Dynamic compression in speakers themselves?

http://www.ajaudio.co.uk/Loudspeaker%20thermal%20compression.htm   Thermal compression is a term used to describe the effect on a loudspeaker of the voice coil heating up during use.

@johnk

Thermal compression is one problem - affecting small voice coils much more than large ones. Small voice coils are standard for the consumer market because they are so much cheaper and easy to build as tolerances can be as sloppy as you like.

The other form of compression is from non-linear magnetic field. Long small diameter voice coils are cheap and have good sensitivity but the coil is not immersed in an even magnetic field - so harmonic distortion is high and they run out of linearity almost immediately upon any excursion.

I am sure that most folks here dismiss this problem...so I will include a link to a $30,000 lauded speaker that suffers heavily from compression. This is not an attack on Magico as I can do this for almost ALL high end consumer brands...

Look at the Deviation from Linearity plots - oh dear a cavernous hole in tweeter response - this means lots of distortion too as the crossover won’t work effectively as the tweeter impedance changes dramatically. A terrible design but all too common and almost all major high end brands (20,000+) tested by Sounstage show this weakness!!!!

http://www.soundstagenetwork.com/index.php?option=com_content&view=article&id=1043:nrc-

If anyone challenges me I can post dozens more links all with top speaker brands - all with dismal performance in this area. No wonder live music sounds so much more real and “live” compared to most high end consumer systems. These systems with these deficiencies just sound strained, dull and boomy when asked to produce live dynamic sound.

There is a very small following of folks with giant speakers ( Tannoys etc) that really get this essential aspect of fidelity. And the surprise is that you don’t have to actually listen very loud to hear the difference - just some well recorded dynamic music.

Indeed, the main difference between life music and what we get from our “hi-end audio equipment” to our ears are the dynamics, so what are we doing, firstly we often (including myself) use Compact Discs as the data carrier, and Geoffkait nailed it when he mentioned “If your source is CDs the odds are very good any particular CD is dynamically compressed, and not just a little bit as things have gotten a little bit out of control. If your source is LPs or even hi res downloads there has been some overly aggressive dynamic range compression going on there, too.”

Secondly, people love to use plenty “dynamics” traps in their rooms, which they call “bass-traps”, and finally, yes indeed, dynamics at louder levels will be compromised by the speakers’ abilities to produce such high peak sound pressure levels. Of course, the rest of the electronics do contribute a bit as well. Even cabling and power source may contribute, however we should start to make corrections in the proper sequence. Why worry about the loss of dynamics at the power source/cabling level, and not addressing or be picky when choosing Compact Discs (or even LP).

@mtrot --

To reiterate your initial inquiry a later clarification:

The primary audio characteristics I want to achieve in my system is an open, uncompressed, unstrained, and highly dynamic presentation. What I don’t know much about is how much speakers can or do contribute to loss of dynamics and impact. I have a very powerful amp, but it seems that when I increase the volume, yes, the speakers get louder, but perhaps not commensurate with the increase in the volume control. I do think I understand that this type of presentation is more easily achieved with larger scale speakers, but even with my large speakers, I feel something is wanting.

...

I guess I should clarify that I’m not looking for high SPL playback. I’m just looking for that big, relaxed, open, uncompressed sound. I want dynamic crescendos in classical music to get my attention, but with a sense of ease, if that makes any sense. Should I gather that I should be looking for high quality floor standing speakers with ~12 inch woofers and at least 96dB sensitivity?

It’s commendable that you’re able to articulate the above (not least the traits mentioned, per my own sonic priorities) as an actual bearing on where you want to go with the sound through your setup. Even though you’re not looking for "high SPL playback" per se it would be an inherent capability of speakers that conforms to your needs. Traits like ease, dynamic capabilities and a " big, relaxed, open, uncompressed sound" to my ears is very much grounded in the live, acoustic presentation, and even among audiophiles, very generally, I don’t find it a predominant sonic direction to be sought. One particular aspect that in a sense binds all of the above together (or is a cumulative product of it) is the sensation of ease, and really to be able to achieve this underappreciated quality you want "engines" much more powerful than what you strictly need, coupled no least with transient speed and a big air radiation area to fully load the room and give you the feel of size of scale to the sound. Sometimes you need to feel small when confronted with a sonic (re-)presentation, even startled by the sheer force and power - like witnessing (real) thunder and lightning, through which there’s also a deep emotional core to the experience; something is "ahead" of you here, and this way you’re better able to simply give in and concentrate on the on the whole of music (and not as a venture into dissecting the sound into bits and pieces as something happening "over there"). Sound reproduction, to my ears, is about being enveloped and carried away somehow, much more than sitting in a comfort zone and having an intellectual experience almost of something taking place at a distance. From my chair, going by your description above, the former is where I believe you at least implicitly want to be heading.

You then write the following:

Thanks much for all the great input here! I think, partly because of the expense and partly from an aesthetic standpoint, I’ll probably not seek to acquire the speakers mentioned here along the lines of ATC, PMC, Westlake, JBL, etc. The system for which I am investigating speakers is in our family room.

So, among more conventional dynamic floor standing speaker brands, any suggestions as to which of them might use the best quality components that would allow for the best dynamics of this "genre" of speakers? Which of them come closest to achieving my desired performance parameters? You know, just for starters, I’ll throw out names such as Sonus Faber, Paradigm, PSB, Monitor Audio, B&W, Legacy Audio, Daedalus Audio, Vandersteen, Goldenear, Revel, KEF, Dynaudio, Canton, etc.

Be careful not to shortchange your initial "quest" due to aesthetic requirements, though I’m aware both that and financial considerations can weigh in heavily in such matters. Better to take the time and find the right speakers and save up the extra amount of money potentially needed, and try and find an aesthetic solution that either doesn’t intrude too much in the family decor, or is so visually appealing that size and shape combine to be an actual asset - regardless of size ;) Many of the high efficiency designs fare very well when placed close to the wall behind them, so that their typically bigger size (and different shape) becomes less imposing compared to placing speakers way into the room.

The speaker brands mentioned in the second paragraph, save perhaps Daedalus Audio and Legacy Audio, are really what I’d consider "conventional" speakers that carries with them little if any of the desired traits pointed out by you. I would maintain the (active) ATC solution (minimum SCM100), and add Stage Accompany M57 and Volti Audio’s Rival and the more expensive models. I haven’t heard the Klipsch Heresy’s, but not too few here speak highly of them, and I imagine they’d do well with a pair of subs, as would the Klipsch La Scala’s (with subs). I’d seek out the new iterations of the Heritage line here. If you care to look into vintage horn speakers there are some great options here as well.