What we know about the measurement:

KEF Reference 4C is a passive center that cost around 7500 USD

  • Quality of the measurement data is high.
  • Origin of the data is ASR.
  • Format of the data is generated by a Klippel NFS .
  • Sensitivity: 90.9dB (avg. 100Hz-1kHz for 2.83V measured at 1m).
  • -3dB (resp. -6db) point v.s. reference is at 67.4Hz (resp. 48.3Hz).
  • Reference level is normalised to 0.2dB computed over the frequency range [300.0Hz, 5000.0Hz].
  • Frequency deviation is 2.6dB over the same frequency range.
  • Directivity
    • Horizontal directivity is (-50.0°, 50.0°) between 1kHz and 10kHz. Angle computed for +/-6dB.
    • Vertical directivity is (-40.0°, 50.0°) between 1kHz and 10kHz. Angle computed for +/-6dB.
  • Tonality (Preference) Score
    • Tonality (Preference) Score is 5.89 and would be 7.3 with a perfect subwoofer.
      • Details: NBD: ON 0.551, LW 0.456, SP 0.326, PIR 0.328; SM: SP0.965, PIR0.85; LFQ 1.447, LFX 30Hz
    • Tonality (Preference) Score is 6.99 with an EQ and would be 8.31 with a perfect subwoofer and the same EQ.
      • Details: NBD: ON 0.379, LW 0.286, SP 0.274, PIR 0.21; SM: SP0.971, PIR0.949; LFQ 1.447, LFX 29Hz
  • Vertical measurement
  • Link to Original review.
  • Link to original Review: white_paper review. .
KEF Reference 4C
AutomaticEQ (IIR)
Set preamp gain to: -3.0dB.
Type Freq Q Gain
5 73.0 1.27 2.99
3 366.0 2.73 1.36
3 432.0 2.96 -0.79
3 1141.0 2.9 2.46
3 1491.0 2.94 -1.84
3 1948.0 1.89 1.13
3 3676.0 2.91 -0.96
3 6069.0 2.99 -1.32
3 13537.0 0.62 2.18
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These EQ optimise the Harman score and is a good start for far field listening like in your living room.

KEF Reference 4C filters_auto_eq

AutomaticEQ

KEF Reference 4C filters_eq_full

Target v.s. EQ

KEF Reference 4C
Graphic EQ 15 bands
Set preamp gain to: -0.7dB.
Type Freq Q Gain
3 25.0 2.14 0.5
3 40.0 2.14 0.5
3 63.0 2.14 0.5
3 100.0 2.14 0.25
3 160.0 2.14 0.0
3 250.0 2.14 0.0
3 400.0 2.14 0.25
3 630.0 2.14 0.25
3 1000.0 2.14 0.25
3 1600.0 2.14 0.0
3 2500.0 2.14 0.0
3 4000.0 2.14 0.0
3 6300.0 2.14 0.0
3 10000.0 2.14 0.25
3 16000.0 2.14 0.5
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These EQ is designed for a 15 bands graphical EQ.

KEF Reference 4C
Graphic EQ 31 bands
Set preamp gain to: -0.5dB.
Type Freq Q Gain
3 20.0 4.32 0.0
3 25.0 4.32 0.25
3 31.0 4.32 0.25
3 40.0 4.32 0.25
3 50.0 4.32 0.25
3 63.0 4.32 0.25
3 80.0 4.32 0.25
3 100.0 4.32 0.0
3 125.0 4.32 0.0
3 160.0 4.32 0.0
3 200.0 4.32 0.0
3 250.0 4.32 0.0
3 315.0 4.32 0.25
3 400.0 4.32 0.25
3 500.0 4.32 0.0
3 630.0 4.32 0.25
3 800.0 4.32 0.0
3 1000.0 4.32 0.25
3 1250.0 4.32 0.25
3 1600.0 4.32 0.0
3 2000.0 4.32 0.0
3 2500.0 4.32 0.0
3 3150.0 4.32 0.0
3 4000.0 4.32 0.0
3 5000.0 4.32 0.0
3 6300.0 4.32 0.0
3 8000.0 4.32 0.25
3 10000.0 4.32 0.25
3 12000.0 4.32 0.25
3 16000.0 4.32 0.5
3 20000.0 4.32 0.0
Download

These EQ is designed for a 31 bands graphical EQ.

KEF Reference 4C: comparison between EQs
KEF Reference 4C

Comparison betweens various EQs

KEF Reference 4C

Improvements made by EQ

Frequency Frequency with EQ
Frequency Frequency with EQ
Frequency Frequency with EQ
Frequency Frequency with EQ
Frequency Frequency with EQ
Frequency Frequency with EQ
Frequency Frequency with EQ
Frequency Frequency with EQ
Frequency Frequency with EQ
Frequency Frequency with EQ
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