Clark Griswald builds a sound booth...a.k.a. HELP Please!!!

Craig G

New member
After nearly three months of research, experimentation/troubleshooting, and a bunch of expenditure, I have arrived at a brick wall in a quest to get the equipment & environment correct for decent voice over recording. I am hoping the sages here can point me in the right direction before I spend any more time or another dollar in waste.

In short, the problem I am encountering is a general mudiness/harshness in recordings and extensive presence of resonant frequencies regardless of microphone, input/recording device, or experiments with the design and location of my booth.

The booth I am troubleshooting is a 54" x 63" X 73" PVC cage lined with acoustic blankets and carpet over hardwood floor. I also constructed five 4" rockwool panels which are temporarily laid against the corner walls in attempt to absorb nearby wall reflections. I've conducted a bunch of unsuccessful experiments over the past few months including placing the rockwool panels inside the booth, loading up the booth with pillows and extra sound-absorbent stuff, relocating the booth in my garage, taking out all furniture and equipment, mic placement, etc...All to no avail!

Attached are pics of the booth and recording environment.

I originally purchased a Rode NTG-3 shotgun mike in hope of using it flexibly for both voice over and video work. The Rode treats my voice well outdoors, but in the booth the recordings are terrible! By the time I realized an MKH-416 would have been worth an extra $300, B&H would no longer accept a return on the Rode. So I purchased two other mikes to try: Aventone CV-12 & Shure SM7b. The resonant frequencies in the CV-12 recordings (all polar patterns) were full-spectrum, off-the-chart madness! I couldn't even isolate individual frequencies with surgical EQ. Although SM7b fared much better (when set for flat or performance-boost), the recordings are still muddy with pronounced resonance scattered throughout the 100-1400 hz range.

While experimenting with Audition and iZotope RX 8, I discovered that reverb may be playing a role. Running a de-reverb filter seemed to make the recordings more workable and didn't need as much aggression with notched EQ to reduce the resonant freqs. Nevertheless, no amount of surgical EQ, de-reverb, or de-noise seems to be successfully in salvaging them. Or at least that I’ve been able to accomplish.

I realize a PVC blanket booth in a living room isn't exactly an ideal studio set-up. But unfortunately, that's what I'm working with under current conditions. I can deal with poor sound isolation by recording late at night. I just need to get the audio quality under control. The recordings are for some online training videos and a separate personal project. They don't need to be at pro-level of perfection, but at least a level where poor audio quality doesn't distract from the viewer's experience.

I tried attaching links to a few sample files, but as a newbie the homerecording forum isn't allowing hyperlinks or attachments on my posts yet. I did post them on the Gearslutz web site in: Forums -> Studio Building / Acoustics -> "Help needed in resolving acoustic problem in vocal recording booth" by Craig G.

Any advice in remedying the recording situation or suggestions for successful post-production cleanup is VERY, VERY GREATLY appreciated!!!!
 

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Hi Craig. Welcome to the forums.
That's, er, some setup you have there! :D

Can you attach an audio clip demonstrating the issue, and tell us how far away from the microphone you are?
Even in the worst of rooms a 7b a few inches away should be, at least, passable.
 
If thats all you have regards your booth, then that is the story. It could still work for you by limiting any outside noise to recording your voice work late at night when the noise of traffic etc has gone.

Treating the sound in your 'booth' is easier and there should be no reason why those sound blankets havent done something if you were enclosed. So a back and a roof on your booth with more sound blankets. To beef it up you could hang a few duvets up as well.

The microphones I have seen quite a few people use the Rode NT1A for voice work. A kit of that mic is about £150.00 and you will have a good pop filter etc. But I would think about getting a descent interface like an Audient. The pre-amps are very good and quiet. An ID4 will be around £120.00.

Can I see a monitor of laptop there in front of your seat? You may get a little 'bounce' off a monitor, so you could place it in a position where the sound does not bounce onto your mic and is absorbed by your sound blankets. But a Laptop of pc in your booth is a big NoNo, because the noise from them will ruin any recording. Cooling fans etc.

