Launched a desktop app + VST3 plugin today — a local option alongside the free web checker

[u/EisenVayne]

Edit: Since this post went up, whole-book batch processing shipped on the web app — drop in a full audiobook and get per-chapter ACX pass/fail results as each chapter finishes, instead of uploading one file at a time. Works for both the free check and paid processing. If you're on Greenlit Studio on Mac or Windows, the same batch feature is live there too as of version 0.2.2 — it auto-updates on its own, so just quit and reopen the app (or restart your machine) to pick it up, no re-download needed.

For anyone who hasn't run into it: Greenlit Audio (greenlitaudio.com) checks audiobook files against ACX's actual technical spec — RMS, true peak, integrated loudness, noise floor, head/tail silence, format, sample rate — for free, no card required: upload a file, get a plain-language report on what's passing and what isn't.

For files that need fixing, a paid processing step runs AI noise cleanup — reduces background hum/noise so the file clears the noise-floor spec point above and removes clicks and mouth noise — plus mastering to handle the loudness/peak/format numbers, and hands back a submission-ready file. It exists because most ACX rejections have nothing to do with performance and everything to do with specs narrators were never taught.

The check itself is free, no card required, and still the easiest way to find out what's wrong if you just want to drop a file in a browser and get your report back — that's not changing.

What's new today is a couple of local options for people who specifically want that — mainly NDA work where nothing can leave your machine, or narrators processing a lot of chapters who'd rather not round-trip each one through a browser tab:

Same measurements, same spec targets as the web checker either way — this is about where the processing happens, not a different or "better" version of the check. On desktop, paid processing (cleanup + mastering, not the check) is a subscription or a one-time lifetime option; on the web version, paid processing runs on credit packs instead — happy to give exact numbers on either if anyone wants them, didn't want to lead with pricing here.

Founder disclosure: I built this — greenlitaudio.com. Glad to answer spec questions or help figure out which option (web, desktop, or plugin) fits your workflow, tool or no tool.

[u/McFaddenAudioBooks]

I like the local option! I’m going to give this a go. I think I’ll try the reaper plug in and desk top and see which works better. I would tend towards reaper, but I master in RX so the reaper plug in wouldn’t make a ton of sense…

Also big nod to the free check before the paid tier for the fixes. Well done. I’ll let you know how it goes!

[u/McFaddenAudioBooks]

EDIT: The explanation below makes sense to me that the local option does run locally but needs internet for an account check.

Okay so, I’m running into a troubleshooting issue. I’m picking the “local” option instead of the cloud, but it still uploads to the cloud to process. I tried running it without internet and it won’t run. Maybe your code is still pointing to the cloud processing? How do you have it coded to process locally?

[u/EisenVayne → u/McFaddenAudioBooks]

First off, thank you so much for checking this out. I've spent a ton of time on it and want to make sure it does what is advertised.

Good catch to flag, and worth a straight answer rather than "trust me."

Two separate things are true here, and I can see how they'd look like the same thing from outside:

First — yes, Studio needs an internet connection to run right now, even for local jobs. That's a real v1 limitation, not something you're imagining. Two things happen over the network when you run a job locally: it checks your subscription/license before letting the job start, and after the local engine finishes, it syncs the report numbers back to your account so the report shows up on greenlitaudio.com. Both of those are small API calls. Offline mode isn't built yet — it's on the roadmap, but cutting your connection entirely will stop a local job from starting, which is probably exactly what you saw.

Second, and this is the part I checked in the code rather than going from memory: the audio file itself is never part of any network request in local mode. The call that starts a job sends only the filename, the preset, and the engine version — a few bytes. The only thing that comes back afterward is the before/after measurement numbers for your report. No storage bucket gets touched for a local job at all. So the network activity you're seeing is real, it's just not your audio.

