Guitar Cabs

[thxgoon]

I wasn't sure where to post this but I think it still qualifies as home audio.?>

I was wondering if anyone here knew why they always seem to use multiple 12" drivers for electric guitar amps. I would imagine it has to do with sensitivity and high output but electric guitar has some pretty high frequencies in it that I would think would get distorted by the larger drivers. Is this distortion part of the design goals or are these 12" drivers special in their ability to reproduce a larger frequency band?

[Ricci]

Guitars need a lot of sensitivity to get the most out of a standard 100watt tube amp. Think about it... a half stack with a 100wt head can blow your head off and with a full stack, fuhgedahboutit. They also have to produce some fairly low notes at really high volume so the big cone area serves both purposes. The 12's that they use do have much more extended highs than your normal 10's or 12's, but it isn't superflat or clean. I don't remember off of the top of my head but I think that most guitar's top out at around 5500hz. I wouldn't call them excessively clean or high fidelity cabs, but if you are familiar with a lot of guitar players and their gear, this is not what is needed. Many cabs are voiced to have a certain sound.

[Wayne A. Pflughaupt]

thxgoon wrote:

I was wondering if anyone here knew why they always seem to use multiple 12" drivers for electric guitar amps.

As Ricci mentioned, any musical amplifier needs to get the most output for the watt, so they typically use highly efficient speakers (not “sensitive” – have no idea what that is).

However, that doesn’t address the proliferation of 12” speakers, IMO. The lowest fundamental on a guitar with standard tuning is ~80 Hz. So in reality, 10’s or even 8’s would suffice.

In my opinion, based on what I’ve seen working with guitar players, is that they like a big “full” sound, which translates to “more bass.” That’s the only good reason to use a big speaker for what should be a mid-to-upper-frequency instrument. While that makes the guitar sound great (at least to the guitar player), what it really accomplishes is muddying up the mix, because all the low end from the guitar(s) invades the bass guitar’s sonic domain. Adding insult to injury, a lot of the fuzz pedals seem to introduce a big boost in the 100-80 Hz region (possibly even lower – someday I’d like to check with a RTA).

(You don’t have to take my word for this; next time you go to a show where you can’t make out a single note from the bass player, pay attention to when a song opens with a guitar part – i.e. when it’s isolated from everything else on the stage. You’ll see that it has an exaggerated, throbbing low end. I’ll be fair and say it’s not always just the guitar player(s) at fault. Often it’s poor equalizing technique on the part of the sound engineer, as you’ll probably find everything else on stage from the vocals to the drums to the monitor mix also have excessive low end. It all combines to deliver a muddy mix.)

As for the sheer number of drivers – go figure. When I was mixing at a teen club a few years back I used to get a kick out of these guys rolling in these huge cabinets with four 12’s or even a pair of cabinets. I’m like, “Dude, I‘m going to stick my mic in front of one of those speakers and ask you to turn it down to about 3. What are all the rest of them doing for ya?” ’Course, I was too nice to actually say anything about it...

I would imagine it has to do with sensitivity and high output but electric guitar has some pretty high frequencies in it that I would think would get distorted by the larger drivers. Is this distortion part of the design goals or are these 12" drivers special in their ability to reproduce a larger frequency band?

I don’t know about the drivers being specially designed to better deliver the highs – I’ll take Ricci’s word for it. However, what a lot of players don’t realize is that, once they’re mic’d and coming through the PA, that “sound” that they work so hard for, that they bought that super-fine amp for – it’s gone. Most of the audience is not going to hear that “sound” or anything resembling it. The reason: PA speakers are a totally different design from guitar cabinets. This is why for my bass guitar rig I ditched the traditional amp/speaker combo years ago and put together something that worked with a PA system, to get me a better assurance that what I was hearing on stage had at least some resemblance to what the audience heard.

Regards,
Wayne