> this has many benefits, the main one being that chaining gain/attenuation in a system is just a case of adding the db values together. 'We're loosing 4db in this cable, and the gain through this amp is 6db, so the output is 2db hotter than the input'.

I'm not a sound engineer, so to check my understanding: would this not be the case for any other scale indicator?

If you have a cable that loses 4m and you're sending 6m into it, you'd not get 2m out?

(The m being milli here, as in millivolts or whatever unit would be useful here — leaving it unspecified to keep the comparison to dB as close as possible)