Tech Feature

Audio Networks and Switching Your Way to PTPv2 Support

Audio networks are hardly new, with a huge increase in the number of projects using audio networks over the past few years. Besides the various solutions (like Dante, RAVENNA, etc.), which have made this possible, there are a number of protocols working under the surface too. One of these is IEEE 1588 (otherwise known as PTP or Precision Time Protocol), one of the protocols that underpins many of the various audio (and video) networking standards.

A hallmark of many people that I have met in the world of professional audio is the ability to get the show working quickly. Behind the scenes of most live audio and installation deployments are a set of compromises, sometimes small and sometimes not so small. This month’s article is a tale of such compromises.

Managing low frequencies is one of live audio’s constant challenges. We deal with room nodes, architectural resonances, uneven coverage and unwanted spill. The last two decades have brought about the ready availability of digital signal processing (DSP) and digital consoles. DSP is now in almost everyone’s arsenal, allowing the easy creation of cardioid arrays with everyday tools.

Since the beginnings of professional audio, we have needed more output, coverage, and frequency response than a single loudspeaker transducer could provide. Due to the limitations of loudspeaker drivers, much of the effort in professional loudspeaker design has been expended in combining multiple drivers in a single loudspeaker box, and then combining multiple boxes together into arrays. Even with dramatic increases in modern transducer performance, it would seem that combining multiple loudspeakers together — whether for response, coverage or output — will continue to be a perpetual fixture of the industry.

With the imminent arrival of InfoComm 2016, the professional audio industry is rolling out the booths, demo rooms and display trucks to show off what’s new in professional audio technology. Among the myriad sights and sound, many manufacturers will be displaying their latest and greatest loudspeakers.

Generators and portable power distribution are central to professional audio. Electricity is the preferred means of transferring energy. It is the lifeblood of all pro audio gear. The specific details of portable power distribution for pro audio are often outside the daily interactions of the local electrician. In these circumstances, it can fall to the audio practitioner to clarify the relevant codes and procedures to the electrical professionals in the name of event safety. A solid conceptual understanding of portable electrical power distribution should be a goal for all pro audio professionals.

I discovered ribbon mics late in my career, after I’d been engineering for 20 years. I only knew the classics before that, such as the RCA 44 and 77-DX, which looked great in glass cases or featured in photos of music stars of previous generations. About 2001 I started using some of the newer generation of ribbon mics and I fell in love with them: the Royer R-121 and R-122, the AEA R84 and R88, along with standards such as the Coles 4038 and Beyerdynamic M160 and M500. I was hooked, with my ribbon mic collection eventually topping out over a dozen mics, ranging in date of origin from 1932 all the way to the present. But I used them primarily in the studio and became very familiar with their strengths. I learned to love the figure-8 pattern and recognize where it truly excelled.

This month, we are going to talk about plywood. Plywood is everywhere in professional audio. It is used in trailers and ramps, speaker boxes and cases, stands and stages. Even though plywood is ubiquitous, we rarely pay it much mind. At least if you ignore the constant complaints about how heavy it is. Plywood is a versatile material, and an excellent introduction to a class of substances known as composites. The behavior of plywood is a good example to delve into in terms of thinking about some of the properties of materials in general. This month, our aim is to uncover some of that in a way that shows why plywood is preferred to solid wood for many structural applications.

Other than dead silence, feedback must be the most hated thing in professional audio. Feedback has been with us since the first microphone was placed in front of a speaker and is something every audio technician learns to manage. As long as loudspeakers are returning sound information back to presenters and performers the potential for feedback will remain. This month, we’ll define the cause of feedback, and then see how some aspects of monitor speaker design can contribute to causing feedback.