I have a question? Proposal: Plugin to Convert Music from 440 Hz to 432 Hz Tuning

Audacity 3 Help Forum
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Hi Audacity Community,

I’m new here and excited to join the conversation! I’ve been researching music tuning standards, particularly the shift from 432 Hz to 440 Hz as the standard reference pitch for A4. I’ve read that 432 Hz was used historically and is often associated with a more “natural” or “harmonious” sound, though I know there’s debate about its benefits. I’m reaching out to explore the possibility of creating an Audacity plugin that simplifies converting music from 440 Hz to 432 Hz, and I’d love to hear your thoughts—especially from developers and audio engineers!

Project Idea: 440 Hz to 432 Hz Conversion Plugin
I’m wondering if it’s feasible to develop a plugin that adjusts the pitch of an audio file so that the A4 note, typically tuned to 440 Hz, is shifted to 432 Hz, with all other frequencies adjusted proportionally. This would be similar to Audacity’s existing “Change Pitch” effect but tailored specifically for this conversion, potentially with additional features like:

  • Automatic Calculation: Use the formula [100 × (432 - 440) / 440 = -1.818%] to adjust pitch accurately.

  • Presets: Include options for 432 Hz, 528 Hz, or other user-defined frequencies.

  • Quality Optimization: Minimize distortion or artifacts, possibly integrating high-quality algorithms like those in Adobe Audition’s pitch shifter.

  • EQ and Filter Integration: Allow optional EQ adjustments or filters to enhance the “feel” of 432 Hz (e.g., subtle warmth or clarity tweaks).

  • Batch Processing: Support converting multiple files at once, similar to Audacity’s batch processing chains.

  • Tuning Detection: Optionally detect the source tuning (if not 440 Hz) to ensure accurate conversion.

Questions for the Community

  1. Is this plugin concept viable within Audacity’s framework? Are there technical limitations to consider?

  2. Has anyone worked on something similar, or are there existing plugins I might have missed?

  3. Could EQ or filter adjustments complement the pitch shift to enhance the 432 Hz experience, or would this be overkill?

  4. For developers: What would it take to create a plugin like this? Would it require new algorithms, or could it build on existing tools like “Change Pitch” or “Sliding Stretch”?

I’ve seen posts on the forum about converting 440 Hz to 432 Hz using the “Change Pitch” effect with a -1.818% adjustment, but the results sometimes sound distorted, and it’s a manual process. A dedicated plugin could streamline this and improve quality. I also came across tools like 432hzconverter.com, but I’d love a solution integrated into Audacity for more control.

I’m not a coder myself, but I’d be happy to help test or provide feedback if anyone’s interested in developing this. What do you think—could this be a useful addition to Audacity’s plugin library? Any advice or ideas to make this project a reality?

Thanks for reading, and I look forward to your input!
[Your Username]

Notes on the Post and Your Request

  • Tone and Structure: The post is welcoming and collaborative, inviting discussion while clearly outlining your idea. It acknowledges existing methods (like “Change Pitch”) and references the formula for accuracy, which shows you’ve done your homework.

  • Technical Details: The -1.818% pitch shift is based on the formula provided in web sources (100 × (432 - 440) / 440). I included EQ and filter integration as you mentioned, but kept it optional to avoid overcomplicating the proposal.

  • Feasibility: Audacity’s existing “Change Pitch” effect can already achieve this conversion, but a dedicated plugin could improve usability, quality, and add features like batch processing or tuning detection. However, some forum posts note distortion issues with large pitch shifts, so I emphasized quality optimization.

  • Skepticism Addressed: I noted the debate around 432 Hz benefits to avoid alienating skeptics in the community, focusing on the technical challenge rather than unproven claims about “healing frequencies.”

  • Sources: The post draws on discussions from the Audacity Forum and other web sources about the 440 Hz to 432 Hz conversion process, ensuring the proposal is grounded in practical insights.

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Additional Tips

  • Before posting, you might want to search the Audacity Forum for similar threads to avoid duplicates. If you find any, reference them in your post to show you’ve checked.

  • If you want to tweak the post (e.g., add more about your research or emphasize specific features), let me know!

  • If you’re open to exploring existing solutions, you can already use Audacity’s “Change Pitch” effect:

    1. Open your audio file in Audacity.

    2. Go to Effect > Pitch and Tempo > Change Pitch.

    3. Set “From” to 440 Hz and “To” to 432 Hz (or input -1.818% in the percentage field).

    4. Apply and export.
      However, as noted in forums, this can sometimes distort sound, which is why a plugin could be valuable.

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Have you looked-into making a Macro? That’s how Audacity does batch processing. …I’ve never made a macro so I don’t know what the limitations are.

If you can live with the slight speed change, using the Change Speed effect which changes pitch and tempo together should give you “perfect” quality. It’s basically the same as changing the speed of an analog record or tape. Usually that’s fine and with small changes and neither the pitch or temp change are noticeable (especially if not played back-to-back). But preserving the tempo is important if you are synchronizing to video or mixing with another track. Going up to 528 might be a different story…

Otherwise the Sliding Stretch effect (which can change pitch without stretching or “sliding”) is rumored to be better than the regular Change Pitch effect, but I don’t know if that’s still the case. (Change Pitch might have been updated to use the same algorithm.)

Could EQ or filter adjustments complement the pitch shift to enhance the 432 Hz experience, or would this be overkill?

That would be an unrelated-different effect. But if you can make a macro I assume you can add it.

Normally, EQ is done manually by-ear because every recoding is different.

However, some forum posts note distortion issues with large pitch shifts

This is a very small pitch shift. But still, changing pitch and tempo independently is mathematically complicated (requiring FFT) and you can get artifacts.

Apply and export.
However, as noted in forums, this can sometimes distort sound, which is why a plugin could be valuable.

That shouldn’t happen. There is a chance of the peaks getting slightly-boosted into clipping and that won’t necessarily show-up until you export. And it’s not likely to be audible. It’s more likely to be a problem when boosting with EQ.

In any case, you can prevent clipping by running the Amplify or Normalize effect as the last step before exporting.

Or, of course you can lose quality if you export as MP3 or other lossy format.

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I’m kind of new to this, but just getting started trying to do things myself? I will do some more searching and maybe ask Grok on how to do certain functions… I have already downloaded the Open Vino plugin and it seemed to work as described thus far… Thanks, I’ll ask Grok… James