On January 17, 2016 06:28:13 PM Tim E. Real wrote: > Hi. > Just wanted to mention last week while doing research > on channel strips and markings, I was surprised and > reminded that many /other/ mixers show VU or logarithmic > markings, where the lower part is all skrunched up > and the upper part is sparse. > > Well, it turns out MusE, either intentionally or by natural > programming instincts, uses a system resembling > the 'K System' proposed by Bob Katz. > > MusE is using 'K-10' meters, as it were. > > To me it seems just logical and natural that our markings and > slider steps are in Linear Decibel. > We are showing peak level in linear dB steps. > And our slider is in linear dB steps. > Very easy and 'just natural' in code. > Just a log conversion from peak signal value to peak dB. > > Looking ahead, we could support other metering systems. > RMS and so on. > > Tim. >
Want to also mention, in case anyone wants to tackle it: Our audio meter system has an observable flaw, have you ever seen it? The meters can 'flutter' and can even be made to stand near-still at some arbitrary value, including zero even when there clearly is an audible signal. It happens within certain, usually lower, signal frequencies. If you look at the meter code in node.cpp you'll see why. We take the peak of the set of samples of /one/ cycle and update the meter with /that/ value each time. So with certain signals it's possible to have (almost) nothing there during these sample portions. I saw Andrew made some 'falling' meter fixes but I think they were just for the midi strips (moved 'falling' stuff out of strip and into meter itself, using timers). This 'falling' code could be one way to help smooth out the fluttering in the audio meters. Yet, at some point we /need/ to start sampling over more cycles, for average values, RMS, better peaks, less fluttering (alternative to 'falling' display). TODO: Perhaps we should sample over as many cycles as it takes to give an effective low-frequency response of say, 10 or 20 Hz. Below that, well you got fluttering, eh... Ironically 20Hz is our default heartbeat GUI update timer rate - the rate at which the meters are updated... Tim. ------------------------------------------------------------------------------ Site24x7 APM Insight: Get Deep Visibility into Application Performance APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month Monitor end-to-end web transactions and take corrective actions now Troubleshoot faster and improve end-user experience. Signup Now! http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140 _______________________________________________ Lmuse-developer mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/lmuse-developer
