Alpair 7MS Cabinet Dimensions (Quick Check)

[Napalm44]

Hi,


I've ordered a pair of 7MS's, and as a first 'proper' project, I'm building a set of desktops for low level listening.

I'm trying to do this pair 'right' - first time for everything 🙂, can someone check my measurements and tell me if I'm in the right ballpark?

I'm using the guide at diyaudioandvideo.com


The official speaker specs

The enclosure calculator asks for a 'Fs' measurement. I've used the 'Fo' from the specs as it's the only one in Hz - is this wrong?

Putting those into the enclosure calculator tells me to aim for an 8.77 ltr box.



Speaker displacement I get at 0.21 ltrs



I know I want the speaker fronts 6" wide and 17" high. Using 3/4" stock and no bracing, that means the box is 9.36” deep



So 6"x17"x9.4" - does that sound about right?

Thanks 🙂

 

[planet10]

I am currently working on the A7ms miniOnken planset. The optimum volume i am using is 9 litres. It turns out that the volume the driver takes up is pretty close to exacty the extra box volume you get from chamfering the back of the driver cutout 45°.

6"x17”x9.4” with ¾” material yields 9.03 litres, just about perfect. I would suggest that with a box this large you may want a brace.

dave

 

[Napalm44]

That's great to know, cheers Dave.

Managed to get the first bit, of my first speaker, generally correct - it's surprisingly satisfying 😀

I'll now look into the brace design.

Thanks again.

 

[ssportclay]

Is there a 13 liter CGR box in the future or is smaller better ?

 

[planet10]

I have done the 1st pass of A7/11ms boxes. Except for the millSize A7ms box all are 9 litres and the set does include CGR for both. While a larger box is not suitable for the A11ms, it may be possible to fit the A7ms in 13 litres althou the sim does not give quite as nice a shape it is very close to the Mar-Kel for the EL70 so i will do one if someone wants to build one. These 2 plansets are currently in beta so if you want to participate send me an email. This alignment also makes it suitable for the Compact FLoorStander.

The current beta testers plan on doing the full on trapezoid for the A11ms, and the milliSize for the A7ms. Be nice to get a couple other builds particualrily for the A7ms which has a wider range of boxes.

 

[Napalm44]

Here I go down the rabbit hole. 🙂

Do I need to include a baffle step compensation circuit?

The calculation says f3 =760 hz, (1.5 mH inductor and 7.2 Ohm resistor)

(look at me, bandying words around like I have half a clue)

Thanks

 

[planet10]

Listen first.

dave

 

[Napalm44]

😀

 

[GM]

CGR?

Don't recall this one...........

TIA,

GM

 

[planet10]

CGR = Classic Golden Ratio.

The CGR cover page (for A7ms). This is a 9 litre box, there are also smaller & larger ones.

dave

 

[Napalm44]

I've been playing around with some renders, trying to decide what look I want, and I thought you'd get a kick out of these Dave.

I was going to put one in the 'Whats your latest build' thread and see if I could fool anybody 😀

 

[chrisb]

I think I like the dark cinnamon colour of the far left pair the most.

 

[GM]

CGR = Classic Golden Ratio.

Ah! Too many monikers nowadays to remember if not used regularly. 🙁

Can't recall; you ever use the pioneer's industrial 1:1.414:2?

GM

 

[GM]

Considering the driver's color, the blue-gray/gold works best overall for me, but all are keepers! 😀

GM

 

[planet10]

you ever use the pioneer's industrial 1:1.414:2?

Not that, i used 2^1/2 almost as standard but i choose a 3rd ratio (irrational number) that did not yield an even multiple.

dave

 

[GM]

Thanks! In theory, even better of course. 😉 Seems the pioneers were more interested in using what folks find architecturally pleasing as an acceptable trade-off.

GM

 

[yomgaille]

Hi, has the CGR been finalized for Alpair 7ms?

I need a slim enclosure for a smallish room and I think the CGR is the way to go, a file seems to have been posted by Dave in this thread but doesn't show anymore, and frugal-phile.com only has CGR for 7 and 7.3, but now 7ms is the only version largely available.

Thanks for all the info that I've already been able to gather on this forum 🙂

 

[planet10]

I have the wide one done. Pretty easy to do a slim one to add to the planset.

email me if you wuld like it to happen.

dave

 

[yomgaille]

Great, email sent 😉