A shotgun mic will pick everything up in front of it for a great distance. So if you arent in a proper booth there could be lots of noises which you will only hear in playback that it has picked up.

I should hope your cooling fan isnt on while you are recording?

Nice little dog.
 
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If thats all you have regards your booth, then that is the story. It could still work for you by limiting any outside noise to recording your voice work late at night when the noise of traffic etc has gone.

Treating the sound in your 'booth' is easier and there should be no reason why those sound blankets havent done something if you were enclosed. So a back and a roof on your booth with more sound blankets. To beef it up you could hang a few duvets up as well.

The microphones I have seen quite a few people use the Rode NT1A for voice work. A kit of that mic is about £150.00 and you will have a good pop filter etc. But I would think about getting a descent interface like an Audient. The pre-amps are very good and quiet. An ID4 will be around £120.00.

Can I see a monitor of laptop there in front of your seat? You may get a little 'bounce' off a monitor, so you could place it in a position where the sound does not bounce onto your mic and is absorbed by your sound blankets. But a Laptop of pc in your booth is a big NoNo, because the noise from them will ruin any recording. Cooling fans etc.

A shotgun mic will pick everything up in front of it for a great distance. So if you arent in a proper booth there could be lots of noises which you will only hear in playback that it has picked up.

I should hope your cooling fan isnt on while you are recording?

Nice little dog.

The blankets are the Producers Choice series from vocalboothtogo (using the same material as the VOMO mobile sound booth). They seem to be functioning well in reducing reverb and absorbing sound. But someone yesterday mentioned that they may be functioning a bit like a low pass filter and allowing more of the low and mid frequencies to pass back into the booth after reflection on the nearby walls. It sort of makes sense as most of the resonance seems to be in that frequency range. I was also told the proximity to the corner walls of the room may be pronouncing this low frequency problem even further.

Regarding the interface, I'm using a Scarlet Solo right now and cloudlifter with the SM7b. It is a bit noisy, but I discovered I can tame the noise to an acceptable level with a few light passes of voice de-noise in iZotope RX 8 followed by a noise gate in Audition. With the Rode NTG-3, I need very little gain from the Scarlet and the recordings are pretty clean.

The monitor in the booth is a 12" LCD for controlling Audition and viewing my levels during recordings. I keep the laptop on the nearby table outside the booth. I originally thought the furniture might be an issue as well and experimented with removing everything except the mic, mic stand, chair, and tablet. Basically recording naked. But the resonance and muddiness issue was still there.
 
I am considering also building an exterior layer of removable sound panels walls from 4" of rockwool and PVC frames. Someone suggested that may help with absorbing the low and mid frequency reflections that may to be re-entering the booth. I would only need another six panels of 2" rockwool and materials to complete that.
 
Hi Craig. Welcome to the forums.
That's, er, some setup you have there! :D

Can you attach an audio clip demonstrating the issue, and tell us how far away from the microphone you are?
Even in the worst of rooms a 7b a few inches away should be, at least, passable.

Thanks for the response. Unfortunately, the forum doesn't allow new users to post links or attachments. I did post samples on the Gearslutz forums in a post titled "Help needed in resolving acoustic problem in vocal recording booth" under the "Studio Building / Acoustics" forum.
 
The blankets are the Producers Choice series from vocalboothtogo (using the same material as the VOMO mobile sound booth). They seem to be functioning well in reducing reverb and absorbing sound. But someone yesterday mentioned that they may be functioning a bit like a low pass filter and allowing more of the low and mid frequencies to pass back into the booth after reflection on the nearby walls. It sort of makes sense as most of the resonance seems to be in that frequency range. I was also told the proximity to the corner walls of the room may be pronouncing this low frequency problem even further.

