• Interview with Pat Quilter (QSC)

    Interview with Pat Quilter, (the "Q" in QSC).

    In 1968, steeped in the anti-corporate ethos of the '60s and '70s, QSC founders Pat Quilter and Barry Andrews accidentally bumped into each other and started QSC Audio. From its humble beginnings crafting handmade guitar amps from a one-room shop in Orange County, California (USA), short on experience but rich in dreams, drive, and a desire to do things differently and avoid getting "a real job", the company has became one of the most respected in the industry.

    Pat concentrated on designing and building the amplifiers, Barry took charge of sales and marketing, and Barry's brother John, who had recently obtained his business degree from USC, was brought in to handle the finances. In the early 70's they concentrated on the power amplifier business and at the turn of the century they added loudspeaker systems to their product range.

    We thank Mr. Quilter for kindly accepting to be interviewed by Doctor ProAudio. Questions combine forum users' suggestions as well as editorial ones.


    ¤ [Doctor ProAudio] - Let’s start from the beginning. How and when did you become interested in sound?
    ¤ [Pat Quilter] - My parents enjoyed records as I grew up and I liked to hum along. I also spent many hours in front of early TV watching old cartoons, with their happy 1920's music tracks. This led to an interest in collecting old records in college, when they were still cheap. I also acquired a wind-up Victrola and later an old radio, and began to learn audio electronics by hooking an electric pickup to it and trying to improve response.

    ¤ [DoPA] - Do you have formal electronics training?
    ¤ [PQ] - Everything I needed to know to get started, I learned in my high school physics class. As I got more interested, I began to read hobby electronics magazines. Although I began to re-orient my college studies towards electronics, I was unable to find much on circuit design. I actually took some pride in re-tracing the steps of the electronics pioneers of the 1920's.

    ¤ [DoPA] - What does music mean for you?
    ¤ [PQ] - Music is a universal language that really seems to tap into deep emotional responses across many cultures. I am fascinated by the history and development of music, especially popular music of the 20th century.

    ¤ [DoPA] - What made you decide to pursue a career in audio?
    ¤ [PQ] - In 1967, my younger brother (who became the professional musician in the family) had a friend who needed a bass amplifier. He couldn't afford a name-brand product, but using the time honored question "how much have you got?" I determined that I could meet his needs and make a little money. I ended up having to do everything over twice, but it worked in the end, and I still made about three cents an hour on the project.

    ¤ [DoPA] - Once you decided to concentrate on power amps, how hard was it to get the market share and reputation that you have today?
    ¤ [PQ] - It was mostly a long slow process of development - constantly improving, struggling to build our company and our product portfolio on a shoestring budget. "Success" took about 20 years to arrive.

    ¤ [DoPA] - What is you approach to designing a power amplifier?
    ¤ [PQ] - I start with the basic needs - what is the power target, how does this translate into component voltage and current ratings, and what general architecture will we use? Then the rest of the power ratings and component sizes can be determined. Although I have developed a few unique approaches in an effort to keep the circuitry simple, once you have set up your power architecture, it's a matter of craftsmanship and refinement to get the overall audio performance up to top-notch standards. Of course there are many problems beyond clean audio performance, such as overload behavior, protection, power supply dynamics, hum and emissions, cooling, and overall reliablity that must also be solved for best overall results.

    ¤ [DoPA] - What are your thoughts on Class-D amplification?
    ¤ [PQ] - Some years ago we released an early speaker series with an 800W plus 200W Class D bi-amp. The speaker series did not sell well for other reasons, but the amplifier worked great. The PL-380 is our current Class-D flagship amplifier topping the PowerLight 3 Series, with 8000 watts of total power. The K-Series speaker line uses a highly refined 1000-watt 2 channel Class-D amp with world-wide AC power capability and internal DSP processing for "Intrinsic Correction", QSC's trademark for processing that brings the best possible results out of each individual speaker. Perhaps we haven't made a sufficiently large market splash about our technology, but we view Class-D as the latest tool for improving the efficiency of amplifiers and allowing more performance in smaller units.

    ¤ [DoPA] - Crest factors for current pop and rock recordings can get as low as 6 dB. How does that affect product design?
    ¤ [PQ] - We have to take this average duty cycle into account. Coming from our original guitar-amp background, we are used to the idea that amps can be pushed hard, and should still sound musical. We typically design for higher-than-average duty cycles, and have long focused on efficiency improvements as a means to handle higher average powers with lower thermal losses.

    ¤ ¤ [DoPA] - It seems that power amps with integrated DSP have become popular. Does QSC have plans for one?
    ¤ [PQ] - So far, we have handled DSP processing as an "outboard" function, connecting to the Dataport that we have provided for many years as an intimate connection to the important signals inside an amplifier. This way, only the customers interested in DSP capability need to bear the cost. However, DSP is becoming less expensive and more common, so we will be moving in the direction of built-in DSP. Our successful K-Series powered loudspeakers use an internal DSP chip to enhance audio performance and protection.

