TOPIC:

The miniDSP manual (v 1.6) states that signal levels have to be below 0 (zero) dBFS on the meter display to prevent saturation and distortion. I measured my input signal level (400Hz sine) and, as expected, saturation starts at levels higher than 900 mVrms, input jumper on 0.9 Vrms. The input meter display of the '4 way crossover adv' plug-in is showing -6 dBFS at this level. So we better keeps signal levels below -6dBFS, right?.

When I decrease the input signal in steps of -6 dBVrms the input meters, and the output meters as well, are taking steps of -12 dBFS. (?)

The same behaviour of the meters is found when the miniDSP is stacked with a miniDIGI and digital signal is applied. A 0 dB digital signal (400Hz sine) shows on the meters as -6 dBFS, obviously this is the maximum signal level. Decreasing input signal with steps of -6 dB again is seen on the meters as steps of -12 dBFS.

This looks to me like a scaling error in the software or I am missing the concept of the plug-in's dB scale?

I'm noticing the same thing.

Dear All,

after a bit of investigation, it indeed seems like there is something not normal on the meter refresh.
Thanks for letting us know. Seems like a bug that we'll solve in the upcoming version.

Update to follow when we release a new plug-in,

Devteam

Maybe you can then implement my suggestion for a sticky peak indicator on the meters?
Since you are in that part of the software and making changes anyway.

+1

Indeed a good idea for a next improvement Eric. We'll have a look at what can be done.

Hello,

Have you not found out how to correct this yet?
I can not set the final gain structure before I know the correct
headroom I have on different inputs and outputs.
Does the THD stay low all the way up to 0 dB on input and output?
How are 16bit to 20bit digital input signals mapped by the ASRC, is the most significant bit always in the same position in the 24 bit output?

Hello,

We indeed have a solution for the RMS meter but are just packing up a couple of features whenever doing a release (typical to any software dev). In the mean time, not sure why you can't set up your system, but if you apply say 6-12dB headroom on the current meter reading, you will be fine.

The SRC provides a simple word length reduction mechanism for reducing 24-bit audio data to 20-, 18-, or 16-bit
output word lengths. Word length reduction is performed utilizing triangular probability density function (or TPDF)
dither. You can read online more if you want to understand how to works.

hope this helps,

DevTeam