Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uwm.edu!csd4.csd.uwm.edu!info-high-audio-request
From: tness@convex.COM (Thomas Ness)
Newsgroups: rec.audio.high-end
Subject: Re: room analysis software
Message-ID: <9398@uwm.edu>
Date: 7 Feb 91 13:55:05 GMT
Sender: news@uwm.edu
Lines: 57
Approved: tjk@csd4.csd.uwm.edu
Originator: tjk@csd4.csd.uwm.edu

I tried to include everything that I knew about building tubular traps in
my posting the other day. I tried several different construction methods
and material combinations when I built my tubular traps. I tried to cover all
of my design decisions in my post. I tried....

Of course, the first person to email me about this posting hit me with a
question I had not considered.  He wanted to know how to use tubular traps.
USE THEM, I though you wanted to make them!

I have used tubular traps in three rooms. I lived in Atlanta until recently.
I used the traps in my studio control room. I used four full traps against
the wall between my speakers. I thought I noticed an improvement in the bass
after I placed these traps. This might be because I was preventing the
reflection of bass frequencies from this wall. For reference, my speakers 
are Tannoy SGM-10B studio reference monitors. I had them on omnimounts
that held them at ear level and away from the wall by about 1'. The shape of
the room was such that there was not a wall behind or beside my speakers to
the outside. Hard to describe, simple in actual practise.

I also used tubular traps (half traps) along the side walls that existed in
the room. This room was wider than it was long, so I never really thought
that I had a problem with strong early reflections from the side walls. As
I tried to describe above, the speaker wall was free standing from these side
walls. I did not think that these tubes were very effective, but since they
were cheap, what the heck? 

I have used tubular traps to improve the sound of my isolation room (really 
a separate building). Prior to installing the traps I had a midrange problem
caused by some unfortunate dimensions. The eigenmodes were very close to the
same frequencies. I used to have to use a lot of EQ to try to get a good
vocal sound out of the room. After the traps, I was able to avoid all EQ and
still get a very good sound. Also, the room had few good spots and many bad
spots before the tubes, but was much more even after the tubes. My use there
was in all eight triple corners. Now you see why I built so many traps. 

I am now in Colorado in temporary housing. I will be for some months to come.
I have the studio set up and operating in a room in my house. The room is
narrow. I have tubes in the triple corners above and behind the speakers 
as well as along the sides of the room. I have the end of the room with the
speakers well damped by the tubes and carpet and rugs. The end with the
recorders and keyboards and such has masonite floor boards and no other
treatment. It sounds good. I have musicians over nightly. They comment on 
the sound. I find the room to be a good place to work. I don't know the
actual dimensions of the room I am currently using.

Another email poster asked if I had a copy of the original post. I was not 
sure which post he meant. If he meant the post from rec.audio explaining 
how tube traps are made, I don't have it. Maybe someone else does, and would
post it. If he meant the post from the friendly dealer in the U.S. Southwest
that explained the RC nature of tubular traps, I did not save it either.
Possibly someone else has it, and would be able to help.

Any other questions?


Thom Ness
tness@convex.com