Re: Resampler plugin
Reply #158 – 2011-02-14 21:48:35
Meridian and some other high-end companies like Ayre claim that their new upsampling "apodizing" filters can help sound quality by minimizing pre-echo. Unfortunately, my older Meridian processor doesn't implement these new upsampling filters. Someone on the Meridian forums has been trying to reproduce a filter which has an impulse response like the Meridian filter using a SOX plugin for their squeezebox server, see: http://www.meridianunplugged.com/ubbthread...5273#Post125273 Unfortunately, the SOX filter which has an impulse response which looks closest to the Meridian one has a passband parameter of 87.5% which is lower than the GUI for your plugin allows. From reading the thread on the Meridian forums it looks like setting a low passband on these filters helps shape how fast the post-echo tails off. All over the net i see that funny graphs of pre and post echo. Can anyone help me interpreting these? As i interprete these graphs the post and pre echo that these pics show consist of frequencies "above the cutoff" that is applied. So they are out of the audible range. I wonder why people hear all kinds of problems with noise that happens above there at a very low amplitude. To get rid of that people use low-pass filters that come in way deeper in frequency and therefore may alter the sound much more as the original echo. Am i wrong? Of cause from a marketing point pre-echo is evil and can be easily shown with a simple graph. I wonder how many % of the people looking at these pics realize the shown echo is happening above their hearing.