John Warren Posted April 18, 2004 Share Posted April 18, 2004 Altec Grey? I was asked by a fellow here in the Boston area to make a pair of JBL 2404H add-ons for his Altec A-7s. They were in the battleship grey color scheme. It took a few mixs but were able to match the color very closely. I liked the color so much I hung my own stands in the booth and gave them a spray (they got three coats with sanding between). Quote Link to comment Share on other sites More sharing options...
IndyKlipschFan Posted April 18, 2004 Share Posted April 18, 2004 THOSE are awesome!! Quote Link to comment Share on other sites More sharing options...
hoggy Posted April 19, 2004 Share Posted April 19, 2004 Looks very nice. hoggy Quote Link to comment Share on other sites More sharing options...
John Warren Posted April 19, 2004 Author Share Posted April 19, 2004 They "do" look cool don't they. I learned, quite unintentionally, that it is not easy to photograph the color grey without it looking like blue or purple. The color is best rendered under halogen lamps. If you can believe it, I used two 100W halogen spots to get these pictures. Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted April 19, 2004 Share Posted April 19, 2004 John, You know me, I'm interested in tyhe network! That tweeter is constant directivity, doesn't it require and equalizer? Doesn't that cut the sensitivity down too much to match and A7? I did that with a Beyma CP09 CD tweeter on my "Heresy on steroids" project and wound up with only 90 dB sensitivity. That was right for a direct radiator though. The A7 is much higher. BTW: I like the grey too. To my eye, that shade of grey tricks my eyes into seeing a pale blue! Al K. Quote Link to comment Share on other sites More sharing options...
Q-Man Posted April 19, 2004 Share Posted April 19, 2004 If were doing the Altec grey thing, they also had their horns painted grey. What do you guys think? Should the tweeter lens also be painted grey? Quote Link to comment Share on other sites More sharing options...
John Warren Posted April 19, 2004 Author Share Posted April 19, 2004 ---------------- On 4/19/2004 7:48:32 AM Al Klappenberger wrote: John, You know me, I'm interested in tyhe network! That tweeter is constant directivity, doesn't it require and equalizer? The on-axis, 1m, -3dB frequency is 19kHz. The 50° off-axis, 1m, -6dB frequency is 20kHz. Doesn't that cut the sensitivity down too much to match and A7? The minimum on axis SPL between 3.2-20kHz is rated at 105dB/W/m with -3dB frequency at 19kHz. The on-axis response dos not exhibit the roll-off typical of CD horns. The on-axis, -10dB frequency is 21.5 kHz. Having said that, the same motor structure is used in the JBL conical tweeter and that hits 112dB/W/m so some efficiency is disposed of "selectively". I did that with a Beyma CP09 CD tweeter on my "Heresy on steroids" project and wound up with only 90 dB sensitivity. The -09 has issues above 15kHz. That was right for a direct radiator though. The A7 is much higher. BTW: I like the grey too. To my eye, that shade of grey tricks my eyes into seeing a pale blue! The A7 has an odd color. I think Altec used primer as a finished coat. Al K. ---------------- Quote Link to comment Share on other sites More sharing options...
TBrennan Posted April 19, 2004 Share Posted April 19, 2004 Qman---As I recall Altec painted the multi-cells that came with A5s and larger systems black and then later on gray. I think the horns used with A7s and A7-500s were always black, except for the "greenies". Quote Link to comment Share on other sites More sharing options...
hwatkins Posted April 19, 2004 Share Posted April 19, 2004 Very cool John. I will PM - Baby Cheeks are now part of my new project and I want some of your thoughts. Quote Link to comment Share on other sites More sharing options...
Q-Man Posted April 19, 2004 Share Posted April 19, 2004 Tom, Your right. I'm just used to my 805-B's and 311-90's. Quote Link to comment Share on other sites More sharing options...
John Warren Posted April 19, 2004 Author Share Posted April 19, 2004 ---------------- On 4/19/2004 10:39:10 AM Q-Man wrote: If were doing the Altec grey thing, they also had their horns painted grey. What do you guys think? Should the tweeter lens also be painted grey? ---------------- Why stop there, we could spray the whole thing, caps, terminal block, wires, etc. Then it would be an "object-of-art". Quote Link to comment Share on other sites More sharing options...
Q-Man Posted April 19, 2004 Share Posted April 19, 2004 Smart a**, but maybe I deserved that. Then it would like a blob of paint. Contrast is a good thing. Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted April 19, 2004 Share Posted April 19, 2004 John, A friend email me the specks on the tweeter. I see JBL has solved that need for an eq in that model. As to the Beyma CP09, Mine went nicely to nearly 21K. I'm not sure Beyma even makes that model any more though. No matter, I only used the CP09 becasue I got two of them real cheap on eBay! Al K. Quote Link to comment Share on other sites More sharing options...
sunnysal Posted April 20, 2004 Share Posted April 20, 2004 nice work john! how did you come up with the design for the x-over? or is it just "improved stock"? warm regards, tony Quote Link to comment Share on other sites More sharing options...
ZAKO Posted April 20, 2004 Share Posted April 20, 2004 John....The 2404,s should be painted JBL BLUE. Quote Link to comment Share on other sites More sharing options...
John Warren Posted April 20, 2004 Author Share Posted April 20, 2004 ---------------- On 4/20/2004 4:05:15 AM sunnysal wrote: nice work john! how did you come up with the design for the x-over? or is it just "improved stock"? warm regards, tony---------------- Tony- The networks are my own design and consist of a single LCR filter and a 3rd, 4.5kHz Butterworth filter. The BW terminates into a 7 Ohm load between 3-6kHz thanks to the LCR conjugate. The design is similar to the one I made for Gary's filters (Q-man). In his however, I went to 6kHz. Even with the attenuation provided by the LCR filter, the 2404H needs additional attenuation and I use a 1.5dB Lpad for that. I'm putting a small website together that shows the schematic, parts list and how to make the stand. When it's done I'll post it. Maron- JBL Blue did come to mind. Didn't JBL also make a very light grey? I think walnut and cherry finished are overated. Loudspeakers are engineered systems, not furniture. Quote Link to comment Share on other sites More sharing options...
ZAKO Posted April 21, 2004 Share Posted April 21, 2004 JOHN......You think like an engineer. All speakers fit in furniture cabinets. Yes the early JBL,s were light grey. Then dark grey then blue then black.. some special order units in orange And for Bob Heil, Purple. Quote Link to comment Share on other sites More sharing options...
Q-Man Posted April 21, 2004 Share Posted April 21, 2004 Finally someone who thinks like me. I personally could care less what my speakers look like. That's why some of my prototypes are still raw plywood. Quote Link to comment Share on other sites More sharing options...
sunnysal Posted April 21, 2004 Share Posted April 21, 2004 thanks john, I look forward to seeing the web site when you have it up. bet it will sound marvelous! tony Quote Link to comment Share on other sites More sharing options...
John Warren Posted May 1, 2004 Author Share Posted May 1, 2004 These were done using textured black spray. The surface ends up looking similar to crinkle. I managed to achieve glass smooth surfaces on the external faces using a filler compound, sanding, priming, sanding, priming, etc. technique until the final color was laid down. Quote Link to comment Share on other sites More sharing options...
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