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#34553 - 16/07/2001 14:49 Music Power
schofiel
carpal tunnel

Registered: 25/06/1999
Posts: 2993
Loc: Wareham, Dorset, UK
Anyone recall what the truly awful marketspeak term "Music Power" refers to - is it RMS or Peak power?

One of the few remaining Mk1 owners... #00015
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One of the few remaining Mk1 owners... #00015

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#34554 - 16/07/2001 15:46 Re: Music Power [Re: schofiel]
tfabris
carpal tunnel

Registered: 20/12/1999
Posts: 31563
Loc: Seattle, WA
I've never heard that term used before. I have to say, though, that if it's marketspeak, it probably refers to the meaningless "peak" number.

I never purchase a piece of equipment unless I can see the RMS specs. That's one reason I buy from Crutchfield-- they always list the RMS numbers. It a lot of fun to see a photo of an amplifer in their catalog with a huge neon-lit "400 Watts" on top, and then see them rate it at 80Wx2.

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Tony Fabris
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#34555 - 16/07/2001 21:48 Re: Music Power [Re: tfabris]
msaeger
carpal tunnel

Registered: 23/09/2000
Posts: 3608
Loc: Minnetonka, MN
peak X .707 = RMS right ? just as long as they tell you if it's peak or RMS it doesn't matter which rating they use

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Matt

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#34556 - 16/07/2001 23:52 Re: Music Power [Re: schofiel]
mtempsch
pooh-bah

Registered: 02/06/2000
Posts: 1996
Loc: Gothenburg, Sweden
Most often it seems to be RMS x 2 x [suitable fudge factor (always > 1) to reach a nice, even and large number with no relevance to reality whatsoever...]

/Michael

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#34557 - 17/07/2001 03:27 Re: Music Power [Re: msaeger]
bonzi
pooh-bah

Registered: 13/09/1999
Posts: 2401
Loc: Croatia
peak X .707 = RMS right ? just as long as they tell you if it's peak or RMS it doesn't matter which rating they use

Right, as long as it is continuous peak, so to speak... Music power usually refers to peak power of short transients (when power supply draws power from its capacitors, and output stage relies on heath capacity of transistors themselves), if it refers to anything meaningfull at all...

Dragi "Bonzi" Raos
Zagreb, Croatia
Q#5196, MkII#80000376, 18GB green
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Dragi "Bonzi" Raos Q#5196 MkII #080000376, 18GB green MkIIa #040103247, 60GB blue

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#34558 - 17/07/2001 11:30 Re: Music Power [Re: msaeger]
tfabris
carpal tunnel

Registered: 20/12/1999
Posts: 31563
Loc: Seattle, WA
peak X .707 = RMS right ? just as long as they tell you if it's peak or RMS it doesn't matter which rating they use

Nope. If that's some kind of "standard" formula, I don't think any companies are following it. None of the peak-to-RMS ratios I've seen match it.

More often, the Peak number is a meaningless arbitrary number somewhere above double the RMS rating. The less reputable the company, the more spurious the number. Once, a long time ago, I bought a pair of really cheap speakers that were advertised as "200 watts". That was a peak number. No RMS rating was given. In reality, the speakers could probably handle about 5 watts (they were really cheesy).

Another trick I've seen is when a company reports the peak wattage at a 2-ohm load. I saw an amp in Crutchfield with a big "750w" painted on it. The "750" was based on peak at 2 ohms, but it was actually a 150x2 RMS amp at 4 ohms.

The RMS number is the only one you should pay attention to. And since companies seem to differ in how they report the Peak number, you can't determine an accurate RMS number from it.

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Tony Fabris
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#34559 - 19/07/2001 17:04 Re: Music Power [Re: tfabris]
Ezekiel
pooh-bah

Registered: 25/08/2000
Posts: 2413
Loc: NH USA
I believe the .707 number would be correct were you listening to a pure sine wave, if memory serves.

-Zeke

just say you weren't paying much attention...
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#34560 - 25/07/2001 22:19 Re: Music Power [Re: tfabris]
muzza
Pooh-Bah

Registered: 21/07/1999
Posts: 1765
Loc: Brisbane, Queensland, Australi...
The "750" was based on peak at 2 ohms, but it was actually a 150x2 RMS amp at 4 ohms

Even RMS by itself is a bit meaningless. You still need to know what distorsion is produced at that power and what frequency range they used. This may be covered in another thread but things like THD (Total Harmonic Distorsion) should be included in the rating.
Your 400W Max mega sound system may mean that the speackers actually started burning at 400W but stoped playing anything meaningful at 120W and had 50% distorsion at 50W. They were also playing a 100 Hz Sine wave through it at the time.

If you had a speaker rated as 120W RMS, 0.06%THD @ 180-19KHz, then you have a more meaningful description of the speaker / amp. Get this kind of reading on a 'el cheapo' speaker? I think not

Murray 06000047
I don't think, therefore I am not.
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#34561 - 25/07/2001 22:36 Re: Music Power [Re: schofiel]
muzza
Pooh-Bah

Registered: 21/07/1999
Posts: 1765
Loc: Brisbane, Queensland, Australi...
Anyone recall what the truly awful marketspeak term "Music Power" refers to - is it RMS or Peak power?

wouldn't 'music power' be some reference to the duty cycle of the equipment. ie. as music is more transient than sine waves, you can push the level more without raising the THD too much. Therefore the 'musicpower' is higher than the 'pure' RMS or maximum output.

Just guessing. any marketing gurus out there?

Murray 06000047
I don't think, therefore I am not.
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