Maybe I missed it but what is the mic distance, test signal, frequency resolution, smoothing, windowing, driver mounting?
And again, I believe it's important to look at all angles and not just 0°-30°. The walls in our rooms care about other angles too
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No smoothing AFAIK, likely 1m mic distance since that would be far-field for a 4" driver (ref Toole: measurements need to be taken in the farfield and scaled to 1m distance), driver mounted in an IEC box, with thin aluminum baffle. Taken with LEAP i believe.
Measures ideally go out to at least 90 degrees, but still this is better than just on-axis.
Go over to the Mark Audio forum and ask him for details.
dave
Measures ideally go out to at least 90 degrees, but still this is better than just on-axis.
Go over to the Mark Audio forum and ask him for details.
dave
Here is the off axis of the EL70.
Take a look at the bunching happening at 5khz. People who know more about driver mechanics than I do could say, but I think this is indicative of the first signs of cone breakup. The phase is changing from the outside of the cone relative to the inside. It may also be related to moving the treble onto the dustcap. Either way, that spreadat 3khz followed by gathering at 5khz would technically be considered bad.
Despite this, you can see that it has uniform dipersion up to the top octave out to 45d. It resembles the alp7. This is a Mark Audio built driver, and some here (Dave?) may be able to tell you if it's similar to the alp7 cone. I believe the alp7 cone is superior because it's a later gen product, and my ears tell me it is
EDIT - note my measurements are on a 5db scale and Mark's are 10db, just so it isn't confused. They're actually fairly similar (trends).
Take a look at the bunching happening at 5khz. People who know more about driver mechanics than I do could say, but I think this is indicative of the first signs of cone breakup. The phase is changing from the outside of the cone relative to the inside. It may also be related to moving the treble onto the dustcap. Either way, that spreadat 3khz followed by gathering at 5khz would technically be considered bad.
Despite this, you can see that it has uniform dipersion up to the top octave out to 45d. It resembles the alp7. This is a Mark Audio built driver, and some here (Dave?) may be able to tell you if it's similar to the alp7 cone. I believe the alp7 cone is superior because it's a later gen product, and my ears tell me it is
EDIT - note my measurements are on a 5db scale and Mark's are 10db, just so it isn't confused. They're actually fairly similar (trends).
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Many do. The big advantage in DIY is we can measure in OUR box, our baffle etc. I only worry about 15 degrees. because I know how I am going to use my speakers.
This is a nice one:
dave
Here's the Alpair 7.3 in a 43x43cm box from 0° to 90°:
(90cm mic distance, gated at 4,7ms)
Looks like a totally different driver.
Here's 0°-90° - pretty ugly:
Attachments
as in this particular sample is defective? or that your measurement don't align with those of the manufacturer's, whose measurement equipment is certainly adequate, and the many hundreds of satisfied owners of Alpair7s must all be failing to hear those issues?
Granted there are some folks who prefer other drivers, but few I think who've heard them would categorically state " (it) isn't good"
I feel it is worth pointing out here that manufactures specs/measurements often deviate significantly from those done by third parties, either for the better or for the worse.
If the driver isn't defective, if the mic is calibrated (or even if it's not, usually small condensor mics only display either a lift or a droop in the top octave, certainly nothing like this) and if the measurements were performed in a suitable enclosure/environment with suitable gating, then this is how they will measure. Break-in wont change that by much and if it does I'll eat my hat.
All that said, if you compare Markus' measurements to the MarkAudio ones they are roughly concordant with one another.
Markus' measurement - narrow dip at 1800Hz.
MarkAudio's - dip present.
Markus' measurement - peak at ~6k.
MarkAudio's - peak at ~6k.
Markus' measurement - peak/dip/peak at 10/12/14k
MarkAudio's - peak/dip/peak at 10/12/14k.
With all the issues getting less pronounced as one goes off axis.
The only difference is that MarkAudio's measurements seem less severe, ie could be smoothed a little and the huge dip at 400Hz isn't there in Markus' measurements.
The human ear tends to be quite forgiving of very narrow dips or peaks though (unless are room modes), especially ones in the top octave, so the fact that lots of people like how they sound isn't a surprise.
I've got a pair of Visaton BF45 full rangers that peak/dip/peak like crazy in the top two octaves, but sound wonderful by comparison.
If the driver isn't defective, if the mic is calibrated (or even if it's not, usually small condensor mics only display either a lift or a droop in the top octave, certainly nothing like this) and if the measurements were performed in a suitable enclosure/environment with suitable gating, then this is how they will measure. Break-in wont change that by much and if it does I'll eat my hat.
All that said, if you compare Markus' measurements to the MarkAudio ones they are roughly concordant with one another.
Markus' measurement - narrow dip at 1800Hz.
MarkAudio's - dip present.
Markus' measurement - peak at ~6k.
MarkAudio's - peak at ~6k.
Markus' measurement - peak/dip/peak at 10/12/14k
MarkAudio's - peak/dip/peak at 10/12/14k.
With all the issues getting less pronounced as one goes off axis.
The only difference is that MarkAudio's measurements seem less severe, ie could be smoothed a little and the huge dip at 400Hz isn't there in Markus' measurements.
The human ear tends to be quite forgiving of very narrow dips or peaks though (unless are room modes), especially ones in the top octave, so the fact that lots of people like how they sound isn't a surprise.
I've got a pair of Visaton BF45 full rangers that peak/dip/peak like crazy in the top two octaves, but sound wonderful by comparison.
I would like to echo 5th Element. Once you account for the difference in scales, the two runs are pretty much the same. At 60-90*, there is so much chance of getting defraction and reflections, even with strong gating. If you want to measure what you hear, step back and that some measurements a 2-3m.
Bob
Bob
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