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Old 23rd August 2011, 07:57 AM   #1
djanci is offline djanci  Croatia
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Default Clamping driver from the back?

I wonder if CHR-70 Mk2 frame could hold that type of mounting or do I risk damage of driver that way? Of course, if it's not over tighten.

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Old 23rd August 2011, 08:21 AM   #2
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Quote:
Originally Posted by djanci View Post
I wonder if CHR-70 Mk2 frame could hold that type of mounting or do I risk damage of driver that way? Of course, if it's not over tighten.

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Hi Djanci, Guys,
Please DON'T attempt any direct clamping, or any arrangement that applies significant positive/negative pressure to the rear of the driver, of the type illustrated in post No.1.

Markaudio driver's aren't designed to operate with any pressure applied to the rear of the driver. Engaging in this practice could result is stressing the frame, affecting the alignment of the driver's power-train. If this happens, the driver won't perform properly and in severe cases, cause coil rub, effectively killing the driver.

Thanks
Mark.
 
Old 23rd August 2011, 09:18 AM   #3
djanci is offline djanci  Croatia
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Thanks Mark. I thought so but your confirmation means a lot. The problem is that your frame is somewhat elastic and in combination with only 4 screws is a problem because EVA ring elastic force easily bend frame between two screws. Will filling holes in frame (green line) with epoxy resin or even carbon fibre reinforced epoxy resin make any difference?
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Old 23rd August 2011, 10:19 AM   #4
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Quote:
Originally Posted by djanci View Post
Thanks Mark. I thought so but your confirmation means a lot. The problem is that your frame is somewhat elastic and in combination with only 4 screws is a problem because EVA ring elastic force easily bend frame between two screws. Will filling holes in frame (green line) with epoxy resin or even carbon fibre reinforced epoxy resin make any difference?
Hi D,
If you're bending the frame in-between its screw locations, your over-tightening the driver into the baffle. Follow these tips on installing Markaudio drivers (or other polymer and pressed steel framed drivers).

1- Make sure the driver to baffle mating surface is flat. When fitting the driver into a recess, make sure the fit is easy, not tight.

2 - If using the Hex screws we supply, make 2.1-mm pilot holes to accommodate the body of the screw.

3 - Use our EVA gasket (CHR-70, CHP-70 and CHBW-70 models)

4 - Gently, evenly and gradually screw the driver down onto the baffle. You'll feel the screws go tights as the driver positions on the baffle.

Don't over-tighten and don't use a powered driver. All you need is a small sized Allen (Hex) key - see pic. Position yourself at the side of front baffle, eye-ball the flat of driver frame and the flat of the baffle. Adjust the tension of the screws to get the frame level even.

I've been practicing making mini-video's so hope to make an "installation" vid in September.

Cheers
Mark.
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Last edited by markaudio; 23rd August 2011 at 03:14 PM.
 
Old 23rd August 2011, 12:39 PM   #5
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Hi D,
I've deleted you last post as your assertion on the pressure required to mount drivers into baffles is in-correct.

I'm becoming more strict on posts where members make assumptions or assert ideas that are in-correct, as they may mis-lead other Diyers. My audio driver design and manufacturing experience (just built our 100,000th driver) is comprehensive.

Let me be clear: Don't tighten a driver down to the point where the frame distorts. The frames on Markaudio drivers have a resonance damping factor built into their design. They do NOT work properly if heavily tightened on the baffle. The EVA gasket is at a thickness where it will create a reliable seal without the need for heavy compression.

For those guys using ply-wood or solid wood where the contact surface may have minor variations, add a thin beed of silicone sealer under the EVA gasket. This should fill any minor imperfections in the wood surface.

I've closed this thread to keep its information and advice easy to follow on these few posts.

Thanks
Mark.

Last edited by markaudio; 23rd August 2011 at 01:40 PM.
 

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