did you read the full link to the subwoofer on amazon. it has parameters on it just look in the extra pictures on the left. they have specs.
All speaker-coils get warm or hot when driven. Most Tweeters are sent to tweeter-heaven that way by clipping amps for example. but when you can actually smell them they are definitely getting too hot. the smell is from the varnish that isolates the wire constituting the coil. When plastic materials start to smell they are on the point of melting or even burning. so sooner or later you will get a partialy shorted coil .....so good bye speaker.
You want a stronger speaker, sat twice the rating. With as large a coil as possible.
Greetings M
You want a stronger speaker, sat twice the rating. With as large a coil as possible.
Greetings M
so 2.5" coil rated 400 to 750W RMS? and run it at half rated power?
that sounds like a scar IVX 12-D2-V2 12" subwoofer but those are discontinued with no model replacing them. out of stock. only the 15" and 10" models are in stock. i havent found one that matches them in performance for the price
that sounds like a scar IVX 12-D2-V2 12" subwoofer but those are discontinued with no model replacing them. out of stock. only the 15" and 10" models are in stock. i havent found one that matches them in performance for the price
Last edited:
First of all no speaker with a 2,5" coil will handle more than 80 to 100 watts of real power without overheating and burning out no matter what ratings the manufacturer states. It is no more no less than a physical impossibility. But music is not a continuous sine wave nor is it a constant power pouring into the speaker.
Music consists of impulses where the relationship between the peak power of the pulse or pulses and the average power depends on the type and compression of the music.
The power ratings given by manufacturers should always be deeply mistrusted unless one knows exactly under which conditions these measurements were made.
In general an average 12" bass and/or subwoofer with a 2,5" coil can safely handle about 70 to 100 watts in the right enclosure, and with 4" coil up to about 150 watts.
Any of these will be able to handle up to 3 or 4 times that power in single pulses and probably up 200 watts of program depending as stated above on type of material and compression ratios.
Another aspect is that car hifi and speakers are designed to work with a volume of a cubic metre or two and not one of 10 to 20 times that like most living rooms. I would never use a car hifi speaker except for a car. 400 watts inside a closed car are a sure way to end up deaf as one might as well be standing directly below the jet engine of a starting 747.
Yet again I have to say that manufacturers , well aware of this , exagerate the ratings of car speakers even more than usual secure in the knowledge that any but the most crazy and/or already at least partly deaf will never drive them to those levels as the sound pressure levels in a car become unbearable and painful beyond a certain point.
In a normal home a well constructed subwoofer with something like 200 watts will have your neighbours pointing anti-tank-guns at you!
Third point is that one gets what one pays for. It does not have to be thousands of bucks but a complete subwoofer with enclosure and amp will be around a minimum of 600 to 800 of those and , if self built, 400 to 500. But please not with car hifi.
Music consists of impulses where the relationship between the peak power of the pulse or pulses and the average power depends on the type and compression of the music.
The power ratings given by manufacturers should always be deeply mistrusted unless one knows exactly under which conditions these measurements were made.
In general an average 12" bass and/or subwoofer with a 2,5" coil can safely handle about 70 to 100 watts in the right enclosure, and with 4" coil up to about 150 watts.
Any of these will be able to handle up to 3 or 4 times that power in single pulses and probably up 200 watts of program depending as stated above on type of material and compression ratios.
Another aspect is that car hifi and speakers are designed to work with a volume of a cubic metre or two and not one of 10 to 20 times that like most living rooms. I would never use a car hifi speaker except for a car. 400 watts inside a closed car are a sure way to end up deaf as one might as well be standing directly below the jet engine of a starting 747.
Yet again I have to say that manufacturers , well aware of this , exagerate the ratings of car speakers even more than usual secure in the knowledge that any but the most crazy and/or already at least partly deaf will never drive them to those levels as the sound pressure levels in a car become unbearable and painful beyond a certain point.
In a normal home a well constructed subwoofer with something like 200 watts will have your neighbours pointing anti-tank-guns at you!
Third point is that one gets what one pays for. It does not have to be thousands of bucks but a complete subwoofer with enclosure and amp will be around a minimum of 600 to 800 of those and , if self built, 400 to 500. But please not with car hifi.
Last edited:
then how does a sundown 750W RMS rated subwoofer handle true 750 watts RMS sinewave tone with a 2-and-a-half-inch voice coil? for 5 minutes straight with no problems?
None of what you just said even makes any sense
sundown even proved it posting their own youtube video showing live of their 12" 750W RMS subwoofer playing at the full 750W RMS and even higher than rated power and still not having any problems
None of what you just said even makes any sense
sundown even proved it posting their own youtube video showing live of their 12" 750W RMS subwoofer playing at the full 750W RMS and even higher than rated power and still not having any problems
Last edited:
Yes, starting with post #1.
