# Performance record: The C major Prelude, harmony only (after Bach, BWV 846): take 5, forward/reverse echo

**Performance** `perf_bwv846-take5_fwd_rev_echo` · performed 2026-10-17 14:18:18-07:00 (PDT, UTC−7) · 126.4 s · Algorithmic Performer · seed 846  
**Status:** preview only · record **UNSIGNED** (signing is open decision #33) · record hash `bdac1317881a82dd…`

## Credits

- **Music:** Johann Sebastian Bach, Prelude in C major, BWV 846, Das Wohltemperierte Klavier I (1722). Public domain.
- **Composition:** *The C major Prelude, harmony only*, by **Peter** (`compositions/bach_bwv846_prelude_progression.md`).
- **Harmonic analysis:** Mark Gotham et al., When in Rome corpus (github.com/MarkGotham/When-in-Rome), CC BY-SA 4.0.
- **Sounds:** 28 chord strike recordings by **Peter**, [musicmatter.art](https://musicmatter.art/), CC BY-SA 4.0, used 74 times (each also heard reversed).
- **Performer:** Astrid, NetComposer Algorithmic Performer (`render5_fwd_rev_echo.py`). Echo idea and filter sweep requested by Peter.

## Sounds used

| Sound | Supplier | License | Uses | Bars |
|---|---|---|---|---|
| [am7-bounce-2.flac](https://musicmatter.art/sounds/am7-bounce-2.flac) | Peter | CC BY-SA 4.0 | 2 | 9 |
| [amin-bounce-5.flac](https://musicmatter.art/sounds/amin-bounce-5.flac) | Peter | CC BY-SA 4.0 | 2 | 5 |
| [bdim7-bounce-3.flac](https://musicmatter.art/sounds/bdim7-bounce-3.flac) | Peter | CC BY-SA 4.0 | 2 | 14 |
| [c7-bounce-4.flac](https://musicmatter.art/sounds/c7-bounce-4.flac) | Peter | CC BY-SA 4.0 | 2 | 20 |
| [c7-bounce-6.flac](https://musicmatter.art/sounds/c7-bounce-6.flac) | Peter | CC BY-SA 4.0 | 2 | 32 |
| [cdim7-bounce-3.flac](https://musicmatter.art/sounds/cdim7-bounce-3.flac) | Peter | CC BY-SA 4.0 | 2 | 28 |
| [cmaj-bounce-26.flac](https://musicmatter.art/sounds/cmaj-bounce-26.flac) | Peter | CC BY-SA 4.0 | 6 | 1, 4, 35 |
| [cmaj-bounce-28.flac](https://musicmatter.art/sounds/cmaj-bounce-28.flac) | Peter | CC BY-SA 4.0 | 4 | 25, 29 |
| [cmaj-bounce-32.flac](https://musicmatter.art/sounds/cmaj-bounce-32.flac) | Peter | CC BY-SA 4.0 | 2 | 19 |
| [cmaj-bounce-34.flac](https://musicmatter.art/sounds/cmaj-bounce-34.flac) | Peter | CC BY-SA 4.0 | 2 | 15 |
| [cmaj7-bounce-6.flac](https://musicmatter.art/sounds/cmaj7-bounce-6.flac) | Peter | CC BY-SA 4.0 | 2 | 8 |
| [csus4-bounce-4.flac](https://musicmatter.art/sounds/csus4-bounce-4.flac) | Peter | CC BY-SA 4.0 | 4 (layer ×4) | 26, 30 |
| [d7-bounce-4.flac](https://musicmatter.art/sounds/d7-bounce-4.flac) | Peter | CC BY-SA 4.0 | 2 | 10 |
| [d7-bounce-6.flac](https://musicmatter.art/sounds/d7-bounce-6.flac) | Peter | CC BY-SA 4.0 | 2 | 6 |
| [dm7-bounce-1.flac](https://musicmatter.art/sounds/dm7-bounce-1.flac) | Peter | CC BY-SA 4.0 | 2 | 17 |
| [dm7-bounce-3.flac](https://musicmatter.art/sounds/dm7-bounce-3.flac) | Peter | CC BY-SA 4.0 | 4 | 2, 33 |
| [dmin-bounce-4.flac](https://musicmatter.art/sounds/dmin-bounce-4.flac) | Peter | CC BY-SA 4.0 | 2 | 13 |
| [dsharpdim7-bounce-4.flac](https://musicmatter.art/sounds/dsharpdim7-bounce-4.flac) | Peter | CC BY-SA 4.0 | 2 | 22 |
| [edim7-bounce-5.flac](https://musicmatter.art/sounds/edim7-bounce-5.flac) | Peter | CC BY-SA 4.0 | 2 | 12 |
| [fmaj7-bounce-1.flac](https://musicmatter.art/sounds/fmaj7-bounce-1.flac) | Peter | CC BY-SA 4.0 | 2 | 21 |
| [fmaj7-bounce-4.flac](https://musicmatter.art/sounds/fmaj7-bounce-4.flac) | Peter | CC BY-SA 4.0 | 2 | 16 |
| [g7-bounce-2.flac](https://musicmatter.art/sounds/g7-bounce-2.flac) | Peter | CC BY-SA 4.0 | 8 | 18, 24, 27, 31 |
| [g7-bounce-3.flac](https://musicmatter.art/sounds/g7-bounce-3.flac) | Peter | CC BY-SA 4.0 | 2 | 34 |
| [g7-bounce-6.flac](https://musicmatter.art/sounds/g7-bounce-6.flac) | Peter | CC BY-SA 4.0 | 2 | 3 |
| [gmaj-bounce-30.flac](https://musicmatter.art/sounds/gmaj-bounce-30.flac) | Peter | CC BY-SA 4.0 | 2 | 7 |
| [gmaj-bounce-32.flac](https://musicmatter.art/sounds/gmaj-bounce-32.flac) | Peter | CC BY-SA 4.0 | 2 | 11 |
| [gsharpdim7-bounce-4.flac](https://musicmatter.art/sounds/gsharpdim7-bounce-4.flac) | Peter | CC BY-SA 4.0 | 2 | 23 |
| [gsus4-bounce-3.flac](https://musicmatter.art/sounds/gsus4-bounce-3.flac) | Peter | CC BY-SA 4.0 | 4 | 26, 30 |
| **28 sounds** | | | **74** | |

