where is ref level on the realitine scale

For magnetic tape it is 0 VU referenced at 250nWb/m (nanowebers per meter) input
For phono cartdrige output (mV) it is at some reference velocity in cm/s (the actual number escapes me)
For speaker output (dBspl @ 1M) it is at 1mW/8ohms reference input
I hope this helps.