The power ratings of amps and speakers is really about their maximum excursions which is their ability to play a brief pulse without limitation or for some better amps possibly continuous power output.
Drivers have about the same efficiency as incandescent lamps or bread toasters. Whatever power is sent through the driver, lamp, or toaster, 90% or more comes out as heat and the remaining 5% or 10% as light or sound.
With 700 watts or more, can you picture your sub driver handling for say, 30 seconds, the same heat as your toaster? Or a few large incandescent bulbs? Can you hold a 15 watt bulb in your hand?
If you can't do the simple Ohm's Law wattage math for a driver with a voice coil resistance of 6 Ohms, you certainly should learn it. (Or keep your silence.)
But music has very spikey waves. Big peaks but the average power is a far smaller figure than any continuous sine wave with the same peaks. So a recording could demand a very big peak - like 200 watts if we were looking at sine waves - yet be throwing into the voice coil only an integrated average of 5 watts over 20 seconds. So for that period, the excursion (and power draw) of the driver maxes at 200, but the heating is like 5 watts.
BTW, the whole long discussion of cab tuning is unsound. You might say the efficiency of the speaker is much higher at certain resonance points. But since sound is only a little part of the driver consumption, it doesn't matter much one way or the other. With EQ however, the power sent to the driver can be a whole lot different according to the EQ curve.
B.
Last edited:
Really?
Let´s compare a couple Real World objects, which follow the same set of Physics rules, and let´s see which claims are ...or are not ... nonsense.🙄.
1) This is a resistor which dissipates 750W.
All day long, 24/7/365 , etc.
Size: 45 cm long, 20mm diameter.
Made of: Nichrome, melting point of about 1,400 °C.
When dissipating 750W it runs so hot that only way to contain it is to let it stand in free air or inside a quartz glass tube or a ceramic bed.
2) now this is a resistor which **CLAIMS** similar power handling:
Size: 50mm long, 63mm diameter (I´m talking the typical actual winding) , actual radiating area about same as the quartz tube shown above.
Made of: epoxy glued copper wire which crumbles above 200/250C, wound on a Kapton former.
Are we supposed to believe both are even remotely comparable?
If you believe so, I have a nice bridge on sale for you. 😎
Many guys with multiple shots in the chest survive way more than 5 minutes, a few die even 1 or 2 days later ... do you think surviving anything for 5 minutes means there are "no problems"?
WOW!!!!!!!!!!!!!!!!!! NOW I am convinced!!!! 😱 😎 🙄
Whatever the claims, 63 mm (2.5") voice coil can withstand up to maximum 300W power measured with AES signal. It is not 300Wrms, or 300W with constant sinusoidal signal - like 300W heating element attached to the electrical 115/230Vac grid (like "resistor 1").
My post was dealing with this quote (bolded words):
The word "program" is used by ALL loudspeaker manufacturers to indicate two-times the AES power rating. So, 2.5" coil safely can handle audio signal up to 300W AES (not in "single pulses"!), or 600W "program power" (RCF 12N251). That means you can safely use 300-600Wrms amps, providing there is no clipping.
4" coil can handle from 300W AES up to 1000W AES power (depending on construction and materials), or 600W up to 2000W "program power" (RCF LF12X401). That is, to be used with up to 2000Wrms amps.
Last edited:
Some of the power is being turned into mechanical energy. There is additional cooling from airflow over the coil new fresh air being pumped in. so theres no way ALL of that 750W RMS is going into just heat like in your resistor example.
if it was. then the subwoofer wouldn't move even a single millimeter.
plus the heat is being dissipated fast enough that it keeps itself cool along with the fresh air being pumped in and out of the motor assembly and across the coil
theres no way the subwoofer coil is dissipating anywhere near 750W RMS as pure heat. its not a fixed resistor either. its resistance changes as it moves.
even if 750W RMS is going into the coil. some is being dissipated as heat. not all. and some is going into mechanical energy causing it to move. and the cooling from the coil moving is also helping to cool it.
if you held down the subwoofer cone with a big cinder block or something of course it would burn up almost immediately. its got no air flow. and cant move at all. and it behaves more like a fixed resistor. almost all the power is going into heating the coil. and with no airflow it gets super super hot very quickly.
if it was. then the subwoofer wouldn't move even a single millimeter.
plus the heat is being dissipated fast enough that it keeps itself cool along with the fresh air being pumped in and out of the motor assembly and across the coil
theres no way the subwoofer coil is dissipating anywhere near 750W RMS as pure heat. its not a fixed resistor either. its resistance changes as it moves.
even if 750W RMS is going into the coil. some is being dissipated as heat. not all. and some is going into mechanical energy causing it to move. and the cooling from the coil moving is also helping to cool it.
if you held down the subwoofer cone with a big cinder block or something of course it would burn up almost immediately. its got no air flow. and cant move at all. and it behaves more like a fixed resistor. almost all the power is going into heating the coil. and with no airflow it gets super super hot very quickly.
