"Official" All amps sound the same thread - Page 25 - AVS Forum
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post #721 of 2642 Old 04-19-2009, 07:43 AM
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Originally Posted by jpaik View Post

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push back against dubious claims that defy logic;
be on the lookout for misrepresentations;
question the lack of science when belief is the substitution;
be very skeptical when the denial of the laws of physics comes into play.

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Mind if I use that for a signature line?

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post #722 of 2642 Old 04-19-2009, 07:45 AM
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Originally Posted by moonhawk View Post

I think Janeane Garofolo is the new poster child for that sort of demagoguery.

Other than that, I more or less come down on the same side as you; i.e. it's not the message of the "all amps sound the same" crowd, it's the tactics and arrogance that bug me.

Debate the message, not the messenger!

You may not like me, I do not care because this is not a popularity contest or a friendship forum, we have enough friends in the real world (I would think). My points do not butter anyone up, they are blunt and simple, I will call out ignorance where I see it.

Try and argue the facts, is that too much to ask for.

Unlike you guys, I do not reply with name calling. I really wonder why that is....something about education, etc

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post #723 of 2642 Old 04-19-2009, 07:51 AM
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Originally Posted by exm View Post

Some background... I went from the Para 2205 to the Outlaws and back to the Halos (for a good reason). The only reason I got rid of the 2205 was because of the massive heat generation, but I really felt sound wise I downgraded. The Outlaws aren't bad, but seriously lacked any punch/dynamics. Moving up to the Halos restored the sound I was used to.

Since I own them all, Please show me the measurements that back up your opinion?

Outlaw 2200 did not lack punch/dynamics.....nor did the para 2205 give such a great puch/dynamics. As I said, show me the data difference and I have $$$ for you!

Im cool with people thinking there is a difference in their own little world but when this stuff is posted online, it misleads people.

If you guys spend so much money on speakers equipment, why not spend $200 on measuring equipment and find out the truth about the differences.

Dynamics/punch/bright/detailed....and so on all have measurements to back them up. Why not give opinion validation? Why not actually learn something more about your own systems and what the differences look like on paper, in a graph?

You can say you do not care and that is also cool but then why even post on a AV Science forum about it?? It just seems to me that people do care and they are just too stubborn to admit they might have been wrong for years and years.

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post #724 of 2642 Old 04-19-2009, 08:04 AM
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Originally Posted by moonhawk View Post

I think Janeane Garofolo is the new poster child for that sort of demagoguery.

... it's the tactics and arrogance that bug me.

I realize that you are equating belittling communication styles, but one had more of an impact on our last election than the other and I agree perceived "tactics and arrogance" played an important role in the outcome. ;-)

Insofar as this thread is concerned, I agree with the posters that feel lower impedance speakers is where the difference of amps (and available power supplies) comes into play...
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post #725 of 2642 Old 04-19-2009, 08:13 AM
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Originally Posted by Zen Traveler View Post

I realize that you are equating belittling communication styles, but one had more of an impact on our last election than the other and I agree perceived "tactics and arrogance" played an important role in the outcome. ;-)

Insofar as this thread is concerned, I agree with the posters that feel lower impedance speakers is where the difference of amps (and available power supplies) comes into play...

More of a straw dog argument type of thing.

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post #726 of 2642 Old 04-19-2009, 08:22 AM
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Originally Posted by penngray View Post

Debate the message, not the messenger!

You may not like me, I do not care because this is not a popularity contest or a friendship forum, we have enough friends in the real world (I would think). My points do not butter anyone up, they are blunt and simple, I will call out ignorance where I see it.

Try and argue the facts, is that too much to ask for.

Unlike you guys, I do not reply with name calling. I really wonder why that is....something about education, etc

Penn

I have no dislike of you whatsoever, and my post was not referring to anyone specific. Nor did I call anyone any names, don't know why I was accused of that. I have in fact reached out to you to inquire about your DIY speakers, because I built my own as well, and I never got a reply. That's OK, just want to say I'm not here to piss anyone off.

