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post #331 of 371 Old 07-21-2014, 02:44 PM
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Originally Posted by archiguy View Post
Forgive the elementary nature of this question, but it's relevant to the topic of amplifier power in relation to loudspeakers. I honestly don't know, because I don't think I've ever heard it personally (I've always had plenty of power to comfortably drive any speaker array I've had) but have heard it referred to frequently:

What is "clipping"? What does it sound like? Can it really damage a loudspeaker? How?
You can hear clipping very easily. Use a factory car stereo to save on your hearing. Turn it up while listening to the sound. The sound will start to become harsh and as you increase volume, eventually it will be totally distorted. That's clipping.

If you ever owned a battery powered boom box or similar, and ran down on batteries you can hear VERY obvious distortion due to clipping as the batteries don't have enough power any normal listening volume.

So that's the spectrum really. No clipping, high frequencies like cymbals should sound clean ( as clean as the source allows) to trying to play a boom box with spent batteries. In between is varying amounts of distortion, with the high frequencies seeming to "fall apart" first. I remember some crappy receivers friends had which reached psychologically damaging distortion well before we got up to drinking party levels. And I wondered why some people seem immune to that horrid noise.

"But this one goes up to 11"
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post #332 of 371 Old 07-21-2014, 03:00 PM
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Quote:
Originally Posted by archiguy View Post
Forgive the elementary nature of this question, but it's relevant to the topic of amplifier power in relation to loudspeakers. I honestly don't know, because I don't think I've ever heard it personally (I've always had plenty of power to comfortably drive any speaker array I've had) but have heard it referred to frequently:

What is "clipping"? What does it sound like? Can it really damage a loudspeaker? How?
In short clipping is a kind of distortion that happens when an amp rens out of "steam." Generally it is recognized that at lowish distortion, one's response will be "that's loud." at some point the harmonics added by the distortion become clearly audible as grunge.

There are likely youtube demos of avr or stereo amp distortion. But to hear it big time just check out some youtube demos of guitar distortion pedals. What those devices do is clip the signal. Try, say, "ocd demo" in yout. You will hear the guitar without the distortion box then with it.

Now a one percent distortion is considered clipping for a hifi amp, but musical instrument amps are often rated with ten percent distortion, and I have read that guitar players will identify ten percent distortion as a "clean" sound. But you will get the idea.

For big guitar player fun, and to hear amp distortion versus stomp box distortion, look for the funny and brilliant Greg Koch's review of the prs hxda for sweetwater. Koch plus hxda should get you there in YouTube.

Theoretically because clipping generates higher harmonics there is some chance that a heavily clipping amp into a nearly overwrought tweeter can kill the tweeter. People talk about square waves from clipping but that's horsecrap. Square waves have about forty percent distortion. I doubt you could bear to listen to a system producing forty percent distortion.

If the clipped signal itself could kill speakers there would be no rock concerts or rock records, because the guitars are heavily clipped all the time. An acdc concert would last about 90 seconds before all the pa and guitar speakers blew
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post #333 of 371 Old 07-21-2014, 03:30 PM
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Originally Posted by turnne1 View Post
is evaluating test tones part of your buying decision?

I guess I have spent minimal time comparing test tones among different equipment

regardless if they sounded better...worse..etc vs what the audio components sounded like

My preference for actual sound far and away outweighs what I think about the test tones

Warren
No one has recommended using test tones to evaluate speakers (although it might show deficiencies that one was not aware of). Do you think a system can be properly eq'd without tones. Try that with music or movies.

This all started as a reference that room acoustics affect sound more than electronics.
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post #334 of 371 Old 07-21-2014, 03:39 PM
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Originally Posted by MUDCAT45 View Post
No one has recommended using test tones to evaluate speakers (although it might show deficiencies that one was not aware of). Do you think a system can be properly eq'd without tones. Try that with music or movies.

This all started as a reference that room acoustics affect sound more than electronics.

no I didn't say a system could be eq'ed without tones...not sure where you got that indication


I just said I would not use differences in test tones to evaluate my buying decision...nor have I ever spent much time listening to them short of a set up since they have no bearing on my buying decision

I have listened to quite a bit music in source direct mode though....which I " guess" is supposed to by pass the EQ'ing

I dont in practice listen to matrix ed channels by the audio piece

Warren

Rm 1 Samsung 64F8500 Onkyo 5508 prepro Sherbourn 5/1500A amp Atlantic technology System 350 THX Ultra speakers
Rm 2 LG 47LE8500 Pioneer SC37 Celestion 305 speaker system
Rm 3 Samsung 51E8000 Yamaha A2010 Kef 2005.2 speaker system
Rm 4 Panasonic 50ST50 Onkyo 5009/906 Mirage Omni sat speaker system
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post #335 of 371 Old 07-21-2014, 04:04 PM
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Quote:
Originally Posted by archiguy View Post
Forgive the elementary nature of this question, but it's relevant to the topic of amplifier power in relation to loudspeakers. I honestly don't know, because I don't think I've ever heard it personally (I've always had plenty of power to comfortably drive any speaker array I've had) but have heard it referred to frequently:

