MTX RTX4BTs picture


RTX 16,5cm 6.5” 4Ω 125W RMS High Efficiency Midrange


The MTX RTX654 midrange is a 16.5cm (6.5 ”) high output loudspeaker. With little power, it reproduces a lot of sound. It handles 125W RMS with an efficiency over 97dB. It is intended for SQL installations and open door sound systems. The sound is very powerful and very live. It shines with a striking realism, its softness and its exceptional musicality. Despite its very high efficiency, it is never brutal or aggressive.
Its large 38mm coil, its phase plug to fight against standing waves, its extra large magnetic structure (Ø113mm), its fabric suspension and its pressed paper cone are all assets that help with the sound quality and transducer performance.
Please note, the RTX654 is sold by piece. You therefore need two RTX654 to do right-left stereo. You must also use two MTX RTX2BTs or RTX4BTs tweeters for the treble.


  • Exceptional sound quality with an incredible musicality
  • 38mm 1.5” giant voice coil for more power handling
  • 115mm extra large strontium magnet for a better cone control and more power handling
  • Compressed paper cone for more efficiency, softness and high quality sound
  • Treated Cloth edge suspension for a better efficiency
  • Highly detailed midrange
  • Good bass response
  • Easy to install - Fits into the original 16,5cm 6.5” cut outs (Ø145mm)
  • Sold by piece - You need two RTX654 for a stereo system
  • Design to play with MTX RTX2BTs or RTX4BTs tweeters
  • Design to play with MTX TR275 TX2275 TR450 TX2450 TX480D RFL4120 RFM5300 amplifiers


  • High efficiency midrange
  • Diameter: 16,5cm 6.5”
  • Peak Power: 500W
  • RMS Power: 125W
  • Sensitivity: 97,2dB/2,83v/1m
  • Impedance: 4Ω
  • Freq. response: 150Hz - 10000Hz
  • Mounting Depth: 56,6mm
  • Recommended x-over: >150Hz
  • Fs: 145Hz


  • Re : 3,04Ω
  • Le : 0,205mH
  • L2 : 0,238mH
  • R2 : 2,03Ω
  • Cmes : 315,77μF
  • Res : 54,31Ω
  • Fs : 145,3Hz
  • Mms : 11,501g
  • Mmd : 9,773g
  • Rms : 0,671 Kg/s
  • Cms : 0,104mm/N
  • Kms : 9,58N/mm
  • Bl : 6,035N/A
  • Qms : 15,652
  • Qes : 0,875
  • Qts : 0,829
  • Vas : 2,6027 liters
  • Sd : 132,73cm2
  • Lnom : 97,2/2,83V/1m

Recommended efficient associations

Designed to play with RTX2BTs or RTX4BTs midranges

MTX TX2450 picture

Recommended amplifiers: MTX TR275 TX2275 TR450 TX2450 TX480D RFL4120 RFM5300

MTX TX2450 picture


MTX wants you to enjoy your hearing for a long time. Excessive exposure to loud volumes can damage your hearing. The United States Department of Labor recommends not exceeding the following recommendations:
90db : maximum 8 hours / day
92dB : maximum 6 hours / day
95db : maximum 4 hours / day
97db : maximum 3 hours / day
100db : maximum 2 hours / day
102db : maximum 90 minutes / day
105db : maximum 60 minutes / day
110db : maximum 30 minutes / day
115db : maximum less than 15 minutes / day
120db : immediate danger, 0 minutes / day



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