Active Absorbers

russbryant · 7th March 2003, 06:11 PM

Dredging up more of Nelson's past. I pulled the following quote from someone on the DIY list (old Bass list):

"Have you heard of active absorbers? Not me, but my colleagues seems to be familiar with this concept, and apparently the idea is 15 years old. It seems like the only logical solution to me.

Nelson Pass seems to have designed the "Shadow" by Phantom Acoustics. (anybody heard these?). Located in Auburn, California."

I searched around a little on the web but didn't turn up anything.

What's the scoop?

Thanks,

Russ in Tucson

russbryant · 7th March 2003, 06:14 PM

I'll read some of the reviews but would still like to hear from Nelson on this.

Thanks,

Russ

Mark A. Gulbrandsen · 7th March 2003, 08:17 PM

Yea, I recently looked at the patent for it on the patent web site....at least I think this is the one that has to do with that....
Try this link.....
Mark

http://patft.uspto.gov/netacgi/nph-P...AND&d=ptxt&s1='Pass,+Nelson'&OS="Pass,+Nelson"&RS="Pass,+Nelson"

Doesn't appear to work but go here to the quick and type in Pass, Nelson and you can grab it off the list that comes up.

http://patft.uspto.gov/netahtml/search-bool.html

djk · 9th March 2003, 05:37 AM

http://patft.uspto.gov/netacgi/nph-P...number=4899387

Nelson Pass · 9th March 2003, 05:22 PM

I have some material and reviews that I'll post on Monday
when I get my ftp working again.

Nelson Pass · 10th March 2003, 07:23 PM

OK, I got my ftp mojo working again.

Go over to www.passlabs.com/temp to see everything I've stuck up there, and look for the files starting with "Shadow" to see a paper and a review. Some of these
are JPEG, some TIFF, some both.

Fred Dieckmann · 10th March 2003, 08:09 PM

"OK, I got my ftp mojo working again."

Did it make you happy as the man below?

Nelson Pass · 10th March 2003, 08:23 PM

I think we have the same mojo, but he looks to have
more hair, and it's not gray, either.

Welcome back Fred.

russbryant · 10th March 2003, 09:47 PM

Thanks Nelson.

Mark A. Gulbrandsen · 11th March 2003, 03:52 AM

A few years ago I worked on an 8 screen theatre design in Johnson Creek, WI....2 screens were THX and the HVAC contractor screwed up big time. He guaranteed that the systems would meet NC25, NC30 is required to pass crertification, but they came out more like NC38 or there abouts. The HVAC contractor was faced with the dillemma of making them quiet, fortunately I was not.....I was only the sound system and projection equipment supplier/installer. What he ended up doing was to have two active acoustical noise camncellation systems installed inside the duct work. These active systems, when turned on and calibrated, actually got the systems down to NC28!! THX was skeptical as this had never been done before......not the normal fix for this sort of problem, but they ultimately, after re-testing the NC level, accepted them as part of the system. Everyone lived happily, ever after, the theatre got its THX certification and the HVAC contractor got stuck with the bill, and installation for the devices!
Yes indeed these things work very well!!!
Mark

P.S. The company that made the noise control devices was Digisonics in Middleton, WI.

7th March 2003, 06:11 PM	#1
russbryant diyAudio Member Join Date: Oct 2002 Location: Tucson, AZ	Active Absorbers Dredging up more of Nelson's past. I pulled the following quote from someone on the DIY list (old Bass list): "Have you heard of active absorbers? Not me, but my colleagues seems to be familiar with this concept, and apparently the idea is 15 years old. It seems like the only logical solution to me. Nelson Pass seems to have designed the "Shadow" by Phantom Acoustics. (anybody heard these?). Located in Auburn, California." I searched around a little on the web but didn't turn up anything. What's the scoop? Thanks, Russ in Tucson

7th March 2003, 06:14 PM	#2
russbryant diyAudio Member Join Date: Oct 2002 Location: Tucson, AZ	Yikes!! Did a new search and found some info. I'll read some of the reviews but would still like to hear from Nelson on this. Thanks, Russ

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7th March 2003, 08:17 PM	#3
Mark A. Gulbrandsen diyAudio Member Join Date: Sep 2001 Location: Salt Lake City	Yea, I recently looked at the patent for it on the patent web site....at least I think this is the one that has to do with that.... Try this link..... Mark http://patft.uspto.gov/netacgi/nph-P...AND&d=ptxt&s1='Pass,+Nelson'&OS="Pass,+Nelson"&RS="Pass,+Nelson" Doesn't appear to work but go here to the quick and type in Pass, Nelson and you can grab it off the list that comes up. http://patft.uspto.gov/netahtml/search-bool.html

9th March 2003, 05:37 AM	#4
djk diyAudio Member Join Date: Feb 2001 Location: USA	http://patft.uspto.gov/netacgi/nph-P...number=4899387

9th March 2003, 05:22 PM	#5
Nelson Pass The one and only Join Date: Mar 2001	I have some material and reviews that I'll post on Monday when I get my ftp working again.

10th March 2003, 07:23 PM	#6
Nelson Pass The one and only Join Date: Mar 2001	OK, I got my ftp mojo working again. Go over to www.passlabs.com/temp to see everything I've stuck up there, and look for the files starting with "Shadow" to see a paper and a review. Some of these are JPEG, some TIFF, some both.

10th March 2003, 08:23 PM	#8
Nelson Pass The one and only Join Date: Mar 2001	I think we have the same mojo, but he looks to have more hair, and it's not gray, either. Welcome back Fred.

10th March 2003, 09:47 PM	#9
russbryant diyAudio Member Join Date: Oct 2002 Location: Tucson, AZ	Thanks Nelson.

11th March 2003, 03:52 AM	#10
Mark A. Gulbrandsen diyAudio Member Join Date: Sep 2001 Location: Salt Lake City	A few years ago I worked on an 8 screen theatre design in Johnson Creek, WI....2 screens were THX and the HVAC contractor screwed up big time. He guaranteed that the systems would meet NC25, NC30 is required to pass crertification, but they came out more like NC38 or there abouts. The HVAC contractor was faced with the dillemma of making them quiet, fortunately I was not.....I was only the sound system and projection equipment supplier/installer. What he ended up doing was to have two active acoustical noise camncellation systems installed inside the duct work. These active systems, when turned on and calibrated, actually got the systems down to NC28!! THX was skeptical as this had never been done before......not the normal fix for this sort of problem, but they ultimately, after re-testing the NC level, accepted them as part of the system. Everyone lived happily, ever after, the theatre got its THX certification and the HVAC contractor got stuck with the bill, and installation for the devices! Yes indeed these things work very well!!! Mark P.S. The company that made the noise control devices was Digisonics in Middleton, WI.

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