2 minute recording time

[oceanlinerfanatic]

What would be the longest amount of time you can get from recording on a 2 minute cylinder. I know these generally play at 120 rpm but what is the lowest speed you can use to record on without significant sound distortion. I have seen several 2 minute recordings played at 90rpm to get around 3 and a half minutes of recording time. Has anyone experimented with this?

[recordmaker]

The language lesson cylinders from ICS via Edison 2min records are 90 RPM as standard and thus give about 4.5min at moderate quality for speech and using listening tubes. The reduction in volume and quality due to the lower speed for particularly for music is added to with the general lack of steady playback at the lower speeds as phonograph mandrels have little flywheel action compared with disc turntables.
I did run some experiments for a project down to speeds as low as 30 RPM, but only really to prove that it you could not just get more time by lowering the speed as even speech becomes difficult to listen too.
At 160 RPM the high frequencies recorded and reproduced may extend to 5 KHz on a cylinder cut and at 80 RPM this will be reduced to half 2.5 KHz which will be muffled and at 40 RPM this goes to 1.25 KHZ which makes speech very indistinct. At some point the tops of the wave are bridged by the stylus rather than followed and reproduced as they are closer together due tot the reduced speed.

[oceanlinerfanatic]

The language lesson cylinders from ICS via Edison 2min records are 90 RPM as standard and thus give about 4.5min at moderate quality for speech and using listening tubes. The reduction in volume and quality due to the lower speed for particularly for music is added to with the general lack of steady playback at the lower speeds as phonograph mandrels have little flywheel action compared with disc turntables.
I did run some experiments for a project down to speeds as low as 30 RPM, but only really to prove that it you could not just get more time by lowering the speed as even speech becomes difficult to listen too.
At 160 RPM the high frequencies recorded and reproduced may extend to 5 KHz on a cylinder cut and at 80 RPM this will be reduced to half 2.5 KHz which will be muffled and at 40 RPM this goes to 1.25 KHZ which makes speech very indistinct. At some point the tops of the wave are bridged by the stylus rather than followed and reproduced as they are closer together due tot the reduced speed.

Thank you very much for this. It is very helpful

[Inigo]

Knowing the size of the stylus you are using is vital, as the dimension of stylus footprint parallel to the groove dictates the minimum trackable wavelength, related to the speed of the cylinder too. This can be calculated to make the stylus fit in the groove crests and valleys, and not jumping over... That's also what makes that larger cylinder diameters allow higher sound fidelity at the same speed (the concert, etc)