8. Introduction to Acoustics

The bad news is that every room is different. The good news is that a basic introduction to the principles of acoustics should help you to solve most problems.

Sound waves prefer to travel in circles, like waves from a stone dropped into a pool. For PA purposes, this pattern is difficult to work with, so PA speaker cabinets are engineered to direct sound in more manageable ways. Essentially, they project out into the auditorium before the sound begins to disperse into its natural pattern.

It’s worth trying to determine how your speakers radiate their sound, so you can place them to maximum advantage. And be careful how you place them in relation to each other - the sound from one speaker can cancel out the sound from another.

The one factor over which you have very little control is the room itself. Glass, concrete and tiles are the enemy of good sound, because they reflect sound waves all over place. Short of carrying your own supply of very thick foam rubber to fix to the walls, there's not much you can do, though you should try to place the speakers to keep the damage to a minimum.

A ‘sound check’ is essential, but take nothing for granted - a lot changes once people come in. The audience does at least help to reduce the reflected sound, but it’s vital for everyone on stage, and the sound engineer, to take note of the way the sound has changed and adjust their settings accordingly – it’s normal to experience a substantial loss of high frequencies and reverb.

Your biggest challenge will come when playing in the open air. Sound waves lose their energy rapidly, so you will need a much more powerful system to cover a relatively small space.

Delay line

In larger rooms, a delay line may be required. This is a system that delivers the sound to the back of the hall. However, for listeners sitting mid-way between the front and the back, or at the sides, there is a risk that the two speaker sets will conflict, creating a noticeable echo. In a delay line, a time delay is built into the signal path, equivalent to the distance from the front speakers, to ensure that the sound is delivered consistently to all areas.

Line array

A typical line array

Larger venues need larger sound-reinforcement systems, with more square inches of cone to push the air. The trouble is, the more speakers you have, the greater the risk that some of their frequencies will cancel each other out, and you will actually end up with a worse sound than from a single speaker. ‘Line arrays’ are designed to combat this problem, and have become the standard for larger arenas and outdoor events. They are built using speaker modules with clearly defined beam angles - that is, the breadth of coverage of the air pushed out. By aligning these modules carefully with each other, you can actually build a single, cylinder-like column of sound in which all frequencies are transmitted without conflicting with each other. You can also distribute a full sound to a large and scattered audience of the kind you get at festivals. Unless you are a professional sound engineer, however, you are unlikely to have to concern yourself with the complexities of line arrays. By the time you're playing venues where they matter, you can leave it to the roadies to sort things out!

O seu contacto

Os melhores produtos relacionados

  1. the box PA 252/E800 Set
    BUNDLE

    the box PA 252/​E800 Set

    Em stock
    € 585
  2. Behringer EPS500MP3

    Beh­ringer EPS500MP3

    Em stock
    € 329
  3. the box TA Power Bundle
    BUNDLE

    the box TA Power Bundle

    Em stock
    € 1.499
  4. the box TA Set Basis Bundle
    BUNDLE

    the box TA Set Basis Bundle

    Em stock
    € 1.199
  5. the box PA110 A Bundle
    BUNDLE

    the box PA110 A Bundle

    Em stock
    € 362
  6. the box PA302 A Bundle
    BUNDLE

    the box PA302 A Bundle

    Em stock
    € 519
  7. the t.amp PA 4080 Package Stand Set
    BUNDLE

    the t.amp PA 4080 Pac­kage Stand Set

    Em stock
    € 225
  8. the t.amp PA 4080 Package

    the t.amp PA 4080 Pac­kage

    Em stock
    € 189
  9. dB Technologies ES602

    dB Tech­no­lo­gies ES602

    Em stock
    € 333
  10. Bose L1 Compact

    Bose L1 Com­pact

    Em stock
    € 829
    € 1.099
  11. LD Systems Maui 11 Mix

    LD Sys­tems Maui 11 Mix

    Em stock
    € 475
    € 699

Marcas populares

  • JBL
  • Yamaha
  • Solton
  • RCF
  • Alto
  • Superlux
  • ANT
  • EV
  • Seeburg
  • KS audio
  • Fun Generation
  • the t.amp

Os produtos mais populares

  1. Bose S1 Pro System

    Bose S1 Pro System

    Em stock
    € 555
  2. LD Systems Maui 28 G2

    LD Sys­tems Maui 28 G2

    Em stock
    € 919
    € 1.189
  3. dB Technologies ES602

    dB Tech­no­lo­gies ES602

    Em stock
    € 333
  4. Bose L1 Compact

    Bose L1 Com­pact

    Em stock
    € 829
    € 1.099
  5. JBL JRX 212

    JBL JRX 212

    Em stock
    € 179
    € 329
  6. Alto TX 210

    Alto TX 210

    Em stock
    € 133
    € 179,99
  7. the box pro DSP 112

    the box pro DSP 112

    Em stock
    € 229
  8. EV ELX 112P

    EV ELX 112P

    Em stock
    € 489
    € 702,81
  9. EV ZLX 12P

    EV ZLX 12P

    Em stock
    € 359
    € 484,33
  10. HK Audio Premium PR:O 18 Sub A

    HK Audio Pre­mium PR:O 18 Sub A

    Em stock
    € 645
    € 799
  11. EV ELX 112

    EV ELX 112

    Em stock
    € 259
    € 350,81
  12. Fun Generation PL 115 A

    Fun Gene­ra­tion PL 115 A

    Em stock
    € 149
  13. Fun Generation PL 112 A

    Fun Gene­ra­tion PL 112 A

    Em stock
    € 129
  14. the box CL 118 Sub MK II

    the box CL 118 Sub MK II

    Em stock
    € 555
  15. RCF ART 312 A MK IV

    RCF ART 312 A MK IV

    Em stock
    € 349
    € 449