Wattage Rating

[gsdvip]

Quick Question.

My speaker are rated at 150W each. If I purchase an Outlaw Mono 200W Amplifier, will it be too much for the speaker if I don't crank it?

My HK AVR 230 receiver only puts out 50W per channel, with all channels going. I want to get more out of my system.

[nadams]

It shouldn't be too much for the speakers, depending on what speakers they are. you'd damage speakers faster by trying to play them at high levels with underpowered gear than you will by playing them at high levels on overpowered gear.

What speakers are they?

[Whadyasay]

You'll be fine, really. The extra power in the amps will simply let it handle audio passages of varying intensity with more clarity and less distortion, especially in the bass. Depending on the sensitivity of your speakers, pumping even 90 continuous watts into your speakers would likely be louder than you'd ever want to listen to.

Lower wattage amps can cause distortion in the actual signal, which can damage speakers physically.

[venomclan]

I agree with the others. More clean power is better for most speakers. My B&W's are rated to handle 150 watts. I used to have an Outlaw M200 to each of them with no problem. I now have a 250 watt Krell, which is conservatly rated and is probably closer to 400 watts. The speakers are fine and never sounded so good. Go for it.
Venom

[lomic]

I posted on FatWallet a few weeks ago in some HTiB thread saying it's safer to drive a 100w speaker with 200w than 30w and I got flamed for spreading "misinformation". I'm locking myself in this forum and never going outside again.

[Willow]

I wonder why you got flamed? what you say is also what i have heard in past all the time.

[gsdvip]

The speakers are Polk Monitor 50's. Thanks for the feedback. I'll go for it when I can afford the amps.

[dorokusai]

Iomic - Go back and tell them to go F themselves. Burn that bridge quick as it's apparently useless for audio information.

Give me a link, I'd love to go crazy on that thread.

[cfrizz]

Can I watch Mark? Sounds like it might be fun.

[tonyv1]

dorokusai-san with samurai sword a-swinging!

[ohskigod]

I'd love to see it too, its one thing to disagree with correct information, its another thing to rag someone about it if their dead on right :confused:

[gsdvip]

Originally posted by Whadyasay
You'll be fine, really. The extra power in the amps will simply let it handle audio passages of varying intensity with more clarity and less distortion, especially in the bass. Depending on the sensitivity of your speakers, pumping even 90 continuous watts into your speakers would likely be louder than you'd ever want to listen to.

Lower wattage amps can cause distortion in the actual signal, which can damage speakers physically.

Does this mean that the 200W amplifier won't be noticably louder than the 50W per channel that my receiver puts out, but only have more dynamic range?

I'd go with it if I can get a noticable increase in volume as well. Currently, DVD's are not that loud.

I would like the Monitor 50's to perform to their best, which I believe can happen with more power.

[okiepolkie]

In a sense, you would be correct.

Loudness is measured in decibels, so if you play your speakers a level that procuces sound at 85 db, then it will play at that level no matter what wattage is behind it.

However, and this is a big however, an amplifier that is designed to deliver 50watts/channel will begin to distort much sooner(at the same loudness) than the 200watt/channel amp.

Essentially, you will be able to play your at "louder" levels without the distortion.

[gsdvip]

Originally posted by okiepolkie
In a sense, you would be correct.

Loudness is measured in decibels, so if you play your speakers a level that procuces sound at 85 db, then it will play at that level no matter what wattage is behind it.

However, and this is a big however, an amplifier that is designed to deliver 50watts/channel will begin to distort much sooner(at the same loudness) than the 200watt/channel amp.

Essentially, you will be able to play your at "louder" levels without the distortion.

Even now it doesn't distort. It's just that on a DVD, I have turned it to -5dB, much of the time it is not as loud as I'd expect.

Thanks for the feedback. I wouldn't need an amp because of distortion, but because of the headroom. Maybe I can find a way for the DVD player to output more volume.

[PolkThug]

Do you know the sensitivity rating of the speakers? For a speaker with a sensitivity of 90db, here is a handy little chart to see the relationship between watts and decibels.

[PolkThug]

An 85db speaker, requires more power.

