There are a number of audiobook torrenting sites available where you can download audio books for free, but some torrent sites don't work properly. Here's a thing I wrote on the sister posting.If you are an avid audiobook lover, here is the good news that you don't have to buy audio books from the store all the time, for they are much more expensive than e-copies. I think the name was the only thing that ever changed. This is the text version of the equalization effect. If you have an announcing voice that goes down that low, "NBC Radio News on the Hour," that might not be the filter for you. It's a terrific compromise but you can still fake it out. It's a close cousin to the rumble filter seen on sound mixers and in particular field mixers for exterior movie sound tracks. If somebody forced me to describe the damage, I'd say the 0Hz to 2Hz "DC level" was wandering giving the apparent effect of overall waveform rising and falling.īoth Butterworth and Chebyshev are messy, just in different ways. Hopefully that will fix both the waveform symmetry issue and the low-frequency trash issue. I'll look into changing the equalization/high-pass filtering step with something better (low or zero phase response). From what I've read just now, a Butterworth filter has nonlinear phase response, which likely explains the differences we see. It sometimes pushes the wave form up or down more than the equalizer does, which then causes the top or bottom to look clipped after the soft limiting step runs. I've noticed that it often changes the waveform differently (visually) than the equalizer. I suspect all of these differences are from using a fourth-order Butterworth high-pass filter (the "highpass4" function) instead of an equalizer in the "equalize" step. If you zoom in on the waveform that looks clipped on the bottom, you'll probably see that it's not actually clipped (the peaks just all line up). To be honest, I don't know exactly how it works, but the limiting step in my plug-in should be identical to the soft limiter in the Limiter plug-in because I'm using the exact same code. The "hardlimit" function is used by the "softlimit" function. The mention of "brick wall" is from limiter.ny (Steve Daulton's Limiter plug-in). (Those are done in exactly the order as listed, top to bottom.) (limited (softlimit normalized thresh hold))) The top one is classic mastering, the bottom one is Master Audiobook.Ĭode: Select all (let* ((equalized (equalize sig)) We will know, because that kind of trash can keep you from passing ACX. Also, many home microphones produce low pitch trash because, who's going to know and after all, it's expensive to fix and everybody looks at the price first. It makes no difference in this particular case, but in the field, microphones can produce low frequency garbage that can be louder than the show. The high pass filter doesn't have quite the moxie (technical term) that Low Rolloff does. The last step, Soft Limiter, gently pushes all those overloading peaks back into compliance with no harm done.īecause the formerly overloaded peaks have very low RMS/loudness, this peak correction makes little or no difference in the final outcome-except to pass ACX. But this doesn't matter because Audacity works internally in 32-float format which doesn't overload. It's perfectly normal for the sound channel to overload and send peaks above 100% in order to get the RMS volume correct. Classic Mastering intentionally creates distortion at the RMS Normalize step. Note the same passage with classic processing (on top) is clean and symmetrical like the original, and only if you're paying strict attention do you find that the overall volume has been boosted very slightly and the fine tips of the peaks have been compressed to meet the ACX peak specification.Īnd I may know why. Master Audiobook (in the middle) has significant wave distortion with non-symmetrical up/down overall bending and the first word has significant negative waveform compression missing in the positive.
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