ajsons
-
Posts
543 -
Joined
-
Last visited
Content Type
Forums
Events
Gallery
Posts posted by ajsons
-
-
Sorry, double post and the .bmp picture wouldn't load.
-
Chris,
I can't find the specs on the T-30. Do you have one?
Here's another picture of cobreflexes. Personally, I think they look good and rightfully belong in the Classic.
-
TNX for the post. Yes that's an H600, beautiful horn. I plan on using that for a center channel speaker.
And you're right, the cobreflex III is fiberglass, with a bigger throat.
-
"If you want to start a Classic builder's thread I would be an active participant and contribute what little knowledge I have to the common good. I am a fairly decent amateur cabinet maker. Perhaps that would help."
What I really need is a fairly decent cabinet maker I can team up with to build folded horns! I wish I live in Texas, right now. Or maybe in Washington state. BTW, my beautiful sister-in-law lives in Whidbey.
"I am also interested in WAF, but more for myself. That extends to wondering how you might be able to construct 30"x40" speaker grilles that can handle being repetitively installed and removed, yet still be fairly acoustically transparent. I don't think the orginal designs would work. they look awfully bulky and have those cross-basrs, but they may not have that much influence on large bass horns and stand-alone mid- and high- horns that are suspended in the bass mouth. Again, an area I have no experience in."
The Classic's speaker grille construction really impresses me, it is well-made, very good joinery and can handle repetitive on-offs . Joinery on all exterior pieces is pretty good. It is in the inside pieces where craftsmanship is sloppy. I had to take off the grill this weekend and drew it in AutoCAD. The grille cloth looks acoustically fine, but man, I hate that color. Did the drawing of the base, too, but that was the wimpiest part of the enclosure. I took that off and when the weather gets better, I'll use 2 x 4's . Right now, my Classic has no base.
"Another thought is the "shelf" created by one side of the doghouse at the bottom when the Classic is in the vertical position. Strictly for appearance sake, what would happen acoustically if it were enclosed?"
I'm not sure which area you're referring to, but if it is the bottom unused section around the throat pieces, that's the one I was referring to that needs to be enclosed and sealed with an additional piece in front, holes made through the motorboard to make it a part of the rear chamber to gain cubic inches a necessity to my EV driver, or any driver that needs it.
"The last thought I had was if the Classics were going to be redrawn, are they currently optimized. I may have missed something, but D-Man's comments lead me to believe he thinks they're fine the way they are. Also, as Q-Man suggested, you can start with the drivers originally specified and then go from there."
I am sticking to the original dimensions of the Classic with the exception of the reflectors angle at the throat, first bend and the large one.
The last change I made at the throat Dana said is fine. At the first bend I saw it as 42+degrees, he saw it at 47+, but we're using opposite references. It is the same thing. It equals 90 degrees. The large reflector has to be adjusted by a couple of degrees. These were discussed through emails and were not posted.
"I suspect my 50'ish ears will probably be happy with the originals."
Most likely you will. Out of the three changes though, I think the reflector at the first bend is a necessity. And if you don't want it you can take it off. The reflector in my Classic is screwed with no glue.
I like the C15W. I was lucky to have EV spares to compare woofers performance. If I were you, I'll use the components that you have now, then try different drivers as you get familiarized with the sound. I have 5 pairs of midrange drivers, but prefer the EV 1824M.
BTW, I don't have an HF-206, and have no intention of getting one, unless the price is right. (Yes, I'm el-cheapo). I need to draw it in AutoCAD. Can you take dimensions for me, if you don't mind? I'll send you some pictures via e-mail, and you can write down the dimensions on them, or whatever works.
Armando
-
The University T-30 mid driver
-
Chris (Quistive),
We're still with you. It might have appeared that we were going in unfamiliar territories, but we're still with you.
Classic or La Scala?
Or maybe both in a single enclosure..
-
I've been looking for info on the Gately Super horn. TNX for the post. I've never heard of the Rice's.
Do you have anything on the Drisko horn?
-
-
I'm glad you clarified the single path with a divider issue. I can use all those info.
-
Cobreflex specs, page 2
-
At first glance, I like it.
DM
(Whew! I was worried that you won't!)
Maybe one of my ideas will get me a patent, too.
Hey what's the word on yours?
-
Specs for the Cobreflex.
-
The Cobreflex is really a hi-fi speaker, not PA, but found its way in that arena, perhaps because of its utilitarian look. It sounded very good to me with the EV 1824M midrange and a little harsh with the T-30 driver it came with.
Here's mine, one disassembled, ready for final sandblasting.
-
Is it a bad idea?
-
Woffer access will be to the rear, (I have not shown that), unused space around the throat area will be sealed and opened to become a part of the woofer rear chamber. Dimensions, especially the path expansion will be kept identical to the Classic, what I lose in depth I can regain in height, if there's any.
