This is a preview picture of the bipolar alphaTLs that i built for my brother. I'm putting together a page for the TL site with more details (and a bigger picture ).
This is a "Frugal-phile(tm)" class speaker, and despite still needing some detail work they sound very crediable.
dave
This is a "Frugal-phile(tm)" class speaker, and despite still needing some detail work they sound very crediable.
dave
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Re: ALPHA
the Cherry stain gives them the lovely reddish colour -- something that so far has gotten very high SAF (across a sample set of a number of Ss)
BTW i get no credit with how they look, ChrisB is the cabinet maker. I send him drawings (or in this case he only needed a couple numbers) and the cabinets magikally appear.
self-stick Velcro spots -- they come in packages of 10 at Home Despot.
dave
fdegrove said:
the Cherry stain gives them the lovely reddish colour -- something that so far has gotten very high SAF (across a sample set of a number of Ss)
BTW i get no credit with how they look, ChrisB is the cabinet maker. I send him drawings (or in this case he only needed a couple numbers) and the cabinets magikally appear.
self-stick Velcro spots -- they come in packages of 10 at Home Despot.
dave
pinkmouse said:but no construction photos, shame...
Any internal drawings so we can see how you configured the line?
ChrisB doesn't have a camera yet... and they would be pretty boring anyway -- it is 5 pieces of wood.
The beauty of the alphaTL is that it is so simple. Throw a few numbers in a spreadsheet (or use the nomographs that will be in the published article -- coming to an audioXpress soon) and out pops a design.
Rick Schultz (exolinear) has done an excellent job exploring quarterwave space and coming up with a set of plug-n-play working parameters for the simplest of tlines. I can't talk about details until the article hits, but the line configuration is the same as the TLb. El Pipe-O and my toobz all have the same topology as an alphaTL -- but aren't dimensioned correctly to be alphaTLs.
dave
Banned
Joined 2002
JasonL said:
They have been in my system since Christmas... and i haven't been tempted to pull the Quad ESLs (you see them just behind one of the TLs) out -- they are next in the queue.
They aren't as transparent thru the mids as my BD-Pipes, but have bass the 4" can't hope to match. They are pleasant to listen too, but i can't give you a critical evaluation since i am currently source deprived ... i'm having to live with my Denon 2500 DVD player until i can resurrect one of the TTs in storage.
Next up in this theme is a set using Vifa P17s & much better tweeters. And the mid enclosures in my 1st TangBand effort (this design is still in flux -- i'm switching to 4" bass drivers from the 3s in the 1st design.
dave
roddyama said:
They use cheap MCM 6" (i have to go look for the number) & a surplus 14mm Delco tweeter.
Wave guide would be a more appropriate term. This is a little trick stumbled on by accident. The system is best described as full-range with a helper tweeter (6-7k up). The conical wave-guide gives a bit better match between the drivers HF and the tweeters LF dispersion characteristic. The loading also gives a bit more LF efficiency on the T. The set-back brings the acoustic centres a bit closer and cosmetically it works -- making what is a rather inexpensive tweeter look better.
dave
mystery stain
As Dave said, "rescued from the scrap pile" cherry veneer factory laid on MDF core. Due to the the different age of material, there was significant variation in the color of the veneer ( although cherry is my current favorite, this oxidization is quite normal). This prompted the dark red stain.
My biggest suprise was how well the exposed edges of the MDF core took the stain. Sanded down to 220 with random orbit, then 2 coats of stain (second one washed with thinners) and 4 spray coats of nitrocellulose lacquer.
The velcro pads work great on smaller sized grilles, and are also available in white. Next pair of boxes with PLAm or post veneer, I'd like to try the concealed magnets.
As Dave said, "rescued from the scrap pile" cherry veneer factory laid on MDF core. Due to the the different age of material, there was significant variation in the color of the veneer ( although cherry is my current favorite, this oxidization is quite normal). This prompted the dark red stain.
My biggest suprise was how well the exposed edges of the MDF core took the stain. Sanded down to 220 with random orbit, then 2 coats of stain (second one washed with thinners) and 4 spray coats of nitrocellulose lacquer.
The velcro pads work great on smaller sized grilles, and are also available in white. Next pair of boxes with PLAm or post veneer, I'd like to try the concealed magnets.
stain
Stain (commercial solvent based wipe-on) applied directly to sanded veneer / MDF core. As cherry can easily go blotchy, I've found the fastest way for an even color is to wipe on 2 thick coats & wash down with lacquer thinner before each dries.
Usually 3 - 4 spray coats of catalyzed nitro cellulose lacquer with a quick 220 - 400g sanding between coats.
Thank heavens I'm not in California.
Stain (commercial solvent based wipe-on) applied directly to sanded veneer / MDF core. As cherry can easily go blotchy, I've found the fastest way for an even color is to wipe on 2 thick coats & wash down with lacquer thinner before each dries.
Usually 3 - 4 spray coats of catalyzed nitro cellulose lacquer with a quick 220 - 400g sanding between coats.
Thank heavens I'm not in California.
Alpha TL missing details
Hi Dave
Finally I could read Rick Schultz's article and was very impressive how fast and easy you can dimension the box and stuffing.
Two points I could not figure out is if is there any rule for woofer placemant from top of box and what is max or min distance of open end to floor. Or this is not a big deal.
Thanks for comments
Hi Dave
Finally I could read Rick Schultz's article and was very impressive how fast and easy you can dimension the box and stuffing.
Two points I could not figure out is if is there any rule for woofer placemant from top of box and what is max or min distance of open end to floor. Or this is not a big deal.
Thanks for comments
Re: Alpha TL missing details
The alpha TL assumes the driver is as close to the closed end as you can get it. The area of the space above the floor should be larger than the opening in the pipe... too high up off the floor and you will probably lose some bass reinforcement. Still i have one in the works that will have the terminus significantly raised above the floor.
dave
JC Fardo said:
The alpha TL assumes the driver is as close to the closed end as you can get it. The area of the space above the floor should be larger than the opening in the pipe... too high up off the floor and you will probably lose some bass reinforcement. Still i have one in the works that will have the terminus significantly raised above the floor.
dave
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