SL's test of NEO3

[gainphile]

This is quite an insight on how SL test his drivers. Apparently he drives them to 30v vpp.

Triggered burst measurements of tweeters

There is an example of comparison between Seas 25TFFC and Neo3 and how they differ in such application.

I know some would argue that these are not audible, but surely if the objective is accuracy then the transducer needs to faithfully reproduce the input signals?

Then of course above all things the "wallet factor"

[StigErik]

It would be interesting if SL would do the same measurements at a frequency the Neo3 actually can handle.... like 3 kHz. We who have used this driver knows its no good below 2.5 kHz or so. The power compression loss seen should be the same though.

30V p-p is A LOT for a tweeter, very tough test this is.

[john k...]

Originally Posted by StigErik

It would be interesting if SL would do the same measurements at a frequency the Neo3 actually can handle.... like 3 kHz. We who have used this driver knows its no good below 2.5 kHz or so. The power compression loss seen should be the same though.

30V p-p is A LOT for a tweeter, very tough test this is.

I just refrained from posting the same thing. Here is my though: I don't place much credence on tests done w/o the intended crossover in place.

[gainphile]

Apparently SL likes to cross tweeters very low. 1440 hz for Phoenix and Orion and 1khz for pluto.

"The large amount of distortion at relatively low power level would rule out this driver for my applications, which usually require a low crossover frequency."

GR-Research is quoting usable xo point of 2khz and 1khz for monopole or dipole repectively: http://gr-research.com/pdf/NEO3.pdf

Zaph mentioned about the ribbons/planar only usable 2.5khz and above: Zaph|Audio

[JamesTRexx]

His point was that he didn't want to test its distortion using the best crossover point for the driver, but at the crossover point that he requires for his application, hence the low frequency.
That's what he stated at the end of that section.

Edit: Just too late to point it out first.

[john k...]

Originally Posted by gainphile

Apparently SL likes to cross tweeters very low. 1440 hz for Phoenix and Orion and 1khz for pluto.

"The large amount of distortion at relatively low power level would rule out this driver for my applications, which usually require a low crossover frequency."

GR-Research is quoting usable xo point of 2khz and 1khz for monopole or dipole repectively: http://gr-research.com/pdf/NEO3.pdf

Zaph mentioned about the ribbons/planar only usable 2.5khz and above: Zaph|Audio

Yes, SL uses 1440 Hz because that is as far as he can push the 8" midwoofer. The problem with the low crossover is also that the tweeter is pretty omni there so w/o a rear tweeter the polar response really balloons off axis. A rear tweeter helps, but has other problems. A higher x-o point (as I use in the NaO) helps more. But I am taking a different tack on improving the polar response of dipoles at higher frequency. Here are some results I just took today. The polar plots are constructed form measurements taken at every 5 degrees. I repeat, these are measurement, not simulations. The crossover point is 1200 Hz. The frequency for the polar plot is noted at the top of each figure.

[gainphile]

The NAOs uses 2x 6.5" drivers, my assumption to reach certain target SPL? By doing this the baffle can be narrower (as supposed to 8") and hence the tweeter xo can be higher. At what frequency do you cross the tweeters in your design if I may ask?

Higher tweeter frequency is definitely desired as not everyone can afford $300 (times four) Millienium tweeters.

What is this "new approach" that you're working on re: tweeter polar response.

[cuibono]

Hmmm, all very interesting. Very interesting. I hope JohnK will share more.

I've been using the Neo3PDR crossed at 1700 LR4 acoustically. Personally, I like it a lot. I hear nothing I consider a problem yet. Of course, maybe I need more outside references...

To bad SL has already ruled it out - it seems like a decent driver to me. Maybe his test is a little harsh?

[villastrangiato]

Looks like an apples and oranges comparison.

http://www.seas.no/images/stories/vi...519_25tffc.pdf


http://www.radiapro.net/uploads/NEO3WhitePaper.pdf


Wonder if Sig looks at the 20 Watt vs. 80 Watt input power and 3.5 vs. 6 ohm nominal impedance before comparing the Lincoln Town Car to a Greyhound bus. Maybe his philosophy goes something like: test first - read specifications later......

[ucla88]

Originally Posted by john k...

Yes, SL uses 1440 Hz because that is as far as he can push the 8" midwoofer. The problem with the low crossover is also that the tweeter is pretty omni there so w/o a rear tweeter the polar response really balloons off axis. A rear tweeter helps, but has other problems. A higher x-o point (as I use in the NaO) helps more. But I am taking a different tack on improving the polar response of dipoles at higher frequency. Here are some results I just took today. The polar plots are constructed form measurements taken at every 5 degrees. I repeat, these are measurement, not simulations. The crossover point is 1200 Hz. The frequency for the polar plot is noted at the top of each figure.

Hey John, how are you doing that? I've been toying with a waveguide on my dipole baffle hoping to achieve a bit more directivity.

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