Q&A: Ken Heng Gin Loo – DIY Audio Appeals to Applications Engineer

Ken Heng Gin Loo

Ken created the diy-audio-guide.com website because of his interest in DIY audio, in particular tube amplifiers, Class-T amplifiers, NOS DAC, high-efficiency loudspeakers, and high-quality audio reproduction.

SHANNON BECKER: Tell us about your background and where you live.

KEN HENG GIN LOO: I’m a Malaysian Chinese. I spent a wonderful childhood in a small and peaceful town called Taiping, Perak, up North in Peninsular Malaysia.
I’m fortunate that my father could afford to send me overseas to the United Kingdom to pursue a bachelor’s degree after locally earning my diploma in Electrical and Electronics. Now, I’m a graduate in Electrical and Electronics Engineering (Honors) from the University of Manchester, UK.

I currently live on a beautiful tropical island named Pulau Pinang (aka Penang) in Malaysia. It is an urbanized and industrialized state that houses several the multinational corporations (e.g., Intel, Agilent, Motorola, Altera, National Instruments, etc.). Yet, it retains its historical heritage and it is one of the UNESCO World Heritage sites. Downtown is filled with historical sites, excellent local delicacies and seafood, and many beachside resorts.

I live in a terrace house with my lovely wife Brenda and 3-month-old baby girl Ember. In the past, I worked as an engineer for several multinational corporations. Now I work at Intel (for more than eight years) as an applications engineer. I focus on customer-enabling team program management, working with high-speed electronics applied in tablets, notebooks, and PCs.

SHANNON: How did you become interested in audio electronics?

KEN: I was “trained” in hi-fi very early, way back in my primary school years. I’m fortunate to have a hi-fi enthusiast as a father. He plays vinyl, and previously used cassettes before moving to CDs in the 1990s. I was brought up (or spoiled?) with high-quality stereos since I was a youngster.

I started to like tube equipment when I heard the combination of a Unison Research Simply 2 and a B&W 601S2 speaker in a shop in Hsinchu, Taiwan. I seriously started to create DIY audio projects when
I was working in Taiwan in early 2000. A friend, who was also a tube dealer, introduced me to his DIY 300B tube amplifier that was driving a pair of vintage Tannoy 15” dual-concentric speakers. It was the Tannoy GFR, if memory serves me right. The sound they produced was made in heaven and no setup that I’d encountered at that time was close to producing what I heard that day.

I was hooked on the glowing tubes. I started reading about vacuum tubes online, in books, and in magazines (e.g., Sound Practices, Audio Amateur, audioXpress, etc.). I wanted to learn more about vacuum tubes so that I could build a sound system of my own. I also started “wasting” money collecting NOS tubes for my future projects. Now, I have more tubes than I will ever need in my entire lifetime. Maybe if my daughter inherits my interest in audio technology, she will find a use for them. Who knows?

Among his many projects, Ken built a 2A3 amplifier. However, instead of a 2A3 tube, he used the double plate NOS 6B4G because it has the same electrical characteristics as a 2A3 tube. The main difference is that the filament uses 6.3 instead of 2.5 V.

Among his many projects, Ken built a 2A3 amplifier. However, instead of a 2A3 tube, he used the double plate NOS 6B4G because it has the same electrical characteristics as a 2A3 tube. The main difference is that the filament uses 6.3 instead of 2.5 V.

SHANNON: Describe your first personal project. Why did you build it? Is it still in use?

KEN: Tube amplifiers were still uncommon in those days and purchasing one was costly. It was definitely out of my budget when I was a young engineer. Back then, an ordinary tube amplifier alone was two or three times my monthly pay. Since I have knowledge in electrical engineering and electronics (well, sort of, since I studied all solid-state electronics), I thought I would attempt to build a tube amplifier. I thought making a tube amplifier from scratch certainly would not be difficult for me. So, I started building tube amplifiers because the DIY methods made them accessible to me.

A Taiwanese friend assisted me with my first build. He did most of the design work and I did all the soldering since I was still very new to DIY tube amplifier construction. It was a two-stage all triode amplifier with a 300-B direct heat triode driven by a 5842 miniature triode. The sound was sweet and warm even though it was (un?)matched with a small B&W 601S2 bookshelf speaker. (I still have this pair of speakers today!) They are definitely 10 times (exaggerated!) better than all the entry solid states I owned or bought when I was in the UK.

