When is a Watt, not a Watt

[Nicko]

According to those highly regarded chaps over at the Great British Bass Lounge [size=5]"[color=#353D4D][font=nerisregular]Not all manufacturers Watts are 'equal' in terms of loudness but with Markbass amps you get maximum bang for your buck".[/font][/color][/size]
[color=#353D4D][font=nerisregular][size=5]Is this actually [/size][/font][/color][color=#353D4D][font=nerisregular][size=5]true? I mean if someone quotes RMS or peak it should be a direct comparison shoudn't it?[/size][/font][/color]

[JTUK]

Not really sure it matter as long as it has enough............

If you turn your amp up to half way on the dial..what does that equate to..?? who knows..
so as long as you still have decent sound on the amp to spare you'll be ok.

I'd be more interested in whether the amp delivered the sound I wanted to hear...
right the way thru the range but some amps sound ok..until a certain point and then
get quite harmonically distorted or ugly sounding.

Two of the best amps I've used quite recently that 'amp' up very well
have been the TF550-B and the DB750..but then they are top end amps. IMO.

[Skybone]

It depends on whether it's a PEAK watt or a NOMINAL watt. Peak watts are with the amp at absolute maximum (everything on full), where Nominal watts is the amp's output before the signal starts to distort.

[SubsonicSimpleton]

A watt is a watt is a watt, but there is no set in stone standard for measuring amp performance, so manufacturers often choose to measure the performance of the amp using say a 1Khz tone which doesn't realistically say anything about how much oomph it can deliver the lower octaves where it really matters.

[Grangur]

[quote name='SubsonicSimpleton' timestamp='1446212146' post='2897773']
A watt is a watt is a watt, but there is no set in stone standard for measuring amp performance, so manufacturers often choose to measure the performance of the amp using say a 1Khz tone which doesn't realistically say anything about how much oomph it can deliver the lower octaves where it really matters.
[/quote]
+1 A Watt is 1 volt delivered at a rate of 1 Amp. This has nothing to do with output volume. Using Watts as a gauge of volume is like taking the mpg of your car a a gauge of speed.

For my job I sell lighting. We always are discussing the output Lumens per Watt. Surely with a stack config we should be talking about decibels per Watt?

Edited October 30, 2015 by Grangur

[Nicko]

[quote name='JTUK' timestamp='1446211740' post='2897770']
Not really sure it matter as long as it has enough............

If you turn your amp up to half way on the dial..what does that equate to..?? who knows..
so as long as you still have decent sound on the amp to spare you'll be ok.

I'd be more interested in whether the amp delivered the sound I wanted to hear...
right the way thru the range but some amps sound ok..until a certain point and then
get quite harmonically distorted or ugly sounding.

Two of the best amps I've used quite recently that 'amp' up very well
have been the TF550-B and the DB750..but then they are top end amps. IMO.
[/quote]

I couldn't agree more. When coupled with the size of cab etc, its all irrelevant. It doesn't actually matter, but I'd guess most people would narrow the search down by setting a wattage and price range to begin with. It was just when I read it I though "really???"

[Nicko]

[quote name='Grangur' timestamp='1446212524' post='2897778']
+1 A Watt is 1 volt delivered at a rate of 1 Amp. This has nothing to do with output volume. Using Watts as a gauge of volume is like taking the mpg of your car a a gauge of speed.

For my job I sell lighting. We always are discussing the output Lumens per Watt. Surely with a stack config we should be talking about decibels per Watt?
[/quote]

I'm pretty sure there is some correlation between wattage and sound power level (measured in dB). Sound power level is related to the sound pressure level (also measured in dB) that that we perceive as volume. The technicalities of this are beyond my interest, let alone my technical competence.What I maybe meant to ask was

Do two bass amps claiming to be 200W with identical frequency response run through identical speakers have the same loudness? Or are the lounge people right.

[razze06]

[quote name='Grangur' timestamp='1446212524' post='2897778']
+1 A Watt is 1 volt delivered at a rate of 1 Amp. This has nothing to do with output volume. Using Watts as a gauge of volume is like taking the mpg of your car a a gauge of speed.

For my job I sell lighting. We always are discussing the output Lumens per Watt. Surely with a stack config we should be talking about decibels per Watt?
[/quote]

I wish people used this metric to describe their products. Got bless science and engineering

[chris_b]

Markbass are neither louder nor quieter than any other similarly rated make on sale in the UK. To single them out for "getting the maximum bang for your buck" is a bit of marketing, IMO.

I prefer a clean sound so my advice is to get an amp that will go a lot louder than you need and adjust the volume down. For me 500 watts is the "standard", and IME all 500 watt amps are in the same ball park. I have never had a 500 watt amp that has run out of steam. I also use an 800 watt amp, but that only gets used because it can run at 2 ohms, when I want to add more speaker cabs together.

The cabs are the things that turn amp power into loudness. That's where the ratings and measurements can differ and so will your sound.

