Engrove Audio Tools · Tonearm database reference
Ortofon RMG-309
Ortofon RMG-309 tonearm reference data for cartridge matching, effective mass, effective length and setup context.
Reference specifications
| Manufacturer | Ortofon |
|---|---|
| Model | RMG-309 |
| Effective mass | 28 g |
| Effective length | 321 mm |
| Headshell connector | sme_universal |
| Cartridge weight range | 20 g–40 g |
Setup context
Use this tonearm reference with the Tonearm Match Lab and Tonearm Geometry Lab to plan cartridge matching and alignment. The key setup inputs are effective mass and effective length.
Reference data is best-effort and should be checked against manufacturer documentation before critical setup decisions.
Related Ortofon tonearms
Model-specific cartridge matching scenarios
Its stored effective mass is 28 g, which places the arm in the high-mass range for matching work. The 321 mm effective length is relevant to alignment geometry and mounting-distance decisions. The database records a sme_universal headshell interface. Stored cartridge-weight support is 20–40 g.
| Reference cartridge case | Cartridge mass / compliance | Estimated total mass | Calculated resonance |
|---|---|---|---|
| Low-compliance MC example | 8.5 g / 8 CU | 37 g | 9.25 Hz — inside the usual 8–12 Hz setup window |
| Medium-compliance example | 7 g / 15 CU | 35.5 g | 6.9 Hz — below the usual 8–12 Hz setup window |
| High-compliance MM example | 6.5 g / 25 CU | 35 g | 5.38 Hz — below the usual 8–12 Hz setup window |
Scenarios are deliberately fixed reference cases so visitors can compare this tonearm's 28 g effective mass with different compliance classes. Replace them with the actual cartridge values in Tonearm Match Lab before making a setup decision.
Data provenance
Research match: src/data/audio/v3/runtime/tonearms.index.json.