Woods with good tone?

[John Hollander]

I am looking at making some cellphone amplifiers out of wood for christmas They will be sort of like this http://www.youtube.com/watch?v=E2ylmYGkdeo. He recommends using cyperus and spruce , but I cant get them locally. What are some common woods that will give me a good tone for these "amplifiers"?

[scott vroom]

Cypress and Spruce are both very soft....sub-500 Janka, and 29 density. Poplar, redwood, fir, pine are similar hardness and density and are plentiful here in Nor Cal.

http://ejmas.com/tin/2009tin/tinart_goldstein_0904.html

[Halgeir Wold]

That thing works just by redirecting the soundwaves from the 'phone speaker and sending them out front. The block and front panel is way too thick to play any important role as a resonator, and if it did, it would generally do so for a few notes only, at their resonance frequency.... use any wood you like or are able to find, and you'll be just fine......

[Gene Takae]

That thing works just by redirecting the soundwaves from the 'phone speaker and sending them out front. The block and front panel is way too thick to play any important role as a resonator, and if it did, it would generally do so for a few notes only, at their resonance frequency.... use any wood you like or are able to find, and you'll be just fine......

Having experience making stringed instruments I have to agree with Halgeir. Go with a wood that looks good to you.

[John Coloccia]

It works by vibrating, not redirecting the sound waves. It's just as when you touch an electric guitar to the wall, or the dining room table, and it suddenly gets louder. I do suggest making out of a stiff, lightweight wood, and spruce would be an excellent choice. Perhaps spanish cedar would be a good choice as well. You may be able to find spruce 2x4s at the local construction supplier (not SPF...specifically spruce). White pine would probably be an excellent choice. Hemlock would be an excellent choice. Anything that's not too soft and not too dense. There's very little energy coming out of that speaker so you really don't want to muffle it or give it something that's difficult to get vibrating.

[John Hollander]

If I use a "stiff, lightweight wood" for the bulk of the speaker, will using a harder wood such as walnut for the face affect the speaker?

[John Coloccia]

I doubt it. I'm not sure how critical much of the design is, actually. After I posted, I went out and looked up some different designs. Some of them don't even have a channel for phone's speaker at all, so it just completely absorbs whatever is coming out of the speaker. Given the variations I've seen, I have to think that the design isn't optimal at all, and that a bit of fiddling around might give even more dramatic results. I may fool around with this during the winter. It's something I'd love to have for myself, but I can't leave well enough alone, of course

[Phil Barrett]

Yes. I would think a thin sounding board that the phone touches would be pretty effective. Much like the way stringed instruments work.

[william watts]

Halgeir and John have good ideas how these things could work, the vibrating wood theory or the redirecting sound theory. Should John decide to play around with them I think the redirecting sound theory may have an advantage. The channel for the sound from the iPhone to the vibrating panel could be designed as a horn speaker, greatly increasing efficiency. Have you seen an old hand crank phonograph with the big horn speaker, along that same principle. It would take some engineering , the dimensions are critical for maximum efficiency which is very high. Could be that from the throat to the mouth of the horn could just be open to the air.

[John Coloccia]

Halgeir and John have good ideas how these things could work, the vibrating wood theory or the redirecting sound theory. Should John decide to play around with them I think the redirecting sound theory may have an advantage. The channel for the sound from the iPhone to the vibrating panel could be designed as a horn speaker, greatly increasing efficiency. Have you seen an old hand crank phonograph with the big horn speaker, along that same principle. It would take some engineering , the dimensions are critical for maximum efficiency which is very high. Could be that from the throat to the mouth of the horn could just be open to the air.

I was thinking of that, actually. These particular designs are all wrong for doing amplification with a horn (really not amplification....more just increasing the efficiency of the driver by converting low amplitude, high pressure vibrations into large amplitude, low pressure vibrations), but a real horn design, possibly made by making a winding, internal channel in the wood, might yield some good results.

[Mel Fulks]

I think it was Vitruvious who wrote about large panels ,each tuned to a different pitch that would be placed in concert halls
to amplify sound. This thread also reminds me of an instrument I saw on TV show about an old firehouse. It was one of those spin around ratchet noise makers sometimes seen at new year parties. But much larger and used to wake up the crew when there was a fire. I guess the criterion was to use whatever wood they thought was the most irritating.