When we speak of audio signals, we usually don't refer to the actual acoustic waves propagating through the air. Instead, we often think of audio as a voltage - with a one volt peak value as the ‘0dBu’ reference, clipping the average analogue ‘line’ signal circuit around +24dBu - measured in volts close to the commonly used balanced power supply of 15v. And when we discuss digital audio, we think of a digital code representing a voltage - with 0dBfs ‘full scale’ representing the maximum peak level.read more
Skype, Facetime, YouTube… I’m not going to talk about them, though they use networks to carry audio. I’m talking about audio networks for professional audio - you know, CobraNet, EtherSound, Dante, Ravenna, AVB and so on. I can think of at least ten different types of professional audio network that I have used during the last decade. All of them claim to carry uncompressed digital audio around a studio/concert hall/festival site/other entertainment venue. They all have slightly different features and advantages. But which one has the best sound?read more
This week an odd topic: analogue synthesis. In the 1970s and early 80s, Yamaha was a leading manufacturer of analogue synthesisers. Where the MiniMoog is the archetype of the monophonic (one voice) keyboard synthesiser, the Yamaha CS80 is the undisputed ‘mother of polysynths’, regarded as the most impressive achievement in audio engineering in the seventies.read more
It was a big debate in the previous decennium: using external word clocks to influence a digital audio system’s time accuracy. With the introduction of the ‘Precision Time Protocol’ in gigabit networks, the discussion slowly died out and the choice of system clock to influence audio quality has basically disappeared. Many networked I/O racks don’t even have a word clock BNC connector anymore. What happened ?read more
Audio networking - everyone’s doing it now, aren’t they? The entry cost is now under €50 for some audio networking software and a network switch. But how often do we consider the risks and requirements before jumping in?read more
The invention of the vacuum tube more than 100 years ago made many things possible –radios, televisions, even computers. And, of course, audio power amplifiers to drive the speakers in them… and also professional audio systems. Since then, after the transistor started to replace the vacuum tube in the 1970s, power amplifiers have grown from a few watts for driving small speakers up to several kilowatts driving high-powered line arrays.
Since the 1970s, the market for sound reinforcement systems has matured, offering thousands of different loudspeaker cabinets and separately-sold power amplifiers to match any application. But this has introduced a challenge: what power amplifier to select for what speaker?
A lot can happen in ten years. If you had been experimenting with the application of network technology in live audio systems back in 2007, you would have been a true pioneer - marketing people would call you an ‘early adopter’. Starting with 100Mb Ethernet technology protocols Cobranet and Ethersound, later introducing proprietary protocols Optocore and Rocknet, the live audio world quickly learned to make use of the exciting possibilities and functionality of network technology. Ten years later, the market adopted gigabit Ethernet networks as a standard - nowadays there’s hardly a professional audio mixer, stage rack or DSP processor that doesn't have an RJ45 connector to exchange audio with the world. Sound engineers learned to use network cables, program switches and design ad-hoc network structures to make their lives easier. This micro-tutorial presents the five most important topics in discussing audio networks.read more
Today's professional audio market uses chips made by a handful of digital signal processing (DSP) manufacturers. The most-used chips are made, in alphabetical order, by Analog Devices, Intel, Motorola, Texas Instruments and Yamaha. Over the past three decades, DSP chips have developed from low capacity chips to the advanced 32-bit and higher bitrate systems used in today's processors and mixers, with manufacturers constantly improving performance. This performance is generally indicated by three properties: DSP power, Audio quality and Sound quality.read more