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If I have 2 4-ohm subs that have an RMS of 600 each

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If your speakers (woofers) are slapping (bottoming out) you need to design a better enclosure, install a sharp low cut filter just below the port tuning frequency or invest in a speaker that will not bottom out (over designed magnet plates and/or braking coils at the extreme end of the voice coil)

I've seen woofers designed primarily for IB use that can handle oodles of power and have three or more inches of excursion. Placing such a driver on the floor cone down and giving a nice warble input over 100V makes it jump like a toad being chased by the family cat. Of course this is not good for the driver but makes the folks that see it laugh like hyenas. (until they realise how expensive that EXCURSION was! haha what a funny pun indeed.)

As for damaging speakers...

Well yes you can damage speakers from TOO MUCH power (duh) as well as too little since clipped waveforms will often oil can the drivers into oblivion. The dynamic offset literally roasts the voice coil bobbin and even if kapton/nomex or some other seemingly ablation proof space age material, the varnish will certainly burn rendering the whole mess unuseable once the gap fills with resin and the bitch locks up tighter than fort knocks. 😛

High powers are fun though if you have the program material to push the amps and your speakers can handle things without dynamic compression. Yeah it's always fun to watch clients in the control room jumping like war vets when the kick drum goes off and you have dozens of throaty JBL compression drivers pointed at you pumping out 135 dB EACH. Who needs pyrotechnics?
 
Originally posted by: sharkeeper
If your speakers (woofers) are slapping (bottoming out) you need to design a better enclosure, install a sharp low cut filter just below the port tuning frequency or invest in a speaker that will not bottom out (over designed magnet plates and/or braking coils at the extreme end of the voice coil)

I've seen woofers designed primarily for IB use that can handle oodles of power and have three or more inches of excursion. Placing such a driver on the floor cone down and giving a nice warble input over 100V makes it jump like a toad being chased by the family cat. Of course this is not good for the driver but makes the folks that see it laugh like hyenas. (until they realise how expensive that EXCURSION was! haha what a funny pun indeed.)

As for damaging speakers...

Well yes you can damage speakers from TOO MUCH power (duh) as well as too little since clipped waveforms will often oil can the drivers into oblivion. The dynamic offset literally roasts the voice coil bobbin and even if kapton/nomex or some other seemingly ablation proof space age material, the varnish will certainly burn rendering the whole mess unuseable once the gap fills with resin and the bitch locks up tighter than fort knocks. 😛

High powers are fun though if you have the program material to push the amps and your speakers can handle things without dynamic compression. Yeah it's always fun to watch clients in the control room jumping like war vets when the kick drum goes off and you have dozens of throaty JBL compression drivers pointed at you pumping out 135 dB EACH. Who needs pyrotechnics?
Click to expand...

Great post. Sounds like you work with in the pro arena. I'm more of a hi-fi guy, but its interesting that more and more pro-audio stuff is entering home theater...especially subs/amps.
 
Originally posted by: sharkeeper
If your speakers (woofers) are slapping (bottoming out) you need to design a better enclosure, install a sharp low cut filter just below the port tuning frequency or invest in a speaker that will not bottom out (over designed magnet plates and/or braking coils at the extreme end of the voice coil)

I've seen woofers designed primarily for IB use that can handle oodles of power and have three or more inches of excursion. Placing such a driver on the floor cone down and giving a nice warble input over 100V makes it jump like a toad being chased by the family cat. Of course this is not good for the driver but makes the folks that see it laugh like hyenas. (until they realise how expensive that EXCURSION was! haha what a funny pun indeed.)

As for damaging speakers...

Well yes you can damage speakers from TOO MUCH power (duh) as well as too little since clipped waveforms will often oil can the drivers into oblivion. The dynamic offset literally roasts the voice coil bobbin and even if kapton/nomex or some other seemingly ablation proof space age material, the varnish will certainly burn rendering the whole mess unuseable once the gap fills with resin and the bitch locks up tighter than fort knocks. 😛

High powers are fun though if you have the program material to push the amps and your speakers can handle things without dynamic compression. Yeah it's always fun to watch clients in the control room jumping like war vets when the kick drum goes off and you have dozens of throaty JBL compression drivers pointed at you pumping out 135 dB EACH. Who needs pyrotechnics?
Click to expand...

While your here could you answer a question?

I had a bandpass box with a boston accoustic pro woofer - pretty good woofer. Hooked up to an 800 watt (real RMS power, tested on a bench) amp. It hit so hard you would literally get sick to your stomach.

I blew two woofers. Meaning, totally blown. Ripped the whole cone/coil/spider right out of the woofer.

I never knew if that was just sheer over powering, or poor enclosure.
 
Why do you tards continue to say "underpowering" is bad? Just say what you really mean, which is sending any clipped signal to a speaker is bad. There's no such thing as "underpowering" a speaker, period. Oh noes, my volume isn't at 100%, I'm underpowering my speakers!!! :roll:

And of course you can overpower a speaker thermally, without it ever bottoming out.
 
