#1
Watts (valve), Ohms and speaker ".

How do they all make a difference to the overall output volume and tone.

I have a 40w 1x12" @8ohms Fender blues Deluxe, how much more volume would another 1x12 8ohm speaker add to the overall volume and clean headroom (ie volume without breakup)

Also what is loader

A 65 fender twin reverb 85 watts into 4 ohms driving 2x12" 8 ohm speakers. (also why are there two ohm measurements; "into 4 ohms"???)

or a 65 super reverb 45 watts into 2 ohms driving 4x10 8 ohms speakers.
#2
Quote by NobleT
Watts (valve), Ohms and speaker ".

How do they all make a difference to the overall output volume and tone.

I have a 40w 1x12" @8ohms Fender blues Deluxe, how much more volume would another 1x12 8ohm speaker add to the overall volume and clean headroom (ie volume without breakup)

Also what is loader

A 65 fender twin reverb 85 watts into 4 ohms driving 2x12" 8 ohm speakers. (also why are there two ohm measurements; "into 4 ohms"???)

or a 65 super reverb 45 watts into 2 ohms driving 4x10 8 ohms speakers.

Adding a speaker does not add volume. It will sound more full, and possibly sound a bit louder, but in technical terms it does not increase volume.

You mean louder? The Twin Reverb is a good bit louder than the Super Reverb.

As for the mismatch on the Twin Reverb, its because the 2 8 ohm speakers are wired in parallel, making the overall cab ohmload 4 ohms.

Watts: Volume and headroom increase with wattage, though not in a linear fashion, and not uniformly between different amps.

Ohms: Ohms are really more to do with efficient operation of the amp than sound quality or volume. For simplicity sake, just remember to match ohms between heads and cabs and you don't need to worry about ohms beyond that.

Speakers: More speakers tend to sound more full, though the difference in volume is negligible. Speakers also have break up, like amps, so headroom can be negatively or positively effected by speaker choice.
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Last edited by tubetime86 at Aug 11, 2010,
#3
Here is a good explanation of how watts affect volume, and how speakers affect volume as well.

"The way that watts translate into decibels is in powers of 10. That being the case, if you want to do twice as loud, you need to go 10x higher in wattage. The difference in volume between 100W and 50W is actually only 12% less or so. HALF the volume of 100W is actually 10 watts, and TWICE the volume of 100w is actually 1,000 Watts."

Speaker efficiency is also key to volume. That curve is also not linear. If you take 2 otherwise identical speakers, one with a sensitivity rating of 103dB, and one with a rating of 100dB, that -3dB drop is the equivalent of sending half the power into the speakers... like moving from a 100W amp to a 50W amp, or about a 12% drop in volume.
Last edited by Matt420740 at Aug 11, 2010,
#4
Quote by tubetime86
Adding a speaker does not add volume. It will sound more full, and possibly sound a bit louder, but in technical terms it does not increase volume.

Why do you spout such bullshit? This is completely incorrect.

The difference between 1 and 2 speakers is double the effective surface area to dissipate the power over. I will spare you the technical details, but doubling the speaker surface area achieves the same volume gain as doubling the power (ideally - not totally achievable in practice though). It adds ~3 dB to your SPL at 1 m from the source.

Here is a graph I made for this forum only hours ago, which shows the ideal relationship between power and 1, 2 and 4 speakers of 98 dB efficiency...

Again, this is the ideal relationship, and doesn't accurate reflect what happens in real life - to do that i would need to know everything about everything do with the setup. But it is very close as a general reference.
Marshall amplifiers are the truest purveyors of rock and roll known to man.

"And give a man an amplifier and a synthesizer, and he doesn't become whoever, you know. He doesn't become us."

Holy crap, check this out!
#5
Nice graph... Increasing the surface area is correct, but it decreases the excursion of each speaker. I'm tired of this debate, we've already been through this. I said numberous times in that post that there is some percieved increase, but it is basically negligible. 3 dB is basically negligible. The JND for sound is 1 dB so 3 dB is noticeable, but just barely. Its certainly not a functional difference.

I don't think TS wanted a science lesson, I think he wanted to know how these factors affect him and his gear.
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Unless its electronic drums.

BURN THE WITCH!!!!!
#6
Quote by tubetime86
3 dB is basically negligible.

I disagree with you wholeheartedly on that. Get yourself a dB meter and sit in front of your amp. Start at some volume, and then turn it up by 3 dB and see what the difference in perceived volume is.

And thanks - it is a nice graph. Get yourself a copy of Matlab and you can do them yourself.
Marshall amplifiers are the truest purveyors of rock and roll known to man.

"And give a man an amplifier and a synthesizer, and he doesn't become whoever, you know. He doesn't become us."

Holy crap, check this out!
Last edited by seemeel at Aug 11, 2010,
#7
Quote by tubetime86
Nice graph... Increasing the surface area is correct, but it decreases the excursion of each speaker.



+1

Running a 25W amp into 1-12" speaker will put 25 watts into that speaker. If you add another speaker, you are decreasing the amount of power into each speaker. Doubling the speaker surface area IS NOT the same as doubling the power.

