Alpair 10.2 in 8 liter sealed - Too good to be true?

[rongon]

In WinISD, I put the T/S parameters from the Mark Audio Alpair 10.2 into an 8 liter sealed cabinet and got a pleasant surprise. It says the F3 should be about 72 Hz, -6dB at 56Hz, -10dB at 43 Hz, with a Qtc of 0.74. 87dB sensitivity. That's pretty darned good, I'd say.

Did I do that right? Am I missing something? That all seemed too easy!

I have a pair of 8 liter cabinets I can start out with, so I can actually afford to do this...

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[vinylkid58]

I get the same result in WinISD.

jeff

[planet10]

Mine shows f3 ~5 Hz higher

[rongon]

Originally Posted by planet10

Mine shows f3 ~5 Hz higher

Hmmm... Even so, F3 = 77Hz is still acceptable for a start. That's as low as many small bookshelf 2-ways, and better efficiency than many.

I pulled the trigger and bought a copper pair from Madisound. This should be fun.

In WinISD, it doesn't show much improvement by going vented in that small a box. I just want to give these drivers a fair audition. I've heard Jordan's and loved them. I'm hoping these will be in the same family. If so, I'll be one happy audiophool.

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[chrisb]

Originally Posted by rongon

Hmmm... Even so, F3 = 77Hz is still acceptable for a start. That's as low as many small bookshelf 2-ways, and better efficiency than many.

I pulled the trigger and bought a copper pair from Madisound. This should be fun.

In WinISD, it doesn't show much improvement by going vented in that small a box. I just want to give these drivers a fair audition. I've heard Jordan's and loved them. I'm hoping these will be in the same family. If so, I'll be one happy audiophool.

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don't let a computer sim dissuade you from trying a "vented" enclosure (there's far more latitude in that genus than with sealed)

use the existing cabinets as break-in boxes while you hike the trail of pursuing a different design?

be aware that due to their basket / flange design, all Alpairs share the characteristic of needing a larger enclosure than the modeling would suggest as minimally acceptable, just to fit in the box

[planet10]

Originally Posted by rongon

Hmmm... Even so, F3 = 77Hz is still acceptable for a start. That's as low as many small bookshelf 2-ways, and better efficiency than many.

And well suited for small LCR + surrounds in an HT if set to small.

dave

[chrisb]

Originally Posted by chrisb

don't let a computer sim dissuade you from trying a "vented" enclosure (there's far more latitude in that genus than with sealed)

use the existing cabinets as break-in boxes while you hike the trail of pursuing a different design?

be aware that due to their basket / flange design, all Alpairs share the characteristic of needing a larger enclosure than the modeling would suggest as minimally acceptable, just to fit in the box

let me elaborate - it's the extra wide composite resin flange of Mark's drivers that causes some fun when it comes to making a box wide enough to fit, while keeping the net volume on target for some designs - this is what prompted the trapezoid shaped boxes such as:

[rongon]

My "break in box" has a baffle width of 220mm. The specs show Alpair 10.2's mounting ring diameter as 165mm. Should be OK, right?

BTW, I love the enABled baffle ring on those boxes. Are those little blocks of the same dark wood (walnut?) as the ring is made of? Cool.

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[chrisb]

Originally Posted by rongon

My "break in box" has a baffle width of 220mm. The specs show Alpair 10.2's mounting ring diameter as 165mm. Should be OK, right?

Should be fine - it only starts to get really hairy with something like the narrow trapezoid shapes, in which case there's not a lot of margin between the flange and chamfered edges ( i.e approx 6.5mm each side if using the extra bezel ring, and 8.4mm per side if not)

BTW, I love the enABled baffle ring on those boxes. Are those little blocks of the same dark wood (walnut?) as the ring is made of? Cool.

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yup, depending on the angle of light and grain on individual blocks, they either almost disappear, or stand out - Bernie's a far more patient guy than I

[von.ah]

Those wood freckles are sweet. And it looks like Dave cleaned his lens. :P