Originally posted by: spidey07
Originally posted by: sharkeeper
If your speakers (woofers) are slapping (bottoming out) you need to design a better enclosure, install a sharp low cut filter just below the port tuning frequency or invest in a speaker that will not bottom out (over designed magnet plates and/or braking coils at the extreme end of the voice coil)

I've seen woofers designed primarily for IB use that can handle oodles of power and have three or more inches of excursion. Placing such a driver on the floor cone down and giving a nice warble input over 100V makes it jump like a toad being chased by the family cat. Of course this is not good for the driver but makes the folks that see it laugh like hyenas. (until they realise how expensive that EXCURSION was! haha what a funny pun indeed.)

As for damaging speakers...

Well yes you can damage speakers from TOO MUCH power (duh) as well as too little since clipped waveforms will often oil can the drivers into oblivion. The dynamic offset literally roasts the voice coil bobbin and even if kapton/nomex or some other seemingly ablation proof space age material, the varnish will certainly burn rendering the whole mess unuseable once the gap fills with resin and the bitch locks up tighter than fort knocks. 😛

High powers are fun though if you have the program material to push the amps and your speakers can handle things without dynamic compression. Yeah it's always fun to watch clients in the control room jumping like war vets when the kick drum goes off and you have dozens of throaty JBL compression drivers pointed at you pumping out 135 dB EACH. Who needs pyrotechnics?
Click to expand...

While your here could you answer a question?

I had a bandpass box with a boston accoustic pro woofer - pretty good woofer. Hooked up to an 800 watt (real RMS power, tested on a bench) amp. It hit so hard you would literally get sick to your stomach.

I blew two woofers. Meaning, totally blown. Ripped the whole cone/coil/spider right out of the woofer.

I never knew if that was just sheer over powering, or poor enclosure.
Click to expand...
I'm gonna go out on a limb and say that's probably a prefab box, isn't it?
 
Where was the break? Bandpass enclosures reduce excursion and increase pressure. The amp doesn't care it sends the same amount of energy although with a twist. One must remember there is a complicated relationship between the speaker motor, the excursion, its inductance, etc. Think what happens when a motor is stalled, it will draw high amps and the windings heat rapidly.

I saw things like this happen frequently with fifth and seventh order (most frequently the latter) as the builder strived for reduced excursion and max air column excursion. This makes the box hit very hard but will put tremendous stress on the voice coil bobbin attachment points. Very few consumer speakers are designed to handle this task at higher power levels...

Sooooo...

The BP box that seems to handle unlimited power (no bottoming ever) actually does have a limit and the limit unfortunately found when failure suddenly occurs in the form of catastrophic detachment of the voice coil assembly. I think I remember these units. I tested an isobaric (10" x2) system and it handled 400-500W OK but we did smell something strange with 550W RMS sine at 16Hz! The B&K was showing output with around 10%THD which is actually LOW for this class system. Anyways, the voice coil formers got hot enough (they were aluminum bobbins) that the cones started melting. Ouch. Impulses from the Synclavier digital drums were good and (before the thermal test) we had no real problems hitting the enclosure with very short hits of 2.8 kW or so.
 
Originally posted by: spidey07
Originally posted by: sharkeeper
If your speakers (woofers) are slapping (bottoming out) you need to design a better enclosure, install a sharp low cut filter just below the port tuning frequency or invest in a speaker that will not bottom out (over designed magnet plates and/or braking coils at the extreme end of the voice coil)

I've seen woofers designed primarily for IB use that can handle oodles of power and have three or more inches of excursion. Placing such a driver on the floor cone down and giving a nice warble input over 100V makes it jump like a toad being chased by the family cat. Of course this is not good for the driver but makes the folks that see it laugh like hyenas. (until they realise how expensive that EXCURSION was! haha what a funny pun indeed.)

As for damaging speakers...

Well yes you can damage speakers from TOO MUCH power (duh) as well as too little since clipped waveforms will often oil can the drivers into oblivion. The dynamic offset literally roasts the voice coil bobbin and even if kapton/nomex or some other seemingly ablation proof space age material, the varnish will certainly burn rendering the whole mess unuseable once the gap fills with resin and the bitch locks up tighter than fort knocks. 😛

High powers are fun though if you have the program material to push the amps and your speakers can handle things without dynamic compression. Yeah it's always fun to watch clients in the control room jumping like war vets when the kick drum goes off and you have dozens of throaty JBL compression drivers pointed at you pumping out 135 dB EACH. Who needs pyrotechnics?
Click to expand...

Great post. Sounds like you work with in the pro arena. I'm more of a hi-fi guy, but its interesting that more and more pro-audio stuff is entering home theater...especially subs/amps.
Click to expand...
Certain pro audio equipment do the job better than many hi-fi equipment. Drivers in particular.
 
Originally posted by: sharkeeper
Where was the break? Bandpass enclosures reduce excursion and increase pressure. The amp doesn't care it sends the same amount of energy although with a twist. One must remember there is a complicated relationship between the speaker motor, the excursion, its inductance, etc. Think what happens when a motor is stalled, it will draw high amps and the windings heat rapidly.

