Ask Justin Frankel

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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: 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

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

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

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

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:

Yeah, kinda dicey to be running code that hasn't really been understood by a human. I wouldn't trust it that's for sure! Comment...

Question: what was the best financial devision you ever made?
Asked by Guzman (179.24.193.x) on December 21 2025, 7:34pm
Reply on December 21 2025, 8:04pm (edited at December 21 2025, 9:27pm):

edit: tossup between selling Nullsoft and not having kids? Comment...

Question: Are you planning to start working on a major feature for Reaper in 2026 that will be released with Reaper 8? If so, what is it? :) Unless it’s a secret or a surprise :)
Asked by Pibs (92.157.64.x) on December 21 2025, 6:06pm
Reply on December 21 2025, 8:04pm:

No real plans, we'll see what happens! 2 Comments...

Question: The computer only has a built-in sound card. Is it possible to completely use REAPER without any other plugins or software to record the sound from the computer microphone synchronously? For example, it can be used for teaching and lecture recording, since both the computer audio and microphone audio need to be captured simultaneously.
Asked by yeater (221.215.214.x) on December 21 2025, 7:11am
Reply on December 21 2025, 8:05pm:

Hmm maybe, not sure without more information on the specifics. Capturing the computer's audio output simultaneously along with a microphone might not be possible depending on the OS and hardware. Comment...

Question: Is the Windows settings shortcut on the right side of the keyboard not working? Only the left one can.
Asked by lolo (167.234.251.x) on December 19 2025, 2:50pm
Reply on December 21 2025, 12:19am:

ah yeah I guess we use VK_LWIN everywhere and never VK_RWIN, oops. Comment...

Question: In a DAW, how do you manage the audio graph based on inputs read from the main thread? I read somewhere that editing the audio graph should only be done by the audio thread. And chatGPT said to implement it by having a set of commands, I.e. AddTrack, SwitchInstrument, etc. And then send those from main thread to audio thread using a lock free queue. That seems like a lot of work though. Is there a more elegant way? How do you do it in reaper?
Asked by Edward (198.58.185.x) on December 19 2025, 10:43am
Reply on December 19 2025, 1:36pm:

You can use locks, you just need to make sure when taking them from the main thread that you don't hold them for very long! Comment...

Question: Any thoughts on plugins like Soothe2, Gullfuss, Speccraft etc.? Have you tried those?
Asked by Chris (77.23.250.x) on December 17 2025, 11:31pm
Reply on December 19 2025, 1:35pm:

Haven't tried those Comment...

Question: What's the most thoughtful gift you've ever received?
Asked by Will (184.75.221.x) on December 17 2025, 3:31pm
Reply on December 19 2025, 1:35pm:

hmm apparently nothing has stuck with me hah. Comment...

Question: In JSFX, a gate plugin with lookahead (preopen) like reagate, after the pdc report, you also compensate for the lookahead time by adding the lookahead time (in ms) to the hold slider calculation, I did this and it worked, it prevented the gate from closing prematurely before the lookahead was done. How did you do it in a compressor (reacomp which has lookahead/precomp)? Here there is no hold parameter, so should I add the lookahead time (ms) to the the release slider calculation?
Asked by Lookahead- (197.251.240.x) on December 16 2025, 6:47pm
Reply on December 16 2025, 9:36pm:

a compressor doesn't have an open/shut state... you could have the compressor use the maximum envelope value in the lookahead window (rather than the 'lookahead" envelope value), or the maximum of the current and the lookahead value, or something in between. 1 Comment...

Question: I just noticed this article posted up somewhere re: fl studio web browser   In general, what’s your opinion or feeling about the latest trend of WASM based software? Is it something that peaks your interest a bit, or not at all? Any sort of major pros or cons that you could rant or rave about?  (ps. This is not a feature request, or a Reaper question, but obviously would be cool to see Reaper loaded up in a browser one day for shi*s and giggles).   cdm.link/fl-studio-on-the-web/
Asked by dom64 (82.132.214.x) on December 16 2025, 4:35am
Reply on December 16 2025, 1:28pm:

it would be incredibly limited by the platform, so not really interesting for us. Comment...

Question: Is there a way to get vst3 param index from ParamID? because parameter change notified using ParamID.
Asked by Ruchira (175.157.137.x) on December 15 2025, 1:51pm
Reply on December 15 2025, 1:54pm:

we build an index when we load the plug-in or the plug-in says its parameters changed Comment...

Question: At dec. 5 you said: "C++ is indeed a terrible language but there are features of it that I appreciate." --> what would have been made differently in C++ to make it not terrible?
Asked by MS_from_Sweden (82.100.127.x) on December 14 2025, 7:31am
Reply on December 14 2025, 5:58pm:

Too many things to list, but there's just so much in there and so many footguns, that it's easy for people to unintentionally write completely awful code. Yes, you can write nice code using a nice subset of it, but it's hard to tell just looking at code whether it is that, without potentially digging through tons and tons of code. E.g. "sometype foo; foo++; " I have no idea what that does. does it create temporary objects and copy them around? maybe! Comment...

Question: If you had any advice for a 22 year old writting a daw from top to bottom about anything (development, life, philosophy) what would it be?
Asked by mike (71.254.197.x) on December 12 2025, 10:08pm
Reply on December 13 2025, 1:42pm:

enjoy your youth, set aside a good chunk of your time for being outside and active lol Comment...

Question: I will share my portable version with others or use it for teaching, so I will integrate some VST plugins by default. I place them in the "pluginsfx" directory, which is very convenient as they are scanned automatically by default. However, when I put CLAP plugins in, this auto-scan doesn't work. Could you make it scan CLAP plugins automatically, or is there any way to trigger a scan for them?
Asked by dear (221.215.214.x) on December 12 2025, 12:33pm
Reply on December 12 2025, 1:40pm:

If you put them in UserPlugins/FX, it will search for .clap too (and VST -- you should ideally use that for both!). 1 Comment...

Question: Are you 'following' Gavin Newsom?
Asked by wasereb4 (95.91.78.x) on December 11 2025, 5:21am
Reply on December 11 2025, 1:34pm:

I'm familiar with him, but don't follow on social media (avoid social media), not much of a fan but obviously better than some of the alternatives. Comment...

Question: I'm a musician trying to make a webamp player for my website. I checked out your music on 1014 and it's dope! If you were to make winamp player in 2025 how would you do it?
Asked by Himi (49.43.90.x) on December 10 2025, 10:13pm
Reply on December 11 2025, 1:52am:

Hmm feel free to rip off my javascript! In fact maybe I'll make a template bit of javascript/html that you can embed in any web page for similar function, any interest in that? 1 Comment...

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