Speaker sensitivity vs SQ

I've just thought of a new product:  A voice coil fan!! Gotta run patent it!

See you all in Colorado!!

Another area where attribution is difficult, the dynamic nature of high efficiency systems.

Is it that, or is it the controlled dispersion?

I'm not saying low compression speakers aren't good. I'm saying that some of what we may attribute to "fast" or high impact speakers is really just better room integration.

Amazing how you can take a slow, muddy, small sounding speaker and transform it with the appropriate room treatment, or how a poor room will sound better with tightly controlled speakers like horns, ESL's and open baffle.

So, this is the part I'm not clear on.

You can use DSP to deal with non-linear behavior in a driver which are constant.  You measure the output at say 90 db, and at 70 db, and you create transforms which adjust the output accordingly.

However, what I know of as thermal compression is not constant.  The driver has a thermal history and changes behavior accordingly. That is, as the driver gets hotter it no longer behaves the same way. To compensate for this you would need to have an algorithm which has an accurate thermo-acoustic model for the speaker AND knows the actual voltages applied.  That's a great deal of work vs. getting drivers which are thermally stable in their usable range.

Best,

E

Wait, did we just enter the "speakers should be made of wood, brass and silver because that's what musical instruments are made of" world?

The principles of measuring a good sounding room have been well documented for decades.  The measure of only using things that appear in nature is silly.  Does your drywall reflect any sort of natural space?? No, it does not.

If the room acoustics aren't removing the excess noise, then your brain is, and that's tiring.

Hoffman's rule applies to passive dynamic drivers in traditional cabinets.

I have found it interesting to see who has worked around some of this at times, including KEF, B&W and even Bose.

Some interesting designs using smaller than optimal cabinets, which fix the bass by EQ are fun to discuss.

Best,

E

Hence why I will harp incessantly w.r.t. acoustics and take with a grain of salt many audiophile claims, especially after seeing listening rooms. Totally laughable when they then make claims about other people's systems not being resolving enough. But I digress.

I'm with you.  What I think I have observed is

a - Self delusion
b - A large variability in the ear brain mechanism being able to filter out room acoustics.

Based on what I know about machine learning, and neural nets, and observations at shows, I believe some listeners can pick out some delicate traits about system despite absolutely terrible rooms.

I personally, cannot.  As studies in learning and acoustics have shown, filtering out noise is energy consuming.  Your brain works harder in an acoustically messy environment and I absolutely feel it.

That’s my understanding as well, but JBL...

@audiokinesis

Heh, I almost referenced JBL’s work in pro systems, as it’s among the most well documented and easy to find. Interesting 3rd way to skin this proverbial cat.

Also, I can’t type at all!

weather = whether

Also, while I believe it was Dr. Linkwitz, I cannot for sure remember, and I hope he doesn’t haunt me with bad crossover phase matching if I am mistaken in attribution. I do however remember the oscilloscope output very clearly. It was quite convincing.

While I do not need anywhere near JBL monitor style output, choosing tweeters with high power handling and very low measurable compression was a big goal for me.

I should point out that we should not attribute thermal compression to what might also be bad acoustics. Very reflective environments will have similar audible results, in at least as similar as you can type about them. A lot of bad / compressed treble complaints I’ve seen on audiogon were addressed with better room treatments. Was it excess reflection, or better treble/bass balance, or did the improvement in sound quality lead to turning down the knob, therefore reducing tweeter power dissipation? Really hard to say unless we are measuring. I sure could not explain in words how to hear a difference. :)

Best,

E

Everything that I’ve ever read about dynamic speakers agrees with Duke’s friend's observations.

Bigger voice coil, more ventilation, lower power dissipation result in lower dynamic compression. Of course, all things are not ever equal, but the difference in engineering speakers for professional, continuous high power use vs. consumer speakers is all out there to read. If you want to maintain high output you must control the heat, weather by reducing power dissipated or increasing ventilation or both.


@audiokinesis

@audiokinesis

A couple of years ago I read an article on compression in traditional dome tweeters.  I was 99% sure it was from the late, great Dr. Siegfried Linkwitz but now I can't find it.

Anyway, yeah, thermal compression happened supper fast.  First tone burst was normal, then by the second only the first couple of cycles were even close to the original output.

Well, color me surprised, again, that we are comparing insensitive speakers for sound quality.  I though this would be about efficiency and how high efficiency drivers, heating up less, were often less prone to thermal compression.

I'm not sure how we can correlate efficiency or sensitivity to sound quality if we are confounding the discussion with types of motors.

So what is the term for plain old lack of linearity of a driver?  That it's output at 90 dB doesn't match it's output at 70 dB? Is this considered strictly as mechanical compression?

Also, the best AMT's have amazing lack of such artifacts and incredibly robust power handling. :) One of the reason I'm a big fan.