No time-stretch and no pitch change. Each file's decoded audio is sample-identical to the FLAC on musicmatter.art (PCM md5 checked); sha256 values are in the record JSON.

## Hacks chain

1. **Reverse echo:** each strike also played reversed, starting 0.10 s after it and swelling to a peak 80 ms before the next strike; 6 dB under the forward voice, −3 dB shelf above 4 kHz, ducked where it would mask the next attack
2. **Reverb:** synthetic hall, generated in the script (no external IR), RT60 2.6 s, 22 ms predelay, seed 846, 40% wet (reverse voice 50%)
3. **Low-pass sweep:** 24 dB/oct, 500 Hz → 20 kHz over the first 60 s, then back down to 600 Hz by the end
4. **Tail:** 3 s fade
5. **Loudness:** two-pass linear, −14 LUFS / −1 dBTP ceiling, mp3 measured −13.9 LUFS, −1.0 dBTP

Tempo: 69 BPM, broadening over bars 33–35 (+4%, +10%, +18%). Two strikes per bar.

## Known compromises

- Bars 26, 30: Layered substitution: G7sus4 = Gsus4 + Csus4/G (no 7sus4 recording)
- Bars 28: G pedal under F#dim7 not carried (G is not a chord tone of any dim7 take)
- Bars 34: C pedal under G7 not available

## License & attribution

**CC BY-SA 4.0.** Every input is public domain or CC BY-SA 4.0, with no NC or ND inputs.

Ready to paste:

> “The C major Prelude, harmony only (after Bach, BWV 846)”, NetComposer Performance perf_bwv846-take5_fwd_rev_echo, composed by Peter after J.S. Bach (public domain), with harmonic analysis from When in Rome by Mark Gotham et al. (CC BY-SA 4.0, github.com/MarkGotham/When-in-Rome). Performed by the NetComposer Algorithmic Performer (Astrid) from 28 chord recordings by Peter (musicmatter.art, CC BY-SA 4.0). Licensed CC BY-SA 4.0, https://creativecommons.org/licenses/by-sa/4.0/

Files: `take5_fwd_rev_echo.wav` sha256 `056951cdceb3b703…` · `.mp3` sha256 `9ecc6f9e1a6e2a24…`

## Amendment

2026-10-17T19:29:52-07:00: contributor display name changed from Petrus to Peter (Peter Semmelhack) for netcomposer.art, at his request. Nothing else changed. Previous record hash `d17c38ba79ba9451…`, new `bdac1317881a82dd…`.