What is a speaker's power rating
08-16-2010, 07:46 AM
#1
What is a speaker's power rating
So there is a lot of beef on here, figured we could start a series of posts that focus on audio talk, so first off is something simple but sometimes miss understood.
So lets take this speaker for instance Dayton TIT280C-4 10" Titanic Mk III Subwoofer 4 Ohm | Parts-Express.com.
It could be any speakers, big or small, subwoofer or not but I had to chose one.
Question is, what does Power handling: 400 watts RMS mean exactly? What does it say to the power we should use, where did that number come from? Should we always give it no more then that... what about less or more?
So lets get those answers out.
So lets take this speaker for instance Dayton TIT280C-4 10" Titanic Mk III Subwoofer 4 Ohm | Parts-Express.com.
It could be any speakers, big or small, subwoofer or not but I had to chose one.
Question is, what does Power handling: 400 watts RMS mean exactly? What does it say to the power we should use, where did that number come from? Should we always give it no more then that... what about less or more?
So lets get those answers out.
08-16-2010, 09:13 AM
#2
its the peak handling of a speaker for it fails. lol
i have always been told to always cut that in 3/4 or half to get its actual peak performance with out overheating the coils. i could be incorrect tho but im sure we will both get schooled on this.
any takers.
i have always been told to always cut that in 3/4 or half to get its actual peak performance with out overheating the coils. i could be incorrect tho but im sure we will both get schooled on this.
any takers.
08-16-2010, 04:20 PM
#5
500 Watt CAFz'r
Join Date: Oct 2009
Posts: 730
RMS rating (root mean square) equations are based on a known power level/frequency (and not the frequency your SPL/SQ mind may initially wander to). As you all know, power is not constant. You change the volume, power changes. Even at a set volume, power isn't constant. The best a manufacturer could offer for an RMS rating would be an average of the lowest power and the highest power the voice coil can thermally handle, or multiple calculations at various power levels within that range. If you have ever taken calculus, you know how astronomical a task it is to standardize this process, let alone give 100% accurate measurements. Max power levels are typically the maximum average power a voice coil can handle without a thermal failure. There is inevitably room to move on any of these ratings, as they are averages to begin with. Testing will give you the direct answer to the question, but it is costly, and very time consuming.
08-16-2010, 10:02 PM
#7
Administrator
Join Date: Feb 2006
Posts: 16,855
^ lol.
In general, most manufacturers will rate a speaker on the thermal limits of the coil. Time is the big variable that is left out though. Enclosures introduce another variable. Crossover point introduces another variable. Program content is another variable (test tones vs. music)
Kicker used to rate their speakers for both short term and long term power levels. JL used to rate power handling depending on the enclosure their woofer was in. Rockford used to rate their woofers free air! Their rule of thumb was to double the power handling in a sealed box and double it again for a vented box.
It is too bad someone back when chose to rate the power handling of a speaker the same way we rate the power consumption of a lightbulb
In general, most manufacturers will rate a speaker on the thermal limits of the coil. Time is the big variable that is left out though. Enclosures introduce another variable. Crossover point introduces another variable. Program content is another variable (test tones vs. music)
Kicker used to rate their speakers for both short term and long term power levels. JL used to rate power handling depending on the enclosure their woofer was in. Rockford used to rate their woofers free air! Their rule of thumb was to double the power handling in a sealed box and double it again for a vented box.
It is too bad someone back when chose to rate the power handling of a speaker the same way we rate the power consumption of a lightbulb
08-16-2010, 10:34 PM
#8
hence the reason why folks that know what they are doing can run 2x, 3x, 4x the rms power to their speakers and never wet their pants, and those that don't seem to always have a foul odour emanating from their cars...it's not the urine...with only 1/2 rms!
09-07-2010, 12:05 PM
#9
So what does a speaker rating mean? Why can someone say they have 300watts or more sent to a comp set and won’t blow. Is it because they keep the gains down or is it more complex then that?
