Foxie
Wednesday 8th March 2006 - 9:39am
Peak and RMS Wattage Values
Amplifiers, headunits and speakers come with two power ratings, generally.
A max/peak/PMPO power rating, and an RMS power rating.
The first rating is a ridiculous abstraction. A subwoofer rated at 1000w peak will not be able to take anywhere near 1000 true watts before it dies.
These power ratings are used to woo the public into buying the product, and for no other reason.
If you ever see any of these ratings, discount them immediately, and look for the RMS value, which tells you the power the item will take/supply over a sustained period of time.
For example, Alpine Type-R subwoofers are rated at 1000w peak, but only 300w RMS. If you were to put 1000 true watts through the sub, as the ratings appear to indicate, the voice coils would cook within seconds.
As a further example, Alpine V-Drive headunits quote a maximum power output of 60w x4 - in reality this is around 28w RMS x4. The larger figures are there because they are more impressive to the customer than the real-life reality figures.
Don't let yourself be misguided - always match RMS values to RMS values
Revis
Wednesday 8th March 2006 - 3:22pm
hahaha, you just reminded me of when i sold my Alpine V12 amp on ebay. It had an RMS output of 367W and a guy emailed me and said "I don't care what RMS it is, tell me what the maximum wattage is please so i know whether to bid on it or not." made me laugh
Hulk Hogan
Wednesday 15th March 2006 - 12:20am
RMS / peak figures are purely pub talk - they realistically mean nothing!
EG the Type R is rated at 300w rms - what if the woofer was mounted infinite baffle? will it still handle 300w rms? what if the bass box was tuned to 15hz - would it handle 300w rms at 15hz and still produce something?
Amplifier RMS is pure shite as well - too many manufactures out there play on naive folk. They know that you dont want to see the peak ratings to they glamour up the rms ratings instead. Eg they will give you a 14.4v rms figure, or a 1%THD figure instead.
At the end of the day its the old saying "the proof is in the pudding" I hate all these "well my mate runs JL or Alpine!" etc - its all about listening to the product and evaluating if it is suitable to the user.
I'll give you an example - we build pro audio cars for a living, a potential customer wanted a pure SQ home hifi sound - so instantly we shot for Dynaudio System 360s and genesis amps. The whole combination worked out to be around £6k installed. Obviously the customer was not going to hand over that sort of cash without demo-ing the system - which we did. Before people start - the system was installed properly, set up properly blah blah blah - End result - did the customer like it? nope he was adamant that his £40odd JBL set up sounded better! Does that mean Dyns are shite? Does that mean Genesis amps are shite? nope Its down to the listener at the end of the day!
So all u guys out there that purchase with out listening - start listening!! Dont just take someones word for it!
bass mekanik
Wednesday 15th March 2006 - 12:30am
QUOTE (Hulk Hogan)
RMS / peak figures are purely pub talk - they realistically mean nothing!
EG the Type R is rated at 300w rms - what if the woofer was mounted infinite baffle? will it still handle 300w rms? what if the bass box was tuned to 15hz - would it handle 300w rms at 15hz and still produce something?
Amplifier RMS is pure shite as well - too many manufactures out there play on naive folk. They know that you dont want to see the peak ratings to they glamour up the rms ratings instead. Eg they will give you a 14.4v rms figure, or a 1%THD figure instead.
At the end of the day its the old saying "the proof is in the pudding" I hate all these "well my mate runs JL or Alpine!" etc - its all about listening to the product and evaluating if it is suitable to the user.
I'll give you an example - we build pro audio cars for a living, a potential customer wanted a pure SQ home hifi sound - so instantly we shot for Dynaudio System 360s and genesis amps. The whole combination worked out to be around £6k installed. Obviously the customer was not going to hand over that sort of cash without demo-ing the system - which we did. Before people start - the system was installed properly, set up properly blah blah blah - End result - did the customer like it? nope he was adamant that his £40odd JBL set up sounded better! Does that mean Dyns are shite? Does that mean Genesis amps are shite? nope Its down to the listener at the end of the day!
So all u guys out there that purchase with out listening - start listening!! Dont just take someones word for it!
bloody good advice- couldnt have put it better myself.
cornflakes
Monday 20th March 2006 - 4:05pm
one of my mates thinks that rms stands for really massive sub
iestynW
Saturday 29th April 2006 - 5:40pm
Even RMS values dont mean that much. I've got a pair of 12" subs in my boot, both rated at 50WRMS, connected to a 222W amp. The sound quality and potential loudness is far higher than any "300WRMS" sub I've ever heard.
bass mekanik
Sunday 30th April 2006 - 12:20am
which subs are they?
Alex_6n2
Sunday 30th April 2006 - 10:01am
I dont think that amp kicks out 222W rms though, and you just might be misguided as to what you've heard in the past.
Although their enclosure is massive which may help

(The whole boot!)
iestynW
Sunday 30th April 2006 - 11:19am
QUOTE (Alex_6n2)
I dont think that amp kicks out 222W rms though, and you just might be misguided as to what you've heard in the past.
Although their enclosure is massive which may help :lol: (The whole boot!)
Nah its not 222W rms, thats the peak.
Well actually they're enclosed in a speaker cabinet, which is in the boot...
I can't actually remeber the model name cause it's been ages since I sealed the cabinet. But I know they're Goodmans something or other, re-coned to 50Wrms... They rock!!
Alex_6n2
Sunday 30th April 2006 - 11:21am
Aye I know they are in a cabinet... but its the size of your boot!
mk3_nath
Sunday 3rd June 2007 - 10:39am
ok just a quicky:
obviously it is best to get the RMS of the amp and the sub/speaker etc. as close as possible but if the RMS of the amp is higher than that of the speaker will it just destroy the speaker or will that be ok?