And I don't necessarily disagree with you. I have far less experience with HT stuff than many here do.

Sometimes the science crowd has a very dismissive attitude towards those with whom they disagree, and that bothers me. There are countless historic examples of "science" being wrong, or motivated for the wrong reasons. That is why I try to keep an open mind. It probably works both ways. I have certainly learned a lot from both sides, and that is why I'm here.

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post #727 of 2642 Old 04-19-2009, 08:31 AM
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Quote:
Originally Posted by penngray View Post

Debate the message, not the messenger!

You may not like me, I do not care because this is not a popularity contest or a friendship forum, we have enough friends in the real world (I would think). My points do not butter anyone up, they are blunt and simple, I will call out ignorance where I see it.

Try and argue the facts, is that too much to ask for.

Unlike you guys, I do not reply with name calling. I really wonder why that is....something about education, etc

penny, what do you achieve with these continuous pompous insulting posts?
It is beyond reason why one would do this.
I realize it gives you a false sense of superiority but don't you realize that you are exposing a rather fragile side of yourself in so doing?
Just stick to the thread without the barbs. I mean this sincerely.

Elwood P. Dowd: Years ago my mother used to say to me, she'd say, "In this world, Elwood, you must be" - she always called me Elwood - "In this world, Elwood, you must be oh so smart or oh so pleasant." Well, for years I was smart. I recommend pleasant. You may quote me.
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post #728 of 2642 Old 04-19-2009, 08:33 AM
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Quote:
Originally Posted by penngray View Post


If you guys spend so much money on speakers equipment, why not spend $200 on measuring equipment and find out the truth about the differences.

Dynamics/punch/bright/detailed....and so on all have measurements to back them up. Why not give opinion validation? Why not actually learn something more about your own systems and what the differences look like on paper, in a graph?

I downloaded REW a couple of weeks ago, but then got caught up with taxes and events that I was responsible for and want to get back to this endeavor...I have a rat shack meter and will check what patch cords I need, but is there anything else I should consider?
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post #729 of 2642 Old 04-19-2009, 08:35 AM
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Originally Posted by moonhawk View Post

I think Janeane Garofolo is the new poster child for that sort of demagoguery.

Other than that, I more or less come down on the same side as you; i.e. it's not the message of the "all amps sound the same" crowd, it's the tactics and arrogance that bug me.

My post in no way was meant to introduce politics or state a political preference. Janeane Garofolo would have been just as good a choice to have made my point.

Elwood P. Dowd: Years ago my mother used to say to me, she'd say, "In this world, Elwood, you must be" - she always called me Elwood - "In this world, Elwood, you must be oh so smart or oh so pleasant." Well, for years I was smart. I recommend pleasant. You may quote me.
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post #730 of 2642 Old 04-19-2009, 08:43 AM
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Originally Posted by moonhawk View Post


Sometimes the science crowd has a very dismissive attitude towards those with whom they disagree, and that bothers me. There are countless historic examples of "science" being wrong, or motivated for the wrong reasons. That is why I try to keep an open mind. It probably works both ways.

I agree about keeping an open mind, but when science is "proved" wrong their peers tend to agree whereas in the more subjective field that I feel you are referring they just start another branch that supports their "beliefs."
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post #731 of 2642 Old 04-19-2009, 08:57 AM - Thread Starter
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I have been trying to understand a concept we discuss here a lot. That concept is peak levels vs. average levels.

I could use some help.

I have written a WAV file reader. I know how to calculate RMS. What I don't know, is how to figure out average and peak levels which are meaningful to consumed power.

A WAV file sampled from a CD contains sample values from -32768 to 32767 (16 bit samples.) There are actually two samples per sample period for each channel, left and right.

I don't know how a DAC works precisely. My guess is that these will be linearly converted to a voltage range. For argument sake, let's say -1 to +1 volt.

Ignoring any gain stages in between, let's say we directly amplify that voltage to a range from -30 to +30 volts. My understanding is that the power transistors should roughly draw power equal to v ^ 2 / 8. That is voltage squared divided by 8 ohms, assuming nominal ohm draw. I am not sure if that's good enough for analysis, but that's all I know how to do.

