Fried "Line Tunnel" Technology

[BAM]

I just learned about the bass-loading technology that was used on my parents' Fried Model Q speakers. It is like a tuned port with a block of foam at the end of it. This supposedly mimicks the bass loading characteristics of a transmission line with a much simpler cabinet. Does anyone know how this technology might be applied to DIY designs?

[planet10]

This is aperiodic loading of the cabinet.

There aren't a lot of formal rules for designing these, but other examples are Goodmans with the ARU (acoustic resistance unit) and the Dynaco A25.

dave

[Nat Eddy]

I had a pair of Qs of the earliest vintage -- very nice for size and price. I remember that Bud Fried suggested that you could do some tuning yourself by removing some of the foam. This suggests to me that there is some element of cut-and-try involved, and perhaps you could simply experiement. Or you might try contacting Bud himself. Fried sold some designs as kits, and the instructions might offer some suggestions.

[BAM]

My mom's Q's were also of the earliest vintage. I still have one of the original woofers and both the original tweeters, but when I started driving them wit modern high-powered recievers, the drivers started to show their age. The tweeters started rattling, and the rubber surround on one of the woofers separated from the cone. We replaced the other cone with a Radio Shack 8" and found we got very loud bass when we unplugged the Line Tunnel and allowed it to act as a reflex port. Could you recommend a good type of woofer to stick in there for near-original performance? I may also do a new crossover for them, but I need to find a nice woofer and a dome tweeter that has a certain faceplate dimension that is slightly larger than the 4-1/2" that is most common. I have a couple of Pioneer phenolic ring cone tweeters that I use in there.

[GRollins]

For a while Fried was into using Dalesford woofers, but whether that's what's in your Q's I couldn't say. It's almost certain that they aren't KEF drivers, as the Q came later in the history of the company.
I believe Dalesford is out of business, but I haven't checked in a while.
Does the driver have a paper cone or plastic? I seem to remember paper for the Q.

Grey

[BAM]

It is a paper cone with a porous fabric dust cap. Supposedly the paper is impregnated with minerals or some such treatment that is supposed to give it a more natural transient response or something. It has a metal trim ring, but that can be removed and I don't know if it was part of the original driver or just added to cover up some sort of seam or something. What I'm looking for is a driver I can throw into the unique Line Tunnel enclosure and get similar performance.

I heard somewhere that Fried is making a comeback pretty soon, with the Vahalla System, which, as far as I can gather, is like the old model T subwoofer (the big coffin with separate TLs for right and left) and the small satellites. I wonder if they will revive the Q, and what other brands of speaker products they will be competing with. Back in the Q's day, a review compared it favorably above the Larger Advent Loudspeakers for music listening, but the Larger Advents were better for shaking the walls. I know someone whose parents have a pair of Larger Advents, and they are quite excellent, for as old as they are.

[Nat Eddy]

I believe many of the Fried woofers were made by Charbonneau (sp?) out in the midwest. There was a dustup in Speaker Builder between Bud Fried and Gary Gallo about whether they were stock or modified, Gary having assumed that since they looked stock they probably were, and Bud correcting him. I have no idea what would be a good replacement.
I do not think phenolic ring tweeters would be an adequate substitute for the original tweeter. I thought the originals were HiQuphon (sp? again) a french company, but apparently this was only true of the more expensive Frieds.
Sorry to have been less than no help, as all I've done is rain on your parade.