My true first 100% built-by-myself project was an all Russian Reflektor 6C45PI with a 6C33CB triode mono-block tube amplifier. I read an article about a 15-W SE 6C33C-B amplifier that Erno Borbely published in Glass Audio magazine. His article sparked the idea for my own project. I used his design to build my own 6C33C-B amplifier circuit.

“I’m a mischievous youngster! I’m an engineer! I can do much better than him!” So I thought. Well, it didn’t go that well.

SHANNON: What kinds of audio projects do you build? Can you share some of the challenges involved with the designs?

KEN: I build speakers, pre- and power amplifiers, DACs, subwoofers, mains filters, and almost any kind of audio-related gadget. Some of the projects I have built over the years include: Class-D amplifiers with Philips and Tripath integrated circuits, Gain Clone clones (LM3886 and LM1875), Fostex FE167E bass reflex bookshelf speakers out of real wood, a Fostex FE167E in TQWT enclosure, an Altec 640D in Altec 620D cabinet, several 300B SE amplifier variations, 45 SE amplifiers, 6B4G amplifiers, an 1H4G preamplifier, a 6SN7 preamplifier, a 5687 preamplifier, a 6C45PI SPUD, a 5842 SPUD, an EL34 single-ended amplifier, a Tannoy HPD385A active crossover, and many more that I can no longer remember.

I still have some of the completed projects. I’ve also posted a few of them on my website (www.diy-audio-guide.com). DIY audio is challenging in many aspects, especially if you want your designs to sound really good and be reliable. To get something to work is easy. To master it is rather difficult.

Ken used this chassis for a hybrid amplifier design. The front plate and heatsinks are made of aluminum. All the holes are pre-drilled and the chassis accessories are supplied as a package.

Ken used this chassis for a hybrid amplifier design. The front plate and heatsinks are made of aluminum. All the holes are pre-drilled and the chassis accessories are supplied as a package.

Some of the most challenging areas include:

  • Aesthetics—I admit this is one of the challenges I always face. I do see that there are a lot of DIY designs online that look fantastic, almost as good as commercial designs. But for the projects to look good, you need to spend significant time, effort, and money from the design’s start until the end. However, my bias would lean more toward sound than looks. For my projects, I definitely spend more time on the design and the components rather than the finished look.
  • Test and Measurement—This is something I find really challenging on financial and knowledge terms. My daily job includes testing and measuring computer motherboards for power, signal integrity, compliance, eye diagram, and so forth. I use a lot of test and measurement equipment (e.g., multimeters, LCR meters, oscilloscopes, spectrum analyzers, and various other meters). This equipment is expensive and not something an ordinary DIY guy can afford to purchase for personal use. An oscilloscope can cost more than a house in Penang.
  • Measurement Methodology—This is a topic on its own. A different methodology or setup yields different results and that is sometimes misused because end users occasionally deviate from the figures/specifications that matters the most. Audio design is an art. Or perhaps it is better to say audio design is a black art? When I was a young graduate, I thought that if I got the circuit right, good sound would follow. It is not that easy! Everything matters, from component selection to the layout.
    I’m often amazed that some people think tidy wiring equals good sound. This will not guarantee good sound, but it does help future troubleshooting.
  • Separating Truth from Fiction—One thing I personally do not like is trying to differentiate among the hype or claims with hidden/personal agendas. I was, and sometimes I still am, tricked into buying something (DIY parts/components) that does not perform as claimed. There are many out there. So, beware!
  • Last but not least, the biggest challenge for all DIY audio hobbyists is that DIY audio projects often involve carpentry and electrical/electronic, which can sometimes be dangerous. You must work with sharp objects, live electrical connections, and tools. Take precautions and be safe.
Siegfried (Sigi) Maiwald of Wuppertal, Germany, shared his multi-cellular horn project on Ken’s DIY website.

Siegfried (Sigi) Maiwald of Wuppertal, Germany, shared his multi-cellular horn project on Ken’s DIY website.

SHANNON: What has been the most creative project you’ve received on your website?

KEN: I received these two amazing DIY speaker and DIY tube amplifier projects from Siegfried (Sigi) Maiwald of Wuppertal, Germany. One day, I met Sigi via the website’s feedback form and we became good friends due to our DIY audio hobby.

Sigi’s approach to DIY audio, his attention to detail and workmanship, not to mention his energy (and strength to manage such a humongous speaker), and spirit are simply outstanding.
In terms of creativity, he used a broom as the support/stand for a multi-cellular horn! In addition, he used the “УO186” as an inexpensive substitute for the ultra-rare and ultra-expensive RE604, which is definitely cool. I would not have known you could do that. Too bad the project suffered at the end due to a mishap.

