Hi recently i have tried to implement an EQ, that is bit perfect at neutral position. The approach was to mix as much dry signal as possible to the filtered signal. But thanks to Own and Nicu, we have noticed that this destroys the desired filter behavior, because of the phase shift introduced by the filters.
The current master version only uses the dry signal until the Eq is touched the first time. Unfortunately you cannot go back to bit perfect without disable the EQ in preferences. For filter calculations we use the Butterworth filters from fidlib http://uazu.net/fidlib/ It also offers some shelving audio filters, but I do not now if they offer a solution here. ------------- Is is possible to build a Bit perfect EQ? There are a lot of academic docs on the web, which describe how to phase compensate Filters. Is there a solution for us? The easyest way ist to run the filter again in posit direction (filtfilt()), but this is not possible for live audio. Does anyone have experience with linear phase filters? Is there a Linear Phase EQ in the Foss domain? Audacity has a FFT EQ: https://github.com/mcpierce/audacity/blob/master/src/effects/Equalization.cpp What are the pros and cons? Thank you, Daniel ------------------------------------------------------------------------------ HPCC Systems Open Source Big Data Platform from LexisNexis Risk Solutions Find What Matters Most in Your Big Data with HPCC Systems Open Source. Fast. Scalable. Simple. Ideal for Dirty Data. Leverages Graph Analysis for Fast Processing & Easy Data Exploration http://p.sf.net/sfu/hpccsystems _______________________________________________ Get Mixxx, the #1 Free MP3 DJ Mixing software Today http://mixxx.org Mixxx-devel mailing list Mixxx-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mixxx-devel
