Refined Audiometrics Laboratory PLParEQ1

PLParEQ1 has been updated to version 1.15, which comprises a massive rewrite and bulletproofing against a myriad VST hosts. All runs just great now. Cubase SL 1.06 can run 2 simultaneous instances of PLParEQ1 in Quality level 5 without choking or any discernable dropouts. Can save and restore projects with Quality 5 settings in them.


  • Stereo, Middle, Side filtering options, independently for each filter.
  • Filter #4 was incorrectly wired by the GUI to respond to Type of Filter #1. Fixed.
  • Fixed clicking on parameter changes.
  • Added bulletproof thread-locking memory management.
  • Fixed interactions between memory allocator and multiple host threads for improved stability (i.e., no more crashes)
  • Changed default Q = 0.707 (critical damping), and default Frequency = 1 kHz.
  • All starting parameters into reasonable values on initial load.
  • Fixed a glaring error that caused a crash when shared input and output VST buffers were passed to a non-block processed filtering operation. Triangular dither to 24 bit output results from double precision internal computations.
  • Made minimum block size = 512 samples at low SR, and 1024 samples at high SR. It was found that 256 samples was just too short, too often, to be a very decent filter. Quality 1 => 512 samples at low SR, Quality 5 => 8192 samples at low SR. You may have trouble running live with Quality 4 and 5. But these high quality settings are usable during track bouncing.
  • Made the denorm dither significantly below the dither used for conversion from double to float. Noise floors are now down around -149 dB RMS Wide, and essentially a flat (white) spectrum at around -188 dB/root Hz.
  • Added dither to all conversions from double back to VST float.
  • Change Q slider to use logarithmic scaling. This gives better resolution for the lower Q values. Also increase Atten range to -40 dB

Download PLParEQ1 from the Refined Audiometrics website.