You can check out his projects (write-up and photos) at www.diy-audio-guide.com/sigi-audio-setup.html and at www.diy-audio-guide.com/RE604-tube-amplifier.html.

The DIY 300B amplifier circuit design and components use a Tung-Sol 5687WA military tube as the pre-amplifier and driver stage. The power tube is JJ 300B and the power supply uses a RCA 5U4GB full wave rectifier tube.

The DIY 300B amplifier circuit design and components use a Tung-Sol 5687WA military tube as the pre-amplifier and driver stage. The power tube is JJ 300B and the power supply uses a RCA 5U4GB full wave rectifier tube.

SHANNON: With all the products that are available, why do you think audiophiles continue to experiment and build their own equipment?

KEN: DIY audio is one of those continuing trends. Fanned by the increasing price of audio equipment, it remains popular among the DIY-audiophiles. Everyone wants a piece of high-end equipment but the disproportionate price vs. performance and the return of investment places many high-end products out of reach for the general community.

Cost aside (DIY is not inexpensive either!), I’m sure DIY audiophiles will continue to design and build because of the satisfaction and enjoyment they receive when listening to their own creations and masterpieces! I am proud to say that I made most of my home audio gear!

Q&A: Tom Danley

Photo 1: Tom Danley is the Director of Research and Development for Danley Sound Labs.

The Innovator Behind Synergy Horns
Curiosity and ingenuity prove to be a powerful combination

SHANNON BECKER: Tell us a little about your background and where you live.

TOM DANLEY: I grew up in northern Illinois in an area that wasn’t heavily developed, in the same neighborhood where my mom grew up. My brothers and I spent a lot of time outside, playing in the woods and exploring the marsh. We were poor compared to most people in our town, but I wasn’t aware of that until school, when I seemed to be reminded of that regularly. To this day, I have a fondness for wildlife and nature, and I prefer the woods as scenery.

My dad was a DIYer and very mechanical. My parents built a structure that had been used as a chicken coop into the house where I grew up. Dad was very handy, skilled at building things. He had a workshop where I spent time watching him, and eventually I was able to use Dad’s tools.

By about age 12, I knew how to arc weld with Dad’s homemade V-8 powered welder and I had used his metal lathe. At one point somewhere around that same time, I made the transition from taking apart everything I could find to fixing my first radio.

It’s funny. Back then, the garbage man, several neighbors, and some of our relatives brought me broken radios and electronic stuff to take apart. My mom didn’t like my bedroom full of electronic parts and the occasional broken vacuum tubes, and so forth, but she allowed it. Dad was a mechanical guy, but he didn’t like electricity. I think that may have been my secret ally. Mom had an amazing knowledge of the local nature, history, plants, and animals. And a few times, I thought she might have ESP, which as a teen was kind of creepy. In high school, I got my first job in electronics. It was a part-time job at a local TV store called 20th Century TV. I tested tubes on incoming TVs at first, then later I repaired black-and-white TVs and I put new eight-track players and speakers in cars for customers and a couple of car dealers.

While it was my first real job in electronics, I still think of Mr. Reynolds, my boss, as one of the most fair, even-tempered bosses I ever had. At this time, I was in a band playing bass, building loudspeakers and 200-W tube power amplifiers with repair output transformers from Sunn and other parts from Fair Radio.

Several publications of note turned out to be very important in my life. A quick perusal of my bookshelf shows Audio Amateur magazines going back to April 1976, a thick row of Glass Audio and Speaker Builder magazines.

One reason I agreed to be interviewed is that these publications changed my life in a significant way. No doubt there are countless others whose paths were affected by Ed Dell, and I believe strongly that one thing our country needs are more people who do things, experiment, and invent. Trust me, even a guy (myself) who took five years to graduate from high school can teach himself a great deal. An education doesn’t teach curiosity, problem solving, or creativity.

While I have built loudspeakers most of my life and I have occasionally mixed sound, I have also had to have something significant others have helpfully called a “real job” and that was usually in electronics repair. I had built and repaired a lot of electronics by the mid 1970s, and I expected the job at Grommes Precision, an amplifier company, to be an easy “real job.” Funny how wrong one can be. The point being, when you repair something that is broken, you know it is wired correctly but you have one or more bad parts. When you troubleshoot hand-wired tube amplifiers (every one that is produced has to be tested), you find the parts are usually good. If it doesn’t work, anything could be wired wrong—emphasis on anything. Anyway, it was a good experience, a completely different kind of troubleshooting than what I was used to, and I eventually got to work part of the time in engineering, but it was too far away.