What is "clipping"? What does it sound like? Can it really damage a loudspeaker? How?
Lets kleer the air...
Clipping happens when a circuit is overdriven...
The circuit may be an input type like from a source component output level too high or an amplifier output stage. When an output stage is overdriven the amplifier sends out square waves which are very destructive to a loudspeaker, as they cause the motor structure of the loudspeaker (voice coil, magnet and gap) to heat up, twist and turn often destroying itself. Many users think that high output power is what destroys a loudspeaker...
But just the reverse is true, when a lowered power amplifier is pushed beyond its design limits it is more likely to generate the destructive square wave distortion. The square wave distortion destroys the loudspeaker, also note that many users are confused about a loudspeaker load to an amplifier, thinking it is just resistive..
When its actual load is actually reactive rather than being resistive and certain loudspeakers put a very reactive load to the amplifier's output stage. We have measured amplifiers putting out 250W into an 8 Ohm resistor but when driving a 4 Ohm 60 degree reactive load and its real power output can decrease by up to 70% down to 75W...

IMHO..
It is pertinent to carefully match the loudspeaker's load & sensitivity to the amplifier's voltage/current output capability. Especially crucial if one has large room and demands a high volume level. Thats why it is always best to have as much output power in reserve that one can afford.. It is very sad that today many AVRs are incapable of driving some of the higher quality loudspeakers, as the marketing/advertising boys have hyped the AVR's power output specs beyond reality..
They may deliver adequate power @ lower listening levels but when pushed harder..
Stand back...


Just my $0.03...
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post #336 of 371 Old 07-21-2014, 05:02 PM
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Quote:
Originally Posted by JHAz View Post
Theoretically because clipping generates higher harmonics there is some chance that a heavily clipping amp into a nearly overwrought tweeter can kill the tweeter. People talk about square waves from clipping but that's horsecrap. Square waves have about forty percent distortion. I doubt you could bear to listen to a system producing forty percent distortion.

If the clipped signal itself could kill speakers there would be no rock concerts or rock records, because the guitars are heavily clipped all the time. An acdc concert would last about 90 seconds before all the pa and guitar speakers blew
There's another theory that it has nothing to do with harmonics. The fact that it's clipping results in a higher average signal level. This makes sense, because rather than being a nice sine wave looking thing, it looks like a plateau, which obviously influences the average signal level. Now you have tweeters "seeing" a lot more watts than they were designed to handle.

At the end of the day though, it's the same problem. If you keep trying to reach rock concert levels with small living room equipment, you are asking for trouble. Alcohol also seems to effect people's better judgement and there's a theory drinking parties kill speakers. I had first hand experience with that once

http://sound.westhost.com/tweeters.htm

"But this one goes up to 11"

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post #337 of 371 Old 07-21-2014, 05:51 PM
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Quote:
Originally Posted by MichaelJHuman View Post
There's another theory that it has nothing to do with harmonics. The fact that it's clipping results in a higher average signal level. This makes sense, because rather than being a nice sine wave looking thing, it looks like a plateau, which obviously influences the average signal level. Now you have tweeters "seeing" a lot more watts than they were designed to handle.

At the end of the day though, it's the same problem. If you keep trying to reach rock concert levels with small living room equipment, you are asking for trouble. Alcohol also seems to effect people's better judgement and there's a theory drinking parties kill speakers. I had first hand experience with that once

http://sound.westhost.com/tweeters.htm
Alcohol literally, through that science crap, has been shown to make things sound quieter. Not a complex thing to put together.

Power is indeed what hurts speakers but you are not talking sbout anything close to 10 percent more power in heavily distorted sound. And literally, again via that science crap, what happens is higher harmonics are generated. Ten percent more power focused above the crossover could come close to doubling power to the tweeter (onaccounta tweeter range usually carries not much more than ten percent of total power. ) that could cause a problem.

To get those plateau thingies requires higher frequency harmonics. That's how it works. Not knowing that's how it works doesn't make it not so. You can watch harmonics flatten out a sine wave on you tube.

Similarly, not knowing the earth is not the center of the solar system does not change the sun's position at the center of the solar system.

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post #338 of 371 Old 07-21-2014, 06:03 PM
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Quote:
Originally Posted by M Code View Post
Lets kleer the air...
Clipping happens when a circuit is overdriven...
The circuit may be an input type like from a source component output level too high or an amplifier output stage. When an output stage is overdriven the amplifier sends out square waves which are very destructive to a loudspeaker, as they cause the motor structure of the loudspeaker (voice coil, magnet and gap) to heat up, twist and turn often destroying itself. Many users think that high output power is what destroys a loudspeaker...
But just the reverse is true, when a lowered power amplifier is pushed beyond its design limits it is more likely to generate the destructive square wave distortion. The square wave distortion destroys the loudspeaker, also note that many users are confused about a loudspeaker load to an amplifier, thinking it is just resistive..
To get a square wave you need odd harmonics adding up to forty percent distortion. Google it. Not a giant secret.

