300 watt vs 1100 watts, whats up?

[Rick Q]

Hi, Newbee here, I'm thinking about setting up a new PA system for my band but have had this question for YEARS. Back in the day I used to run a couple of 300 watt Crowns and they not only were the goto amp they were LOUD. today I was looking at a Crown UltraTech UT1010 Power Amplifier and they claim it 1100 watts! Are they rating these differently no days or are these really that much more powerful?

I had a Alesis 100 watt as a playback in my studio and a client laugh at me and said his amps were all 1000 watts, I told him I'd put my oldschool stuff up against his anyday!

Hey Craig, nice finding you, I haven't heard from you since the old Recording magazine!

[MikeRivers]

Because an amplifier is rated at 1100 watts (or 300 watts) doesn't mean you run it at that power continuously. The practical difference is that, at the same listening volume, the 1100 watt amplifier will give you more headroom for transients than the 300 watt one, assuming that the speaker won't blow up. But for a given speaker in a room, you won't really get the system significantly louder with the higher power of these two amplifiers.

 

They way they specify amplifier power (at least among honest manufacturers) is a little different today than in the DC-300 era, because they're designing amplifiers differently. One thing that the modern designs do is allow you to have a couple of 2500 watt amplifiers that you can plug into a single 20 amp electrical circuit, because they don't draw power continuously unless you're just playing a continuous sine wave through them (and most warn you not to do that at full power for very long).

 

[Rick Q]

I understand what you are saying but I remember they used to talk about RMS and peak, is this similar to what you are talking about?

[MikeRivers]

I understand what you are saying but I remember they used to talk about RMS and peak' date=' is this similar to what you are talking about?[/quote']

 

They still talk about RMS and peak power, but you need to look at the spec sheet to tell just how they're measuring it. Many manufacturers just give a number with no qualifications and that isn't very informative.

 

The spec sheet for the Crown CT-1000 (the UT-1010 is the same amplifier with a different label) states that the power measurements are of average power measured at 1 kHz and 0.5% THD. That's fairly specific, assuming that "average" means RMS. It also states that the 1100 watts is in the bridged mono mode and running into a 4 ohm load. What it doesn't tell you is whether the amplifier can sustain that power output continuously (like for hours and hours) or for just a few seconds, before it either blows up or (hopefully) an internal protection circuit kicks in and shuts it down.

 

If you look at the spec sheet for the original Crown DC-300

http://www.crownaudio.com/media/pdf/legacy/DC300-spec-sheet.pdf

you'll see that they actually show graphs of power output and clearly state the operating conditions (load, one or both channels operating, It also states the maximum power at clipping, which is useful to know. The specs for the newer amplifiers are less detailed, probably because they're afraid there'd be too many people like you asking questions like this.

 

 

 

[WRGKMC]

The RMS wattage rating is a power consumption rating based on clean undistorted sound. Many amps can produce a higher wattage with clips the waves. PA heads often rate their maximum wattage bridged in mono pushing a 2 ohm load. That 1100W Crown may be as low as 350W per side run at 8 ohms so you need to look at the specs carefully. Wattage consists of volts and amps across a load. It is often misunderstood as a loudness rating.

 

In cars you have a similar rating called Horsepower. You can have a huge engine with high horsepower designed for a truck. It doesn't have allot of speed, because its designed to connect to a transmission with allot of torque to carry heavy loads. On the other hand you can have a very small car with a low horsepower and be very fast off the mark, but it does carry allot of weight. If you tried to pull a trailer with it the engine would blow out in no time.

 

If you look at light bulbs can have two light bulbs with the same wattage rating. An Incandescent bulb convert less than 5% of the power into visible light. The rest gets converted to heat. The brightness of a Fluorescent bulb getting the same wattage can be many times higher.

Bulbs are rated by their luminous efficacy. You see that rating on the boxes when you buy them now. The luminous efficacy of a typical incandescent bulb is 16 lumens per watt, compared to the 60 for a fluorescent light so manufacturers post the savings on your electric by comparing the brightness of a bulb vs wattage.

