BillFitzmaurice.info

5meohd wrote:I actually tried to look into it and it does seem that a LOT of super hi fi loudspeakers are indeed MDF.

True. Because it's cheap and it takes a veneer well.

this dude is actually trolling hard enough to post directly on my facebook wall

So what? Unless his name is Tom Danley, Don Keele, Joe D'Appolito, Andrew Jones, or perhaps Bill Fitzmaurice, his opinion about speaker design is of absolutely no consequence.

I just hate to have potential customers or even friends reading his posts causing them to hear with there eyes.

Just post the following two links. If MDF is so great, why does JBL only use it in the cheap consumer-grade gear and plywood for all of their pro sound gear?

Here's JBL's foreign-made crap - all MDF
http://www.jblpro.com/catalog/general/P ... =452&MId=3

Here's their newest pro-line series (along with the Vertec boxes) - all plywood.

http://www.jblpro.com/BackOffice/Produc ... 825.v8.pdf

You'll find the same for every name-brand manufacturer out there. MDF goes in the junk and plywood in the good stuff.

Bruce Weldy wrote:Just post the following two links. If MDF is so great, why does JBL only use it in the cheap consumer-grade gear and plywood for all of their pro sound gear?

Here's JBL's foreign-made crap - all MDF
http://www.jblpro.com/catalog/general/P ... =452&MId=3

Here's their newest pro-line series (along with the Vertec boxes) - all plywood.

http://www.jblpro.com/BackOffice/Produc ... 825.v8.pdf

You'll find the same for every name-brand manufacturer out there. MDF goes in the junk and plywood in the good stuff.

I love the quote on that MDF box... Marketing wankery is added to everything these days innit?

The rugged, acoustically superior enclosure is constructed from 19 mm (.75 in ) MDF (Medium Density Fiberboard) using advanced adhesives and mechanical fastener technology for extreme durability and improved low-frequency performance.

5meohd wrote:I just hate to have potential customers or even friends reading his posts causing them to hear with there eyes.

I understand what you're saying.

I was going to write an essay, but restrained myself.
Honestly, block the guy's posts. You're not going to convince him that anything other than MDF is better, and he's not building or running your system and probably never heard a BFM system before.
And if he does, tell him you took his advice and made it from MDF

I'm wondering if the real problem is you are half believing what he says and wondering if you should have used MD to build. NO!

Michael Ewald Hansen wrote: There's a reason professional and high performance speakers from pretty much all brands are made out of plywood - its much much more durable and weighs way less, albeit at a cost, because good quality plywood is way more expensive than MDF..

+1

88h88 wrote:using advanced adhesives and mechanical fastener technology

Translation from marketspeak: Glue and staples.

There is an engineering answer to this:
In simple terms, heavy things don't move readily when subjected to excitation forces.

And on a second analysis, there may be a feeling that MDF has better internal damping and/or lower stiffness than ordinary plywood - these would limit resonance and lower natural frequency respectively, but would have to be proven by measuring response to a vibration input, in comparison with other speaker materials. The quantitative assessment or comparison of materials would yield nothing useful. In good speaker design, panel dynamic vibrations are controlled to be so low that they have no influence on acoustics.

I've heard that about MDF before, have you found any evidence to back it up? I only use well-braced cabinets and never had any issues with resonance.

I haven't looked for any evidence. I just know a little bit about vibration and engineering and have intuitively applied it - there is possibly literature in the public domain.

Whilst linked through physics, the subject of acoustics is a different discipline to mechanical component or assembly vibrations. The link to acoustics is that while a machine or component may vibrate severely, you will only hear it inasmuch as the radiating surfaces effectively couple to the air and generate some spl in audible frequencies.

Acoustic foam/damping should not be underestimated, though i expect they have more to do with mitigating standing waves than panel vibration contributions.

Charles Jenkinson wrote:There is an engineering answer to this:
In simple terms, heavy things don't move readily when subjected to excitation forces.

There is a cost analysis answer to this: MDF is cheap. You can use it in 3/4 inch or thicker to slap together a cabinet with little or even no bracing that will function reasonably well. But it will not be durable and will weight a ton.
Plywood is much more expensive than MDF, and bracing greatly increases the build time and labor costs. You end up with a very durable and lightweight cabinet, but it's a lot more expensive.

You get what you pay for.

Charles Jenkinson wrote:There is an engineering answer to this:
In simple terms, heavy things don't move readily when subjected to excitation forces.

Neither do well braced, light weight things.

It's ok, just call me Charles.

Charles Jenkinson wrote:It's ok, just call me Charles.

Naa, I'll call ya that bloke, CJ from UK! LMFAO!

Charles Jenkinson wrote:It's ok, just call me Charles.

Yes, mr Jenkinson