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Bass to Guitar wattage ratio?


pollock

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Is there any specific wattage ratio for balancing out guitar and bass or just do what works?

 

For example should the bass amp be 2x the size of the guitar amp?

 

Lets say:

 

65 watt guitar amp > around 100 for bass?

 

100 watt guitar amp > around 200-250 for bass?

 

2 120 watt guitar amps > 350 - 400 for bass?

 

Also, if a large enough bass amp is not available could a smaller one be mic'd and pushed up with PA volume?

 

Final question - i promise - if both a guitar amp and bass amp are mic'd, whats the best way to make sure the bass is heard?

 

Thanks in advance, guitar is my thing, I'm new to this stuff.

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Yeah... but wattage doesn't really mean very much in practical terms.

 

You can get small valve amps that completely drown out larger SS amps and then there's all the speaker stuff as well... Oh, the pickups too. And so on and so forth...

 

I think you just have to go for what works. |In my experience, there's no Pythagoras' Theorem type rule that really holds water. Mostly.

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Originally posted by Bluesape:

Bass doesn't need to be mic'ed in a small room.

Well, it doesn't hurt to have it in the mix if you keep the channel it's on eq'ed bright. That way you can get some definition for the bass' sound envelope, but use the amp's sound to fill out the low end.

 

Originally posted by Bluesape:

Roughly triple the wattage as required for guitar as bass notes are much thirstier in terms of wattage versus volume. :idea:

yeah, and to keep it clean if you make it loud, you need a lot of headroom, and wattage may not have a lot to do with percieved loudness, but it is a pretty good way to gauge how much headroom you have.

Always remember that you�re unique. Just like everyone else.

 

 

 

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Yeah, no real formula that is easy to explain... Speakers designed for low end are way less efficient (usually it takes two of them at the same wattage to keep up with one guitar speaker). And it takes more watts to reproduce below 125 Hz if you want the ear to hear it as equal, due to the ear's relative lack of sensitivity there, described by Fletcher-Munson equal loudness curves:

 

http://www.silcom.com/~aludwig/images/Fletcher-Munson.jpg

 

Of course only some of the bass guitar signal is below 125 Hz, but it does have an impact on how much wattage it takes.

 

Then there is masking - that's the phenomena of higher-pitched instruments' overtones masking the overtones of lower-pitched instruments.

 

And finally, many bassists want a cleaner tone especially if using a low B string, so not as many are using tubes and cascading gain, which adds a lot of overtone emphasis and can sound a lot louder than a dB meter would indicate.

 

I'd say 4 times the power for at least the same number of speakers is the minimum if you are talking just the backline and not PA support, and many bassists these days are using say 10 times the power, especially if they are using 5 or 6 string basses and cabs that are made to reproduce a lot more lows, whcih in turn are less efficient yet.

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Originally posted by greenboy:

Yeah, no real formula that is easy to explain... Speakers designed for low end are way less efficient (usually it takes two of them at the same wattage to keep up with one guitar speaker).

Yes, and that's assuming all the speakers (guit & bass) are of the same quality.

 

Anyway, I don't think you could really say something like "I have a 50W amp and that's necessarily going to be louder than a 45W amp" and expect to be right 100% of the time.

 

Originally posted by crazyguitarist11:

Final question - i promise - if both a guitar amp and bass amp are mic'd, whats the best way to make sure the bass is heard?

Well, the two amps need to be turned down as much as possible, in order to make sure that all you're getting out front is the PA. After which, it'd be no different to mixing anything else.

 

NB: bass amps are a bit unusual in that they "project" a lot. You can be standing next to a bass amp and not hear it very well, whereas someone in the audience, 10 feet away will be deperately yelling at you to turn down.

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Yes. True. Looking at hundreds of T-S specs for drivers will tell a lot of the story. But speakers designed for bass are almost guaranteed to be at least 3 dB less effient than counterparts for guitar when you sum it all up. That's the equivalent of a halving (or doubling) of wattage.

 

One reason for this is that generally, bass speakers have to be stiffer in suspension. And that's not even considered desirable for guitar, generally. Bass speakers have to act like a piston, have ability to do greater excursion without rubbing the voice coil against the gap.

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bass amps are a bit unusual in that they "project" a lot. You can be standing next to a bass amp and not hear it very well, whereas someone in the audience, 10 feet away will be deperately yelling at you to turn down.
Actually that's not true. They don't project any more than guitar speakers do. Both are privy to the laws of physics, in this case it's described by the inverse square law.

