Alpair 10 - Generation 2 - sneak peek

[norman bates]

any new news on this front ?

[markaudio]

Originally Posted by norman bates

any new news on this front ?

Hi Norman,
Hope your well and having fun with projects. Yup, I'll be with some Japanese guys at a new Japan run factory on 27th April. First 2 drivers on the planning board are:

Alpair 6 - new paper cone model
Alpair 6 - Gen 2 metal cone model
Alpair 10 - Gen 2 standard model
Alpair 10 - Gen 2 special model

As you may imagine, I'm really excited by the prospect of making drivers with more Japanese technical input and support.

Timeline remains around May June. I may take us longer because I'm keen to include more Japanese know-how.

Will keep this thread up to date.

Cheers

Mark.

[norman bates]

excellent.

Take your time, better sound is better sound.


Norman

[FullRangeMan]

WOW... Good news, Looks ALPAIR-10 G2 is another winner fullrange driver, Congratulations to MarkAudio.
Any chance for a 16 ohms voice coil to a parallel twin??
Cheers, Gustavo

[timpert]

Do you already have a (preliminary) parameter set for the new Alpair 10?

[planet10]

In talking with Mark, i believe, with the standard model, he is aiming at keeping the parameters close enuff to the old one as possible, so that existing designs work. If you recall, Mark also has a poll on the decorative bezel. The purpose of shipping it unattached was so that people could upgrade existing boxes with the Mk 2 drivers.

The special edition will need new box designs.

(i beleive Mark is on a road trip to Oz ATM so his response times might get long)

dave

[chrisb]

Originally Posted by planet10

In talking with Mark, i believe, with the standard model, he is aiming at keeping the parameters close enuff to the old one as possible, so that existing designs work. If you recall, Mark also has a poll on the decorative bezel. The purpose of shipping it unattached was so that people could upgrade existing boxes with the Mk 2 drivers.

The special edition will need new box designs.

(i beleive Mark is on a road trip to Oz ATM so his response times might get long)

dave

certainly if the net flange / bezel thickness is along the lines of the Alpair 7s we have on hand (i.e. ~9mm), baffle will need to be rethunk for rebated mounting

[markaudio]

Hi Chaps,
I'm still here but will be away next week to meet 2 customers in Sydney, then time out, returning to Hong Kong on 22nd May.

There's allot happening behind the scenes. First, I've just finished arranging the shipping of 2 metric tonnes of drivers to Germany and a metric tonne to Japan. My back is killing me! A note on this: Virtually all the latest Alpair 7 production has been bought by Germany and Japan. I have only a few pairs in stock. Likewise for CHR-70, CHP-70. All BB4-AL (black coned CHR's) have gone to Germany. Woofs and tweets: over half the stock has gone, this includes the white coned model.

Onto the Alpair 10. Last Tuesday, I had all day meeting with the new Japan operated factory. We have started the planning process for production of this driver, and the Gen 2 Alpair 6. There's still more development happening:

Alpair 10:
1 - Matsubara san will deliver 3 new sets of Prototype Japanese ultra low mass coils. They should arrive from Japan by 10th May.
2 - Matsubara san has now delivered 3 new sets of Mk-2 rear suspensions.
3 - I have finished all my cone work. The new profile tooling is complete.
4 - I have also finished the U cap work.
5 - We are re-designing the rear section of the magnet assembly (motor). Pole and rear plate metal grades are being changed.
6 - New A/B bonding agents are being assessed to the cap to cone connection.
7 - The assembly process is being studied and evaluated by the new factory.

The hope is to produce 2 models of Alpair 10. The first will be close to the existing driver. Some minor gains in efficiency and top end. The 2nd. driver will be a "special". The cone will be mass-minimum so finishing will be different. The coil will be shaved down to less that 800 microns. More efficiency will and increased transients are the goal for this driver.

Here's the last test (March) I did using some of the newer parts so its "work in progress". The data is RAW so please don't kill me. Note the upper range between old and new models, also the minor increase in efficiency. Changes at this stage will be small. There's a little more HF gain and range extension from the Jan 2010 test. This I expected but much depends on the 100 hour and 500 hour test. We are close to the wire on how much mass can be shaved off some components. As I often say, I'm not in the business of making "boom bang abang" drivers.

Expect the special model to have T/S something around the figs below. But don't take them as fixed. I still want to work on increasing Vas and Total Q. Lots of alchemy still to do:

LMS - Proto-003-0.08CCAW-A1.5
Revc= 7.200 Ohm
Fo= 46.381 Hz
Sd= 8.825K mm
Vas= 15.940 Ltr
Cms= 1.441m M/N
Mmd= 7.031 g
Mms= 7.508 g
BL= 6.516 T.N
Qms= 1.315
Qes= 0.387
Qts= 0.299
Levc= 74.323u H
No= 0.451 %
SPLo= 89.060 dB

Must dash, lots do do before I fly.

Cheers

Mark.

[markaudio]

Hi guys,
A note on mounting the new Gen 2 drivers. Ideally, the side wall thickness of the front baffle that extends behind the driver's mount should not exceed 8-mm. On our anechoic tests, +10-mm baffles disturb the Gen. 2 drivers by some +/-2dB greater variance in the LF range (<800Hz). Whereas keeping the side walls to around 8-mm or less removes the influence.

Please bear in mind that I designed the frames for minimum air resistance out from behind the cone. So keeping the baffle mount on the thin side around the back driver is worth doing.

For guys using thicker baffles, chamfer the back edge with the largest radius possible to reduce the possibility of a return wave hitting the rear of the cone.

Hoping my quick pic will help.

I'll do a sticky post on this once I've finished the Alp 6's and 10's.

Cheers

Mark.

[markaudio]

Hi Guys

I just been reminded to explain the reasons for much of my tweaking. Sorry this is quick, time is short but briefly........... See - graph - green areas marked 1,2 and 3.

1 - the +dB hump helps to off-set baffle step losses. Less correction (if any) is needed when using my drivers that have this feature.

2 - Lowering the output in the mid range helps the reduce "shout" and "sibilance. Vocals benefit with more balance. In particular, I can't stand vocal sibilance...sssssss. Drive's me nuts so I tweak driver output in this part of the range to help reduce the phenomenon.

3 - Rising HF response usually from 5-kHz up gives more choice on on-off axis positioning. You want more brightness in your music - toe in, want more Jazzy smooth, toe out. I personally tend to listen at about 10 degrees off axis. Suits my room set-up. Pick you position.

I'll do another sticky when time permits.

Cheers

Mark.