Using this same logic, peak power would occur at peak voltage. If I note the peak signal level, I would hope that's good enough, but I am not sure.

So my questions are -

1) For a rough guess at average level, is it sufficient to calculate the RMS of the signal level?
2) For a rough guess at peak level, is it sufficient to calculate the peak signal value?
3) Once I have calculate RMS average level and peak signal value, do I then apply the dB formula using a factor of 20 to calculate peak vs average in dB?

Applying all of this thinking to the song Closer by NIN, I get these values. Peak signal level is approximately 32000, or pretty close to clipping as we would guess. Average RMS signal level is 6600. Calculating dB using a factor of 20 ( 20 * log( ps / as) yields approx. 13 dB.

That seems to be in the ballpark. But I feel I don't know enough about the subject and welcome any input.

"But this one goes up to 11"
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post #732 of 2642 Old 04-19-2009, 09:21 AM
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Originally Posted by Zen Traveler View Post

I agree about keeping an open mind, but when science is "proved" wrong their peers tend to agree whereas in the more subjective field that I feel you are referring they just start another branch that supports their "beliefs."

Not really what is happening here. The people claiming that science is on their side have inadvertently "rigged" their test to produce the results they want.
That is the frustration, the same "science" using different controls yields different results. Hence, the controversy.
No one here that I am aware of does not believe in science it is the absoluteness of the one set of controls that is not agreed on..

Elwood P. Dowd: Years ago my mother used to say to me, she'd say, "In this world, Elwood, you must be" - she always called me Elwood - "In this world, Elwood, you must be oh so smart or oh so pleasant." Well, for years I was smart. I recommend pleasant. You may quote me.
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post #733 of 2642 Old 04-19-2009, 09:23 AM
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I imagine you've seen the white paper from Crown, "How much amplifier power do I need?" In the peak headroom section, it states how to use their calculator (and gives the formula they use)...

http://www.crownaudio.com/apps_htm/d...ct-pwr-req.htm

Peak headroom

Because music has transient peaks that are 6 to 25 dB above the average level, the power amplifier needs to produce enough power to handle those peaks without distortion.
For example, if you need 100 watts continuous power to achieve the desired average SPL, you need 1,000 watts continuous to handle 10 dB peaks, 3,162 watts to handle 15 dB peaks, and 10,000 watts to handle 20 dB peaks. Clearly, the peaks require far more power than the average levels. In the calculator's Peak Headroom field, enter 6 dB for rock music that is compressed or limited, or enter 20 to 25 dB for uncompressed live music. If you can live with some short-term clipping which may be inaudible, enter 10 to 15 dB.
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post #734 of 2642 Old 04-19-2009, 09:26 AM - Thread Starter
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Originally Posted by MLKstudios View Post

I imagine you've seen the white paper from Crown, "How much amplifier power do I need?" In the peak power section, it states how to use their calculator (and gives the formula they use)...

http://www.crownaudio.com/apps_htm/d...ct-pwr-req.htm

Peak headroom

Because music has transient peaks that are 6 to 25 dB above the average level, the power amplifier needs to produce enough power to handle those peaks without distortion.
For example, if you need 100 watts continuous power to achieve the desired average SPL, you need 1,000 watts continuous to handle 10 dB peaks, 3,162 watts to handle 15 dB peaks, and 10,000 watts to handle 20 dB peaks. Clearly, the peaks require far more power than the average levels. In the calculator's Peak Headroom field, enter 6 dB for rock music that is compressed or limited, or enter 20 to 25 dB for uncompressed live music. If you can live with some short-term clipping which may be inaudible, enter 10 to 15 dB.

My goal is not to accept at face value what Crown states, but to independently gain some knowledge myself as to what reasonable peak vs average power draw is. It's in Crown's best interests for you to buy a bigger amp than you need

"But this one goes up to 11"
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post #735 of 2642 Old 04-19-2009, 09:33 AM
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Originally Posted by MichaelJHuman View Post

I have been trying to understand a concept we discuss here a lot. That concept is peak levels vs. average levels.

