Watts and volume

[billfitzmaurice]

You will get more volume by adding another 2x10 cab (or a 4x10 cab, 1x15, etc.) than upgrading the amp to say 500 or 750 watts and sticking with one 2x10. Is this correct?

Yes. Adding speakers increases the operating efficiency of the system.

 

[Bassman62]

I have read that the best way to add volume to a rig is to add speakers. For example you have 300 watt head and a 2x10 cab. You will get more volume by adding another 2x10 cab (or a 4x10 cab, 1x15, etc.) than upgrading the amp to say 500 or 750 watts and sticking with one 2x10. Is this correct?

Volume and loudness are two different things.
A 4x12 100 watt cab with a 100 watt amp sounds more pleasing than a single 12" 100 watt speaker driven by the same amp.

 

[Bassman62]

Not neccesarily related. Could have been AC supply differences, some slight change of monitors or mics position, even humidity or amount of people in room

This was a problem that many people encountered with PA systems in the 70s and before but not nearly as much today with better materials and larger voice coils.
Most of the UK PA manufacturers used the least expensive speakers available, Carlsboro etc were only paying £9 GBP $19 USD for a 12" speaker with a 1" voice coil.

 

[King David]

I am not intending to start a big theoretical question. If you could assume all things equal given 100w or 200w...500 w and 1000 w it appears that the consensus is it would not double the loudness. That is pretty much what I wanted to know.

So from what the consensus says all thing being equal (yeah right I Know) to have twice the loudness of a 100 w amp, I would need about 400 w.

 

[phillipmorephil]

I have read that the best way to add volume to a rig is to add speakers. For example you have 300 watt head and a 2x10 cab. You will get more volume by adding another 2x10 cab (or a 4x10 cab, 1x15, etc.) than upgrading the amp to say 500 or 750 watts and sticking with one 2x10. Is this correct?

I don't know if it's the -best- way, but it sure works. The more speakers you've got, the more air you move, the more sound waves are generated, or something like that.

 

[MascisMan]

I don't know if it's the -best- way, but it sure works. The more speakers you've got, the more air you move, the more sound waves are generated, or something like that.

Right thats what I was thinking. Wattage staying the same, adding more speakers, the louder you get.

 

[greenboy]

I am not intending to start a big theoretical question. {...} So from what the consensus says all thing being equal (yeah right I Know) to have twice the loudness of a 100 w amp, I would need about 400 w.

Maybe you should pay more attention to the "big theroretical answers" - because your question has roughly been answered several times.

 

[Bassman62]

Maybe you should pay more attention to the "big theroretical answers" - because your question has roughly been answered several times.

Not everyone understands the "big theroretical answers"; in many cases they are more than is required, in most cases laymen are asking questions so it would be nice to answer in more layman friendly terms.
I go along with "no it will not benefit you going from 100 to 200 watts enough to justify the cost involved" go for something with considerably more watts.

 

[tolson36]

I've read the Yamaha book and heard the science but I can tell the difference between 500 and 750 watts and even smaller differences.

"make increases by a factor of at least four to be worthwhile."

I don't agree although you may have the science on your side the point at which I feel comfortable with the headroom on a bass amp is what "drives me".

With my current cabs, my sweetspot on a power amp is 900-1,200 watts--and that's where I feel I can be heard in any situation with adequate headroom with freedom to EQ as much as I want and still have said headroom.

So the difference between 600 and 900 watts is significant because is represents the break between the clean and unclean power for my style, cabs, and EQ preference. I just think that once you get above a threshold, the issue changes. Plenty of loudness to gig is not the same as headroom.

If you use a 700 watt amp--but clip more than you like--but not a lot more--a change to 900 watts is significant in my opinion because it might bring you just above the minimum you need. What's wrong with that? And to tell someone that the difference is insignificant misses the point.


.......on tube amps, the difference between 300 and 200 watts seems a lot more than the science would indicate. The 300watt tube amp feels to me at least 50% louder than 200watt and very significant and certainly worth the upgrade if affordable.

