Does my sound system need DSP? What is it?
Good sound quality very rarely just happens ‘out-of-the-box’, but takes a number of different components to achieve. Part of this is the quality of the equipment used, but another large element is the ability to tune or equalise (EQ) the sound system to make it sound as good as possible. This is where DSP comes in.
But what is DSP and why does my church sound system need it?
Traditionally, lower-cost church sound systems only have very basic bass and treble controls for the main output, with no ability to adjust this individually for each input channel. This can lead to very poor performance as there are no means to compensate for the particular frequency characteristics of budget loudspeakers. Typically cheaper loudspeakers will reproduce some frequencies far more or far less than others, due to their cheaper materials and lower design values.
As a result, two things will happen when you turn the volume of the system up. Firstly, the tone of the sound will change, with music and speech sounding thin and nasal. Secondly, when using microphones to capture speech, the microphone may start to pick up reflected or direct sound from the loudspeaker and re-amplify the loudest frequencies which will lead to nasty acoustic feedback (that piercing ringing sound we have all heard come from loudspeakers at one point). The acoustic response of the room can further compound this issue of feedback and poor audio quality.
Happily, there is an effective way to reduce these undesired effects and make the most of even fairly budget loudspeakers. The answer: Digital Signal Processing, or DSP for short. In a very basic sense, this is a small box which will sit between the output of the mixer and the input of the amplifier powering the loudspeakers. It contains audio processing that allows for very accurate mitigation of the frequencies causing the problems of feedback and gives an opportunity to compensate for the frequency response of the loudspeakers.
During the installation phase APi uses test equipment and importantly our experience of working in lively church acoustics to make the system sound the best it can, meaning that even our lowest-cost systems perform well.
So if I can make even a budget church system sound good, then why should I pay more?
DSP is a valuable tool and does allow for an increase in quality when using budget equipment, but it does not make a system which will compare to one where more capable loudspeakers have been chosen. DSP will be used even with higher-end systems, but for fine-tuning rather than fixing difficulties with limited speaker performance.
At some point applying a lot of DSP will have an effect on the overall quality of reproduction you may fix one issue and create another. For example, boosting the bass output will make a speaker sound better at low volume, but turning it up with this added bass could end up exceeding the limits of the speaker driver and causing damage.
Ultimately, adding DSP to any system will improve the achievable volume before the onset of feedback and smooth out the frequency response, making the system sound more natural and making the operation of the system far easier on a week-to-week basis.
Digital signal processing also gives possibilities to add delay to loudspeakers and other advanced features which allow even further fine-tuning of a sound system for maximum performance.