 

With amplifiers, untrained people look at the wattage it can produce but that's only one of many specs you have to look at. You have to look at what's connected to that amplifier to have a complete story. Speakers like light bulbs have efficiency rating. Its based on its sensitivity and involves SPL (sound pressure level), per watt and distance. http://www.digikey.com/Web%20Export/Supplier%20Content/PUI_668/PDF/PUI_speaker_power_distance.pdf?redirected=1

 

What you hear is based on decibels, not watts. Speakers convert watts to decibels and you use this along with other factors that involve the quality of the sound being produced. Different speakers are used for different jobs and they require different power ratings to do those jobs well. so choosing the right amp speaker combination is very important. you cant just look at wattage and say its the same with all amps. Like the light bulbs you can have a speaker that is very loud with low wattage, and another that produces little sound with high wattage.

 

Again Its like Horsepower in engines. You can have a small engine with a high ratio transmission which might be a guitar amp. The speaker is very efficient so a lower wattage amp and high efficient speaker can be very loud. The speaker doesn't push allot of bass so its not like you're pulling a trailer. Most of the tones are midrange so you don't need heavy duty cones to handle the bass, and the higher frequencies produce fast transients so you want a lighter cone to produce faster transients. Guitarists even prefer the cone to mechanically distort to get their angry tones at low volume.

 

On the other side you have your truck engine which has low transmission gear ratios and plenty of reserved power (headroom) You find these in PA heads and PA systems where you have an amp driving allot of bass through many large woofers. They may also be separated into subs mids and highs. The woofers may be less efficient but they have heavy duty cones that don't fall apart pumping those subsonic lows. In the case of a PA head, you often have crossovers that separate the full frequency of the head into lows mids and highs. The heads are designed to support all that additional circuitry and long cable lengths and still produce a high fidelity reproduction.

 

You could take that mac truck engine and stick it in a small car but you're going to have an efficiency issue, the same way as if you stuck the small car engine in a big truck. The small engine cylinders just don't produce enough horsepower to drive the transmission without stalling and the weight and power of the large engine has nothing to do with speed in the small car. You may have plenty of torque for a 4 wheeler but that doesn't mean it has high RPM for speed.

 

Same deal goes for heads and speaker systems. Your particular speakers may be most efficient when driven by a particular head, and using a higher powered head may do nothing or even hinder the sound quality. Transistors do have power curves and are designed to produce the best sound quality and frequency response when running about 50~75% of their maximum. Run too high you get clipping and too low and much of the signal fails to be faithfully reproduced. http://www.learnabout-electronics.org/bipolar_junction_transistors_06.php

 

If you don't look at both the head and speakers as a working unit its like looking at a car without a transmission. It doesn't matter how powerful that engine is if its not turning the tires. A good transmission is needed to make the wheels spin just like speakers are needed to convert the amps wattage to sound. If the two aren't properly matched you're going to have efficiency problems and a well matched pair can sound much better then an unmatched system.

[JeffLearman]

As explained above, you have to be careful about comparing specs. (In particular, pay attention to how many ohms that wattage is rated for. In yesteryear, it was usually spec'd for 8, today it's usually 4, which makes the number up to twice as big for the same total power.) That said, YES, today's power amps have far more clean power than those of decades ago, and in much lighter packages.

 

However, keep in mind that it takes about 10 times as much power to be about twice as loud. Sad but true. (That's assuming 10dB is twice as loud. "Twice as loud" is subjective, though. Most people report it to be between 6dB and 10dB. If you're at the 6dB end, then it only takes 4 times as much power. That's how the math works out, believe it or not.)

 

Now, there will be folks who tell you those old tube power amps sounded better than today's transistor amps. Maybe they're right; I couldn't say. Also, things like slew rate matter, which isn't covered by wattage, as well as a number of other specs. The best specs can do is get you in the ballpark. For a given speaker efficiency rating, you can calculate the maximum SPL, and with experience of max SPL values you get a clue what you need for a given application.

 

For example, my keyboard stereo monitor rig is 375 watts per channel into 8 ohms, and my speakers are 99 dB SPL at 1W at 1 meter.

 

To calculate max SPL, start with 99 and add:

10 dB for 10 times the power (1W to 10W)

another 10 dB for 10 times the power (10W to 100W)

3 dB to double the power (100W to 200W)

another 3dB to double the power again (200W to 400W, close enough!)

 

So, that's two rules to remember (10 times the power adds 10dB, double the power adds 3dB), and yields 99 + 10 + 10 + 3 + 3 = 99 + 26 =105 per speaker. Double it (double the power) because it's stereo, that adds 3 more, for a total of 128dB SPL. Now, that's with my ear a meter from the speaker, and it's theoretical. They don't actually get quite that loud, but I know from experience that's enough for a pretty darn loud blues band, and if it gets too loud on stage for them, I quit the band. That is, good for stage levels around 110 dB SPL.

