# Woodturning 600 pound Maple speaker cone



## laxin213 (Jan 25, 2013)

I saw this on youtube and had to share. Simply amazing. 

https://www.youtube.com/watch?v=W0Mod_92VZA&list=PLEDD7E5161BF39200


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## Bob in St. Louis (Feb 11, 2015)

Fantastic, thank you for posting this.
As an audio guy, and woodworker, I've been searching this forum for threads that combine two of my passions.
It's a shame the customer ruined the project, six THOUSAND dollars into it, by being cheap with the finish.
Thanks for the thread Laxin.

Bob


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## Bonanza35 (Jan 20, 2011)

Bob in St. Louis said:


> Fantastic, thank you for posting this. As an audio guy, and woodworker, I've been searching this forum for threads that combine two of my passions. It's a shame the customer ruined the project, six THOUSAND dollars into it, by being cheap with the finish. Thanks for the thread Laxin. Bob


What's the story with the finish? I didn't see any reference to it. 

My biggest concern is cracking. I have a hard time thinking it's not going to keep cracking over the next few months, as thick as it appears to be.


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## brizak79 (May 20, 2011)

Bonanza35 said:


> What's the story with the finish? I didn't see any reference to it.
> 
> My biggest concern is cracking. I have a hard time thinking it's not going to keep cracking over the next few months, as thick as it appears to be.


It was in the notes of the 2nd video: "A client paid for this project as part of his home entertainment system. Following turning, the client immersed the wood in a specially fabricated steel vacuum drum. Instead of using pure tung oil which he thought "too expensive", he decided to save money and used hardware-store spar varnish, a foul-smelling finish, in an attempt to make the wood translucent, similar to Cook Island / Norfolk Pine. It told him the maple would not become translucent but he persisted. The speaker came out with such chemical smell that it was ruined for use in any home. The person that paid for this project had more money than common sense. He paid me $6000 and gave me an opportunity to stretch my talents as a wood turner. My wife recorded the video, thank you to her. Part 1 of this video shows more technique."


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## bauerbach (Mar 25, 2012)

I dont quite get it... Ive used spar varnish... Im not saying its the best, but it works, and lots of people use it. 

Ive never had an issue with the odor though?


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## Steve Neul (Sep 2, 2011)

Watching the video it looked to me like the guy had a death wish. I don't think I could have stayed in the building with that chunk of wood turning. 

The spar varnish would work alright with the exception of it yellowing over time and it being less abrasion resistant. The smell of it would go away if allowed to completely dry which usually is a month.


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## Bob in St. Louis (Feb 11, 2015)

Steve Neul said:


> Watching the video it looked to me like the guy had a death wish. I don't think I could have stayed in the building with that chunk of wood turning. .


Agreed. The least I would have expected would be a broken wrist type injury. 
Yea, that was crazy. :blink:


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## Bob in St. Louis (Feb 11, 2015)

Ohh.....and another thing....
Was he only going to build one speaker?


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## bauerbach (Mar 25, 2012)

I would like to see a picture of such a speaker all done up.

Id also love to hear it.... I would think there would be more "science" behind it than just turning a big hunk of wood full of imperfections into an approx shape.

if thats the cone.... would this be a subwoofer? thats why only 1?


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## Bob in St. Louis (Feb 11, 2015)

Nope, subs would not have a cone. The "waveguide" starts at 1", since quite a few compression tweeters have 1" threaded "noses" 
to attach a waveguide to. 
Granted, most wave guides aren't quite this epic.

But there are a bunch of massive wooden waveguides on speakers, this isn't that uncommon.

A couple from Google;


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## bauerbach (Mar 25, 2012)

forgive my ignorance, you call it a wave guide? but the video called it a cone?

The cone produces the sound?

so are these actually producing the sound? or just directing (forming?) it?


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## Steve Neul (Sep 2, 2011)

I would hate to be a neighbor.


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## Bob in St. Louis (Feb 11, 2015)

The video is wrong in calling it a cone. The "cone" is the part of the speaker (technically called a "driver") that moves. This is the part that makes the sound by moving the air.

The wave guide, also called a "horn", doesn't move any air, but it does guide it and helps to tune the sound you hear. A true audiophile would scoff at a knob that changes the sound, like treble or bass knobs, but the size and shape of these will change the tone of the sound system. To the extend that guys will change these out until they find one that sounds right for their musical tastes, sounds good in their room, and has proper synergy with the other pieces of equipment in their system. 

Audio guys are as wacked out as wood working guys.

Hope that helps,
Bob - Woodworking audiophile.


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## woodnthings (Jan 24, 2009)

*my thoughts exactly!*

Speakers have cones as do ice cream shops AKA Baskin Robbins....

This is a speaker horn as stated. My theory is that it would have a resonant frequency possibly incompatible with the sound range of voice, music, or certain instruments making it a source of vibration or harmonics.:thumbdown: 

I think it was more of an "experiment" in turning a large stump, than any contribution to improved sound or acoustics, but I could be wrong. I used to be an "audiophile" in days long ago....


