Amp wattage ratings...

[Hoodywah]

Soooo confused. I understand that big numbers move units but why is there not a more simplistic way to rate amplifiers and speakers? Why not use white noise or pink noise with standardized filters that emulate typical full frequency ranges of a specific source (such as guitar or bass)? It's just so ridiculously confusing. Sorry, I'm frustrated with it.

 

[nashvillebill]

Well, it's a complex subject, it'd be like simplifying nuclear fusion Well maybe not quite that bad!

But I think many folks approach the amp/speaker design backwards. They buy an amp thinking "how many watts do I need to keep up" when they really need to ask, "how much SPL do I need?" Then they should select a speaker cab based on the SPL and frequency response they need. Finally select an amp that will supply the power needed by that cab to meet the design SPL.

 

[Hoodywah]

But isn't speaker efficiency also measured with a couple or even a single frequency?
I have rather efficient speakers and get way too much volume if I crank it and I like that because it creates a safeguard for me and my amp cabinet combo. I typically play out with an Ampeg SVT-4 Pro and now have a custom built 412 that's loaded with Faital 12pr300 speakers; super efficient. So I can turn up and not worry about predictable mechanical failure

 

[nashvillebill]

Well, that's why you check the speaker's SPL for a given power rating over a whole frequency range. Eminence gives out good speaker specs, so does Faital I believe. Check out a free program called Win ISD. Give it the speaker you use, the box size, all the pertinent data, and it can tell you what the SPL will be. Not enough SPL--go to a different speaker.

 

[Hoodywah]

Or more speakers I guess. Haha.

 

[Mr. Foxen]

If people bought the right amp to start with, way less amps would sell, and that would not suit the industry.

 

[Vince Klortho]

I think those in marketeering will tell you that more descriptive specifications are counterproductive. Very few companies use them so they will have a tendency to make their product look worse than it actually is relative to their competitors. The problem is most people do not know what specifications mean or how to interpret the numbers ie., is lower better for this value or is higher better?

 

[Downunderwonder]

Consumers haven't made enough noise in the relevant official ears to get the law changed. I'm sure us bassists could come up with a useful standard signal and accepted distortion. Agedhorse disagrees.

 

[ThisBass]

Soooo confused. I understand that big numbers move units but why is there not a more simplistic way to rate amplifiers and speakers? Why not use white noise or pink noise with standardized filters that emulate typical full frequency ranges of a specific source (such as guitar or bass)? It's just so ridiculously confusing. Sorry, I'm frustrated with it.

That just reminds me on testing procedures to estimate power capability of loudspeakers.
Band width and peak limited noise which represents a random audio program.
In general the Peak to RMS ratio of the signal is set to +6dB.
On an amplifier this would mean the measured and rated output power is then probably halfed at least.
Amplifier output power measured with noise probably would lead to a decreased power rating, and therefore would lead to very dangerous pairings of amplifiers and cabs due to overpowered cabs.

Another problem is the missing of random dynamcs. The presence of dynamic transients is a very typical side effect to the majority of bass players. Some amplifiers may provide a burst capability that allows to handle typical dynamic transients whereas others don't provide any burst reserve.

Any capability of any amplifier to cope with short term transients can't be tested with a standardized steady noise, the way like it is done on loudspeakers.

Imo it would be best to provide two different power ratings,
one rating that represents the power for a steady sine wave 1%THD
and one additional rating for burst capapility (which then rates the power reserve for typical dynamics of a random bass player).

edit:
I'm pretty sure that guys like agedhorse may explain those things like above in a way more comprehensible expression and way more detailed than I can do.

 

[seamonkey]

The less you know, they more snake oil you'll buy.

Bass manufacturers appear to go by a code that you can sell so much snake oil, but if you try to sell too much at one time then you're going to get called out for it.

Then it's endless discussions about the snake oil and nothing about he science based engineering.

It's not hard for the average bass player to understand specs if they're based on a standard. There are no standards right now, so they are incomprehensible. No other industry would put up with it, even home theater is better represented. A side of a tire, or a box of cereal has more useful data than the average bass gear.

 

[Raf Seibert]

Another complexity that cannot be altered is that of human ears. We simply don't hear all frequencies the same. If we were to hear a sweep of frequencies as was posted recently, all at the same power, the middle frequencies will sound louder that either the high or the low tones. That's just the nature of our ears.

Howsomever, this doesn't need a law. We dont need another law for this. There's too many laws already.

Raf

 

[ThisBass]

It's not hard for the average bass player to understand specs if they're based on a standard.

Some standards are easy to understand but very often a standard does not tell what it means to the real world application.

May be that's the reason why so many folks claim a (easy to understand) continous power capability as the only real worlds true (rms) power?

The audible SPL of a given system is given by the average of the program material itself, rather then the big amount of power needed for the transients of the signal, and headroom isn't a thing that tells all the time how much louder you may blow up a system.
Probably that's a thing hardly understood by the average player, never the less it's very impressive to see how much amount of a signals transient envelope needs to be cranked till the ear will notice something like (unpleasent) clipping artefacts.

If trying to calculate a max SPL for a given system needs to know something about crest and dynamics of the program material. Jazz and classic audio programs demand for a very lot more of amp power at same SPL then compressed metal and rock programs.
The average would be the same but the transients are not.

 

[Vince Klortho]

Here's an example of what I mean, especially the last sentence :

We don't mention much specs in the manual for precisely the reasons SMASH mentioned: they can be misleading, and generally don't mean anything in regards to tone or volume. For instance, having a bass cab that can handle frequencies as low as 7 Hz isn't very helpful in the world of music - no one can hear that low, and having too much low end can muddy up a signal big time. It also doesn't show how fast the transient response of the cab is either - it may have great low end, but it's very slow and mushy. We prefer people to buy with their ears, not with their eyes.

 

[seamonkey]

Same old statement repeated thousands of times: "We prefer people to buy with their ears, not with their eyes."

If any manufacturer has measurements suck - the spew this line out. They must think their customers are brain dead.

I prefer to use my brain, my ears send data to my brain which my brain interprets as sound. My brain can also read measurements and steer clear of gear that isn't going to deliver. Ears are only part of it, not the total decision maker.

What's everybody doing here? Discussing and using our eyes to read.