 

When I consider replacing it, I use 128dB SPL (theoretical max) as a rough guide for what to consider and what to rule out. No doubt there are setups that come out to 125 but sound better or louder, but anything under say 122 is very unlikely to be in the ballpark. And there's crappy stuff that works out to over 130 but won't loud and/or clean enough to suit. But there's no point paying for a quality system that's much over that level.

 

Folks who have experience with FOH and different sized venues will have an idea of how much SPL they'll need to handle a venue of a given size.

 

BTW, not only do today's amps have more clean power in inexpensive and light packages, today's speakers sound better and are more efficient. All in all, it's a lot easier and cheaper to be loud and clean today than it was when I was first gigging, in the 70's!

 

IMHO, the best bets today are powered speakers (even though I don't currently use them, except for one I use for rehearsal). With a powered speaker, the amp can be tailored to the speaker, the cabinets are bi-amped (which was always a good thing), and they're light and convenient. If I was to get a pair of powered speakers for general use today, I wouldn't hesitate to pick up a pair of EV ZLX-12P, which sound great, are loud, light, and inexpensive at under $400 each.

[JeffLearman]

BTW, you shouldn't need 1000 watts per channel in the studio, unless we're talking about powering a set of soffit monsters (and better bring your earplugs!) Studio speakers are less efficient than the stage speakers I've been discussing, trading off efficiency for accuracy. Even then, though, you don't need that much. However, there are some bi-amped speakers rated at 1000W because they have two 500W amps, one for woofer and one for tweeter, which means you'll never use 450 of the tweeter's available wattage. Evidently it's just cheaper to have two of the same amp than to optimize for the lower power requirement of the tweeter. (And those are live speakers. I shudder to think of 1000W studio monitors!)

 

But someone might have some 1000W amps he happens to be using in the studio. Nothing wrong with that, but you sure shouldn't need it! Whose ears are you trying to destroy?

[dboomer]

Because an amplifier is rated at 1100 watts (or 300 watts) doesn't mean you run it at that power continuously. The practical difference is that' date=' at the same listening volume, the 1100 watt amplifier will give you more headroom for transients than the 300 watt one [/quote'] Right. If you are running at 30 watts and want 15 dB of headroom then it will take an amp capable of 1000w to do it.

[WRGKMC]

My studio is a converted garage and I use it as a studio and a rehearsal room. Besides my studio monitors I can run a tap to my Stereo PA. I run Crown CE2000 and Peavey 500 so I can crank a total of around 1000 watts per side when I include my studio monitors. I don't do that very often but I do have that option for testing the mix to see how it sounds loud or when I had a band members over who wants to hear their mixes at live levels. I can get away with cranking it that loud because my studio is sound proofed and very dead sounding with practically no reflections. Its amazing how direct the sound is when you have a dead room. Its allot like having a sound system outside.

 

When I rehearse with a band I can use two amps cranked very loud and the perceived loudness is much lower because of the lack of reflection. If you have monitors in even a mildly reflective room the perceived loudness will appear to be much louder, so the room you use with the monitors will make a really big difference. If you have a room like a living room with allot of sound absorption items you may need more power then a smaller or reflective room just because of the longer ambient trails the reflections cause.

[Anderton]

I don't know as much about power amps as the others in this thread...I kind of stop at the output jack, if you know what I mean. However, I was testing out a variety of powered monitors with amp sim software to checkout viability as FRFR (full range, flat response) amps. With Cerwin-Vega being part of Gibson, I had access to their P1500X and asked the head of the company why it sounded louder than a competitor's product with a higher rating. That led to about a half-hour conversation with someone who lives this stuff, but here was my takeaway.

 

Most wattage specs are meaningless because they rarely state the testing protocol, the efficiency of the speakers, and the amount of distortion that’s considered acceptable (for example, an amp could be rated at 150 watts with 1% distortion but at 200W with 10% distortion). Without knowing this kind of information, you’ll never be able to compare apples to apples—it would be like measuring gas mileage for one car speeding down a highway, and another coasting downhill in neutral.

