VO-BB - 20 YEARS OLD!

[asnively]

Mike is some kind of wizard, I tell ya!
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[Hestoft]

That he is for sure. I regret being too shy to consult him BEFORE I started the build, but I am sure he can come up with a few tricks to help me out.

Frankly, I am puzzled by the ambient noise readings I am getting and windering if anyone else had had similar issues. I show about 53db of ambient noise everywhere in the studio, but the weird thing is the frequency distribution. I get most of it (40db) at 20Hz with lesser amounts up to about 70Hz, then everything above that is below 30db and the ability of my instrument to measure it, until you get to 20kHz, where I get about 35db, strangely enough, from my computer monitor!

I am wondering what kind of readings others may be getting for ambient levels in their studios and what constitutes an acceptable reading. Even with no low cut filtering, when levels are set correctly for my voice, the noise floor reads -60db, but is still slightly audible and benefits from noise gating.

Secondly, I am wondering what in the HECK is causing a regular thrumming at 20db in my house. That has got to be below the frequency that my window air conditioner puts out and the thrumming is too regular to be random traffic rumble. I suspect the factory down the street, but they shut down late at night and I still hear it. Weird. Any suggestions appreciated.
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Ralf-Finn Hestoft
The Great Dane

[Mike Sommer]

Firstly in your sound files you sent me, I hear air moving. The ducting your pulling into the room terminates right next to your mic- BIG mistake.
(And indeed the duct does look like the abyss water tentacle)

Turn off of the AC, move the computer out of the room, and shut off everything in the house that makes noise.

Those SPL meters are generally useless in tuning a room, they may give you peak levels but they don't give you nulls or a picture of what is going on. And unless you're running sweeping tones, you're just getting a very small brushstroke of a larger picture. What's possibly happening is that you're getting some frequency doubling, and you have a deep null in the room. But I don't know how you come to these numbers, other than ambient readings which is nothing more than unwanted sound. As I said turn everything off in the house, then work backwards to seek out the mystery sound.

You've purchased a lot of expensive treatment, yet you defeat it with all those hard reflective surfaces-- Shelving, cabinets, plastic containers, metal file cabinets, and more monitors than Houston Control. Clear it out. Let's get you down to absolute necessities: desk, mic, one monitor, keyboard, mouse, copy stand, light-- the stuff you only need to do voice over.

If your shelves were full of nicknacks, books, stuffed animals and such I would say keep it. These this offer diffusion and absorption like the shelves in my studio:

Even here I have moveable gobos, so that I can contour the sound if I want it a little dryer, or I can turn and move
But everything in your booth is hard a reflective and boxes; these things reflect, ring and resonate.

After you do all that let's get new ambient room recordings and some vocal recordings.
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The Blog:
http://voiceoveraudio.blogspot.com/

Acoustics are counter-intuitive. If one thing is certain about acoustics, it is that if anything seems obvious it is probably wrong.

[Hestoft]

Mike,

Thanks for the tips. I do use the room for editing photos as well as voiceover, hence the multiple monitors. I had covered everything with sound blankets to minimize the hard surface reflections, but they seemed to exaggerate the ambient noise by 5db or so, but I could me mistaken. I will also move the ventilation.

I am currently sitting in the room with everything off in the house (finally it is cool enough in Chicago to go without air conditioning for a while) and I still see some very low frequency ambient noise. I was futzing around with the meter this morning, and it seems to be most concentrated in the tool room to the West of the studio, where a small interior brick wall meets the foundation. There I get readings of 50db from 20Hz to 60Hz. I did place superchunks in that particular corner, but don't think they are doing much as the frequencies are too low. I really think that this remaining ambient noise comes in from the outside and reverberates around the foundation and all I can do is absorb as much of it as possible inside the studio itself.

So, I will superchunk my South wall, since placing the sheets of 705 there helped considerably, hang the sound blankets to mute any hard surface reflections, then give you some new recordings of noise and some vocal tests.

Thanks again for taking the time to help a brother out!
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Ralf-Finn Hestoft
The Great Dane

[Mike Sommer]

[Hestoft]

Michael,

Using a high-pass filter was where I was heading as well. It is interesting to note, however, that adding the superchunks and additional sheets of 705 to my south wall, DID lower the level of the ambient noise to make it almost inaudible when levels are set to just record my voice.

However, I still have some issues with the room as you pointed out. I have sent you an email with F's of waterfall and reverberation plots from the room that seem to show a very large bump in the level of bass at around 80Hz to 100Hz. However, I am not really sure if I did the readings correctly and I really don't know how to interpret them. I do know that, near the ceiling, in the position I hope to record in, things sound a bit boomy,even to my bad ears.

So I thought I would get some suggestions from you, if you have some, to mitigate that before I posted more sound files and I think we are agreed that we can forgo the ambient noise files altogether.

Thanks again and I look forward to your wise suggestions. I just hope I don't have to end up in a 2' x 2' space surrounded by hundreds of bass traps!
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Ralf-Finn Hestoft
The Great Dane

[Mike Sommer]

Well, that's why proper construction should be implemented from the beginning, so you wont end up with a 2' x 2' space.

The frequency and intensity of the noise was such, that you got lucky. It's not impossible to reduce the noise with insulation it's just not the best way to go about it.

As an experiment I've taken bails of rigid insulation and piled them around and on top of a very noisy air compressor. It reduced the sound tremendously, but it did not stop it. We put the same compressor in a properly constructed room, and you could not even tell it was on. Nothing.

I think this thread is a good example of why one should get the advice needed, lay out a plan before one goes off to builds a booth. This is why when I build a booth, I come out, listen, listen some more, ask questions, listen some more and ask more questions. Then the planing begins to address the environmental conditions where the booth is going to be.



What happens instead of working, one has to pour more money and time into solving problems that have been there from the beginning.
_________________
The Blog:
http://voiceoveraudio.blogspot.com/

Acoustics are counter-intuitive. If one thing is certain about acoustics, it is that if anything seems obvious it is probably wrong.