| Boundary Effect [message #339987] |
Fri, 09 May 2008 07:45  |
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 Ian Visible
Messages: 82
Registered: November 2005
Location: Sussex, UK |
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Could someone explain, in terms that can be understood by a simpleton, the boundary effect please?
I've read a quite a few posts that mention it both in relation to bass trapping and to mic placement, and the more I read, the more confused I become.
What's it all about, Alfie?
Josh
"An infinite swarm of haircuts and anuses, that's humankind for you." - Charlie Brooker, 2008.
http://songramp.com/Josh
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| Re: Boundary Effect [message #340031 is a reply to message #339987 ] |
Fri, 09 May 2008 11:16  |
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gullfo
Messages: 125
Registered: February 2005
Location: Old Tappan, NJ USA |
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from a mic position perspective. if you simply stand just off center in a room and speak, then shift sideways to a wall, you'll hear a distinct shift in what you hear. this is because the sound is bouncing off the wall and into your ear and mixing different frequencies at various phases as you do it. probably the simplest example of comb filtering. no equipment other than your ears needed. however, your ears will try to compensate for it, so the effect is short lived. a microphone has no such compensation and it will faithfully record the effect - not good unless you want it.
from a speaker perspective, the bouncing not only introduces cancellations and reinforcements, but changes the loading on the speaker which can cause the power needed to drive it to change and result in additional distortion. depending on where the speaker in placed front-back, side-side, has different effects on its response which is one reason for having adjustments on the speaker to cut or boost bass. a baffle mounted speaker designed for open mounting will experience a bass boost, and depending on how the baffle is constructed, you could also shift the apparent crossover points in a bad way.
Seigfried Linkwitz and Phillip Newell has some excellent treatises on this subject...
Glenn Stanton
www.runnel.com/
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| Re: Boundary Effect [message #341952 is a reply to message #339987 ] |
Fri, 16 May 2008 08:41 |
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Ian Visible
Messages: 82
Registered: November 2005
Location: Sussex, UK |
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That's a splendid page!
Thank you kindly!
Josh
"An infinite swarm of haircuts and anuses, that's humankind for you." - Charlie Brooker, 2008.
http://songramp.com/Josh
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Re: Boundary Effect