We say an amp is clipping at one percent distortion. A clipping amp just simply does not put out anything resembling a square wave. By a factor of roughly forty.

I have not seen thd for heavily clipping guitar amps, but if they are anywhere close to 40 percent distortion they just do not destroy the speakers in the guitar amp or the speakers in your stereo or the PA speakers at a concert that are reproducing that distorted signal.

The distortion does not kill speakers. Power kills speakers.
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post #339 of 371 Old 07-21-2014, 06:40 PM
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Quote:
Originally Posted by JHAz View Post
To get a square wave you need odd harmonics adding up to forty percent distortion. Google it. Not a giant secret.

We say an amp is clipping at one percent distortion. A clipping amp just simply does not put out anything resembling a square wave. By a factor of roughly forty.

I have not seen thd for heavily clipping guitar amps, but if they are anywhere close to 40 percent distortion they just do not destroy the speakers in the guitar amp or the speakers in your stereo or the PA speakers at a concert that are reproducing that distorted signal.

The distortion does not kill speakers. Power kills speakers.
U are very wrong...
One cannot set a 1% THD level as clipping..
Checkout the THD vs watts of any amplifier test report, in a solid state Class AB amplifier when it clips the THD goes straight up.. Regarding tube amplifiers it has far more gentle THD vs power output graph...
Note we are talking about home theater amplifiers not guitar amplifiers, as guitar amplifiers are actually designed for certain effects with distortion..

U better do more research....

Underpowered amplifier
A common and unfortunately dangerous situation...
As a precautionary measure or unfamiliarity with reality, many users choose an amplifier which is too low in power output...
At high volume levels it will clip and distort, it may supply direct current to the loudspeaker, which will destroy it. During clipping, a 40 Watt amplifier can reach > 100 Watts @ high THD in 1 millisecond....
As a sine wave is clipped, it starts to resemble (and sound like!) a square wave. A square wave is by definition the (infinite) sum of a fundamental frequency and its (EDIT: odd!) harmonics in definite proportion; thus it has a rich harmonic content. This harmonic content, which was not present in the input waveform, is harmonic distortion by definition. When an amplifier starts to clips the wave form gets distorted and squared off..

The attached chart will better explain this for U..

Next question..

Just my $0.03...
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post #340 of 371 Old 07-21-2014, 06:59 PM
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Quote:
Originally Posted by M Code View Post
U are very wrong...
One cannot set a 1% THD level as clipping..
Checkout the THD vs watts of any amplifier test report, in a solid state Class AB amplifier when it clips the THD goes straight up.. Regarding tube amplifiers it has far more gentle THD vs power output graph...
Note we are talking about home theater amplifiers not guitar amplifiers, as guitar amplifiers are actually designed for certain effects with distortion..

U better do more research....

Underpowered amplifier
A common and unfortunately dangerous situation...
As a precautionary measure or unfamiliarity with reality, many users choose an amplifier which is too low in power output...
At high volume levels it will clip and distort, it may supply direct current to the loudspeaker, which will destroy it. During clipping, a 40 Watt amplifier can reach > 100 Watts @ high THD in 1 millisecond....
As a sine wave is clipped, it starts to resemble (and sound like!) a square wave. A square wave is by definition the (infinite) sum of a fundamental frequency and its (EDIT: odd!) harmonics in definite proportion; thus it has a rich harmonic content. This harmonic content, which was not present in the input waveform, is harmonic distortion by definition. When an amplifier starts to clips the wave form gets distorted and squared off..

The attached chart will better explain this for U..

Next question..

Just my $0.03...
Ummm no. Some folks around here define clipping as the point at which the thd vs output curve hits the knee for increasing distortion. That is ususlly around .01 percent distortion. Any moron can go look at third party testing of amps by stereophile or whoever. One percent distortion is a common definition of clipping.

Any moron can google thd of a square wave. It is what it is. About forty percent thd.

Sorry. Reality is what it is.

And odd harmonics are not inherently more problematic than even harmonics. aND, shockingly, if the phase relationships aren't right you don't get a square wave even if the harmonics are in the right proportion. Omg! That squarewave horsecrap is horsecrap!

You need not believe this. The sun will remain at the center of the solar system despite your incomprehension.

Out.
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post #341 of 371 Old 07-21-2014, 07:00 PM
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I presume he means that 1% is considered, by convention only, the point at which THD might be audible and/or clipping is happening. It's just a convention, and I have read stuff before where people use that exact point.

As for the rest, I also don't consider square waves to be the issue, nor harmonics based on some well written articles, but I won't debate the point.

At the end of the day, power is what kills speakers. Clipping means more average power means more heat means possibly dead speaker drivers. Or you reached the mechanical limits, but that also means average power is too high.

I don't think anyone is debating the point that an amp with insufficient power increases chances of clipping which increases average power in ways speakers are not designed to handle but again the details are not too important - reduce power as needed and you should not be blowing speakers.

