Tag Archives: Audio Engineering

Asheville, Walnut Cove, Biltmore Forrest and Western North Carolina’s Audio and Home Theater specialists present Cane Creek AV and Paul McGowan – PS Audio, Intl.

Devils and details

Part of the challenge in audio engineering is to know when to use certain processes or devices and when to use others. For example, a tube in the input stage works well, but not so much in the output. Or, a capacitor used as a DC blocker might sound better than the complexity of a servo, or, vice versa.

Analog integrated circuits, like op amps, can typically be bettered by their discrete counterparts in some cases, but not all. For example, if component matching is a critical aspect to your design then there’s likely no better process than integrating everything on a single piece of silicone. Each component tracks the temperature variations of the other for near-perfect matching.

Yet, in the same way separates can outperform integrated amplifiers, there are disadvantages to IC solutions too. The limitations of single silicone, including low power requirements and a lack of isolation between components, can hinder performance levels in highly resolving systems like the kind you and I might want at home.

It’s always a good idea to keep sweeping proclamations of better and worse at a minimum.

Like just about everything else in life, it’s the details that flush out the devil.

Clever Engineering

A few posts ago we covered the topic of dynamics in loudspeakers and how a small pair of speakers really isn’t capable of moving large volumes of air. Unfortunate but true for those of us that enjoy listening to realistic sound pressure levels of orchestral music.

I have experienced “the real deal” with large loudspeakers like the Infinity IRS and the Genesis I’s among other large systems, but never with smaller ones. Is it possible? Obviously most of us (including me) neither have the space nor the funds to own a massive loudspeaker system. The answer is yes if we apply a little bit of clever engineering.

I may have written about this before but years ago I figured out a way to trick the ear into believing the soundfield dynamics were linear and uncompressed in a small speaker system. It’s been my experience that we perceive these compressed dynamics as a limitation of soundstage width with volume. This means that as an orchestra gets louder – really loud – the apparent width of the soundstage should increase beyond the size of the room – and dramatically so. Unless you have a large loudspeaker that simply dominates the room you won’t get this impression when the orchestra plays loudly. That is unless you apply my trick.

What I did was simple. I took another pair of loudspeakers, a small bookshelf pair, and placed each one next to the outer sides of of the primary speakers – 90 degrees from the front baffle of the primaries so they pointed to the outside side walls of the listening room. I then connected the new speakers to a power amp whose input had a threshold gate on it and set the threshold so that the speakers started working only when the music was medium loud.

What happened was fairly amazing to any listener. As the music became loud the soundstage width increased exactly as it would have in real life or with a huge loudspeaker pair. It did this because the new speakers added the missing volume levels – but the energy was directed specifically at the sidewalls of the room – not the listener. Some clever speaker manufacturer could easily add side mounted drivers into their designs and make a passive threshold gate using opto couplers so the primary amp could handle everything should anyone want to.

So you see that by using a bit of clever engineering one can overcome the hurdles we encounter if the desire is there.

Paul McGowan – PS Audio Intl.