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Topic: watts |
Joe Delaronde
From:
Selkirk, Manitoba, Canada
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Posted 26 Nov 2004 9:05 pm |
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Watts (pun) the difference between 100 watts and 100 RMS in comparison to volume?
Thanks |
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John Daugherty
From:
Rolla, Missouri, USA
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Posted 27 Nov 2004 4:28 am
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Joe, which type of rating are you referring to when you say "watts"? Many manufacturers rate amps in "peak" watts, which for practical purposes is twice the rms watts.
If you are referring to 100 peak watts, this repesents 50 rms watts.
Doubling the power results in a 3db increase in sound pressure level. A 3db change is noticeable but in my opinion, not enough increase to write home about. Another difference you will notice when doubling the power, is the fact that you will have less distortion at half volume than at full volume. You may see this referred to as "headroom". |
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Roger Kelly
From:
Bristol,Tennessee
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Dave Boothroyd
From:
Staffordshire Moorlands
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Posted 27 Nov 2004 7:41 am
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RMS is just a mathematician's way of ignoring plus and minus signs.
With an audio device you are looking at a varying signal- whether it is the current or the voltage that varies, and sometimes the electricity flows one way, sometimes the other -that's A.C. So sometimes the voltage or current is a positive number, sometimes it is negative.
To measure the power in Watts, you multiply Volts by Amps- so the power varies as well. To judge the Wattage you can look at peak power or average power. RMS is a way of calculating average power without upsetting mathematicians.
Think of it as average power and you'll see why it is much more useful than peak power- which may only last for a tiny fraction of a second.
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Cheers!
Dave
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Joey Ace
From:
Hamilton, Ontario, Canada
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Posted 27 Nov 2004 7:59 am
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Comparing Watts to Volume is really not a good idea.
Volume is best measured in decibels.
Compare Watts to dB, and it starts to make more sense.
read this: http://forum.ecoustics.com/bbs/messages/34579/109138.html
That said, Watts can be specified in PEAK, AVERAGE, or RMS values.
The PEAK number is higher, so some amp makers specify the PEAK value, for marketing reasons. |
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Billy Murdoch
From:
Glasgow, Scotland, U.K.
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Posted 27 Nov 2004 9:18 am
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Joey,
Thanks for the great link.
I will have to read it several times to comprehend it but it certainly does put me right on understanding loudness.
Best regards
Billy |
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Dave Grafe
From:
Hudson River Valley NY
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Posted 27 Nov 2004 9:43 am
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If you are talking watts of amplification you must also have some knowledge of the "linearity" of the amp, i.e. at which point in its power curve does it begin to go into harmonic distortion and how much farther it can go before overtaxing its internal components. Unfortunately, most amp manufacturers only publish the numbers that they feel will sell more product.
You will see one amp listed at 200 watts @ 1% THD (total harmonic distortion), another at 250 watts @ 5% THD and yet another at 175 watts @ 0.015% distortion and when push comes to shove, the last one may well be capable of delivering the highest SPL (sound pressure level) and still sound clean while the second one will flat out blow your speakers first and the first one may burn up its power transformer just trying to keep up with the bass player.
Your little 15 watt Fender Deluxe may well be "louder" than any of them but it won't be a very clean tone. This may still be your best choice if it sounds right to you.
How's that for further confusing the issue?
------------------
 Dave Grafe - email: dg@pdxaudio.com
Production
Pickin', etc.
1978 ShoBud Pro I E9, 1960 Les Paul (SG) Deluxe, 1963 Precision Bass, 1954 Gibson LGO, 1897 Washburn Hawaiian Steel Conversion
[This message was edited by Dave Grafe on 27 November 2004 at 09:45 AM.] |
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John Daugherty
From:
Rolla, Missouri, USA
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Posted 27 Nov 2004 10:49 am
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After we have written all the technical jargon we can think of, the best way to find an amp to serve your purpose is..... get some reviews from people who have used them for that purpose. Or go to a store that stocks amps and try them. Keep in mind that the performance you get in the store will not be the same as it is when playing a gig.
I have a couple of amps that sound great at home but if I want to be sure that I can get a satisfactory sound in a new venue, I take my old reliable Nashville 400 and my Lexicon effects unit.....JD |
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chas smith R.I.P.
From:
Encino, CA, USA
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Posted 27 Nov 2004 2:10 pm
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| RMS is root mean square, the easiest way to think about it is, that it's the same number as (1/square root of 2) = .7071, so if you have 100 watts peak, then you have 70.71 watts RMS. |
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Earnest Bovine
From:
Los Angeles CA USA
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Posted 27 Nov 2004 4:01 pm
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| Actually, 100 watts peak means at the peak voltage. Power varies as the square of the voltage. So peak power varies as the square of peak voltgae. Thus peak power is twice rms power. |
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chas smith R.I.P.
From:
Encino, CA, USA
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Posted 28 Nov 2004 9:34 am
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| No, it isn't, it's one half of the chronosynplasticinfidibulum.... |
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Joe Delaronde
From:
Selkirk, Manitoba, Canada
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Posted 28 Nov 2004 4:40 pm
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Chas
Prove it.............. |
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chas smith R.I.P.
From:
Encino, CA, USA
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Posted 29 Nov 2004 9:11 am
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| Ok, ...now you see it......now you don't..... |
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