In 1979, I worked for a company called DSI that made computer tape readers and punches. These long paper tapes that had the instructions on them were used to program CNC machines back then. At DSI, I learned digital electronic logic repair. Compared to analog, that is simple in operation but large on complexity. Anyway, when I was asked to take a crack at the Kleinschmidt Teleprinters and managed to fix one, that became part of my job. These were very complicated machines and while this made them slightly fun to work on, I grew to dread them too.

Photo 2: Tom Danley is pictured during a payload delivery at NASA’s Marshall Space Flight Center (MSFC), Hunstville, AL.

A co-worker had applied at a small NASA contractor that oddly was right down the street. He didn’t get the job so he told me about it. I applied and got the job at Intersonics, a small company that was trying to do acoustic levitation. That is a non-magical way of suspending an object in midair using intense sound. The idea was, in zero gravity, one could position a sample within a furnace and melt/process it at very high temperatures without any adverse effects from the container. For me, those 17 years were spent in a wonderful environment. One of my bosses was an English acoustician from Mullard Labs who developed the BQS6 sonar transducers. Another boss was a physicist who taught and then worked at Fermi labs.

It was a great opportunity because they really did have sort of a blank sheet of paper and a big list of questions. I was able to find solutions to a number of the problems and I invented a new sound source at 100 times greater efficiency. I became more confident in my work and when I got my first and second patents, I really started to feel like I had overcome my experiences at Deerfield High School.

Eventually, the company grew, I had more inventions, and we flew payloads on several sounding rockets, zero-gravity aircraft flights, and the space shuttle flights STS-7 and STS-51A. My title eventually became Director of Electroacoustic Research. But, the shuttle disaster was the beginning of the end for the company. The work on the space station manufacturing bay stopped and all of that work gradually dried up. I had designed and built large portions of several flight payloads and had the chance to begin astronaut training as a payload support specialist about a year before the accident. I elected not to continue because of my interest in loudspeakers. I wasn’t sure about that decision then, but later I was glad I had made it.

SHANNON: How did you become interested in audio electronics?

TOM: I would say several steps led up to it. Around age 5, I heard my grandfather’s Heathkit mono hi-fi playing a recording that had French horns.  Grandpa lived next door and played a French horn (which didn’t make as big of an impression on me), but I was baffled about how the wooden boxes and his stuff with the little light bulbs (tubes) made the sounds. Also, what eventually became just as interesting, I wanted to understand how the music got into the black discs on the thing I was told not to touch (the turntable).

I did chores for Grandpa and in exchange he bought a Heathkit crystal radio kit for me. I’ll never forget lying in bed with an antenna wire strung around the room and over my bunk bed, listening to WGN while I was buried under my covers. For most of my life, I had a shortwave radio next to my bed as well, which over the decades resulted in a healthy skepticism of our domestic news media. But it was entirely entertaining and awe inspiring for my two young daughters, who shared my fascination with how the radio worked. (I guess they took after their father.)

At about age 7 or 8, my uncle demonstrated an old telephone’s hand-crank generator by giving me a decent shock. That was baffling, how something that felt so strong could be invisible. The shock was a mystery but happened every time. He later gave me the generator. I eventually brought it to school and had my third-grade class hold hands (including me and the teacher) in a circle. It gave us all a mild shock. Electricity was cool!  If you hid the wires carefully, you could even electrify swing set chains turning the swing into something like an ejection seat. (I know from experience, as did the neighborhood kids.)

Another turning point in my life occurred around 1974. After high school, I made live sound speakers for TC Furlong and did the sound mixing for bands. I had a bunch of friends who were going to meet at the club where I was mixing, so I thought it would be fun to record the night on my reel-to-reel tape deck.

I plugged into the full-range output from the board, Y’d it into my tape deck, and flipped the tape at break. When I got home at 3:00 A.M. that night, I was too awake to go right to bed, so I set up the tape and listened to it. I was dumbstruck. At home, it was near record quality. It sounded so different than the live club that I listened to it twice, both sides. What I had on tape was the full-range signal that went to the active crossover, amps, and loudspeakers. It was apparent that the huge difference in sound recorded vs. live was a result of the loudspeakers.

