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-   -   Alpair 6 - Gen 2. - Prototype 1 (http://www.diyaudio.com/forums/markaudio/162840-alpair-6-gen-2-prototype-1-a.html)

markaudio 9th March 2010 07:59 AM

Alpair 6 - Gen 2. - Prototype 1
 
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Hi Guys,
I've not forgotten those who love the Alpair 6 so here's a peak at the new Proto. There's a few changes with this driver, most obvious is the cone. Its cone profile No-154 from my collection. This cone has taken allot of work. Its paper. It's Japanese origin with Taiwanese production. The Multiform process has been taken a stage further so much of the forming is now double pressing. Note the colour. The dyeing process is critical to rigidity of the cone, along with reduced mass.

Other changes will follow with the addition of a Matsubara San rear suspension. Those that follow my work will note the Lui Yi Ping front suspension.

Performance enhancements (compared to the Gen 1 driver) are:
Wider range - the top end extends another 3-kHz (22-kHz)
Linearity - improved - These are RAW results. Near flat across the range.
Efficiency - Up by 2dB over the Gen 1 model.

Here's the T/S results:

Revc= 3.600 Ohm
Fo= 78.166 Hz
Sd= 3.632K mm
Vas= 3.155 Ltr
Cms= 1.684m M/N
Mmd= 2.317 g
Mms= 2.443 g
BL= 2.613 TM
Qms= 2.925
Qes= 0.635
Qts= 0.522
Levc= 9.320u H
No= 0.232 %
SPLo= 86.477 dB
Xmax = 3.2-mm (1 way)
Pwr = 14 Watts (nom) 28 Max.

Scott has been running the No2 set of these protos for a few weeks. I'll see if he has time to comment. Norio has been running the No.3 set, I'll ask him for an up-date. I'm running the No.1 set but will leave it to these 2 guys to say more.

We are around 2 to 3 months away from final production depending on suspension and more coil developments.

Cheers

Mark

Scottmoose 10th March 2010 03:38 PM

Well now, the A6 Mk2 (paper cone) is an interesting little driver. In size terms, like the original A6, it's a bit of a one-off; there aren't all that many units of equivalent size. Not that that's a problem; just an observation that attempting to draw comparisons to most other units will be meaningless.

Observations are on the prototype units, which are still a work-in-progress, but show considerable promise. Efficiency and linearity are both improved over the original A6 (which I liked); it's a well balanced unit, and should appeal to those who desire a modestly sized mid-tweet, as Mark hasn't put as much in the way of response-shaping into the basic response, as you can see from the plot above. Some people will prefer this; just be aware that they're not quite as forgiving of poor quality material as the original. On the other hand, they don't crack up like the originals did at the top of the telephone band when being pushed hard, so, as always, swings and roundabouts.

Like the original, they notionally go low for a small driver; at least in terms of Fo (Fs), and have a fairly substantial Xmax. That doesn't necessarily mean it's a good idea to take them down that far; you might get away with it with a compact monitor, but we're still talking a very small driver here, so one has to be realistic. If it's to be run solo, I'd favour a horn, or a small sealed / aperiodic cabinet, although a sympathetically tuned BR is also OK for monitor duties (which incidentally, they're good at).

They take a long time to run in; substantially longer than, say, Fostex units. This isn't subjective, Mark and I have had several lengthy discussions on the subject and the reasons for it (for reference, it's due to the construction of the cone). 200 hours will be needed before you get a good idea of everything they can do, and note that if, during the running in period, you have to leave them for a day or so with no signal, then you'll likely end up a few days further behind schedule.

I don't particularly like subjective comments on the sound; you can infer roughly what their behaviour is like from the above -a nice, small, well balanced driver, with low distortion for a unit of its type. Like most of the MFA drivers, its behaviour is very consistant over varying input levels, probably through the concentration on the power-train and mechanical detailing, and as noted, they are more stable than the original metal cone units at high levels. Overall, I'm impressed; sufficiently so that my feedback to Mark a couple of weeks ago was to the effect of 'build it' (as in commercially). And with the Matsubara-san rear suspension planned for the production units, those are going to edge the prototypes I've been playing with for the past two months.

gbbryant 6th May 2010 05:27 PM

Hello,

Very interested in creating a line array with the Alpair 6 (rectangular). Any update on when the new ones will be available?

Thanks.

Scottmoose 8th May 2010 03:20 PM

Mark's on holiday at present, I'll do my best to field what questions I can in his absense.

I believe the A6 Gen 2 will be available mid - late summer. To the best of my knowledge, they will be circular frame only, at least initially, although the square frames may get a look-in at a later date. Don't hold me to that, I may be mistaken, but that is the state of play as I understand it at present.

As it happens, I'm working on two official MA line array designs at present (as in proper line arrays, not the little 4 driver things). They should appear in the next month or so.

markaudio 9th May 2010 12:02 AM

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Hi Guys,
Greetings from "Down-Under". I'm in Sydney right now, tomorrow we're heading north towards the bush so no broadband connection.

Scott, many thanks for filling in on the info front. I'm hoping to make both round and rectangle framed Alp6's. I'll be talking to the dealers when I return from holiday, see what quantities they can take.

Talking on music, take a look at the pic. Its the poster of Sydney Symphony orchestra's Rogers and Hammerstein production, George Daugherty conducting.

Rodgers & Hammerstein on Stage and Screen

I'm so glad we went to see this production, what a fab night! Great live music, the orchestra was synchronising with the vocals coming from the original MGM sound tracks. Great piece of acoustic engineering as the output from the line-arrays were nicely balanced with the hall's natural acoustics.
Very interesting to be in the main hall of the Sydney Opera House. Its shape of the hall favours wood-wind and brass sections over strings, most interesting. We were in a box sited stage right, acoustic balance was quite good considering the hall in some 30 years old.

Cheers

Mark.

Scottmoose 9th May 2010 07:20 AM

Quote:

I'm hoping to make both round and rectangle framed Alp6's. I'll be talking to the dealers when I return from holiday, see what quantities they can take.
So much the better. :)

Musik007 13th May 2010 04:20 PM

Hi Mark,

You listened a very good concert in Sydney. I also like to listen concerts. In 18th June, there is a concert which is worthy to listen in Hong Kong. Massaki Suzuki will perform Mozart and Mendelssohn in City Hall. I bought the tickets.

Hong Kong Philharmonic Orchestra

Musik007 28th June 2010 05:34 PM

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Hi Mark,

I just built a pair desktop Alpair 6 (original) bookshelf. The cabinet size is 150Wx200Dx250Hmm. The box is very solid as it is 20mm oakwood. I've just listened 2 hours. The sound is what I like, natural, detailed, balanced. The bass is reasonable for such small sized cone. I would like to compare this original Alpair 6 with your new version in paper cone.

Cheers,
Tony.

Musik007 28th June 2010 05:38 PM

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Good finishing on cabinets for this pair.

markaudio 28th June 2010 10:42 PM

Hi Tony,
I moved your Alp6 posts to this Alp6 thread.
Cheers
Mark.


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