wow, imagine that...
so i had the pleasure of watching smoke bellow from the box of my 10" l7 today with the same jbl amp. it played for about 2 minutes on a bass type song, and ofcourse, its locked up now. freakin waaaa!! ive blown just about every sub thats supposed to be top dogs....any suggestions now? wish i had kept all the subs ive blown over the last few years, would make for an interesting gallery to hang on the wall.
so i had the pleasure of watching smoke bellow from the box of my 10" l7 today with the same jbl amp. it played for about 2 minutes on a bass type song, and ofcourse, its locked up now. freakin waaaa!! ive blown just about every sub thats supposed to be top dogs....any suggestions now? wish i had kept all the subs ive blown over the last few years, would make for an interesting gallery to hang on the wall.
RTFM? I'm looking at Kicker L7 specs at Solo-Baric L7 | KICKER
" Max Rec Amplifier Power (WATTS PEAK/RMS)* 2000/1000
" * Assumes typical music program with minimal amplifier clipping; varies with enclosure size.
A high-powered test tone at 40 Hz bears very little resemblance to "typical music program", so you were probably running them way beyond their spec.
Typical music has a fairly large peak-to-average ratio. I've seen numbers from 10 to 20 Db, depending on type of music, measurement techniques, and who is doing the estimating.
Say 2000 watt peaks and a 9 Db peak/average ratio, the average power is only 250 watts. Half that at 12 Db ratio.
From Kicker's numbers, I'd be very surprised if these speakers lasted long with a continuous 600 Watt sine wave at any frequency, and not totally amazed if a 100 watt sine wave could fry them, especially in cabinet that constricted airflow.
Are you clipping them that badly? A clean signal won't cook a sub nearly as quickly. Also, if you're using truely top notch subs, why do you need so much power on so many occasions?
I have been wanting to say this for some time to everyone who has bought a "high powered" speaker. I am an oldtimer who does not believe in the power rating of most speakers. Take a 60 watt incandescent light bulb, the kind with a filament in it, turn it on and wait a few minutes. Put your hand on the bulb and keep it there, you will probably cause severe burns to your hand. Now imagine the very tiny voice coils in almost all speakers, now imagine a speaker sold with claims of KiloWatts or even hundreds of watts of continuous power handling capacity. Does it really surprise anyone that thinks about the heat being dissipated in that voice coil that the speaker vaporizes under sine wave testing? I heat a 14 foot x 28 foot room with a 1000 watt baseboard heater, the heater is sufficient to keep the room toasty warm even at -30degree temperatures, imagine all of that heat in a tiny 3 or 4 inch voice coil and the coil suvives. I can't
And 40 hz will not sound nearly as loud as 60 hz or higher at the same power level (Fletcher-Munsen) at least 10 dbspl (5 times the power!) so you may not think its using a lot of power when it is. The other thing I wonder about subs in cars is: at those low freqs. the car becomes the enclosure so cant the size of the car dramatically effect the efficiency /displacement of the driver? (open a window and now its a vented enclosure?)
since i started this post i have learnt a lot about voice coils and how they are made. from what i can tell (and im new at this) the wattage ratings are complete and total fabrications out of thin air and are based on almost nothing. its frustrating and its annoying.
its all about the amount of work that a speaker does in an amount of time. a sine wave (as i learned the hard way, see first post) is the most amount of work in the least amount of time. i would think this is where a speakers power handeling should be derived from. from what i can tell it is not even close to where they start. i suspect that the speaker manufacturers rely on the fact that there are pauses and breaks in music and therefore they can put whatever number they like on the side of the speaker and when it fails they can justify it with explinations like " listen to different music" or "turn it down". "listen to more Zamfir master of the pan flute than you can run all the power of your amp to our well designed subwoofer"
i cant seem to find any info anywhere that can accuratly define the position where a speaker can take a maximum amount of energy/heat in the shortest amount of time and be able to disipate it without failing. am i crazy or does this point sound like a valid point to find when manufacturing or selling a speaker?
i suppose the truth of the matter is that loud speakers especially big professional ones can take a large bursts of energy for short periods of time. from what i have seen this is the area which causes confusion with the ratings of power handeling. "well it CAN handle a million billion watts but only for a fraction of a second" so therefore they love to market them as million billion watt power handeling.
the good news is that these speakers can easily be rebuilt, the surrounds and the cones are indestructable and they are so big they are easy to work with. just put in a new coil and bingo bango new speaker. you can even drop in a stronger better built coil built on aluminum instead of kapton.
its all about the amount of work that a speaker does in an amount of time. a sine wave (as i learned the hard way, see first post) is the most amount of work in the least amount of time. i would think this is where a speakers power handeling should be derived from. from what i can tell it is not even close to where they start. i suspect that the speaker manufacturers rely on the fact that there are pauses and breaks in music and therefore they can put whatever number they like on the side of the speaker and when it fails they can justify it with explinations like " listen to different music" or "turn it down". "listen to more Zamfir master of the pan flute than you can run all the power of your amp to our well designed subwoofer"
i cant seem to find any info anywhere that can accuratly define the position where a speaker can take a maximum amount of energy/heat in the shortest amount of time and be able to disipate it without failing. am i crazy or does this point sound like a valid point to find when manufacturing or selling a speaker?
