Building amp heads and guitar cabinets?

[Nigel Goodwin]

References please. Chipboard is c-r-a-p. Hifi is not pro audio.

MDF is used in hifi because it's cheaper and easier to machine.

You don't need references - knock on an unbraced bare plywood cabinet with your knuckles - hear the resonance. Now do the same on a similar chipboard one, notice the greatly reduced resonance. It's not rocket science!.

MDF is cheaper, is easier to machine, but also has much better acoustic properties - even top end HiFi speakers don't use plywood, as it would reduce the quality of the sound, and you don't chuck HiFi speakers in the back of a van (usually).

Plywood is used in expensive PA speakers purely for it's long lasting mechanical properties, and usually with sound deadening material added to the panels, or the acoustic colouration just ignored.

What a lot of horsecrap.

In what way?, it's a true story, and every comment was true.

 

[SemperFi]

Regarding ply vs MDF there was some Finnish dude who researched extencively and the conclusion was that ply is best in all respects when the material is over a certain thickness. I cannot remember what the thickness was, but I think it was around 18mm.
My own experiences having built with both ply and MDF is that I prefer ply. Like Brett said, I agree the MDF is used in HiFi mainly b/c it's easier to build with and is cheaper.

Regarding building guitar cab, an option to tolex covering is either just staining the plywood and clearcoating, or cover with a thin layer of a wood like mahogany. I find it easier, and to me better looking.

 

[Brett]

You don't need references - knock on an unbraced bare plywood cabinet with your knuckles - hear the resonance. Now do the same on a similar chipboard one, notice the greatly reduced resonance. It's not rocket science!.

I never do unbraced cabs. Never. MDF has a much longer decay. Measurements in the new year. Too many other things to do at the moment.

Plywood is used in expensive PA speakers purely for it's long lasting mechanical properties, and usually with sound deadening material added to the panels, or the acoustic colouration just ignored.

Ply is used in everyrhing except the cheapest garbage cabinet. I don't remember the last time I opened up a quality cab and saw panel damping.

 

[John Audio]

Towards the end of the summer I went to the PLASA exhibition in London and saw lots of Pro Audio PA speaker cabinets - and most of them (and all the good ones) - were made of birch ply......

On the subject of Hi Fi cabinets, some of the best speakers of all time (various BBC monitors made by Spendor, Rogers and Chartwell etc) were made of - guess what - birch ply.....!