Aura Sound NS6-255-8A Testing

[erinh]

Been a while since I've tested anything, but I've had this Aura Sound NS6-255-8A sitting on my bench for a couple months now and figured I'd throw it on the baffle and run it through some Dayton testing gear as opposed to running the Klippel on it as that's a bit more involved. Though, if you guys are interested, I may try to put the Klippel LSI on it to see what the motor and suspension look like.


Here's the impedance sweep results:




The below is FR measured at 2.83v/1m, 0, 15, 30, 45, and 60 degrees with the accompanying polar. You can see I stitched NF and FF at approximately 400hz, as this is where they lined up best for all axes. My on-axis impulse is reflection free out to about 7ms so I ran up to that point, but still merged at 400hz. These are smoothed to 1/12 octave.







FR seems usable to about 3.5khz before the response gets pretty ragged. Also, looking at the impedance vs the FR, you can see a bump in impedance just before and after 4khz with a correlating bump in FR (and the same dip at 4khz in both). Honestly, I was expecting the bump in impedance to result in a dip in FR due to resonance . I'd like to hear what you guys think may be going on here. At approximately 5khz, the cone's modal issues crop up.

If I can find the time tonight, I'll try to run some IMD and HD tests on the drive unit as well.

- Erin

[erinh]

some more info...

HD at 90dB/1m equivalent:





HD with a single tone in the spectrum view (I did this to verify the high odd order distortion seen above):




IMD at 90dB/1m:




IMD at 96dB/1m:





Note: IMD tones were 0dB at 55hz and -6dB at 440hz.

What you see in the above is a generally high odd-order distortion component. From the HD plots, to be below 3% at 90dB, these need to be played above 70hz. Though, that single number is somewhat fooling because there's a decent bit of THD throughout the driver as whole, with the midrange (200-1khz) being the cleanest portion under 1%. Outside of this, THD is above 1%. Comparing the IMD at 90dB vs IMD at 96dB, you can see the odd order distortion creeping up on the even order distortion. Given that 30dB down from the fundamental is the 3% distortion mark, you can see that at 96dB, the odd order distortion is above this value.

[Hillbilly SQ]

Thanks for testing this driver. I still haven't had time to throw mine in to try out. With the distortion these things have would you consider it pleasurable sounding or nasty sounding? I tend to like a little bit of distortion for a soothing effect but not so much it causes fatigue. I would probably be crossing them steep at 100hz.

[chad]

I will attest to them not liking o be crossed low, mine are at 80. I tried lower and it was not that I got BAD results but rather NO results Could have been the door but other drivers did not have the issue. It's just not a very big driver.

[chad]

Thanks for testing this driver. I still haven't had time to throw mine in to try out. With the distortion these things have would you consider it pleasurable sounding or nasty sounding? I tend to like a little bit of distortion for a soothing effect but not so much it causes fatigue. I would probably be crossing them steep at 100hz.

Even order distortion is much more pleasurable, if you are into that.