I could use some help.

I have written a WAV file reader. I know how to calculate RMS. What I don't know, is how to figure out average and peak levels which are meaningful to consumed power.

A WAV file sampled from a CD contains sample values from -32768 to 32767 (16 bit samples.) There are actually two samples per sample period for each channel, left and right.

I don't know how a DAC works precisely. My guess is that these will be linearly converted to a voltage range. For argument sake, let's say -1 to +1 volt.

Ignoring any gain stages in between, let's say we directly amplify that voltage to a range from -30 to +30 volts. My understanding is that the power transistors should roughly draw power equal to v ^ 2 / 8. That is voltage squared divided by 8 ohms, assuming nominal ohm draw. I am not sure if that's good enough for analysis, but that's all I know how to do.

Using this same logic, peak power would occur at peak voltage. If I note the peak signal level, I would hope that's good enough, but I am not sure.

So my questions are -

1) For a rough guess at average level, is it sufficient to calculate the RMS of the signal level?
2) For a rough guess at peak level, is it sufficient to calculate the peak signal value?
3) Once I have calculate RMS average level and peak signal value, do I then apply the dB formula using a factor of 20 to calculate peak vs average in dB?

Applying all of this thinking to the song Closer by NIN, I get these values. Peak signal level is approximately 32000, or pretty close to clipping as we would guess. Average RMS signal level is 6600. Calculating dB using a factor of 20 ( 20 * log( ps / as) yields approx. 13 dB.

That seems to be in the ballpark. But I feel I don't know enough about the subject and welcome any input.

This is perfectly correct.
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post #736 of 2642 Old 04-19-2009, 09:44 AM - Thread Starter
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Originally Posted by fyzziks View Post

This is perfectly correct.

Seems to be, but what do I know. I am a software guy, not an electrical engineer

I have been digging through my copy of the classic Sound Reinforcement Handbook, and they seem to claim a standard headroom of 20 dB.

I am going to rip some more songs to WAV files, and try to find one with a 20 dB peak to RMS value. At the moment, I am still sick with some stomache bug, so it might take a bit to come up with some values.

Today's rock CDs and maybe pop CDs should have lower peak to average level due to the amount of compression used. So I will try to find some CDs mfg'd in the 80s.

"But this one goes up to 11"
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post #737 of 2642 Old 04-19-2009, 10:20 AM
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Originally Posted by MKtheater View Post

Yes, but even Medicine at one point called everything quackery that was not medicine. We learn new things on a daily basis and should keep an open mind. I do believe that amps sound more similar than different but sometimes there are differences.

But no one says all amps sound the same. No one says any amp can drive any load at any level. The conditions under which amps will sound different are known.

They just aren't 'exciting' enough for kooky audiophile culture. So kooky audiophiles -- and I am not saying you are one, I'm referring to the Stereophile/Abosolute Sound reviewer-types -- invent reasons why amps sound different, and florid vocabularies to describe these differences, all based on a misplaced confidence that whatever they THINK they hear , must be real. To the kookiest of them, science can *never* prove they are wrong about that.
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post #738 of 2642 Old 04-19-2009, 10:23 AM
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Originally Posted by MichaelJHuman View Post

Seems to be, but what do I know. I am a software guy, not an electrical engineer

Well, I am a EE, and I say you're right. For whatever that's worth.
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Today's rock CDs and maybe pop CDs should have lower peak to average level due to the amount of compression used. So I will try to find some CDs mfg'd in the 80s.

Maybe some less compressed stuff, like jazz or classical, would be good to try.
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post #739 of 2642 Old 04-19-2009, 10:25 AM
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Originally Posted by Zues View Post

Like anything else, all amps are different.


How about a digital copy of a digital file?

