I put the Alpair 10.2's in 8L sealed enclosures and was surprised by the bass extension for a 5.5".
The frequency response without any crossover components is as flat as I've ever seen for a fullrange, thanks to the built-in BSC. That said, the 8kHz and 10kHz breakup peaks were not seen in the official datasheets, and the Fs is 40Hz (after break-in) and not the advertized 36Hz. Since the other official T-S parameters are off as well, the box calculations still end up the same.
Harmonic distortion I measured to be very low. It sounds good, very good. Upper midrange clarity would be improved if crossed over to a tweeter at 2.2kHz LR2. To me, everything sounds better with a tweeter.
The frequency response without any crossover components is as flat as I've ever seen for a fullrange, thanks to the built-in BSC. That said, the 8kHz and 10kHz breakup peaks were not seen in the official datasheets, and the Fs is 40Hz (after break-in) and not the advertized 36Hz. Since the other official T-S parameters are off as well, the box calculations still end up the same.
Harmonic distortion I measured to be very low. It sounds good, very good. Upper midrange clarity would be improved if crossed over to a tweeter at 2.2kHz LR2. To me, everything sounds better with a tweeter.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Your have to remember that T/S parameters are curves notscalars. Typically us DIYers ar emeasuring in quite a different spot on the curves. That your numbers are soclose to the factory ismore an indication of how horizontal the MA T/S curves are --backed up by other's measures.
dave
Thanks! That is great info. I got some proper sized baffles cut, got a compass to draw the outlines for the circular holes. Now I just need to cut the holes, glue the two layers of the baffle together (to form the rebate for flush mounting the drivers) and glue them to my old B&W boxes. Maybe this weekend I'll do it...
But you've given me more reason to get to it. Thanks again for the data.
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But you've given me more reason to get to it. Thanks again for the data.
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Really? I see. I had always thought that factory specs were computer generated and not measured, due to them always being different from actual measurements.
Factory numbers are typically an average from a significant sample (Mark measures something like 8%) using LEAP or LMS. Tight drivers like Mark's will be +/-8-12%, Fostex as high as 18%, less tightly controlled, you take a guess.
More than once i have posted my measures of an FE127 -- far from factory -- and then Mark measured them with factory kit and got numbers essentially the same as factory. Fs of 75 vrs over 90 IIRC.Both sets of measures eqully valid.
dave
More than once i have posted my measures of an FE127 -- far from factory -- and then Mark measured them with factory kit and got numbers essentially the same as factory. Fs of 75 vrs over 90 IIRC.Both sets of measures eqully valid.
dave
After just 24 hours the difference is pretty stark, they really loosened up a lot in just a day. Not much bass sitting in a cardboard box, but man the detail and imaging is right on up there. And they have evened up, I thought they probably would.
I'll build some of these small boxes to run them and probably do a Pensile or whatever that large TL box is for these over the winter.
I'll build some of these small boxes to run them and probably do a Pensile or whatever that large TL box is for these over the winter.
Hi Guys,
Emil Askov in Europe has sent me details of his home built Alp10 small enclosure project using IKEA bowls (see pics). These bowls appear to be increasingly popular for smaller projects. I've not had any opportunity to listen to spheres, would be interesting to know if any members have any experience with smaller size projects like Emil's.
Cheers
Mark.
Emil Askov in Europe has sent me details of his home built Alp10 small enclosure project using IKEA bowls (see pics). These bowls appear to be increasingly popular for smaller projects. I've not had any opportunity to listen to spheres, would be interesting to know if any members have any experience with smaller size projects like Emil's.
Cheers
Mark.
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Well, it's time for Zombie Thread Return From The Dead.
I *finally* (!!) cut the holes for mounting my (now not so new) Alpair 10.2's in 8 liter cabs (salvaged from an ancient pair of B&W DM100). I lost patience and cut the baffle holes with a jig saw, using a blade for cutting curves. It ain't pretty like you other guys do it, but it seems to have worked. I'm in the break-in phase now. They've been playing the radio at a low volume for about 48 hours now. The sound keeps changing. It's crazy. When they were fresh out of the box, they sounded thin, no bass, honky mids. The next morning the highs began to come out. That afternoon they started to make a little bass. Last night they sounded fuzzy, but this morning they've cleared up. I can't wait for 100 hours to be over so I can play them in the main system at a moderate listening level.
Right now, it sounds like they might need some BSC. The mids are still too prominent. It could be my lousy cabinet work, or it could be a break in thing. I guess I won't know until I play them at moderate volume. The whole idea behind this model is that they should not need any BSC network, correct?
