Vertical cab stacking---the only way to play

[musicman7722]

Groan, I think I'll take up the flute. To much physics here and a flute is even light than my LM amp. :} But seriously thanks to you all I've been reading these posts with great interest and a lot of coffee.

 

[ehque]

You're going to have the same problem with any configuration unless the dimensions of your speaker system are comparable to the wavelengths of interest and you're in the near field radiation pattern. At 100 Hz, the wavelength is about 11 feet! For a 4x10 cab which has dimensions of about 2' x 2' square, you're in the far field when you're about a foot away from the speaker cabinet at 100 Hz. Further than that, the cabinet acts as a point source as far as intensity is concerned, and the SPL drops as 1/r2​.

Asad

Hey, a physicist! I'm a physics undergrad. The PA where i play uses sequential-firing full range speakers that are flown above the congregation, in rows. Because they are sequential firing, or delayed, problems like "echos" or phase cancellation are minimised, and because there are so many of them, we don't have to turn up high to get to the back of the hall, preventing any one area from having very high sound energy levels.

I thought this was a very nifty way to get even sound without resorting to one-point-sources.

 

[GlennW]

Does this vertical stacking only apply to speakers with the same stuff being played through them?

Here's a simple situation with two cabs; 1x15 cab for PA and one 2x12 cab for guitar.

Should the 2x12s be vertical over the 15 for better sound distribution?

I'd think "yes" if the 2x12 is miced through the PA, but does the placement of the 2x12 matter if it isn't miced?

 

[billfitzmaurice]

Here's a simple situation with two cabs; 1x15 cab for PA and one 2x12 cab for guitar.

Should the 2x12s be vertical over the 15 for better sound distribution?

I can't see an instance where a 1x15 PA cab and guitar cab would be in the same place.

 

[ihateusernames]

maybe i missed the answer in the clutter of this thread, but these same principles apply to all loudspeaker applications, including a typical 6 string electric through a 2x12 - correct?

 

[billfitzmaurice]

but these same principles apply to all loudspeaker applications, including a typical 6 string electric through a 2x12 - correct?

Even more so, as the higher the frequency the more destructive are the results of horizontal placement.

 

[theshadow2001]

On a small stage where your close to your 2x10 where your not going to be leaping and jumping around left and right of your rig (or your just a statue player thats going to be standing close to your rig). Would it not be better to leave the cab horizontal. So that comb filtering doesn't occur in the direction of your ears i.e. up or the vertical plane. Even if you raise the 2x10 you generally don't get it to head height.

I have been in the small stage close to the rig and not much room to move anywhere with PA support quite a number of times so this isn't just an off the wall hypothetical situation.

Also what's the difference between an under developed wave and a developed wave 8 to 10 feet away?

 

[alexclaber]

Also what's the difference between an under developed wave and a developed wave 8 to 10 feet away?

That's like asking the difference between Santa Claus and The Tooth Fairy...

Alex

 

[theshadow2001]

That's like asking the difference between Santa Claus and The Tooth Fairy...

Alex

Ahh it's all so clear now

 

[billfitzmaurice]

Ahh it's all so clear now

He's saying that there's no such thing, and, like Santa and the Tooth Fairy, the 'undeveloped wave' is a fantasy, concocted to explain observed phenomena by persons who have no idea as to how sound waves actually function.

 

[A9X]

Hey, a physicist! I'm a physics undergrad. The PA where i play uses sequential-firing full range speakers that are flown above the congregation, in rows. Because they are sequential firing, or delayed, problems like "echos" or phase cancellation are minimised, and because there are so many of them, we don't have to turn up high to get to the back of the hall, preventing any one area from having very high sound energy levels.

I thought this was a very nifty way to get even sound without resorting to one-point-sources.

Thought exercise for you; if there are delays implemented electonically between horizonatally arrayed speakers, at what position in the room do you need to be for all the apparent sound sources to be in phase? Think time of flight.

On a small stage where your close to your 2x10 where your not going to be leaping and jumping around left and right of your rig (or your just a statue player thats going to be standing close to your rig). Would it not be better to leave the cab horizontal. So that comb filtering doesn't occur in the direction of your ears i.e. up or the vertical plane. Even if you raise the 2x10 you generally don't get it to head height.

No. You're vertical changes will be less and of shorter duration than any horizontal ones.

 

[theshadow2001]

He's saying that there's no such thing, and, like Santa and the Tooth Fairy, the 'undeveloped wave' is a fantasy, concocted to explain observed phenomena by persons who have no idea as to how sound waves actually function.

I wonder if the idea comes from thinking of sound as a sine wave rather than a compression wave

No. You're vertical changes will be less and of shorter duration than any horizontal ones.

But with your cab vertical and comb filtering happening up the way isn't it creating a more likely scenario that your head is going to be stuck right at a point where there's deconstructive or constructive interference. Leading you to over compensate

 

[sineas]

unless you want to use them and make them perform like a center channel... go ahead and do horizontal driver arrays... other than that, just stick to proven conventional method.

 

[A9X]

But with your cab vertical and comb filtering happening up the way isn't it creating a more likely scenario that your head is going to be stuck right at a point where there's deconstructive or constructive interference. Leading you to over compensate

The best way around any combing issues is to not use multiples if the same driver covering the same frequency range. The world has moved on from the 50's.

 

[theshadow2001]

unless you want to use them and make them perform like a center channel... go ahead and do horizontal driver arrays... other than that, just stick to proven conventional method.

Tell me more about using a horizontal array as a centre channel

The best way around any combing issues is to not use multiples if the same driver covering the same frequency range. The world has moved on from the 50's.

obviously not going by the amount of 4x10 and similar set up cabs knocking around.

 

[A9X]

obviously not going by the amount of 4x10 and similar set up cabs knocking around.

Do you see me using one?

 

[theshadow2001]

Do you see me using one?

The only thing I see you using is a set of drums in your profile picture.

Maybe you should just change your previous comment to I've moved on from 50's technology

 

[A9X]

The only thing I see you using is a set of drums in your profile picture.

That's Keith.

 

[billfitzmaurice]

The best way around any combing issues is to not use multiples if the same driver covering the same frequency range. The world has moved on from the 50's.

I wouldn't go that far, using multiple drivers vertically arrayed has its advantages vis a vis both sensitivity and pattern control.

But with your cab vertical and comb filtering happening up the way isn't it creating a more likely scenario that your head is going to be stuck right at a point where there's deconstructive or constructive interference. Leading you to over compensate

No. And there remains the narrowing of the cabs horizontal dispersion when the drivers are horizontal, which is just as much as if not more of a concern than combing.

 

[A9X]

I wouldn't go that far, using multiple drivers vertically arrayed has its advantages vis a vis both sensitivity and pattern control.

True, but best used on a scale that's far more applicable to larger venues than a typical bassist's cab needs to cover.