Birmingham 1275

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back side of the Birmingham 1275
front of the Birmingham 1275
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ToneSpeak's seven year warranty logo
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Made-in-Minnesota logo
ISO 9001-2015 certification logo
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The Birmingham 1275 by ToneSpeak captures the essence of '60s and '70s British rock, offering a rich, harmonically complex tone that remains balanced across the frequency range. With a punchy, well-defined low end, a warm and expansive midrange, and a high end that soars with articulation, this speaker brings both power and musicality to your rig.

Featuring a premium Kurt Müller cone, a 50 oz. ferrite magnet, and a 1.75-inch copper voice coil with a Nomex former, the Birmingham 1275 is built for both clarity and grit. Designed to handle 75 watts with a sensitivity of 100 dB SPL, this speaker ensures powerful projection and a bold presence in any mix.

Key Features:

  • 12-inch (305 mm), 75-Watt power handling at 8 Ω impedance
  • 100 dB SPL sensitivity for exceptional projection
  • Kurt Müller cone for a rich, dynamic British tone
  • 1.75-inch copper voice coil with Nomex former for durability
  • 50 oz. ferrite magnet for strong, balanced sound
  • Defined low end, warm mids, and articulate highs

For players who crave a speaker with punch, grit, and clarity, the Birmingham 1275 delivers vintage British rock tone with modern reliability.

sensitivity & impedance curves

Input: 2.83 volts measured at 1 Meter

frequency and impedance response graph of the ToneSpeak Birmingham 1275
0 deg response
30 deg response
60 deg response
impedance

general specifications

Nominal Diameter (in & mm)12" (305 mm)
Nominal Impedance (Z) (Ω)
Rated Power IEC268-5 (W)75
Program Power (W)
Magnet Weight (g)1417
Voice Coil Diameter (mm)44
Sensitivity (dB SPL)100
Frequency Range (Hz)80 - 5000

small signal parameters

Resonant Frequency (Fs) (Hz) +/- 15%93
DC Resistance (Re) (Ω)7.1
Voice Coil Inductance (Le) (mH)0.37
Moving Mass (Mms) (gm)29.9
Suspension Compliance (Cms) (mm/N)0.1
Motor Force Factor (BL) (T•M)13.09
Mechanical Q Factor (Qms)20.81
Electrical Q Factor (Qes)0.71
Total Q Factor (Qts)0.69
Compliance Equivalent Volume (Vas) (L)40.2
Surface Area of Diaphragm (Sd) (cm²)539.1

material description

Basket TypeStamped steel with black powder coat painting
Magnet MaterialFerrite
Cone Body MaterialFelted paper
Cone Surround MaterialFelted paper with damping edge treatment
Dust Cap MaterialOpen cloth
Spider MaterialCotton
Voice Coil Wire MaterialCopper
Voice Coil Former MaterialNomex
Voice Coil Winding StyleSingle Layer

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