I awoke at 3 am with an idea. Started the project at around 9am, once I had the house to myself.
I'll let the photos do the talking.
I'll let the photos do the talking.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
That is not a table, it is a vintage Clairtone console, which houses two (original) 12" paper plus AlNiCo woofers which are doing the bass duty in this system via miniDSP (Bessel at 200Hz). The punch is insane.
The center lid opens, and inside I have installed a Technics SL-10, a tube amp, and there is room for album storage.
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High Frequencies peaks
Cogitech,
I heard that the Alpair 10p(I own CHR-70) sounds quite good. However after visiting Bob Brine's website I noticed that this model exhibits high frequencies peaks above 4-5kHz, does your unit exhibits this behavior as well if so did you use and filter(s) to tame them. If not do you find them annoying. A reply is welcomed.
Bob's reference
B10-A10
Cogitech,
I heard that the Alpair 10p(I own CHR-70) sounds quite good. However after visiting Bob Brine's website I noticed that this model exhibits high frequencies peaks above 4-5kHz, does your unit exhibits this behavior as well if so did you use and filter(s) to tame them. If not do you find them annoying. A reply is welcomed.
Bob's reference
B10-A10
I have certainly not heard anything that sounds the way that response graph looks. In fact, I have a +5dB high shelf starting at 5kHz to coax a bit more "air" out of mine.
I do plan to measure mine at some point, though. Just have to buy a proper mic.
I did some more listening last night and I am really enjoying this experiment. This is my first experience with open baffles so I have no frame of reference, but this quasi U-frame configuration seems to be working in my space. If I put my ear behind the baffle, right near the two drivers, there is definitely some resonance in the curved pocket that I might be wise to eliminate. A few minutes with the jigsaw will confirm that theory.
The girls in the house really like the look of them. WAF is definite higher than the original Pensil. I should also note that I would never have done this to a "finished" pair of boxes, and I would never try this if not for supporting bass drivers and miniDSP. Mostly I was curious how the two pairs of Alpairs would sound in the Castle configuration, and I have been wanting to try OB for a long time.
The girls in the house really like the look of them. WAF is definite higher than the original Pensil. I should also note that I would never have done this to a "finished" pair of boxes, and I would never try this if not for supporting bass drivers and miniDSP. Mostly I was curious how the two pairs of Alpairs would sound in the Castle configuration, and I have been wanting to try OB for a long time.
Nothing wrong with the original enclosures other than they were simply not right for me and my rather large room. They were originally built for Alpair 10.2 but I was never truly satisfied with the bass. If I EQed enough for my bass needs, I was regularly running at or near the recommended excursion limits of the drivers, and I don't like to treat them that way. I knew the Pensils were simply not for me, so they never got sanded and finished. I popped the A10Ps in them for break-in purposes and they functioned fine for that, with half-baked bass support.
Recently I got the miniDSP and dialed in a crossover and EQ correction that works really well in my room, with the Clairtone woofers taking everything from 200Hz down. Relieving the A10Ps from bass duty was like a revelation to me; I am a true believer in intermodulation distortion now. When it is absent, it is obvious.
Giving all the bass to the 12" Clairtones also rendered the monolithic Pensil cabinets completely unnecessary. But, what to do with them? The answer was "Open Castle". My love of the Castle configuration started with my EL70 microTowers and I missed that dimension of sound with the Pensils. The opportunity to try OB was simply the icing on the cake.
A10P + A10.2 paralleled for a 4 ohm "Castle", with no bass duty, can handle a ridiculous amount of power without any sign of distortion at all. Talk about headroom.
My plan is to open up the two Clairtone woofer enclosures and turn them into U-frame OBs, then measure their response and tweak accordingly. The "Open Castle" will likely get hacked even more (already have plans to flush-mount the top drivers and cut a large hole out of the upper portion of the sides to reduce or eliminate the "boxy" resonance mention earlier), and at some point I may re-build them from scratch.
My original plan was to build the "CogiCastles" (A10P + A10.2 in Castle MLTL) which I commissioned Scott and Dave to design for me. They may still get made some day, but something tells me that once again I might not be satisfied with the bass...
If I am going to let the Clairtone cabinet have all the bass, then why have the Alpairs in cabinets at all?
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Great idea on repurposing a cabinet. I am glad you found that using the miniDSP and a helper woofer a la FAST works so well. I felt the same way when I went down this path. You can get a small fullrange driver to some pretty crazy loud levels and keep distortion way low because the cone is hardly moving 200 Hz and above. The top firing driver must give you some pretty nice spaciousness. Many OB's from the 50's had an up firing tweeter on a small shelf for same reason.
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