[bknauss]

Originally posted by dorokusai
Iomic - Go back and tell them to go F themselves. Burn that bridge quick as it's apparently useless for audio information.

Give me a link, I'd love to go crazy on that thread.

It *IS* safer to drive 30 clean watts into a 100W rated speaker than drive it with 200 clean watts. What happens is people go ahead and drive the crap out of the amp, clip the signal so much that its a square wave, and destroy the speakers.

[Whadyasay]

Clean watts, yes. The 200w rating is usually there for the peaks, like explosions and such, that can be presented clearly. 200W continuous output power into ANY speaker would be very dangerous to your hearing, much less the speaker. At most comfortable listening levels, you r really not putting much more than 20-30 watts average continuous through your speakers. But for loud hits, or high level bass notes/drum hits, more power on tap is needed at an instant to keep them clean and clear. So at 30w into your speakers for normal listening (pretty loud, actually), a certain peak may need 80w...that's where a 50w amp will struggle and produce more distortion at that level than a 150w amp, and it's that distortion that could damage a 100w rated speaker, whereas with the 150w amp, that distortion wouldn't even be there.

Also, larger speakers with multiple drivers benefit from more power, as each driver is basically an electric motor, requiring electricity to move the speaker cone. More power is needed to move those multiple motors quickly and efficiently in order to faithfully reproduce the audio material. Look at it as horsepower in a car. the more horsepower on tap, the better the car will accelerate at various speeds, especially when you're already cruising along on the highway. A lower horsepower car can still travel at 70mph, but the car with more horsepower will be able to pick up speed and pass other cars more easily.

Most DVD's are recorded at a lower reference level than say CD's, radio, and even Television programming because there is a greater dynamic range on DVD movie soundtracks...ranging from whisper quiet to loud explosions...so a lower reference levels leaves more headroom for the loudest passages. This is normal. How do you have your DVD player hooked up? Digital or 5.1 analog? For example, a CD will normally be in the -27 to -22 volume range on my system, whereas a DVD is normally between -19 and -15 for the same perceived volume level. You should be able to hear the reference volume differences when you play a DVD on the player compared to a recent music CD. HK's internal amps are quite good, as far as receivers go, and they are rather conservatively rated. Your speakers may be a bit low in their sensitivity rating (84-87dB 1W @ 1M range)...which is no indication of bad quality, just the way they are designed. If that's the case, then they would need more amplifier power to play at the same levels as more sensitive speakers, like some Klipsch models. This is where an eternal separate amplifier really helps. Don't worry about having to crank the volume level reading up on the receiver if used as a preamp into the Outlaw monoblocks...they can take it, and so should your speakers.

[dorokusai]

Originally posted by bknauss
It *IS* safer to drive 30 clean watts into a 100W rated speaker than drive it with 200 clean watts. What happens is people go ahead and drive the crap out of the amp, clip the signal so much that its a square wave, and destroy the speakers.

No kidding, thanks for the information.

[McLoki]

Originally posted by bknauss
It *IS* safer to drive 30 clean watts into a 100W rated speaker than drive it with 200 clean watts.
Load of crap in my opinion. (Not that my opinion is more valid than yours, I just don't happen to agree with you.)

Unless you are running test tones, most music and movies have some level of dynamic range to them. If you are running your 30 clean watts into a speaker and drums hit, a car explodes, whatever - you have no power to reproduce the sound with. Playing the same volume - you would be much safer with a 200 watt amp.

As far as sound quality goes, in most cases, you would again be better off with the 200 channel amp. Not only would you not worry as much about distortion, but you would also have better control over your drivers.

I have a pair of SDA-1b's that, at the same volume, sounds like absolute crap when run from my Onkyo AVR but never fails to impress when run from my external amplifier. I am sure in both cases I am running less than 10 watts into the speakers. Given your conclusion - if we all listen well below reference (witch many of us do) there is no reason to ever get more than a 50 watt receiver.

I would much rather purchase used pair of LSi's or SDA's from someone who ran them with a large external amp than to know they were driven with a low to mid-line AVR the entire time they were in the previous owners hands.

All just in my opinion of course......