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## Ack (Mar 13, 2009)

Anybody else just think he was gonna make a spinning top?........


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## Bonanza35 (Jan 20, 2011)

brizak79 said:


> It was in the notes of the 2nd video: "A client paid for this project as part of his home entertainment system. Following turning, the client immersed the wood in a specially fabricated steel vacuum drum. Instead of using pure tung oil which he thought "too expensive", he decided to save money and used hardware-store spar varnish, a foul-smelling finish, in an attempt to make the wood translucent, similar to Cook Island / Norfolk Pine. It told him the maple would not become translucent but he persisted. The speaker came out with such chemical smell that it was ruined for use in any home. The person that paid for this project had more money than common sense. He paid me $6000 and gave me an opportunity to stretch my talents as a wood turner. My wife recorded the video, thank you to her. Part 1 of this video shows more technique."


Thanks for clearing that up. It was a cool project and $6000 commissions don't come around too often for turners! Congrats! What ever happened to it? Did the odor really persist? Did the cracks develop more or did they stabilize?


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## bauerbach (Mar 25, 2012)

Im a little dubious if the guy that made it isnt being a bit... salty with his after story.

Perhaps the guy that commissioned it didnt care to spend money on tung oil because... it didnt work? maybe he hooked it to a speaker and found that the experiment failed? it didnt sound good, he didnt like the "rough" look of it? Saw the cracks and realized it wouldnt last... 

I did wince at the idea of that thing turning on that lathe, the gloves, the general danger of it all. I found it curious that he had it spinning in the hoist straps later on... I watched without sound and did skip through it, maybe he addressed that.

He clearly did not center the mount when he flipped the cone on the lathe, which means the walls would not be equal thickness. does that matter to the product? I dont know, it upsets my OCD though.

For $6000, the product did not look polished. An interesting experiment, and perhaps the owner had a pie in the sky idea to begin with, but I think the guy bit off more than he could chew. Probably a better job for a CNC lathe or something...


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## Bill Boehme (Feb 9, 2014)

bauerbach said:


> .... I did wince at the idea of that thing turning on that lathe, the gloves, the general danger of it all. I found it curious that he had it spinning in the hoist straps later on... I watched without sound and did skip through it, maybe he addressed that.
> 
> He clearly did not center the mount when he flipped the cone on the lathe, which means the walls would not be equal thickness. does that matter to the product? I dont know, it upsets my OCD though ...


I got the impression that the customer had his own misguided ideas on finishing it and that perhaps the woodturner had told him his recommendation.

The turning process isn't as dangerous as it may appear to you, but it certainly isn't a job for somebody who does not have a lot of experience with turning very large pieces. The biggest problem is the very slow speed and interrupted cutting which made the initial work very slow going. Maybe if somebody waved $6K under my nose ... that would be about 80% of what I paid for my lathe. The fact that I would have recognized that the project was going to be DOA would have been enough to decline the job.

When he turns it around to do the hollowing, it always will be necessary to do at least some turning on the exterior to true thing up because it is next to impossible especially on really heavy pieces to insure that the axis of rotation hasn't shifted.

Without going back to view it again, my recollection was that he was using a steady rest during the hollowing process. I don't recall it being supported in a sling as well.


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## bauerbach (Mar 25, 2012)

I think the sling went on before he flipped it. I think he started hollowing it out from that side first, a doughnut cavity as it was.


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## Bonanza35 (Jan 20, 2011)

I'm not sure how many have noticed that the turner in the video is on this forum and has posted on this thread. I bet he would appreciate questions instead of criticism.


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## Bill Boehme (Feb 9, 2014)

woodnthings said:


> Speakers have cones as do ice cream shops AKA Baskin Robbins....
> 
> This is a speaker horn as stated. My theory is that it would have a resonant frequency possibly incompatible with the sound range of voice, music, or certain instruments making it a source of vibration or harmonics.:thumbdown:
> 
> I think it was more of an "experiment" in turning a large stump, than any contribution to improved sound or acoustics, but I could be wrong. I used to be an "audiophile" in days long ago....


 For the benefit of others who aren't audiophiles and familiar with audio pioneer Paul Klipsch and the revolutionary changes that he brought to the industry with his elliptical horn design, here are a couple brief Wikipedia articles:


The first is a brief *biographical sketch* about the man.
The second is about his company and about the *Klipschorn *itself which is a folded elliptical horn.
Unlike a simple horn design or any other speaker enclosure such as ducted port, bass reflex, etc which all have pronounced resonances, the elliptical horn has a number of smaller resonance peaks, but despite that, they still add a coloration to the sound that clearly says, "elliptical horn".

The design of the turned wooden horn doesn't appear to be truly elliptical. Also, having holes and bark inclusions might look cool, but I doubt that it is good for the sound quality.


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