Does X-max = Spl

[uhoh_45]

theoretically, eveything else held constant (arguments sake, paper cone 12 inch subs, 300wrms, in a spec 1cube sealed box), a speaker with a sensitivity of 93 will be louder than a speaker with a sensitivity of 90. It *should* stay approx 3db ahead throughout it's acceptable power range, assuming the other speaker has the exact same power.

this means 1 of the 93db 12's is as loud as 2 of the 90db speakers, with the same signal applied

again though, this all goes to hell with different bl's, xmax's, power handeling, boxes, etc. assuming everything else constant higher sensitivity=higher volume, and 3db is basically a doubling of cone area or doubling of power, so the difference between the 83db of an HCCA and the 97db of a P1222 would theoretically mean that 1/16th the power is needed to get the P1222 to the same output as the HCCA

that just blew my mind

[Noobtastic14]

and a woofer with a higher sensitivity will reach its mechanical limits sooner than a lower sensitivity woofer.

whats better- 93db sensitivity with 500w or 85db sensitivity on 4000w ?

-Drew

[ptcary]

All this is good info, but I'm still confused (and I'm sorry if we are threadjacking the original poster on this).

For soemone like me who is basically done adding power to my subs, but would still consider upgrading subs in the future, I know that a sub with a more stout structure would be stronger, but I am VERY curious as to what a high sensitivity sub would do? I have read on SMD that some subs (Infinity for example) are not well accepted for SPL, but they rate high sensitivity, Powerbass is next, they do all right and are also high sensitivity.

You guys know I am a low budget builder, so Powerbass, DC Level 1 or 2 would be on my short list in the future, but I would never consider upgrading all 8 of my subs unless I could be pretty sure that I was gonna hear a noticeable difference.

[raytard]

the reason you dont see high sensitivity subs in spl applications is because they reach their limits faster

those infinity's may by 94db or whatever, but only up to like 200 watts

lower sensitivity speakers take more power, and actually get louder since a more effecient box can be used, and more power applied

basically, if you were going for something small and low powered, sensitivity is a nice thing, since a high sensitivity speaker on 200 watts could sound like a lower sensitivity one on 800

then again a good speaker in a good box with 800 watts will be head and shoulders louder than the good one on 200 watts

[Boon]

Just to fry everyone's noodle - in an SPL application you almost always burp at something very close to your box's tuned frequency.

At this point the subs excursion drops to almost 0 while the port air velocity spikes massively... so if you're only burping at your tuned frequency, you don't need much at all in the way of Xmax

[Stephen]

beat

[HHR Ed]

Just to fry everyone's noodle - in an SPL application you almost always burp at something very close to your box's tuned frequency.

At this point the subs excursion drops to almost 0 while the port air velocity spikes massively... so if you're only burping at your tuned frequency, you don't need much at all in the way of Xmax

Actually you would usually play 5 hz above box tuning.

Its more of the whole acoustical system tuning having to incorporate cabin volume, sympathetic vibration, material resonance, air mass, and other environmental conditions.

And I kind of said this in my post before, But yes, at frequency, the sub cone will travel its least amount.

This is because the wave is coupling at its greatest effciency to the air volume present on the front and rear of the cone.

You also have to consider power compression, which is when cone travel is limited by the amount of pressure being built up in the enclosure and cabin.

For SPL applications this is important to understand because then the most important specs of an SPL sub become motor force, Cone mass, and cone material.

[Torres]

oh dear lord...this is some good information floppin around here

[E a r t h]

Actually you would usually play 5 hz above box tuning.

Its more of the whole acoustical system tuning having to incorporate cabin volume, sympathetic vibration, material resonance, air mass, and other environmental conditions.

And I kind of said this in my post before, But yes, at frequency, the sub cone will travel its least amount.

This is because the wave is coupling at its greatest effciency to the air volume present on the front and rear of the cone.

You also have to consider power compression, which is when cone travel is limited by the amount of pressure being built up in the enclosure and cabin.

For SPL applications this is important to understand because then the most important specs of an SPL sub become motor force, Cone mass, and cone material.

http://www.stevemeadedesigns.com/board/public/style_emoticons/default/01nocomment8so.gif

[mr.p]

i can do over 150db with my lvl 4 xl's and they ARE BARELY moving at all, moving so little cooling is becoming an issue, versus my old box where they were nearing full excursion. i lost mby 1db just a guess because i didnt do a max spl run today; just saying, same everything just changing the enclosure, and the difference in xmax is not key its far more dependent on enclosure...if you have the right enclosure then in situations a woofer with more xmax and BL both could be that special combination, but high xmax probably wont compensate for low bl