Audio Effects – Compression & Ring Modulation

October 5, 2006

Moving on down the line, today we continue our series on audio effects and editing tools. In the past few articles we’ve such effects as reverb, flange, delay, and noise gate. If you enjoy dabbling in audio production, you’re going to enjoy today’s article. We’ll be discussing compression, which is instrumental in the audio production arena. And also we will also be discussing ring modulation, which is a bit more fun and flexible audio effect. So, in today’s article get ready to learn about both, compression, and ring modulation. Let’s discuss how these effects work and why they work the way they do.  

CompressionCompressors reduce the dynamic range of an audio signal, if its amplitude exceeds a set threshold. The amount of range reduction is determined by a set ratio. If the ratio was set to 6:1, the dB would need to be increased by 6 to increase the output signal by 1 dB over the threshold. The way that a compressor reduces dynamic range is by using a variable-gain amplifier, which reduces the gain of an audio signal. Analog compressors typically carry this out by using a voltage controlled amplifier, which reduces the gain as the input signal’s power increases. Digitally, compression is carried out via DSP (digital signal processing), and this is the most modern version of the effect. The main use of compression is to make music sound louder without increasing its peak amplitude. Compressing the peak, (loudest signal), allows you to increase the overall gain without exceeding the dynamic limits of your reproduction device. Compression is widely used in TV and radio, allowing maximum perceived volume, without going over the strict limits imposed by most broadcasting companies. 

Ring ModulationRing modulation is achieved by multiplying two audio signals, with one signal being a simple waveform such as a sine wave. They combine the two signals, outputting the sum and difference of said signals. Ring modulation is related to amplitude modulation and frequency mixing, and it produces a signal rich in overtones. It is well suited to produce metallic and bell-type sounds. Modern ring modulators, like modern compressors, use digital signal processing to produce the effect. Using DSP to do this produces a mathematically perfect signal output, which some musicians do not like. You can come up with some interesting harmonics using a ring modulator by changing the frequency of the two input waveforms.  

This is the third installment in my continuing series on audio effects and engineering tools. We discussed compressors and ring modulators today, a couple of very interesting and deep effects. I learned a lot myself, so I hope that you did as well. We will be continuing this series indefinitely, until we run out of effects! I hope that this has shed a little light on these two amazing pieces of equipment, ultimately making your next music project a bit more interesting and productive.  

Jason Cole and DiskFaktory Mastering offer great professional mastering services and information regarding audio engineering and CD mastering in California. Get the professional mastering information you are seeking now by visiting


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