Personally I don't care for the logic of saying too little power kills speakers, because, taken at face value, the speakers insta-blow when the power to the amp is off But I know what people mean when they say it.

"But this one goes up to 11"
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post #342 of 371 Old 07-21-2014, 07:19 PM
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Quote:
Originally Posted by JHAz View Post
Ummm no. Some folks around here define clipping as the point at which the thd vs output curve hits the knee for increasing distortion. That is ususlly around .01 percent distortion. Any moron can go look at third party testing of amps by stereophile or whoever. One percent distortion is a common definition of clipping.

Any moron can google thd of a square wave. It is what it is. About forty percent thd.

Sorry. Reality is what it is.

And odd harmonics are not inherently more problematic than even harmonics. aND, shockingly, if the phase relationships aren't right you don't get a square wave even if the harmonics are in the right proportion. Omg! That squarewave horsecrap is horsecrap!

You need not believe this. The sun will remain at the center of the solar system despite your incomprehension.

Out.
Before U sign off for the outer limits..
Check closely the attached graph, it will better confirm your flawed definition that clipping @ 1% THD is bogus...
Check out the power output @ 1%THD, next check it out @ 10%THD, next check it out @ 20%THD...
In a solid state Class AB amplifier as the amplifier is pushed to its max output, power does not increase only the THD%..

Lights out..

Just my $0.03...
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post #343 of 371 Old 07-21-2014, 07:29 PM
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When members start referring to others as morons it's time to shut it down, no 2 cents required.
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post #344 of 371 Old 07-22-2014, 06:43 AM
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Quote:
Originally Posted by M Code View Post
Before U sign off for the outer limits..
Check closely the attached graph, it will better confirm your flawed definition that clipping @ 1% THD is bogus...
Check out the power output @ 1%THD, next check it out @ 10%THD, next check it out @ 20%THD...
In a solid state Class AB amplifier as the amplifier is pushed to its max output, power does not increase only the THD%..

Lights out..

Just my $0.03...

Here are a few thoughts for you. What destroys speaker voice coils is heat and heat is generated by power. The voice coil is not destroyed by the content of the signal but by the power it must dissipate in order to reproduce it. You can reproduce a square wave without any difficutly and it won't damage your speakers unless and until your speakers must dissipate more power and heat up to the point that wires in the voice coil break. You can download square waves on the internet and play then though your system and they won't hurt a thing. They won't sound pretty but they will play along just like anything else. The problems would only occur when too much power is dissipated and that would occur regardless of what the system is trying to reproduce.


Let me give you an example. I have a solid state guitar amplifier than can play a number of sound samples of distorted guitar. I can pick one that is horribly distorted and play it softly or loudly. It can't possibly be an issue until it is played loudly enough to overheat the voice coil of the speaker. In the case of that unit, it can play any of the samples at full volume without an issue. Why? Because it has an amplifier that is not capable of playing loud enough to break anything. The amp is not OVERpowered for the speaker.


An underpowered amplifier is never an issue because it can't supply enough current to destroy a voice coil. It is an over powered amplifier that has that capability. The underpowered amplifier could possible destroy its own output stage but it would require an overpowered amplifier to destroy a speaker voice coil.


Distortion doesn't hurt speakers. Power does that.
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post #345 of 371 Old 07-22-2014, 08:01 AM
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Quote:
Originally Posted by FMW View Post
Here are a few thoughts for you. What destroys speaker voice coils is heat and heat is generated by power. The voice coil is not destroyed by the content of the signal but by the power it must dissipate in order to reproduce it. You can reproduce a square wave without any difficutly and it won't damage your speakers unless and until your speakers must dissipate more power and heat up to the point that wires in the voice coil break. You can download square waves on the internet and play then though your system and they won't hurt a thing. They won't sound pretty but they will play along just like anything else. The problems would only occur when too much power is dissipated and that would occur regardless of what the system is trying to reproduce.


Let me give you an example. I have a solid state guitar amplifier than can play a number of sound samples of distorted guitar. I can pick one that is horribly distorted and play it softly or loudly. It can't possibly be an issue until it is played loudly enough to overheat the voice coil of the speaker. In the case of that unit, it can play any of the samples at full volume without an issue. Why? Because it has an amplifier that is not capable of playing loud enough to break anything. The amp is not OVERpowered for the speaker.


An underpowered amplifier is never an issue because it can't supply enough current to destroy a voice coil. It is an over powered amplifier that has that capability. The underpowered amplifier could possible destroy its own output stage but it would require an overpowered amplifier to destroy a speaker voice coil.


Distortion doesn't hurt speakers. Power does that.
Go back and read my posts..
We already covered the point about voice coils, heat....
When the loudspeaker's voice coil is overheated many things can happen...
Voice coil/form glue debonds
Voice coil deforms rubbing inside the gap
Voice coil excursion travels outside the gap

Regarding what destroys a loudspeaker power or distortion..
Also as posted previously (see the graph) when a solid state Class A-B amplifier is clipping @ high power output it generating high peaks of distortion plus milliseconds of high power.

