JBL M2 for The Poors

While I am at it... if anyone happens to live near the Huntsville, Alabama area and has a JBL 4367 you'd be willing to loan for a week or two for testing... let me know. I'm trying to get a pair in for review but so far the only willing participants are either in New York or Florida.
 
So... let's look at some data.
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YES!

You might be the first person to really *get* the point I am trying to make in that data. I think it is much more useful than the run-of-the-mill distortion graphics. Frequency response deviations - whether due to compression/enhancement or simply by DSP limiting - are what I call "nonlinear-linear distortion". 😀

So, thank you for taking the time to understand the graphics and use them to make meaningful comparisons.
 
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FR nonlinearity itself is termed "linear distortion" and is considered as not changing with increased output. Which, as my tests show, is not really always the case.

nonlinear distortion is distortion that happens as output is increased.

Since the FR change is a function of volume but impacts FR, I was making a joke that is a nonlinear linear distortion. 😉
 
Well, it is actually something inbetween. When you alter the gain over time (what termal compression actually is) while a signal is applied there is inded spectral content created that was not there before. Taking the rather slow change into account the new content is very low in level and the spectral lines are very close to existing ones and might therefore be completely masked.

Regards

Charles
 
Thank you Erin for this test!

Your power compression tests are opening a new window in loudspeaker comparisons. Eg. NRC test has too low spl for modern hifi speakers, but now we can see rather drastic differencies, that are also audible.
 
On speakers like the M2, I could bump that up. I set 102dB as the limit for my tests because I didn't want to risk blowing up smaller speakers. The smaller speakers are the reason I do this test, really because they are the ones I really want to "make a point" of.

But, sure, in the future I'll try to do some additional output testing where I feel it is safe to do so (and if I remember).
 
I’ll post it tomorrow. I tend not to bother because it can be seen in the SPIN data. Toole himself has a good quote in his book about how CSD isn’t anymore useful than off-axis response data. And I agree. It’s easy to spot in the CEA 2034 dataset when the graphs all jump up. You can see it as well by looking at the DI when it breaks the trend line and goes down toward 0 (as the sound/resonance is radiated omnidirectional). It’s also easy to spot in the normalized contour plots. I try to avoid having too many plots so I can save on bandwidth and server space costs. But .. like I said, I’ll post it tomorrow.

I dont know how to interpret time based information via off axis data to be honest...if a speaker rings like a bell at 250hz and doesn't hit -25db until 6 seconds....where do I look in the spin data to interpret this? At least this is why I depend on CSD and Burst Decay