2. Principles of operation

If we were to transmit a natural, untreated signal with its full dynamic range, we would often have a problem: Even in nature, sound events can cover a dynamic range of more than 100 dB; think of the difference in volume between the rustling of leaves and loud thunder during a strong storm, for example.

In radio broadcasting, these kinds of dynamics cannot be transmitted; here, the usable dynamic range lies between 40 and 50 dB. To satisfactorily transmit the wide dynamic range of a symphonic orchestra, for example, the signal must be compressed. This is achieved with broadcast compressors.
In order to achieve a satisfactory sound on many different playback systems, a compromise must be found between the dynamic range of the recording and the technical capabilities at the playback end. If you have access to a good level meter (such as the ones on a mixing console), you can see for yourself how heavily some music is compressed. Listen to a recent rock or pop album and watch the meter: does it move much? Probably not. Whether that is a good thing is subject to much debate among audio engineers, but in reality the dynamic range of most current rock and pop music is reduced to a mere 3-6 dB.

How is this achieved? The compressor makes it possible! But how? The following chart shows how compression works, physically speaking:

Kompressor Kennlinie
Compression graph

At a compression ratio of 1:1, nothing happens. At higher ratios (2:1, 4:1, 6:1, or 8:1), the output signal is progressively „squeezed“ in relation to the input, resulting in a reduced dynamic range.

The second important parameter of a compressor is its threshold. It describes the level above which the compression sets in. For example, if the threshold is set to -10 dB, then the compressor will only process those portions of the signal that are louder than -10 dB.

Your Contacts

Best rated products

  1. DBX 286 S

    DBX 286 S

    In stock
    €135
    £119.46
  2. FMR Audio RNC 1773

    FMR Audio RNC 1773

    In stock
    €211
    £186.72
  3. DBX 166 XS

    DBX 166 XS

    In stock
    €144
    £127.43
  4. TC-Helicon VoiceTone T1

    TC-Hel­icon VoiceTone T1

    In stock
    €85
    £75.22
  5. Samson S-Com 4

    Samson S-Com 4

    In stock
    €121
    £107.07
  6. FMR Audio RNLA 7239

    FMR Audio RNLA 7239

    In stock
    €249
    £220.34
  7. DBX 266 XS

    DBX 266 XS

    In stock
    €117
    £103.53
  8. DBX 160A

    DBX 160A

    In stock
    €489
    £432.72
  9. Klark Teknik 76-KT

    Klark Teknik 76-KT

    In stock
    €199
    £176.10
  10. ART Pro VLA II

    ART Pro VLA II

    In stock
    €406
    £359.27
  11. Waves Gold

    Waves Gold

    Download license
    €295
    £261.05
  12. Warm Audio WA76

    Warm Audio WA76

    In stock
    €555
    £491.12
  13. Softube Console 1 Mk 2

    Softube Con­sole 1 Mk 2

    In stock
    €389
    £344.23
  14. Klark Teknik KT-2A

    Klark Teknik KT-2A

    In stock
    €319
    £282.29
  15. ART Tube MP/C

    ART Tube MP/​C

    In stock
    €129
    £114.15

Top Brands

  • Chandler Limited
  • Tube-Tech
  • Rupert Neve Designs
  • Tegeler Audio Manufaktur
  • Empirical Labs
  • Eventide
  • the box pro
  • IK Multimedia
  • Drawmer
  • IGS Audio
  • Positive Grid
  • PAS

Most popular products

  1. Klark Teknik 76-KT

    Klark Teknik 76-KT

    In stock
    €199
    £176.10
  2. DBX 286 S

    DBX 286 S

    In stock
    €135
    £119.46
  3. Klark Teknik KT-2A

    Klark Teknik KT-2A

    In stock
    €319
    £282.29
  4. DBX 166 XS

    DBX 166 XS

    In stock
    €144
    £127.43
  5. Softube Console 1 Mk 2

    Softube Con­sole 1 Mk 2

    In stock
    €389
    £344.23
  6. Drawmer SP2120

    Drawmer SP2120

    In stock
    €515
    £455.73
  7. the t.racks DSP 306

    the t.racks DSP 306

    In stock
    €318
    £281.40
  8. Tascam TA-1VP

    Tascam TA-1VP

    In stock
    €339
    £299.98
  9. Waves Abbey Road Studio 3 + Nx Track

    Waves Abbey Road Studio 3 + Nx Track

    In stock
    €135
    £119.46
  10. the t.racks DSP 206

    the t.racks DSP 206

    In stock
    €288
    £254.85
  11. tc electronic TC1210-DT

    tc elec­tronic TC1210-DT

    In stock
    €145
    £128.31
  12. tc electronic DVR250-DT

    tc elec­tronic DVR250-DT

    In stock
    €209
    £184.95
  13. Warm Audio WA-2A

    Warm Audio WA-2A

    In stock
    €888
    £785.80
  14. tc electronic TC2290-DT

    tc elec­tronic TC2290-DT

    In stock
    €209
    £184.95
  15. UnderToneAudio UnFairchild 670M II

    Under­Ton­eAudio UnFairchild 670M II

    In stock
    €9,990
    £8,840.21