About what destroys loudspeakers, power rather distortion..
Here again we disagree..
Kleen high power without distortion is far easier on a loudspeaker than low power with high distortion..
We can easily demonstrate this on virtually any loudspeaker, the crucial point depends upon the load the loudspeaker presents to the amplifier. If highly reactive (4 Ohms, 60 degrees) an amplifier rated @ 100W into an 8 Ohm resistor can decrease to 25W...
When an amplifier is being pushed hard to its limits, the chance of it clipping are very real..
Primary reasons is that the output devices within the amplifier are rated @ 65 degrees for its power output, but as heated up its efficiency drops big time...
As power output decreases, the user then increases its volume level driving the amplifier closer to its limits and going into clipping..

Just my $0.03...
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post #346 of 371 Old 07-22-2014, 10:47 AM
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I can't talk to sound quality because I've never tested them side by side but I can say that being able to replace just the pre/ pro in you system when it becomes obsolete is cheaper than having to by a whole new AVR. I've had my Marantz MM9000 for 12 years now as the primary amp in my system. It drives the hell out of my cambridge soundworks tower 2's. Ive gone through 3 perfectly working avr's in the same time period because the technology has advanced. Replacing just the pre/pro (I think) has saved me money. FWIW.
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post #347 of 371 Old 07-22-2014, 11:11 AM
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Quote:
Originally Posted by M Code View Post
Go back and read my posts..
We already covered the point about voice coils, heat....
When the loudspeaker's voice coil is overheated many things can happen...
Voice coil/form glue debonds
Voice coil deforms rubbing inside the gap
Voice coil excursion travels outside the gap

Regarding what destroys a loudspeaker power or distortion..
Also as posted previously (see the graph) when a solid state Class A-B amplifier is clipping @ high power output it generating high peaks of distortion plus milliseconds of high power.

About what destroys loudspeakers, power rather distortion..
Here again we disagree..
Kleen high power without distortion is far easier on a loudspeaker than low power with high distortion..
We can easily demonstrate this on virtually any loudspeaker, the crucial point depends upon the load the loudspeaker presents to the amplifier. If highly reactive (4 Ohms, 60 degrees) an amplifier rated @ 100W into an 8 Ohm resistor can decrease to 25W...
When an amplifier is being pushed hard to its limits, the chance of it clipping are very real..
Primary reasons is that the output devices within the amplifier are rated @ 65 degrees for its power output, but as heated up its efficiency drops big time...
As power output decreases, the user then increases its volume level driving the amplifier closer to its limits and going into clipping..

Just my $0.03...

I'm just trying to provide information. You don't have to accept it.
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post #348 of 371 Old 07-22-2014, 11:18 AM
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Quote:
Originally Posted by FMW View Post
I'm just trying to provide information. You don't have to accept it.
Thanx, no biggee..
Since we product development & sourcing for (2) of the more popular loudspeaker brands we have some insight and direct experience for this subject...

Just my $0.05..
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post #349 of 371 Old 07-22-2014, 01:31 PM
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Richard Clark wrote an article on it. I had posted the Rod Elliott article, but this is interesting as well -

http://www.monsterproducts.com/mpc/s...Some_Facts.pdf

Some of the key points. Music signals, even clipped are not going to become square waves. The exception might by synthesizers with square wave outputs, but those are imperfect square waves. I don't think any circuit can make true square waves as there's a limit to rise time.

Harmonics are explained as much lower in power, so not a major concern. Other articles I have read have made the same point.

This is the crux - "The real problem for our speaker is that any amplifier can produce more than its rated power if it is
allowed to distort and clipping is a sign that you have probably reached the point where you should turn
things down. To get a real picture of what the speaker sees compare Figures 12 and 13."

That's the bottom line, semantics aside. Clipping results in more power which kills speakers. Which is obviously why the horribly confusing phrase "too little power kills speakers" comes from. It would be clearer to say "Too little amplifier power can kill speakers due to too MUCH AVERAGE power to the speakers, which results from a higher chance of clipping" ( but that would be awkward to say, so I don't know how best to put it)
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post #350 of 371 Old 07-22-2014, 07:07 PM
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Originally Posted by M Code View Post
Before U sign off for the outer limits..
Check closely the attached graph, it will better confirm your flawed definition that clipping @ 1% THD is bogus...
Check out the power output @ 1%THD, next check it out @ 10%THD, next check it out @ 20%THD...
In a solid state Class AB amplifier as the amplifier is pushed to its max output, power does not increase only the THD%..

Lights out..

Just my $0.03...
I did not tell stereophile to use one percent as clipping. I got it from the hundred or so tests of theirs I have looked at. My understanding is it is used because its a sort of reasonable lowest level at which distortion is likely to be audible with at least one content. S'phile relaxes their standard to 3 percent for some tube amps. Nowhere nesr a square wave.

