FabulousMP3 User's Manual - Meters for multiband compression processing

FabulousMP3 User's Manual

Meters for multiband compression processing

The following descriptions are about the sound meters or indicators on the main window.

STEREO ENHANCE LEVEL

This is the peak level meters for the stereo enhancing function. This shows the (L-R) signal level mived to the mail audio line. This scale is linear and its unit is not "dB". The maximum level "100%" is equivalent to 16bit digital audio range "+32767".

INPUT LEVEL
This is the input peak level meters. This scale is linear and its unit is not "dB". The maximum level "100%" is equivalent to 16bit digital audio range "+32767".

AGC: Limiting ratio of input sound level
This shows the limiting ratio (dB) of 2 band AGCs (Automatic Gain Controllers) just after the input. The recording level of every song is deferent. This AGC will uniform the sound level sent to the multiband limiter in order to get the best effect. The level bar shows the limiting ratio.This AGC has crossover at 200Hz and the low and high bands are processed separately.

Pre-emphasis Limiting ratio and HF level
These meters are for the pre-emphasis adjustment. FabulousMP3 supports 50us / 75us pre-emphasis for FM broadcast. Over 2kHz is boosted with 6db/oct slope for 75us pre-emphasis, and over 3kHz is boosted with 6db/oct slope for 50us pre-emphasis. In order to avoid clipping of high frequency band by pre-emphasis booster, FabulousMP3 has an HF limiter. These meters shows the HF limiting ratio(dB) and HF signal level (%).

Multi Band Limiter(dB): Limiting ratio of each band
This shows the limiting ratio (dB) of each frequency band separately. The level bar shows the limiting ratio and a scale means -1dB. The red lamps under the meter are clipping indicators for each band. The clipper is located after the multiband limiter. It cuts the unnecessary peaks and suppress the signal to a certain level. This clipper is, so-called, "Soft knee" clipper and the distortion sound can be soft like a vacuum tube amplifier.

OUTPUT LEVEL
This is the outout peak level meters. This scale is linear and its unit is not "dB". The maximum level "100%" is equivalent to 16bit digital audio range "+32767". The red clipping indicator lights when the final output just before the de-emphasis filter would overshot -0.2dB.