OK, I see your point. I can think of at least two ways to overcome it, but they take a fair amount of work, and so probably would only be used by a manufacturer. One would be to build an isolating fixture, perhaps putting the terminus into an anechoic chamber or outside a building wall. The other would be using two microphones and applying nearfield theory, (such as Keele's) to determine the relative contribution of each source. This is done routinely in large vented systems and multi-source arrays, and isn't that difficult.
So, let me think of the various TL's, (accepting the common usage of the term). No rankings or ratings here.
Fried's stuff. I had listened to it at many shows, but also, Bud became a casual friend at one point. He played several things for me, and I used one of his smaller designs at a trade show demo I was doing.
IMF stuff, but long ago.
PMC stuff. And I have had some discussions/debates with Loader.
Numerous smaller manufactuers and serious hobbyist designs heard over the years at trade shows, audio club lecture tours, client visits, etc.
My own efforts in the area, including a large TL done in college with friends, and the NHT VT-1, which used a small line terminated in a Helmholtz resonantor to allow one of the first videocentric, small column systems.
/k/
Getting an accurate measuement using a spl meter when the line terminus is 26" below the voice coil center on the sub. How do I know the woofer's sound isn't affecting the reading from line terminus.. They both measure the same spl. The spl coming from line terminus at the rear of the C3L enclosures is = to measurements from the front. All the damping placement in my first O4 enclosure were designed by the company. I am well from a very easily pleased listener. You listened to the Acoustic Research sound when you got interested in loudspeaker design. I was exposed to Fried's aperiodic loading in the B2 and C satellites and t-line of the model O. The t-line was not yet used for the midbass driver this was around 1986 Listening to the C3l and O4 enclosures is like now hear this. Do you recall which models of Fried-lines you have listened to over the years? I have not heard of the new owners desings. I dont' claim to be a genius designer. I can't claim to create the designs. Bud created his designs by expanding on other people's work. I understand what the designer achieved by comparing different designs. I have used this to create my own designs as have many former Fried kit owners. The best t-line designs I have heard are the C3L and O 4 enclosures with the various drivers Bud designed for their use.. The 2 way flat baffle on the Fried Studio IV does not have the off axis respone of the tweeter and mid range compared to the sloped front C3L. I have not heard other companies t-lines except the B&W Nautilus 801. Very few companies offer t-lines commercially. I prefer the Fried C6 and O6. The Fried lines sound more like real music then other companies speaker designs. I know I am being subjective You have probably heard more t-lines then I ever will being in the industry. What t-lines have you listened to over the years and your opinions of them?
