Discussion on what materials to build speakers out of

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planet10 said:


2 VI diyFests ago we built otherwie identical MDF & plywood bipolar ML-TLs for the FR125. Everyone could hear the difference.

dave


A difference? As in one sounded better than the other, or just different? Was this a blind test, as in were the construction materials exposed for everyone to see? What was the purpose of this test in the first place - to demonstrate the sonic inferiority of MDF? Sounds like a ringer to me.
 
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planet10 said:


I'd use 1/2" HDF (medite) over 3/4" HDF any day (i used to build everything out of 1/2" medite until i started listening to boxes in BB)

dave

Sounds like you prefer the way baltic birch boxes sound. Hearing is subjective. What one person likes, another dislikes. I hate country music. Some people love country music. Although I personally believe it, is my taste in music better than theirs? I like speakers that have clean low reaching bass and sparkling highs. Some others prefer midrange definition. Would the speaker that meets my criteria be better than the one that meets theirs?
I will admit that I have never heard a speaker built from baltic birch, maybe I would prefer it also.
 
frugal-phile™
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I like boxes that don't add sound of their own.

The MDF vrs Ply comparidson had the MDF box smooshing over a whole lot of the low level detail in the music.

In other words the BB boxes had greater downward dynamic range. There was more information. They imaged better.

Nothing to do with taste ... unless you like your music blenderized (but that is what elevators are for)

dave
 
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planet10 said:
I like boxes that don't add sound of their own.

The MDF vrs Ply comparidson had the MDF box smooshing over a whole lot of the low level detail in the music.

In other words the BB boxes had greater downward dynamic range. There was more information. They imaged better.

Nothing to do with taste ... unless you like your music blenderized (but that is what elevators are for)

Maybe there was a difference between the drivers - no two are identical. Maybe hasty box construction came into play? Your test conditions are flawed. The personal bias of the listeners when they know what they are listening to is the biggest flaw.
In my view, box construcion methods are a bigger source of colouration than material.
Same design, same drivers and materials, built by two different constructors can sound different. One better than the other? It's in the ears of the listener.
 
Maybe there was a difference between the drivers - no two are identical. Maybe hasty box construction came into play? Your test conditions are flawed. The personal bias of the listeners when they know what they are listening to is the biggest flaw.

Hi MJL21193!
I built, compaired identical boxes with the same drivers, using a false baffles for quick changes. I prefer in order.

1. Plywood
2. Solid wood
3. Chip board
4. MDF

To be honest, here comes the feeling you get of the solid wood in play. I would put real wood first if emotions were involved. (Grew up in the forest)

To be frank, I think you have to make your own conclusion,because this exchange will not lead anywhere!
:) :)

Cheers
Peter
 
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peterbrorsson said:

I built, compaired identical boxes with the same drivers, using a false baffles for quick changes. I prefer in order.

1. Plywood
2. Solid wood
3. Chip board
4. MDF

To be honest, here comes the feeling you get of the solid wood in play. I would put real wood first if emotions were involved. (Grew up in the forest)

To be frank, I think you have to make your own conclusion,because this exchange will not lead anywhere!
:) :)

Cheers
Peter

Peter!! Nice to hear from you. All of the above materials resonate at different frequencies, therefore they will colour the sound differently. Modern speaker building methods dictate that the box should not resonate - great lenghts are gone to to dampen box vibrations.
What I am saying is that as long as you have done all that you can to silence the box, it doesn't make a difference what it's made from.
Like I said earlier, all materials resonate. How much is up to the builder.
I also grew up in a forest, and I love wood, and as a carpenter I get to work with it in it's many forms for a living. I know most of it's qualities, stenghts and weaknesses.
As far as having made my own conclusion, yes I have, but I can listen to reason, if it's presented to me. Like I said earlier, I have never listened to aspeaker made from baltic brch plywood. Maybe I would see the light. :)
Anyhow, I joined this forum to talk about these issues. I'm not looking for any resolution, just a good lively talk. It's healthy to hear a different opinion once in a while, is it not?

Have fun
 
Not everyone agrees about totally dead boxes. On the principle that it's almost impossibe to deaden a practical cabinet, I would suggest resonance control, rather than erradication, is what is generally aimed for. The confusion of the two is where many of the problems lurk.

Interesting debate though this is, might I tentatively suggest that it's best to agree to disagree and leave it there? We seem to have gone somewhat off the subject of the original thread, & we should probably try to get back on-topic re the Calhouns, or the principle of their operation anyway. Sorry Cal! We can always have a separate thread on materials -there've been quite a few in the past.

Re a separate thread -to start you off; here's two comments for it -but let's not clutter up Cal's thread any more here, save it for elsewhere.

1) A favourite of Terry Cain's for large side panels for horns etc., using FR drivers was a 1in thick lamination: an internal 1/2in core of particleboard with 1/4in of birch ply on either side, which he laid up himself. Most of his original DIY cabinets used this for the side-panels.

2) You want something with resonances pushed well out of the cabinet's operational passband? OK. Try something like 10g steel. GM suggests cold-rolled would be best if memeory serves.

