Different Speakers Sizes

[Ewizard]

I have been doing sound for bands and corporate events for over 20 years now and can tell you in one word why it will never pay off to have smaller speakers in greater numbers for guitar cabs. ready for it? PHYSICS.

That's it. We still have to mic your cabinet in order to capture it. This means putting at least one microphone on it. When the source of the sound starts getting nearer the size of the capturing device things start getting weird. Making a small movement of the microphone results in either little or no change and or drastic change. This is because the source is that much closer in size to what is capturing the sound. So as you move the mic it doesn't change much because you already have a majority of the source captured in the microphone's diaphragm, or the change is hugely drastic because a small changer in direction captures the other sources nearby.

Another not-good thing is phase issues. As you introduce more and more sources to reproduce sound, it causes comb filtering. This is part of what makes 4x12" speaker cabs somewhat beamy. The spacing between the drivers and their size contributes to an off-axis sound profile that is less than ideal. This is why you have to have a small amount of distance between you and the guitar cab to really hear what it sounds like. Then when you get out into the crowd it sounds like a laser beam. Move 5' one way or the other and you can't really hear it the same way as when you are directly on-axis. Now imagine a microphone that is stuffed next to two sources that are spaced relatively close to each other. If the microphone hears more than one source at the same time, you will get comb filtering. The closer the sources are to each other the more this becomes a likely scenario. This is why having a smaller speaker, placed closer together is not always a great idea.

Now trying to use a crossover network isn't going to work either. Having a 12" speaker for lows and a 6" speaker for highs has to be captured at the same time. With a single microphone, how do you do that? Even with two mics, they still have to combine electrically in the PA somewhere. We are going back to phase issues again here. The physics of that idea just doesn't work well. Even splitting the mic between the two is not a good solution. When the mic is not equidistant or nearly on-axis of the sources, things get weird.

So what about bass guitars, they have multiple 8" speakers for some of their cabs, why does it work for them? Again physics. The frequency range that the bass produces is long enough that the spacing of the speakers do fairly well with it. I.E. the speaker's centers are close enough together that the wavelength they reproduce is not affected by phase as much; at least at the frequencies of interest. The higher frequencies suffer and this is why many bass cabinets use tweeters and a crossover to help things out.

Why is it that smaller speakers spaced close together do OK with bass frequencies? When two acoustic centers that reproduce the same wavelength ( sound ) are within 1/4 of a wavelength, they effectively couple. Once the distance between two adjacent drivers' acoustical centers goes beyond 1/4th of a wavelength they start to destructively interfere ( comb filtering ). A 100hz frequency sine wave has a peak to peak wavelength of about 10' ( technically 11' but close enough to 10' to use for rough guesstimation ). So the two acoustic centers ( speakers ) must be within 2.5' of each other in order to effectively couple. Most large bass cabs have 8" speakers that are placed pretty much right next to each other, so they will couple very well at 100hz, possibly even 200hz and below. Above that, they start to have comb filtering that helps or not with the sound of the cabinet.

So to recap, smaller speakers in larger numbers or even in standard quantities will actually make the common issues with guitar cabs worse aside from the weight savings. The best source for anything is a single source. The downside is that a single source now has to sound the way you want it to and cover where you want it to, in the weight you desire, and handle the power you give it. That is a lot to ask of a standard guitar speaker rated at 25 - 100 watts. Most guitar cabinets are not designed for acoustic reproduction perfection, they are designed to fit the head you put on it, to reduce the waste created from a 4'x8' sheet of plywood, and to be the standard shape of a box. Thiele small parameters, well-engineered box design, and outright acoustic perfection are of little concern for most guitar cab builders. To create a guitar cab that was designed as best it could be for a particular speaker would be very expensive to produce, would not be light, and probably wouldn't sound like you expect it to.

[ehdwuld]

my recent custom cab from TRM, was made with a 15 inch speaker cutout and I had Tim make me an adapter ring for a 12 until I get a 15

a buddy of mine ran his Twin through two 15 inch Scorpions (his bass Rig)
and it sounded HUGE

all the bright Twin/Eminence Legend sound was gone
thick with bass and Mid-range galore

[NegativeEase]

I like a mix of 10s and 12s.. most 15s are too slow for fast guitar playing in my opinion and using only 10s or smaller can even be too punchy and lack depth sometimes.