I wouldn’t have guessed it at the time, but each of these events sparked an interest in sound, electricity, and loudspeakers or seemed to have set my compass heading.

SHANNON: What was your first audio technology project? Can you describe it? Is it still in use today?

TOM: The first audio thing I was ever paid for was a pair of speakers I made for my grandfather. When I was about 17 or 18, he commissioned me to build a pair of speakers for his basement. I made many pairs of loudspeakers and a couple sound systems in the 1970s, but I doubt any of them still exist. My first successful commercial loudspeaker product was in the 1980s.

During an airplane trip, I was paging through a surplus catalog when I thought of trying to use a surplus low-inertia DC servomotor to replace the voice coil in a woofer. One motor caught my eye, and I had seen two of them at the local surplus store, Harrison Supply. When I got home, I went and bought them for $12 each.

My third prototype sounded good enough to bring to work and demonstrate. My bosses were both impressed, and Roy, who was a hi-fi buff and World War II acoustician from Mullard Labs, later told me I could start a small loudspeaker division in the shop as long as its only cost was space and lights. I had some “cred” by then with Roy, who knew I had hand built electrostatic speakers, and he asked me to disable the protection spark gaps in his ESL-63s. (They sparked at just the wrong times.) Very hesitantly I agreed and took them home to take apart and “fix.”

The servodrive woofers we made there were used for special effects at Disney World, the Mirage casino’s volcano, and the “low end” for tours for Michael Jackson, U2, Garth Brooks, Def Leppard, and so on. While these were much more powerful than conventional subwoofers, the motors were remnants of the computer tape memory era, and when they were no longer needed, the price for the motors skyrocketed them into extinction.

SHANNON: Tell us about your company, Danley Sound Labs, and the role you play within the company. To what do your attribute your company’s continuing success?

TOM: I credit my associate Mike Hedden (Danley Sound Labs president/CEO) with much of the company’s growth. And he followed a very logical but nontraditional path to expand the company. I am blessed to have him as my co-worker and friend. As for my part, I invented and developed the technologies we use, including the Synergy horn, the Tapped horn, the Paraline, the Shaded Amplitude horn, and the Layered combiner. I also designed most of the products that use them.

Actually those things are a small part of what a company does. A good idea on its own is something like a one-legged table (not that useful on its own). While my job is the most fun (I think), when I send my drawings to Tom Wilson, our CAD guy, he figures out the easiest/best ways to make the product. After a final look, his 3-D CAD drawings are sent to the cabinet shop where the CNC machines get programmed based on those drawings and so on. Early on, I may make a prototype or mock-up a part of it to test, but the very large cabinets are too complicated to build at home.

Our success? Again, it is a number of things acting together, a synergy. The team Mike has assembled including  Ivan Beaver, Chad Edwardson, Tom Wilson, and Doug Jones, and so on are people who are passionate about sound. Some years ago for a trade show, we had T-shirts made that said: “Sit down and listen. It’s about the sound, it’s why you got into audio.”

For my part, the team members have more of an idea what they need to do than I do. When they tell me what they need, it is more an outline of what a product needs to do. The “how and what” part is entirely up to me. I like to say that the better I see the target, the more likely I will be able design something to hit it. The best part is no one says you have to do it this way or that way. I can design and test whatever I imagine, as long as it gets the job done.

Sonically, Synergy horn’s success is simple but one has to hear it. It is a way to combine more than one driver in more than one frequency range into a single, constant directivity horn with the appropriate crossover. The outcome literally appears to be, measures like, and sounds like a single crossover-less driver.

That sounds simple, but it is surprisingly hard to do. An example of its effect is that you can walk up to the speaker, move around, literally even put your head deep into the horn mouth of a three-way Synergy horn, and never hear any clue there is more than one driver. Many of them can even reproduce a square wave over a broad band, even with a passive crossover. In large-scale sound, this sounds dramatically different than the concert-style arrays.

SHANNON: You hold 17 patents on a variety of acoustic and electromagnetic devices. Where do your ideas originate?

TOM: Well, there are a couple new ones to add. To be current, the Tapped horn, Synergy horn, Paraline, and Shaded Amplitude horn have been issued, and the Layered combiner will be soon.

As to where they come from, I can try to describe the process.  It begins with a problem to solve. The best solutions come when you find the simplest answer whose form is driven by the problem and conditions. With the Synergy horn, for example, the solution should have constant directivity, and it should act like one source in time and space so it will not have lobes and nulls in its dispersion pattern.

