PGGB•IT! already supports EQ using the import capability built into Remastero PGGB (using the PGGB-EQ tab). In this case, a measurement file is imported into PGGB_EQ and converted to a high precision internal format for use in PGGB•IT!. The imported file (convolution wav) requires a microphone and external program, like REW, to adjust for loudspeaker/headphone frequency response or to accommodate room correction. Alternatively, a file (parametric txt) can be sourced from a database of measurements or manually created using RoomEQ or AutoEQ.
While this method allows for absolute equalization control, its somewhat complicated for ad-hoc EQ tuning. Moreover, it requires the installation of Remastero PGGB which itself requires installation of MATLAB. I wanted a simpler way... so a four band EQ mechanism was developed: 20Hz low-bass, 125Hz mid-bass shelf, 1.5 kHz mid-treble shelf and 20 kHz high-treble, as per the diagram below.
The upcoming version of PGGB•IT! (5.7.0) will include this feature. Each frequency band is controlled by a dB gain setting. Now, without requiring a frequency response measurement, users can use their ears to tweak bass response, add high frequency sparkle and fill gaps in their sound.
Regarding sound quality, PGGB EQ is 100% mathematically lossless, which means EQ still retains full transparency of the reconstructed signal. PGGB EQ processing at 256-bit precision beats out professional audio mastering at 64/80-bit precision, Mojo2 at 104-bit precision or HQ-Player at 64/80/128-bit precision. And PGGB EQ's superior algorithms result in the utmost fidelity:
- Filters are ultra-long, linearized and customized for each sample rate
- High precision avoids amplitude or phase noise.
- Processing is non-cascaded to eliminate distortions
- Ideal pipeline of reconstruction ⇨ EQ ⇨ Noise shaping
- Bands are processed in parallel for increased performance
In my listening tests: the frequency response of my PMC MB2S loudspeakers dips at the low end so I applied a EQ of +6 dB on the 20hz band and +1 dB on the 125 Hz shelf. The result was a much improved bass definition and a striking fullness of sound — without losing any of the wonderment or transparency!
PGGB•IT! upgrades are free. All registered users will receive notice for this version. I am also hoping to include this feature in an upcoming PGGB-RT/foobar release.