I simply don't see straight up after the knee in thd vs power charts. But I read How to Lie With Stastics 35 years ago when it was a 10 or 15 year old book and I could easily manipulate the x and y axes to make it look straight up if I wanted to. Doesnt change the fact that I have never seen such a chart that gets anywhere near square waves. Most of the more power is, uh, more power with a relatively slight addition from the clipping.

Eventualy more power will kill a speaker. But it is never distortion per se that does it. I could likely drive a preamp well past square waves if I hit it hard enough. Driving a 100 watt speaker with the maybe 5 watts the 12ax7s or line level opamps might max out at will never ever kill the speaker regardless of distortion level. Otoh hitting them with a couple hundred watts for a while likely would cook them whether the signal is distorted or not. Power kills.

The notion that an amp cannot make more power than its rating at .05 or .1 or even 1 percent distortion misapprehends how the things work. At ten percent distortion, though, the added power inherent in the distortion of the waveform is, I forget, but like 30 dB or so below the clean part of the signal. You can gogle thd percent distortion and identify my egregious errer for yourself but the bottom line will be the same. If -30 dB is correct, the distortion is one one thousandth of the total power. It just seems likely the other, non distortion related 99.999 percent of the power is the killer, not the distortion.

But hey that's just me being rational and crap.
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post #351 of 371 Old 07-22-2014, 07:38 PM
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Originally Posted by JHAz View Post
I did not tell stereophile to use one percent as clipping. I got it from the hundred or so tests of theirs I have looked at. My understanding is it is used because its a sort of reasonable lowest level at which distortion is likely to be audible with at least one content. S'phile relaxes their standard to 3 percent for some tube amps. Nowhere nesr a square wave.

I simply don't see straight up after the knee in thd vs power charts. But I read How to Lie With Stastics 35 years ago when it was a 10 or 15 year old book and I could easily manipulate the x and y axes to make it look straight up if I wanted to. Doesnt change the fact that I have never seen such a chart that gets anywhere near square waves. Most of the more power is, uh, more power with a relatively slight addition from the clipping.

Eventualy more power will kill a speaker. But it is never distortion per se that does it. I could likely drive a preamp well past square waves if I hit it hard enough. Driving a 100 watt speaker with the maybe 5 watts the 12ax7s or line level opamps might max out at will never ever kill the speaker regardless of distortion level. Otoh hitting them with a couple hundred watts for a while likely would cook them whether the signal is distorted or not. Power kills.

The notion that an amp cannot make more power than its rating at .05 or .1 or even 1 percent distortion misapprehends how the things work. At ten percent distortion, though, the added power inherent in the distortion of the waveform is, I forget, but like 30 dB or so below the clean part of the signal. You can gogle thd percent distortion and identify my egregious errer for yourself but the bottom line will be the same. If -30 dB is correct, the distortion is one one thousandth of the total power. It just seems likely the other, non distortion related 99.999 percent of the power is the killer, not the distortion.

But hey that's just me being rational and crap.
U continue to debate reality even though it is displayed to U with graphs and substantiation by credible sources..
The last time U challenged my explanations about output power in another thread U were going to research and present some examples of test reports that backed up your claims..
Onkyo all channel driven?

To date, nothing has been received..

So we are moving on as this thread has run its course... Lights out..

Just my $0.03...
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post #352 of 371 Old 07-22-2014, 08:12 PM
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Quote:
Originally Posted by M Code View Post
U continue to debate reality even though it is displayed to U with graphs and substantiation by credible sources..
The last time U challenged my explanations about output power in another thread U were going to research and present some examples of test reports that backed up your claims..
Onkyo all channel driven?

To date, nothing has been received..

So we are moving on as this thread has run its course... Lights out..

Just my $0.03...
Sh. So you cannot comprehend the charts you read. Cannot see what the questiondcare.

Thd has like an actual scientific meaning, dude. I misrenenbered. Ten percent thd means the distortion products are 20 dB below the main signal. Every ten dB is, by definition , a power factor of 10. So a 100 watt output at ten percent distortion includes distortion products by definition at one watt. If the distortion was more than one watt thd would be higher. I tend to believe its the 99 watts, not the one watt, that are the issue.

Perhaps you want to imagine these defined terms nean something different, like in the novek 1984, I just don't know.

Simply is what it is. I lack the mindreading capabilities to see where these simple facts get past you but obviously they do. In the end it is grade school math math I can't fix an inability to add and subtract.

And ftr your arcam results show ten percent distortion just barely ubder 200 watts which is consistent with what I have been saying. so 2 watts of that is distortion and the rest is not distortion. By definition of the terms used.

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Originally Posted by FMW
Just my $0.03..
Quote:
Originally Posted by M Code View Post
Just my $0.05..
HOLD down <ALT> then press 0 1 6 2

Just my 2¢
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Part of the difficulty, for a long time for me, and clearly for others, in assessing distortion is the coplete (to me) counterintuitive (not to say utter incompatibility with comon sense) of the fact that complex waves are made up of a whole bunch of sine waves in specific relationships to each other. SO, despite the fact it makes no immediate sense to me, truth is that a square wave consists of a fundamental plus odd harmonics. If the voltage of the fundamental is V, then the third harmonic (H#) is 1/3 of V, the fifth harmonic is 1/5 of V, the seventh harmonic is 1/7 of V, etc. (Note that because of ohm's law, one third voltage connotes less than one third power).

