3. Filters & Slope

EQs are built around filter circuits which allow some frequencies to pass and reject others. You might well have noticed in the diagram that the response the other side of the centre or ‘cutoff’ frequency does not just drop to zero instantly, but gradually decreases. This is because it is not possible to build real-time filters that are infinitely steep, and the resulting shape is called the ‘slope’ of the filter, measured in dB per octave. So for example, a 6dB per octave filter’s slope will reduce or increase gain by 6dB for every doubling of frequency.

Frequency response of a typical shelving EQ.

Your Contacts

Best rated products

  1. DBX 215s

    DBX 215s

    In stock
    €117
    £103.14
  2. Behringer DCX2496 Ultradrive Pro

    Behringer DCX2496 Ultrad­rive Pro

    In stock
    €205
    £180.71
  3. Behringer DEQ2496 Ultra-Curve Pro

    Behringer DEQ2496 Ultra-Curve Pro

    In stock
    €235
    £207.16
  4. the t.racks DS 2/4

    the t.racks DS 2/4

    In stock
    €173
    £152.50
  5. DBX 231s

    DBX 231s

    In stock
    €135
    £119.01
  6. Behringer FBQ800

    Behringer FBQ800

    In stock
    €42
    £37.02
  7. Behringer DEQ2496 Ultra-Curve Bundle
    BUNDLE

    Behringer DEQ2496 Ultra-Curve Bundle

    In stock
    €277
    £244.18
  8. Behringer DCX2496 Ultradrive Pro B-Stock
    B-STOCK

    Behringer DCX2496 Ultrad­rive Pro B-Stock

    In stock
    €190
    £167.49
  9. DBX 1231

    DBX 1231

    In stock
    €307
    £270.63
  10. Behringer DEQ2496 Ultra-Curve Pr B-Stock
    B-STOCK

    Behringer DEQ2496 Ultra-Curve Pr B-Stock

    In stock
    €199
    £175.42
  11. Behringer FBQ1502HD Ultragraph Pro

    Behringer FBQ1502HD Ultra­graph Pro

    In stock
    €85
    £74.93
  12. Waves Gold

    Waves Gold

    Download license
    €295
    £260.05

Top Brands

  • Golden Age Project
  • IGS Audio
  • API Audio
  • Eventide
  • AMS Neve
  • Positive Grid
  • Bettermaker
  • IK Multimedia
  • Tube-Tech
  • FabFilter
  • Celemony
  • Elysia

Most popular products

  1. Behringer DCX2496 Ultradrive Pro

    Behringer DCX2496 Ultrad­rive Pro

    In stock
    €205
    £180.71
  2. Behringer DEQ2496 Ultra-Curve Pro

    Behringer DEQ2496 Ultra-Curve Pro

    In stock
    €235
    £207.16
  3. Boss EQ-200 Graphic Eq

    Boss EQ-200 Graphic Eq

    In stock
    €249
    £219.50
  4. Klark Teknik EQP-KT

    Klark Teknik EQP-KT

    In stock
    €209
    £184.24
  5. Softube Console 1 Mk 2

    Softube Con­sole 1 Mk 2

    In stock
    €389
    £342.91
  6. the t.racks DSP 306

    the t.racks DSP 306

    In stock
    €318
    £280.33
  7. Elysia xfilter

    Elysia xfilter

    In stock
    €1,155
    £1,018.16
  8. the t.racks DSP 206

    the t.racks DSP 206

    In stock
    €288
    £253.88
  9. HoTone Xtomp

    HoTone Xtomp

    In stock
    €199
    £175.42
  10. Drawmer 1974

    Drawmer 1974

    In stock
    €966
    £851.56
  11. Waves Abbey Road Studio 3 + Nx Track

    Waves Abbey Road Studio 3 + Nx Track

    In stock
    €135
    £119.01
  12. tc electronic TC1210-DT

    tc elec­tronic TC1210-DT

    In stock
    €145
    £127.82
  13. Artec SE-EQ8 Graphic EQ

    Artec SE-EQ8 Graphic EQ

    In stock
    €34
    £29.97
  14. tc electronic DVR250-DT

    tc elec­tronic DVR250-DT

    In stock
    €209
    £184.24
  15. tc electronic TC2290-DT

    tc elec­tronic TC2290-DT

    In stock
    €209
    £184.24