 

As to the issue with the P1500X vs. the competitor, they use different testing protocols. C-V’s power rating is based on the maximum clean power level before distortion (past that point, a limiter kicks in so it won’t play any louder anyway). Some companies allow the amp to distort before the limiters engage, while others give a power rating with no protection circuitry (limiter) engaged at all. The result is essentially a theoretical value—it’s like saying, “This is a 1000 watt amp” and then adding in fine print “but that much power would blow up the speakers, so the actual output is 250 watts.”

 

Output also depends on speaker efficiency, not just wattage. If the speakers aren’t efficient, the power just becomes heat and produces no sonic benefit anyway. It's the analogy WRGKMC drew to light bulbs.

 

Bottom line: Good luck comparing PA system specs. It seems the only foolproof option is to ignore the numbers, and put different systems through their paces in a performance situation—you’ll find out which ones deliver and which ones don’t.

[JeffLearman]

Most wattage specs are meaningless because they rarely state the testing protocol' date=' the efficiency of the speakers, and the amount of distortion that’s considered acceptable (for example, an amp could be rated at 150 watts with 1% distortion but at 200W with 10% distortion). Without knowing this kind of information, you’ll never be able to compare apples to apples—it would be like measuring gas mileage for one car speeding down a highway, and another coasting downhill in neutral.[/quote']Bingo. In addition, is the rating what the amp can pump out continuously, or just for brief moments to provide headroom? It's often not clearly spelled out.

 

All you can use the numbers for is a gross ballpark assessment. 10 times the rated power is likely to be significant. Twice might or might not be.

[dboomer]

However an amp's rated peak power is much more relevant to how it "sounds" as amplifiers never put out their continuous rated power when music is the source.

 

Specs do have meaning but unfortunately they are in engineer speak that consumers don't understand. Couple that with consumer's desire for a single number answer to a much more complex set of circumstances.

[JeffLearman]

However an amp's rated peak power is much more relevant to how it "sounds" as amplifiers never put out their continuous rated power when music is the source.

 

Specs do have meaning but unfortunately they are in engineer speak that consumers don't understand. Couple that with consumer's desire for a single number answer to a much more complex set of circumstances.

No kidding! That's why they spec watts rather than SPL for many powered speakers. In the eyes of too many consumers, watts is the "goodness number".

[blue2blue]

The RMS wattage rating is a power consumption rating based on clean undistorted sound. [...]

 

I'm thinking you didn't mean power consumption but rather output.

[WRGKMC]

 

 

I'm thinking you didn't mean power consumption but rather output.

 

I actually used the term properly but you just don't hear it used that way very often.

 

There is no wattage until a load is connected. Then the formula I x E=P works. You have no current until you have a load so you have no power being consumed. Wattage can be seen as a Potential value if it has a give load connected, but "watts" is a measurement of power consumption as well as potential power production source. I know this is splitting hairs but I did state it that way because I wanted to make the point you have to have a load to get wattage.

 

Wiki

 

Total system power is a term often used in audio electronics to rate the power of an audio system. Total system power refers to the total power consumption of the unit, rather than the power handling of the speakers or the power output of the amplifier.

 

 

[blue2blue]

 

 

I actually used the term properly but you just don't hear it used that way very often.

 

There is no wattage until a load is connected. Then the formula I x E=P works. You have no current until you have a load so you have no power being consumed. Wattage can be seen as a Potential value if it has a give load connected, but "watts" is a measurement of power consumption as well as potential power production source. I know this is splitting hairs but I did state it that way because I wanted to make the point you have to have a load to get wattage.

 

Wiki

 

Total system power is a term often used in audio electronics to rate the power of an audio system. Total system power refers to the total power consumption of the unit, rather than the power handling of the speakers or the power output of the amplifier.

 

Wikipedia http://en.wikipedia.org/wiki/Total_system_power:

[TABLE=class: wysiwyg_table_wysiwyg_table_metadata wysiwyg_table_wysiwyg_table_plainlinks wysiwyg_table_wysiwyg_table_ambox wysiwyg_table_wysiwyg_table_ambox-content wysiwyg_table_wysiwyg_table_ambox-Original_research]

[TR]

[TD=class: wysiwyg_table_wysiwyg_table_mbox-image][/TD]

[TD=class: wysiwyg_table_wysiwyg_table_mbox-text]This article possibly contains original research. Please improve it by verifying the claims made and adding inline citations. Statements consisting only of original research should be removed. (October 2008)[/TD]

[/TR]

[/TABLE]

Total system power is a term often used in audio electronics to rate the power of an audio system. Total system power refers to the total power consumption of the unit, rather than the power handling of the speakers or the power output of the amplifier. This can be viewed as a somewhat deceptive marketing ploy, as the total power consumption of the unit will of course be greater than any of its other power ratings, except for, perhaps, the peak power of the amplifier, which is essentially an exaggerated value anyway. Shelf stereos and surround sound receivers are often rated using total system power.

