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Old 27th June 2014, 03:00 AM   #1
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Default Alpair 7P developments

Hi Guys,
Briefly bringing you up to date, we are now in the final pre-production stages of this driver. Likely we will begin the first production batch later this month.

This driver has been a very time absorbing project, but one that I think will deliver rewards. I'll explain in more detail over the coming weeks, but for now here's 2 pics of interest.

There's a pic showing our early experimentation on the pre-production cones. You can see Evan applying a mixed glass fibre (GF) bonding material to sections of a cone. Once applied, the cones are accurately weighed to achieve a mean mass variance tolerance of +/- 2.5%, samples falling outside the range are discarded. We sometimes use these types of mass application to measure the effects of altering the cone's rigidity profile. Although this time, we may convert this process for use on the 7p's production as its proved quite interesting in respect of response flattening.

The other pic is of the latest pre-production unit. I think you'll find it looks very attractive.

Regarding performance, the 7P is expected to deliver an F zero around 70Hz with an operating range to +25kHz. The overall response will be relatively flat with a lift in upper band starting higher than its metal counterpart at about 19kHz. Total Q is projected to be around 0.48 with an estimated MMS of 3g. SPL is projected to be around 86.6 to 87dB.

The F zero of this driver is expected to be within 1.5dB of the Alpair 12PW woofer, thus creating an interesting combination. Equally, the 7P will be happy to operate as a single-point-source unit for purist audio application.

More later.

Thanks
Mark.
Attached Images
File Type: jpg Alp7P.jpg (96.8 KB, 895 views)
File Type: jpg Alp7P-cone-exp.jpg (62.5 KB, 876 views)

Last edited by markaudio; 27th June 2014 at 03:11 AM.
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Old 27th June 2014, 05:02 AM   #2
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I think you'll find it looks very attractive.
They are lovely. Thanks for the update Mark.

jeff
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Old 27th June 2014, 05:31 PM   #3
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Looking forward to updates.
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Old 27th June 2014, 08:13 PM   #4
chrisb is offline chrisb  Canada
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Interesting spoked arrangement of adhesive on rear side of cone - is that something new to both the paper and metals?

Will this be offered with detached bezel?
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Old 28th June 2014, 12:00 AM   #5
von Ah is offline von Ah  United States
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Very. Exciting.
Great work, and thanks, Mark!
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Old 28th June 2014, 06:08 AM   #6
EUVL is offline EUVL  Europe
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I hope you will be applying the GF bonding material by a machine in volume production.




Patrick
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Old 28th June 2014, 06:53 AM   #7
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I hope you will be applying the GF bonding material by a machine in volume production.




Patrick
We're looking at modifying of our machines. But the cost will be some US$3000. Good if we are making volumes in excess of 1000 units per time, but unlikely viable at such an early stage. So the first batch will likely use a mixed injector guided by a template. The mixed bond volumes are accurately controlled while requiring a skilled technician to guide the injection head over the template. A job for Allan or Evan me thinks.

Which ever method we use, cones will be checked for mean mass as per our testing of components.

Thanks

Mark
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Old 28th June 2014, 07:29 AM   #8
EUVL is offline EUVL  Europe
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Talk to Mark Lai.
He has years of professional experience in automated epoxy dispensing (in 3D).


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Old 28th June 2014, 10:11 AM   #9
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Talk to Mark Lai.
He has years of professional experience in automated epoxy dispensing (in 3D).

Patrick
Hi Patrick,
I forgot to ask, how's life in EU? All well I hope. I should catch up with Mark L sometime, not sure what he's doing these days. We've just completed CHN's, Alp7P's and 12PW's almost done, Alpair 8 at next stage (can't leave this concept alone). Plus we'll move to larger workshops sometime in August.

Mark.
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Old 28th June 2014, 12:53 PM   #10
EUVL is offline EUVL  Europe
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I was in Hong Kong for 5 weeks in May. Family emergency.
Just got back and try to get my own life back on track ......
Also moved home earlier in the year, and still not fully unpacked yet.

Mark is very busy, but you can ask him about dispensing machine.


Cheers,
Patrick
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