Semi Portable vocal booth construction
Advice most welcome please.
I have read posts on vocal booth construction, very good advice and a link to http://www.gikacoustics.com/
This may be the way to go, with their mobile booth and add a false ceiling. I need a second vocal booth, something mainly free standing, for a new location that is not mine, so I cannot make major modification to walls and ceilings.
The space available, without windows is 8 ft high and 5 ft square (250 cm high and 150 cm square) - it is like a 6 person lift with a high ceiling.
Whereas there is no external noise to cancel out, I want to tune the space and reduce echo off the plain plaster walls for 1 mic voice overs. I can of course use studio foam panels but what is the best solution to support them, a framework or solid wood sheets onto which studio foam panels are glued?
If I use standard sheets of wood that are heavy they will need substantial holes in the side walls to support them and the false ceiling. I can drill some holes in side walls and place some supporting battens.
I prefer a lightweight solution to hold the foam panels in place on the walls and ceiling that I can dismantle. If this was a thin plywood do you think this would give a similar effect as if the wood behind the foam was heavy, thicker sheets of wood? I am presuming this would be better than a simple batten framework with netting and the foam glued to the netting.
A proper remote recording booth...hmmm.
Well, there are two hurdles; external noise abatement and internal acoustical properties of the booth.
Density-Isolation-Density is the only known cure for the former. Judicious attention to geometrics and sound absorbing and diffusing surfaces address the second.
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[Ty Ford] "Well, there are two hurdles; external noise abatement and internal acoustical properties of the booth.
Density-Isolation-Density is the only known cure for the former."
Perhaps not. It might be possible to build a booth with active noise cancellation, similar to the active noise cancelling in Bose and Sennheiser headphones (and no doubt others as well). At least it might work for sufficiently low (long wavelength) frequencies.
That said, I've never seen it done. But someone has to be first, yes? Might be the OP.
I am OK for external noise, there is none. I want to tune the room to cancel any tendency to echo or boom, for example if at the event a guest voice is strong. I do not of course want to make the space offer dead sound with no resonance at all.
To refine my question, I am wondering if to deaden room echo only with the use of acoustic foam the thickness of the wood onto which the foam is fixed is not important. The room sound will be absorbed by the foam and not reflected back to the mic.
[Peter Derek] "I want to tune the room to cancel any tendency to echo or boom, for example if at the event a guest voice is strong. I do not of course want to make the space offer dead sound with no resonance at all."
If I'm doing it I want to make the space as dead as possible, reducing reflections as much as possible. The laws of physics are what they are. Small rooms (and what is a portable vocal booth but a really small room?) are notorious for room modes and rapid reflections. The rapid reflections are the major factor in "small room sound". If you have to record in a small room (including portable vocal booths) the best way to do it is to take out as much room sound as possible. Create the "space" you want in post by adding reverb.
The small microphone screen type devices are really only attenuating higher frequencies (1kHz and up). In the small "elevator" you describe, you're likely to have a lot of room modes (at higher frequencies than "normal"). You can control these to some extent with bass traps, but traps are typically made for lower frequencies, say below 250Hz. You'll want something to cover that 250-1000 Hz range as well. I'm not familiar with absorbers that work well in this range. These guys and their competitors might be able to help there:
I'm thinking somebody makes panels with available rolling stands. Roll it up against your problem wall(s), use 'em, roll them back to storage. That stuff is out there, just have to find it.
First, what Ty said.
I'll just add this.
Start with your ACTUAL needs.
What will you record? How often? What type of talent will you be working with or are you doing everything yourself or with non-professionals.
This stuff matters for the following reasons.
If you're recording characters that are whispering secrets, super isolation and tuning the booth may well be absolutely critical since you want the lowest possible noise floor, super clean signal gain and ultimate surrounding silence to get good results.
If you're working with amateurs who have poor articulation and/or poor vocal muscular support - again, you may need to value more complex recording chain, since things like a clean talkback chain may be critical as you coach them in real time and likely do many, many takes to get acceptable results.
But if you're working with professionals, who know how to do VO work - they'll be clear, articulate well, and their spoken volume will be robust - so you can often get a clear VOs in a quiet hotel room with a handheld stick mic. In fact, in that situation, a simple less sensitive stick mic may work far better than setting up an expensive Neumann condenser - since the super sensitive condenser will pick up EVERYTHING from the AC to the maid cart rolling down the hallway.
When you spend to build an ACTUAL voice booth - you're working and spending to eliminating ALL the potential issues, not just some of them for some circumstances. When people see VO booths on the internet, they think that this is the ONLY solution to getting good results and it's often not. You have to understand more than the physical structure. A perfect booth, wired improperly can be much worse than using a cheap all in one mic/recorder in a coat closet. This is just how it works.
Finally, as Ty suggests, anything "semi-portable" will be deficient in some areas. Typically portable means low mass. And guess what? Low frequency noise is ONLY abated via high mass.
All this means is that if you're near a busy street, or a flight corridor, or a subway line, you're going to have to do a TON more to make a "record whenever I want" situation than you'd need to spend in a quiet suburban neighborhood.
It's never ONE thing, it's everything working together.
The Recipe for a good VO? Good mic, good talent, good signal chain, good script, good person running things who knows what to listen for and when they hear something wrong, knows how to fix it.
My 2 cents after 30 plus years doing this type of work.
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Thank you very much - yes you guessed I am not able to determine who is being recorded.
When I myself record in various locations and studios I am surprised how I notice even small variances in the room acoustics.
Thank you again.
The major reason people use "portable" enclosures is to isolate from ambient noise. But since you state that you don't have ambient noise to deal with, then you are talking only about the internal acoustics of the space. As others have stated, this is rather a complex decision based on many factors not mentioned in your question.
I have found this interview to contain several useful gems of wisdom when designing a recording space:
Recording audio without metering and monitoring is exactly like framing and focusing without looking at the viewfinder.
Thank you all very much for your valuable comments.
These also especially remind me of the density/weight rules for sound absorption for which there is no workaround - it is going to be heavy or the results will come back with a vengeance.
So I have chosen construction materials using your advice and your notes, and the video also adds further details of value - Thank you.
100% You should be using those mic filter screens. Remember, in a less then ideal room, the less level you fire off into the room the better as it will be less activated.
In a less than ideal situation like this you aim for bass trapping first. Prioritise 3 points corners, then 2 point. Fill each of then. Then after that you just make it dead dead dead and go for maximum absorption.
This is not the approach you would use normally but for a situation like your that is what will give you the best result.
Once this is done your remaining problem area will be 130-300 hz, which you will be able to address nicely with EQ, as your bass has been trapped and your HMF and highs have been contained.