Subwoofer help?

[jibberish]

the excursion damage does sound more likely UNLESS the voice coil only melted. IF the voice coil only melted with no damage, then a motion restrictive condition OR flat out overpowering condition existed.

you wont know unless someone looks at the damaged unit to determine what happened.

when a voice coil hits the basket it sounds like firing a .22. i think you would hear that.  mr foxxen is running down a certain path without all the information. very informative btw, but we dont really know what happened do we?

regarding you cant understand a 4500 watt pulse. let me try explaining some more.
if the amp at w/e gain is asked for a peak of double the volume, it requires ten times the power. the preamp will ASK the power amp for a 4500watt peak if the volume goes double the signal putting out 450watts. now here is a quote from the owner's manual of that bass amp. please notice they say 4x the current. RxIxI=watts. if RII=450 and i ask for some transient burst that requires 4x the current, we now have Rx(4I)x(4I) or actually the energy to drive 16times the rated wattage. and here's me exaggerating to 10 times only heh.

High Current Capability: When a power amplifier
is pushing a speaker cone and it needs to reproduce a
high-power transient like a string slap, the amp must
be able to deliver a high current pulse to maintain
cone control. If the amplifier can't do this it simply
cuts the transient off, producing an unresponsive
less out front sound. Creating these high current
pulses requires extra power devices (four times the
current required to deliver its rated power), larger
supply capacitors, and intelligent protection logic.
GK is the only instrument amplifier manufacturer
that goes to the trouble and expense, and it is a big
reason why GK amplifiers sound louder and cleaner
than other brands at the same power rating.


in other words for a millisecond, or like i said, however beefy the power supply is(and this one IS beefy) you can get a heinous energy spike. maybe more like 6000watts from this beast

once again, mr foxxen is off and running, but jury is out until we understand what the real damage was to that speaker.

[jibberish]

speaking of motion restrictive, if you use too massive of a driver at too high of a frequency, all that power gets burned as heat since the cone cant really ever get moving when it has to already go the other way. physical resistive damping=power dissipated as heat.

[neighbor664]

I'm really curious to hear this rig, She still using that awesome lawsuit Ibanez?

[Mr. Foxen]

the excursion damage does sound more likely UNLESS the voice coil only melted. IF the voice coil only melted with no damage, then a motion restrictive condition OR flat out overpowering condition existed.

you wont know unless someone looks at the damaged unit to determine what happened.

when a voice coil hits the basket it sounds like firing a .22. i think you would hear that.  mr foxxen is running down a certain path without all the information. very informative btw, but we dont really know what happened do we?

regarding you cant understand a 4500 watt pulse. let me try explaining some more.
if the amp at w/e gain is asked for a peak of double the volume, it requires ten times the power. the preamp will ASK the power amp for a 4500watt peak if the volume goes double the signal putting out 450watts. now here is a quote from the owner's manual of that bass amp. please notice they say 4x the current. RxIxI=watts. if RII=450 and i ask for some transient burst that requires 4x the current, we now have Rx(4I)x(4I) or actually the energy to drive 16times the rated wattage. and here's me exaggerating to 10 times only heh.

High Current Capability: When a power amplifier
is pushing a speaker cone and it needs to reproduce a
high-power transient like a string slap, the amp must
be able to deliver a high current pulse to maintain
cone control. If the amplifier can't do this it simply
cuts the transient off, producing an unresponsive
less out front sound. Creating these high current
pulses requires extra power devices (four times the
current required to deliver its rated power), larger
supply capacitors, and intelligent protection logic.
GK is the only instrument amplifier manufacturer
that goes to the trouble and expense, and it is a big
reason why GK amplifiers sound louder and cleaner
than other brands at the same power rating.


in other words for a millisecond, or like i said, however beefy the power supply is(and this one IS beefy) you can get a heinous energy spike. maybe more like 6000watts from this beast

once again, mr foxxen is off and running, but jury is out until we understand what the real damage was to that speaker.

The power rating on a speaker is RMS, and the burst output an amp can do isn't, speakers tend to be able to deal with brief peaks thermally but the max excursion limit (xlim) is pretty absolute, exceed that and its dead, briefly peak the RMS power going through, and it will cool off again soon after. Voice coil melting from too much power hitting it is sudden silence. More common thermal failure mode in modern speakers is the voice coil distorts from expansion an jams in the gap (basically, glues have got better so they don't melt so easily). Xlim might be limitations in suspension movement and such rather than just hitting the magnet, that is where you get creased cones and stuff that also misaligned the voice coil, make it rub an self destruct.

Basically, I assume excursion related failure because the excursion limit is way below the thermal limit, is much less negotiable and uncompressed detuned bass guitar is much more likely to cause that sort of damage.


The stuff about high frequencies damaging woofers is also myth, the speaker can dissipate plenty of heat, most energy that goes to it is wasted as heat regardless of how much it moves, and there is much more energy in low frequencies. If you put a high frequency into it with enough power to upset it, sure, but it would be the power upsetting it not the frequency, plus with a woofer the impedance at high frequency will tend to be high which drops the power going through it.

Edit: Should be required reading: http://barefacedbass.com/technical-information.htm

http://barefacedbass.com/bgm-columns.htm

Dude is less of a dick than Bill Fitzmaurice, BFM is more the guy to check for PA specific stuff.

[jibberish]

btw, i appreciate all the time you guys spend in these threads. i learn a ton from each discussion.