 

One way to use total system power to get a more accurate estimate of power is to consider the amplifier class which would give an educated guess of the power output by considering the efficiency of the class. For example, class AB amplifiers are around 25 or 50% efficiency while Class D amps are much higher; around 80% or more efficiency. A very exceptional efficiency for a specific Class D amp, the ROHM BD5421efs, operates at 90% efficiency. ^[1]

 

In some cases, an audio device may be measured by the total system power of all its loudspeakers by adding all their peak power ratings. Many home theater in a box systems are rated this way. Often low-end home theater systems' power ratings are taken at a high level of harmonic distortion as well; as high as 10%, which would be painfully noticeable. ^[2]

Agreed with the Wikipedia editors about the need to clean up that article, for sure. Someone edited without understanding the Wikipedia ground rules and the need to cite authoritative sources for all factual contentions.

 

Moving beyond that, I bolded the section that, to me, seems to sum up (pardon the expression) what is wrong with this 'rating' -- it's fine if what we are rating is, indeed, its total mains power consumption with the aim of understanding the environmental and economic impact of its use -- but it seems to me all but meaningless as any sort of 'rating' of audio performance.

 

I am, of course, familiar with attempting to ballpark the probable potential audio power output of an amp from its mains power consumption in consideration with its class of operation. That's a not unreasonable tactic for a straight amplifier, but, of course, once we throw in other functions like tuners, DACs, lighted or graphical displays, etc, we quickly end up with far too many squishy variables in our ballpark, seems to me.

 

I do, of course, understand the notion that without a specified load, audio power output ratings are indeterminable.

[dboomer]

Well if you want to get technical, power amps do not put out Watts. They put out voltage. Watts are developed across the load.

[MikeRivers]

I think that Wiki article was intended to address the concerns of those who want to know why the circuit breaker doesn't trip when they plug their two 3000 watt powered speakers into the same outlet - or those who wonder where in the bar they can possibly find a 50 amp circuit [6000 watts divided by 120 volts] to plug them in.

[WRGKMC]

Power is the rate at which energy is generated or consumed and hence is measured in units (e.g. watts) that represent 'energy per unit time'. Watt definition

Watt is the unit of power (symbol: W). The watt unit is named after James Watt, the inventor of the steam engine. One watt is defined as the energy consumption rate of one joule per second. 1W = 1J / 1s

 

One watt is also defined as the current flow of one ampere with voltage of one volt. 1W = 1V × 1A

 

Ohms law is all about using two factors to derive a third unmeasured parameter. You would have no amps without current flow and current flow doesn't occur without a complete circuit.

 

We often rate an amp by its "potential" for producing power, not the power it may produce under normal operating conditions

 

When something is producing watts, work of some kind if being performed and therefore consumed. It may be converting electrical power into heat or an electromagnet converting electrical energy into mechanical.

 

The efficiency rating, is different. It measures how efficiently the is being used. how well it converts one energy type into another. In the case of a speaker the efficiency is of course how well a speaker converts electrical power into mechanical power. The efficiency is a measure of how well the energy was converted to mechanical power by reading the number of DB's it produces at 1W/1M.

 

 

This reading is very similar to miles per gallon in a car but not completely. There are many ways of getting efficient gas mileage. Weight, Gear ratio, Tire size, even the wind sheer can change mileage. You don't have a power vs results comparison like you do with a speaker. Gas is not power, its stored energy that costs money. People want to keep an eye on their money so MPG is a well understood rating but it really doesn't tell you much when it comes to performance.

 

If you compared horsepower to miles per gallon, then your be closer to comparing apples to apples. Horsepower is closer to watts of an amp. Then you could compare transmission ratios to gas mileage like you would watts vs. SPL for speakers.

 

We have a tendency to separate speakers from the head that drives them. If we were all gear heads that built race cars we'd be comparing engines to the drive train in the same ways. Horsepower vs. Speed, Torque, Acceleration and Mileage.