Note that since, AFAIK, no amp in the world produces only odd harmonics when distorting, the even harmonics will make it impossible for the amp to ever actually produce a square wave, because a square wave contains no even harmonics.

The notion that complex waves are made up of sine waves is not new stuff. People ascribe it to J Fourier, a French ella who lived rom 1768 – 1830. So it ain't new stuff. A pretty good tutorial, with oscilloscope demonstrations etc of this with respect to a square wave is at
.

As a practical matter, those power-versus-THD plots we've seen above and in hundreds of amp tests come from application of a technology called FFT, which stands for Fast Fourier Transform. IOW, the test results depend, in an absolute way, on the accuracy of the Fourier concept that complex waves are made up of sine waves. If the underlying theory that the wave is made up of many sine waves is wrong, then whatever an FFT spits has to be wrong, too. So it would be pointless to continue discussing those meaningless results.

Moreover, AIUI, digital sound relies on FFT to recreate audio from the digital representation. So if the complex waves on CDs, or in the sound of things we get off the internet, are not composed of a series of sine waves, then the entire world has been laboring under a massive delusion that we actually get sound from CDs or off the internet. Not possible, if the underlying theory is wrong. Yet, I seem to hear sound when I play a CD, or when I watch things on youtube. Tends to make it likely that the theory is correct.

For me, seeing with my own eyes a sine wave transform toward a square wave on a scope as the higher harmonics are added made the concept, if not intuitive, at least concrete. I'm no longer uncomfortable with it . . .

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Then don't take the bait.

But -- with respect -- the members starting the subsequent harassment don't have any blame in this, whatsoever? It is our responsibility to not take the bait...but they are permitted to create the bait?

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I am saying i learned ohm's law in school when i was 12 ot 13 years old, and so did everybody in the class. It does not require high levels of technical competence to grasp. A decision not to try to grasp it seems like an intentional refusal to understand the basics so reality doesn't interfere with hanging onto beliefs that cannot be true.




Quote:
And ftr i thought for longer than i would care to admit that somehow the greater power would make a difference even in low power situations. I was silly and perhaps viewing speakers anthropomorphically, like they could see or feel or smell or taste the added power in the amp. I wuz full o shite.

Big power is only needed when it is needed. Big rooms, long distances to speakers, inefficient speakers, high peak levels may require high power. Peaks are a bitch even if they only last a twentieth of a second. A 20 dB peak requires 100 times the power of the average. Whether the speaker can reproduce the peak without distortion or compression also enters into what you hear. I believe but could not prove my little paradigms plus sub could cleanly hit peaks at 95dB or so (consistent with my real listening levels) but I would not even bet five bucks they can do 105 dB, as required for reference level.

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post #357 of 371 Old 07-27-2014, 04:43 PM
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Hello Rico, and thank you for your continued assistance/input...


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Originally Posted by Ricoflashback View Post
I think I understand what you are trying to accomplish. But I believe you said that your Onkyo 605 does not have preouts? (Is it this model - TX-SR605S - 7.1 90 wpc?) If you try to use a line level converter - - you might be limited to 60 watts per channel (or some number like that) I am unfamiliar on how well this will work - - especially if you add different amplifier sources to the mix.

Yes -- the model is the TX-SR605(B) and it does NOT have preamp outputs...I was thinking of adding on a "line converter" device which would transform my speaker-level outputs to preamp outputs (as these devices do with factory car stereos) so I COULD add an amp to this receiver, but I don't know what effect that would have on sound quality. I'm not sure what you mean by "you might be limited to 60 watts-per-channel" when you replied about the line converter; wouldn't the converter be a mere "sendoff" device to feed an external muscle amp?

Quote:
Now - - here comes the real question and the crux of this whole thread - - separates versus an integrated AVR. Most integrated, multichannel AVRs will go up to 120 wpc. I'm sure some higher end models might go higher but they are expensive. I do not see much of a difference between 90 wpc and 120 wpc. Hence the argument for separates IF you believe more power will benefit your situation.

Yes -- I understand that, thus why I was considering using a new AVR just to power the "less demanding" surround channels of the system while letting an external power amp power either the main two Polk RTi12s or the front three channels altogether in a three-channel model...my question was do you think a new AVR's amp section would be powerful enough for JUST powering surround channels? I don't see why they wouldn't be, especially since I have small-ish in-ceiling SpeakerCraft models...

Quote:
Many folks in this thread will tell you that you don't need to do anything - - 90 wpc per channel is more than adequate.

It seems so, based on what I'm experiencing now -- but I wanted to experiment with extra power to see what my RTi12s can "really do" if you know what I mean, or to have the reserve wallops of wattage available if/when they're ever called upon...

