To me, Koa is even brighter than Mahogany. My Ukes are made of Koa.
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Pros and cons of solid wood (mahogany) for a woofer-only enclosure.
- Thread starter terpodion
- Start date
desertrat748
Super Member
yes and I’m still sure they braced it well even though they have only ? Small 5 or 6 inch low end drivers?
They were measuring the elastic modulus and Q of various materials and doing it scientifically. Not research that I would dismiss as having "no correlation". Of course a box will behave differently to a plank - that isn't in dispute - but it doesn't negate the usefulness of the research. I'm sure the people conducting the research weren't idiots.
BTW, the BBC wanted to produce loudspeakers as working tools and wanted them to be cost effective. I'm sure they were aware that enclosures could be made that were more inert but they were looking for practical solutions which didn't cost a fortune to produce. The engineers working on the project would probably be amazed if they could see the prices of some of the loudspeakers on the market today.
NH-MAN
Addicted Member
Not saying they are not intelligent but the test would only be useful for someone using that strip of wood in that size and that thickness with that moisture content ect et. Attach it to something, change the thickness and width and everything changes. Just hold the free edges of the piece of wood during testing everything changes. Only useful for what it was.
desertrat748
Super Member
That test had a summary and it clearly stated that it wasn’t a good idea to use timber for speaker design.
Again the OP asked what pros or cons were for mahogany planks. Beautiful wood for a bass guitar but not a great idea for speakers. Imagine going through a lot of hard work and everything else only to find out that it was impossible to get a balanced sound out of it.
Chasing your tail around and around trying to figure out what is causing a spike in the upper bass or midrange? Not without a lot of testing and great design that would be eliminated if proper material was chosen first.
NH-MAN
Addicted Member
In conclusion then I am done. "All" of our speaker cabinets have some resonance frequency at some range.
Barring a poorly built box I entertain you all to put your ears on the outside of your Enclosures like you are listening to a seashell while music is playing and try to figure out at what point your enclosure is adding some resonance and spoiling your music, somewhere theoretically it will. I'll just enjoy mine.
Barring a poorly built box I entertain you all to put your ears on the outside of your Enclosures like you are listening to a seashell while music is playing and try to figure out at what point your enclosure is adding some resonance and spoiling your music, somewhere theoretically it will. I'll just enjoy mine.
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"The test" was to measure the basic properties of a range of materials for comparison, not to measure the properties of any particular strip of material. Furthermore, the research goes on to test complete loudspeaker enclosures for sound transmission through the walls of the enclosure and study the effects of various types of damping material.
Anyway, for anyone less dismissive of the research and who is interested to study the BBC's findings, the complete document is available to download free of charge.
There's actually a simpler, though less scientifically rigorous, way to test loudspeaker enclosures that any serious DIYer can experiment with. Basically, you just have to play sweepable test tones through the speaker and sprinkle sand or salt onto the panels (oriented to be horizontal) and observe the patterns formed by the sand at different frequencies. It might help in determining how/where best to brace and/or damp an enclosure.
Personally I think if the OP made speakers out of his mahogany they would be fine, but I'd much rather see him use MDF or plywood and make a musical instrument with the mahogany.
Mike Stehr
Poverty Audio
This old beast is at least 60 years old. I have a pair, and they are made from solid 3/4" Mahogany.
The cabinets were stained walnut with some sort of polyurethane over that. The outside of the cabinets are sealed and probably one reason why they are still around.
The motorboards however were not sealed, and they did warp. But they had cut-outs for a 15" driver, and the cabinets are more in spec for 12" drivers.
I went ahead and used 3/4" Baltic birch for motorboards, and fashioned them for 12" drivers.
My guess is back in the day, furniture quality with speakers was just as important as sound quality.
Attachments
When I built my DIY subs, a friend who helped me, worked as a summer intern at JBL. He said 3/4-inch MDF was the way to go, for overall strength, lack of bass tonal signature, and low inherit resonance frequency. Built correctly, it needed the least amount of internal bracing --- which he said was good for good bass response. To reduce standing and internal interference waves. And keep internal volume as high as possible. If I remember correctly. It's been a long, long time.
