what does RMS mean?

[three6playa]

i'm looking at this amp
http://www.123dj.com/amps/pyramid/pa1800x.html
i don't get the rms part, is that the least amount it puts out?
and what about bridgeable mono, does that mean through one speaker?
and with speakers when it says like 300 rms and 500W peak power do you need to have 300W to run those speakers?

 

[mulester7]

i'm looking at this amp
http://www.123dj.com/amps/pyramid/pa1800x.html
i don't get the rms part, is that the least amount it puts out?
and what about bridgeable mono, does that mean through one speaker?
and with speakers when it says like 300 rms and 500W peak power do you need to have 300W to run those speakers?

RMS (Root Mean Square)

Generally, the average continuous power output an amplifier is capable of producing; power output an amplifier can produce consistently over extended lengths of time. RMS power contrasts to peak power, which is used for brief moments in order to recreate sudden, high-energy sounds (transients). RMS power can be produced continuously for the length of time the amplifier is in operation. It is the most important of the two power ratings (RMS versus peak) when researching an amplifier.

RMS is technically the average value of a particular waveform. When we say an amplifier has power output of some RMS figure, then we mean that amplifier is able to produce on average a certain amount of power. If you looked at a sine wave you would see a series of hills and valleys. The peak of the hill would be peak power. RMS measures the average area under the outline of the hill and its corresponding valley. RMS is a way of averaging the total waveform.

Note that RMS Power is equal to RMS Voltage multiplied by RMS Current. The term RMS is often used in audio to refer to continuous power output; however, RMS is not technically a power term since it applies to waveforms. However, you will hear RMS referred to most often relating to power.


Bridge (Bridging)

Amplification term used to describe the process whereby two channels of amplification are combined to operate as a single mono channel. Bridging allows a stereo amplifier to operate as a mono amplifier or any multi-channel amplifier to act as an amplifier with fewer channels. Each of the combined channels benefits from having more power than an individual, unbridged channel. However, bridging is not a substitute for using a single, high-quality mono (one channel) amplifier if that is desired. Bridged amplifiers provide more power but are limited in their ability to effectively output power into low impedance loads. Most amplifiers when bridged can only be operated at an 8 ohm level or higher. It is preferable to purchase two true mono amps or purchase a single stereo amp with more power than bridging two lower power amplifiers.

.....and, it would be advisable to have "at least" enough watts of amplification to match the maximum ratings of the speakers the amplification will be powering.....

 

[tejax]

RMS is the root mean square: the root of the mean of squares. English/american people are not very imaginative when it comes to naming stuff In electronics this represents the average, in this case power, it puts out.

As for bridegeable mono (I had to take a look at the link), yes, in this case means you can double the power if you just use one channel. This is common in dedicated amplifiers: trade channels for power at a constant total Nchannels*channel_power.

As for the speakers, those figures say that they can be driven with a nominal constant 300W power but they can handle occasional bursts that can go up to 500W. The sounds waves don't carry constant power, you got lower power for high frequencies, and more power on lower ones. The average might be 300W and have higher peaks of 1000W and lower peaks of 10W, for instance.

 

[Votrax]

The RMS value of an AC waveform is the DC equivalent. So basically the RMS power output of an amplifier is calculated using the RMS voltage output. Peak power doesn't really mean anything as it's not rated as continuous and most of the time isn't even attainable.

 

[three6playa]

yall think thats a good amp to get that i posted? 250W rms at 8 ohms with 2 speakers sounds good to me, probably shake the house and piss off the neighbors. cuz im gonna find me some 15's.

 

[mulester7]

yall think thats a good amp to get that i posted? 250W rms at 8 ohms with 2 speakers sounds good to me, probably shake the house and piss off the neighbors. cuz im gonna find me some 15's.

.....haha, be careful, some neighbors take the law into their own hands and have shotguns....Three6, the proposed amp is going to get it's signals from which receiver?.....

 

[Nick250]

i'm looking at this amp
http://www.123dj.com/amps/pyramid/pa1800x.html
and with speakers when it says like 300 rms and 500W peak power do you need to have 300W to run those speakers?

Not unless you are planing on going deaf. It depends on the efficency of your speakers, but I can not think of any home speakers needing 500W peak power to drive them. IMO it's a way high number, like saying one needs a 400 horse power car to commute with.

 

[Votrax]

yall think thats a good amp to get that i posted? 250W rms at 8 ohms with 2 speakers sounds good to me, probably shake the house and piss off the neighbors. cuz im gonna find me some 15's.

That would definitely piss off the neighbors. I would suggest the Behringer EP1500 over the Pyramid.

 

[agabriel]

I always thought that rms was the standard dev of something?

