It's all about compromise Thanks for all the info Brad, I might be asking you some stuff in the future lol

Ultimately you can't just arbitrarily adjust Cms without consequence even if it doesn't directly impact sensitivity. If you look at the BTL example I posted earlier, the Fs jumped by nearly a half octave when we halved Cms. So the engineer is going to have to balance Cms (and sensitivity) with the other performance goals for the driver.

This would be why no one t/s parameter can be relied on to determine woofer quality? Also why there's no "perfect" woofer?

Short answer because I'm tired; Pretty much.

It's all about compromise Thanks for all the info Brad, I might be asking you some stuff in the future lol

I'll try to help if I can

On ‎6‎/‎6‎/‎2010 at 8:45 PM, mrbojang said:

I was just reading the thread discussing running DVC subs off one coil compared to both and there was also talk of sub woofer efficiency...That got me thinking, what is the most efficient driver available for mobile audio applications? Also why is efficiency generally so bad? Given technological progress with computers, phones, etc you would think there would be great leaps in sound and driver efficiency also? Have drivers made progress over the past 20 years?

Pioneer TS-W1200PRO they are 105db I have a set

Woah, a 9 year pull.

And the Pioneer spec is BS.   

Just now, Tirefryr said:

And the Pioneer spec is BS.   

And sensitivity does NOT equal efficiency.

 

Nearly every driver ever made is less than 1% efficient.  What this means is for every 100 watts you feed the driver, 99 or more are simply transformed into heat.

On ‎6‎/‎6‎/‎2010 at 8:45 PM, mrbojang said:

I was just reading the thread discussing running DVC subs off one coil compared to both and there was also talk of sub woofer efficiency...That got me thinking, what is the most efficient driver available for mobile audio applications? Also why is efficiency generally so bad? Given technological progress with computers, phones, etc you would think there would be great leaps in sound and driver efficiency also? Have drivers made progress over the past 20 years?

subs in the 80s and  90s was higher db/spl then subs are now and companies said a lower bd sub will take more power and last longer. what they don't tell you is that it takes 4 or 6 of todays subs to be as loud as 2 old school subs. so the company makes more money by forcing you to buy more subs and bigger amps to get loud

They were not more efficient.  They simply catered to efficiency by designing drivers for larger enclosures.  Today, most everything is made for compact enclosures, and power is stupid cheap nowadays, so it's easy to throw a ton of power into an inefficient driver and application and get a lot of output.

Ah. I was reading about Phoenix Gold Cyclones just now..Can't seem to find an efficiency rating, although someone mentioned they probably are the most efficient.

4 hours ago, moosix said:

Ah. I was reading about Phoenix Gold Cyclones just now..Can't seem to find an efficiency rating, although someone mentioned they probably are the most efficient.

I believe they are out of production.

They did not last more than a few years and are nearly impossible to find.  They needed a minimum of 3 cubes and they were stupid big to begin with, so it necessitated an obscenely large (dimension wise) enclosure.  They WERE upwards of 3% efficient though and damn were they smooth!