ResonantLive Sound Archive

Equipment file · Electrodynamic horn loudspeaker

Telemegafone Type R2

Magnavox · 1920

Evidence status · documented

Identity and core specifications are documented; some historical fields remain unavailable.

The Magnavox Telemegafone Type R2 was a moving-coil horn loudspeaker with a field-coil driver and a swan-necked metal horn, sold to pair with a separate radio. Variants included the R2A, R2B and R2C.

Introduced
1920
Category
Electrodynamic horn loudspeaker
Intended use
Loud radio reception and monitoring
Production
The Magnavox Company, Oakland, California

Equipment photographs · 1

US patent 1,448,279 (1923): electrodynamic receiver, the Magnavox moving-coil driver

1 / 1 · US patent 1,448,279 (1923): electrodynamic receiver, the Magnavox moving-coil driver

US patent 1,448,279 (1923): electrodynamic receiver, the Magnavox moving-coil driver·Edwin S. Pridham & Peter L. Jensen·Public domain (US patent)

Why it mattered

  1. 01

    Among the first commercially sold moving-coil loudspeakers, the principle that became the industry standard.

  2. 02

    It bridged home radio and early monitoring and PA use, descending from the [[magnavox-telemegafone|1915 Telemegafone]].

Engineering record

Driver
Electrodynamic moving-coil unit with an 8-ohm field coil drawing about 0.6 A and a 1,700-ohm induction coil[1]
R2B horn
An 18-inch horn with a crystalline finish meant to reduce the tinny sound of smooth metal horns[2]

Original pricing

$85 (R2B) (1922)

2026 equivalent

≈ $1,690

Period US list or retail price reported by the cited source.[2]

Estimated in 2026 US dollars using the BLS CPI-U annual average for 1922 (16.8) and 334.980 for 2026, rounded to the nearest $10.[4]

Use in the field

A Type R2 Model C was used in the KFUO radio studio, St. Louis, c. 1924–27, so speakers could monitor their own voices[3]

Manuals & original documents

No authoritative manual or original document has been located for this profile.

Sources

  1. 1R2A Telemegafone (curved horn)Radiomuseum.org · reference
  2. 2R2B SpeakerRadiomuseum.org · reference
  3. 3Telemegaphone. KFUO (Magnavox), 1925Concordia Historical Institute · archive · 1925
  4. 4CPI Inflation Calculator methodology and CPI-U dataU.S. Bureau of Labor Statistics · reference · 2026

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