Actually it still produces quite some images but they get filtered out reasonably good with Audirvana's Anti-Aliasing filter (set to 100). Steepness: 22 and cutoff 0,95 (and pre-ringing 0,36). The ringing is very low and there are absolutely no images (artifacts above the nyquist limit of the source file).Ī settings with as low ringing as possible and a roll off of high frequencies also starting at around 18kHz is Lowpass filtered with Fabfilter (2 filters at 18kHz and 19050kHz, both high cut -96db/octave):
Here's a single pluse usampled in iZotope with above mentioned "extreme settings" and high cut filtered with FabFilter Pro Q2 in so called "natural phase" mode. Looking forward to your answer regarding the additional low-pass filter. It’s a compromise (as always) but I am happy with it… Instead I’ve tuned my „online“ settings in A+ to work with all source sample rates … if you want so, my „set it and forget it“ settings that reliably filter out images with a lowpass filter starting to set in at 18kHz (referring to 44.1kHz source files) and with pretty low ringing and moderate pre-ringing. I still think it would be the best approach, but it’s simply too much work.
Personally I’ve skipped the adventure of upsampling my entire library offline … because it takes ages. There are still some images … but they do not exceed -100db… so really nothing to worry about. Too, in your screenshot it’s set to around 7kHz or 8kHz… which is extremely low.įabfilter Pro Q2 for instance features a -96db/octave lowpass filter and you can stack it.Īttached a screenshot of a 44.1kHz file upsampled with the „extreme“ settings (3 - 1.25 - 50 - 0.36) with and without lowpass filtering (the two filters are set at 18kHz and 19.5kHz… both -96db/octave). Then again the steepness of Apple’s built in lowpass filter is really not sufficient.
Afterwards you have to filter out the images with a lowpass filter in the AU plugin section. Once you get past the stock settings, it's a hair here and there.Sorry for the late reply… in fact I don’t visit the forum frequently.īasically you are right: the SRC settings (intentionally) produce a large amount of artifacts („images“) due to the very low steepness of the filter. I also thought that filtering out the aliasing images above the nyquist using the EQ helped clarify the audible spectrum - but this could just be brain trickery. I tend to favor fewer pre echos at the expense of more post echo because I value "attack" over "separation" and I listen to very congested music with tons of instrumentation (prog rock). After that there are super small differences detected in the steepness and pre-ringing settings as this changes the pre and post echos of transients. The biggest difference I heard was in using stock settings in forced upsampling (power of 2) vs not using it.
Even with my TOTL IEMs I was hard pressed to hear real differences. Of course, if you don't have very fast and resolving headphones/IEMs (and amp), you may not hear a difference. In my case FabFilter ProQ 2 - I have 96db/oct at 18khz and another 96db/oct at 19.5khz - I run in "natural phase" modeĪll of this is covered in detail in the PM I'll send you. These settings are best matched with a low pass filter scheme and VERY good EQ software.
limit your software output bit rate to match the max of your DAC - in my case I limited it to 24 bits down from 32 (I swear I heard a difference, but it was hard to tell).I'm just a copier here, not original poster! In the meantime, here are some settings I've been using with A+ and iZotope upsampling that I've basically copied from the link I'll provide to you.