Mark Audio CHR-70 Application Thread

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designing an evolving range of loudspeakers that actually sound good (and getting someone else to build them) - priceless

Someone build it and report back. Based on the microTowers built already should work fine

dave

Yes sir....right away sir :p

Gonna be a long week. I have like 4 other things I need to build. But now those CHR's you modified for me will finally have a home.
 
the saga continues...

Chris, er, I thought that's where the art is, transferring from "design" to "reality" while ensuring great sound;)

Dave, I figured as much. So a first order @500-600Hz?

As far as building and reporting back, it might be useful to have a list of speakers (type and information if appropriate and not a commercial design) actually built,. Perhaps this could be something done in a "closed" thread made up of stickied post administered by you only. That way there could be some organization on diyaud or on your website, Dave?

It is almost as though a complete "family tree" could be of the designs could be done graphically. I guess I'm dreamin' a little :)
 
Chris, er, I thought that's where the art is, transferring from "design" to "reality" while ensuring great sound;)

reference clearly obtuse enough for plausible deniability (PM for elaboration if desired)

It is almost as though a complete "family tree" could be of the designs could be done graphically. I guess I'm dreamin' a little :)
I suspect more of a Gordian knot of inspiration & derivation

many paths, one goal?
 
frugal-phile™
Joined 2001
Paid Member
It is almost as though a complete "family tree" could be of the designs could be done graphically. I guess I'm dreamin' a little :)

An out-of-date family tree for the Spawns exist. New boxes have come faster than the little boxes in the tree could reproduce. It is a good idea. It is behind this quarters GST, revised Mar-Kel70, Avebury & Silbury thou.

dave
 
frugal-phile™
Joined 2001
Paid Member
Dave, on that design, is that a 1" by 3/4" piece in the port? And length is determined by the board on bottom that it rests on? (6 1/8")

The port spacer is 3/4" high, 1" wide and extends the full depth of the port (turning the slot into 2 rectangular ports). It could extend all the way to the back of the box to add some more bracing to the top of the box. A stethescope on the back panel, when built, will tell us if there will be any benefit from a holey brace in the last half of the line.

dave
 
Skinny folded halfTower with front exiting terminus.

folded halfTower 0v8 map

Someone build it and report back. Based on the microTowers built already should work fine

Would need to be reworked for the EL70

dave

Dave,

You're killing me with the 5/8" wood thickness. I think I got through making 90% of the entire cut sheet before I realized you weren't using 3/4" lol :p
 
A very complete set of plans will be available for a small cost once the beta testors have all reported back.

We have been planning on selling comprehensive plans (similar to what Bob Brines does), these are 1st because it is part of a commercial licencing agreement with a manufacturer in Denmark that is building the Alpair7 version as part of his commercial line.

The boxes for CHR70 and A7 are the same except for the details required of the different dimension drivers and slightly different porting. The plans will include both.

dave

Any news on when these plans will be available? I would certainly be interested in buying a set of plans.
 
Almost didn't have enough wood to finish them. Here they are all sanded after some wood filler and roundovers. Paint will come soon.

I was actually able to get the cutout for the drivers so exact that it could, in theory, work as a press fit. I wont use it that way but its nice to know that they'll be getting extra support on the flange rather than just the four small screws.

DSC02160.jpg
 
OK, a beta-testers note that I forgot earlier:

Note that the 2010 CHR-70 comes with a 2mm gasket, which really doesn't compress very much, so it needs to be accounted for when cutting the rebates. My drivers were perfectly flush in their rebates without the gasket, but are rather decidedly not when installed.
 
OK, a beta-testers note that I forgot earlier:

Note that the 2010 CHR-70 comes with a 2mm gasket, which really doesn't compress very much, so it needs to be accounted for when cutting the rebates. My drivers were perfectly flush in their rebates without the gasket, but are rather decidedly not when installed.

Excellent note. Thanks for letting us know!
 
frugal-phile™
Joined 2001
Paid Member
OK, a beta-testers note that I forgot earlier:

Note that the 2010 CHR-70 comes with a 2mm gasket, which really doesn't compress very much, so it needs to be accounted for when cutting the rebates. My drivers were perfectly flush in their rebates without the gasket, but are rather decidedly not when installed.

A good note. I do get the gaskets to compress as far as 1.3mm. I have just gotten the 1st of my Mk2 CHR (and their gaskets). I didn't much use the older ones, but these look to be an improvement.

dave
 
A good note. I do get the gaskets to compress as far as 1.3mm. I have just gotten the 1st of my Mk2 CHR (and their gaskets). I didn't much use the older ones, but these look to be an improvement.

dave

I've yet to try any of the Mk2. I'll be putting the enabled mk1 drivers in these new cabinets. I test fitted them earlier before I put the primer on.:p
 
I've yet to try any of the Mk2. I'll be putting the enabled mk1 drivers in these new cabinets. I test fitted them earlier before I put the primer on.:p

hey man... instead of primer.. go buy some Slicksand.. it's polyester based and is less prone to shrinking and cracking if mixed right.. this is very important when covering seams..

mix it 2oz per ever 1cc of catalyst and your golden.. and it sands like a dream..
 
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