Speakers: Dispersion vs Directionality?

  • Thread starter Thread starter cephus
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cephus

cephus

Slow Children Playing
OK. Maybe it's not a word.

I played a gig this weekend in a weird shaped room and found that my 212 peavey classic 50 had a 10-degree range where i could hear it. I mean, 20 feet away, if I walked in an arc, it was like a 10-15 foot range where you could hear the amp and then it dropped off - alot.

Is this a function of the shape of the speaker cabinet or is it the actual speakers? that is, would I benefit from more sound dispersion if I invested in some real speakers instead of these blue marvel things?
 
They all do that. :D

Seriously, my understanding is that high-frequency drivers tend to be very directional, and low-frequency drivers are less so. Nevertheless, all speaker enclosures (except subwoofers, really) exhibit noticeable directionality.

The farther away you stand from the source the less you notice it, because the cone of dispersion widens with distance, and the refraction from off-stage stuff causes all the sound to bounce around and get blended together.

That's my experience, anyway.
 
Cephus, speakers have a polar response in the same way that a mic does. You only get the "true" sound directly in front or a few degrees off-center.

With stereo speakers, you will notice the high-end stuff drops off first as you move off-axis, followed by midrange and low-mids. With a guitar speaker, you mainly notice a decrease in volume.
 
If you like the sound of the blue marvels, I'd say try C7us's suggestion and mic the amp to provide more coverage. Some temporary cardboard and duct tape will probably give you a good idea of what the beam blockers are going to do. Personally, I hate the way blue marvels sound..........very ice picky to my ears.
 
I ended up micing it event though it wasn't a big space. It was just a LONG space. My main concern is that some poor stiff would get his head cut off by my amp, which seems perfectly tame to my half-deaf ears. I have to be careful that the amp doesn't point directly at innocent bystanders. I don't know if the blue marvels sound like ass or not. i feel like I am getting a good tone from it, but I really have only had 10 gigs or so since I bought it. And there have been spotty reports of my amp being way too fucking loud. It just seems like this new amp is hotter and way more directional than the old one (which was essentially the same cabinet architecture).
 
I've noticed this too from some amps. I think guitarists should have their amps up on stands and angled at the back of their heads so they bear the brunt of the strongest energy coming from the speaker.
 
This illustrates one advantage of micing your amp - your sound is a lot easier to control and blend with everything else. Sometimes it's really tough to do in small rooms, and still get a decent sound out of your amp.
 
c7sus said:
Try a beam-blocker from Ted Weber.
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Looks like a cool screw-on accessory that strat-guys like. For some reason $36 seems steep to me.
 
c7sus said:
Call Ted Weber. He answers the phone. Tell him what's up and he'll fix you right up.

http://www.tedweber.com/
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What I don't see is any empirical information on how sticking that thing in front of a speaker affects its frequency response on-and off-axis. A simple before-and-after graph of spl taken on axis and off-axis for various points in the response spectrum would do. It should be simple enough, and considering that he designs amps you'd think he'd have the measurement equipment.
 
So you just want something that projects farther

not wider, right?

If you wanted wider, I'd say a second cab and then angle them.

If you just want longer, then you're probably screwed. You can mic it up, if you can, but I'm guessing your PA is suffering the same problem. You can run a second set of smaller PA speakers to that back of the place and turn them down (it's kinda like doing monitors), but that's a pain and you'll probably piss somebody off. A lot of folks stay in the back because they don't want to hear the music that loud. They're regulars there to socialize and play pool or whatever. You're just a background diversion, and if they can't talk over you, they'll go elsewhere, which the owner won't like at all.
 
It stops the hi's from directly piercing your ear drums. What more do you need to know? :D
 
I am going to play around with some duct tape and styrofoam to see if it makes any difference. It looks like it would work, doesn't it?
 
cephus said:
I am going to play around with some duct tape and styrofoam to see if it makes any difference. It looks like it would work, doesn't it?
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Those beam blockers are a speaker dust cover with probably a piece of thin guage sheet metal for the support that gets screwed down. You could probably just use some tape. Might as well play around with different stuff around the house and see what happens.
 
I put a set on and I'll say that it didn't remove the directionality of the speakers out but it did break up the harsh ice picking highs from piercing through quite as much. If this is a big problem, consider an open back cabinet.
 
Yes it is open back. Maybe the ice pick thing is what needs addressing.
 
cephus said:
Yes it is open back. Maybe the ice pick thing is what needs addressing.
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I don't have any ice pick sounding speakers any more. If you don't mind, let us know how the tape (or whatever you use) works out. I'm curious to know how much of a difference it makes on those blue marvels.
 
Well, like someone already pointed out, speakes by nature are directional you're gonna get that. Probably less so at lower freqs and perhaps more noticeable at the high freqs.
 
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