[Nicko]

[quote name='razze06' timestamp='1446213412' post='2897792']
I wish people used this metric to describe their products. Got bless science and engineering
[/quote]

The last thing we need is manufacturers confusing us with decibel ratings.

[dincz]

The short answer - a watt is always a watt. The difference is in how long an amp can maintain its rated power output. Some are rated for continuous power (often wrongly called "RMS") while others can only keep it up for a few tens of milliseconds (burst power ratings).

[razze06]

[quote name='Nicko' timestamp='1446214288' post='2897801']
The last thing we need is manufacturers confusing us with decibel ratings.
[/quote]

Do you prefer to be confused by watt ratings?

[Nicko]

[quote name='razze06' timestamp='1446216981' post='2897834']
Do you prefer to be confused by watt ratings?
[/quote]

Sound is very complex, and dB levels are not really helpful.
There's sound power and sound pressure. The same sound source will have two different dB ratings, one SWL and one SPL. The sound pressure level varies with distance, while the power does not.
Then there's the problem of combining dB ratings. Two sources of 50dB is not 100 dB, its about 53dB. One source of 50dB and one of 100dB is still 100dB.
And there's the problem of us perceiving different frequency bands as louder.

[Bill Fitzmaurice]

[quote name='Nicko' timestamp='1446213371' post='2897790']
I'm pretty sure there is some correlation between wattage and sound power level (measured in dB).
[/quote]Only in so much that with a given speaker as more power is applied SPL goes up. But there is no simple x watts= x dB calculation.
[quote]The last thing we need is manufacturers confusing us with decibel ratings. [/quote]That's one of the reasons given by manufacturers as to why they don't produce measured SPL charts. It's a smokescreen for the real reasons, those being either they don't want you to see them, or they don't have them. Or both.

[Grangur]

Given that a driver will produce output across a wide range of frequencies I guess the only useful way you can produce a decibels per watt "figure" would be a response curve. Anything else would lead to strange, unhelpful claims, including if they included significant levels of output that, in reality, is outside the hearing range of an average human.

Which gets me thinking about the OP's point. Maybe both speakers give the same over-all sound volume, but maybe it's more a matter of how much amplification emphasis is spread accross the frequencies being processed (i.e. the EQing, even if they were all set "flat" different amps will respond differently.) Then there is also a small matter of how different frequences will bounce around the room differently. The trouble with the OP is he's only a human, and his hearing will also be only making an interpretation based on his own ears' reception of the frequencies after the sound has bounced about the room a bit. AND his ears will have different sensitivities to different frequencies too. So it's all unscientific.

[Phil Starr]

[quote name='Grangur' timestamp='1446212524' post='2897778']
+1 A Watt is 1 volt delivered at a rate of 1 Amp. This has nothing to do with output volume. Using Watts as a gauge of volume is like taking the mpg of your car a a gauge of speed.

For my job I sell lighting. We always are discussing the output Lumens per Watt. Surely with a stack config we should be talking about decibels per Watt?
[/quote][quote name='Grangur' timestamp='1446212524' post='2897778']
+1 A Watt is 1 volt delivered at a rate of 1 Amp. This has nothing to do with output volume. Using Watts as a gauge of volume is like taking the mpg of your car a a gauge of speed.

For my job I sell lighting. We always are discussing the output Lumens per Watt. Surely with a stack config we should be talking about decibels per Watt?
[/quote]
[quote name='razze06' timestamp='1446213412' post='2897792']
I wish people used this metric to describe their products. Got bless science and engineering
[/quote]
[quote name='Nicko' timestamp='1446214288' post='2897801']
The last thing we need is manufacturers confusing us with decibel ratings.
[/quote]

Rich is right, that's a good analogy. When lighting a room you don't really need to know the power, you need to know how much light it gives off. The electrician who wired the room might want to know the power so they can calculate what cables to use and the bill payer might want to know what the bills might be but the brightness is the thing you want to know, and then basically 'is it enough?'

And if you know how many decibels it produces at one metre you know how much it produces at two or even at the back of the room. It is slightly complicated by the frequencies, it's harder to see in just blue light or just red light and you may prefer warm white to cool white just as you may prefer to emphasize certain frequencies from your rig.

So if you want to see if a bulb is powerful enough look first at how many lumens to see if that 5w LED really is equivalent to a 60W incandescent and if you want to see if your stack is loud enough ask how many decibels it produces. It won't tell you much about the colour of the sound but it's the best single measure you can have of how loud it will go. That's why they don't often tell you that figure. Decibels every time before watts, though of course amps alone don't produce any decibels without a speaker on the end.

Edited October 30, 2015 by Phil Starr

[Twigman]

The wattage of the amp is irrelevant really. It's down to how efficient the speaker is in converting that electrical power into moving air.

