FRANCISCO%FILIP0.LIPUC.RCCN.PT@CUNYVM.CUNY.EDU (FRANCISCO FRAGA) (02/01/91)
I have recently read (Stereophile December 1990) a review of a software program called the Listening Room, a room analysis program. I found the software quite interesting. I have done some calculations long time ago using Lotus 1-2-3, but, due to time constraints, it is still unfinished. But, unhappily, the reviewr says " the programm author does not currently recommend it for use with dipoles", and my speakers are dipoles (Quad ELS63). If some one knows of a similar programm working with dipoles I would like to hear about. By the way, what are the Tube Traps and how do they work? Are they passive or they have amplifiers inside? ........................................................ Francisco A. F. Fraga Dept. Physics Univ. Coimbra 3000 Coimbra PORTUGAL tel. 351-39-34668 fax 351-39-29158 FRANCISCO@FILIP0.LIPUC.RCCN.PT
tness@convex.COM (Thomas Ness) (02/06/91)
In article <9318@uwm.edu> nichols@vms.macc.wisc.edu (Dennis Nichols, MACC) writes: >Now what I want to know is how do I construct devices with the same >function as TubeTraps, that is, home-built tube traps. Any published >references? Any of you out there tried this? I had a dealer who doesn't >stock them suggest that I could build some but (understandably) he >wasn't about to say more than that. > ># Dennis Nichols 1210 West Dayton St. 608-262-1936 >| MACC Univ of Wisconsin-Madison Madison, WI 53706 nichols@macc.wisc.edu >#--------# Academic Computing Center UNITED STATES nichols@wiscmacc.bitnet I have built 16 full round tubes and 4 half round tubes since I read in rec.audio what they are and how they are built. I use them to make a narrow room seem wider and to approximate a live end and dead end room. I have had very good results with them and my musician guests seem to agree. The core of a tubular trap is made of fiber glass steam pipe insulation. This\ comes in various sizes. All are about 3' in length but inside diameters and wall thickness vary. I have used a 3' x 9"id x 1" wall tube. I paid about $44.00 per box of four. These should be available from specialty insulation suppliers. I found one in Atlanta that was called AC&S. I know that they were sold and I don't know what their new name is. It is possible that AC&S is still used in many parts of the country. (They were a nation wide firm) It is worth checking to see if the major insulation contractors in your area are willing to provide a vector. I also had access to a discount drapry fabric shop in Atlanta. I was able to buy remants of good fabric for about $5/yd. If you do rough calculations you will see that it takes about 1yd. per tube. (BTW: Forsythe Fabrics, behind Ga. Tech is my source, for folks in the Atlanta area) I used construction gule in a tube because it was easy to apply and had the bulk to glue the rough fabric to the rough fiber glass. I used ordinary sewing pins to hold the fabric while it set. My half tubes are cut from whole tubes with a razor knife. I bought oak finished boards from Home Depot to top the tubes. I think that they look good. My materials cost was about $20 each tube. The list price is $175 for these from ASC. I think that these are called 3' x 11" in the ASC catalog since they seem to refer to outside diameter. I could be wrong. I removed the paper from the outside of 4 of my tubes but left it on for the others. I have read ASC's literature and I believe that the wrapper is what ASC calls the "Limp Mass Crossover". I think that this means that the fiberglass is more absorbent for high frequencies, but the paper coating blocks these frequencies. This would not effect the low frequency response of the tube since these frequencies rely on the RC effect of the tube more than simple surface absorption. If I am wrong, politely let me know. If you want to know more, let me know. Thom Ness tness@convex.com
tness@convex.COM (Thomas Ness) (02/07/91)
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