I'm going to do this in 3rd dem

So if I had variable var(1,1,1:5) = 1:5

the avg would equal 3 but the std would be equal to 1.4142.

What am I missing?

Anthony

 

[ironlung]

Not unless you are planing on going deaf. It depends on the efficency of your speakers, but I can not think of any home speakers needing 500W peak power to drive them. IMO it's a way high number, like saying one needs a 400 horse power car to commute with.

Personally I like the way mule thinks about this. A 1000 watt amp is not even breaking a sweat driving almost any load at a reasonable SPL. "Just sipping off headroom" as he says.

I drive a 1996 Toyota Camry 4 cylinder as a commuter. I also have a 320 HP Camaro SS. While they both get the job done getting me to and from work.

The Camry has to down shift 1 or 2 gears to climb a small hill and maintain speed. I have to use 85 to 90 percent of full throttle to merge on the expressway in the Camry. The little 4 cyl is working it's butt off in day to day traffic.

It could be argued the Camaro is overkill. But I'm not driving it as close to its max around town. Hills and merging in traffic are effortless for the big V-8. I have to take it to a track day or autocross to get near 90 percent max safely.

Isn't it the same comparison to handling transients and distortion in home audio?

 

[tejax]

agabriel, the rms is as the name says: the root of the mean of the squares. At a discrete level (that doesn't apply to audio, note) that is sqrt( 1/n * sum i=1..n xi ^2). There... the root of the mean of the squares. The stddev is a kind of rmsad, as in the root of the means of the average deltas (this is invented by me, don't care): sqrt(1/n * sum i=1..n (xi - xavg) ^2 ). So that's a different thing.

 

[WmAx]

Isn't it the same comparison to handling transients and distortion in home audio?

Your analogy is far removed from any relation to amplifier performance. When you consider the power/torque of a car and the way it feels in things such as hill climbing and accleration, you are considering a process that is an equation of mass, force, and incline that will vary greatly between products in practical applications. An amplifier, on the other hand, behaves exactly the same in amplifing an input signal regardless if it's a 100 watt or 1000 watt amplifier. The difference occurs only if you exceed the linear range[maximum unclipped power] of the smaller amplifier[in which case it becomes non-linear almost immediately and will distort/clip].

-Chris

 

[WmAx]

RMS (Root Mean Square)

.....

If you are going to copy and paste the text from a website as you have done here, then you should be careful to cite the reference/link that the text was copied from.

-Chris

 

[BMXTRIX]

He is speaking about power 15" speakers - large woofers basically...

This may create an entirely different point of view for some people. I know the Velodyne HGS series uses 1200+ watt (rms) amplifiers in their 10" models.

I'm not entirely convinced, that will some really good 15" speakers, that the power will be enough to drive them at high volumes adequately. But, what do I know?

 

[markw]

HEre'sa fun website to playwith. ...for you too, muleskinner.

http://www.radiolocman.com/electrical-engineering/circuit-cache.html?di=18850

 

[WmAx]

He is speaking about power 15" speakers - large woofers basically...

This may create an entirely different point of view for some people. I know the Velodyne HGS series uses 1200+ watt (rms) amplifiers in their 10" models.

I'm not entirely convinced, that will some really good 15" speakers, that the power will be enough to drive them at high volumes adequately. But, what do I know?

The speakers will have recommended power input specifications listed.

So far as size vs. SPL, a larger diameter driver will have a higher sensitivity[it will generate higher SPL for a given input signal] as compared to the same driver design with less surface area.

-Chris

 

[three6playa]

hey vortrax or anybody u recommended the behringer1500 i read up on it and it sounds better than that pyramid, it says 260w @8ohms but is that the rms wattage? it doesn't say the rms for anything.

 

[WmAx]

hey vortrax or anybody u recommended the behringer1500 i read up on it and it sounds better than that pyramid, it says 260w @8ohms but is that the rms wattage? it doesn't say the rms for anything.

Behringer has the specific ratings listed in the user manuals which are downloadable from www.behringer.com .

-Chris

 

[Votrax]

hey vortrax or anybody u recommended the behringer1500 i read up on it and it sounds better than that pyramid, it says 260w @8ohms but is that the rms wattage? it doesn't say the rms for anything.

The power is RMS per channel. I actually recommended it because it was about the same price as the Pyramid, but much better quality.

 

[WmAx]

The power is RMS per channel. I actually recommended it because it was about the same price as the Pyramid, but much better quality.

It's been a few years since I have seen or used Pyramid equipment, but from what I remember, it was built very poorly, did not meet advertised specs, and usually produced high noisefloor levels. Have they changed?

-Chris