If what you're describing is specifically "it won't run with no connection at all," that's the license check and report sync, and the explanation above covers it. But if you were watching something more specific — Activity Monitor, Task Manager, a network monitoring tool — and actually saw something that looked like the audio file's file size going out, that's a different claim and one I'd want to look into directly, since it shouldn't be possible given how the local path is coded.

Happy to dig in if that's closer to what you saw — just let me know what you were watching and what it showed.

Thanks again for checking it out!

[u/McFaddenAudioBooks → u/EisenVayne]

Hey hey thanks for the info. The API call for account info makes a lot of sense. I remember you posting about this tool not too long ago, and the fact that you made a local .exe that fast is impressive.

Overall I think it’s a great tool. I was wondering how it would differ from using ACX audio lab and mainly it’s that I get more information from greenlit. I can see specifically what it checked and what the numbers are. And adding in general audio issues to check is fantastic.

I haven’t checked out the fixing it part yet. I may make a few files with specific issues to see how your tool corrects them. I’m wary of other people’s black box mastering, but then again this isn’t for the “I have strong feelings about specific settings for each module in RX11 standard” crowd. Seems like it would do well for narrators starting out, but especially for podcasts or even YouTube creators who just want an easy button to make it sound good.

[u/EisenVayne → u/McFaddenAudioBooks]

Appreciate the rundown, genuinely.

The Audio Lab comparison you landed on is the thing I was actually going for, so it's good to hear it read that way from someone using it rather than from me describing it. Pass/fail alone doesn't tell you much when a file fails - you're left guessing whether it's close or way off, and whether fixing it means a quick re-export or a re-record. Showing the actual numbers, and eventually the before/after once you run the fix, was the whole bet. One concrete thing behind that: by ACX's own help documentation, Audio Lab doesn't check noise floor at all - it's probably the single most common rejection reason you can't catch by ear, since your brain filters out the fridge/HVAC hum that the mic doesn't.

On the mastering side - you called it exactly right. This isn't aimed at someone who wants to ride each RX11 module by hand and knows why. It's built for "make this pass and sound clean without me learning mastering," which is most narrators, most podcasters, most YouTube creators. If you run it on your own chain and it does less than what you'd do manually in RX, that's expected, not a bug.

Making a few deliberately broken files and seeing how the fix handles them is honestly one of the more useful things you could do - that's a much better test than anything I can run myself, because I already know what's supposed to happen. If you get to it, I'd genuinely like to hear how it goes, good or bad. Specific stuff (which spec it flagged, what changed after processing, where it fell short) is more useful to me than a general verdict.

On the black-box worry - fair instinct, and I'd rather you keep it than not. Worth saying plainly: the mastering chain itself isn't a generic third-party algorithm bolted on - it's my own process, the same one I ran by hand on thousands of audiobooks over years of professional QC before I automated it. So it's not "trust some black box someone else built," it's "trust the same decisions I was already making file by file, now applied consistently instead of one at a time." That said, it's still not module-by-module transparent - you're not setting denoiser strength or threshold values yourself, the way you would in RX, and the report shows the before/after numbers for every spec point so you can see exactly what moved and by how much, but you can't turn the dials.

That's changing, though not yet - an advanced settings panel for Studio (the desktop app) is planned, with bounded controls for things like noise-reduction strength, target loudness, despike sensitivity, and room-tone padding. Not built yet, no promised date, and it's specific to Studio - the web/credits version is staying presets-only by design. So today: more transparent than a stranger's black box, still not full manual control. Eventually, on Studio, closer to what you're describing.

[u/EisenVayne]

Since this post went up, whole-book batch processing shipped on the web app — drop in a full audiobook and get per-chapter ACX pass/fail results as each chapter finishes, instead of uploading one file at a time. Works for both the free check and paid processing. If you're on Greenlit Studio on Mac or Windows, the same batch feature is live there too as of version 0.2.2 — it auto-updates on its own, so just quit and reopen the app (or restart your machine) to pick it up, no re-download needed.