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#1 more speaker porn

Post by ed »

or not......

I was in dire need of a new pair of near fields so fortunately Scott was off loading a pair of markaudio alpair 10p....
so far so good...until........the dust extraction blew up(Vax mach 1) oh waily waily......

How well I remember giving away my 4" extraction unit together with all pipe work....not to mention all the space of the workshop.....oh waily waily.....if I hadn't know such riches I could live with being poor.....I must sit down.
mon v3as.jpg
a bit of a departure for me....to include the monacor ribbons I have on the shelf waiting for a rainy day.
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#2 Re: more speaker porn

Post by Cressy Snr »

ed wrote: Fri Apr 20, 2018 4:55 pm or not......

I was in dire need of a new pair of near fields so fortunately Scott was off loading a pair of markaudio alpair 10p....
so far so good...until........the dust extraction blew up(Vax mach 1) oh waily waily......

How well I remember giving away my 4" extraction unit together with all pipe work....not to mention all the space of the workshop.....oh waily waily.....if I hadn't know such riches I could live with being poor.....I must sit down....
I'll sit down, sit down, sit down, sit down, doooown down, in sym - pa - thee...

SWIDT :wink:
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#3 Re: more speaker porn

Post by ed »

A bit of progress. I'm quite pleased so far as the whole shebang is just scrap and left-overs. Now for installation, testing and tuning.....fingers crossed.
mon v3.jpg
Oh, and finishing and polishing....how could I forget that.
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#4 Re: more speaker porn

Post by Dave the bass »

Pfffffffffftttttttttttttt, Mega-shoddy plus wun.
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#5 Re: more speaker porn

Post by Cressy Snr »

Gigashoddy! :D
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#6 Re: more speaker porn

Post by Scottmoose »

Very pretty indeed. :)
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#7 Re: more speaker porn

Post by steve s »

Really nice Ed..
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#8 Re: more speaker porn

Post by IslandPink »

Elegant and functional - love the front panel thickness !
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#9 Re: more speaker porn

Post by Toppsy »

Top notch workmanship as ever Ed. They do look rather elegant in keeping with your usual signature build style.
I expect these will be very good as near field speakers. Of the A10 drivers I have to say I prefer the paper coned version you have over the metal coned and your choice of tweeter in the Monacor Ribbon will compliment the Alpairs very well. Looking forward to hearing these at Owston.
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#10 Re: more speaker porn

Post by ed »

Toppsy wrote: Wed May 09, 2018 8:07 am Top notch workmanship as ever Ed. They do look rather elegant in keeping with your usual signature build style.
I expect these will be very good as near field speakers. Of the A10 drivers I have to say I prefer the paper coned version you have over the metal coned and your choice of tweeter in the Monacor Ribbon will compliment the Alpairs very well. Looking forward to hearing these at Owston.
Theanks Colin...

I've got my fingers crossed for the 10p. The a10/2 were superb but the A10/1 which I gave to Scott were a tad disappointing, you may have heard them. They couldn't decide if they wanted the port blocking or not, and either way sounded very congested to my ears.

I'm pretty sure I haven't heard the 10p before so I live in hope.
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#11 Re: more speaker porn

Post by ed »

completely neglected these after Owston so a couple of pics of the finished goods for those that didn't see or hear them:
mon single.jpg
and
mon pair.jpg
I've finally found some time to tune in the tweets but they're proving trixy...
I started with a 2nd order xover but couldn't get the level of the tweeter up to the Alpair with the l-pad...consequently scratching my head at the mo. As a contingency I've just got a cap in at the moment, but even that's proving problematic.
Last edited by ed on Wed Jul 18, 2018 9:03 pm, edited 2 times in total.
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#12 Re: more speaker porn

Post by ed »

here are the first attempts. There is a serious drop out at 6k on the Alpair. Although I didn't notice it when listening it is a tad worrying....
a10p-rbt95-individual.jpg
and
a10p-rbt95-both.jpg
should keep the subjectivists happy.
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#13 Re: more speaker porn

Post by ed »

I've just realised there is an error in the previous images.

The top image shows the tweeter contribution to be about 3db above reality. I hadn't calibrated the testing amp at that point. The bottom image showing the alpair and monacor together is correct.

I am really scratching my head here, Monacor say the rbt95 has spl of 98db, Klang and ton measured their units at 93db and I've measured mine at 88db.......so there's no way I can pad down an 88db tweeter to match a 90-91db alpair 10....I'd have to pad down the alpair, and that really isn't going to happen...

but, even slightly less efficient than the alpairs, the monacors are still contributing some useful stuff between 10k and 15k...so at the mo they are running with just a 1.5uf cap. The intro of the choke for the 2nd order filter was just too much for them.

onward
edit:

all calibrated and back in the real world....

the Monacor:
rbt95-spl-10k-1w1m.jpg
the monacor sweep:
rbt95-mls-cap-only.jpg
and the final sweep both drivers:
a10p-rbt95-both-back-open.jpg
there is a slight discrepancy between the combined and monacor only chart....I can only assume this may be caused by placing the mic between the two drivers for the combined plot, where as the monacor on it's own had the mic on axis. I'm still creeping up on this multi driver shenanigins.

now to spend some time listening...I'll leave the 1.5uf cap as is for the present, while I ponder what to do with the 6.5k drop out.....I wonder if this is just these drivers or whether it's all A10p'.
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#14 Re: more speaker porn

Post by Cressy Snr »

Interesting re the Monacor RBT-95 tweeter.
It works perfectly with the Fostex FF225WK drivers in my old Mets that Dave now has.
The Fostexes are supposed to be 93dB sensitive.
The 93dB, Klang & Ton have measured with the RBT-95, seems to corellate well with the ribbons
not requiring padding down on the big Mets.

That dip might be a cancellation effect, or it might not. Have you tried reversing the phase of the tweeter relative to the main driver? That might work out additive with the dip, to bring the response flat with both drivers playing.

It might bugger up everything else, but it's probably worth a try.
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#15 Re: more speaker porn

Post by simon »

I'm going to agree with Steve. I use the rectangular versions of the Monacors with 12Ps (which are supposed to be 91ish dB IIRC) and pad them down to match the 12Ps, so don't really understand why yours seem so inefficient.

I've only measured with my ears though.
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