 

[greenboy]

Not everyone understands the "big theroretical answers"; in many cases they are more than is required, in most cases laymen are asking questions so it would be nice to answer in more layman friendly terms.

The first of several in this thread that spell it right out: http://www.talkbass.com/forum/showpost.php?p=4145555&postcount=5

"100W x 10 = 1000W (double the volume)"

Then http://www.talkbass.com/forum/showpost.php?p=4145717&postcount=8

"10dB is twice as loud"

From http://www.talkbass.com/forum/showpost.php?p=4146578&postcount=12

"A 10 dB boost is a 10× power boost. A 10 dB boost in sound pressure level (SPL) is an approximate doubling of apparent loudness, on average across the audio spectrum."


Whose fault is it that other questions have ALSO been asked in this thread (nobody's, really), or that people who know what they are talking about also expound a little deeper on something that is not quite black-and-white (and why should they NOT want to go into greater depth?) - and then too, others introduce stuff that sometimes needs to be rectified.

If people want simple answers they are there and easy to see, but this forum is not only for the dumbed down versions, no?

 

[greenboy]

I've read the Yamaha book and heard the science but I can tell the difference between 500 and 750 watts and even smaller differences.

All with CLEAN power too I hope, and with equal voicing. Because otherwise the comparison would be melons and cumquats ; }

Anyway, that's over 1.5 dB so that's no great surprise. At moderate levels I can sometimes hear a 0.5 dB change in broadband material and always 1.0 dB. But it's hardly worth upgrading a rig's power amp for, which brings us to your next bit:

"make increases by a factor of at least four to be worthwhile."

I didn't write that, but you appear to be arguing something entirely different here... or you think that buying a new amp for only a small gain in clean power that translates into a dB or two is worthwhile. Might as well get a few more dB than that by my reckoning. Fourfold would be 6dB, but I'd sometimes find a 3dB increase worthwhile - TWICE the power. Just depends on where you are at and where you want to be and what's the cost...

So the difference between 600 and 900 watts is significant because is represents the break between the clean and unclean power for my style, cabs, and EQ preference. I just think that once you get above a threshold, the issue changes. Plenty of loudness to gig is not the same as headroom.

Are we jumping tracks here? Nobody was talking about distorted power stages previously when questions were being asked about dB and such. Sure - this is something to consider - but it certainly doesn't make the discussion that has gone on before in any way flawed.

If you use a 700 watt amp--but clip more than you like--but not a lot more--a change to 900 watts is significant in my opinion because it might bring you just above the minimum you need. What's wrong with that? And to tell someone that the difference is insignificant misses the point.

Your example is perhaps not so well constructed because that is just a smidgeon over a 1 dB gain - IF no speaker power compression is allowed for, if you haven't already exceeede xmax, etc. And if you are clipping past 700, going to 900 hasn't even bought you that 1 dB and you can almost hardly call THAT headroom. When it's that borderline you haven't really made sure you escaped the problem.

But the point itself is of course valid, though I'd be thinking more in terms of gaining THREE dB of true headroom.

.......on tube amps, the difference between 300 and 200 watts seems a lot more than the science would indicate. The 300watt tube amp feels to me at least 50% louder than 200watt and very significant and certainly worth the upgrade if affordable.

Uh, what science are you talking about here? There's plenty of additional understanding about the whys and wherefores for this phenom. It's mainly distortion causing harmonic emphasis, power stage compression, preamps/amps with differing gain structures, transformers.

Why do so many people want to take an incomplete understanding of their own and make it science's fault? Isn't it science that made this stuff available in the first place? There's a lot more science to these topics yet, and I'm sure more will continue to be discovered. But not by poo-pooing or ignoring current understandings.

 

[T-Bird]

Hi.

Extremely well said Greenboy.

I'd like to add one thing though.

Almost everybody seems to be referring to and using scientifical terms and in the next phrase or post complaining that answers using similar scientific terms flies over their head, so to speak.

To my somewhat restricted knowledge, there isn't any other way to explain those phenomenon, nor there will be. I do have a degree in (mechanical) engineering, so I should know

Correct me if I'm wrong, but isn't the possibility to gather information beyond Your education one of the wonders of the modern electronic (=internet) society. The information is there, You just have to filter it. And here we have pros to do it for You, or at least give You a push to the right direction. So what's the problem with that. Tell me please.

