Re: [Audacity-quality] Delay effect - what do we want to do about it?
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From: Steve t. F. <ste...@gm...> - 2012-07-22 21:43:31
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I think we're probably guessing at "main use cases". Perhaps the reason no-one complains about the change pitch effect is because nobody uses it. If I wanted to use delay with pitch shift I would find the current version to be unacceptable because it does not maintain the correct delay time. However, that said, I'd probably not complain about it but just accept that it didn't do what I wanted and create the correct effect by manually making several delayed duplicate tracks and use the Sliding Time Scale / Pitch Shift effect on them. I can't imagine the current delay effect being accepted into Audacity if it were submitted now. Perhaps we should completely rethink the delay effect and replace it with something more "professional". How about a multi-tap feedback delay? http://audacity.sourceforge.net/manual-1.2/effects_delay.html Steve On 21 July 2012 19:53, Gale Andrews <ga...@au...> wrote: > > | From Steve the Fiddle <ste...@gm...> > | Sat, 21 Jul 2012 14:54:06 +0100 > | Subject: [Audacity-quality] Delay effect - what do we want to do about it? >> On 20 July 2012 19:39, Gale Andrews <ga...@au...> wrote: >> > >> > | From Steve the Fiddle <ste...@gm...> >> > | Fri, 20 Jul 2012 15:38:45 +0100 >> > | Subject: [Audacity-quality] Delay effect - what do we want to do about it? >> >> On 19 July 2012 23:34, Gale Andrews <ga...@au...> wrote: >> >> > >> >> > | From Steve the Fiddle <ste...@gm...> >> >> > | Thu, 19 Jul 2012 15:35:06 +0100 >> >> > | Subject: [Audacity-quality] Delay effect - what do we want to do about it? >> >> >> Before we commit to throwing out the Nyquist pitch shift option I'd >> >> >> like to suggest that the QA team (and any interested developers) give >> >> >> it a little test. >> >> >> >> >> >> We know that the Nyquist pitch shift effect is not brilliant and we >> >> >> know that percussive sounds show up the effect most. >> >> >> We also know that long selections show up the weaknesses in the >> >> >> current (resampling) method for pitch change, so I think that this is >> >> >> a fair test to show up the weaknesses in both algorithms. >> >> >> >> >> >> 1) Install the two attached plug-ins. >> >> >> "Delay v2" provides an option for both methods of changing the pitch - >> >> >> the default is the Nyquist pitch shift method. >> >> >> "Delay v3" provides only the old, resampling method. >> >> > >> >> > As presented, v3 appears to offer both methods but allows pitch >> >> > shift to be commented out? >> >> >> >> Oops, sorry, I forgot to comment it out again after testing. >> >> Line 20 in delay3.ny should have an additional semicolon at the start >> >> of the line: >> >> ;;control pitch-type "Pitch change method" choice "Change Pitch,Change speed" 0 >> >> >> >> >> 2) Generate a click track with default settings. >> >> >> >> >> >> 3) Duplicate the track. >> >> >> >> >> >> 4) Apply Delay v2 to the first track and Delay v3 to the second track. >> >> >> Settings: >> >> >> * Delay level: -3 >> >> >> * Maximum delay time: 0.1 >> >> >> * Pitch change per echo: -1 >> >> >> All other settings at default. >> >> >> >> >> >> 5) "Listen" to each track in turn. >> >> > >> >> > So I applied Pitch Shift to the first track in v2 and Speed Change >> >> > to the second track in v3. >> >> > >> >> > >> >> >> I think that this type of effect falls into the "special effects" >> >> >> category, so the "perceived effect" is probably a lot more important >> >> >> than mathematical accuracy. >> >> >> >> >> >> I've tried to look at this from a user's perspective, and as such my >> >> >> preference is for version 2 - I'd rather be given a choice of which >> >> >> pitch change method to use. As a user I don't need a deep >> >> >> understanding of what it is doing, I can try it and decide which >> >> >> effect I prefer the sound of. >> >> > >> >> > Obviously the pitch shift sounds "better" there than speed change >> >> > (unless the user wanted something that sounds "random" rather >> >> > than more "regular"). Pitch change is only somewhat more regular. >> >> > It still "sounds" speeded up at the end, largely because the >> >> > (unasked for) extra echoes seem to be louder than they are at >> >> > the start. To demonstrate that, copy the first two and final two >> >> > seconds of the result to separate tracks and compare them. >> >> > >> >> > So I still think the pitch change is worse than speed change, more >> >> > difficult to document, and it should definitely not be the default. >> >> > The new term "Maximum