Speaker build - Mark Audio Alpair 7 / Generation3 / Pencil.

[Stresss42]

Hi all, here's a few pictures of my Pencil build for the Mark Audio Alpair 7 full range drivers.

Please note far from finished !! About to apply several coats of filler ( sand down / filler / wet & dry.. etc etc ) to all external surfaces.

Ignore the rough looking sanded ply surfaces - once I'm happy that every surface is near perfect I'll prime / matt black / heavily lacquer.

Hoping to achieve the highest gloss black possible.

Inside both cabinets you'll see black bitumen damping pads, probably a bit of overkill. Also the internal brace isn't really that essential for such a slim
cabinet but I decided to build it. Glad I did - all panels are absolutely rigid / no panel resonance what so ever.
( By that I mean a knuckle tap on the side doesn't sound like a conga drum !!!! ). I'll update when they're all prime coated.

All the best, Steve.

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[synsei]

Nice one Steve, looking forward to seeing them once completed ;)

[John]

Looking good Steve
I not heard these Mark Audio drivers but should sound good I was very tempted to build the 12p in a open baffle with augmented bass

[Stresss42]

Looking good Steve
I not heard these Mark Audio drivers but should sound good I was very tempted to build the 12p in a open baffle with augmented bass

Cheers John, did so much research on them and they're right up my street. Cant wait to hear them....sod it I'll wire them up tomorrow put some damping in the cabinets
and play some music. Cant wait any longer !! Cheers, Steve.

[Tony Moore]

I have the Alpair 7s in my FH3's built for me by Colin Topps. Great drivers, I love 'em.

Great job on your cab building project. They look amazing!

[Stresss42]

I have the Alpair 7s in my FH3's built for me by Colin Topps. Great drivers, I love 'em.

Great job on your cab building project. They look amazing!

Blimey thanks Tony ! I'll be honest I was nervous to post them for some reason !! ?? They took an eternity to build ( made a few mistakes - always on the cards )...
but I have a strong feeling it'll be worth it. Was really tempted to order a flat packed FH3 package but decided to build the pencil design.
( I Read the FH3 review as well - very very impressive, and stunning cabinets ). Absolutely love the idea of no crossover, and the fact that I can simply remove the rear panel and add / remove
damping material and upgrade the internal cabling - in time. Cheers Tony, Steve.

[bobbasrah]

Very nice Steve, but why the damping panels?
Contrary to the comment about the brace piece the designer (Scott?) commented that it was not essential but beneficial, more to do with transfer of energy than damping.
Had intended to build these pensils myself - had the speakers now about a year, never got round to building them at the work digs as it became a nightmare (welding or concrete ok, plywood and glue, no), so brought them home, where lo and behold baltic birch is unknown. Romania seems to be chipboard country, so will have a think on solving that one come the summer.
look forward to update in due course.

[Stresss42]

Sorry guys - duplicated pictures below...computer crashed . . .

[Stresss42]

Very nice Steve, but why the damping panels?
Contrary to the comment about the brace piece the designer (Scott?) commented that it was not essential but beneficial, more to do with transfer of energy than damping.
Had intended to build these pensils myself - had the speakers now about a year, never got round to building them at the work digs as it became a nightmare (welding or concrete ok, plywood and glue, no), so brought them home, where lo and behold baltic birch is unknown. Romania seems to be chipboard country, so will have a think on solving that one come the summer.
look forward to update in due course.

Hi Bob sorry about the late reply...misses got me painting the hallway when I wanna be finishing the speakers !! ?? :steam:

After owning some EB Acoustics EB1 ( bitumen damped - and stunning sound ) and reading loads on the Harbeth website I decided to add the bitumen damping to all ( as much as possible ) internal
surfaces. What I was trying to achieve is minimalising as much panel resonance as possible - as well as adding mass.
To be honest, I would use 18mm MDF next time ( No voids ) - but I would still add the bitumen damping. Also the filling / sanding down / filling etc on the external ply surface area was very hard work.
And for this reason they have only just been finished and ready for paint.
( Plus the ply is prone to a bit of annoying warping ). Over night for no apparent reason one of the rear panels warped - and had to be re-cut.

Edit..by the way I used 18mm hard-wood ply.

Out of interest have a look on Harbeth's website regarding the bitumen damping - they'll explain far more technically than me !! Another couple of pics below - ready now for 4 /5 coats of primer.

All the best, Steve. 11877118781187911880

[bobbasrah]

MDF is certainly a lot easier to work with even if the dust is a complete pain, and it takes spray paint beautifully, have a pair of IPLs at home painted and they certainly look good...
The design for the pensils was quite specifically for baltic birch ply, had asked about mdf before on diyaudio and was quickly and emphatically told no by the designer, the response would not be as designed apparently due to changed panel resonance, hence my curiosity over the damping panels.
Would be interesting to compare the reproduction of your finished version with the design version... anybody local have pensils Steve?