The ratings:
Manufacturers can choose different ways of rating a driver. Here are a few that I am aware of
-Free air, no xovers. This is basically like putting a speaker on the table and hooking up an amplifier to it, raising the volume and turning it back down a smidgen once the driver is going past its limits. Some raw drivers are measured this way such as tang band for instance.
-Boxed, no xovers: Many subwoofer marketers will actually recommend a power rating based on the enclosure parameters they recommend. This is very common and is usually a safe number to allow both satisfying results and low potential for the driver to blow.
-with a crossover: We would see this technique more with tweeters\dome midranges where the speaker can handle x amount of power as long as it has a specific minimum crossover point and slope.
How was your driver measured? Beats me, it could have been done differently to.
So how can we know how much a driver can take? How do I know when I can send 300watts or so to a comp set?
Well if one reads between the lines of the above 3 scenarios, we can perhaps see that power rating can depend on a few things and here they are:
-Enclosure volume\design
-frequency played
-crossover (this plays’ into frequency played).
So when it comes down to it, a speaker can handle more power at higher frequencies and less power at lows.
A crossover will attenuate the lows and allow the speaker to handle more power at the frequencies it is suppose to be playing.
A sealed, ported or free air box design will also impact how much power the speaker can take. The sealed box will usually allow more power handling since the box acts as “break” on the cone , ported will lower power handling because the speaker no longer has the sealed box “break” (putting it simply, ported boxes are more complex in how they handle power and how it affects excursion). Finally free air or infinite baffle usually is the least amount of power handling.
To get a good feeling on how much power a speaker can take, you need a box program such as bassbox pro, you can model your speaker in it and have a look at how much power it will take at what frequency and in what box type to make it reach full excursion.
I could post plots, if you cross a component set at 80hz then you can usually give the set a lot of power, more then the rating. If you don’t use a crossover, then it will play outside of it’s ideal range and it will be much easier to have it “bottom out” so to speak and go past it’s mechanical limitations….
So the answer to how much power a driver can take… well the answer is :It depends on the application.
The ratings:
Manufacturers can choose different ways of rating a driver. Here are a few that I am aware of
-Free air, no xovers. This is basically like putting a speaker on the table and hooking up an amplifier to it, raising the volume and turning it back down a smidgen once the driver is going past its limits. Some raw drivers are measured this way such as tang band for instance.
-Boxed, no xovers: Many subwoofer marketers will actually recommend a power rating based on the enclosure parameters they recommend. This is very common and is usually a safe number to allow both satisfying results and low potential for the driver to blow.
-with a crossover: We would see this technique more with tweeters\dome midranges where the speaker can handle x amount of power as long as it has a specific minimum crossover point and slope.
How was your driver measured? Beats me, it could have been done differently to.
So how can we know how much a driver can take? How do I know when I can send 300watts or so to a comp set?
Well if one reads between the lines of the above 3 scenarios, we can perhaps see that power rating can depend on a few things and here they are:
-Enclosure volume\design
-frequency played
-crossover (this plays’ into frequency played).
So when it comes down to it, a speaker can handle more power at higher frequencies and less power at lows.
A crossover will attenuate the lows and allow the speaker to handle more power at the frequencies it is suppose to be playing.
A sealed, ported or free air box design will also impact how much power the speaker can take. The sealed box will usually allow more power handling since the box acts as “break” on the cone , ported will lower power handling because the speaker no longer has the sealed box “break” (putting it simply, ported boxes are more complex in how they handle power and how it affects excursion). Finally free air or infinite baffle usually is the least amount of power handling.
To get a good feeling on how much power a speaker can take, you need a box program such as bassbox pro, you can model your speaker in it and have a look at how much power it will take at what frequency and in what box type to make it reach full excursion.
I could post plots, if you cross a component set at 80hz then you can usually give the set a lot of power, more then the rating. If you don’t use a crossover, then it will play outside of it’s ideal range and it will be much easier to have it “bottom out” so to speak and go past it’s mechanical limitations….
So the answer to how much power a driver can take… well the answer is :It depends on the application.
