Phasing, and dispersion ?

**fuzzy beard** · #1 08-23-2011, 06:20 PM

I dont have the most savvy ear but i have read on here countless times about phasing and dispersion issues with bass cabs. Most commonly about 2 2x10 stacked verticaly is better than the common 4x10.

So what are you really changing by stacking 2 2x10s. If i understand what is being said about a 4x10 then a 2x10 should be no different. You still have sound waves hitting each other from a 2x10!

So i would think that 2 2x10s stacked would make for a very uneven sound despersion. Speaker 4 is effected by only speaker 3. Speaker 3 is effected by speaker 4 and 2. Speaker 2 is effected by 3 and 1. And speaker 1 is effected by speaker 2and the floor.

So if you were able to understand that ^^^^. What am i missing i just dont understand!

Also i know none of this matters as long as you like the sound but the tech side of cabs really has my intrest!

BogeyBass · #2 08-23-2011, 06:30 PM

it just changes the dispersion pattern.

otherwise unless your audience is under the stage or hanging from the ceiling, the standard 4x10 works fine.
otherwise for the most part standing in front of it, sounds the same.....move to the left or right sound changes.
vertical stack will help others to the sides hear you better.

im looking for some links that might help you see it...hang on

Tunaman · #3 08-23-2011, 06:38 PM

AMP FAQ bro... I researched for a few hours today & got my answer to a different question. Rock on

Bassamatic · #4 08-23-2011, 06:38 PM

Every speaker interferes with every other one by causing phase adding and canceling that you might hear as you move around. When they are vertical, the phase issues are up and down where they are less likely to be heard. This only occurs at higher frequencies that are equal to or shorter than the distance between the drivers. Stacking the drivers also creates an acoustical phenomenon that causes a wider natural dispersion, which is why most PA speakers are columns.

Tunaman · #5 08-23-2011, 06:44 PM

Quote:

Originally Posted by Bassamatic

Every speaker interferes with every other one by causing phase adding and canceling that you might hear as you move around. When they are vertical, the phase issues are up and down where they are less likely to be heard. This only occurs at higher frequencies that are equal to or shorter than the distance between the drivers. Stacking the drivers also creates an acoustical phenomenon that causes a wider natural dispersion, which is why most PA speakers are columns.

Great post boss, you deserve a kiss!

BogeyBass · #6 08-23-2011, 07:18 PM

Here i used this java applet which is a basic 3D sound wave simulator.
keep in mind that you of course need java enabeled and a browser that supports it....otherwise nothing will pop up..

I used higher frequency and used enough separation to make everything as obvious as possible.

here is 2 sources placed side by side or horizontal, you can see strong lopes that extend vertical.....hitting things such as ceiling or stage.

Flip those 2 sources to a vertical stack, and the strong lopes now extend horizontal,...hitting things such as fellow band members, or audience.

billfitzmaurice · #7 08-23-2011, 08:42 PM

Quote:

Originally Posted by fuzzy beard

So what are you really changing by stacking 2 2x10s.

Midrange dispersion is inversely proportional to the width of the source. That makes the midrange dispersion angle of vertically stacked 2x10s twice that of a 4x10. Combing is a relatively minor issue compared to dispersion, but where that's concerned the applet shown by Bogey Bass does not work as he states. The views of the applets are top views, not side views, showing how the waves interact in the horizontal coverage zone. To see the effect of vertical stacking in the coverage zone you'd look at the single point source radiation pattern, as vertically stacked drivers have the same horizontal dispersion pattern as a single driver.

**fuzzy beard** · #8 08-24-2011, 05:24 PM

So are you saying the same 2x10 will have better dispersion standing verticaly than sitting horizontal? I am having a hard time getting my mind around that.

GrowlerBox · #9 08-24-2011, 05:29 PM

Quote:

Originally Posted by fuzzy beard

So are you saying the same 2x10 will have better dispersion standing verticaly than sitting horizontal? I am having a hard time getting my mind around that.

The vertical speaker arrangement will have better horizontal dispersion, but worse vertical dispersion, which doesn't usually matter, unless you and/or the audience are being raised and lowered on a gantry during your performance.

If you can understand why a single large speaker has a narrower dispersion angle for mids/highs than a smaller one does, then think of a 210 as being a 10-inch speaker on one axis, and a 20+-inch speaker in the other; two small speakers behave as one large one when arranged side-by-side.

**fuzzy beard** · #10 08-24-2011, 05:42 PM

Ok so like how 18s will beam. And they say a 4x10 will mimic the beaming of a larger speaker(18 or bigger). So what we are getting into is off axis effect of speaker placment. It may sound good right infront of it but if you have it vertical or horizontal will effect how it will sound if you move one way or another!

GrowlerBox · #11 08-24-2011, 05:45 PM

Quote:

Originally Posted by fuzzy beard

Ok so like how 18s will beam. And they say a 4x10 will mimic the beaming of a larger speaker(18 or bigger). So what we are getting into is off axis effect of speaker placment. It may sound good right infront of it but if you have it vertical or horizontal will effect how it will sound if you move one way or another!

Zigaxly.

**fuzzy beard** · #12 08-24-2011, 06:08 PM

Thanks growler box and to all that helped! And BFM if your ever look to pass that knowledge on shot me a PM. Cab design really has really got my attention!

runmikeyrun · #13 08-24-2011, 08:04 PM

I don't understand the big deal. I've had so many different types of cabs over the years, with different heads and different tones. I've stood them up, laid them down, split them on both sides of the stage, and put them right next to each other. I've practiced in block walled basements and carpeted jam spots. I've put my cab in the corner, on a chair, and against a wall. I've had a million "your tone is amazing!" comments, even from sound guys, after we play live. No one has ever come up to me and said "you know, if you stack your cabs like this..."

