NEW MarkAudio Alpair 12P Gen2 paper coned drivers.

Dedicated to those large boxes at one end of the room
zman
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#16

Post by zman »

Thanks Colin. BTW, you indicated about a month back that you would be building these 2 months later.

So with 1 month gone, look forward to updates soon! :)
chrisby
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#17

Post by chrisby »

Toppsy wrote:Zia,
it's in the 'Pencil' rang size wise, so a small floorstander. That's all I can say. Certainly NOT in the range of the big BVR speakers and a double mouth horn it certainly aint.

Well, as noted in a prior post above, the (by now) "conventional" SuperPensil is no slouch, although the short height cabinet does place the driver a little low - a simple trestle base (4" or so) would probably fix that.

Jeff hasn't had the chance to put the parts together that we cut out 2 weeks ago - something about "yard work" :wink:
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Toppsy
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#18

Post by Toppsy »

Chrisby wrote
Well, as noted in a prior post above, the (by now) "conventional" SuperPensil is no slouch, although the short height cabinet does place the driver a little low - a simple trestle base (4" or so) would probably fix that.
Just my thoughts when Scott sent me the prototype specs with dims. So when I drafted up a set of plans I incorporated a small false base, filled with white polystyrene foam block, to bring the height of the driver nearer to seated ear level.

Scott got back to me saying that wouldn't work as the design relied on the port opening being close to floor to achieve good base lift, or something on those lines. Anyway, Scott agreed as spec'd the driver would be a little too low so he has gone away to have a think how to get around this. Knowing Scott's design prowess I'm sure he will come up with a solution. So for now I only have a small standmount waiting in the wings for my pair A12P's.
zman
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#19

Post by zman »

Colin, Chris,

I am curious - when it comes to driver height we seem to prefer something closer to ear height (when seated of course). A full-range driver with good dispersion characteristics - how much is it likely to suffer by being placed 4 inches down?

- Zia
zman
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#20

Post by zman »

To add to my previous post, tilting the front baffle by 5 degrees should also help?
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#21

Post by chris661 »

I think this is often down to personal preference.
I like the sound to come from a little above ear height, to give it a more live-on-stage feel.

4" down compared to normal listening distance will make a tiny angle, so HF response is unlikely to suffer.
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#22

Post by zman »

Colin,

Time flies... :) Any update from Scott on the smallish floorstander for the A12P growing a bit taller for the collective liking of the DIY folks?

- Zia
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#23

Post by Toppsy »

Hi Zia,
Nothing on that particular design yet unfortunately. I believe it requires a total rethink to get the concept to work in a taller box so I wouldn't hold your breath. I'll ask Scott though if any progress.

In the meantime to get these drivers in a working box I am going to build a small vented standmount speaker that Scott designed for this driver. I'll feature this build when I find the time next month.
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#24

Post by chrisby »

zman wrote:Colin, Chris,

I am curious - when it comes to driver height we seem to prefer something closer to ear height (when seated of course). A full-range driver with good dispersion characteristics - how much is it likely to suffer by being placed 4 inches down?

- Zia
you may have seen my own and StevenZ's comments on this subject at DIYAudio forum - neither of us found the lower height to be a huge issue, although Jeff Willing did notice a decrease in LF output when raised on a 4" trestle bass

tilting the entire cabinet (5` does seem to be a golden number for that) would likely be a reasonable compromise
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#25

Post by zman »

Toppsy wrote:Hi Zia,
Nothing on that particular design yet unfortunately. I believe it requires a total rethink to get the concept to work in a taller box so I wouldn't hold your breath. I'll ask Scott though if any progress.
A redesign complicates things. But we all know Scott to be a creative kind of guy :). In the meantime, from what we are hearing from folks who've built them, the Pensil and Super Pensil for the Alp 12P are winners.
Toppsy wrote: In the meantime to get these drivers in a working box I am going to build a small vented standmount speaker that Scott designed for this driver. I'll feature this build when I find the time next month.
Hmmm... that's interesting, but would have loved to hear your impressions with a Pensil/Super Pensil - you've been on a roll with Dales and the differences in presetation would have been interesting to know.
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#26

Post by Paul Barker »

chrisby wrote: you may have seen my own and StevenZ's comments on this subject at DIYAudio forum - neither of us found the lower height to be a huge issue, although Jeff Willing did notice a decrease in LF output when raised on a 4" trestle bass

tilting the entire cabinet (5` does seem to be a golden number for that) would likely be a reasonable compromise
Can you picture going up to a flortist and saying. "Sorry love can you lean back 5 degrees", or "just stand on this 4in box so I can get into the sweet spot?"
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
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#27

Post by Toppsy »

zman wrote
Hmmm... that's interesting, but would have loved to hear your impressions with a Pensil/Super Pensil - you've been on a roll with Dales and the differences in presetation would have been interesting to know.
The difference would be like chalk and cheese. Very different presentations in sound completely and any comparisons, would in my opinion, be pointless. From my perspective I would gain nothing by building a pair of Scotts Pencils or Super Pencils for my A12P drivers as plans for these are freely available to the DIY community.

I have a mate who liked very much what he heard from the A12P's when they were in the open boxes whilst being run-in. He wants to come over my place when I have the small standmounts built to listen to these. If he likes those then the idea is to do a larger floorstaning speaker using the A12P with bass helper. Either a isobaric pair of 8" bass drivers or a couple 8" bass units wired in series mounted on the front baffle. As yet this is still in the 'ideas' to develop stage but will get built in one form or the other. This is apart from the floorstander design Scott originally proposed. So lots in the pipeline. It just takes time to do these things with all my other work commitments.
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#28

Post by chrisby »

zman wrote:
A redesign complicates things. But we all know Scott to be a creative kind of guy :). In the meantime, from what we are hearing from folks who've built them, the Pensil and Super Pensil for the Alp 12P are winners.



Let's not aggressively second guess Scott on this, but here I go: extrapolating what I've heard from numerous of his and Dave's single driver designs over the past 5 or 6 years, I can't help but wonder about an Avebury style for this driver

That'd definitely not be a "too short" floorstander, and assuming the same height as Silbury(Alp10) & Avebury (original 12M) would centre the driver at 36", or 6" higher than the Pensil / Supers.

For those not relishing the thought of a 72" tall enclosure, it wouldn't be all that difficult to build a slanted Pensil - 5dg seems to have worked very well for the FH3 and the earlier Tysen - but if one was of a puckish inclination, build it at 3.97deg and call it a Pisa

yup - it's that slow at work today

cheers
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#29

Post by Lorienblack »

Did those designs surface for the 12p? I just picked up a pair, and ultimately had them destined for a set of super pensils, but I'm open to new ideas :)
zman
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#30

Post by zman »

Lorien,

Good to see you at this forum also - the DIY fever continues :)

IIRC these are the speakers that Colin built:

http://www.audio-talk.co.uk/phpBB2/viewtopic.php?t=4362

And here is a link to the plans:

http://www.madisound.com/pdf/SmallRefle ... 191012.pdf
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