your current scales.

[DanDan]

The Measurements look strange particularly the Waterfall.
Unless you want to learn how to measure, a picture or further verbal description would be useful.

How many walls are covered with fibre?
Is there an air gap behind?
What are the walls made of? Sheetrock, e.g. wood panelling, Concrete?
Is there carpet or is it a hard floor?
If you need additional treatment it would be best to analyse and target.
You could try a simple test. Place your speaker in a floor corner.
Use Frequency follows cursor in the REW signal Generator.
Sweep carefully around 95 and 190 Hz listening for strong resonance.
If you find it, listen throughout the room, all corners in particular.
If those booms are strong you might want to include corner traps.

Irrespective of all the above, if you don't have a large deep Cloud, do install one. The ceiling is the nearest surface to a standing singer.

DD

[Glenn Kuras]

It sounds like to me you are on the right track by covering all the walls with 4" mineral wool or rigid fiberglass. But just to point out.

*6 x 6 feet (got a good deal...couldn't pass it up)
*nearly 7 foot ceiling
*one window

You are square now (well not YOU BUT THE ROOM ) and getting close to a cube so keep in mind that trying to fight that boxy sound is going to be a pretty hard. I would consider cutting main vocals in a open treated room.

[glenn_jr]

Hi everyone. Just woke up and saw the replies. Thank you for your comments.

Let me get some more details for you after breakfast.

First though, I wanted to say again that this is for voice over only. No singing. Occasionally some high energy "hard sell" loudness, but mostly calm reads.

Also, most people who record here prefer to sit.

Thanks!

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[jwl]

Yeah, that room is tough. Something is funky on your low end, I'd suspect somethign went wrong with measurements. Your graphs depict utter chaos below about 60Hz.

There's not much more you can do besides line all walls and ceilings with at least 4" of rockwool or rigid fiberglass. Some even thicker bass traps in the corners will help if you can find the space for them.

For more detail on our small vocal booth strategy, see: RealTraps - Vocal Booths

[glenn_jr]

Hey guys,
I'm guessing the low end problem might be due to the speaker not being up to the task? It's a krk rp5. Possibly struggling to hit those lows? And used only one speaker.

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[glenn_jr]

Ok, time to answer some questions.

To DanDan's questions:

How many walls are covered with fibre?

One full wall is covered with 4" of mineral wool, 48kg/m3. This is the wall that the speaker would be facing. The rest is almost entirely covered with 2" foam.

Is there an air gap behind?

There is no air gap between the wall and mineral wool.

What are the walls made of? Sheetrock, e.g. wood panelling, Concrete?

This is a pre-fab from vocalbooth.com The outer walls are 3/4" OSB. Inside it is covered with maybe 1/2" or 3/4" of what people would call 'soundboard'. (basically looks like mulched up cardboard pressed together. It's very easy to dig into it with your fingers.)

Is there carpet or is it a hard floor?

There is carpet. Albeit, that really tight-knit kind made for busy traffic areas. I wouldn't imagine it's doing much for any type of absorption.

[glenn_jr]

On to how the booth looks...

I'll work on a picture in a bit. For now, here's the written description of the inside:

Four walls, let's call them A, B, C, D

Wall A: One large door. Everything covered with foam (opposite wall D)

Wall B: Has a window, roughly 3x3 feet. Rest of wall covered with foam (opposite wall C)

Wall C: Completely covered with foam, except for 4 vents (opposite wall B)

Wall D: Completely covered with 4" of mineral wool. Thin, breathable fabric over it. (opposite wall A)

I also have a rectangular bass trap I built filled with fiberglass (48kg/m3), measuring 55" long, 14" deep, 14" tall. It currently sits on the floor right up against Wall D, laying length-wise.

I built this because there is a table roughly in the middle of the booth. Between the table and Wall D there is a large gap doing nothing. So I thought I could get some extra bass trapping in there by putting it there. I could in theory sit it upright in one of the corners if it might function better there.

I hope that all makes sense.

[glenn_jr]

Testing Method

I totally could have tested incorrectly; so I thought I would briefly explain how I did it.

