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lsp-plugins / lsp-plugins

Linux Studio Plugins Project
https://lsp-plug.in/
GNU Lesser General Public License v3.0
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Spectrum analyzer gain values. #434

Open sergionexus opened 6 days ago

sergionexus commented 6 days ago

When using LSP Spectrum analyzer, gain values of the different frequencies are not the same as the values showed by other metering plugins like T-Racks Metering for example.

sadko4u commented 6 days ago

Hello! And?

sergionexus commented 6 days ago

Hello! And?

And I can't trust it if all the other metering plugins give other values. I don't know if it's a bug, but the fact it's that this plugin gives wrong values.

sadko4u commented 6 days ago

The gain value is a relative value and has a sense when you compare it to some other gain value. Have you compared the results given by other plugins respective to yours reference one?

sergionexus commented 6 days ago

The gain value is a relative value and has a sense when you compare it to some other gain value. Have you compared the results given by other plugins respective to yours reference one?

I did It. I tried 4 metering plugins apart of this one, and with the same sound in the same point (about 190 Hz), all the other plugins give values of 12~14 and LSP gives ~34.

sadko4u commented 6 days ago

The level of the specific measured frequency depends on:

Which ones does your reference plugin use? LSP Spectrum Analyzer applies additional gain compensation to make the measured values almost equal among changing size of the FFT window.

sadko4u commented 6 days ago

Added +12 dB compensation on measurement. Two pure sine waves at 0 dB amplitude at the input of plugin. изображение

sergionexus commented 6 days ago

My reference plugin is T- Racks. This is the info in the T-Racks Manual:

•FTT Size: the filter size can be 2048, 4096, 8192, 16384 and 32764 samples.

•FTT Overlap: the overlap speed can be at 2x, 4x, 8x or 16x.

•FTT Window: the Window can be Hann, Hamming, Blackman-Harris, Flat Top style or no window.

•Filter Size: the filter size can be 1, 1/3, 1/6 or 1/9 of octave.

•Channel mode: select between L, R and L+R.

•Range: the ranges of vertical scale of the RTA can be set in -130…+5, -90…0 or -60…0.

•Release: set the release time of the meter between 250ms, 500ms and 1sec.

•Peak Hold time: it is possible to visualise the peak in the spectrum and here you can select for how long.