[Phil Starr]

[quote name='Twigman' timestamp='1446247406' post='2898160']
The wattage of the amp is irrelevant really. It's down to how efficient the speaker is in converting that electrical power into moving air.
[/quote]

Sorry that just isn't right. It rouses the science teacher in me. How loud an amp and speaker are together is a very simple equation. Volume increase is a logarythmic scale so to keep it simple you add 3db every time you double the power (the watts)

For example if you have a speaker that produces 96db at 1Watt then it will produce 99dB at 2W, 102db @ 4W and so on.

For bigger increases in power an even easier figure to remember is that ten times the power gives you an extra 10db. and 100x the power 20db extra. So the same speaker will make 116db @100W

If you took a speaker that only turned 1W into 93db of sound then it would take 200W to make the same 116db and if you had an efficient speaker of 99db/W it would only take 50W to make 116dB. You need both the Watts and the efficiency to calculate the sound level. Neither is irrelevant. 120db will make you as loud as almost all drummers.

By the way the same law applies to drummers. If a drummer is twice as powerful you will get an extra 3db and an extra 6db if he or she is four times as powerful. you don't often get drummers eight times as strong as other drummers so this is the normal range of the loudest sound difference between them.

Edited October 31, 2015 by Phil Starr

[4-string-thing]

I find this quite fascinating, my old Acoustic 220 is only rated at 180w at 2 ohms and only 125 through my 4ohm 2x15 cab. Yet, it as "loud" as my (modern) 575w Ashdown head through the same cab. The cab, which is also a 40 year old Acoustic 402 has a label on the back warning that sound levels may exceed 120 decibels. 120 db from a 125w amp..... Maybe thats just marketing hype too? All I know is, that amp has always been loud enough to cope with most bands I've ever been in (except one who were just ridiculous when it came to levels) And that it got no louder after about 3 on the volume pot!

With regard to Phils comments about lumens per watt etc, when I worked for an electrical wholesaler selling LED lamps, people always thought cool white lamps were brighter than warm white, despite the same output. They may "look" brighter, in the same way that some amps may "sound" louder despite the wattages being the same?

[Grangur]

[quote name='Nicko' timestamp='1446211109' post='2897759']
According to those highly regarded chaps over at the Great British Bass Lounge [size=5]"[color=#353D4D][font=nerisregular]Not all manufacturers Watts are 'equal' in terms of loudness but with Markbass amps you get maximum bang for your buck".[/font][/color][/size]
[color=#353D4D][font=nerisregular][size=5]Is this actually [/size][/font][/color][color=#353D4D][font=nerisregular][size=5]true? I mean if someone quotes RMS or peak it should be a direct comparison shoudn't it?[/size][/font][/color]
[/quote]

Re-reading the OP's post a bit more meat on the bone would be interesting. When he refers to an "amp" does he mean amp-head; so he's comparing 2 heads that have been used into the same cab stack, giving different apparent volume levels. Or is he comparing one make of combo against another?

[discreet]

I always thought a Watts were like a miles-per-hour rating, i.e. how fast electrons are speeding down the motorway. Or something.

[Bill Fitzmaurice]

[quote name='4-string-thing' timestamp='1446291071' post='2898357']
120 db from a 125w amp..... Maybe thats just marketing hype too?
[/quote]If a cab has 100dB/1w sensitivity it only takes 100w to reach 120dB.
[quote]And that it got no louder after about 3 on the volume pot![/quote]Google 'gain structure'. The position of the knob has no relationship with the output. If you were to change the volume pot value and/or taper you would change at what knob position full gain is achieved.
[quote]I always thought a Watts were like a miles-per-hour rating, [/quote]They're the same as a horsepower rating. In that vein, which will go faster, a 200HP vehicle or an 800HP vehicle? That depends on issues totally unrelated to power. A 200HP BMW will go considerably faster than an 800HP tank.

Edited October 31, 2015 by Bill Fitzmaurice

[RandomBass]

[quote name='Bill Fitzmaurice' timestamp='1446293513' post='2898387']
A 200HP BMW will go considerably faster than an 800HP tank.
[/quote]
Indeed, which is why lighter cabs are louder than heavier ones. Oh...

[4-string-thing]

[quote name='Bill Fitzmaurice' timestamp='1446293513' post='2898387']
If a cab has 100dB/1w sensitivity it only takes 100w to reach 120dB.
Google 'gain structure'. The position of the knob has no relationship with the output. If you were to change the volume pot value and/or taper you would change at what knob position full gain is achieved.

[/quote]

This is why I find it fascinating, even though I don't really understand it.... If only it went up to 11.....

[Bill Fitzmaurice]

[quote name='4-string-thing' timestamp='1446301126' post='2898457']
This is why I find it fascinating, even though I don't really understand it.... If only it went up to 11.....
[/quote]The volume control acts like a water valve. One may configure a valve to be fully open with 1/4 turn, 1/2 turn. 3/4 turn or for that matter with ten turns.