Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Equipment & Tools From test equipment to hand tools

Makeshift Anechoic Chamber
Makeshift Anechoic Chamber
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Thread Tools Search this Thread
Old 31st March 2012, 12:35 PM   #11
tvrgeek is offline tvrgeek  United States
diyAudio Member
Join Date: Dec 2009
Location: Md
Originally Posted by epicyclic View Post
Hi Speedskater

" physically ill " ...interesting , what do those who get ill put this experience down to ? / or what is the understood reason .
Our brain gets upset when our senses are confused. When we see the size of a room, we expect to hear reflections from a room that size. Same problem with sea sickness. What we see and what our inner ear senses conflicts. I find a chamber an interesting experience. Same with cave black.
  Reply With Quote
Old 31st March 2012, 02:18 PM   #12
PChi is offline PChi  United Kingdom
diyAudio Member
Join Date: Jan 2012
Location: Staines, UK
I have only been in an RF anechoic chamber which was quite effective at audio frequencies. The low background noise and lack of reverberation is weird. The RF one I was in had a small area of wooden floor above the wedges, OK for RF but not great for audio. I guess that in the audio chambers you are walking on a grid, unnerving. Also there is going to be zero natural light and if the door is closed very little air circulation or ventilation. I believe that the RF chambers do have an RF screened ventilation system but that's not going to be good enough for audio measurements.
  Reply With Quote
Old 2nd April 2012, 03:29 PM   #13
epicyclic is offline epicyclic  United Kingdom
diyAudio Member
Join Date: Jan 2012
Thanks for the feedback on the effects of being inside an anechoic chamber.
  Reply With Quote
Old 3rd April 2012, 02:08 PM   #14
macboy is offline macboy  Canada
diyAudio Member
Join Date: Oct 2003
Location: Ottawa, Canada
That 'egg crate' style foam will do much less good than you think. I would suggest something a lot thicker and more dense, like Roxul (aka Rock Wool) "Safe N Sound" insulation. It is similar to fiberglass batting insulation, but is made from stone fibers (no, not asbestos). It will cost you roughly 50 cents per sq foot, and is about 3.5 inch thick. I recently finished my basement into a home theatre/listening room and used this stuff in the all the walls and ceiling as part of my soundproofing. Before the drywall went up, it was similar to an anechoic chamber in there, very dead sounding.
  Reply With Quote
Old 3rd April 2012, 03:00 PM   #15
Ouroboros is offline Ouroboros  England
diyAudio Member
Ouroboros's Avatar
Join Date: Dec 2003
Location: Nottingham UK
I use a purpose-designed anechoic chamber at work which is a 3.5 x 3.5 x 3.5 metre cube internally, with 350mm deep foam wedges on the walls and ceiling and 180mm foam on the floor. This is only anechoic down to around 300Hz. For anything lower you have to increase the dimensions. In my days with DECT handset testing I used an old British Telecom "Blue Box" (a small 1.5 metre cube foam-damped box), but these were getting inaccurate for measurements below 500Hz. I think trying to do anything DIY is not going to give usable results.
  Reply With Quote
Old 3rd April 2012, 04:36 PM   #16
tuxedocivic is offline tuxedocivic  Canada
diyAudio Member
tuxedocivic's Avatar
Join Date: Jan 2011
Location: Ladysmith, BC
Any idea how loud it is outside? Could you get away with testing at very high volume? Perhaps at high SPL the signal would swamp out any noise. At least good enough. The lower frequencies are usually the biggest issue. So depends what you're trying to get. You could also take your equipment to a large parking lot someplace at night. Cops might wonder what you're up to though.
  Reply With Quote
Old 3rd April 2012, 09:02 PM   #17
DrBoar is offline DrBoar  Sweden
diyAudio Member
DrBoar's Avatar
Join Date: Apr 2003
Location: Stockholm
An anechoic chamber is a reflectionless room, ie sounds generated inside the is not bounced around in the room. A sound proofed room is a very different animal made to stop sounds coming outod the room/ in to the room.

The simplest solution is to play loud enough while you measure. Sounds/vibrations coming through the walls and floor is something you can do nothing about unless you build a new room floating inside the current room.

Sounds coming hrough an outer wall or window only can be greatly reduced by building a wall spaced away from the offending wall. Double layer of plasterboard well sealed is important. Having some fiber glass or rockwool in between is OK. This material will lower the Q of the resonanses of the plasterboard but not stop any tranmission of sound across the space. There is a lot of information regarding soundproofing. What you really need are as many sealed walls as possible with "resonable masses" A double wall with staggered joists with one row for the inner wall and an other not connected to the first row for the outer wall with double layer plasterboard, will be quite good. This 2+2 plasterboard is way better than say a 8 layers of board on a single wall
  Reply With Quote
Old 4th April 2012, 01:00 AM   #18
tvrgeek is offline tvrgeek  United States
diyAudio Member
Join Date: Dec 2009
Location: Md
If you are not designing traducers, you don't need a chamber. Have you read D'Apollito's book yet? Unless of course you are building a speaker to use inside a chamber in which case you would already have one. The ROOM IS PART OF THE SPEAKER.

You need about 9 or 10 dB margin for testing. I start at 1 watt, so that is between 85 and 90 dB. You can do that outside usually, but it may cause some visits. Test a sub for breakup? Don't even think about that at night.
  Reply With Quote


Makeshift Anechoic ChamberHide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Check my First Box & Measure in anechoic chamber endrek Subwoofers 54 20th September 2013 03:58 AM
makeshift di Al Swenson Construction Tips 12 7th April 2011 11:53 PM
DIY anechoic chamber! Snickers-is Multi-Way 33 13th March 2005 08:30 PM
anechoic jig speekergeek Multi-Way 9 15th December 2003 10:10 PM
design of anechoic cabinet capslock Multi-Way 0 21st March 2003 09:29 AM

New To Site? Need Help?

All times are GMT. The time now is 11:56 PM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.79%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio