On Wed, Oct 16, 2024 at 02:43:12PM +0100, Will Godfrey wrote: > There are two other factors I know of that might be relevant. > > At high tape speeds there is a drop in the replay amplitude of lower > frequencies. I believe that is due to the wavelength on the tape relative to > the width of head pole pieces. I don't know if that affects both record and > playback or just one or the other.
There are two reasons for this. 1. The NAB standard (used mainly in the USA and by Nagra at 30 IPS speed) uses LF pre-emphasis. The actual filter used is always an approximation of the one specified by the standard, as that one can't exist in real life - it would require infinite gain at DC. The actual filter used can lead to some loss at very low frequencies. 2. There is an affect depending on the physical size of the playback head relative to wavelenght. This may results in an irregular LF response. Both effects are perfectly linear, if they matter all you need to emulate them is some EQ. > The background noise spectrum and amplitude changes with different tape > speeds. > I think that's related to the grain size of the magnetic particles on the > tape. The noise spectrum changes are mainly the result of the playback EQ depending on tape speed. Again, if the noise contributes to the 'quality' of analog tape, all you need is to add it. Ciao, -- FA _______________________________________________ Linux-audio-dev mailing list -- linux-audio-dev@lists.linuxaudio.org To unsubscribe send an email to linux-audio-dev-le...@lists.linuxaudio.org
