VO-BB - 20 YEARS OLD!

[yarg28]

When I built my booth a few months back there were a few questions about my choice to not include ventilation. I wanted to update my status.

I still do not have a ventilation system. I've worked in the booth for up to an hour without opening the door and havent had any issues yet.

Only one time was I in there for a bit over an hour and had to crack the door for about ten seconds to recycle air. Then right back to work.

I'm still happy that I chose to wait/ignore it.

[vkuehn]

Come July and August, you will find out if the no-fan mode is going to work long term.

Back in January Lee Gordon posted a picture and model number of a very practical fan if you end up eventually needing one.

Check out FanTech http://www.ecomfort.com/fan/fantech-inline-duct-fans.html?utm_source=gemini&utm_medium=cpc&utm_campaign=brand+fantech+categories&var1=ecomfortusa&var2=geminisearch&var3=fantech

Locate it near the floor to pick up the coolest possible air. Use a 4 or 6 inch flexible duct with the aluminum foil outher skin and make it 20 feet long or so and there will be no noise!

[Lee Gordon]

A caveat about the fan and ventilation. While that fan is, indeed, quiet as a mouse, I do not run it while recording because you can hear the rush of air being drawn through the exhaust duct, which I located at eye level, directly behind my mic. I plan to swap the input and output in my booth so that the fan will be connected to the present inlet duct, which is down near the floor and which, I believe is the quieter of the two. But I haven't done that yet, so the jury is still out.
_________________
Lee Gordon, O.A.V.
Voice President of the United States
www.leegordonproductions.com
Twitter: @LeeGordonVoice

[vkuehn]

I'm a curious kind of person and there are some "facts of life" that always interest me. And among those facts are: 1. how fast can we move air through a space, a duct, before it becomes noisy. 2. How many times per hour do we need a "complete change of air" in a given space to have control over the temperature and freshness of the air.

40 years ago I could go to the public library and find articles on those topics in reference books and magazines for the HVAC industry and architects. Today, not so much. And I don't know that the old numbers were accurate but here goes. Some of the fresh incoming air may immediately enter the "return air" and some air may just lay in the corner forever, but you start by calcualating how many cubic feet are in your room and you declare you want to move enough air to "have a complete turnover" 6 or 8 times per hour. Now you now how much air will be coming through the duct into your space. You want that air moving through the duct at no more than maybe 100 linear feet per minute but be prepared to deal with a max of 200 or 300 if you can live with some wind noise. Now that you know the volume of the air needed you can calculate the what size input and output duct will be needed to move that much air moving at that speed.

Now that you can calculate the diameter of the duct to move that amount of air and that speed, you want the insulation lined duct to be at least 10 times as long as it's diameter so if serves as a muffler to the sound of the air moving, and any noise coming from the fan and from other outlets (other rooms).

The typical HVAC install tends to involve air moving at maybe 1,200 feet per minute.... and we wonder what makes it so noisy!

Again, my numbers are old, old, old school. If anyone comes across more current articles or books on the subject, please share a link to them or the name of the book. My curiosity on this subject just never ends.

And as Lee has learned from experience, think long and hard about WHERE the air input and outlet are going to be in your recording space. Your mic doesn't like either one of them so keep them and the mic away from each other.

[Monk]

There is a fan out there,

http://www.industrialfansdirect.com/SP-TD-100XS.html?gclid=CjwKEAjwguu5BRDq8uSKhaKIzDkSJACQ7WJlKwTKH1k7BLSlOm7fz2wdbLEobJD04ODeS32SsiO9kRoCvAHw_wcB

that's quiet, and then if you scale up the 4" duct work to a baffle box and a large vent, effectively increasing the volume it has to travel through, which slows the airspeed, decreasing the noise. Also make sure the vent doesn't have tiny holes that will whistle.
_________________
Company, villainous company, hath been the spoil of me...

www.monksvoice.com

[vkuehn]

Good catch there, Monk. I poked around their website and found a calculator and a crossover chart for converting noise levels from SONES to DBA. Unfortunately, they choose to NOT give a sound rating to their equipment models. But the S in the XS part of the model number may indicate that it is more SILENT that other models they sell. Their literature talks a lot of "silence" and quiet.

Their target market seems to be bathroom ventilation and so much of the equipment to evacuate bathrooms is noisy! I guess people like that to some extent... the noise of the fans masks noises you don't want people hearing.

When life seems to be running a bit slower than normal around here, I may call them and see if any humans on the phone will talk noise levels, and do they have another model focused on another market (other than bathrooms) that might be even quieter.

[Lee Gordon]

My fan is super quiet and I have baffle boxes on both the intake and exhaust sides. I think I may have to sacrifice some aesthetics and remove the grills from the duct openings inside the booth. They are probably effectively acting as those small holes Monk mentioned.

By the way, I'm not as concerned with exchanging the air inside my booth. After all, its total volume is only 80 cubic feet. I can open the door for a few seconds or run the fan for less than a minute to completely change the air. My ventilation is more about getting the temperature down.
_________________
Lee Gordon, O.A.V.
Voice President of the United States
www.leegordonproductions.com
Twitter: @LeeGordonVoice