Old school boom box input equivalent using SoX

I used to have a cassette tape/radio unit (boom box format) device.

I used to use this to record mix tapes from my dual turntable and mixer setup. The resulting tapes were – for me – ideal for playing in the car because

1. The tape itself ran a tad slow which – when you played back on another deck speeded up the music by roughly the same amount as was used in the classic era of music radio in the USA – which I loved (yeah, I know philistine and all that).

2. The AGC in the blaster input would almost infinitely expand sounds all the way down to rumble or surface noise if I let a record run out, but would also tame loud sounds nicely. In short it absoluteley murdered the dynamic range – but for car listening I found this was just excellent (again, for me, I know others will blench at this 😎 ).

So, to my question regarding SoX. I have found out that speed 1.02 gets me the speed up I am trying to reproduce. I also found a set of dynamics that reproduce the limit function of classic FM radio – but I also want to reproduce the infinite expander that I once had on the cassette deck.

I did manage to get close to it using Cool Edit 2000 compander, but that’s long ago stopped working and the Audacity compander doesn’t (IMO) do as well. I can’t pretend to understand the way that Sox dynamics work, so I wondered if anyone could post be a command that might get me there? If it would help, I can post an example of a digitised mix tape from that era (file of about 80MB) on my site so you can hear the music junction dynamics I am trying to reproduce.