I hand-wound the 20mH chokes with 100mfd caps = about 115Hz crossover (6dB/octave). I used JBL 136A 15-inch speakers --- which match those in the L300, at the time.
desertrat748
Super Member
When I built my DIY subs, a friend who helped me, worked as a summer intern at JBL. He said 3/4-inch MDF was the way to go, for overall strength, lack of bass tonal signature, and low inherit resonance frequency. Built correctly, it needed the least amount of internal bracing --- which he said was good for good bass response. To reduce standing and internal interference waves. And keep internal volume as high as possible. If I remember correctly. It's been a long, long time.
I hand-wound the 20mH chokes with 100mfd caps = about 115Hz crossover (6dB/octave). I used JBL 136A 15-inch speakers --- which match those in the L300, at the time.
I couldn’t see gluing a bunch of mahogany boards together, running them through a planner and then building a box with them.
MDF or birch plywood so much easier and better.
I’m building my daughter a table and bench today. Birch ply is excellent and strong. I would use it for speakers.
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You'd prolly have to finger-joint those mahogany boards together. To get the best long-lasting tone or sound, out of them. Like they do with quality guitar amp cabinets. I would think? 
https://300guitars.com/spotlight/spotlight-larry-rodgers-rodgers-amplifiers/
Oh BTW... I remember my friend said to place the speaker off-center in those DIY subs. This helped with reducing internal standing and interference waves.
https://300guitars.com/spotlight/spotlight-larry-rodgers-rodgers-amplifiers/
Oh BTW... I remember my friend said to place the speaker off-center in those DIY subs. This helped with reducing internal standing and interference waves.
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Andre Garcia
“WITHOUT MUSIC, LIFE WOULD BE A MISTAKE”
Interesting if someone have a recording using wood speakers, to notice the difference.
AG.
AG.
terpodion
Active Member
Bringing organs back into the discussion; pipes are one thing, with the various materials they are made from: Nearly pure lead, plain metal (40% tin and under, the rest lead and hardeners) spotted metal (70% tin and over) pure tin and zinc for big metal pipes, pine, poplar, oak and occasionally mahogany - but there is another important part of pipe organs where the acoustic properties of the materials matter quite a bit: the "expression box" or "swell box". This is simply a type of case, not unlike a speaker enclosure, with large shutters on one or more sides. Pipes are inside it and the shutters are attached to a pedal that opens and closes them to regulate the volume of sound. These enclosures were traditionally built from solid wood (plywood and MDF hadn't been invented) but in the early 20th century an English Telephone engineer with a musical background began building organs and had very radical ideas. He built them more like acoustic synthesizers. Everything was extreme, very loud pipes on high wind pressure, pencil thin string pipes, huge scaled foundation and flute pipes, trumpet style pipes as loud as truck horns. Guess what he made his expression boxes out of. Concrete. The shutters were faced with lead sheets and each weighed 700 Lbs. When the shutters were closed, even the loudest stops became soft enough to accompany the singing of a small child.
Nobody builds them that way anymore. But I do see modern builders (myself included) using MDF and Baltic birch. The problem with MDF is that if it gets wet, it is ruined. It's a sponge. Church roofs are rather notorious for leaking.
Nobody builds them that way anymore. But I do see modern builders (myself included) using MDF and Baltic birch. The problem with MDF is that if it gets wet, it is ruined. It's a sponge. Church roofs are rather notorious for leaking.
Well terpodian , what did you end up doing ? I can,t get over all the comments re what a waste to use the wood to build speakers !, " ....something like a nice table ..." was included in a post . A table ?? , screw the table , tables are thrown out on gumtree over here weekly , bloody expensive ones too , like the solid 25 mm thick rosewood extension table with 4 extension leaves and 14 chairs advertised a few months ago . You could have built 2 pair of 3 ways and had enough fire wood out of the chairs to last you a month ! Anyway l digress , if it's not too late to put up a suggestion ? I would rotate an existing pair to the office and build a TOTL pair of O-Bs with the mahogany with something like A E bass and mid drivers . The mahogany could be laminated to 40 mm thick kitchen counter top for damping and rigidity and to keep within reasonable costs . That could really show off this lovely timber and have a unique pair of speakers , just an idea . 