### 1. Graduation Instrument
| Build Year | 2008 |
| Owner | Halldór Úlfarsson |
| User | Max Lilja (FI) |
| Location | Finland |
| Soundbox | Halldór Úlfarsson (tutored by Kari Nieminen) |
| Electronics | Jonte Knif |
| Notes | Graduation instrument, TAIK / Aalto University. |
### 2. Hildur Guðnadóttir Instrument — Prototype
| Build Year | 2012 |
| Owner/User | Hildur Guðnadóttir (IS) |
| Location | Germany |
| Soundbox | Halldór Úlfarsson |
| Electronics | Halldór Úlfarsson |
| Notes | Experimental prototype exploring the inclusion of sympathetic strings. |
### 3. Hildur Guðnadóttir Instrument — Refined
| Build Year | 2014 |
| Owner/User | Hildur Guðnadóttir (IS) |
| Location | Germany |
| Soundbox | Jóhann Gunnarsson |
| Electronics | Halldór Úlfarsson and Christian Zollner |
| Notes | Refined sympathetic-strings version. |
### 4. The Sisters — Instrument A
| Build Year | 2018 |
| Owner | Prof. Thor Magnusson / Emute Lab, University of Sussex |
| Location | United Kingdom |
| Soundbox | Halldór Úlfarsson |
| Electronics | Halldór Úlfarsson and Orfeas Moraitis |
### 5. The Sisters — Instrument B
| Build Year | 2018 |
| Owner | Davíð Brynjar Franzson (in care) |
| User | Constantine Skourlis (GR); Konstantinos Chinis (GR) |
| Location | Los Angeles, USA |
| Soundbox | Halldór Úlfarsson |
| Electronics | Halldór Úlfarsson and Orfeas Moraitis |
### 6. ACE Funded Instrument
| Build Year | 2020 |
| Owner | Halldór Úlfarsson |
| User | Scott McLaughlin |
| Location | Athens, Greece |
| Soundbox | Konstantinos Tsopelas (GR) |
| Electronics | Orfeas Moraitis |
| Notes | Funded by Arts Council England (ACE). In residence at the University of Leeds with Prof. Scott McLaughlin, 2022–23. |
### 8. IIL Research Instrument
| Build Year | 2022 |
| Owner | Intelligent Instruments Lab |
| User | Eydís Kvaran (IS) |
| Location | Iceland |
| Soundbox | Halldór Úlfarsson |
| Electronics | Halldór Úlfarsson (Bela powered) |
### 9. Adam Schoenberg Concerto Instrument
| Build Year | 2021 |
| Owner | Adam Schoenberg / Occidental College, Pasadena |
| User | Adam Schoenberg; Yves Dhar (associated soloist) |
| Location | Los Angeles, USA |
| Soundbox | Konstantinos Tsopelas (GR) |
| Electronics | Orfeas Moraitis |
| Notes | Associated work: Automata for halldorophone and cello. |
### 10. Konstantinos Chinis Instrument
| Build Year | 2022 (estimated) |
| Owner/User | Konstantinos Chinis (GR) |
| Location | Athens, Greece |
| Soundbox | Konstantinos Tsopelas (GR) |
| Electronics | Orfeas Moraitis |
### 11. Athens Research Instrument
| Build Year | 2023 (estimated) |
| Owner | Halldór Úlfarsson |
| User | Thanos Polymeneas |
| Location | University of Athens, Greece |
| Soundbox | Konstantinos Tsopelas (GR) |
| Electronics | Orfeas Moraitis |
| Notes | Third in the Tækniþróunarsjóður series. Research model housed at the University of Athens. |
### 12. Double Speaker Instrument — EMS
| Build Year | 2023 (estimated) |
| Owner | Halldór Úlfarsson |
| User | Elektronmusikstudion (EMS) |
| Location | Athens, Greece |
| Soundbox | Konstantinos Tsopelas (GR) |
| Electronics | Orfeas Moraitis |
| Notes | Part of the EMS Residency Technology Development Fund series. |
### 13. Double Speaker Instrument — Cardiff
| Build Year | 2023 (estimated) |
| Owner/User | Leon West |
| Location | Cardiff, Wales |
| Soundbox | Konstantinos Tsopelas (GR) |
| Electronics | Orfeas Moraitis |
### 14. Double Speaker Instrument — Hildur Guðnadóttir
| Build Year | 2023 |
| Owner/User | Hildur Guðnadóttir |
| Location | Germany |
| Soundbox | Konstantinos Tsopelas (GR) |
| Electronics | Orfeas Moraitis |
### 16. Luis Resto Instrument
| Build Year | 2024 |
| Owner/User | Luis Resto |
| Location | USA |
| Soundbox | Konstantinos Tsopelas (GR) |
| Electronics | Orfeas Moraitis |
### 17. Killick Hinds Instrument
| Build Year | 2024 |
| Owner/User | Killick Hinds |
| Location | USA |
| Soundbox | Konstantinos Tsopelas (GR) |
| Electronics | Orfeas Moraitis |
## Catalogue of Halldorophones
This catalogue excludes early experiments that explored different instrument typologies as a platform for the feedback-string method.
Maintained by Halldór Úlfarsson. Last updated 10 May 2025. Corrections or additions: [halldorophone@gmail.com](mailto:halldorophone@gmail.com)
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## Instruments