Initial Impressions: Alpair 12 full-range driver by Mark Fenlon

[creekkumar]

here are pics.....

[italynstylion]

Bravo Creek. Job well done!

[markaudio]

Hi Creekkumar,
Excellent work - well done! Wish I could take time out to listen to your system.

Here's a possible suggestions for you. It may help to improve the flow coming from the back of the driver's cone if you open up the mount a little more. The Alpair 12's cone is very sensitive, best try to minimise any wood edge profile that might reflect part of the cone's pressure wave back towards it.

I've Photoshoped your pic to help illustrate my suggestion. Hope this helps

Cheers

Mark.
Markaudio

[creekkumar]

Thanks Mark for you suggestion. The inside circle diameter is 5.75 inches which is outer diameter of suspension where curvature stops and is glued to the frame. The wood thickness is 10 mm after trimming for driver. My only intension was to provide enough mechanical strength to wood by providing enough width and as the internal edge ends before suspension starts theoretically it should not hinder air flow. But I could be wrong, pls let me know where the edge should be in inches to not to effect air movement.

Another request is if you can share waterfall and THD measurement with us that would be great(like zaphaudio.com have) I am sure it would be way better than other drivers but this information would help all potential full range buyers in making buying decision easier.

I am assuming you have seen ads of AT&T and Verizon on TV about them trying to convince how one is better than the other. I believe quality product with right tools and marketing strategy provides guaranteed & sustainable success. Above tool can be one of them.
Thanks & Regards
Creek

[markaudio]

Hi Creekkumer,
Please take a look at the attached pic. You may have a recess profile similar to this illustration? Ideally, its best to have a radius facing out and away from the cone. Depending on the wood thickness but something around R=5-mm is nice. It may be useful to consider opening the cut-out to 6.65 inches (169-mm). This would make the hole size just shy of the legs on the Alpair's frame (as per my earlier pic). But if the music reproduction is clean and clear under load, then its OK to stay as is.

I'm hoping to purchase a whole new measuring system this year. I had hoped to do it last year but the economic slide put pay to that. Last time I looked at Zaph's site, a cheap Berringer mic was in use. Not wishing to disappoint folks but it takes a pile of money going into anechoic chambers, hardware, software and mics to get the job done properly. Data generated from lesser systems shouldn't automatically assumed to be totally reliable and accurate.

For now, I've got access time to a purpose built anechoic chamber, LMS, signal measuring + my own bespoke equipment that deals with cone and power-train development.

In the meantime, there's a good number of folks on this forum and in Germany and Japan who will vouch for the accuracy of the existing data that I provide.

Being an Mech Eng. by nature and training, I'm guessing you'll know from which direction I'm coming just by owning and using a pair Alp12's. I hope you get many hours of pleasure from them. I'm not saying my drivers are the best in the world, but am I'm trying my best to build in more performance and value for money.

Cheers

Mark.

[CLS]

Late to the party....

Originally Posted by creekkumar

....

Comparing to my active Klipsch system, it has its own class. In details at top end Alpair has edge. Dynamics is almost equal to Klipsch with Klipsch having the edge. For bottom obviously Klipsch wins but in apple to apple comparison Alpair has more clarity and definition. In imaging both are very good but not the best (not sure if it is my system or my room)
...

It's amzing that a single cone fullranger has similar or better top end detail and overal dynamics of a multi-way active horn system !!

[ultrakaz]

Originally Posted by markaudio

Hi Creekkumer,
Please take a look at the attached pic. You may have a recess profile similar to this illustration? Ideally, its best to have a radius facing out and away from the cone. Depending on the wood thickness but something around R=5-mm is nice. It may be useful to consider opening the cut-out to 6.65 inches (169-mm). This would make the hole size just shy of the legs on the Alpair's frame (as per my earlier pic). But if the music reproduction is clean and clear under load, then its OK to stay as is.
Mark.

If the airflow/back pressure is hyper critical why not design a driver flange that is larger while keeping the same basket size? Also, I've often wondered, especially when the flange is very thin as in my Alpair 5, why the designer would do something like this, which leads to a smaller margin of error when cutting and rebating the hole. I can understand the purpose of a narrow flange if driver spacing is important as is the case with tweeters, although I've seen tweeters with large flanges. Furthermore, by creating a larger flange, the designer might be able to influence diffraction directly around the driver by altering shape, texture, material, etc.

[chrisb]

Originally Posted by ultrakaz

If the airflow/back pressure is hyper critical why not design a driver flange that is larger while keeping the same basket size? Also, I've often wondered, especially when the flange is very thin as in my Alpair 5, why the designer would do something like this, which leads to a smaller margin of error when cutting and rebating the hole. I can understand the purpose of a narrow flange if driver spacing is important as is the case with tweeters, although I've seen tweeters with large flanges. Furthermore, by creating a larger flange, the designer might be able to influence diffraction directly around the driver by altering shape, texture, material, etc.

no doubt designers of drivers and speaker enclosures relish all this second guessing

[hayenc]

Especially when the Alpair flanges are some the best designed I have worked with (at least in building with the 7 and the 12).

[Jozua]

Creekkumar

How does the speakers sound with your transistor amplification ?

I have a friend with Fostex FR drivers in 7 foot boxes which are very listenable with a very good soundstage but lacking in ultimate detail and bottom end tightness which I have in my system but I do not have his consistent soundstage.

Feedback will be appreciated.


Jozua






Regards


Jozua