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Old 7th October 2008, 10:37 PM   #1
Chris74 is offline Chris74  United States
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Default Alpair 5 project completed

Hello everyone,

I'd like to share my experiences with this project which was based on the design suggested on Mark Audio's website. It uses the Alpair 5 wide range drivers with the CSS SDX7 mid/woofers. I realize this is a 2-way but since the Alpair 5 is a wide range driver (similar to certain EJ Jordan's) I thought I would post it in the full range forum so everyone could have a peek.

The crossover is a simple 1st order Butterworth (plus a 4 ohm resistor) crossed at roughly 300Hz. I am currently experimenting with different crossover values in hopes to optimize this design. Sound so far is quite good.

The enclosures used are the excellent Parts Express 1ft.3 MDF boxes with the gloss black finish and removable front baffles. I have been using various Clarity Cap, Goertz and Duelund crossover components. My experience thus far in the hobby of speaker building has been entirely novice so, from a technical aspect my knowledge of crossovers and loudspeaker design is certainly limited to say the least.

Throughout the years I have been fortunate enough to use and enjoy many different production and DIY loudspeakers (both dynamic and planer). I believe this latest DIY effort has been one the better performing loudspeakers I have had the opportunity to spend time with to date. Many thanks to all the guys here at DIY audio for giving me various insights and perspectives on loudspeaker building, these forums are an incredible resource for hobbyists such as myself. Lastly, just thought I'd mention to you guys that the Mark Audio team have been prompt and helpful in regards to communication and tech support. Well, I think thats a wrap for now........

http://s478.photobucket.com/albums/rr146/thorty40/

Cheers,
Chris
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Old 8th October 2008, 05:34 AM   #2
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Hi Chris,
They turned out really well, eh!
I must say I'm curious about these Alpair as they have a lower price than Jordans. Looking forward to your opinion.

Peter
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Old 8th October 2008, 07:16 PM   #3
chrisb is offline chrisb  Canada
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Quote:
Originally posted by peterbrorsson
Hi Chris,
They turned out really well, eh!
I must say I'm curious about these Alpair as they have a lower price than Jordans. Looking forward to your opinion.

Peter

yes indeed, it would be interesting to hear from anyone with experience with both the latest version of "official" Jordans (as in from the recent group buy) and the similar Mark Audio drivers.

Presumably there would be at least one enclosure design flexible enough to accommodate reasonable comparison between the drivers themselves - i.e. without being so finely tuned to the actual measures T/S parameters of either that the other was at a disadvantage.

My only experience with recent models has been with the Alpair 5 and the J6T in a little DIY 2Way by our friend Greg the Geek.

Aside from the captive lead-out wires on at least this pair of J6T, and the possible minor difference resulting from the extra coating layer to achieve the finish color(s) on the Alpairs, these appear to the exactly the same driver. Unfortunately, the Jordan drivers had received an EnABL treatment, while the Alpairs had not, so direct comparison was not possible. Indeed, the untreated Alpairs seemed to have a subjective advantage in terms of "air" and "detail", but without measurements, that could be indicative of something other than accuracy.

We will each of course read whatever we want into the similarities / differences between the larger drivers now offered with these two different brandings, but suffice to say that since the Jordan name was sold several years back, it should come as no surprise if the company and products take a different direction than Ted might have envisioned.
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Old 8th October 2008, 09:06 PM   #4
Chris74 is offline Chris74  United States
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Soon, I will have a much better idea of how this Alpair 5 / SDX7 kit will compare with the Jordan JX92s / Aurum Cantus (Jim Griffin) design as I am working on completing the MLTL 48 enclosures and crossovers right now. I'll post my impressions once I'm finished.
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Old 9th October 2008, 01:58 AM   #5
Chris74 is offline Chris74  United States
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Quote:
I must say I'm curious about these Alpair as they have a lower price than Jordans. Looking forward to your opinion.
Peter, I just wanted to mention that I have never heard the smaller Jordans so I really cannot comment about the sonic differences between the Alpair 5 and the J series drivers.
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Old 9th October 2008, 02:21 AM   #6
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Quote:
Originally posted by chrisb
Alpair 5 and the J6T... the captive lead-out wires on at least this pair of J6T, and the possible minor difference resulting from the extra coating layer to achieve the finish color(s) on the Alpairs, these appear to the exactly the same driver
Other than the above mentioned changes they are the same driver. Mark Audio developed some toolng for a number of Jordans, and with Ted selling to the Swedes instead of Mark Audio as had been planned, Mark Audio was left with everything in place to indroduce their own drivers (which in another reality would have been Jordans) -- I am very interested in the largest drivers.