Delay Time" is even worse than the >> >> > previous term "Delay" for pitch change - the first delay AFAICT is >> >> > always *more* than the "maximum". Should it be "target delay"? >> >> > As far as I understand it, the delay time is accurate with speed >> >> > change (if you allow for the speed change). >> >> > >> >> > I think the choices are: >> >> > >> >> > * As per your previous e-mail - consign "pitch change" to an >> >> > optional Delay effect (and perhaps add other weird effects >> >> > to it - can you think of any?) >> >> > >> >> > * Perhaps have your two pitch change options but change "Pitch >> >> > change method" to "Pitch change effect" then have "Pitch and >> >> > speed" (default) and "Pitch with delay" (or some such) as the >> >> > effect choices. >> >> >> >> It's not really a "pitch with delay" effect. The "reverberation" in >> >> the pitch stretch is an artefact of the pitch stretching method. The >> >> Audacity "Change Pitch" effect has the same problem, though less >> >> severely (try applying "Change Pitch" to click track and you can hear >> >> and see the same type of "reverberation"). It is an inherent problem >> >> with the "overlap-add" method >> >> http://en.wikipedia.org/wiki/Audio_timescale-pitch_modification#SOLA >> >> >> >> How about replacing "Pitch change method" with "Per echo effect" >> >> with choices for: >> >> >> >> "Change Speed" (the old "Pitch change") >> > >> > But it also changes pitch, so must mention speed and pitch if >> > the label is "Per echo effect". >> >> The effect on each echo is identical to: >> http://manual.audacityteam.org/manual/help/manual/man/change_speed.html > > It doesn't seem reasonable to me to so completely change the > label for existing users. Anyone using the current pitch change > would choose the new pitch change and get something very > different to now. > > Personally if I use delay I only do so on short selections and only > the pitch change is obvious. > > >> >> "Low Quality Pitch Change" (could be abbreviated to "LQ Pitch Change") >> >> "Damping" (a low pass filter) >> >> "Reverb" (a simple reverb effect) >> >> >> >> I think these would be useful additions to the Delay effect. >> > >> > Is "Reverb" confusing if LQ Pitch Change also creates reverb? >> >> I don't think so. The "Reverb" effect would be a proper reverberation >> effect. At high settings it would reverberate for several seconds. >> >> On the other hand, the "reverberation" caused by the LQ Pitch Change >> is just an artefact in the time domain that (at worst) creates a >> couple of repeats for around 60 ms. > > Then the "Reverb" effect with the default setting needs to be > strong enough to be audibly different, I feel. > > >> > Should it be "HQ Reverb"? Do we need it at all if we address >> > GVerb in the not too distant future? >> >> This is still primarily a "delay" effect, but we are transforming each >> delayed signal by routing it through a second effect. >> What I'm suggesting is that rather than just the one "Change Speed" >> transformation that is currently available, we make other interesting >> transformations available. >> > >> >> The "Pitch change per echo" slider would then become a generic "Effect >> >> Amount (%)" slider where 100% = 1 tone for the Change Speed and LQ >> >> Pitch Shift. >> > >> > How are you going to get across that 100% = one tone for the >> > two pitch changes unless you have "LQ Pitch Change 1 tone"? >> >> Separate options for pitch up and pitch down? > > That only seems slightly better - you still don't know that > 100% is one tone without reading the Manual (unless the > option states it). > > With the current effect you know the pitch change on offer. > > >> > Might not someone want to damp as well as pitch change in one >> > pass? >> >> That's hypothetical but if they do then we can consider that as a >> feature request. > > I still think it's needlessly confusing and inflexible to bundle > pitch changes with unrelated effects in one control. If the > two pitch changes were separate they could go at the > bottom as probably less useful than the new damping and > reverb. > > > > > Gale > > >> Steve > > > > ------------------------------------------------------------------------------ > Live Security Virtual Conference > Exclusive live event will cover all the ways today's security and > threat landscape has changed and how IT managers can respond. Discussions > will include endpoint security, mobile security and the latest in malware > threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ > _______________________________________________ > Audacity-quality mailing list > Aud...@li... > https://lists.sourceforge.net/lists/listinfo/audacity-quality |