Sometimes solutions to these issues happen in a flash, sometimes it takes months to work out a solution. The Layered combiner used in the J-series horns was the hardest loudspeaker design I have worked on so far. It took four months to get from a fleeting mental image of “I think I see how” to a drawing that could be built.

SHANNON: Can you describe one or two of your inventions?

TOM: Thirty years later, I still get a kick out of acoustic levitation. Using high intensity sound you can position/levitate an object in midair. In the 1990s at Intersonics, I demonstrated acoustic levitation for a movie called “Mystery of the Sphinx.” If you visit www.youtube.com/watch?v=NhDmCuffwOI, the scene is about 50 min into movie.

If you Google “Argonne acoustic levitation,” you can find a link to a recent video demonstration using the levitation sound sources I developed.

Photo 4: Tom Danley’s Synergy and Tapped Horn loudspeaker system design can be found in the Chicago’s Museum of Science and Industry’s IMAX theater.

My inventions include the Synergy and Tapped Horn systems, and Shaded Amplitude Synergy horns. The Synergy and Tapped horn system is used at some of the large Omnimax to Imax conversion theaters.

The Shaded Amplitude horns are the “things” that look like birdhouses that overhang the edge of the balconies at Turner Field in Atlanta, GA. With the Shaded Amplitude horns, energy projected to the front row is much louder than that projected directly below, so the measured sound pressure level (SPL) only varies about ±1 dB over the seating area.

SHANNON: Which of your inventions would you describe as a “game changer” in your field?

TOM: My “game changer” would have to be the large J-series Synergy horns.   In the stadium sound area (e.g., football- and baseball-sized venues) it is most difficult to get good sound.

Photo 5: Shaded-amplitude Synergy horns are shown overhanging the balcony at Atlanta’s Turner Field.

It is also an area where the decision makers don’t care about brand identity or who tours with X, Y, or Z speakers. There are no live-sound style riders and basically the only thing they care about is getting better sound. So for a company like ours that doesn’t do a lot of marketing, this is a level playing field. The concert systems that evolved for that market may be the best they know how to make, but they radiate an interference pattern you can hear if the wind blows. Every location has a different sound and radiate sound in the wrong directions. When you can eliminate all that interference, radiates enough acoustic power with one single source, and have more directivity, then it becomes a pretty obvious sonic choice. It’s as close to hi-fi as you can get on a grand scale.

The familiar large sound systems are a huge array of sources, which depend on DSP, and sound worse the larger they are. The Synergy horns work because the source is acoustically correct at the origin.

SHANNON: Do you have any inventions that might soon be released?

TOM: Oh, now that wouldn’t be fair. But, at InfoComm 2013 (in June), we introduced a new stadium-sized Synergy loudspeaker with a working distance of 1,000’ that  utilizes more than 100 drivers acting as one source.

SHANNON: Where does your affinity for low frequencies originate? What makes them so appealing to you?

TOM: At about age 9, I remember helping my grandfather clean up after a service at our church. I used to explore the building and on a previous visit I found a ladder in a back closet that led to the organ pipe loft where I found a confusing maze of tubes and pipes. Very complicated plus wires plus sound equals very interesting to me. I was especially interested in the device after hearing about a time when the organ’s blower motor failed. The organist banged on the floor and my grandfather and two other church members managed to turn the shaft with their feet enough for her to play weakly. As a child, I loved fans so this was already cool.

That day, I spied the organist coming back to practice and, being curious, I snuck into the pipe loft. In that room, the pipes—rather the sound—shook my body. I didn’t know if I should run or stay perfectly still. Nothing was moving or otherwise scary, there was just the intense sound, so I stayed and listened for a while. It was by far the loudest musical experience of my life for a good number of years.

SHANNON: Where do you see the audio industry in 10 years?

TOM: In a way, the direction some of the industry has gone is disappointing. I would have given a great deal to be able to record like you can now with even a MI grade recorder, yet there are fewer bands. And, there are even fewer bands that can play well live or even have people who are interested in playing instruments. Like many industries, the home audio market is so focused on profits that fantastic technology goes unused, and many companies have lost focus on the need for high-quality audio products. Great progress exists for measuring and DSP products but often the companies are more focused on profits than  the advancement of the art.

