when you look at the specs what is the rms and peak

[rookanga 10+ year member]

for example this amo

http://www.maxxsonics.com/hifonics/amps_brutus.html

BXi 2008D

1 x 650 W @ 4 Ω

1 x 1300 W @ 2 Ω

1 x 2000 W @ 1 Ω

for the 1 ohm (1 Ω ) is that the peak or rms watts

Click to read more...

 

[revrider1 5,000+ posts]

RMS, but I think these are overrated a bit. Not to sure, I dont keep up with HiFonics anymore...

 

[skadude016 5,000+ posts]

RMS (Rotations per Milli Second)

ya those new hifonics are over rated by about 200-300 watts

 

[IDSkoT 5,000+ posts]

RMS, but I think these are overrated a bit. Not to sure, I dont keep up with HiFonics anymore...

Hifonics give a little bit lower than RMS rating, if not RMS. I actually think that model does RMS.

 

[PsychoTheRapist 5,000+ posts]

RMS (Rotations per Milli Second)
ya those new hifonics are over rated by about 200-300 watts

Umm. Root Means Square. //content.invisioncic.com/y282845/emoticons/fyi.gif.9f1f679348da7204ce960cfc74bca8e0.gif

 

[revrider1 5,000+ posts]

lol

 

[endofdays89 5,000+ posts]

RMS (Rotations per Milli Second)
ya those new hifonics are over rated by about 200-300 watts

oh lordy

 

[rookanga 10+ year member]

I'm not talking about Hifonics amp, all I am saying is if you look at any amps specs and if they say 1000 at 1ohm is that the rms or peak and what do you mean the amp is overrated, like it says it can do 1000 watts when it really only does 800 or 1200 watts?

 

[revrider1 5,000+ posts]

All depends on quality of the amp. It will say RMS and thats what that is. Peak is MAX power, pay no attention to that number.

 

[bass-aholic 10+ year member]

I'm not talking about Hifonics amp, all I am saying is if you look at any amps specs and if they say 1000 at 1ohm is that the rms or peak and what do you mean the amp is overrated, like it says it can do 1000 watts when it really only does 800 or 1200 watts?

yep, and peak doesnt mean anything. sales pitch at best

 

[eharri3 10+ year member]

And someone correct me if Im wrong but just because it s an RMS number doesn't mean the amp is putting that out 100% of the time under all conditions. May do RMS if you put a continuous flat test tone through the speaker but if you're playing dynamic music could be putting out anywhere from a small fraction of that to 100% of it at different times. So when someone says they're feeding their speakers 150 watts all day with no problems, well, not really.

 

[OoMesKoO 10+ year member]

Umm. Root Means Square. //content.invisioncic.com/y282845/emoticons/fyi.gif.9f1f679348da7204ce960cfc74bca8e0.gif

Damnit i wanted to do that so bad.

//content.invisioncic.com/y282845/emoticons/verymad.gif.3f39c5c2fd57527b671fad3efdfac756.gif

 

[Enellz 10+ year member]

We should really have a thread that's a 'guide to buying car audio'. We get more vistors here that just browse the forums, not as many actually sign up. That way it'll be good info for them. Somebody make a sticky that's a guide for each part of car audio, amps, subs, batteries, etc. Just a thought...

 

[thch 10+ year member]

And someone correct me if Im wrong but just because it s an RMS number doesn't mean the amp is putting that out 100% of the time under all conditions. May do RMS if you put a continuous flat test tone through the speaker but if you're playing dynamic music could be putting out anywhere from a small fraction of that to 100% of it at different times. So when someone says they're feeding their speakers 150 watts all day with no problems, well, not really.

indeed. the simple explaination is that:

* the amplifier is rated using a sine wave, which is a signal that smoothly pushes the cone out and pulls it in. as such, there are times when the amp is working harder, and times where its not working at all.

the "RMS" power value corresponds to the average amount of work the amplifier uses each time it pushes the cone in and out. the peak power corresponds to the most power the amp could use to move the cone in/out.

THD refers to how smoothly the amp can push the cone in and out, with low THD values corresponding to "very smooth", and values generally limited to around 25% being "horrible".

If you are not playing a sine wave, but rather music, the amplifier will typically not put out as much power, on average, because the music doesn't call for it.

the technical:

* the amp is rated using a sine wave because it is a smooth function. further, derivitives and integrals retain the same shape. It also forms a sparse basis for periodic function, allowing THD calculations to be done easily. The known shape has a known and simple 2x crest factor, or in other words, the peak power is twice the average power.

The "RMS" power is an unfortunante term, as everyone who aspires to be technical will call it the "Root Mean Squared applied to Power". literally applying this operation to power doesn't make too much sense. RMS is used more for currents or voltages, where a RMS voltage or current would be used in an average power calculation.

THD relates the power in the fundamental tone to the power in tones that are integer multiples of it (in frequency). for full clipping this gives a fundamental with amplitude 4/pi, and an average power of 2x the unclipped case. this gives (2-(4/pi)^2) / (4/pi)^2 = 0.23 or 23% as the THD of a fully clipped signal.

Some people will use much larger amplifiers then required in order to allow large peak to average ratios (crest factors). This allows for small gains on things like EQs and other signal processors without worry that it might require more peak power then the amp is capable of. Peak power is actually a very valuable and relevant spec, but has largely been ignored due to abuses by various marketing departments.