 

But what is happening here, is that the long waveforms of low frequencies interact with the room resonances more, and cause what is often called standing waves. And as those long waveforms bounce back off surfaces and mix in with the direct output of the speakers the waveforms are so long that in some locations they are arriving out of phase which makes that area have little or no content at that frequency, and where they arrive totally in phase, the output gets doubled. In any area in a room or on stage this could be different.

 

The problems low frequency reproduction faces are a lot different than what midrange and treble faces.

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Originally posted by greenboy:

But what is happening here, is that the long waveforms of low frequencies interact with the room resonances more, and cause what is often called standing waves...

Ok, so it's not the bass amp/speakers projecting in a different way to their guitar counterparts.

 

But the frequencies, etc, can sometimes confuse the "w(h)at(t) is the ratio" ;) topic even further, IMHO, because the sound you hear can vary in a different way to what you can hear from the guitar amp. Does that make any sense?

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Entirely. In some rooms I can practically be standing on my rig to hear what I want, in others I may be roaming partways across the stage to hear what wireless is showing me in the center of the dance floor.
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In a practical sense, I have had to purchase twice the wattage that of my guitar counterpart in order to get a blended sound without distorting my tone.

 

 

By the way, this is my first time visiting the Guitar Forum. Thank you "Ellwood" for the invite.

"Some people are like "slinkies". They're not really good for anything;

but they still bring a smile to your face when you push them down a

flight of stairs."

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There is no set ratio. To believe otherwise is foolish.

 

Every instance will be different, not only because of the blending of the two instruments' tones, but also the room acoustics. The same two instrument/amp setups will not balance the same, with identical settings, when placed in different acoustic environments.

 

Of course you can run bass through your PA, Crazy. (Can I call you Crazy? ;) ) Of course that assumes you have a PA capable of reproducing your bass adequately and you have either a monitor system or enough stage volume from the small amp to accomodate your needs onstage. For many bands that's asking a lot of their PA, whose primary function is to reproduce vocals and other acoustic instruments before keys, guitar, bass and drums.

 

I spent a month in the Mideast with a "No Doubt"-ish rock band, in support of the troops back in 2002. The bass player showed up at the airport with an Eden combo in an ATA flight case. All 163lbs. of it.

 

Now we had plenty of overweight items. 2000lbs. of PA, instrument amps, etc. But the airlines back then would carry 70lbs. per bag free of extra charges, then charge up to 100lbs. They refused to load anything heavier. A half hour before the flight left Nashville I was in the car with one of the musicians' dads, racing to Gibson Corporate headquarters for a small amp. They handed me a Trace Elliot Commando. A tiny practice amp. We threw it in the cavernous ATA case and I made the flight just in time. Thank goodness this wasn't in the past year, with increased TSA inspection backups.

 

That amp managed to provide enough onstage sound and I DI'd the bass into the PA the entire tour. Judging by the reactions the bass player received at army, navy, airforce, and marine bases I'd say the audiences could hear him fine, and he didn't complain once. :thu:

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Not to mention that in a band with downtuned guitars and using nothing but ultragain settings with scads of low end, the bassist rig is going to suffer a different stress than if playing with folkies whose upright player couldn't make the gig.
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It's pretty simple... guitars and bass are two different instruments, working in different frequency bands, and with two very different requirements.

 

Guitar? We want distortion.

 

Bass ? We NEED lots of clean headroom.

 

So... the guitarist can buy what makes his rig work best for him, at the volume level at which he wants to play.

 

The bass player -needs- piles of clean power and cannot have too much. He can always turn down, but nothing can save the sound of an underpowered distorting bass amp.

 

The two do NOT relate to each other in the way that you want them to relate, because the requirements are not the same.

 

Bill

"I believe that entertainment can aspire to be art, and can become art, but if you set out to make art you're an idiot."

 

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Show business: we're all here because we're not all there.

 

 

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Well, I don't remember the power of the Mesa tube amp I was borrowing, but up against a 100W Marshall full stack and 100W Mesa (?) full stack it could be hard to hear what was coming out of the 2x12 and 4x12 cabs. I seemed to have more headroom with a 350W solid state head driving a full stack (two 4x10s), or even better with a 4x10 and the 4x12. I was probably turned up a couple of numbers higher than the guitar rigs.

 

It really didn't matter, though, because all of that volume was more than enough to make the drummer complain. :evil: It seems the Crown and the JBLs had an even harder time competing, but in that band singing was more of an "option" anyway. :D

 

I agree with Bill; you can never have too much headroom on bass. Don't freak if you see someone pull out 1600W for a bass rig, especially if they like to put out the lower frequencies (as from a low B string, or lower). As greenboy said, those low frequencies will just soak all the power.

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