Question regarding gain table

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Joined: Wed Oct 28, 2020 4:12 pm

Question regarding gain table

Post by shaikath » Wed Mar 10, 2021 7:57 pm

I have some confusion regarding how gtmin and gtstep are used along with the level detector. If gtmax is not specified, is it assuming that gtmax is the peak level thats specified? What happens when a detected level is not exactly one of the gtmin+gtsteps? Does the gain specified for each entry in the gain table apply to a range of input levels (i.e. from gtmin to gtmin+gtstep)?

Posts: 9
Joined: Fri May 10, 2019 7:58 am

Re: Question regarding gain table

Post by hendrikkayser » Thu Mar 11, 2021 8:52 am

Hi Shaikath,
in case you're referring to the peaklevel values set in the transducers plugin: These values don't influence the gaintable itself. If the input level is below or above the range that the user has specified by the number of entries in gtdata in combination gtmin and gtstep, the gainable is extrapolated towards lower and higher levels.
For input levels that lay between exact gtmin+gstep values the given gaintable is interpolated, either linearly on linear amplification values or logarithmically according to the entry (no/yes) in the 'log_interp' parameter of the dc plugin. Note that the default is linear (log_interp=no), which may appear somewhat counterintuitive, as most people may by used to look at I/O curves on dB-scales.
You may want to check out our "dc_plot_io" Matlab/Octave tool to visualize the effects. It computes the output gain based on user-defined dc parameter values for gtmin, gtstep, gtdata and log_interp for any given input level value.

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