# OpenScore String Quartets ![Category](https://img.shields.io/badge/Category-Reasoning-1f6feb) ![Metric](https://img.shields.io/badge/Metric-1%20-%20OMR--NED-2da44e) ![Saturation](https://img.shields.io/badge/Saturation-Medium-d29922) ![Created](https://img.shields.io/badge/Created-2023-555) [![Paper](https://img.shields.io/badge/Paper-ACM%20DLfM%202023-b31b1b)](https://doi.org/10.1145/3625135.3625155) > **Quick answer:** OpenScore String Quartets is a benchmark built on the OpenScore String Quartet Corpus (Gotham, Redbond, Bower & Jonas, 2023) that tests optical music recognition (OMR) — a model's ability to read a musical score image and transcribe it accurately. Scores are reported as 1 minus the OMR normalized edit distance (OMR-NED), so higher is better. GPT-6 Astra scores 0.84, versus 0.19 for GPT-5.6 Sol. ## At a Glance **What it tests:** Whether a multimodal model can visually parse a string quartet score (an image of sheet music) and transcribe its notation accurately — pitches, rhythms, and structure across four instrumental parts. **Why it matters:** Optical music recognition is a specialized visual-reasoning task combining fine-grained image understanding with structured symbolic output. Strong performance signals genuine visual precision, not just pattern-matching on common image types — a distinct capability from general OCR or document understanding. **Known limitations:** Narrow domain (classical string quartet scores specifically); the corpus and evaluation methodology were originally built for musicology research, not AI benchmarking, so task framing for LLM evaluation is comparatively new. ## What OpenScore String Quartets Measures The OpenScore String Quartet Corpus (Gotham et al., 2023) is a large, high-quality digital corpus of string quartet scores originally built for computational musicology research. Repurposed as an AI benchmark, it tests whether a model can take an image of a musical score and produce an accurate machine-readable transcription — a task requiring precise visual parsing of dense, structured notation across multiple simultaneous instrumental parts. Performance is measured as 1 minus the OMR normalized edit distance (OMR-NED) between the model's transcription and the ground-truth score — a standard optical-music-recognition metric that penalizes insertions, deletions, and substitutions relative to the correct transcription, normalized by score length. A score of 1.0 would represent a perfect transcription; scores near 0 indicate the transcription bears little resemblance to the source. ## Benchmark Specifications | Field | Value | |---|---| | Task category | Reasoning / Multimodal | | Metric | 1 - OMR-NED (normalized edit distance, higher = better) | | Saturation | Medium — meaningful spread between frontier models | | Created by | Mark R. H. Gotham, Maureen Redbond, Bruno Bower, Peter Jonas | | Source paper | [Gotham et al., ACM DLfM 2023](https://doi.org/10.1145/3625135.3625155) | ## How OpenScore String Quartets Is Scored The score is computed as 1 minus the normalized edit distance between the model's transcription output and the ground-truth score encoding. This means the metric behaves like an accuracy score on a 0-1 scale, where 1.0 is a perfect transcription and lower values reflect proportionally more transcription errors relative to the total content of the score. ## State-of-the-Art Results | Rank | Model | Score | Source | Date | |---|---|---|---|---| | 1 | [GPT-6 Astra](/models/openai/gpt-6-astra) | 0.84 | [OpenAI: GPT-6 Astra](https://openai.com/index/gpt-6-astra/) | 2026-09 | | 2 | [GPT-5.6 Sol](/models/openai/gpt-5-6-sol) | 0.19 | [OpenAI: GPT-6 Astra](https://openai.com/index/gpt-6-astra/) | 2026-09 | *Scores sourced from OpenAI's GPT-6 Astra announcement (September 2026), citing the OpenScore String Quartet Corpus (Gotham et al. 2023).* ## OpenScore String Quartets on Benchgen > No Benchgen results yet — [be the first to run OpenScore String Quartets](/benchmarks/gotham-et-al/openscore-string-quartets). ## OpenScore String Quartets vs Other Benchmarks | Benchmark | What it tests | Saturation | |---|---|---| | **OpenScore String Quartets** | Optical music recognition (score transcription) | Medium | | [ScreenSpot-Pro](/benchmarks/screenspot-pro) | Visual grounding for GUI elements | Low | OpenScore String Quartets is a niche but genuinely differentiating visual-precision test — unlike most multimodal benchmarks, it demands exact structured transcription rather than natural-language description. ## Run OpenScore String Quartets on Your Model Benchgen lets teams benchmark visual transcription accuracy across model versions, tracking regressions in fine-grained multimodal parsing that a single vendor snapshot would miss. ## Related Models & Benchmarks - Top performers: [GPT-6 Astra](/models/openai/gpt-6-astra) - Related benchmarks: [ScreenSpot-Pro](/benchmarks/screenspot-pro) ## Frequently Asked Questions

What is OpenScore String Quartets?

A benchmark testing AI optical music recognition on string quartet scores from the OpenScore String Quartet Corpus, scored as 1 minus normalized edit distance (OMR-NED).

What does a good score look like?

Scores close to 1.0 indicate near-perfect transcription. As of September 2026, GPT-6 Astra leads at 0.84, a large jump from GPT-5.6 Sol's 0.19.

Who created OpenScore String Quartets?

The underlying corpus was created by Mark R. H. Gotham, Maureen Redbond, Bruno Bower, and Peter Jonas, published at ACM DLfM 2023.

--- *Benchmark definition paraphrased from Gotham et al. 2023. State-of-the-art scores sourced from OpenAI's GPT-6 Astra announcement. Last updated 2026-09-07.*

OpenScore String Quartets — Results

OpenScore String Quartets — Phases

OpenScore String Quartets