Airwindows Meter (v0.1.9): Free Mac/Windows/Linux CLAP/AU/VST3

TL;DW: Meter uses analysis of peak energy to rate songs for hit potential.

github.com/airwindows/Meter/releases

Here's Airwindows Meter v0.1.9, with even more interesting color mappings! I'm sorry the explanation is so long-winded, but this is (for now) literally unique and doing something that's never been done before. Three out of four meters here are unique and the peak meter doesn't work like anybody else's peak meter, either. So, everything that it does, takes some explaining. If you don't want that, just run lots of reference audio into it and learn how to make your audio more like your references by matching the behaviors and colors. That's fine too! Still here? OK, here's how it works.

Top meter is a peak meter. NO RMS, only peak. On modern music it will show just a line of clipped bad sound, with the top of the meter representing 0dB. All the other parts also refer to what's happening to peaks. There's no display of RMS at all: that's for pretty much every other meter, and not interesting here. One exception: bass dots are sized according to RMS, so if you see a burst of green dots you know that's a bass event and can adjust it accordingly. You still want to make 'loudness' in this our modern world, but it is done through making a dense cloud of peaks from 0dB to however far down you like: -12dB or -18dB are not unusual. These are shown as dots: the color dot most likely to give you good results is blue dots. That means the loudness is being balanced by brightness correctly. If you clip there's a discreet red line down at the bottom, but you can still see what's happening with the other peaks.

The second (now half-height) display is a Slew meter. It's showing exactly the same information, but organized differently. On the slew meter, brighter is higher up. (if you have red/green color blindness, 'gred' dots above the blue dots are brighter, and below the blue dots are darker/bassier). On this meter, the red (bright) dots are drawn more obviously, and the green dots are a lot more subtle because it's the 'bright' meter and bassy stuff is the backdrop. This too can produce red warning signs at the bottom, 'over-slews' meaning your stuff threatens to be way too bright to sound good. This meter also gives you a running average of the brightness of your peaks: having bright and dark in balance is good, but you can either balance them or just have everything 'loud' and rely on sonority. That works too.

The third (now half-height) display is a Zero Cross meter. That represents the bass balance: if a low tone is causing the waveform to go many samples without crossing zero, and you make high frequency information louder, you'll interfere with the Zero Crossing and it'll fail to register the bass (just as the listener will fail to hear the bass if you've got the balance wrong). This one's marked in hertz: a line up top shows 200 hz (common for old retro sounds that lack bass, and there'll be a cloud up there if you don't have good bass extension), then there's another line at 40 hz (of interest to dance/EDM producers) and the bottom of the meter is 20 hz. This will immediately show you if your sub-bass is absent or out of control, no matter what speakers you have. The dot size shows RMS here (like the green dots on the Peak meter)

and with a little practice it should speak volumes to anybody needing to work with heavy and deep bass and have it translate.

The fourth display, previously a simple chart for some internal parameters, is now a lot more interesting! It now shows three parameters against a colored background.

Sonority acts like the intensity of the peak loudness. Even if you're not clipping or limiting, if this is high then your music will rip right out of any playback system and make other stuff sound weak. Sonority means every inch of display is packed with blue dots (representing peak energy, lots of it, all of it near the top of the meter). If you had a super-narrow band of solid blue right against the top of the meter, this is basically the same as modern loudenating, just with a slightly better flavor about it and less digital edginess to it (if it's over-bright, the dots will no longer be blue).

Novelty is important. If you have a dense cloud of blue dots, Novelty shows how wide a range they're covering. This can be as wide as 0dB to -18dB or even -24dB (seen in some classic Talking Heads, Parliament, James Brown etc). You'll see the cloud of dots covering more space on the top meter if Novelty is reading a high score, and it's an important part of hit record sounds that are big, wide, open and appealing, not just 'painful to listen to'. This measurement is key to many hit records. Note that you can only get it to work by having something happening at all volume levels at once: just going really quiet isn't going to help Novelty that much. The time period it responds to is roughly like human breathing, but the best way to enhance it is to clean up the mix so it relies on peak energy more.

Intention is the green line that represents the letter score people care so much about: if it gives you a score, that's the highest this line got (there is a discreet reset button top left that will restart the meter). On the bottom edge of the zero cross meter, there are reminders of what these lines mean, and Intention is 'both plus balanced tone, minus RMS'. This is your star quality score, your hit score. You can't make it better just by going louder unless you're simply not using all your dynamic range for peaks. You can balance brightness with bass extension, and you can try to get either the peak density or the range to be greater, depending on if you want to sound loud and aggressive, or open and inviting. Or, you can do a little of everything.

The background color varies to show the 'sound color' of your result. This one I can't make red-green color blindness friendly, but some parts of it will still give helpful information. So, on this, green is your hit record color, but it's your POP hit color. On this background color, red is 'dark' and blue is 'bright'. That makes the green a 'colder' shade of green if it's over-bright, and a red or yellow if it's dark and lacking in treble detail. However, there's one more twist: the green's also modulated by whether Sonority or Novelty are higher. If it's all Novelty and open airy spacey poppy textures, that's a super-bright green, to the point where the line across it goes white. This is very common in hit records. But if it's all Sonority, and still a hit record sound, and still balanced, the meter will go nearly black! And that's also a hit sound, but it's more an underground, metal, aggressive sound, pummeling you with loudness and intensity. And then, another classic sound (heavy rock, old Led Zeppelin) involves having all of these lines very close together, so it's balanced and neither too open or too dense, for a deep green. Remember that Sonority is not just loud peak sounds, but how densely different peaks are packed against each other, and Novelty is how widely they're distributed in dynamics, versus just getting blasted with peaks all of which are loud. In other words, your 'target' might be the brightest green, or total black, or anything in between.

In this version, all the chart lines have the same ballistics and drop back to zero when nothing's happening: only the letter grade stays at maximum. This is a big change from previous versions, but it's producing much more reliable ratings than before, so I'm prepared to put it out and get back to using it for a while, rather than simply developing it. I'm confident that working actively with music's peak energy will work out well for people. In fact, I'm looking to integrate a version of this into ConsoleX when I've finally got that ready to go: there won't be room for the whole thing, but I think I can do a '2-d' version of a Novelty meter combined with the blue/red/green peak coloring and have something that'll show useful information in a much smaller space.

Deciding to make slew and zero cross half-height turned out great! Thanks to Jrel at gearspace for the suggestion. Meter v0.1.9 should fit much better on a broad range of screens: it doesn't really lend itself to being resized but ought to handle it fairly well, in particular it ought to work at many different widths and still function. I hope this gives you a new window (indeed, an Airwindow!) on your sound, as it does for me.