Does sub sensitivity matter?

[thehoe92]

A speaker's total power rating should not be confused with the power required to drive the speaker. The output of a speaker is based on the sensitivity rating. Power from the amp goes into the speaker one watt at a time. This is the same for all amps and speakers. The SPL of a speaker starts at its sensitivity rating i.e., say 94 decibels at 1 watt of input power. When power is doubled, SPL goes up a theoretical 3 decibels, so 2 watts = 97dB, 4watts =100dB, etc, till roughly 1000 watts yields about a 30dB increase in SPL. The driver with a sensitivity of 94dB will yield about 124dB of output at 1000 watts. This is in an open environment and excludes boundary, box and transfer function gains inherent in vehicle interiors. Digital Designs speakers are designed for both high sensitivity and high power handling. The higher the sensitivity rating, the higher the amp/speaker combo could SPL. If a 300-watt amp is used, the speaker with a higher sensitivity will potentially yield the highest output regardless of its total power capability. There are many other factors that govern output capability, but total power handling is not a significant one and should not be the main criteria in the selection process.

[JZeFF]

And then...

A kappa perfect 12 with dual 4ohm voice coils has a sensitivity of 92db..

A moving air mass of 189.8g..

The dc lvl 4 has a moving air mass of 173.08 and 87db..

Put an infinity in a t-line box built specifically for that sub..

do the same for a DC lvl 4 in a t-line..

which one is the better sub?

I just dont get what makes the DC or the FI, or the DD..a better sub than an infinity..

I understand they can take waaaay more than rated power.. but why is that an advantage to me.. a daily driver?

Im not trying to bash anything.. so dont even go there or think im going there, lol.

And thanks "thehoe92" your knowledge is helping me quite a bit

Edited July 23, 2009 by JZeFF

[mr.p]

sensitivity means alot, but when a sub is able to handle 3x the power it more than makes up for a lack of efficiency. also that is only one number in the equation as stated motor force and xmax also play very big roles in which subwoofer is better. and better is relative.

[Rogers]

great info guys... im learning stuff too...

[thehoe92]

digital designs FTW!

hit up there website they got tons of information on how to build boxes and lots of speaker terms and definitions explained.

[Boon]

The DC is not as sensitive because it has stiff suspension.

While this makes it slightly less efficient it means it has the ability to control the excursion of the cone better at higher power.

If you put 1000wrms to the Infinity it won't be louder, despite the higher sensitivity, because the coil will have jumped the gap or smashed itself to pieces on the bottom of the motor.

To achieve high sensitivity AND power handling requires an enormously powerful motor combined with stiff suspension and a design that allows for quite high excursion. Look at the Atomic APXX - HUGE motor, so still you could probably stand on the cone, but still has huge sensitivity considering it'll take 20kw.

I know it seems a bit silly that you would put a bigger motor on a sub then fight it with stiff suspension but remember that it's not about excursion, it's about transferring energy to the air

[CarAudioFab]

Just know DC is gonna be a better bet than Infinity haha