ChrisB, we do have a pair of unmodified J6T. Comparison is easy.

I've not yet had a chance to compare any of the J6T (EnABLed/not & the Alpair 5), but we did compare the stock J6T to the FF85KeN. One of the nice things about the aluminium cones is that careful application of ethanol can reverse the EnABL.

We have ongoing projects mating both of these with various woofers (next up is an MTM with the Silver Flute 5") .

Chrisy74,

1/ what XO value did you use? A similar passive XO should be useable in Tysen (our active SDX7 + FF85 box -- originally sketched for use with Alpair)

2/ did you do the basic coating mods to the SDX7?

3/those curved PE boxes are really good value, much, much better than their rectangular ones. The very small surface area of the MDF panels and use of MDF plywood for the curved sides makes quite a decent box. On ours we will be replacing the baffles with ply. Do be careful thou, i have found that the cabinet walls can loose chunks if hit just right.

dave
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Old 9th October 2008, 02:37 AM   #7
Chris74 is offline Chris74  United States
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Quote:
Chrisy74, 1/ what XO value did you use? A similar passive XO should be useable in Tysen (our active SDX7 + FF85 box -- originally sketched for use with Alpair) 2/ did you do the basic coating mods to the SDX7?
Dave,

1) the original values up top were 4 ohm/15w resistor + 60uf caps, followed by a 3.0 mh inductor on the bottom. This gave me an approx 300hz roll off on top but have since increased cap value, lowered inductor and resistor value to move the xover point higher to take some of the workload off the Alpair 5's.

2) I am not familiar with the basic coating mods for the SDX7, can you please explain?


Quote:
One of the nice things about the aluminium cones is that careful application of ethanol can reverse the EnABL.
Can you also explain this process and resulting effects? Does this apply specifically to the Alpair 5 driver?

Cheers,
Chris
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Old 9th October 2008, 03:49 AM   #8
maxro is offline maxro  Canada
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Quote:
Originally posted by Chris74
Can you also explain this process and resulting effects? Does this apply specifically to the Alpair 5 driver?
Be careful what you wish for...
Enabl thread
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Old 9th October 2008, 05:22 AM   #9
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Quote:
Originally posted by Chris74
1) the original values up top were 4 ohm/15w resistor + 60uf caps, followed by a 3.0 mh inductor on the bottom. This gave me an approx 300hz roll off on top but have since increased cap value, lowered inductor and resistor value to move the xover point higher to take some of the workload off the Alpair 5's.
increased cap value will decrease the Alpair's XO point

Quote:
2) I am not familiar with the basic coating mods for the SDX7, can you please explain?
1st run you finger over the SDX7 cone with your ear close... then your fingernail. That ugly sound you hear has to affect the midrange of the SDX7.

Basic mod is 3-5 coats* of thinned modpodge (puzzlecoat). Each coat requires less material. You have to be very careful and hold the driver with the cone such that when you apply the puzzlecoat it will run away from the phase plug... if you don't take care you can get the stuff in the voice coil gap. Since the stuff is glue you don't want that.

*depends how thinned it is. When the nasty noise is gone/mostly gone you are OK

I'm hoping that the next batch Bob gets has this done at the factory

Quote:
Can you also explain this process and resulting effects? Does this apply specifically to the Alpair 5 driver
At this point reports are that the treatment as applied does not help -- i may have just got carried away... i have to do some listening and some experimentation. All my SDX7 i EnABL over top of the treatment described above.

dave
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Old 9th October 2008, 06:10 AM   #10
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Quote:
Originally posted by planet10
Other than the above mentioned changes they are the same driver. Mark Audio developed some toolng for a number of Jordans, and with Ted selling to the Swedes instead of Mark Audio as had been planned, Mark Audio was left with everything in place to indroduce their own drivers (which in another reality would have been Jordans) -- I am very interested in the largest drivers.
I stand corrected on some of this -- here is a podt by Bob Reimer that covers things off.

http://www.diyaudio.com/forums/showt...73#post1627873

dave
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