Not really a fan of this terminology that goes around. This is pretty much a "car audio" issue imo. We don't have this problem in home or pro because we don't really try to break down woofers into stereotypical categories, so what I would to do is suggest a new set of terms that will help us better define and explain woofers! Seriously.

Previously, we have SQ vs. SPL.
SQ referring to woofers with good sound quality and SPL refereeing to woofers that just get loud. They are NOT mutually exclusive so this really doest work. In fact, as transducer engineer, I can tell you, I would argue that SPL actually is part of the sound quality definition - think of dynamic SPL range. In fact from my experience, the terms are more closely stereotyped with the brand or woofer name than the actually measurements. For example. DD woofers get loud and Focal woofers sound good. Or the W6 sounds better than a the W7. Really? Show me results. (I don't mean to call out any one or two brands here, they were just examples)

Then we have the hybrid term SQL - something that gets loud and sounds good -this seems be the mainstream marketing term now. Everything in one.

Then we have very more obscure terms like

SQE -Sound good to my ears only.

LSQ - Loud sound quality? I actually have no ideas what this one means.

None of them are wrong necessarily, but somewhat meaningless and inappropriate I'll argue. And the worst part about them is that they encourage stereotyping and don't allow the customer to appreciate the real differences of the designs. "If you have heard one SPL woofer you have heard them all" - for example.

Anyway, I would really like to decouple the psychology and opinions from the physics and engineering. A customer might be more inclined to like the previous convention, but I can promise you what I propose next is a complete breakdown of every woofer every designed that I know of… that is a lot!

Now, some of you know me, in case you didn't, I wrote bit about Myth's at Audiopulse.com. - a non-technical explanation to the average customer to prevent them from making stereotyping pitfalls about a driver! I soon hope to a formal study on system alignments and the psychology behind them (ported vs. sealed etc etc). I'll certainly back that up with testing but for now here is my new proposed convention, I'm posting it here (audiojunkies.com) so I can get some feedback and discussion about it. I'm not going to proclaim I know everything or that I am right so if you want to disagree, just support your argument, we might get an interesting thread here!

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Non-Linear

Average stuff... long overhung coils, good sensitivity, ok linearity. These are also good candidates for sensing coils. Most woofers fit into this category!

Anti-Linear

slightly overhung coils... basically all your SPL type woofers
Also pro audio woofers might be classified here if they have low xmax. they are after sensitivity because power is the bottle neck. There are also some oddities that fit such as anti-linear motors like JBL Differential driver and a few of the red rocks designs would fit into here. The key here is lower xmax, but higher sensitivity.

Linear

The stuff we talk a lot about, LMS, XBL^2 , MMAG, Dual Tandem Coil (Velodyne) about also people forget underhung is exceptional linear and should be lumped in to this category. Linear often has the highest xmax and lowest sensitivity.

There is also some other stuff that can be employed with the woofer such as accelerometers and active EQ, but I would consider that one step decoupled from the motor and they can indeed span any of the categories.

having said all that. you can break any rules you want. You can have a high sensitivity linear design with low xmax (think of Aura), or you can have a low sensitivity anti-linear design with higher xmax. Its VERY VERY important as a customer to understand not one category or design is better than the next... merely different. I would argue they all that their purposes, benefits and drawbacks.

This way a breaking down the drivers is merely my convention and mine alone, i dont expect anyone to use it, but hey... i think it's a little more meaningful than tag's like SPL vs SQ

Also want to propose, we can look at the inverse of this too and call them:

Non-Sensitive (non-linear)

Sensitive (anti-linear)

Anti-Sensitive (linear)


"Anti" is not a bad thing, i want to point that out, its just a reference point. And you can make designs that break the rule, but are still formally defined into a category. For example, a super high B linear motor is still an anti-sensitive design, but it might make it up in added cost for extra magnetism example. Many more examples exist. - Make up your own!

referring

damn... where is my edit button!

We are working on it. Some other stuff came up that delayed it, but I'll have it up soon.

Hrmmm, true, but getting the masses (especially the car audio masses) to adopt such acronyms is going to be difficult. Just take a look at Neil's attempt at changing "subsonic" to "infrasonic". Technically he is correct but it probably won't catch on with all teh intrawebzor peepz. ;)

Good luck though! :)