Phonovision not digital?

[DrZarkov]

Very interesting forum! Have you seen this one: http://www.floka.com/lofi/edison/edison_cut.html? I've copied the direct link. After the beer can phonograph another interesting thing from Switzerland. He uses simple PVC drainage pipes, with success. Not perfect, but it works!

[ac7zl]

Steve:

What do you do your drawings with?

Pete
AC7ZL

Quoting from Wiki:- these were about 4 inches (10 cm) long, 2¼ inches in diameter, and played about two minutes of music or other sound.

What they don't mention is the rotational speed which would allow one to work out the track pitch.

OK, so let's take those dimensions as a starter. 2¼" = 57.15mm, a circumfrence of 180mm. Given a rough estimate of 500mm/sec as per previous posts = 2.77rev/sec, 167RPM. So to store 2 minutes of sound there needs to be about 333 turns on the cylinder.

The length of the cylinder is 4", or 100mm, but there surely must have been some 'land' at each end which was unusable, akin to the lead-in and lead-out grooves on flat records. So let's say that there is 80mm available. this works out to be a track pitch of 0.24mm. Quite fine really.

Attached is a sketch which shows a cylinder driven at one eigth of the disc/drum rotational speed of 750RPM, i.e. 93.75RPM. From this is derived a lead-screw with the pick-up device driven at a ratio of 4:1, 23.4 RPM. Using a standard M6 screwthread comes out to be 23.4mm/min, so within 80mm we could have over three minutes of recording time.

Having said that I just had a look at the only LP record that I have in this house. It's radial playing dimension is about 89mm, on the assumtion that it plays for 20 minutes that's a track pitch of 0.134mm, quite amazing really. This is an average, the pitch was dynamically altered between loud and softer passages.

The sketch is just a concept, it would need to rearraged for easy changing of the cylinder.

It really is over to the mechanical guys here...

Steve A.

[Steve Anderson]

Steve:

What do you do your drawings with?

Pete
AC7ZL

AutoCad 2007 from AutoDesk, but it will set you back at least US$3500, that was the last time I checked. It's the default drawing package in most industries, especially architechture where it renders people, trees and other objects with amazing accuracy. You can change the position of the sun, modify the sky conditions to create the mood you wish.

The drawings I do just barely scratch the surface of its capabilities. The attached is a very simple example of what it can do. It's just a simple rendered isometric drawing, not 3D which AutoCad can do brilliantly in the hands of a good author.

I saw a demo a few years back where the whole interior of the building had been fitted out, it was close to photographic quality, and although the building hadn't yet been even started, I could go to the bathroom and believe that it was real.

Steve A.[/u]

[gary]

My apologies if this link has been given before (a search didn't find it)...

http://blog.modernmechanix.com/2007/06/ ... #more-2623

[Telehor]

Why using wax cylinders, this is easy to find material....

sites: http://www.christerhamp.se/phono/index.html

http://www.floka.com/