Does anyone have the Bottlehead straight 8 cabinet plans? (I have the crosssover drawings already)
I bought drive units from mcm sooooo long ago...and never got around to building it.
Thanks in advance. The bottlehead site links are broken by the way.
I bought drive units from mcm sooooo long ago...and never got around to building it.
Thanks in advance. The bottlehead site links are broken by the way.
The Wayback machine is your friend: http://web.archive.org/web/20110114033031/http://www.bottlehead.com/straight 8/Straight8.pdf
For any future dishonest types trawling the forums looking for ideas to steal and profit by, please note caveat posted by Doc.B:
For any future dishonest types trawling the forums looking for ideas to steal and profit by, please note caveat posted by Doc.B:
Thanks!
I used the wayback machine in the past...but did not think to use it this time...getting old.
I used the wayback machine in the past...but did not think to use it this time...getting old.
Nice. Don't see too many 1st order XO speaker designs anymore. Do these drivers naturally have a controlled flat response - as those look like aluminum cone mid bass drivers that may have a peak up high that will leak through a first order.
I believe Bottlehead coated the cones with something like damar varnish to kill some peak.
You might ask about that on the Bottlehead forum.
You might ask about that on the Bottlehead forum.
I did notice the plans said "treated" drivers. I wonder if these are the MCM 55-1870's?
A real good 5.25in driver that has no nasty peak is the AC130-F1. It's substantially more expensive though but I have crossed it with first order with good success. 8 of tbem per side would break the bank though.
A real good 5.25in driver that has no nasty peak is the AC130-F1. It's substantially more expensive though but I have crossed it with first order with good success. 8 of tbem per side would break the bank though.
To a point. Since you're interested:
-The Straight 8 crossover went through a few variations & ended up with an asymmetric 3rd order (3rd order electrical + Zobel on the midbass array, 2nd order electrical + a parallel & a series notch on the tweeter). Don't ask me what the acoustic slopes were -I didn't back-engineer it, nor would I think it fair to do so. That would be tricky in any case because of the next point.
-The Straight 8 was the last in a series of designs that they'd played with for the best part of a decade. The 1870 was used, with some damar coating + a couple of other tweaks IIRC, presumably to mechanically damp out a bell mode. However: as I understand it, at some point, the OEM making the 1870 changed the driver design without bothering to tell anyone. Going by fallible memory, the curvilinear profile went west, along with a couple of other things. Basically, it wasn't the same driver, and it was no longer usable. So the Straight 8 was retired, and I think they informally point people toward Clark Blumenstein's speakers now as he's nearby and also offers nice bamboo ply etc. plinths for Bottlehead kits.
-The Straight 8 crossover went through a few variations & ended up with an asymmetric 3rd order (3rd order electrical + Zobel on the midbass array, 2nd order electrical + a parallel & a series notch on the tweeter). Don't ask me what the acoustic slopes were -I didn't back-engineer it, nor would I think it fair to do so. That would be tricky in any case because of the next point.
-The Straight 8 was the last in a series of designs that they'd played with for the best part of a decade. The 1870 was used, with some damar coating + a couple of other tweaks IIRC, presumably to mechanically damp out a bell mode. However: as I understand it, at some point, the OEM making the 1870 changed the driver design without bothering to tell anyone. Going by fallible memory, the curvilinear profile went west, along with a couple of other things. Basically, it wasn't the same driver, and it was no longer usable. So the Straight 8 was retired, and I think they informally point people toward Clark Blumenstein's speakers now as he's nearby and also offers nice bamboo ply etc. plinths for Bottlehead kits.
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I'm planning on using my Beyma CP 21F's in lieu of the Selenium ST 324 that bottlehead used towards the end of the s8's life.
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