If you were wanting to increase volume, you'd be better off getting a speaker with a higher sensitivity rating instead of adding another speaker.
Last edited by Matt420740 at Aug 11, 2010,
#8
Quote by seemeel
I disagree with you wholeheartedly on that. Get yourself a dB meter and sit in front of your amp. Start at some volume, and then turn it up by 3 dB and see what the difference in perceived volume is.

And thanks - it is a nice graph. Get yourself a copy of Matlab and you can do them yourself.

I used to do car stereos... I'm perfectly aware of what a 3 dB increase sounds like, and its not going to change my opinion of what I'm buying or using, so its irrelevant to guitar gear. I have two cabs for my Valve Junior, a 4x12 and a 1x10, and there is no volume advantage whatsoever when using the 4x12 versus the 1x10.

I don't need to make graphs to understand things. Real world perceptions and laboratory data sets are collected differently, and the results are often different. In this case we are talking about real world perception, not lab data.
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Unless its electronic drums.

BURN THE WITCH!!!!!
#9
Arguing on the internet is extremely fun. I'm going to bed. Suffice it to say that neither of you have done your homework if that's your understanding of how multiple speakers work.
Marshall amplifiers are the truest purveyors of rock and roll known to man.

"And give a man an amplifier and a synthesizer, and he doesn't become whoever, you know. He doesn't become us."

Holy crap, check this out!
#10
Quote by seemeel
Arguing on the internet is extremely fun. I'm going to bed. Suffice it to say that neither of you have done your homework if that's your understanding of how multiple speakers work.


You're the one who came here looking for an argument, accusing someone of "sprouting bullshit"

Look bub, Just because you made a graph does not make your graph right. Get over yourself.

If you could increase volume so much just by adding speakers, then why do they make such high powered PA amps? Why not just take a 50w PA amp and keep adding speakers to it?

Using your logic, you could PA an entire stadium by adding 100 speakers to one 50w amp, since every time you double the speaker surface its like doubling the power. Do you see whats wrong with your idea yet?

If not, I think you're the one who needs to do some homework.
Last edited by Matt420740 at Aug 11, 2010,
#11
Quote by Matt420740
You're the one who came here looking for an argument, accusing someone of "sprouting bullshit"

Look bub, Just because you made a graph does not make your graph right. Get over yourself.

If you could increase volume so much just by adding speakers, then why do they make such high powered PA amps? Why not just take a 50w PA amp and keep adding speakers to it?

Using your logic, you could PA an entire stadium by adding 100 speakers to one 50w amp, since every time you double the speaker surface its like doubling the power. Do you see whats wrong with your idea yet?

If not, I think you're the one who needs to do some homework.

Well he's not saying it doubles when the speakers are doubled... I think we all know that is not true. He said its the same effect as doubling the power... Which I completely disagree with also. I've never heard anything to support that, but I've read plenty to challenge it.

Its really just a semantics argument. Is there a difference from one speaker to two? Yes. Is it a big enough difference that it should be taken into consideration when purchasing? No. Is this is a website for discussing scientific findings? No. Is this a website for reviewing gear and informing people on gear useage and purchasing? Yes. Problem solved!

Seemel, this isn't an argument. The only personal attacks have come from you, and I ignored them.
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Unless its electronic drums.

BURN THE WITCH!!!!!
Last edited by tubetime86 at Aug 11, 2010,
#12
Quote by tubetime86
Well he's not saying it doubles when the speakers are doubled... I think we all know that is not true. He said its the same effect as doubling the power...


Did I say he said it doubles?

he said "same effect as doubling the power"
I said " like doubling the power"

If it has the same effect as doubling the power, then it would be like doubling the power.

I don't see much difference there in what was said, I just worded it differently. Bottom line he is wrong.
Last edited by Matt420740 at Aug 11, 2010,
#13
Quote by Matt420740
Did I say he said it doubles?

he said "same effect as doubling the power"
I said " like doubling the power"

If it has the same effect as doubling the power, then it would be like doubling the power.

I don't see much difference there in what was said, I just worded it differently. Bottom line he is wrong.

No you're right... I was basically thinking 'there's no way he said that, its too blatantly incorrect and he obviously has a fair amount of knowledge...' But ya, you're right he did say that, and you're right that's just flat out wrong.

The other interesting question raised by the PA thing is at what point do you get diminishing returns? Surely somewhere around the 10th speaker running on a 50 watt amp you stop getting an increase in volume. At some point adding speakers will spread the power so thinly that you won't even get sound... So his whole argument makes no sense.

Edit: Seemel, please don't post on my profile just to say you disagree with me. I know you do, you made that clear here. Grow up.
Quote by Cathbard
Quote by Raijouta
Unless its electronic drums.

BURN THE WITCH!!!!!
Last edited by tubetime86 at Aug 11, 2010,
#14
Quote by tubetime86
.

The other interesting question raised by the PA thing is at what point do you get diminishing returns? Surely somewhere around the 10th speaker running on a 50 watt amp you stop getting an increase in volume. At some point adding speakers will spread the power so thinly that you won't even get sound... So his whole argument makes no sense.



Exactly my friend. Its why I brought the PA thing up.
Last edited by Matt420740 at Aug 11, 2010,
#15


I wonder if he'll come back to discuss further. If not I'm sure he'll just spam my profile some more to prove how he's above petty internet arguments.
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Quote by Raijouta
Unless its electronic drums.

BURN THE WITCH!!!!!