Boxes or Not

[joaquim]

Thread split off from http://www.diyaudio.com/forums/full-...t=wood+varnish

Hi guys!
I'm new to this thread as well, but I've build speaker cabinets, speaker elements(I've wind the coil myself and then I buy the cone, the suspension, the magnet, basket etc., I'm "tube-crazy", so it's a great way to get the perfect match for the output trafo and speaker, all properties of the speaker, from induction to Vas, is under your "spell" - ctrl).
There's so many different opinion and ways to choose the "right" material as there are "builders/designers".

Personal I all most always use MDF and sheep wool. I've experimented with concrete, black-oak etcetera. To put all the resonance frequencies to use, in some fashion... And I've manage to get a small 4" full range speaker, to produce base like an 18", but I always end up building(for those who order amps and speakers from my little company) cabinet with MDF, and then "dress up" the cabinet with, whatever wood the customer/you want, except for the front, because if you use a very hard wood(or fiberglass, eeekh... what a terrifying thought....) the measured values of the speaker-element in question will change. What you get from the datasheet of a speaker-element is based on an infinity baffle, absolutely no resonance fq from the cabinet.
What you want to do with your cabinet is to change those data, and perhaps get a higher resolution from the base/mid-range element(s), or for a subwoofer, you might want to force the element to play beyond its resonance frequency, and so on...

My advice for beginners is to use MDF and veneer, and closed or ported cabinets. And of course, use the Volume(liters) specified in the datasheet, a ported cabinet always becomes much bigger than a closed, depending on the ports length and diameter... A vented speaker, is often much "easier" to drive than a closed, especially the lower frequencies... But in "my world" there's no better material than MDF to use as housing, than you can dress it with whatever your fancy, veneer, plywood, "real" black-oak, mahogany, cherry bla bla bla.... And there are many "damping materials", but I found that real wool is the best, but I'm very old fashioned... there are synthetic damping that are many times superior to wool!

But wool and MDF and "mid-fi"-speakers, like Zachery, Vifa(they have many hi-fi elements too, though I'm Swedish, the Danish knows how to make speakers!) , Scanpeak, Preeless and even Cerwin-Vega(though I've never "understood" their slogan, "Loud and Dirty"... but that's just me...).
And A closed or vented cabinet is a good beginning, and don't use too elaborate filters, a 12dB/Oct and a Zobel is often enough. To start with, I would use a 6dB/Oct, damping and Zobel, and only Zobel on the base/mid-range speaker if you're building a two-way speaker...

Zobel/Passive/Low/Bandpass/High - link
Visit ESP, you can get much good ideas and info there!

Have fun, "try and error" is my way, and the best way, build, build and build, each mistake will learn you something new!

[dave w p]

The cabinet should add nothing at all to the sound. It's like years ago when radiograms were said to have a nice tone, any resonance will add something that shouldn't be there. Just listen to a pair of electrostatics with no cabinet to prove my point.

The HIFI site

[chrisb]

Originally Posted by dave w p

The cabinet should add nothing at all to the sound. It's like years ago when radiograms were said to have a nice tone, any resonance will add something that shouldn't be there. Just listen to a pair of electrostatics with no cabinet to prove my point.

The HIFI site

Well, with all due respect; as with transducers with electro/magnetic dynamic motors, not all electrostatics sound the same (or would be the best exemplar of your point)

and there are some of us quite happy with the musical mirage produced by commercial or DIY enclosure designs that would not past objective measures of inert neutrality - does that make us wrong?

- keep the change

[dave w p]

I accept your point that there will always be distortion with any tranducer. As long as you're happy with your sound, then I'll be the last to offer criticism. For myself, I'm always searching for something better.
The HIFI site

[joaquim]

Originally Posted by chrisb

Well, with all due respect; as with transducers with electro/magnetic dynamic motors, not all electrostatics sound the same (or would be the best exemplar of your point)

and there are some of us quite happy with the musical mirage produced by commercial or DIY enclosure designs that would not past objective measures of inert neutrality - does that make us wrong?

- keep the change

Exactly, the electrostatic speaker can't produce any bass to speak of, check out Rod's Electrostatic project, I've build it just for fun(I found on old article from a Swedish magazine called "Radio & Television", from 1late 60's, and they had an article 'bout headphones w/ electrostatic "elements", 30k of voltage between my ears.... they must have confused it with chock thearapy.. ).

Well hears the link to a great project for those who want to hear "voltage"....
He has removed that project... sad but true.. I might have missed it so if some one's curious, the url is; ESP Projects Pages - DIY Audio and Electronics

[joaquim]

Well I found the project... yipee-kai.....
Project 105 - Build an ESL , it's a three part projcet, and notice that he use a "common" speaker for the base fq.
I recommend anyone who's never really cared or heard of electrostatic speaker to build this project, it's lots of fun, and it opens ideas for all sorts of crazy solutions...

[planet10]

Originally Posted by joaquim

Exactly, the electrostatic speaker can't produce any bass to speak of

That is completely untrue. Just like any OB the bass extension is largely determined by the size of the baffle, and the level capability by the volume displacement.

An ESL that can produce bass is usually impractically large. But they exist.

BTW: to stoke the fires, i never use MDF for boxes, finding it unsuitable. Discussion on what materials to build speakers out of

dave

[chris661]

Heard some 'statics a while ago, pretty amazing, even though they were 2-way (mid-high and mid-bass). 2' wide by 3' high, bass went low enough, loud enough. Still, while impressive to listen to, it wasn't for me.

Now then, a while ago, I played around with cancelling the rear-wave of a small full-ranger. There's a thread somewhere. Why can't such an idea be applied to electrostatics? Surely, with a light cone and a powerful motor (think PA drivers), the rearward driver would keep up...

Of course, the rearward cabinet would have to be well braced, and another amplifier would be needed, but halving the size of the electrostatic panels required would be handy...

[aptquark]

My MMG's produce excellent bass.

[joaquim]

Originally Posted by planet10

That is completely untrue. Just like any OB the bass extension is largely determined by the size of the baffle, and the level capability by the volume displacement.

An ESL that can produce bass is usually impractically large. But they exist.

BTW: to stoke the fires, i never use MDF for boxes, finding it unsuitable.Discussion on what materials to build speakers out of

dave

Well good for you, "judge the book by its cover, and read what you want between selected lines...."
Why you mentioned MDF can I only take for kindergarten sandbox war.... Build a cabinet with MDF is excellent, and then use plywood or whatever to "hide" the MDF is a cheap way to build good looking, well sounding speakers. I don't know if you have unlimited supply of money, but I don't, and I rather spend some extra bucks on the elements.....
But cheers to you mate...

And building a well sounding system with limited assets is a bigger challenge, if you have the money and can buy what the heck you want, well why even do it your self?

planet10: And why are you picking on me?