Do new words appear in your Word documents every time you copy them?
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post #740 of 2642 Old 04-19-2009, 10:32 AM
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Originally Posted by eljr View Post

penny, what do you achieve with these continuous pompous insulting posts?
It is beyond reason why one would do this.
I realize it gives you a false sense of superiority but don't you realize that you are exposing a rather fragile side of yourself in so doing?
Just stick to the thread without the barbs. I mean this sincerely.

Your own posting history shows you're a hypocrite, eljr. You affect to be superior to what you jeer at as a 'flat earth' or 'flat line' (you seem confused about the two) contingent -- what in a more neutral audiophile parlance would be called 'objectivists'. You toss barbs. You are pompous and insulting.

So what, exactly are you complaining about? That you get as good, or better, than you give?
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post #741 of 2642 Old 04-19-2009, 10:33 AM - Thread Starter
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Jazz and Classical? Ack. I don't listen to stuff like that Well, sometimes, but not often, and I own few discs in those genres.

How about something from the Star Wars soundtrack? It's orchestral

"But this one goes up to 11"
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post #742 of 2642 Old 04-19-2009, 10:35 AM
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Quote:
Originally Posted by MichaelJHuman View Post

My goal is not to accept at face value what Crown states, but to independently gain some knowledge myself as to what reasonable peak vs average power draw is. It's in Crown's best interests for you to buy a bigger amp than you need

Yes...those big, evil corporations wanting to shaft us so we will keep coming back for more of their products.

More seriously, consider that they merely want to sell you an amp that is right for your needs. Perhaps you should pay a visit to the Crown or QSC forums and see what kind of amplifier advice is being given. I can assure you they're not recommending IT 8000s and PL 380s to everyone that asks what amp they need to drive a pair of SOS.

I think you're reinventing the wheel, but I guess as long as it fixes something you're not clear on it's all good.

Live sound vs recorded sound crest factor/PAR are almost certainly going to be much different, I'd suspect.

Just because there is a knob doesn't mean you should turn it.
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post #743 of 2642 Old 04-19-2009, 10:37 AM
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Originally Posted by Zen Traveler View Post

I agree about keeping an open mind, but when science is "proved" wrong their peers tend to agree whereas in the more subjective field that I feel you are referring they just start another branch that supports their "beliefs."

+1

There is an old saying about how it's good to keep an open mind, but not so open that your brains fall out.

I find that often those calling for an 'open mind' about something are ignorant of what already HAS been discovered and 'proved' to the satisfaction of scientists, and the evidence behind that belief.

Does it really makes sense, for example, to those who aren't aware that I=V/R to claim to have an 'open mind' about cable difference?

The best scientific open minds are the ones who have all the 'current' facts at their disposal, and can come up with a new model explaining them, or can see where there's a hole in them. THOSE are the people scientists respect, not the crackpots who quickly prove they don't even have the fundamentals down in the first place.
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post #744 of 2642 Old 04-19-2009, 10:57 AM - Thread Starter
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Originally Posted by whoaru99 View Post

I think you're reinventing the wheel, but I guess as long as it fixes something you're not clear on it's all good.

I think the problem is that dynamic range figures are given with no validation whatsoever. No reference to any papers or other research on the topic. If they gave me a reference to something I could read, I would read it. But because I have yet to see any concrete data on dynamic range, I felt it would be best to do my own research to the best of my abilities.

In that sense, I don't see this as reinventing the wheel. There is no wheel, there's just a bunch of people asserting that they are aware of a wheel, but can't or won't show it to you

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post #745 of 2642 Old 04-19-2009, 10:58 AM
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Quote:
Originally Posted by extigr View Post

But no one says all amps sound the same. No one says any amp can drive any load at any level. The conditions under which amps will sound different are known.

They just aren't 'exciting' enough for kooky audiophile culture. So kooky audiophiles -- and I am not saying you are one, I'm referring to the Stereophile/Abosolute Sound reviewer-types -- invent reasons why amps sound different, and florid vocabularies to describe these differences, all based on a misplaced confidence that whatever they THINK they hear , must be real. To the kookiest of them, science can *never* prove they are wrong about that.