I have high hopes for these.
-=|=-
I *finally* (!!) cut the holes for mounting my (now not so new) Alpair 10.2's in 8 liter cabs (salvaged from an ancient pair of B&W DM100). I lost patience and cut the baffle holes with a jig saw, using a blade for cutting curves. It ain't pretty like you other guys do it, but it seems to have worked. I'm in the break-in phase now. They've been playing the radio at a low volume for about 48 hours now. The sound keeps changing. It's crazy. When they were fresh out of the box, they sounded thin, no bass, honky mids. The next morning the highs began to come out. That afternoon they started to make a little bass. Last night they sounded fuzzy, but this morning they've cleared up. I can't wait for 100 hours to be over so I can play them in the main system at a moderate listening level.
Right now, it sounds like they might need some BSC. The mids are still too prominent. It could be my lousy cabinet work, or it could be a break in thing. I guess I won't know until I play them at moderate volume. The whole idea behind this model is that they should not need any BSC network, correct?
I have high hopes for these.
-=|=-
Let me first say, I don,t know much about the inner workings of speakers I leave this to my son who has convinced me to build a few boxes. What I do know is furniture & cabinets, so my love for mdf or marine ply is very limited. Building a 6 sided solid wood box has many issues mainly the constant stress on the cross grain glue joints. In my neck of the woods that means that a typical 12” wide red oak plank or panel (for example) will move upwards of 5/16” as our average humidy changes from 6%-12% seasonally. My solution is to build top,bottom and sides of solid and use a sub strait for front and back.I hand cut my own veneer so what ever looks good I can use,the solid carcass on mine will be shedua. We just completed my sons alpair7 s , using one of the plans on marks sight.
Well its time for my pair, over the last number of years (to many to count) most of my listening comes from live music, artists from fusion jazz such as spyro gyra to Dave M &Tim R to Clapton unplugged to note a few. For the last number of years I have been using my “bought new in 1978 “AU417 sansui amp and a pair of energy rc-30 speakers. That amp now needs repair and I have a small 30watt topping chip amp, not quite big enough for its home in the large 600sq space. So with a sound card upgrade to the computer and a new 50ish watt amp I am thinking of buying the alpair10 or even 12s.
I am trying to get away from the cabinet grade look of a typical speaker(no offence intended) and incorporate them into more fine furniture grade stands, I guess you call it a pencil type box but a 36”to 38” tall box would be more appropriate to the design. So any input to speaker choice or cabinet dimensions would be appreciated .
Paul Burchell Woodworking
Well its time for my pair, over the last number of years (to many to count) most of my listening comes from live music, artists from fusion jazz such as spyro gyra to Dave M &Tim R to Clapton unplugged to note a few. For the last number of years I have been using my “bought new in 1978 “AU417 sansui amp and a pair of energy rc-30 speakers. That amp now needs repair and I have a small 30watt topping chip amp, not quite big enough for its home in the large 600sq space. So with a sound card upgrade to the computer and a new 50ish watt amp I am thinking of buying the alpair10 or even 12s.
I am trying to get away from the cabinet grade look of a typical speaker(no offence intended) and incorporate them into more fine furniture grade stands, I guess you call it a pencil type box but a 36”to 38” tall box would be more appropriate to the design. So any input to speaker choice or cabinet dimensions would be appreciated .
Paul Burchell Woodworking
The dims I found would suggest the boxes are closer to 14 liters.
The boxes are sealed right? You won't get the same bass extension as a vented box.
jeff
Well, I guess I goofed there. I measured 37cm x 22cm x 21cm external dimensions. Subtract 3cm from each dimension for cabinet wall thickness and I get 34 x 19 x 18 = 11.63 liters.
Oops!
Looks like I'd do much better with a 1.5" inside diameter vent, 5" long.
F3 for the 12L sealed box = 73Hz
F3 for the 12L vented box = 51Hz
Does that look about right?
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Sim shows a bit of a hump centered around 90Hz, so you could go a little longer if this is an issue. 7" long vent would flatten things out nicely if it fits in the box.
jeff
Hmm, that could be a problem. The box is just over 7.25" deep, internally.
What frequency did you tune the box to? About 37Hz?
I'm using WinISD, so it's probably not as accurate as what you're using.
Come to think of it, a bit of a bump around 90Hz wouldn't be such a horrible thing if I don't try to use them with subwoofers.
What frequency did you tune the box to? About 37Hz?
I'm using WinISD, so it's probably not as accurate as what you're using.
Come to think of it, a bit of a bump around 90Hz wouldn't be such a horrible thing if I don't try to use them with subwoofers.
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