Regarding the interface, I'm using a Scarlet Solo right now and cloudlifter with the SM7b. It is a bit noisy, but I discovered I can tame the noise to an acceptable level with a few light passes of voice de-noise in iZotope RX 8 followed by a noise gate in Audition. With the Rode NTG-3, I need very little gain from the Scarlet and the recordings are pretty clean.

The monitor in the booth is a 12" LCD for controlling Audition and viewing my levels during recordings. I keep the laptop on the nearby table outside the booth. I originally thought the furniture might be an issue as well and experimented with removing everything except the mic, mic stand, chair, and tablet. Basically recording naked. But the resonance and muddiness issue was still there.

Before you do anything else if it were me I would try another mic and probably interface because you are listing problems which are more complicated than perhaps you should be experiencing.
 
The SM7B clip sounds like it's heavily processed, or the two clips have their names switched up.
It's unnaturally bright with all the mouth noises and lip smacking.

I don't hear the room as a problem in either clip, though.

Get a few posts under your belt and share a completely raw wav, if you wouldn't mind. :)
 
Before you do anything else if it were me I would try another mic and probably interface because you are listing problems which are more complicated than perhaps you should be experiencing.

Orson, thanks for the reply! I've tried three mics now: Aventone CV-12, Shure Sm7b, and the Rode NTG-3. In addition to the Scarlet interface, I've tried using a TASCAM DR-40x recorder directly.

It's possible the mics are accentuating the low freqs (they're both warm mics and my voice is pronounced in the low-mid range), but the problem has been consistent and seems to be environmental.

Or perhaps I just have a muddy voice that produces random harmonic frequencies (joking...but I haven't fully dismissed that possibility. :facepalm:)
 
The SM7B clip sounds like it's heavily processed, or the two clips have their names switched up.
It's unnaturally bright with all the mouth noises and lip smacking.

I don't hear the room as a problem in either clip, though.

Get a few posts under your belt and share a completely raw wav, if you wouldn't mind. :)

Thanks for taking the time to find that URL and listen. Both of those files are unprocessed. I'll post a few more and upload another raw wav.
 
No problem. That's pretty surprising, with the 7b being so much brighter than the other.

and tell us how far away from the microphone you are?
I guess, from the lip smacking, you're very close.
Normally that's what I'd suggest to minimise room noise in a recording but, as I say, I don't hear the room as a problem here.

What I hear is a good voice with buckets of bass, which is maybe what you're not liking?

It's a balancing act - To get those lip smacks and pronounced bass down you'd move back from the microphone a few inches, or a few more.
In doing that, though, your hiss is just going to be louder, relative to the recording, and if the room does suck that's going to become more audible.

Not much use to you but if the 7b clip had no hiss and no mouth noises, I'd call it a great (bassy) VO.

What kind of distance are you at with the shotgun? If very close I'd try moving it back a little and seeing what effect that has on the bass.
 
Orson, thanks for the reply! I've tried three mics now: Aventone CV-12, Shure Sm7b, and the Rode NTG-3. In addition to the Scarlet interface, I've tried using a TASCAM DR-40x recorder directly.

It's possible the mics are accentuating the low freqs (they're both warm mics and my voice is pronounced in the low-mid range), but the problem has been consistent and seems to be environmental.

Or perhaps I just have a muddy voice that produces random harmonic frequencies (joking...but I haven't fully dismissed that possibility. :facepalm:)

Well if your voice is in the mid range how come you have turned into Barry White in your vocal booth. Go sit on the settee and try it there and see if you sound like old Bazzer then.

Unless you have your head in an oil drum I cant see how you suddenly become a low bass voice. Something else going on if that is the case.
 
The SM7B clip sounds like it's heavily processed, or the two clips have their names switched up.
It's unnaturally bright with all the mouth noises and lip smacking.

I don't hear the room as a problem in either clip, though.

Get a few posts under your belt and share a completely raw wav, if you wouldn't mind. :)

I confirmed. Those clips on Gearslutz are correctly attributed to the mics. As for the brightness of the SM7B, I had it set to performance boost position on that recording.