i suppose the truth of the matter is that loud speakers especially big professional ones can take a large bursts of energy for short periods of time. from what i have seen this is the area which causes confusion with the ratings of power handeling. "well it CAN handle a million billion watts but only for a fraction of a second" so therefore they love to market them as million billion watt power handeling.
the good news is that these speakers can easily be rebuilt, the surrounds and the cones are indestructable and they are so big they are easy to work with. just put in a new coil and bingo bango new speaker. you can even drop in a stronger better built coil built on aluminum instead of kapton.
this conclusion sounds as though it it very possible for CAR AUDIO and the speakers used in vehicles.
Good audio products generally do not tell lies in their advertising.
ya i totally agree. the guy who made me my replacement coils laughed pretty hard when i told him the ratings from kicker as to the power handeling. he is a local commercial speaker manufacturer and showed me a speaker that is rated at 1000W and it had a 6.5 inch voice coil and it had a liquid cooled magnet that was over 100 lbs. i cant find any car audio speaker anywhere that has a coil that big, but i have no problem finding claims to thousands of watts handeling "ya man but its just for a second"
the new coil i got explained to my has far more strength and is resistant to a higher heat and has better heat transfer properties then the original and he said if it was his speaker it would come with a 200 watt sticker on the side. its a pretty far cry from the 750/1500 claims from kicker.
the new coil i got explained to my has far more strength and is resistant to a higher heat and has better heat transfer properties then the original and he said if it was his speaker it would come with a 200 watt sticker on the side. its a pretty far cry from the 750/1500 claims from kicker.
Car audio. haha.
They know that they are mostly advertising to people who will grab the "coolest" looking speaker, and throw it into any box that will take it, and that most of their customers do not care about sound quality, only about blowing there eardrums out and looking cool doing it.
They fabricate parameters, because they can, and not many people will ever actually look into them. Most of the time they give no TS parameters, because they know that nobody will use them for the most part.
They rely on cabin gain of the car heavily when designing their speakers. Without that cabin gain, their subs are not anything to talk about. (again, for the most part)
And also, the "peak" power handling is just that - Power handling at a "peak", meaning not continuous. If you want to feed it a sine at its peak power rating, you are going to blow the living sh*t out of it.
They know that they are mostly advertising to people who will grab the "coolest" looking speaker, and throw it into any box that will take it, and that most of their customers do not care about sound quality, only about blowing there eardrums out and looking cool doing it.
They fabricate parameters, because they can, and not many people will ever actually look into them. Most of the time they give no TS parameters, because they know that nobody will use them for the most part.
They rely on cabin gain of the car heavily when designing their speakers. Without that cabin gain, their subs are not anything to talk about. (again, for the most part)
And also, the "peak" power handling is just that - Power handling at a "peak", meaning not continuous. If you want to feed it a sine at its peak power rating, you are going to blow the living sh*t out of it.
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Voice coil heating can be easily monitored by measuring changes in resistance, which has a positive temperature coefficient.
I figured out this formula for copper some time ago:
t0 = initial cold ambient/coil temperature (celsius)
r0 = initial cold voice coil resistance
r = voice coil resistance measured in hot
t = calculated voice coil temperature (celsius)
t = t0+[r-r0]/[r0*.00393]
For example, a copper coil measuring 3 ohm at 25ºC whose resistance has increased to 4 ohm is now at 110ºC. Magnet wire enamel is usually rated at 150ºC to 180ºC. Glues may whitstand less temperature.
For other materials the .00393 temperature coefficient is different.
EDIT: Remember to subtract the resistance reading that the multimeter gives when just touching both probes from all measurements. Remember to clean probe connections at both ends to get the lowest residual resistance reading. Old multimeters with a function wheel may need turning the wheel for cleaning internal contacts too.
I figured out this formula for copper some time ago:
t0 = initial cold ambient/coil temperature (celsius)
r0 = initial cold voice coil resistance
r = voice coil resistance measured in hot
t = calculated voice coil temperature (celsius)
t = t0+[r-r0]/[r0*.00393]
For example, a copper coil measuring 3 ohm at 25ºC whose resistance has increased to 4 ohm is now at 110ºC. Magnet wire enamel is usually rated at 150ºC to 180ºC. Glues may whitstand less temperature.
For other materials the .00393 temperature coefficient is different.
EDIT: Remember to subtract the resistance reading that the multimeter gives when just touching both probes from all measurements. Remember to clean probe connections at both ends to get the lowest residual resistance reading. Old multimeters with a function wheel may need turning the wheel for cleaning internal contacts too.
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Elliot article
There's a good article on power ratings and efficiency n the ESP pages:
Power Handling Vs. Efficiency
There's a good article on power ratings and efficiency n the ESP pages:
Power Handling Vs. Efficiency
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