I suppose I had better start searching for a ply supplier soon, other than of the phenolic faced variety...

[Stresss42]

Hi Bob, If you google Alpair 7 Pencil build MDF you'll see a link where Mark Fenlon the owner / designer says mdf is ok, as well as hard wood and plywood. (DIY Audio)
I might email Scott moose and ask the question - but I really believe that if you use a very good quality 18mm hardwood ply it will be fine.
Another reason I applied the bitumen damping was to make the speaker panels as acoustically dead as possible.

Also - the finished version will be exactly as per Scotts' design with the ' holy ' brace but the addition of the 3mm thick bitumen sheets so whether that would differ from
bitumen-less I don't know - I would also love to compare but no-one local that has a pencil build I'm afraid !!

Out of Interest I'll ask Steve from electric beach audio ( amazing Frugel speaker builder - really nice guy ) about the bitumen damping...will let you know. Cheers Bob, all the best mate. Steve

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Primed up, ready for 1st coat of matt black paint.

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1st coat of matt black, although looks like satin ?

2nd coat tomorrow. bit of perfecting / sanding to do. Then Lacquer this easter weekend.

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[walpurgis]

Looks like they're coming along nicely. Even in the basic black, I can see that you're achieving a good finish. I'd suggest a bit of large pore open cell Declon foam in the ports or you'll be providing a nice home to a few spiders.

[Stresss42]

Looks like they're coming along nicely. Even in the basic black, I can see that you're achieving a good finish. I'd suggest a bit of large pore open cell Declon foam in the ports or you'll be providing a nice home to a few spiders.

Cheers Geoff,
Just got home from work and spraying the bottom of the ports, honestly dragging on now - big time. Hard work.
Planning to very carefully lacquer them this week end - good few layers of very thin coats.
( just in case it reacts with the matt Black - never know ! ). Cheers Geoff, I'll post the finished pictures. Steve.

[Stresss42]

3rd and final coat of black. Nearly done.

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[John]

Looking forward to seeing them finished

[Stresss42]

Looking forward to seeing them finished

Me too John - can't wait. Now for the 100 hours or so carefull break in for the Alpair 7.3's.

Hoping I won't have to high pass filter them at around 80 Hz. ( Films / Blu ray my only worry...separate thread ! ) All the best, Steve.

[keiths]

Looking good :thumbsup:

[Stresss42]

Dacron Wadding in ( light / medium only ) plus front cover dowels.

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One of the 1st pictures below - and end result - very very pleased. Drivers in tomorrow plus back cover. Done. Thanks for all your kind comments, can't wait to hear them. ( After break in ). All the best.


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[keiths]

Looking great Steve :thumbsup:

[John]

Looks nice
They should sound good

[Stresss42]

Looks nice
They should sound good

They sound amazing - already. Low volume ( gentle break in ) playing Mike Lindups " Dark Actress " and I'm hearing Cello sounds I simply never heard before - absolute fluid mid range
with the clarity I was hoping for. Seriously hard work with the integral bracing and bitumen damping and the exhausting paint finish - taken me 3 months to build, but worth it. 100 %.

Wonder what I would pay for speakers of this quality - retail. :hmm: Can't wait for the weekend, all the best. Steve.

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[walpurgis]

They look very good Steve. Glad you're pleased with them. :)

[bobbasrah]

Lovely job, although I would hazard a guess only you are aware of those blemishes nobody else sees....
Wonder how they are bedding in Steve?

[Stresss42]

Hi Bob,

Trust me you'd see the blemishes too !! Had an absolute nightmare with the paint finish. Took an eternity. I do plan an some stage to put another few layers of Gloss over the existing satin black
which will hopefull iron out some of the things I'm not 100 % happy with.

Been running them in while at work for 9 - 10 hours a day at low / medium volume. I was playing an album I only just bought - Tori Amos American doll posse and was disappointed.
The whole album sounds compressed to me ? Shame because the track ' Bouncing off clouds ' is such a stunning piece of music. Very confused.
Anyway switching to another disc I know well proved that the Alpairs are the most revealing speakers I have ever heard. Don't get me wrong I've never owned speakers worth thousands of pounds
but these are something special. Looking to add a sub now and intend to high pass them at 150Hz - but that's proving tough because I just can't find a decent passive high pass cross over anywhere. :scratch:
( seperate thread I know ! ). Cheers Bob, all the best. Steve

[Ali Tait]

Try a MiniDSP.

[Stresss42]

Lacquer or leave as is....black Gloss. Even lightly dusting them off will leave small scratches on a non lacquered surface . . . .??

Really like the gloss finish now but very easily scratch-able. Anyone know if the gloss paint goes off over time to a harder surface or should I really
be looking to protect with lacquer ?? Thanks for any advice, Steve.

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Rustoluem black Hammered finish. Stunning.