Could the next can of worms be speaker sensitivity, please.

Regards
Sam

 

[Bassman62]

I said layman terms which is totaly opposite to the inferance of dumb that many would find rather offensive, it would also be very easy to form the opinion that some people just like to show off their in depth knowledge on a particular subject without considering the reason that the question has been asked.

 

[T-Bird]

Hi, again.

In fact I'd like to add another thing too. A question or a two.

Some of You will be annoyed or pissed, sorry 'bout that.


How on earth do You guys know what the output power (wattage) of Your amp is to a given variable or fixed load? Or how it differs from the power that the particular amp can drive a speaker enclosure with, to be converted to a different form of energy to be heard and felt?

1.Do You rely on the marketing watts usually 1kHz and 0,1-1% THD? IMO mostly BS just alone.

2.Or do You measure Your amps, lets say on every 1 , 1/3 octaves or whatever, (even just one fixed freq), with a choosen THD and draw a chart, preferably with different THD values as well, to a known SPEAKER + cab load or an real speaker emulator, not with a fixed dummy? With sinus as well as program.

And then You determine what gets to its knees in every single band, is it the PSU, circuitry design, transistors/tubes, output transformer, and then do the comparison.

I'd guess the former?

Sorry again, if someone feels offended.

Regards
Sam

 

[King David]

Hey greeboy take a chill pill brother! If you would pay attention to my post you would see that I understood the answers, which means I did pay attention. My second post did not have any questions in it. They were all statements.
You all start talking about volume vs. loudness and percieved volume and stuff like that. If you really want to start a debate on the difference of loudness and volume feel free to do that, but it is not what I wanted.
The average person does not know what sensitivity is all about. I understand the basics, and I am fine to learn more and I have learned more.
Someone at the beginning mentioned that this was a can of worms being opened. That is what I meant when I said, "I am not intending to start a big theoretical question."

 

[Bryan316]

The only true way that I've found to test an amp's loudness, is a SPL meter in front of whatever rig, play it on each string, and find its max SPL at whatever string/frequency. Then move to the next rig.

There are so many variables, as everyone has shown, to give a concrete answer for every possible situation. Just playing style has such a tremendous effect on an amp's "loudness".

But as much as I wanna say just crank two rigs next to each other and see which is louder, I found LOTS of good information and explanations in this thread so far. Particularly the understanding that the human ear's frequency response is NOT flat, and our ear hears lows less strongly than mids. Which is why I bitch out so many guitarists who have guitar tone that's genuinely harsh on the ears when they crank it. Mostly cuz they set their rigs to sound good at low volume, instead of setting them to sound good at FULL BAND volume! Bedroom tone is not the same as stage tone.

Keep the thread going, guys... I'm learning tons from this.

 

[stedtale]

I think it really depends on what wood your bass is, what bridge you have installed and which cables you are using.

 

[Bob Lee (QSC)]

Bedroom tone is not the same as stage tone.

+1,000

 

[greenboy]

So from what the consensus says all thing being equal (yeah right I Know) to have twice the loudness of a 100 w amp, I would need about 400 w.

If that isn't a question posed in another form, it certainly is a WRONG conclusion. So those quotes should rectify that.

 

[greenboy]

I said layman terms which is totaly opposite to the inferance of dumb that many would find rather offensive, it would also be very easy to form the opinion that some people just like to show off their in depth knowledge on a particular subject without considering the reason that the question has been asked.

If threads were ONLY for the persons asking the most basic questions, why would anybody else participate beyond a certain point? Obviously, it's because the forums serve several needs beyond Audio or Bass 101 - you know, some of us like the 203 course an awful lot too. We can't maintain interest without discussing or debating what is a very complex and fascinating subject and it doesn't make sense to us to try to press everything down to a black-and-white when its patently obvious to us at least that it's a HUGE universe. Please bear with our attempts to take it further. Either that, or maybe there should be threads where no actual discussion takes place.

Sheesh!!!