Michael

[HBombToo]

Originally posted by Whadyasay
Clean watts, yes.

I agree. Thanks for your time... Capiche?(chspl)

Twin

[Tour2ma]

Speaker ratings are continuous power ratings.

Speakers can handle transients as much as four times their "rating"... some even more.

I have never worried about using too powerful of an amp (unless kids or drunks were present).

The 30th W out of my old Carver M-1.5t (considered by many to be a "dirty" amp, i.e., high THD at it's rated ouput of 375 wpc), will be the match of the 30th W out of any "clean" 30 wpc amp... and still have 10 times the power to go... 20 times if you dip into it's headroom.

I'd like a piece of that fatwallet thread too... maybe you can cuss over there...

[jmierzur]

Here is a link to Elliott Sound Products (http://sound.westhost.com/site-map.htm) that has articles related to the topic at hand, and others of general interest.

Another Rane (http://www.rane.com/note128.html) article on the subject.

[McLoki]

I found a decent article as well. (http://www.smr-home-theatre.org/Power/) Basically on how much power do you really need for audio.

While I don't agree with everything in the article, it is an easy read and makes many valid points that I had not thought of. (and have not been mentioned so far in this thread)

Michael

[bknauss]

Originally posted by dorokusai
No kidding, thanks for the information.

Nowhere was it explained before in the thread that its safer to drive a speaker with less clean power than rated instead of more clean power than rated. A huge misconception around the internet is that if you aren't feeding a 100W speaker 100W, you're going to destroy it. Not true as long as its not clipped to all heck.

Just trying to help out the people who don't have a lot of technical knowledge...

[bknauss]

"Load of crap in my opinion. (Not that my opinion is more valid than yours, I just don't happen to agree with you.)

Unless you are running test tones, most music and movies have some level of dynamic range to them."

Sounds like you don't listen to most CDs recently released... good! :)

"If you are running your 30 clean watts into a speaker and drums hit, a car explodes, whatever - you have no power to reproduce the sound with. Playing the same volume - you would be much safer with a 200 watt amp."

Definitely true. When I was giving power examples, the important part is the clean signal. As long as the material going through the amp and loudspeaker is clean when you're playing under the RMS rating of the speaker, you're good to go... well, good to go in the respect of safety. As mentioned, you'll have no dynamics and the material will definitely sound flat.

"As far as sound quality goes, in most cases, you would again be better off with the 200 channel amp. Not only would you not worry as much about distortion, but you would also have better control over your drivers."

Agreed.

"I have a pair of SDA-1b's that, at the same volume, sounds like absolute crap when run from my Onkyo AVR but never fails to impress when run from my external amplifier. I am sure in both cases I am running less than 10 watts into the speakers. Given your conclusion - if we all listen well below reference (witch many of us do) there is no reason to ever get more than a 50 watt receiver. "

I never said you shouldn't get a high powered receiver. I personally have a lot of power running through my system. I love the dynamics. And I also know I probably have a ton of head room during most of my listening levels (like you noted with many members here). I am simply saying if you want to be ultimately safe with drivers, going below rated power with a clean signal is safer than going greater than rated power with a clean signal. Unfortunately, the only way to compare power levels is to have either the same music playing or play a test tone. I'm a dork, so I play test tones a lot. I feel safer not sending a ton of power to my speakers during test tones :)

"I would much rather purchase used pair of LSi's or SDA's from someone who ran them with a large external amp than to know they were driven with a low to mid-line AVR the entire time they were in the previous owners hands.



All just in my opinion of course......

Michael "

Was that person 16 years old? They seem to like overdriving speakers!

[McLoki]

Originally posted by bknauss
Was that person 16 years old?
Actually 38 - Not that it matters for this discussion.

They seem to like overdriving speakers!
Not at all. I do enjoy audio and sharing what I have learned with others. (to be fair, I also enjoy a good argument on occasion)

When I purchased my Cinepro amp I called polk customer service to ask if it would be a problem running a pair of speakers rated at 150 watts per channel on a 500 watt per channel amp. Their responce was that they get calls every day for blown speakers from people trying to run a speaker on a low to mid-grade reciever and pushing it to far. The customer service rep that I had talked to stated that he had only heard of two or three calls in the years he has worked for polk where a speaker was blown from running to large an amp on it.

