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Re: Pro 4 + seven midhorn and tweeter [message #51019 is a reply to message #51015]

Tue, 24 April 2007 18:12

beto1
Messages: 36
Registered: May 2009

Baron

Hi Wayne,
thanks for answer.
Do you believe that MDF has good enough sonic properties comparing with other woods (including plywood boeards)?
And last, I am wondering if will be better to place the tweeter inside or outside the the bass bin, for a 4 Pi pro, following the 7Pi with no corners arrangement.
Regards,
Beto

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Re: Pro 4 + seven midhorn and tweeter [message #51021 is a reply to message #51019]

Tue, 24 April 2007 20:20

Wayne Parham
Messages: 18783
Registered: January 2001

Illuminati (33rd Degree)

The mouths of the midhorn and tweeter must be flush and physically close. The midhorn should be above the woofer and within a couple feet of it. Within these constraints, you can place the components wherever suits you best.

As for wood, acoustically, MDF is great. It's made of dust from many fibers bound with glue, so it's inherently non-resonant. But it's not very durable as a piece of furniture. Even if you never get it wet, in humid environments the wood will swell enough that butt joints will show through veneer - you'll see the seams. I think MDF is better acoustically than the best plywood, but it's heavier and less durable. I'd never build a basshorn out of it because of that, but if you use the right joints, it makes a good home hifi speaker.

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Re: Pro 4 + seven midhorn and tweeter [message #51023 is a reply to message #51021]

Wed, 25 April 2007 20:31

beto1
Messages: 36
Registered: May 2009

Baron

Hi Wayne,
Nice to hear that is a very good acoustic material. well, many speakers builders use it, of course. I'm agree also with you. I know this material used in furniture: must be used just in controled miousture enviroments but is very easy to work with. I have used extensivelly in my job (architect). I believe that used with veneer will looks very well.
Regards

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Re: Pro 4 + seven midhorn and tweeter [message #51030 is a reply to message #51023]

Mon, 30 April 2007 05:58

dB
Messages: 234
Registered: May 2009

Master

I am pleased to know you are an architect too.
Please check the website for WISA Wood Products and WISA-Form Birch (http://w3.upm-kymmene.com/upm/internet/cms/upmcms.nsf/$all/bd7ff5a1982377fac225704600368554?OpenDocument&qm=menu,4,5,0&smtitle=Plywood)

WISA Wood Products

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Re: Pro 4 + seven midhorn and tweeter [message #51032 is a reply to message #51030]

Tue, 01 May 2007 09:03

beto1
Messages: 36
Registered: May 2009

Baron

Hi dB,
thanks for the link. Very impressive products. Here we have also phenolic plywoods used for concrete work (now I'm use it) , but I'm affraid that ours are made with pine. The point is , as far as I know, veneers fibers homogenity to avoid unwanted voids.
I will check tomorrow at work, how good can be our phenolic boards for speakers matters.
Having also MDF here, of course, it will be a nonsense import baltic birch or othe fine board, by the way. Maybe we can add some sealing product before apply the venners to increase moisture protection. Also, we can use some poliurethane treatment over the venners to add the wanted finish and protection.
Best for you.
p.s. wich Pi speakers do you have or proyect it?

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Re: Pro 4 + seven midhorn and tweeter [message #51033 is a reply to message #51032]

Tue, 01 May 2007 14:57

dB
Messages: 234
Registered: May 2009

Master

Check also maritime plywood.
If you work with a CNC factory they can do joints and (I know about 3 different types of joints they make previous of) finishings with venners the way you want. They also work with MDF and plywood. The phenolic boards might work well, if well insulated against vibration (this is only my guess). There are plenty of colours and finishings. There are plenty of boards they use for outside, including maritime ply and phenolic, in construction.

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Re: Pro 4 + seven midhorn and tweeter [message #51034 is a reply to message #51033]

Tue, 01 May 2007 18:23

beto1
Messages: 36
Registered: May 2009

Baron

Hi,
yes, also I have used marine plywood. The only downside is the voids, as Wayne stated as a prossible problem. If I can get a plywood with no voids in its veneers I will get it, but I don't believe that I can find here made in pine. Pine has more separate fibers, so is easy to chip, ergo we have voids. MDF, as I have noted is a very wood material with some limitations, moisture and poor mechanical to use with heavy drivers, but we can control this with some products and also we can use a plywood or a wood board for the front panel to fix the drivers, then we can do a sandwish to get an interior MDF layer (just a thought).
I will check also for the CNC labor, but maybe will be sufficient with a router.
Best regards

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Re: Pro 4 + seven midhorn and tweeter [message #51046 is a reply to message #51034]

Fri, 04 May 2007 05:39

dB
Messages: 234
Registered: May 2009

Master

Good.
(What country is yours, if you don't mind me asking?)
Do you mean they don't have too many types of wood there?
When you use (glue) different types they may warp, unless you make a sandwich.
Note: Also, I was thinking in good wood from old buildings (villas) like the planks from the stairs (and wide-plank flooring & windows, old and well dry) sometimes in exotic wood. Sometimes you may have a second resource beside new wood. They are now using old wine casks for speakers, recycled.

you can also read this interesting paper (in making guitars, I didn't read it yet): The Quest for Tone
http://www.mtdbass.com/articles/quest_for_tone.pdf

(pic. from http://uk.gizmodo.com/2006/07/11/pioneer_pure_malt_speakers.html)

RECYCLED Pure Malt Speakers

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Re: Pro 4 + seven midhorn and tweeter [message #51047 is a reply to message #51046]

Fri, 04 May 2007 19:10

beto1
Messages: 36
Registered: May 2009

Baron

Hi dB,
I'm in Chile, where are u?
Here we have a lot of wood, specially at South provinces. We export a lot of wood, well also very good red wine, btw. But I don't have good luck with plywood boards, because are made with just pine. Ihave inspect the phenolic plywoods at my work, and is a lot more homogenic that common plywood, but still have some voids.
I like a lot the building restoration work, recycling old extremely beatufull wood developed from old houses. Some architects use some portion of interior naked wood frames, puting away the wall cover (clay in some cases), getting visual continuity spaces. There are lot of (now very expensive, but 100 or more years ago, that was normal) old houses waiting with its treasures inside the walls and on stairs and others elements. I have work with recycled wood on modern clay houses using wood frame. Earth is a very good material.
Maybe some of this woods can work fine for speakers needs. The question is wich ones, because I know that some speakers builders talk about the enclosure as instruments that need the fine tuning of the aproppriate wood in the way that luthiers talk about fine artisanal instruments. I don't think that all beatifull wood can serve to our purpose because we need to avoid unwanted resonances, as far as I know. Thats why the no-at-all-aristocratic MDF was a good speaker material.
Maybe there are some fine examples of exotic wood that can stole the place of the proletarian MDF, but who knows if worth.
Best wishes

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