-
I do not particularily see a reason for bifurcating the throat of the Classic. What are you seeking to do? Does this have anything to do with the horizontal brace that we talked about?
DM
No, I have something else in mind. I was trying to see the possibilties of reducing the size of the Classic, especially the depth. I can live with the 30 inch width, and 40 or higher height, but 24 inches sticking out into my den takes up a lot of space. There is nothing you can really do to reduce that if the initial path is shooting to the rear of the enclosure but if I shoot it to the side, like a Belle then I can reduce the depth.
See the attached picture. Imagine the Classic with La Scala doghouse on its back tilted 14+ degrees, with the rest of the path of the Classic. The drawing is on its rough stage, I have not shown the other pieces of the bifurcated section. I think it will work. The name BTW, brings back memories of my college years.
-
The black version. I think University started making this when they moved to a different plant.
Here's a description from a 1961 ALLIED RADIO CATALOG:MODEL C-15W 15" WOOFER. TOP-PERFORMING WOOFER FEATURING SPECIAL-DESIGN
DUAL VOICE COIL--TWO ELECTRICALLY INDEPENDENT VOICE COILS ON A SINGLE WOOFER.
DUAL-SPIDER PISTON AND 6-LB. MAGNET ASSURE CLEAN RESPONSE FROM BELOW 25
TO 1500 CPS. CAPACITY, 50 WATTS. DUAL IMPEDANCE VOICE COIL ASSEMBLY
PERMITS USE IN ANY SYSTEM OF 4-20 OHMS. DEPTH 10 1/2".The depth applies to the gold and green version above. The black one appears shorter.
-
Its a dual impedance woofer, it shows up on ebay every now and then, so paying $200 for one (and it had happened on more than one occassion) in excellent condition is insane. I waited and bidded when nobody was paying attention, got three for about $60 each. They are all in excellent condition.
-
The first Classic thread is now 6 pages long, so I'm starting Part Two and it will be mostly about drivers specs, construction details, and improvements.
I will post cad drawings of added parts (reflectors, braces, etc) or modified pieces later on.
Inputs (photos, comments, etc.) are definitely encouraged.
The specs for the C15W woofer are hard to find, but now it is on this forum. I found this from an old issue of Speaker Builder. The bolt pattern for this woofer matches most of todays 15" woofers, so substitution is not a problem.
-
We are getting into the idea that "bass notes" are not particularily directional, aren't we? It depends on the circumstances.
DM
No, I was still in bifurcation versus single path thoughts.
For a while there, after reading the University ad I posted earlier, I was asking myself what kind of tradeoffs are there when you bifurcate the path? Do you mess up the wavefront? If you do, how do you get it back together? Shall I stay away from bifurcating the horn path?
Now, I understand. It seems like the more I learn about horn design, the more I find out that there is very little I know.
-
Al,
You need to take a lot of pictures during construction, and post them on the forum. Good luck with your Classics.
If there's something I can help you with, like details not obvious from the plans, dimensions for the front grill cover, etc. let me know.
I'll start a new thread for the driver specs, and other construction details plus cad drawings of mods, additional parts, etc. You are welcome to input your drawings.
Armando
-
You're welcome. I will re-post the specs in another Classic thread, along with the other drivers specs.
-
There are some very sound ideas behind bifurcation, though. The first being that the horn folds have to occur BEFORE the horn channels cross-section reaches 0.6 of a wavelength to avoid 180 degree reflections, and of course, smaller channel dimensions means a longer distance before this comes into play.
The second is that the respective channels are small(er) and that makes for a reduced footprint size and a throat configuration of narrow dimensions.
The third is that folds themselves work best when the dimensions across the fold is small.
All of the above reasons are very sound physical solutions and allow for a relatively long horn length in a relatively small space.
DM
Sound solutions that are very sound, indeed! Bifurcation, inside the horn based on the above, is ok then.
The La Scala, like the Klipschorn, is bifurcated, with a single mouth. The Klipschorn has two separate smaller mouths, separated by the enclosure. What happens to the wavefront here at exit time?
-
Where they could outperform a Khorn is in the apparent speed of transients (drums, mid-bass, vocals) with the attendant "punch" and convincing authority of an A7. I would expect the efficiency to be on par with the Khorn, but that depends on the driver employed. Perhaps it was performance-to-size ratio (and visa-versa) for why they went extinct in the first place. The point being, that if you are willing to sacrifice some floorspace, how about an extra octave of LF to go with it (i.e., a Khorn)?
However, I have no doubt that they could be very delicious to listen to if one can live with their size and crosses them over properly.
DM
Tasty!
University Classic Part 2 Driver Specs & Mods
in Technical/Restorations
Posted
Chris,
I can't find the specs on the T-30. Do you have them?