Last edited:
to apply 750 watts sinewave to a 4 ohm speaker you need to apply a sinewave of 55 volts which divided by 4 ohms gives a current of 13,75 amps which multiplied by 55 volts gives 756,25 watts. Considering that most digital multimeters are only giving a correct reading around 50 to 60 Hz have you checked what real voltage you are feeding to that speaker?
There is a difference between running a speaker on a power of "X" for 5 minutes when the metal of the center pole and ring pole near the coil are nicely cool and the whole motor-assembly as well so the cooling by the air around the coils is still optimal and running a speaker for a prolonged time when all this metal around it has had time to heat up and reach their internal operating temperatures for one. on the other hand it is true that a considerable part of the power is converted into mechanical energy so only a part of it goes into heat.
BUT : the part going into heat rises dramatically when the amplifier feeding the speaker is driven into clipping. so before claiming you are driving a speaker with 750 watts you should check that the sinewave you are driving it with is free of clipping and that the voltage applied is 55 volts clean AC.
An amplifier able to output a clean AC-signal of 55 volts needs supply-rails of 55 x 1.414 =77,77 volts not counting losses in the power transistors, so to feed clean 750 watts sine wave to any speaker your ampliefier need supply-rails of at least 85 volts DC under load. Why don`t you check this , both when idle and under load driving your speaker??
I have been building and repairing professional speakers for musicians and stages for some 40 years so I believe I have a little bit of experience and knowledge of the differences between specifications and ratings on one side and the real world on the other. 🙂
Music and sinewaves are two different stories, and so are true power levels apllied to speakers depending on a lot of factors like frequency, resonance, clipping levels and even ambient temperature.
He who does not want to believe me is welcome to apply a clean sinewave of 20 volts to his 4 ohm speaker for 24 hours nonstop or a voltage of 28 volts to an 8 ohm speaker for the same time and see what happens . In both cases you would be applying exactly 100 real watts to said speakers. Sinewave, clean without clipping.
BUT : the part going into heat rises dramatically when the amplifier feeding the speaker is driven into clipping. so before claiming you are driving a speaker with 750 watts you should check that the sinewave you are driving it with is free of clipping and that the voltage applied is 55 volts clean AC.
An amplifier able to output a clean AC-signal of 55 volts needs supply-rails of 55 x 1.414 =77,77 volts not counting losses in the power transistors, so to feed clean 750 watts sine wave to any speaker your ampliefier need supply-rails of at least 85 volts DC under load. Why don`t you check this , both when idle and under load driving your speaker??
I have been building and repairing professional speakers for musicians and stages for some 40 years so I believe I have a little bit of experience and knowledge of the differences between specifications and ratings on one side and the real world on the other. 🙂
Music and sinewaves are two different stories, and so are true power levels apllied to speakers depending on a lot of factors like frequency, resonance, clipping levels and even ambient temperature.
He who does not want to believe me is welcome to apply a clean sinewave of 20 volts to his 4 ohm speaker for 24 hours nonstop or a voltage of 28 volts to an 8 ohm speaker for the same time and see what happens . In both cases you would be applying exactly 100 real watts to said speakers. Sinewave, clean without clipping.
There are a few considerations to be gleaned from this page....
The art of speaker design, explained by a master - CNET
enjoy 🙂
The art of speaker design, explained by a master - CNET
enjoy 🙂
They had an amplifier capable of giving out over 3000 watts RMS with clean power in their testing.
I know my speakers are not clipping because i checked and re-checked it many times hooking up a tweeter with it with the subwoofer plugged in and listening for the buzzing noise from the tweeter and i made sure its perfectly clean and no buzzing from the speaker or tweeter. theres no clipping at all. after playing a few different frequencies to confirm the subwoofer is getting clean power i removed the tweeter.
When i'm playing music the voltage has only peaked at about 27v for a split second and averages around 6v to 20v when playing bass heavy music full of strong basslines so on average playing music its not getting very much power
if I play a sinewave tone it's about 27v RMS and it doesnt change very much with frequency except above 40hz. my multimeter i have can accurately read AC down to like 10hz and up to 10khz and it reads true RMS AC voltage not average.
I know my speakers are not clipping because i checked and re-checked it many times hooking up a tweeter with it with the subwoofer plugged in and listening for the buzzing noise from the tweeter and i made sure its perfectly clean and no buzzing from the speaker or tweeter. theres no clipping at all. after playing a few different frequencies to confirm the subwoofer is getting clean power i removed the tweeter.
