Speaker matching and cabinets?

[devnulljp]

Quick question about speaker matching and cabinets:
I've only ever had identical speakers in multi-speaker cabinets...
So, does power rating of two (or more) speakers in the same cabinet have to be matched? I've heardof people mixing different speakers in 2x12 and 4x12s to get different types of sound but does it matter if you mix say one speaker rated at 150 W with another rated at 50W? How does that affect the amp? I'm guessing you would want the amp rating to be no more than double what the lowest power speaker can handle...? So, is the only thing that's really important to match the ohm rating?

Also, related -- I see used cabinets with or without speakers go all the time for anything from $200 up to thousands and new cabinets without speakers seem to go in the same range. (YellowCab has some very pretty cabs but they're $1100 each for a 2x12, and I think that's w/o speakers). Is there really such a huge difference in the box used to hold the speaker? I guess real wood or plywood would be preferable to some of the more chipboard-like ones but really anything else?

[Hamm Guitars]

I think mixing speakers is just a bad idea if you play live. Unless you are a big rock star there is a 95% chance that you are only getting one mic on your guitar cabinet so I don't see the point in mis-matching speakers on purpose.

[NB-SK]

Quick question about speaker matching and cabinets:
I've only ever had identical speakers in multi-speaker cabinets...
So, does power rating of two (or more) speakers in the same cabinet have to be matched? I've heardof people mixing different speakers in 2x12 and 4x12s to get different types of sound but does it matter if you mix say one speaker rated at 150 W with another rated at 50W? How does that affect the amp? I'm guessing you would want the amp rating to be no more than double what the lowest power speaker can handle...? So, is the only thing that's really important to match the ohm rating?

Also, related -- I see used cabinets with or without speakers go all the time for anything from $200 up to thousands and new cabinets without speakers seem to go in the same range. (YellowCab has some very pretty cabs but they're $1100 each for a 2x12, and I think that's w/o speakers). Is there really such a huge difference in the box used to hold the speaker? I guess real wood or plywood would be preferable to some of the more chipboard-like ones but really anything else?


I know what you mean. I really can't see how anyone could justify paying that much for an empty cabinet when I could make one myself in an afternoon. Sure, if you want a fancier finish on your cab...but I really doubt that will enhance the tone.

[Wild Bill]

Quick question about speaker matching and cabinets:
I've only ever had identical speakers in multi-speaker cabinets...
So, does power rating of two (or more) speakers in the same cabinet have to be matched? I've heardof people mixing different speakers in 2x12 and 4x12s to get different types of sound but does it matter if you mix say one speaker rated at 150 W with another rated at 50W? How does that affect the amp? I'm guessing you would want the amp rating to be no more than double what the lowest power speaker can handle...? So, is the only thing that's really important to match the ohm rating?

Also, related -- I see used cabinets with or without speakers go all the time for anything from $200 up to thousands and new cabinets without speakers seem to go in the same range. (YellowCab has some very pretty cabs but they're $1100 each for a 2x12, and I think that's w/o speakers). Is there really such a huge difference in the box used to hold the speaker? I guess real wood or plywood would be preferable to some of the more chipboard-like ones but really anything else?

A power rating tells you how much power the speaker can safely handle. Power is pushed, not drawn so it doesn't matter what the power rating of the speaker is, as long as it's more than the highest power you expect to push into it.

When you combine speakers the power splits. If they are both the same impedance then the power will split equally. So if you have a 2-12 with two 8 ohm speakers in series or parallel they each will see half of the power. This means that if you use a 150 watt speaker and a 50 watt unit the power will be split equally. If you drive more than 100 watts the 50 watt unit will start to see too much power and could burn out. You would have to rate the cab at 100 watts, despite having a total power rating of 200 watts.

If you combine speakers with different ohm ratings the lower ratings hog the power. Just how much requires some ugly math.

As for wood, the simple answer is that a cab is supposed to be as stiff and rigid as possible. Otherwise the walls will vibrate in sympathy with the lower bass notes. This sucks up the acoustic energy, hurting the volume.

Obviously, you want a dense wood with no "holes" or voids inside. So cheap plywood would be a "no-no" but more expensive Baltic birch would be great! Oak would be super but it's heavy and expensive.

Everybody's looking for the mythical 4-12 cab that works great but weighs 5 lbs, including speakers!:smile: Mythical indeed. Good quality particle board can be strong and light. As long as it never gets wet it will stand up just fine over the years. Some particle boards are better than others. You can use thinner boards if you have smart bracing inside. If you open up a vintage Marshall 4-12 you'll immediately see how there's a strut connecting the front baffle to the back cover. This helps cut vibration and lets them use thinner boards.

If you look in books from the glory days of hifi for DIY construction projects of speaker enclosures you'll see plans using 3/4" pine for 50 watt max cabs. Some designs went so far as to use two 1/2" boards separated by 1" dowels like a sandwich. Or spaced an inch apart and the space filled with dry sand! These cabs were BIG! Maybe 3 or even 4 feet high and a couple of feet wide and deep! They might weigh 200 lbs if they had sand-filled walls. This wasn't overkill. They wanted totally rigid walls for maximum low end efficiency.

Compared to those little crap boxes you buy in stores today that need a 400 watt receiver to be heard in an apartment those old designs sounded GLORIOUS! Modern designs have traded tone and efficiency away to make products that are small, light and "cute".

Guitar speakers don't have to reproduce the low bass notes of a hifi system so they can get away with less drastic methods. Still, being "stiff" matters!:smile:

:food-smiley-004:

[NB-SK]

"Good quality particle board can be strong and light. As long as it never gets wet it will stand up just fine over the years."

Not that most people need to worry about this. It's so humid here in the summer, I've had leather jackets, belts, and shoes turn a moldy green...but my little 20 watt tube amp hasn't fallen apart yet...and the cab is particle board.

[nonreverb]

Quick question about speaker matching and cabinets:
I've only ever had identical speakers in multi-speaker cabinets...
So, does power rating of two (or more) speakers in the same cabinet have to be matched? I've heardof people mixing different speakers in 2x12 and 4x12s to get different types of sound but does it matter if you mix say one speaker rated at 150 W with another rated at 50W? How does that affect the amp? I'm guessing you would want the amp rating to be no more than double what the lowest power speaker can handle...? So, is the only thing that's really important to match the ohm rating?

Also, related -- I see used cabinets with or without speakers go all the time for anything from $200 up to thousands and new cabinets without speakers seem to go in the same range. (YellowCab has some very pretty cabs but they're $1100 each for a 2x12, and I think that's w/o speakers). Is there really such a huge difference in the box used to hold the speaker? I guess real wood or plywood would be preferable to some of the more chipboard-like ones but really anything else?

One thing I would add here is that speakers of different wattage ratings are designed for just that. Using a 50W and a 150W speaker both @ 8 ohms won't sound the same for the simple reason that the higher wattage speakers voice coil is gonna be heavier. This means that a portion of the power will be lost moving a speaker whose assembly is more massive. Plus getting it to distort won't be easy. Its gonna sound different...you may like it....you may not.

[whammybar]

You might want to look at the tiny book London Power Speaker Cabinets for Musical Instruments by Kevin O'Connor. Explains all you need to know on mixing drivers (you might need a capacitor on the smaller speaker to keep the bass note from tearing it apart) and building spraker cabinets. They may not be light but the will sound great.

[dwagar]

I think the efficiency of the speaker makes a difference too, the dB rating.

A high efficiency speaker can walk all over a low one.

Course, I could be wrong, just my understanding of it.