Alpair 7.3 Heresy

[simon dart]

Having an impulsive streak on the back of adventures with Alpair 6P, I got myself some shiny new 7.3's. (Thanks to Mark for excellent customer service when I had a problem with the order, by the way)

I bodged a baffle for some cast off experimental 10litre sand filled enclosures to gain some impressions. Running them in it became apparent they do have quite remarkable resolution, but as anticipated are not the most flattering of poor source material/equipment.

In a bid to make the running in a little more tolerable and curiosity, I added some naked Eton ER4 AMT's which are currently looking for a home via a knock up capacitor-less AR-SXO. I tweaked values to cross over around 5kHz. The plot is on tweeter axis. (windowed don't take any notice of the low end)

Oh my, sometimes a happy accident can shift your whole perspective. This unplanned, collision of parts makes seriously good music. The resolution and harmonic integrity is just beautiful as long as you keep to moderate spl's. It retains all of the openness of the single driver with top to bottom coherency. Which leads me to a bigger question. Maybe the best thing to do with a full range is to run it multi-way?

[ultrakaz]

Hello, what are the crossover values? Thanks.

[buzzforb]

Dosen't the 7.3 have greater extension than your ribbon? I think you are right about the multi-way, just the other way.

[planet10]

Originally Posted by buzzforb

Dosen't the 7.3 have greater extension than your ribbon? I think you are right about the multi-way, just the other way.

+1

dave

[chrisb]

Originally Posted by buzzforb

Dosen't the 7.3 have greater extension than your ribbon? I think you are right about the multi-way, just the other way.

Originally Posted by planet10

+1

dave

+2 AFAIC, the top couple of octaves is not this driver's weakness; it has very few actually - not being a 1000w rated THX certified sub (joking), and the dimensions of the mounting flange make them tricky to flush rebate in thinner panels.

Active with stereo line level XO on 7.3 between 120-150 to your favorite woofer. There are a lot of very nice 6-8" units that would blend very well, including Mark's own EL166/ Woofer 6, or you could go for something bigger like 12-18" in H-frames.

[Andrewbee]

Maybe the best thing to do with a full range is to run it multi-way?

Perhaps not the "best" way but certainly imho one of the better compromises

I have found, by and large, releasing a F.R. driver from the responsibility of the bottom octave or two improves resolution and yes, we are now talking about a 2 way speaker.

The only Markaudio driver I have heard is my Alpair 6's, the original metal coned versions which are very nice. I have only played them full range however.

Having said all that, my favorite compromise is still using a F.R. driver full range. I have found when crossing over to a subwoofer or woofer I always find some integration issues but the issues varies with the music, perhaps the way it is mixed? I don't use a tweeter very often as my hearing is not what it used to be and as long as the midrange is right, I'm happy.

[silverhairbp]

In my humble and biased opinion, the more difficult range for a full range speaker, especially one with the hf extension of the 7.3, is the low frequency. Simon's design seems to build on the weakness of the 7.3 and eliminate its strengths.

Tell me you didn't REALLY put a choke on that 7.3.

[silverhairbp]

Originally Posted by chrisb

+2 AFAIC, the top couple of octaves is not this driver's weakness; it has very few actually - not being a 1000w rated THX certified sub (joking), and the dimensions of the mounting flange make them tricky to flush rebate in thinner panels.

Active with stereo line level XO on 7.3 between 120-150 to your favorite woofer. There are a lot of very nice 6-8" units that would blend very well, including Mark's own EL166/ Woofer 6, or you could go for something bigger like 12-18" in H-frames.

Actually, have a look at the Peerless 830667 8" woofer. Looks like it would be a good match for the 7.3, especially using a passive 1st order crossover at around 300hz - 400hz. Seems to model pretty well in a 1.0 to 1.5 cu ft sealed box or a small ported box.

[simon dart]

Well I thought that my little exploration might possibly raise a reaction, woo! Silverhairbp's overstating the case when he kindly refers to it as a "design."

I DO intend to FAST them, that's what I bought them for.

I was just messing around trying out the AR-SXO crossover topology for the first time, while breaking them in on my office system. (0.1mH, 8R2, 0.4mH btw Ultrakaz)

I think I should have made it clearer that my only point is: fool around sometimes good things happen that you don't expect.

[ultrakaz]

Hi Simon,

You were clear enough. You opted to share your favorable result/discovery, but were met with negative responses from those who have not even heard your implementation. Good grief(!), I'm a bit surprised by the responses. Why not cross the 7.3 to a tweeter? Perhaps, one doesn't like the treble coming off a 4" aluminum cone, notwithstanding beaming and/or breakup. Personally, I think the 7.3 would make an awesome mid where the driver is being used in its most effective pass band, or even a mid-woofer where shallow slopes could be used in a smallish box. Keep up the "heresy", and don't be afraid to go outside the lines with creativity.