Question:
What percentage of the population must be able to discriminate between two amps in a double blind test, for the amps to be considered "different"? If only 100 'golden eared' audio industry reviewers can tell the difference, I clearly don't care personally, but, for the purposes of this thread, it begs the question: Are 100 people who can hear a difference [out of 6 billion] enough to define two amps as different? How about 10 people? How about ONE person? [...and what happens when that person dies?]

Is there some existing quantification of the term 'different' which is useful in this context?

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post #746 of 2642 Old 04-19-2009, 11:06 AM
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To really hear how an amp sounds, wouldn't you need to unhook the speakers that could color it? Maybe one hums better than another?
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post #747 of 2642 Old 04-19-2009, 11:30 AM
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Originally Posted by MichaelJHuman View Post

Jazz and Classical? Ack. I don't listen to stuff like that Well, sometimes, but not often, and I own few discs in those genres.

How about something from the Star Wars soundtrack? It's orchestral

Actually, film music is probably a very good choice - there's a lot of excellent stuff in that genre. Lots of dynamics, full spectral range, and some really good music to boot.
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post #748 of 2642 Old 04-19-2009, 11:44 AM - Thread Starter
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Originally Posted by fyzziks View Post

Well, I am a EE, and I say you're right. For whatever that's worth.

Maybe some less compressed stuff, like jazz or classical, would be good to try.

Largest peak to average level I have found so far is just under 15 dB.

I also wonder how useful some orchestral music files would be. Bolero, for example has a slow buildup, and likely has a misleading average level because of it. The peaks would occur later in the piece, with the earlier part of the piece driving the average level down.

Anyway, based on my limited checks of some tracks, 15 dB seems like a reasonable peak to average level for music I listen to based on the above post I made on this topic.

I believe that's a factor of 32 between average and peak power draw. That alone does not tell the whole story, because brief peaks could likely be handled by drawing from the power supply caps. I have no information on how much of an affect that is, so I will stick with a factor of 32.

Given a listening position 4 meters away, we lose 12 dB. We can add 3 dB back in most likely due to having two speakers and using a powered sub. ( best guess I can make knowing what I know.)

Assuming an average level of 85 dB (pretty loud, IMO,) and add 9 dB to make up for losses, we need to push approx 95 dB one meter away from one of the speakers.

Assuming speakers with a sensitivity of 90 dB, we need approx. 4 watts of power on average. That gives us 128 watts peak (4 * 32.)

If all of this is not a lot of BS, I can see where it's possible that some receivers can't even do 85 dB average levels without risking clipping. Be nice if I had an oscilloscope to do some better testing.

"But this one goes up to 11"
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post #749 of 2642 Old 04-19-2009, 11:48 AM
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Originally Posted by MichaelJHuman View Post

I think the problem is that dynamic range figures are given with no validation whatsoever. No reference to any papers or other research on the topic. If they gave me a reference to something I could read, I would read it. But because I have yet to see any concrete data on dynamic range, I felt it would be best to do my own research to the best of my abilities.

In that sense, I don't see this as reinventing the wheel. There is no wheel, there's just a bunch of people asserting that they are aware of a wheel, but can't or won't show it to you

Based on your observations so far, the information published regarding PAR seems to be plausible, yes? Perhaps even understated with certain types of music?

No big power conspiracy?

Just because there is a knob doesn't mean you should turn it.
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post #750 of 2642 Old 04-19-2009, 12:46 PM - Thread Starter
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Originally Posted by whoaru99 View Post

Based on your observations so far, the information published regarding PAR seems to be plausible, yes? Perhaps even understated with certain types of music?

No big power conspiracy?

I never suggested a conspiracy. It's true that companies often mislead people. I was not trying to say I think Crown misleads people. I was making a general comment that it's in a company's best interest to present facts which are to their advantage. I understand how that could be misconstrued.

I think someone mentioned live vs canned music. And I totally believe live music has more dynamics having heard many bar bands and big stage acts over the years. Run of the mill bar setups, likely use little to no compression for example. So I don't doubt larger PAR numbers for those applications.

"But this one goes up to 11"
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