Lowest RMS rating a Death Penalty can handle

[VWBobby 10+ year member]

The sensitivity spec is worthless on a sub since it is derived at 1kHz.

Touché!

edit: Actually.....! Even if the spec is derived at 1Khz, it could be argued that a sub with better sensitivity would respond better than one with less sensitivity for the given watt.

It has been proven that a sub with a heavy coil will put out less db's than a sub that has a lighter coil, fed the same power.

Mass x Acceleration. If it takes less Force (power) to make the sub respond, chances are it will be louder and have less distortion below its peak than a sub with a heavier coil or suspension. //content.invisioncic.com/y282845/emoticons/nerd.gif.c6fa51ddf7ff75f1c0371fbc648f70ae.gif

Thoughts?

 

[helotaxi 5,000+ posts]

Doesn't work that way unfortunately. I can't remember the formula for speaker sensitivity but I do know that the only spec that really is going to give you an idea about the real efficiency of a sub is the ratio of moving mass to Bl. It is possible to have differing ratios and still have the same sensitivity rating.

 

[VWBobby 10+ year member]

That makes sense. Thanks for your input. It would be cool if people would do more A/B tests with various subs and post their results. I'm getting to the point where I can read specs and see about what it'll sound like, but real world testing is the best answer.

 

[michaellane 5,000+ posts]

come on man...why dont ppl care to learn anymore before buying all this crap? 200+ for a 850watt clarion lol learn a little and then buy urself a nice setup

 

[Kyle_Keating 10+ year member]

small signal sensitivity - the one you see in the spec's is simply the cone area, BL, Resistance and Moving mass. The entire formula is derived from those 4 numbers and here is how they work:

double the moving mass - lose 6dB

double the BL - gain 6dB

double the cone - gain 6dB

double the Re - lose 3dB

so simply put, if you add another woofer identical to the one you own what do you have?

twice the BL +6, twice the cone+6, twice the Re -3, twice the moving mass -6.

net gain = +3dB in raw sensitivity.

Large signal sensitivity largely depends on many other things but some of them include the xmax limitations and compliance limitations. If you run out of BL or compliance (suspension) linearity, this will reduce your sensitivity. Other variables apply that largely relate to frequency, system design and some of AC concepts, but that's the gist of it from a simple standpoint.

 

[sundownz Pro Seller]

but I do know that the only spec that really is going to give you an idea about the real efficiency of a sub is the ratio of moving mass to Bl.

Indeed //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

Motor force factor / MMS

Pretty good initial indicator for SPL in our testing.

As Kyle pointed out non-linear specs will have a big impact as well -- so this only works WELL assuming the drivers are otherwise similar.

 

[axeten 10+ year member]

Havent read the whole thread yet but here's a link to the science of underpowering speakers from JBL:

http://www.jblpro.com/catalog/support/getfile.aspx?docid=246&doctype=3

It will happen if the volume is right up on the sub. Regardless of whether your amp gain is at 50% or 90%. If you crank the volume or gain to make the music very loud.... it will F!$K the sub. I've seen it happen a few times

 

[50 black guys 10+ year member]

I guess my car audio shop has been telling me "fibs"

I find it hard to get any truth from a car audio shop salesman, lmao

 

[helotaxi 5,000+ posts]

Havent read the whole thread yet but here's a link to the science of underpowering speakers from JBL:
http://www.jblpro.com/catalog/support/getfile.aspx?docid=246&doctype=3

It will happen if the volume is right up on the sub. Regardless of whether your amp gain is at 50% or 90%. If you crank the volume or gain to make the music very loud.... it will F!$K the sub. I've seen it happen a few times

That tech sheet has nothing to do with subs.

 

[axeten 10+ year member]

That tech sheet has nothing to do with subs.

Same concept. If you crank up a sub that is underpowered, it will start to distort (which the human ear cant hear when its only slight) and eventually fail.

I've seen it happen, had it happen and heard a hell a lot of it happening so i dont see why people think its some sort of myth

 

[ultimate157 5,000+ posts]

Same concept. If you crank up a sub that is underpowered, it will start to distort (which the human ear cant hear when its only slight) and eventually fail. I've seen it happen, had it happen and heard a hell a lot of it happening so i dont see why people think its some sort of myth

You are over driving the amplifier circuit, and clipping the signal. A clipped signal produces a higher average output power, and if that average output exceeds the sub's thermal power handling, it will burn up the voicecoil. The problem here is still over powering a sub.

 

[helotaxi 5,000+ posts]

Same concept. If you crank up a sub that is underpowered, it will start to distort (which the human ear cant hear when its only slight) and eventually fail. I've seen it happen, had it happen and heard a hell a lot of it happening so i dont see why people think its some sort of myth

Distortion has nothing to do with the failure of a sub. What the tech sheet is discussing is the relative sensitivity of mids and especially tweets to the massive amounts of high frequency signal "generated" by the clipping of the amplifier. Even slight clipping can quickly overcome the power handling of a mid or tweet especially when you consider that the distortion effectively overcomes any active filters in place.