I've also never ever had issues recording due to cab placement or the way the speakers were arranged.

Personally, i think it's cork sniffing and not something that anyone notices. It's like people swearing by certain chips in their tubescreamer, or having those magical NOS transistors in their Fuzz Face. Blind listening tests prove almost no one can hear any difference. So just use what you think sounds best. Personally I think (2) 2x10 stacked vertically on top of each other looks strange and wimpy.

BurningSkies · #14 08-24-2011, 08:13 PM

Quote:

Originally Posted by runmikeyrun

I don't understand the big deal. I've had so many different types of cabs over the years, with different heads and different tones. I've stood them up, laid them down, split them on both sides of the stage, and put them right next to each other. I've practiced in block walled basements and carpeted jam spots. I've put my cab in the corner, on a chair, and against a wall. I've had a million "your tone is amazing!" comments, even from sound guys, after we play live. No one has ever come up to me and said "you know, if you stack your cabs like this..."

I've also never ever had issues recording due to cab placement or the way the speakers were arranged.

Personally, i think it's cork sniffing and not something that anyone notices. It's like people swearing by certain chips in their tubescreamer, or having those magical NOS transistors in their Fuzz Face. Blind listening tests prove almost no one can hear any difference. So just use what you think sounds best. Personally I think (2) 2x10 stacked vertically on top of each other looks strange and wimpy.

Who cares if it looks wimpy if it sounds better...having speakers that are designed with sound acoustic principles has shown me that these things make a difference. Of course, if you're standing 6 feet in front of your amp, not much will matter, but out in the room, it definitely sounds better. If sounding better is 'cork sniffing', so be it.

billfitzmaurice · #15 08-24-2011, 08:18 PM

Quote:

Originally Posted by fuzzy beard

I am having a hard time getting my mind around that.

Most people do, mistakenly assuming that radiation from sound sources is the same as radiation from light sources. It isn't. For an in depth examination of what works and why, and what doesn't and why, this is an excellent source. It deals specifically with PA, but the physics is the same, all that differs is that PA systems are larger.
http://www.gtaust.com/filter/05/07.shtml
Did I Hear Someone Say “Line Array?”

**fuzzy beard** · #16 08-24-2011, 08:45 PM

Quote:

Originally Posted by runmikeyrun

I don't understand the big deal. I've had so many different types of cabs over the years, with different heads and different tones. I've stood them up, laid them down, split them on both sides of the stage, and put them right next to each other. I've practiced in block walled basements and carpeted jam spots. I've put my cab in the corner, on a chair, and against a wall. I've had a million "your tone is amazing!" comments, even from sound guys, after we play live. No one has ever come up to me and said "you know, if you stack your cabs like this..."

I've also never ever had issues recording due to cab placement or the way the speakers were arranged.

Personally, i think it's cork sniffing and not something that anyone notices. It's like people swearing by certain chips in their tubescreamer, or having those magical NOS transistors in their Fuzz Face. Blind listening tests prove almost no one can hear any difference. So just use what you think sounds best. Personally I think (2) 2x10 stacked vertically on top of each other looks strange and wimpy.

First off if you read the last line of the OP you will find I already knew what you were trying to share. But like I said the tech side of cabs and amps for that matter has become very interesting to me. And I am young (25) but learned a long time ago looks don't mean much in the end!

steve_rolfeca · #17 08-24-2011, 08:54 PM

The other issue with vertical stacking, is that the cabs stand a little taller. Makes it easier to hear yourself...

JimmyM · #18 08-24-2011, 11:03 PM

Quote:

Originally Posted by runmikeyrun

I don't understand the big deal. I've had so many different types of cabs over the years, with different heads and different tones. I've stood them up, laid them down, split them on both sides of the stage, and put them right next to each other. I've practiced in block walled basements and carpeted jam spots. I've put my cab in the corner, on a chair, and against a wall. I've had a million "your tone is amazing!" comments, even from sound guys, after we play live. No one has ever come up to me and said "you know, if you stack your cabs like this..."

I've also never ever had issues recording due to cab placement or the way the speakers were arranged.

Personally, i think it's cork sniffing and not something that anyone notices. It's like people swearing by certain chips in their tubescreamer, or having those magical NOS transistors in their Fuzz Face. Blind listening tests prove almost no one can hear any difference. So just use what you think sounds best. Personally I think (2) 2x10 stacked vertically on top of each other looks strange and wimpy.

Um, actually they look pretty doggone badass IMHO...

But while Bill and the other engineer types on here describe the way speakers behave accurately, many folks feel the same way you do and they're not exactly wrong. I pick and choose...for example, I set up my rigs to be as acoustically "correct" as they can, but if they're not, it doesn't bother me, except for phasing. Any sort of uneven response drives me nuts, so I avoid rigs that have the potential for phasing like mixed cab rigs. And I like vertical stacks because it gets a speaker pointed at my ears and I can hear what's really coming out of my amp a lot better. But narrow dispersion of mids and highs doesn't bother me much, partly because I almost always mic into the PA, but also because your more common bass cab designs like 810's and 115's define what I and a lot of people consider great bass sound.

But the more you know, the better off you will be, and while the audience may not be able to tell the difference between a vertical stack and a horizontal stack, they will be puzzled as to why they stand in one spot and hear nothing but bass, them move 3 feet away and not hear any bass at all. If you just throw speakers up on a stage and don't bother to learn any of that stuff, you won't be able to fix it. But if you learn a few things about how audio works, you can easily fix it and make your stage sound even better in the process. Don't kid yourself...audiences may not know why stuff doesn't sound good, but they know when it doesn't. And don't knock knowledge...it's a good thing.