Quote:
Lastly - - if two channel stereo is important to you, many multichannel AVR's skimp on the analog outputs. They just do not sound very good. Hence, my purchase of the Parasound 2100 stereo preamplifier to round out my HT. I was listening to Steve Winwood last night (Arc of a Diver - Spanish Dancer and Night Train.) With the Parasound 2100 (via my OPPO 103 Bluray Player - analog outputs) - - and listening in two channel mode - - it sounded like my subwoofer was engaged! It wasn't. Great soundstage and nice, tight thump to the bass.

To me - - that's where the extra power comes in to play.

In closing - - my setup is complete. The only replacement in the future will be a "Preamp." For 4K video and possible Dolby Atmos. But that is four to five years a way.

I hope this helps.

I have a separate two-channel dedicated system in another room from my 5.1 surround rig, also powered by an Onkyo (stereo receiver) so two-channel isn't a priority in the system in question (the one with the Onkyo 605/Polk RTi12 setup).


With regard to your comment about Dolby Atmos -- can you give me some more specifics about this algorithm? Info and specs have been spotty in my neck of the woods; is this something that needs to be implemented with 4K media? I know Onkyo has this in their new AVRs, but how exactly does Atmos work...is it a "matrix spreading" system like Pro Logic II or is it an actual format that we're going to see on 4K discs if/when they ever arrive?

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post #358 of 371 Old 07-31-2014, 03:58 AM
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Sorry I didn't get back earlier as I've been traveling for my work.

RE: Yes -- the model is the TX-SR605(B) and it does NOT have preamp outputs...I was thinking of adding on a "line converter" device which would transform my speaker-level outputs to preamp outputs (as these devices do with factory car stereos) so I COULD add an amp to this receiver, but I don't know what effect that would have on sound quality. I'm not sure what you mean by "you might be limited to 60 watts-per-channel" when you replied about the line converter; wouldn't the converter be a mere "sendoff" device to feed an external muscle amp?

I have read that there are some limitations on line converters - - so my suggestion is to research what you would be buying and see if this is true.

RE: With regard to your comment about Dolby Atmos -- can you give me some more specifics about this algorithm? Info and specs have been spotty in my neck of the woods; is this something that needs to be implemented with 4K media? I know Onkyo has this in their new AVRs, but how exactly does Atmos work...is it a "matrix spreading" system like Pro Logic II or is it an actual format that we're going to see on 4K discs if/when they ever arrive?

There is a whole thread on Dolby Atmos. You'll obviously need to have additional speakers and the AVR will need to process the channels. I do not believe this is "matrix spreading" as it should be discrete channels. Very new technology and not a lot of experience in a home theater environment yet. Hope this helps.

Home Theater Setup
Samsung UN65ES8000 LCD/LED
BenQ W1080ST Projector
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Wyred4Sound MMC-7 Channel Amplifier, 221wpc
OPPO 103, Directv GENIE
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post #359 of 371 Old 07-31-2014, 04:29 AM
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Quote:
Originally Posted by MichaelJHuman View Post


This is the crux - "The real problem for our speaker is that any amplifier can produce more than its rated power if it is
allowed to distort and clipping is a sign that you have probably reached the point where you should turn
things down.

That's the bottom line, semantics aside. Clipping results in more power which kills speakers. Which is obviously why the horribly confusing phrase "too little power kills speakers" comes from. It would be clearer to say "Too little amplifier power can kill speakers due to too MUCH AVERAGE power to the speakers, which results from a higher chance of clipping" ( but that would be awkward to say, so I don't know how best to put it)
that being said

you are making the case for a better amp section/power supply

ie...higher levels of output with extremely low distortion

right?

the only way to receive that is when a higher end unit...be it a better AVR or a high end separate amp


Warren

Rm 1 Samsung 64F8500 Onkyo 5508 prepro Sherbourn 5/1500A amp Atlantic technology System 350 THX Ultra speakers
Rm 2 LG 47LE8500 Pioneer SC37 Celestion 305 speaker system
Rm 3 Samsung 51E8000 Yamaha A2010 Kef 2005.2 speaker system
Rm 4 Panasonic 50ST50 Onkyo 5009/906 Mirage Omni sat speaker system
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post #360 of 371 Old 07-31-2014, 08:50 AM
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That was not my point, but of course buying an amp/receiver with more power will let you hit higher SPL without clipping. But as mentioned frequently, you do have to double the power for appreciably more SPL.

The finances of buying double the power is a bit discouraging for people because you need double the power. If I needed double the power of a 100 watt receiver, I would need 200 watts. It's possible the 100 watt receiver can't hit that peak with real world signals, I don't know the answer, but I suspect mid range receivers can, as a general rule. So if I spend $700 for a receiver with pre outs I have to spend $1000 for a 200x5 watt amp. Over twice as much for 3 dB SPL gain.

Of course there's other factors like low impedance capability to consider. It's reasonable to think better than a 3 dB gain will be had with the external amp due to it's better performance into lower impedance loads and the fact 8 ohm speakers are not purely 8 ohm.

"But this one goes up to 11"

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