    ¤ [DoPA] - So far most of your loudspeaker products have been non-powered. What’s the reason for that? Will that change in the future?
    ¤ [PQ] - We felt it was necessary to understand the loudspeaker business from the ground up before we could do a truly successful marriage of power amps and transducers. We did introduce a 3000 watt self-powered touring-grade speaker system early on, but the combination did not truly add value for our customers. However, the self-powered HPR and the new K-Series are already dominating our speaker sales revenue. By using the latest Class-D and DSP technology, we feel that we have provided a new standard for powered speakers, with many more models to come. In other cases, it is still more economical to drive many small distributed speakers with single large amplifiers, although this may change in time as well.

    ¤ [DoPA] - How much of your turnover do speaker products represent? Do you see that growing in the future?
    ¤ [PQ] - Speaker sales have become about half our revenue, and are still growing rapidly. Much of this growth is in powered speakers, which of course represents overall growth of our amp business as well.

    ¤ [DoPA] - The market is crowded with Asian-made imitations of western power amps, including QSC’s. Lately, however, a reference US-based competitor or yours has been using an OEM amp that was largely inspired on one of your RMX amplifiers. Any comments on that and the whole issue of copying?
    ¤ [PQ] - Well, I started out over 40 years ago copying certain parts of designs that looked promising, but I went on to improve and refine them. Everyone needs to start somewhere. The basic QSC designs that seem to be popular targets for copying are now 15 to 25 years old, so I guess you could say that recognition of their value took a while. We expect to be pioneering new and better designs, especially in the emerging field of Class D power.

    ¤ [DoPA] - There seem to be a lot of people that miss the sound of MX and EX amps. Why do you think that is? The softer power supply, maybe?
    ¤ [PQ] - The whole question of "sonic signatures" in linear power amps remains a mystery to me, as the measurable differences in their linear range are very slight, but the dynamic response of the power supply does have an effect during low frequency clipping. Some prefer the mellowing effect of a softer supply, others prefer the stiffer sound of a well-regulated supply. We have leaned towards greater regulation as we developed switchmode supplies.


    ¤ [DoPA] - Which side of the Atlantic would you say the best competitor products come from?
    ¤ [PQ] - Well of course I would like to say from Costa Mesa in Southern California! But realistically, there are several leading companies in the USA and Europe that make very good products with excellent performance. The choice gets down to size, weight, rack spaces, auxiliary features such as processing, and of course price. Many users have opinions as to which ones sound better, but these opinions tend to vanish in blind ABX testing, so I suspect they have their favorite amps for other tangible reasons.

    ¤ [DoPA] - What’s your take on AVB?

    ¤ [PQ] - Since people have been watching TV with sound for 50-plus years, it does seem natural that audio and video should be integrated on a network. QSC was an early supporter of Cobranet, an open standard for audio networking, but as certain improvements were made to solve various problems, compatibility became a problem which undermines the whole concept of a "standard". As a result, QSC made a strategic decision to develop our proprietary "Q-Lan" in order to provide the best reliability and performance for Q-Sys customers. I understand that Q-Lan has some technical advantages over AVB, and we are looking into the question of video transport as a future upgrade.

    ¤ [DoPA] - If you could not be in involved in audio, what we would you like to do?
    ¤ [PQ] - I've always been fascinated by electric cars. I think the personal vehicle is one of the greatest empowering invention of the 20th century, but we need to make cars cleaner and more efficient. As an electronic engineer, I just had to lease an EV1 for the experience, and despite some problems, it was truly a glimpse into the future.

    ¤ [DoPA] - Which way do you see the industry going in the future?
    ¤ [PQ] - More use of networking and digital processing, to enable more creative applications for amps and speakers.

    ¤ [DoPA] - Which way will QSC be going on in the future?
    ¤ [PQ] - Given the increased need for software and systems integration, and the extreme complexity of digital technology, we believe QSC must provide complete system solutions so we can ensure complete customer satisfaction. Debugging a system from multiple suppliers is not really manageable. There will always be specialty products from focused competitors that offer more of some particular attribute, but getting the best overall results depends on the integrity of the system, so at least the core components need to come from a single source.

    ¤ [DoPA] - Any other thoughts you would like to share with our readership?
    ¤ [PQ] - Although I have had a long career as an analog power designer, and I personally value simplicity and directness in my gear, the incredible and unrelenting improvements in digital technology tell me that "we ain't seen nothing yet".

    [Note: https://www.qsc.com/resources/video-library/ has a selection of videos that underline how serious QSC is about product development and production]