Markaudio Alpair-5 Giraffe Build

[planet10]

I can confirm that the copper A5.2 i just got were sans dimples, which confirms to me that they are pre-production prototypes.

dave

 

[Bigun]

There almost certainly being other changes between the old 5 and this one - while one could probably compare the T/S parameters between the two and surmise which differences are strictly due to the elimination of spider and voice coil, etc., exactly how any found changes would explain difference in sonic performance is another matter.

No voice coil = no voice

 

[chrisb]

thanks for catching that - it should have said "and changes to voice coil / former, leads. etc" - what Mark often referred to as the "drive train" - i.e. all the moving parts.

 

[Dr1v3n]

...

dave

Dave, how do those units sound in (PVC?) compared to wood?

 

[planet10]

Designed as a midTL it was more limited by the old A5 i think than PVC vrs wood. The cylindrical PVC is very stiff and worked fine as far as the system goes. I may still have the pipes (depends whether they disappeared during th ebig clean-up while i wa sin the hospital), The A5s are in Alaska.

We have retrofitted boxes with a similar PVC midTL out the back. All a matter of what compromises need to be made to get the job done.

dave

 

[Dr1v3n]

I was just wondering if the round cylinder had any noticeable audible improvements over a square box? I'm thinking more cancellation and less standing wave type problems with the cylinder.

PVC, or any similar plastic, isn't cheap. So I appreciate your input greatly!

 

[planet10]

Well certainly i’d choose PVC before MDF, which i do not think makes a very good speaker box. PVC would be lighter, have less wall thickness to deal with, yet at the same time be stiffer due to the circular shape.

A square vrs circular cyclinder brings a whole differen tset of plus/minuses.

dave

 

[Dr1v3n]

You mentioned some positives. What would be some negatives?

 

[planet10]

A circular cross-section will have 1 strong side-to-side resonance. A square cyclinder would as well. If filled with damping should not be an issue.

dave

 

[craigtone]

How did you guys damp your giraffes? I have a doubled layer of quilt batting but now that they are breaking-in a bit, midbass is a touch boomy.

 

[planet10]

They should be volume filled with well teased poly fluff — the amount determined by listening… more density depresses the low end and reduces the ripple. There is some gain in the bottom so it does need to be damped at least somewhat. Room, room placement, listening preferences all play a roll.

dave

 

[chrisb]

Honestly, I've done too many builds to remember - in the case of the A5.2, I think there was a total of 5 different builds, including the Giraffes and FH lites in one week. I would have followed the notes on drawing - which I don't have at hand - probably just some 1/2" UltraTouch felt lining the walls, and some loose AcoustiStuff fibre?

Dave or Scott can confirm those details - which begs the question, was there even an official CAD , or just a gin-soaked cocktail napkin sketch. ?

 

[planet10]

http://wodendesign.com/downloads/Giraffe-A52-MLTL-0v99-081015.pdf

An externally hosted image should be here but it was not working when we last tested it.

dave

Edit: i do see that the front view shows the “frame” for a removable back (as in the Pensils), but the side view doesn’t.

 

[Bigun]

A circular cross-section will have 1 strong side-to-side resonance. A square cyclinder would as well. If filled with damping should not be an issue.

dave

Perhaps, with the circular one, the majority of resonant modes will have peak amplitude at the axial centre of the tube and some damping material at that location could prove particularly effective ??

 

[planet10]

Well yes, i’d stuff the entire cylinder. My ap is most typically midTL and i like to stuff them till aperiodic.

dave

 

[craigtone]

So far I have found placement with respect to listener more important than room placement. I prefer about 6' from listening position and 6' apart with no toe-in. This seems to give the best balance with decent bass and a VERY wide (~12') soundstage.

Now that they are broken-in a bit, I popped on some Megadeth Countdown to Extinction and Rage Against the Machine Killing in the Name of yesterday at moderate volume and I was blown away! My old Alpair 12 pensils could not keep up with faster music but these little Alpair 5's have NO problem with whatever is thrown at them!

I am currently running them off my 45SET amp and find that I lost dynamics vs the Gain Clone. I am now leaning towards a Pass Amp Camp build for these which I think would be their sweet spot as they did sound phenomenal on my buddies Aleph J when we first tested them out.

 

[chrisb]

As sweet a piece as the ACA is, I'm thinking you'll find 10W+ to be the start of the golden zone for these little guys. IIRC, when I did my quickie listening test to the 5 or 6 designs that I blasted together for this driver last year or so, it was with my Tubelab Simple PP EL84 (15-ish WPC) . I can certainly imagine a 45or even 2A3 SET would be a bit light on grunt for these.

 

[scottjoplin]

yah, sumpin like that - scottj is currently on a campaign to rid the term FAST from our lexicon, and since I've frequently mentioned my dislike for the term, I should probably support that ?

Good show old bean