hi,

i have a mk2b unit and need to know what volume no. or voltage the audio output signal starts clipping at? i dont have access to a scope any more so if someone can put their unit on a scope or already knows please let me know.

thanks,

chris.

i have a mk2b unit and need to know what volume no. or voltage the audio output signal starts clipping at? i dont have access to a scope any more so if someone can put their unit on a scope or already knows please let me know.

I'm not sure what you're asking here: the car-player does exactly what it says it's doing. If the EQ is flat then the car-player will clip an FSD input signal when the volume is over 0db. FSD on the car (docking connector) outputs is 4V, which is the standard line-level of car audio components. FSD on the home (RCA/phono) outputs is 1.75V, which is the standard line-level of all other audio components.

Peter

Edit: I thought it was 1.75V, but everywhere else says 1V, so I could be wrong about that bit.

sorry, ill try to be more clear.

will the audio signal only ever go into clipping if you exceed 0db on the output volume?

reason i was asking about voltages is i know with my amps (fusion monoblocks) the audio signal will clip as soon as the output voltage reaches 60v (so i dont need to wire them to a scope to see if they are clipping, i just set the output to 59v).

i was therefore assuming that the head unit audio output would work in the same way - as the volume rises so too would the voltage of the signal. i didnt realise it was a constant 4v.

will the audio signal only ever go into clipping if you exceed 0db on the output volume?

Yes, if the EQ is flat. If you boost certain frequencies in the EQ, the audio signal will clip with FSD signals of that frequency even if the volume is slightly below 0db. (That's why the usual recommendation is to EQ by attenuating the frequencies there's too much of, rather than boosting the frequencies there's too little of.)

i was therefore assuming that the head unit audio output would work in the same way - as the volume rises so too would the voltage of the signal. i didnt realise it was a constant 4v.

The voltage does rise with the volume. The output stage of a car-player will clip if asked to go beyond 4V. Setting the volume to 0db (with the EQ flat) and feeding it a FSD input asks it to go up to exactly 4V. Setting the volume below 0db will mean it's never asked to go above a certain lower value. Setting the volume above 0db will mean asking it to exceed 4V on FSD signals (it'll refuse, and clip), but not on quieter signals.

Peter

nice one, thank you.

i run the eq flat on the head unit, all the signal processing gets done by separate units between that and the amps.

ta for your help.

Yup, more details about the EQ can be found here if you're interested. And by the way, there's a configuration feature that will let you "cap" the volume at 0db so that you don't accidentally go into clipping range.

In practice, if you're using the player's EQ as "all cuts", and playing normal music which rarely makes a certain specific frequency hit maximum deflection for long enough for the clip to be noticeable, it's possible to sometimes exceed 0db on the volume control without noticeably clipping. But it depends on the music and how you've got the EQ set up.