Best
Scott
 
What I am saying is that as long as you have done all that you can to silence the box, it doesn't make a difference what it's made from.

Scott: OT is what it is. I would like add one more thing. Then it's finished from my side.

MJL21193: The comment above I've heard before from someone else together with a rude remark!!
My question is if one can solve a problem as easy as possible, why complicate it by using something that one has to reinforce to make it work?

In my occupation, everything has to be kept as simple as possible to work in production. Any compromise that needs additionally components makes it more difficult to use.
I believe that simple solutions are the best!

Cheers

Peter
 
I joined this forum to talk about these issues. I'm not looking for any resolution, just a good lively talk. It's healthy to hear a different opinion once in a while, is it not?

Hi MJL21193! (Do you have a name, feels like speaking to computor)

I agree about what you wrote, but has to draw a limit somewhere, when it's not leading anywhere!:) :)

Have fun as you wrote!

Cheers
Peter
 
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MJL21193 said:
Maybe hasty box construction came into play? Your test conditions are flawed. The personal bias of the listeners when they know what they are listening to is the biggest flaw.

Hasty construction was not an issue. Except for Chris & I no one knew which box was which. Guesses as to which was which seemed to run 50/50. The differences were not the kinds -- or magnitude -- you get from 8 well matched drivers.

dave
 
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Scottmoose said:
Not everyone agrees about totally dead boxes. On the principle that it's almost impossibe to deaden a practical cabinet, I would suggest resonance control, rather than erradication, is what is generally aimed for.

Speaker building philosophies tend to run into 3 camps, damp the h out of the box, push inevitable box resonances up out of bans or at least high enuff that they don't get excited, and the box is a musical instrument camp. The last is an artform and very very difficult to get right or get consistent so lets set that one aside.

I was very firmly moved from the 1st camp to the 2nd camp when i had the opportunity to sit down with and talk to John Greenbank & his crew from Tangent in the late 70s. Build the box stiff, keep panels "small" and push the resonances high so they don't get excited. The Tangent speakers punched way above their price with drivers i was well familiar with. I have been refining that technique since (closing in on 30 years).

On the face of it the 1st camp makes sense, but what happens is that not all the energy is damped. The heavily damped panels have low resonance frequency, low Q and are easily excited. One tries to damp that energy, but some of it is stored and reradiated at a low level, and with a wide bandwidth. Sort of like trying to play basketball on a court covered in a thin layer of molasses, or playing hockey with a thin layer of water... all the subtle moves are damped out and you loose your finesse & agility.

As Peter pointed out there are also practical considerations too... less material, and lighter weight mean less cost, and lower shipping costs which roughly translates to less energy use (which if you extrapolate far enuff and loosly enuff you are helping to save the planet :))

dave
 
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planet10 said:


Speaker building philosophies tend to run into 3 camps, damp the h out of the box, push inevitable box resonances up out of bans or at least high enuff that they don't get excited, and the box is a musical instrument camp. The last is an artform and very very difficult to get right or get consistent so lets set that one aside.

On the face of it the 1st camp makes sense, but what happens is that not all the energy is damped. The heavily damped panels have low resonance frequency, low Q and are easily excited. One tries to damp that energy, but some of it is stored and reradiated at a low level, and with a wide bandwidth. Sort of like trying to play basketball on a court covered in a thin layer of molasses, or playing hockey with a thin layer of water... all the subtle moves are damped out and you loose your finesse & agility.

Well there you have it. I am deeply entrenched in this first camp; it gives the most predictable results. The low level radiation you refer to Dave is below the noise floor, easily overpowered. I wouldn't compare it to playing hockey with water on the ice, but rather an opposing fan heckling the players on the ice from the parking lot.
I would be willing to experiment in both of the other camps though. Naturally not with solid wood though. I have in the past considered building my own plywood - the only way to ensure consistancy and absense of voids.

scottmoose: Steel? Like what some bels are made from? That has a nice RING to it! ;)
 
As Peter pointed out there are also practical considerations too... less material, and lighter weight mean less cost, and lower shipping costs which roughly translates to less energy use (which if you extrapolate far enuff and loosly enuff you are helping to save the planet )

Dave, are you using tubes or class A amps?;) 350W idle is not what I call environment friendly:):)

I've got an wood offer for my Sonido BIB's this week that mounted the good of 500 Euro's. This is 25 mm three layer with middle section cross grain and A and B sections 6,5 mm. This is supposed to be better than plywood according to some wood working people I know.

I thought I should give it a shot but at 150 Euro/sqm.....
Back to 20 mm Birch plywood which will be little more than half the price of above.

Cheers
Peter
 
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peterbrorsson said:
Dave, are you using tubes or class A amps?;) 350W idle is not what I call environment friendly:):)

Class A, but low power. Even at only 20% efficiency, something like 40 W dissipation for a stereo amp -- and in the winter the extra burn helps (in a very minor way) to keep the house warm. And we keep trying new amps -- i have a 10W Class D under construction for the day when we find something that sounds as facinating.

We have replaced all the incandescent lights with compact flouescent to help make up. And the amps have a high recycle content, helping keep the landfill situation.

dave
 
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