Driver Hole Chamfer and Alpair 7

[pizzachef]

Any unique recommendations for the Alpair 7 driver hole chamfer. Typically I cut the back of the hole at a 45 degree angle using a router.

[markaudio]

Originally Posted by pizzachef

Any unique recommendations for the Alpair 7 driver hole chamfer. Typically I cut the back of the hole at a 45 degree angle using a router.

Hi Pizzachef,
Yes to 45 degrees. This is a good way to minimise any reflections coming from the side of the baffle back on to the rear of the cone.

The 45 angle is usually easy to do on thicker baffles (over 18-mm). For those guys on thinner baffles (less than 18-mm) who want to use the 7's front cover and recess the driver, the mount behind the driver will be shallow. In these cases, it may be better to round off the back of the baffle opening. A radius of 2mm to 3mm will help minimise any disturbance around the rear of the driver.

Thanks
Mark.

[buzzforb]

I believe Troels Graverson did a test of this theory and showed that it did not make a significant difference. I could be remembering wrong.

[pizzachef]

Thanks. Sorry to ask such small questions, but I have found Markaudio to be as helpful as any manufacturer I have met to the DIY community. Not to mention having some pretty awesome product. Been running in my bare Alpair 7's at low volume for about 100 hours now, can't wait to get them in a box

[markaudio]

Originally Posted by buzzforb

I believe Troels Graverson did a test of this theory and showed that it did not make a significant difference. I could be remembering wrong.

Hi Buzz, Guys
For Markaudio drivers, it is wise the chamfer the inside of the baffle opening. The rear of the Markaudio driver frames are near wide open to help minimise back wave losses so large side wall with a sharp edge could expose the rear of the cone to reflection.

When I first kicked off making my Gen. 1 Alpair 10's, we kept getting some weird peaks during the anechoic sweep tests. It took me and Evan ages to find the problem. We'd been using a 19-mm thick suspended baffle with a straight cut mounting insert. When we changed to another baffle that used a 3-mm aluminium central mounting plate, ran the sweep test again, the problem was resolved. I'll look at our archive data and see if I've kept an LMS data copy of these tests.

I can't speak for other driver designers since their designs will likely have differing criteria. It could be that for some drivers, chamfering baffle edges isn't needed. But as a handy good practice tip, its usually worth trying to smooth off sharp edges inside baffles, similarly on ports and vents.

Hope this helps.

Thanks

Mark.

[markaudio]

Originally Posted by pizzachef

Thanks. Sorry to ask such small questions, but I have found Markaudio to be as helpful as any manufacturer I have met to the DIY community. Not to mention having some pretty awesome product. Been running in my bare Alpair 7's at low volume for about 100 hours now, can't wait to get them in a box

Hi Pizzachef,
No need for apologies, helping guys with their ideas and projects is the major part of Markaudio section's purpose. Please accept my apologies for sometimes not being readily available to answer all posts.

I'm hoping that more members will share the knowledge and project build experiences so this section of the Diyaudio forum gets close to being self-supporting, me helping with technical supports on the drivers.

Cheers
Mark.

(PS. keep it nice and gently on the run-in. Soft, easy music and cone's shouldn't move - thanks)

[buzzforb]

Very interesting info Mark. Thanks for the advice. I will be getting my 7.3 soon and will start a post about the 7.3 vs 10.2.

[markaudio]

Originally Posted by buzzforb

Very interesting info Mark. Thanks for the advice. I will be getting my 7.3 soon and will start a post about the 7.3 vs 10.2.

Hi Buzz,
Sounds cool, will be interesting to read about your experiences. Hoping you'll show your builds (pics) and offer some tips about your projects.

Cheers
Mark.

[pizzachef]

I have treated the drivers like eggs. Began with 50 straight hours of very low volume Vivaldi from the Four Seasons. Have steadily added music types and a bit of volume. Never saw the cone even budge in the first 100 hours.

[markaudio]

Originally Posted by pizzachef

I have treated the drivers like eggs. Began with 50 straight hours of very low volume Vivaldi from the Four Seasons. Have steadily added music types and a bit of volume. Never saw the cone even budge in the first 100 hours.

Hi Pizza,
Good work. They're about ready for mounting into boxes.
Cheers
Mark