I saw things like this happen frequently with fifth and seventh order (most frequently the latter) as the builder strived for reduced excursion and max air column excursion. This makes the box hit very hard but will put tremendous stress on the voice coil bobbin attachment points. Very few consumer speakers are designed to handle this task at higher power levels...

Sooooo...

The BP box that seems to handle unlimited power (no bottoming ever) actually does have a limit and the limit unfortunately found when failure suddenly occurs in the form of catastrophic detachment of the voice coil assembly. I think I remember these units. I tested an isobaric (10" x2) system and it handled 400-500W OK but we did smell something strange with 550W RMS sine at 16Hz! The B&K was showing output with around 10%THD which is actually LOW for this class system. Anyways, the voice coil formers got hot enough (they were aluminum bobbins) that the cones started melting. Ouch. Impulses from the Synclavier digital drums were good and (before the thermal test) we had no real problems hitting the enclosure with very short hits of 2.8 kW or so.
Click to expand...

well I can't remember the exact specifics (5th vs 7th order bandpass) as it was 14 years ago.

The box was made by me according to recommended specs for this kind of a design (bandpass were very popular then)

As far as the failure I couldn't really tell. The voice coil was out of the cylinder, spider completely torn to shreds and surround totally torn. Voice coil seemed intact.

I didn't measure the output or scan it with a scope. But it was literally loud enough to make you want to throw up, a few people actually did....couldn't breathe.

Good discussion nonetheless.
 
Originally posted by: spidey07
Originally posted by: sharkeeper
Where was the break? Bandpass enclosures reduce excursion and increase pressure. The amp doesn't care it sends the same amount of energy although with a twist. One must remember there is a complicated relationship between the speaker motor, the excursion, its inductance, etc. Think what happens when a motor is stalled, it will draw high amps and the windings heat rapidly.

I saw things like this happen frequently with fifth and seventh order (most frequently the latter) as the builder strived for reduced excursion and max air column excursion. This makes the box hit very hard but will put tremendous stress on the voice coil bobbin attachment points. Very few consumer speakers are designed to handle this task at higher power levels...

Sooooo...

The BP box that seems to handle unlimited power (no bottoming ever) actually does have a limit and the limit unfortunately found when failure suddenly occurs in the form of catastrophic detachment of the voice coil assembly. I think I remember these units. I tested an isobaric (10" x2) system and it handled 400-500W OK but we did smell something strange with 550W RMS sine at 16Hz! The B&K was showing output with around 10%THD which is actually LOW for this class system. Anyways, the voice coil formers got hot enough (they were aluminum bobbins) that the cones started melting. Ouch. Impulses from the Synclavier digital drums were good and (before the thermal test) we had no real problems hitting the enclosure with very short hits of 2.8 kW or so.
Click to expand...

well I can't remember the exact specifics (5th vs 7th order bandpass) as it was 14 years ago.

The box was made by me according to recommended specs for this kind of a design (bandpass were very popular then)

As far as the failure I couldn't really tell. The voice coil was out of the cylinder, spider completely torn to shreds and surround totally torn. Voice coil seemed intact.

I didn't measure the output or scan it with a scope. But it was literally loud enough to make you want to throw up, a few people actually did....couldn't breathe.

Good discussion nonetheless.
Click to expand...

Sounds healthy.
 
As far as the failure I couldn't really tell. The voice coil was out of the cylinder, spider completely torn to shreds and surround totally torn. Voice coil seemed intact.
Click to expand...

Back to the future style? 😛

Yeah had a few of those in the LP days. Too fast of a stylus deployment with no infrasonic filter is really bad for woofers. Black widows can take this abuse but they really grundge at you and can really scare folks. (think of the diesel guys with their runaway nightmares!)

I didn't measure the output or scan it with a scope. But it was literally loud enough to make you want to throw up, a few people actually did....couldn't breathe.
Click to expand...

Diah-rear (crapping whatever you want to call it - fartless sh!tting) was the most common symptom but these folks were really hammered by some waves - 148 dB at 10 cps. Not a sound system but something used to test hulls of ships. Yeah, how low can you go? (before you have the uncontrollable urge to sh!t yourself that is! Haha contact free enema? yuckers!)

Good discussion nonetheless.
Click to expand...

Yeah it is and reminds me when we fux'd some really expensive cones and domes but those big Crowns were still kicking we dared each other to hold the output leads tightly and cranked up the AMPLITUDE on the signal synthesizer. Too bad it was on SQUARE WAVE. That sh!t hurt like no tomorrow. They should convert ole sparky chair of death to this and make it the chair of torture. NOTE: High power audio amps running unloaded can be damaged! If you can hear the music playing (through the amp) with no speakers you should back things down a little.

YIKE! Me spelling ain't so grand but consider sometimes I dun see what me types for FIVE SECONDDS due to latency GRRR
 
Well now that we are in the nitty gritty.....

I'm of the believe that you should have more power than you need.

You need X amount of power to get the SPL you are aiming for. Add a little bit of headroom (more power) to that and you should be golden.

I guess I'm lucky in that I really don't think I can overdrive my sepeakers (electrostats), talk about needing more power.
 
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