You can infer what you want from that conversation, but many companies have thermal protection for their speakers to protect from over driving them. I do not know of any that have protection from clipping. (at the speaker level)

the following quote is from a review of my amplifier:
Below is a sample of about 5 seconds of the Dolby Digital Soundtrack of the hit movie INDEPENDENCE DAY. It shows that, even with moderate dialogue and background levels of 10-20 watts, peaks on the special effects can require reproduction of levels 18 dB louder. This translates into peak power requirements of over 700 watts! We know of no amplifier, other than the Cinepro 3k6 that can produce this type of short term energy into your speakers. Please note that most quality home theater speakers can reproduce short term peak power in excess of 1,000 watts, without damage.

I will grant that no one in their right minds would consider 10-20 watts "moderate dialog" but it does indicate that most mid-line and lower AVR's will not be able to play action movies without some level of clipping. Whether this level of clipping will cause damage to your speakers is open for debate, but your 30 watt reciever will clip trying to play most movies.

_____________________________

There you go, I have stated my case and my sources. Your turn.

What sources have you read (or who told you) that they recommend running speakers with a 30 watt reciever rather than a high quality amplifier. Not can do, but recommend saving your money on amplification and putting it to other uses in your audio/video system.

Michael

[Tour2ma]

Agree, McLoki.... Will say that speaker thermal protection (or fuses) are a safeguard against clipping.


Originally posted by bknauss
Nowhere was it explained before in the thread that its safer to drive a speaker with less clean power than rated instead of more clean power than rated. There's a reason it was not mentioned... It's that we don't agree... at least I don't.

You're throwing out the term "clean power" as a qualifying condition. In the real world it is not a quaifier, it's a result... Clipping is "unclean". And it's a simple fact that a 30 W amp is going to clip before a 100 W, which will clip before a 200 W, which will... etc.


Originally posted by bknauss
A huge misconception around the internet is that if you aren't feeding a 100W speaker 100W, you're going to destroy it. Not true as long as its not clipped to all heck. Again with the qualiifer... Not on the thread's point.... The question was will I hurt "150 W" speakers with a "200 W" amp.

"Safety" is in the ears (and sensibilities) of the owner.

[McLoki]

Originally posted by Tour2ma
Agree, McLoki.... Will say that speaker thermal protection (or fuses) are a safeguard against clipping.
I was unaware of that. I thought the thermal protection was to keep the voice coil from overheating. - I also thought the voice coil would overheat from to much sustained power going into the speaker.

Was I incorrect on both counts or just one? How does it protect from clipping? (Not arguing the fact, just trying to understand it...)

Michael

[Tour2ma]

You're correct about tweeter heating. Due to the limited surface area of their VC, they are very limited in their ability to dissipate heat.

The more power/ current applied, be it in a music signal or as a result of clipping, the more heat generated.

Polyswitches and fuses also heat up as they pass current. Thus the protection factor.

[McLoki]

Originally posted by Tour2ma
You're correct about tweeter heating. Due to the limited surface area of their VC, they are very limited in their ability to dissipate heat.

The more power/ current applied, be it in a music signal or as a result of clipping, the more heat generated.

I must just be off today. That is exactly how I thought they worked, but I cannot figure out how a peak sound that is clipped generates more heat than a peak sound that is not (assuming the same power). I thought it was just a function of to much continuous power (or to many peaks in a row) that overwhelms the voice coils ability to dissapate the heat.

To use the example from before - how would a 50 watt reciever trying to duplicate a 150 watt peak (and only providing 100 watts(clipping)) generate enough heat to trip the whatever when a 200 watt amp duplicating a 150 watt peak (and generating 150 watts (not clipping)) would not? :confused:

Michael

[Tour2ma]

The Rane link above discusses clipping's generation of HF harmonics. Look for the table around mid-page.
http://www.rane.com/note128.html

While the article dismisses the harmonics as a cause of tweeter failure due to their low power, it chooses in the table to examine the clipping of a 100 Hz tone at 100 W... not a real world example with respect to either the single tone or the power level.