In the late 1990s, I brought a state-of-the-art TDS measuring system that was the size of a suitcase and the weight of a car battery to Egypt to measure the Great Pyramids’ acoustics for a movie (www.livesoundint.com/archives/2000/julyaug/pyramid/pyramid.php). It was a serious armload to carry. Now, you can perform many more measurements and do them faster using an iPad and an interface.

As for me, I would say we still have a ways to go before you can be reliably fooled by a reproduced sonic “environment” or even being able to capture a remote environment. If you include a loudspeaker in a simple “old-time” generation loss recording test, even an anechoic one (where there is no room contribution), you find even good loudspeakers—unlike any other part of the chain—only go a few generations before sounding bad. I hope the industry eventually puts more emphasis on sound quality, the recording industry ends the volume wars, and the listeners win. Keep building. aX

April New Products and News

AmpliVox Wireless PA Supports many Media Devices

Amplivox SW720 Wireless PA system

The updated SW720 Wireless PA system includes several practical accessories.

AmpliVox Sound Systems has unveiled its newly updated SW720 Wireless PA system, a versatile PA package that supports all types of external media. The SW720 PA enables audio or video to be played from MP3s, CDs, DVDs, or any iDevice from Apple (e.g., iPhones, iPads, or iPods), complemented by a wireless handheld mic for voice amplification. For audiences of up to 500 people and rooms as large as 2,500 ft2, the SW720 is an all-in-one solution for multimedia presentations.

The revamped SW720 Wireless PA system with a remote-controlled DVD player now includes AmpliVox’s S1732 cable and adapter, enabling iPads and other Apple devices to be simultaneously played and charged. The unit also contains an integrated DVD/CD/MP3 disc player with a USB/SD card reader and video output that enables DVDs to be viewed with a projector or other video display. For voice amplification, the SW720 features a built-in UHF selectable 16-channel wireless receiver with a 300’ range wireless handheld microphone.

The SW720’s straightforward controls customize presentations. A voice priority switch mutes music when the mic is in use, and separate bass/treble controls enable easy sound adjustments. Weighing 11.5 lb, the molded plastic enclosure is durable and portable. A protective cover offers many pockets for accessory storage. The SW720 can run for up to 6 h on its built-in rechargeable battery, or it can be powered with the included AC power cord.

For more information, visit www.ampli.com/ipod-pa-system.

Dayton Audio’s DVC Subwoofer

Dayton Audio Ultimax DVC

Dayton Audio’s DVC subwoofers are designed to improve power handling and reduce power compression.

Dayton Audio’s Ultimax Series DVC subwoofers are purpose-built to move air and create clean, articulate, and fast bass. To improve power handling, increase thermal management, and reduce power compression, Dayton Audio designed the Ultimax Series with large black anodized formers and vented pole pieces, under-spider ventilation, and two-layer copper voice coils.

The Ultimax’s “Tall-Boy” rubber surround is intended for extra-long linear excursion without reducing the Nomex honeycomb/woven glass-fiber laminated cone’s surface area. Copper shorting rings and a pole piece cap reduce inductance and distortion, while the Ultimax’s dual spiders maintain linearity at high drive levels.

Dayton Audio’s Ultimax Series dual voice coil subwoofers are engineered and built using the latest in subwoofer technology. They are now available in 10”, 12”, and 15” sizes. Dayton Audio products can be purchased in the US through Parts Express (www.parts-express.com).

For more information, visit www.daytonaudio.com.


Danley Sound Labs SH-96 HO

Danley raises the sound pressure level (SPL) on its Synergy Horns SH Series

Danley Sound Labs recently announced improvements to many of its already highly-regarded SH Series full-range loudspeakers. The new versions are identified by the suffix “HO,” which stands for “high output.” For example, if someone wants to get the most performance out of the Danley SH-96, order the Danley SH-96 HO.

The new designs use a more powerful two-way high frequency. As a result, the low- and mid-frequency drivers can be used to their full potential yet maintain Danley’s characteristic frequency response, phase response, and fidelity. In conjunction, the HO designs use a new crossover and have additional options for bi-amping and for changing the low-frequency impedance. Because the cabinets themselves haven’t changed, the new versions retain the coverage and frequency loss patterns of the originals. The new models include the SH-95 HO, the SH-96 HO, and the SH-64 HO.

Because the new switch panel cannot operate reliably if left exposed to the elements, weatherized versions of the new high-output loudspeakers must be pre-ordered with specified biamping and impedance settings.

For more information, visit www.danleysoundlabs.com.