[Rex_Rocker]

I don't like 10"s, peronsally. They usually put them in compact cabs which tend to sound boxy by themselves. 10"s add to the boxiness, IMO.

Unless you're going for the Bassman open back sound, which I'm not, I find 10"s practically unusable with gain.

[Karloff]

Sounds like a sore back to me

lol, it sure would be ...

[jeremy]

ha! indeed it does. i have a 2x10 cab and a 2x12 cab. thats plenty for me. i have a 5e7 circuit amp with 1x10/1x12 and the mix of the two speakers is great

[playas]

I sometimes wonder what a cab with a 15", 12" & two 10"'s would sound like.

Sounds like a sore back to me

[JamesPaul]

I used to run my Classic 50 410 on my 115E cabinet. The 10"s really have some pop and the 15" I could feel in my core.

[Karloff]

guitar players are definitely slow to accept new things. all my amps have either 10" or 12" speakers and i like the sounds i get with them. i also dont use 7/8 string guitars or go for a modern sound.

you're exactly right. we want the latest & greatest, as long as it's exactly like it was 50 years ago. lol
I use 12's or 10's.
I sometimes wonder what a cab with a 15", 12" & two 10"'s would sound like.

[Demanic]

A speaker array with wider response has a really different sound from a regular guitar speaker.
FRFS speakers are great for modelers, or a preamp plus speaker simulation.
But with a classic amp they'll take you head off with the treble.

A few players have made it work but its not your typical rock sound.

And it is'nt just a matter of sound, it's the feel as well.
Smaller speakers have faster attack but they also have a tighter feel.
For most rock guitarists that's not ideal.



Lemmy's bass stacks each used a 2x15 on the bottom and a 4x12 on top. That's a badass rig.

I kinda like 15"s for guitar. A blackface Super Reverb loaded with an Altec 15 was downright amazing,
And I've made a Marshall 4x10 sound pretty darn great too, though it was quite tight in terms of feel.

Still, for me 12" speakers give the sound I hear in my head, with the feel I want.
Am simply using two now instead of eight.

I used to play my Shecter 7 string through my Carvin XV212 open back combo with a Gause 15" in a closed ported cab. Massive.

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[Chistopher]

Because it doesn't work, that's why you never, or rarely, ever see it.
If it worked, you'd have seen it gain popularity LONG ago.

You hang around messing with engineering or business long enough you'll find this is rarely the case.


I could see this idea being very useful in a FRFR speaker cab. With nothing but a 2" compression driver handling everything above ~1kHz crossing over to a 15" woofer handling everything below that. If you're a modeling amp company this would be golden. It would be highly efficient from an electrical standpoint, it would be cheaper to produce once you get past the overhead design cost, and it would be a neutral system that would be extremely easy to integrate with your company's other modeling systems.

With a bit of software you could have the cab model any set of speakers/configuration

[eclecticsynergy]

A speaker array with wider response has a really different sound from a regular guitar speaker.
FRFS speakers are great for modelers, or a preamp plus speaker simulation.
But with a classic amp they'll take you head off with the treble.

A few players have made it work but its not your typical rock sound.

And it is'nt just a matter of sound, it's the feel as well.
Smaller speakers have faster attack but they also have a tighter feel.
For most rock guitarists that's not ideal.

I've run an old Randall RG120-ES with a 4x12 and a 2x15 and it sounded fantastic.

Lemmy's bass stacks each used a 2x15 on the bottom and a 4x12 on top. That's a badass rig.

I kinda like 15"s for guitar. A blackface Super Reverb loaded with an Altec 15 was downright amazing,
And I've made a Marshall 4x10 sound pretty darn great too, though it was quite tight in terms of feel.

Still, for me 12" speakers give the sound I hear in my head, with the feel I want.
Am simply using two now instead of eight.

[Demanic]

I've run an old Randall RG120-ES with a 4x12 and a 2x15 and it sounded fantastic.

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[idsnowdog]

I have seen a few mini-cabs with 4x6 speakers. It's supposed to approximate the sound of a 4x12 with a smaller footprint for lunchbox amps. Seismic and Crate make them.

[Demanic]

Didn't Dime used to use a full stack that was a 4x12 on top of a 1x15? Or was it two cabs each with 2 12's and a 15?

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