When i'm playing music the voltage has only peaked at about 27v for a split second and averages around 6v to 20v when playing bass heavy music full of strong basslines so on average playing music its not getting very much power
if I play a sinewave tone it's about 27v RMS and it doesnt change very much with frequency except above 40hz. my multimeter i have can accurately read AC down to like 10hz and up to 10khz and it reads true RMS AC voltage not average.
well then do the math. 27 volts rms into a 4 ohm speaker gives a current of 27:4=6,75 amps and 27 volts x 6,75 amps gives a power of 182,25 watts c, rms, not 750. That equals to about 25% of said 750 and is actually quite a lot provided the speaker is efficient. Sensitivity 93 dB upwards.
Some more info for you since you obviously are into a bit of DIY.
Anything one wants to know can be found on internet these days with a bit of patience.
Building good speakers is extremely rewarding but it is difficult as well if one is not a technician with experience and even then. But that is not to say that patience and perseverance coupled with research can get you where you want to go.
https://www.techwalla.com/articles/how-to-make-your-own-subwoofer.
Speaker Box Enclosure Designer / Calculator
Please read it and start searching for more................
ah , and this
All You Wanted To Know About Subwoofers
Some more info for you since you obviously are into a bit of DIY.
Anything one wants to know can be found on internet these days with a bit of patience.
Building good speakers is extremely rewarding but it is difficult as well if one is not a technician with experience and even then. But that is not to say that patience and perseverance coupled with research can get you where you want to go.
https://www.techwalla.com/articles/how-to-make-your-own-subwoofer.
Speaker Box Enclosure Designer / Calculator
Please read it and start searching for more................
ah , and this
All You Wanted To Know About Subwoofers
my subwoofers rated for 250W RMS single coil 4-ohms
i just ordered another it'll arrive tomorrow free one day shipping. now i'll have a complete matching subwoofer setup and i'll have both subwoofers in the box.
i just ordered another it'll arrive tomorrow free one day shipping. now i'll have a complete matching subwoofer setup and i'll have both subwoofers in the box.
The efficiency is directly related to the sensitivity of the speaker, but they are not the same.
It's amazing how these two terms have been generalized as synonyms, when they definitely are not.
In order to clarify the doubts of the OP, you can not compare a pure resistance with a voice coil, the variables in play are not the same.
In a pure resistance there are no power compression phenomena due to variations in L / C / R when the temperature increases, nor are there any mechanical variables as in a speaker.
Power Handling Vs. Efficiency
" 2 Efficiency
Consider that the average high efficiency loudspeaker is typically no more than about 5% efficient. This means that only 5% of the applied electrical energy is converted into sound, the rest is dissipated as heat from the voice coil. This 5% efficiency speaker will be rated at 99dB/W/m - this is much higher than normally achieved.
If we could get one, a 100% efficient (direct radiating) speaker would convert 1W of electrical energy into 1W of acoustical energy. This will give us 112dB SPL (at 1W, 1 metre, when radiating into half space). Since no such loudspeaker exists, we must use what is available. Typical hi-fi loudspeakers are typically around 90dB/W/m - only 0.62% efficiency! 99.38% of all applied power is wasted as heat. "
Troels says that "A burnt speaker is always a misused speaker"
I think it is an irrefutable truth
It's amazing how these two terms have been generalized as synonyms, when they definitely are not.
In order to clarify the doubts of the OP, you can not compare a pure resistance with a voice coil, the variables in play are not the same.
In a pure resistance there are no power compression phenomena due to variations in L / C / R when the temperature increases, nor are there any mechanical variables as in a speaker.
Power Handling Vs. Efficiency
" 2 Efficiency
Consider that the average high efficiency loudspeaker is typically no more than about 5% efficient. This means that only 5% of the applied electrical energy is converted into sound, the rest is dissipated as heat from the voice coil. This 5% efficiency speaker will be rated at 99dB/W/m - this is much higher than normally achieved.
If we could get one, a 100% efficient (direct radiating) speaker would convert 1W of electrical energy into 1W of acoustical energy. This will give us 112dB SPL (at 1W, 1 metre, when radiating into half space). Since no such loudspeaker exists, we must use what is available. Typical hi-fi loudspeakers are typically around 90dB/W/m - only 0.62% efficiency! 99.38% of all applied power is wasted as heat. "
Troels says that "A burnt speaker is always a misused speaker"
I think it is an irrefutable truth
I can say I have a subwoofer with a 2.5 inch voice coil that can handle a lot of power. It just has to be long enough.
I wonder if you are driving the coil outside of the gap and seeing a great increase of power required. The second the voice coil goes out of the magnetic gap, back emf goes away and that resonance looks more like the DC coil resistance.
I wonder if you are driving the coil outside of the gap and seeing a great increase of power required. The second the voice coil goes out of the magnetic gap, back emf goes away and that resonance looks more like the DC coil resistance.
- Status
- Not open for further replies.