B&K Precision Launches “pwrApp” for Apple Products

B&K Precision pwrApp

B&K Precision’s new “pwrApp” can be used on an iPad, an iPhone, and an iPod touch.

B&K Precision launched its new “pwrApp” for iPad, iPhone, and iPod touch. Adding greater value to its DC power solutions, B&K Precision’s pwrApp enables full monitoring and control of a network-connected (via WLAN) XLN-GL series of power supplies over local wireless networks.

The pwrApp’s primary function is remote operation of all XLN-GL power supplies’ functions. The pwrApp’s features include live visual monitoring and interactive power supply control, visual data graphing, audible trigger alarms within the app, and data export.

Fully functional in-app demos of devices, monitoring, and programs are available with or without a connected XLN power supply. B&K Precision’s pwrApp for iPad and iPhone offers full interface control in English, French, German, Portuguese, Spanish, and traditional Chinese via a simple selection menu. Future versions of pwrApp will offer control of additional select WLAN-enabled B&K Precision power supplies. Available for immediate download via iTunes, pwrApp is free of charge to all users.

For pwrApp and XLN information, as well as hardware/software requirements, visit www.bkprecision.com/pwrapp.

NUGEN Audio offers Stand-Alone LM-Correct Loudness Tool

NUGEN Audio LM Correct

NuGen Audio now offers a new stand-alone version of its LM-Correct loudness analysis and correction tool.

NUGEN Audio, a creator of intuitive tools for audio professionals, has released a new stand-alone version of its LM-Correct loudness analysis and correction tool, which was originally only available as an AudioSuite plug-in. For the first time, LM-Correct is available as a file-based program, taking its speed and simplicity beyond the Avid digital audio workstation (DAW) environment. LM-Correct provides EBU R128|ATSC A/85 (CALM Act)-compliant loudness correction with unmatched simplicity, providing users with a rapid two-click solution for loudness normalization and conformance.

Part of NUGEN Audio’s range of innovative and easy-to-use loudness correction tools, LM-Correct is a faster-than-real-time tool that calculates and corrects for integrated program loudness and short-term maximum loudness. LM-Correct includes an internal true-peak limiter that transparently handles any intersample peaks.

LM-Correct’s settings include presets for current loudness standards, short-term loudness, overall integrated program loudness measurement and correction, maximum true-peak level targeting, and “EBU Mode.” The software also supports mono through 5.1 audio.

LM-Correct is available immediately for OS X and Windows operating systems. For more information about LM-Correct and other NUGEN Audio products, visit www.nugenaudio.com.

Saelig Introduces Handheld RF Spectrum Analyzer

Saelig PSA2702

Saelig’s PSA Series II RF spectrum analyzers feature long, rechargeable battery life.

Saelig Company has introduced the PSA Series II RF spectrum analyzers. Available in 1.3- and 2.7-GHz versions, these new instruments are smaller, lighter, and have a longer battery life than other more expensive handheld RF products. PSA Series II analyzers incorporate a 4.3” (11 cm) backlit thin-film transistor (TFT) color touchscreen display, with a high-capacity rechargeable Lithium-ion battery to produce more than 8-h operation per charge. The PSA Series II PSA1302 has a 1-to-1,300-MHz frequency range, while the PSA Series II PSA2702 operates up to 2,700 MHz. Dynamic range is 80 dB with a noise floor at –100 dBm. Resolution bandwidth is selectable down to 15 kHz.

The PSA Series II’s features include sweep modes (e.g., continuous, single, peak hold, and sweep average), AM/FM audio demodulation with built-in speaker, and data logging for traces, data points, or screen images (with storage for 10,000 entries per file triggered from a key press, internal timer, external trigger, or the limits comparator). Traces or complete screen images can be saved to file and compensation tables for antennae or other external transducers can be created and loaded. USB host and device connectors enable the use of USB flash drives or direct connection to a PC.

PSA Series II analyzers are controlled via finger-operated touchscreen soft keys in a hierarchical menu system that provides rapid access to menu functions. All functions can also be operated using just the hard keys.

The ruggedized casing incorporates a rubber protection buffer, a bench stand, and screen protection. For bench-top use, the instrument can be operated from its AC charger. For portable use, its 8-h battery life can be further extended by selecting auto-off, which turns the instrument off (retaining all data) after a selectable delay of 5 to 60 min. from the last key press. The compact, handheld PSA Series II RF Spectrum analyzers weigh 20 oz, making them suitable for any portable RF service kit. For more information, visit www.saelig.com.