What we know about the measurement:

Part Express DIY Copperhead is a passive bookshelves that cost around 100 USD for a pair.

  • Quality of the measurement data is high.
  • Origin of the data is ErinsAudioCorner.
  • Format of the data is generated by a Klippel NFS .
  • Sensitivity: 76.6dB (avg. 100Hz-1kHz for 2.83V estimated at 1m)
  • -3dB (resp. -6db) point v.s. reference is at 98.1Hz (resp. 82.0Hz).
  • Reference level is normalised to 0.1dB computed over the frequency range [300.0Hz, 5000.0Hz].
  • Frequency deviation is 4.4dB over the same frequency range.
  • Directivity
    • Horizontal directivity is (-60.0°, 60.0°) between 1kHz and 10kHz. Angle computed for +/-6dB.
    • Vertical directivity is (-60.0°, 60.0°) between 1kHz and 10kHz. Angle computed for +/-6dB.
  • Tonality (Preference) Score
    • Tonality (Preference) Score is 2.13 and would be 5.38 with a perfect subwoofer.
      • Details: NBD: ON 0.636, LW 0.589, SP 0.589, PIR 0.579; SM: SP0.74, PIR0.436; LFQ 0.533, LFX 82Hz
    • Tonality (Preference) Score is 4.04 with an EQ and would be 7.11 with a perfect subwoofer and the same EQ.
      • Details: NBD: ON 0.468, LW 0.417, SP 0.486, PIR 0.416; SM: SP0.861, PIR0.793; LFQ 0.533, LFX 74Hz
  • Link to Original review.
Part Express DIY Copperhead
AutomaticEQ (IIR)
Set preamp gain to: -1.1dB.
Type Freq Q Gain
3 166.0 1.13 -4.68
3 172.0 0.26 2.39
3 2168.0 3.0 -2.14
3 6144.0 2.98 2.99
3 9989.0 0.25 -2.66
3 11882.0 2.16 2.99
3 16239.0 0.96 -8.35
Download

These EQ optimise the Harman score and is a good start for far field listening like in your living room.

Part Express DIY Copperhead filters_auto_eq

AutomaticEQ

Part Express DIY Copperhead filters_eq_full

Target v.s. EQ

Part Express DIY Copperhead
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 0.5
3 160.0 2.14 -0.5
3 250.0 2.14 -0.25
3 400.0 2.14 0.0
3 630.0 2.14 0.0
3 1000.0 2.14 0.25
3 1600.0 2.14 -0.25
3 2500.0 2.14 0.0
3 4000.0 2.14 -0.25
3 6300.0 2.14 0.0
3 10000.0 2.14 -0.25
3 16000.0 2.14 -1.0
Download

These EQ is designed for a 15 bands graphical EQ.

Part Express DIY Copperhead
Graphic EQ 31 bands
Set preamp gain to: -0.8dB.
Type Freq Q Gain
3 20.0 4.32 0.0
3 25.0 4.32 0.5
3 31.0 4.32 0.5
3 40.0 4.32 0.5
3 50.0 4.32 0.5
3 63.0 4.32 0.5
3 80.0 4.32 0.5
3 100.0 4.32 0.5
3 125.0 4.32 -0.25
3 160.0 4.32 -0.5
3 200.0 4.32 -0.5
3 250.0 4.32 -0.25
3 315.0 4.32 0.0
3 400.0 4.32 0.0
3 500.0 4.32 0.0
3 630.0 4.32 0.0
3 800.0 4.32 0.0
3 1000.0 4.32 0.0
3 1250.0 4.32 -0.25
3 1600.0 4.32 -0.25
3 2000.0 4.32 -0.5
3 2500.0 4.32 -0.25
3 3150.0 4.32 -0.5
3 4000.0 4.32 -0.25
3 5000.0 4.32 -0.5
3 6300.0 4.32 -0.25
3 8000.0 4.32 -1.0
3 10000.0 4.32 -0.25
3 12000.0 4.32 -0.25
3 16000.0 4.32 -1.25
3 20000.0 4.32 0.0
Download

These EQ is designed for a 31 bands graphical EQ.

Part Express DIY Copperhead: comparison between EQs
Part Express DIY Copperhead

Comparison betweens various EQs

Part Express DIY Copperhead

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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