It follows the table with a more realistic example of a composite a HF sine wave atop the LF, but it does not repeat the harmonics analysis for the HF signal. Rather it erroneously states, "Notice that only the low frequency burst portion of the waveform clips...". Sorry, but I don't notice that at all.... in fact it is the HF "rider" signal that intially exhausts the amp's voltage capability and clips before the 100 Hz carrier does in the subsequent extention of the example.

The actual HF frequency is not stated in the composite signal (It looks to be around 3 kHz, but no need to state it if you've already decided to ignore it), but if we assume one of 15 kHz (approaching, but not at the upper limit of music) at a 5 W power level (probably greater than real world, but bear with me) and redo the table to show the generation of ultrasonics, i.e., HF exceeding 20 kHz...

Harmonic - Amplitude - Level - Power - Freq (kHz)
.....1................1/1..........-0.........5.00........15
.....3................1/3..........-9.5......0.55........45
.....5................1/5..........-14.......0.20........75
.....7................1/7..........-17.......0.10.......105
.....9................1/9..........-19.......0.06.......135
....11..............1/11.........-21.......0.04.......165
....13..............1/13.........-22.......0.03.......195

Almost 1 W total of ultrasonics that the tweeter will try, and fail, to reproduce. I say fail because we know from the specs that 24k is about as high as tweeters go. And this failure means that little or none of the electrical energy supplied above this frequency is converted into acoustic energy.

No driver is 100% efficient in converting electrical energy into acoustic. The energy that does not go to acoustic purposes goes to heat generation. I want to say that 60% is about as good as it gets, but I may be off here. However, with the ultrasonics it approaches 0% efficiency. Bottom line is that the ultrasonics' signals go to no good purpose, but only add to the tweeters' heat dissipation load.

So if in the above example a 60% efficient tweeter with a 5 W rating is used, it can safely dissiapate 2 W of heat energy and is fine with the base 15 kHz signal. But add the 1 W of ultrasonic energy and heat begins to build up, and failure will occur if left in this situation long enough.

I stated above that a 5 W - 15 kHz signal might not be real world (the power distribution in music does decrease with increasing frequency), but a music signal is so complex no one wants to deal with its analysis in detail. But any frequency over 3500 Hz is going to add an appreciably powered harmonic thaty exceeds 24 kHz, so with multiple frequencies > 3500 kHz in music, during clipping all generate harmonics that are additive in their impact on tweeters.

I have to think a bit more on the ultrasonics' impact on protection devices, but initial thought is that their added electrical current is just that to a polyswitch or fuse, no different than the music signal's current. Issue is I'd assume that the protection is designed with the tweeter's acoustic efficiency in mind, not the 0% that accompanies the utrasonics.

No claimed expertise here, just a simplified case based on what I read many, many years ago applied to more contemporary theory that does not ring true with me. And there are even more of them out there...

[PolkThug]

Originally posted by McLoki
I but I cannot figure out how a peak sound that is clipped generates more heat than a peak sound that is not (assuming the same power).

I think a clipped waveform takes on a square shape which creates more stress on the tweeter to try to reproduce it.

[John K.]

Possibly the best analysis available online of the damage that may sometimes be done to a tweeter when an amplifier clips on high-level lower frequency signals is found on the St. Andrews site (http://www.st-andrews.ac.uk/~www_pa/Scots_Guide/audio/clipping/page1.html). Both the "harmonics" and "compression" hypotheses are analysed and other possible contributing causes are discussed briefly.

[Tour2ma]

Been through that paper before. Very even handed all the way through to his inconclusive Conclusion...
The main conclusion is that there is no obvious reason indicated by the analysis why we should either rule out any of the above factors entirely, or to assume that only one of them is always (or usually) a sole or primary cause. Which is in practice a more common cause, or whether they tend usually to act together, would be hard to say without more information on typical systems and musical waveforms in order to do a relevant statistical analysis, etc. Author must be a consultant...

[dorokusai]

Flip-flopper.

It is a good read, fairly straightforward, nothing groundbreaking.