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[Duane Massey]

I suspect most plastic cabinets sound "bad" because they are using components that are not exactly high$$.

Properly built, a plastic box should work just as well as a wooden box (or a concrete box, or a particle board box), UNLESS you want the particular resonance as a mater of taste.

I have always striven to avoid any resonances in the cabinets I build, preferring a box that will output what is input.

[Bob Josjor]

Duane Massey wrote on Sun, 07 November 2010 20:08

I suspect most plastic cabinets sound "bad" because they are using components that are not exactly high$$. Properly built, a plastic box should work just as well as a wooden box (or a concrete box, or a particle board box), UNLESS you want the particular resonance as a mater of taste. I have always striven to avoid any resonances in the cabinets I build, preferring a box that will output what is input.

The aforementioned Impulse 1015's at least have decent components: Black Widow and 22XT.  The whole resonance issue would be my complaint on most of the plastic boxes out there.  The Impulses are pretty solid, but if you compare them to the Peavey PR series (which, to be fair, is less than half the cost) there is so much bleed back of bass from the cabinet flex that they become extremely muddy when fed any low end.

[Chuck Simon]

I don't doubt that "really good" cabinets made from plastic could exist, it just doesn't seem like anyone is making professional grade,  high end cabinets out of plastic yet, or am I just not aware of them?  It probably is the future!

[Duane Massey]

Bob, you are correct. I should have said that corners cut to aid the fabrication process to save $$ can certainly make for significant problems as well.

Although not "plastic" the old Community designs that were almost 100% fibreglas certainly did not have serious resonance issues, but they were not cheap.

[John Roberts {JR}]

Bob Josjor wrote on Sun, 07 November 2010 21:22

The aforementioned Impulse 1015's at least have decent components: Black Widow and 22XT.  The whole resonance issue would be my complaint on most of the plastic boxes out there.  The Impulses are pretty solid, but if you compare them to the Peavey PR series (which, to be fair, is less than half the cost) there is so much bleed back of bass from the cabinet flex that they become extremely muddy when fed any low end.

While I don't know what's inside the current 1015, as i recall the original impulse 500 had a internal wooden strut to prevent a bass robbing cabinet resonance..

Hybrid ??  Mixed technology...

JR

[Milt Hathaway]

Chuck Simon wrote on Sun, 07 November 2010 21:50

I don't doubt that "really good" cabinets made from plastic could exist, it just doesn't seem like anyone is making professional grade,  high end cabinets out of plastic yet, or am I just not aware of them?  It probably is the future!

Here's one: http://www.electro-voice.com/product.php?id=414

I'm not certain of your definition of "professional grade" but I will say that mine are making me money and satisfying my customers.

[Chuck Simon]

Well if they are making you  money then I guess they are "professional grade" but I think you know what I mean.  The really high end, state of the art speaker systems still seem to be made of wood.  I think that will change.

[Art Welter]

Chuck Simon wrote on Sun, 07 November 2010 18:57

Bob Josjor wrote on Mon, 08 November 2010 00:05 Seth Hochberg wrote on Sat, 06 November 2010 23:14 There are good wood PA cabs, and there are plenty of bad ones. There are good plastic PA cabs, and plenty of bad ones of those, too. We have a winner!!! There are lots of general statements that may apply (wood is heavy, plastic flexs too much, etc) but the above statement is the only truly correct one. Really?  What are some of the really good plastic ones?  Who is using them?

Sound Image had plenty of really good touring cabinets made of plastic, though not the usual plastics. They use foam core, covered with glass fiber, similar to boat construction.

Wood is a lousy material to make cabinets from, as it is resonant.

Plywood alternates layers of wood, grain running at 90 degrees opposite in each layer,  making it far less resonant, so it is a good cabinet material. The glue that holds plywood together is basically plastic.

Baltic Birch is great for cabinet building because it has more plys and lots of glue.

Plastics have the advantage of being able to mold bracing and compound curves into the material, but that greatly increases the cost of the mold, and the difficulty in injection, making it very expensive relative to a plywood construction.

Proper bracing can eliminate lots of material, wood or plastic, and can net better sounding lighter results.
However, that bracing adds construction time, complexity and expense, which few are willing to pay for.


Art Welter

[Chuck Simon]

I have a little GK bass amp with an aluminum cabinet.  It sounds amazingly good for it's size.  Any thoughts on Aluminum as a cabinet material?

[John Roberts {JR}]

Chuck Simon wrote on Wed, 10 November 2010 08:26

I have a little GK bass amp with an aluminum cabinet.  It sounds amazingly good for it's size.  Any thoughts on Aluminum as a cabinet material?

I think I recall some small rat shack speakers in a metal box.

Back in the '80s a tech working for me was into DIY speakers, and he played around with wood that had metal laminated on the surface. As I recall, the metal was pretty thin and probably didn't change the character of the box.

For lead guitar amps the box is a large part of the sound so even the type of wood used matters, for a bass guitar amp the desired output is generally cleaner so it seems a very dead box would be preferable. A wood cabinet flexing, is absorbing energy that would otherwise come out the front as sound pressure level. So metal would make great sound reinforcement speaker cabinets if it wasn't so heavy and/or expensive.

JR