I'm gonna try another experiment tonight and move the booth into the center of the room, angle it oblique to the room walls, and place all sound panels on top to buffer the ceiling. That won't be a sustainable solution, but it will at least tell me if the proximity to the corner of the room is contributing to the resonance in the lows and mids. If that doesn't work, I'm fully out of ideas.
 
Well if your voice is in the mid range how come you have turned into Barry White in your vocal booth. Go sit on the settee and try it there and see if you sound like old Bazzer then.

Unless you have your head in an oil drum I cant see how you suddenly become a low bass voice. Something else going on if that is the case.

I've heard the Barry White comparison before. Michael Douglas is one I hear a lot. Maybe my voice does lean more to the lows. However, it seems much more pronounced in the booth recordings. Tonight I'll do another rounds of test recordings for good comparison...outdoors and in the booth with the booth in different locations of the room.

Its a better way to spend the evening than watching US election coverage!
 
Thank you very much! Yes, number 2 sounds much better. Number one was obviosuly cleaner than my raw file (lip smacks and noise), but still had noteworthy resonant freqs in the mids and distortion in the lows. How did you process the second file?

Just a lot of very small precise eq adjustments.
I said I didn't hear the room as an issue earlier, because I didn't hear an obvious room sound there, but on closer inspection there's a hell of a lot of really live/ringing frequencies.
They just don't ring for long. I picked through and tried to subtly reduce the worst offenders.
More could be done...I suppose if that gets a result you're happy with you could save an eq preset and just keep the setup and environment consistent?

I am wondering if bringing two rockwool panels in really close might work better, though - Like a big open book that you and the microphone are in.
 
Just a lot of very small precise eq adjustments.
I said I didn't hear the room as an issue earlier, because I didn't hear an obvious room sound there, but on closer inspection there's a hell of a lot of really live/ringing frequencies.
They just don't ring for long. I picked through and tried to subtly reduce the worst offenders.
More could be done...I suppose if that gets a result you're happy with you could save an eq preset and just keep the setup and environment consistent?

I am wondering if bringing two rockwool panels in really close might work better, though - Like a big open book that you and the microphone are in.

That's what I was observing too. I've been calling them (perhaps wrongly) resonant frequencies. And they are very random in where and when they appear, requiring that I notch EQ every line individually.
 
You should not be having so many issues regarding your recorded sound. I don't know what material the whole 'booth' is made of, but looks like it could be absorbing all the highs leaving you with a low end, and if your voice is deep, that's not good.
But with 5 real acoustic panels, you should have all you need. Set up 3 in a spread 'U' shape about 18-24" in front of the mic, two behind you a few feet. The height should be so that your mic height is about halfway of the vertical dimension of the traps. If your panels are rockwool or compressed fiberglass, this should be all you need to record a fairly flat tone with little room sound.
 
Thanks to everybody for input and suggestions!

I did two experiments last night. One, as proposed by mjbphotos, bringing the panels inside the booth and enclosing them around myself while the booth remained in the corner. That actually had very little effect. The muddiness and pronounced resonance was still there.

Then I moved the booth into the center of the room at an oblique angle to the surrounding room walls. I also stacked all the sound panels on top to catch any reflections from the nearest wall surface (the ceiling). WOW! What a difference.

View attachment TEST02A-Booth-in-middle-of-room_01.mp3

There’s some resonant frequencies here and there (as indicated in the screenshot below), but they could be easily tamed with -3 to -4 dbs of gain and a tight Q.

We’re finally in business!!!

I wish I could say the same for the Rode NTG-3. The project I am working on requires some talking head/green screen video segments and I was hoping to use the booth for that purpose. After testing last night, that mic is still unusable in the booth. I suppose I’m going to need to rent a studio for those segments or wait a month or so for the crickets to die off and shoot it outdoors. (Hmmm...I wonder if RX 8's spectral noise removal can get rid of crickets. Perhaps an experiment for another night!)

Booth-in-middle-of-room.jpgEQ.jpg
 
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