Ask Justin Frankel

justin = { main feed , music , code , askjf , pubkey };

Ask Justin Frankel
No reasonable question unanswered since 2009!

Suggested topics: programming, music, sleep, coffee, etc.

Note: please do not ask questions about REAPER features, bugs or scheduling, use the forums instead.

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[older questions]

Question: Bought it. Name's Kamil. Cheers, man.
Asked by Mr. F (93.159.35.x) on December 31 2025, 2:16pm
Reply on December 31 2025, 4:34pm:

right on happy new year! Comment...

Question: Did you get the blessings from the open source lua/text ChordLord v4.01.235 by EatMe + Panda + Suva as tool for Renoise? ChordLord in 6 languages selects tones together (chords) in scales (do-re-mi-fa-so-la-ti-do) in harmony with the chosen scale on buttons. This automates writing chords and chord schemes for songs with 1 button per chord, out of a 235 chord library possible per tone in each of the 36 scales with up to 7 tones per scale.. You can learn harmonic music theory from this tool.
Asked by EatMe - Music by EatMe (85.148.71.x) on December 30 2025, 6:50pm
Reply on December 31 2025, 4:34pm:

haven't looked at it but will check it Comment...

Question: I'm on the fence whether or not to buy Reaper. I like the design philosophy behind it and monetisation model you chose to follow, the wording you framed it in a bit less. Hurr durr, Reaper is not free, you are required to pay me after 60 days you filthy freeloader. xd I think it's conducive to creating cult-like behavior around the software. So how about this? Denounce people in the community who shame/bully others for not having payed for it, and you have officially won me over.
Asked by Mr. F (93.159.35.x) on December 30 2025, 12:16pm
Reply on December 30 2025, 4:28pm:

I'm not going to denounce people shaming other people, but I absolutely denounce anything that falls into the category of bullying! 1 Comment...

Question: How do you edit the audio graph while the audio callback is running in a DAW? I read an articel that said you shouldn't do dynamic allocations on the audio thread. Are you supposed to allocate stuff on another thread and then atomically swap a pointer owned by the audio thread?
Asked by Edward (198.58.185.x) on December 29 2025, 4:30pm
Reply on December 29 2025, 6:02pm:

yes you want to avoid allocating on the audio thread if possible. better to allocate from the main thread or a worker thread, then swap it in. IMO doesn't have to be atomic, you can use a mutex, just want to make sure that any threads that hold a mutex (that the audio thread waits for) only hold it for a very short time (e.g. swapping pointers etc). Comment...

Question: Many of us refer to the trial version interface that pops up when launching Reaper as an "ad". Do you think this qualifies as an advertisement?
Asked by noto (221.215.214.x) on December 29 2025, 4:42am
Reply on December 29 2025, 6:03pm:

No, an ad would be if that about box tried to get you to buy other things, like breakfast cereal or plug-ins or something. 1 Comment...

Question: I'm coding a JSFX limiter, in ReaLimit even without true peak engaged it is able to keep peaks at the ceiling value and it doesn't overshoot but mine is overshooting the ceiling value. Are you using two stages of limiting in ReaLimit where the second catches the peaks? I tried putting a second hard limit stage but which caught the peaks but it was causing distortion, what second stage are u using if any? hard limit, soft limit, etc?
Asked by ReaLimit (102.176.65.x) on December 28 2025, 8:06pm
Reply on December 29 2025, 6:03pm:

schwa would probably be better to answer this -- ReaLimit uses a lookahead too, maybe that's what you're missing? 1 Comment...

Question: raspberry pi or n100 pc?
Asked by vague (149.88.102.x) on December 28 2025, 12:36am
Reply on December 29 2025, 6:05pm:

Depends on what for, seems like the power consumption of the n100s are 3x higher? depends on how much disk bandwidth you need, too, SSDs are way faster than microsd... so in general I'd say the faster thing (n100), unless you're going for cheap/low power, in which case pi. Comment...

Question: have you seen this? x.com/kmcnam1/status/2004779296196...
Asked by Ian the The (193.5.232.x) on December 27 2025, 6:53pm
Reply on December 29 2025, 6:05pm:

I hadn't, heh Comment...

Question: How do you do delta in JSFX plugin like how you've done in REAPER'S plugin window. Is it a simple dry signal minus wet signal? Any simple code snippet to understand the logic?
Asked by Delta (154.161.45.x) on December 24 2025, 12:26pm
Reply on December 24 2025, 4:57pm (edited at December 24 2025, 4:58pm):

yep it's output-dry. think of wet/dry mix, except with the scales being 1 and -1 rather than 0.5/0.5 or 0.1/0.9 etc. 3 Comments...

Question: Do you mind sharing a bit of insights how the spl function within JSFX operatest? Does it perform boundary checks for the channel on each sample or is there some more performant way to avoid out-of-bounds access? And also, do you have any experience on the performance hit?
Asked by capital-G (185.104.138.x) on December 23 2025, 9:16am
Reply on December 23 2025, 4:25pm:

It does have to clamp the input and convert to integer, so it does have some additional CPU use, yeah. For a very CPU-intensive JSFX, it might not make much of a difference, but for a very lightweight filter it would be significant. Comment...

Question: Will 256 channels be supported?
Asked by hihi (221.215.214.x) on December 23 2025, 5:08am
Reply on December 23 2025, 4:24pm:

No plans anytime soon, such a rare need for it and processing them will trash CPU caches, but you can use that many hardware channels and you can use multiple 128-channel tracks... Comment...

Question: Have you tried Claude Code (CLI or VSC ext)? Opus 4.5 is *really good* (could be useful for tedius/boring tasks)
Asked by Ryan (174.7.109.x) on December 23 2025, 12:58am
Reply on December 23 2025, 4:23pm:

I haven't. tedious/boring things are good for you. either you figure out ways to speed them up (scripts to accomplish repetitive tasks), or you get the practice in doing these things, improving your skills. You train for marathons by putting in lots of easy miles along with your speedwork. The biggest win of LLMs IMO is discovery of poorly documented things. Comment...

Question: How would you approach this task when an audio track has latency, but you don’t want to align other tracks to it by making them late. Instead, you want this track to align with the others by playing earlier (as if its latency were zero).
Asked by zabukowski (86.61.40.x) on December 22 2025, 5:19pm
Reply on December 23 2025, 4:20pm:

if you're not monitoring input, then you can read the media ahead of time etc. if you're monitoring input, then you have to make some sacrifices... Comment...

Question: What is your feeling towards LLM-generated JSFX/Lua scripts shared within the community? On one hand, it can make for quicker deliveries/iterations, and even provide non-developers a way to bring their ideas to reality without having to learn programming. More creative freedom! On the other hand, it can mean reliquishing control on the generated code and not being able to maintain it properly, thus becoming dependent on the AI tech stack -- which itself is built by people with no care about consequences (
Asked by Gzib (92.153.75.x) on December 22 2025, 10:47am
Reply on December 22 2025, 4:35pm: