CHR-70 back mount

[chrisb]

Adding the front cover does increase the recess depth. For some box makers, this is a build challenge, so the choice is their's to decline the use of the covers. Please use the covers where possible, subject to your front baffle thickness. Ideally, net baffle thickness (side wall facing the rear of cone) should not exceed 10-mm and should chamfered off, or angled away from the cone.

Thanks
Mark.

I personally prefer not to use the extra ring, in which case the 8.5mm thickness of mounting flange leaves a nice 9.5mm of core when using 18mm plywood. To ensure adequate core for mounting screws, it doesn't hurt to scallop the chamfer around the 4 basket legs, leaving nice pads as shown with earlier A7 G2

 

[markaudio]

I personally prefer not to use the extra ring, in which case the 8.5mm thickness of mounting flange leaves a nice 9.5mm of core when using 18mm plywood. To ensure adequate core for mounting screws, it doesn't hurt to scallop the chamfer around the 4 basket legs, leaving nice pads as shown with earlier A7 G2

OK, I loaded this photo twice, and it still flipped upside down - whatever

Hi Chris, Guys
Chris's mounting work looks very nice. Given the scalloping leaves the full depth of the ply for the screws, it could likely take the the front cover.

Somewhere on the forum, there's several posts referring to tests from a certain German magazine where Alpair driver performance was likely compromised by a baffle that was possibly too thick and un-chamfered. We've also encountered this issue during anechoic tests on early design suspended baffles.

I'm being clear on this point: Keeping the rear recess depth to a minimum will reduce the risk of the driver's back-wave from being reflected onto the back of the cone/power-train. It can be a critical issue on the Alpair series drivers.

Bear in mind I've spent countless hours on the Alpair series, no less so on this latest Alpair 7. Its designed to give the experienced Diyers (audio-holics) and other brave souls every possible performance edge that I can dream up.

In the end, its Diyer's choice as to how to deploy the latest Alpair 7 (and other Markaudio drivers). There's several choices between cover and rear magnet. For ultimate performance, use the cover, keep the rear magnet cover attached to the driver and fully recess with angles/chamfers.

Thanks
Mark.

 

[Westy37]

Thanks for the reply Mark, covered everything nicely.

 

[chrisb]

thanks to moderators for tidying up the photo