Acoustic treatment

Hello clearthink,

     Okay, wiseguy.  There's lots of scientific White Papers on this subject from Dr. Earl Geddes, Dr. Floyd Toole and others.  These are easier to read, however.  I'd read them in order, Mehlau first and then the Dagogo interview with Geddes last.

https://mehlau.net/audio/multisub_geddes/


http://www.dagogo.com/View-Article.asp?hArticle=1047)


Later,
Tim

This is one of the weirdest fantasy land treads I've ever read on A-Gon.So much bad information that it should be deleted.  Magic thimbles as room treatment?  Shear pressures?  Electromagnetism in sound waves? 
Can't hear bass below 80hz?  That knuckle head needs to get his hearing checked.

MurphyTheCat nailed it.

OP, Read the tests on BobGold's site to get information about which materials work better at absorbing bass.  You are on the right track.  The source of the problem is the room.  Fix that. 
Ignore all the other blather about hocus pocus mystical forces at work.

noble100"Okay, wiseguy. There's lots of scientific White Papers on this subject from Dr. Earl Geddes, Dr. Floyd Toole and others. These are easier to read"

These are very nice links with lost of words and opinions but they are completely and entirely lacking any data, studies, scientific tests, listening tests, research, or references to support you're repeated claims that all bass below 100 or 80Hz is monophonic while conversely others have pointed you to such reliable, repeatable, reproducable data that is very strange that you cling to this notion and again I do not have a firm opinion on this matter but you have failed to support your claim with anything other than silly claims like "it has been shown" and "acousticians have long known" etc.

Hello clearthink,

     This is a paper by Todd Welti of Harman International, who studied under Dr. Earl Geddes.  He specifically also states that bass under 80 Hz is not directional or localized.

ttps://www.harman.com/sites/default/files/multsubs_0.pdf

clearthink,

     I'm on another thread right now posting back and forth with Duke Lejeune, Audio Kinesis owner who designed and sells the Swarm 4-sub DBA system I use.  Here's a post quote from him today:

"@noble100 wrote: "Duke... I was hoping to get your honest opinion on my thoughts on how I understand multiple sub systems function in general as well as my understanding of how bass is recorded on CDs and vinyl."  

In general I agree with what you wrote, so let me just toss out a few comments.
" We all are unable to localize deep bass frequency soundwaves..."  

My understanding is that’s generally true in a room. The figure I use is 80 Hz, rather than 100 Hz. I think Floyd Toole uses 80 Hz. This doesn’t necessarily mean that one cannot detect the location of a sub which is crossed over significantly lower, say at 40 Hz, because crossovers are not brick walls, so upper bass/lower midrange energy can give away a sub’s location if it comes through loud enough. Therefore in my opinion a steep lowpass filter on the sub helps to hide its location.  

"the bass is summed to mono on frequencies below 100 Hz on all vinyl and cd recordings."  

I wouldn’t say "all", but I would say "almost all". (If we’re talking about a Swarm/DEBRA system, a second amp can be added to give you true stereo bass).

"Our brains are able to associate the fundamental deep bass frequencies reproduced by the subs, that are not able to be localized, with the deep bass’s higher harmonic frequencies, that extend well beyond 100 Hz, which are reproduced by the main speakers that are able to be localized. This psychoacoustic association allows us to localize the deep bass in the soundstage, for example the kick drum is located in the rear center and the upright bass is located in the front to the left, which would not be otherwise possible without this psychoacoustic association our brain’s are capable of."

I agree.   

Duke"

Here's the thread link:
https://forum.audiogon.com/discussions/searching-for-matching-subwoofer-solution?page=2

Tim