[bjs]

I've been searching the 'net looking for actual tests of these drivers. Ilkka has tested an early version of the SDX15 but not the current versions. Beyond that I can't find any tests anywhere for either driver. I'm looking for real world distortion, power compression, frequency response etc. Can anyone point me to such tests?

 

[Mike P.]

I'm not aware of anything recent.

 

[bjs]

Yes, I've given up looking. Couldn't find anything at all. Tried asking the vendors for info but no joy there either.

I'm guessing the Tempest-X2 has similar "real life" frequency peak and distortion profiles as the SDX15. The designs seem similar. Of couse without any measurement data who really knows. :huh:

Be nice if people measured their builds as part of the standard process. :T

 

[fredk]

Be nice if people measured their builds as part of the standard process. :T

Unless you can measure outdoors and you have appropriate equipment those measurements won't tell you much about the driver itself.

There is a DIY site that owns a klippel, but they have not had anybody to run it for over a year. Hopefully they will start measureing drivers again at some point.

 

[bjs]

Of course it's a system measurement but that captures everything we need to know. Most of it can be done indoors and doesn't take anything more than a professionally calibrated microphone and REW.

The biggest issue I see is having sufficient technical knowledge to get good data but that's solvable with forums like HTS.

Maybe it's not practical, but I still think it would be cool if people did more of it.

 

[Kevin Haskins]

I'd be willing to conduct a subwoofer measurement day but it would require built units actually be sent to me in the Spring/Summer because all the measurements have to be done in the parking lot.

BTW: The only thing about the Tempest & SDX that is the same, is the fact that they are both 15" drivers with an XBL^2 motor. The motor technology only modifies the BL curve. It won't have any impact on the FR of the transducer, either good or bad. It will change high-level operation. When built right, it should lower non-linear distortion due to motor BL changes and all the T/S parameters that change with BL become more stable since the BL isn't changing with stroke. Either way... just because two drivers use an overhung or underhung motor, people don't lump them all together in the same category. I'm not sure why XBL^2 drivers get lumped either.... but I digress.

 

[fredk]

Of course it's a system measurement but that captures everything we need to know.

I took your first post to mean that you specifically wanted driver measurements. to me the most useful measurements if you want to compare two drivers would be raw driver measurements or comparisons in the same enclosure type: apples to apples.

For instance if you were to compare a sealed SDX design to a ported Tempest-X2, the Tempest would have an automatic advantage because of he distortion a sealed box can introduce and because of port/box efficiencies.