It seemed to me logical to set things up as if someone were in their recording, since we would be interested in seeing what types of things are entering the mic at that specific position.

So I placed the speaker at the exact position where someone's head would be when sitting down to record. (facing Wall D).

The microphone was placed in the position where the mic would normally be when someone records: Directly opposite the speaker. Distance was per the "one hand pinky/thumb" distance a voice over talent would often use. (mic facing Wall A)

The mic used was a Dayton Audio EMM-6 with calibration data provided by Cross-Spectrum Labs.

To me that setup seemed the most logical approach. Since the person recording is not moving around and 95% of the time always in that one location, measuring anywhere else in the booth didn't appear to be needed. But I'm of course just guessing here.

Oh! And I should add that for this particular test, I crouched down behind the speaker inside the booth to add more of an accurate representation of what would be in the booth when really recording (a human!). The first time I measured, I wasn't in the booth. With me in there, there wasn't much of a difference except in the low end. It actually seemed to make the low end worse.

[glenn_jr]

Originally Posted by DanDan

You could try a simple test. Place your speaker in a floor corner.
Use Frequency follows cursor in the REW signal Generator.
Sweep carefully around 95 and 190 Hz listening for strong resonance.
DD

I'll give this a try. The booth is located in another room from the control room, so it might take some time. Thanks.

[DanDan]

The first waterfall has a very strange addition at LF.
There is something wrong in the process. Not a placement nuance. A wrong routing choice or setting in a driver app. NG.

From the description, there is no cloud.
Adding one will definitely prevent flutter between ceiling,table, floor. A 4 + 4 or HF MiniTraps/thick GIKs, would have a go a the vertical modes also.

DD

[glenn_jr]

Think I will try the measurement again. Will look more closely at the software settings to see what went wrong.

And regarding the cloud. It currently has the foam on the ceiling, but it's glued directly on. If I make a proper cloud, will there need to be an air gap? Think I could only spare about an inch at most for gap, and 2 inches for the cloud itself.

Thanks

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[DanDan]

If the foam is a reputable type, e.g. Auralex, I would leave it there and add fibre beneath, as thick as you can manage.
DD

[cborg]

I couldn't really tell by the graphs only but I'm guessing it will be alright for regular speech. Looks like some kind of cutoff at 100 (or 85Hz perhaps)?
Have you tried recording something and listened to it? Demo perhaps?
I've got friends making a living on recording instructional videos (among other things) and they're using both custom built booths and commercial with foam. Works very well for them.
In my view the cons are: dry, a bit cramped and bad ventilation. I wouldn't like recording song vocals in there.
The pros: some isolation, privacy, customers often expect a booth (for some reason)

[glenn_jr]

Originally Posted by cborg

I couldn't really tell by the graphs only but I'm guessing it will be alright for regular speech. Looks like some kind of cutoff at 100 (or 85Hz perhaps)?
Have you tried recording something and listened to it? Demo perhaps?
I've got friends making a living on recording instructional videos (among other things) and they're using both custom built booths and commercial with foam. Works very well for them.
In my view the cons are: dry, a bit cramped and bad ventilation. I wouldn't like recording song vocals in there.
The pros: some isolation, privacy, customers often expect a booth (for some reason)

Yeah, you're right on the ventilation. I scrapped the system in place and have a couple of S&P TD SILENT in line duct fans moving air in and out from another room. (I highly recommend these fans) The intake is sucking directly off a large AC in that room and brings plenty of cool, fresh air. Before I made that system...

But for voice over, we've been really happy with it. It's mainly used for recording our Chinese cases. Most of our talents' voices are in the upper registers; it seems to work well for them. It's my lower voice that made me want to treat it some more.

And yes, it offers some isolation but not nearly enough. I had to build a wall near the windows of the room to block outside noise (which worked very well. Thanks to John Brandt for the help with everything) and then treat the walls in the room outside the booth to block other noises. I'll say it's pretty damn silent in that room, ALMOST don't even need the booth.

And so true, we get a lot of customers who specifically ask if we have a booth. I guess voice over and booth are some kind of requirement - kind of like asking if we have a U87.