Huh? There are so many false assumptions in this post I don't even know where I want to begin. Just suffice to say, no, this is not a way to estimate amplifier power, for more reasons than the moderators would care to let me consume bandwidth to explain.
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How to test an amps true power output
- Thread starter Ihaveshingles
- Start date
If you really feel the need to do this, use an SPL meter (set to C range for lows), one cab fully capable of going well beyond anything you'll put through it, one bass with the same settings and play the same note the same way; I'd use the C on the A string, that's mostly in the middle of where I play, I guess. Attach and crank each amp until you think it just starts to break up and STOP. Compare what the meter says and what your ear says. The loudest one might be the highest rated; then again, it may not. Hopefully you won't break anything because of curiosity.
Don't have an SPL meter? Yeah, most folks don't have one in their gig bag. You can pick one up online for thirty bucks that might work IF it's worth that much to you.
I only bought one 25 years ago, analog of course, because my son wanted to do a science fair project about sound. But I also used it to set up my 6.1 surround system speaker balances, so I got my money's worth. It's still around here somewhere, but it's been two decades since I've used it.
Or just go by your ears like folks have said.
Don't have an SPL meter? Yeah, most folks don't have one in their gig bag. You can pick one up online for thirty bucks that might work IF it's worth that much to you.
I only bought one 25 years ago, analog of course, because my son wanted to do a science fair project about sound. But I also used it to set up my 6.1 surround system speaker balances, so I got my money's worth. It's still around here somewhere, but it's been two decades since I've used it.
Or just go by your ears like folks have said.
Would you dispute this is the safest way? I'm more than willing to listen to anything that would pose a lessor risk than my method. My guess is that the only thing safer would be to stand 10 feet away from your amp with your guitar unplugged... calculate the capacitance between your guitar and amplifier and then do the math to figure out what the comparative output would be would you have been plugged in, with your amps output stages cranked. I'm sure the moderators would be as interested in your answer as I am.
I hope others understand that for me to be condescending I'd have to have a significantly overvalued opinion of myself. Probably not going to happen. I've grown into the skin of a realist.
Well, it is possible the amp doesn't meet it's advertised power specs, but it is probably very close in perceived loudness terms.
But those electrical watts have to go into a speaker to make sound. If the speaker is especially efficient you'll get more sound out of less electrical watts. Maybe. Or maybe you'll get really loud midrange with weak lows.
I choose to not fret over it. To me, amps are in power classes; 300-ish, 500-ish, 1000-ish. Whether my 350 watt amp actually hits 350 watts doesn't matter. It is in the 300-ish category.
But those electrical watts have to go into a speaker to make sound. If the speaker is especially efficient you'll get more sound out of less electrical watts. Maybe. Or maybe you'll get really loud midrange with weak lows.
I choose to not fret over it. To me, amps are in power classes; 300-ish, 500-ish, 1000-ish. Whether my 350 watt amp actually hits 350 watts doesn't matter. It is in the 300-ish category.
The most sensitive way to measure loudness is with the human ear. And since loudness varies with power, an indirect measure of power would be to listen.
The standard for speaker sensitivity (essentially loudness) is measured in dB/Wm at 1kHz - so dB as measured at 1 meter at 1 watt with a signal at 1kHz. So for a home set up, use your bass to play C6 (1046.5 Hz) and listen with your head at 1 m (about 3 ft) at full volume.*
* I am not a hearing professional, but you may want to consult one after this experiment. Also, all advice given is purely for my own amusement.
C6 on a bass? Not gonna happen. Maybe as a really weak harmonic on a high C string (C3). Definitely for your own amusement.
And, if it sounds too good to be true, ( the specs ), it probably is.
I'd say, check out the several, bass orientated, bass gear publications, they have done some in-depth reviews, with good test equipment & some summations that would answers your questions, what you'll notice, some of the test procedures my be debatable, but all in all, for the cost of a magazine, you won't have to buy test equipment, go through the learning curve.
Well.....if I did that, it would blow everyone out of the room. I use an 800-watt Eden amp (WT500/800) and I run it bridged at 800-watts into either my DNS-210 cab for indoors, or my DNS-410 cab for outdoor festivals. The highest I ever turn the master up with either of those cabs is 10 o'clock. I turned it up to 10:30 on my DNS-410 at a couple of outdoor festivals and immediately got told to turn it down. Never turned it above 10 o'clock on my DNS-210. Both cabs would handle the power of turning it up half-way (12 o'clock), but you couldn't stand to be anywhere near those cabs at those levels.
You have to remember, that SPL measurement (how loud it is) is a mix of both the amp's power and the cab's sensitivity. I'd be amazed if you could turn it half way up with Mesa amps and cabs either.
An amp's power rating is a number that's easy to understand but a concept that's harder to understand. Given a number, you can argue about it, as we are wont to do around here, but you are unlikely to even hear a difference in volume until you approach either half or double the power output. If you want twice as loud you need 10 times the power! Assuming you had the proper equipment and procedures in hand, measuring a [nominal] 200 watt amp and finding it's actually putting out 50 watts more or 50 watts less means nothing in practical terms. Nearly none of us would be able to hear the difference.
Nailing down an exact number through measurement doesn't give you anything useful.
- Feb 12, 2006
- 61,080
- 5
- 221,187
- Disclosures
- Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
Learn how to use the tools properly to measure loudness accurately.
Published specs, as @agedhorse points out, are all over the place, as no governmental or even a consumer organization requirement puts all pieces through exactly the same test, which would then give the rest of us unwashed mob a reliable yardstick with which to compare. I also agree you'd have to be a considerably accomplished engineer or tech that's fluent in several fields to duplicate what the manufacturers did (or didn't) do in testing their equipment to generate whatever specs they're willing to publish.
So unfortunately it's down to buying stuff you trust, and then the two real-world tests:
1. Sounds Good______ Sounds Bad_______
2. Not Loud Enough______ Loud Enough________ Geez Louise, that's REALLY loud __________
OK, now WHEN do I turn the STANDBY switch off ?
So unfortunately it's down to buying stuff you trust, and then the two real-world tests:
1. Sounds Good______ Sounds Bad_______
2. Not Loud Enough______ Loud Enough________ Geez Louise, that's REALLY loud __________
OK, now WHEN do I turn the STANDBY switch off ?
- Feb 12, 2006
- 61,080
- 5
- 221,187
- Disclosures
- Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
Still need some knowledge... or you can simply buy a vowel 
