I assume you're using it a lot and then it's intuitive. For novice it's not. If I click on bottom part will it operate in another direction compared with clicking on top part? Or what about if I click on left or right edge? Can I also move mouse up-down and left-right or is only one direction allowed? Is mouse-up turning knob up or down? Are these rules same in all software or knob behaves slightly different everywhere? I have no idea for any of that except if I try and see. And since I rarely use them it's always a source for frustration.
Especially compared to linear slider which is impossible to misunderstand and you can't operate in it wrong way.
How I see it [1], absolute values don't matter audio software, except when working with loudness compliance or some very technical things. What's important is how things sound, and it's generally a bad practice relying on UI metering to dial in sound in most cases. The typical audio work involves fine tuning parameters until things feel right. In UX terms, relative parameter tuning is the most common kind of interaction, and sliders absolutely suck balls at it, in my humble opinion.
Linear sliders actually have more inconsistencies across implementation than knobs, that have converged to more or less the same pattern. E.g. some sliders reset value if you click in the middle of it, at which point all prior tuning is lost - this is super annoying and I hate it. Others operate in relative mode and they're similarly intuitive in regards to which direction they should operate depending on slider orientation (should horizontal slider change its value with up-down movement? should interaction range extend beyond slider length?). Also, such sliders are identical to knobs, essentially, but take more screen space.
So, in a a nutshell, knobs are superior for fine tuning, which is 90% of all audio software interactions.
1. I'm not a professional, but I have clocked in thousands of hours into DAWs and other related software over the years as a hobby, also I played on a few local gigs and made some simple audio software.
The shortcomings of sliders you mention are down to shitty implementations. I have never seen a slider that resets if you click in the middle of it; that's a crap UI. It's common to simply have a little reset button next to a variable control.
"should horizontal slider change its value with up-down movement? should interaction range extend beyond slider length?"
Of course not to both. I've never seen either one of those behaviors.
Knobs are bad for fine adjustment, because the closer to the center you click and drag, the more drastic the adjustment per pixel of dragging.
I don't think this is the case. Knobs are very convenient and more compact than sliders, in my personal opinion (I did a lot of audio work in the past). Manufacturers create realistic UIs because they sell better due to various perception biases (brain interprets something as sounding better if it has a UI resembling an SSL console, etc.).
> Knobs are bad for fine adjustment, because the closer to the center you click and drag, the more drastic the adjustment per pixel of dragging.
This is incorrect. In almost all pro audio software knobs are operated with a vertical drag movement. Holding a modifier key increases movement precision. I definitely have seen the behaviour you described, but it was maybe in a very old VST plugin probably two decades ago.
> The shortcomings of sliders you mention are down to shitty implementations.
Sadly, it's quite common. Three modern examples from the top of my head: Renoise, Reaper, Max/MSP. Unlike knobs, sliders can be quite random in their implementation.
> It's depressing that audio software still widely subjects users to this skeuomorphic failure
May I ask, which software are you using? The original argument suggests we're discussing pro audio, but I can't recall seeing neither angular knobs, nor 'small [reset] buttons nearby sliders', and I've used a lot of different DAWs and plugins, so maybe we're talking about something else here?
Let's see, going through the audio apps I've relied on the most... Back in the day it was Sound Forge. Loved its clean, efficient UI. More recently I've found Audition to be similarly clean and tidy. But I'm not renting Adobe software anymore.
So I did a mashup in Fairlight a few months ago, partly as an exercise to see if I could actually do anything resembling precision audio work in it. Like most of the "integration" in Resolve, it seems clumsy. The Effects UI is crammed into tiny panes and generally obtuse. There seem to be redundant instances for several types of parameters, but admittedly I'm not an expert in it. Effects will just stop working and you have to delete them from the chain and re-add them, though.
BTW, Resolve is where you can find widespread "reset" buttons, particularly on the Color page. I feel like these are pretty common in various media applications (including one I've written to control physical media devices, where I had them on sliders). Most audio plug-ins I've used have Reset buttons, although most of those may be for an entire effect rather than individual controls. I'll have to take a look at Ozone; I got that for timbre-matching recordings from different mics a while back.
I started to buy Pro Tools a couple years ago, but Avid's purchasing system (SalesForce, IIRC) was broken at the time and they just sent me a trial license as a workaround. Never got around to following up. Most of what I do with audio is destructive fixes or adjustments to files; for that, Twisted Wave does most of what I need and can host VST or AU plug-ins for anything else.
But, I would like to do more in a more "professional" and non-destructive environment. I'm considering the Logic Pro bundle, since it's relatively cheap and perpetual. Any thoughts on Logic? I tried it for 15 minutes right after Apple bought eMagic and wasn't impressed with the UI; but obviously it could be (and probably is) worlds away from that now. I remember reading a discussion that was generally positive, but some people called out a fundamental flaw in it... maybe its lack of pre-fader effects? Does that sound right? I'm not very experienced in this type of audio app and routing within them.
They're different everywhere.
My own opinion is that on-screen knobs for audio-type work can be fine as long as one can grab any part of the knob with the mouse and adjust it by moving the mouse up and down (er...well, physically forward and back).
But things are not always this way so it seems that opinions vary.
Just no.
