Audio Update

We’re now a month into the new year. What types of audio projects have you designed and installed? We’re interested, so send us an e-mail with “audio update” in the subject line and include details about your latest project. We’re interested in tube projects, DIY speaker setups, hi-fi product reviews, and more.

If you haven’t decided on your first 2013 project, you’ll likely get some excellent ideas from this issue. We feature audio product reviews, speaker design tips, and more. Let’s look at the details.

On page 8, Mike Klasco and Steve Tatarunis deliver the second article in their series, “Tweeter Talk.“ They present different tweeter styles and cover the balanced drive tweeter.

Turn to page 12 for Gary Galo’s review of Wyred 4 Sound’s µDAC USB D/A Converter. He covers its features  and sound.

The third “session” in Richard Honeycutt’s “Speaker Design School” series begins on page 16. He details “the nuts and bolts of speaker design.”

Even if you attended CEDIA 2012, check out David J. Weinberg’s thorough review of the expo on page 20. He presents information about the innovative sound processing, speaker, headphone, and technologies that were on display.

If you’re an electric guitar player, you’ll enjoy Chuck Hansen’s review of Helmuth Lemme’s book, Electric Guitar: Sound Secrets and Technology (Elektor 2012).

On page 29 you’ll find an interview with loudspeaker expert Charlie Hughes. He highlights his audio interests and describes some of his past and present projects.

The third article in Richard Honeycutt’s series “Power Supplies for Hollow-State Equipment” appears on page 34. He covers power, tube selection, and more.

Vance Dickason wraps up the article portion of the issue with a look at the Motus UH25CTi. You’ll find it’s an interesting high-frequency dome tweeter.


C. J. Abate

Audio Crossword Answers (February 2013)

The answers to audioXpress’ February audio crossword puzzle are now available.


1.    DISTRIBUTEDMODE—A loudspeaker that is not typically capable of the high sound levels required for performance audio systems [two words]
3.    FEEDBACK—A capacitor used in an op-amp circuit
4.    INTERFACE—An electrical circuit that links more than one device
6.    CROSSTALK—Caused when one circuit’s signal creates an unwanted effect on another
8.    TACTILETRANSDUCER—Converts electrical signal into vibration [two words]
10.    DIRECTIVITY—An acoustic source’s behavior in a 3-D space
12.    FERRITE—A magnetic material used in a driver’s construction
13.    PIEZOELECTRIC—Charge that builds up in certain material due to mechanical stress
15.    THREEDIMENSIONAL—An acoustic passive radiator diaphragm trait [two words]
16.    HAFLERCIRCUIT—Mimics matrix decoding’s effects without using expensive electronics [two words]
17.    OEB—An Italian loudspeaker component supplier
18.    LINEARRAYS—Speakers with a horizontal directivity equal to that of each driver [two words]
19.    PATENTAPPLICATION—New inventions are published in this journal [two words]
20.    HUMREDUCTION—Use a bridge rectifier driven from an 8- to 12-V transformer winding, a capacitive filter, and a three-terminal IC voltage regulator to achieve this [two words]


2.    BLEEDER—A resistor that draws the critical amount of load current
5.    FILAMENTS—Often supplied by AC voltage from a transformer winding
7.    SHUNTREGULATOR—Stabilizes voltage fluctuations [two words]
9.    SURFACEMOUNTED—Method that places components directly on PCBs [two words]
11.    INCOMINGSTEREO—A signal that is detected by “true” sound decoders [two words]
14.    OSCILLATION—Doesn’t remain in one place

Member Profile: Garth Wasson

Garth Wasson

Garth Wasson

Location: North Vancouver, British Columbia, Canada

Education: Garth has a BA and an LLB from the University of British Columbia and a certificate from King’s College London University, London, England.

Occupation: Retired barrister and solicitor (a lawyer)

Member Status: He has subscribed to audioXpress since 2005.

Affiliations: He currently holds no official memberships with any audio organizations.

Audio Interests: Garth said he is most interested in classical music.

Most Recent Purchase: A digital multimeter that measures inductance and capacitance

Current Audio Projects: Garth said he has just completed two 100-W, push-pull El34 amplifiers with output transformers that Doc Hoyer designed and built.

Dream System: He said the system would include a couple 100-W amplifiers with a good preamp, a good turntable, and Klipsch horn enclosures. He would also add a quality FM tuner, digital inputs, and a large TV with good sound input. Garth said he doesn’t care too much about surround sound, but he admitted that he does have a couple 50s he could use with his dream system.  “Obviously, I would want two more Klipsch horns there, too,” he added.

Q&A: Ron Tipton

Ron Tipton

Photo 1: Ron Tipton tackles a project in his home work space.

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

RON TIPTON: I was born in Chicago, IL, and by the age of eight, I was spending many Saturdays haunting the exhibits at the Museum of Science and Industry with friends. I suppose that was an indication of where my main interests lay. We moved to Kansas City, MO, when I was 10, and I had to content myself with scientific books and magazines: no science museums. I moved to Las Cruces, NM, in 1956 to attend what was then the New Mexico College of Agriculture and Mechanic Arts as a junior in the Electrical Engineering department. (The college became New Mexico State University in 1960.) I did pick up a couple of EE degrees, but I didn’t complete my doctorate because of business. I started Testronic Development Laboratory (TDL) in 1957. Except for a few years in northwest Arkansas (more about that later) and back in Kansas City for a while, I’ve lived in the Las Cruces area since 1956.

SHANNON: Describe your career as an electrical engineer and your job at White Sands Missile Range.

RON: In the early 1960s, the telemetry (radio transmission of data from an air- or space-borne vehicle back to the ground) band was around 220 MHz. There were a number of reasons, including smaller antennas, to move the band to 2,200 MHz. I was part of the project to accomplish this move. These were the days of vacuum tubes, so designing and building a transmitter was a big challenge because any vibration in the missile (there was a lot of it) vibrated the tube grids causing frequency modulation of the output, which had to be very low to be acceptable. Several contractors tried and failed but one, Microdot, was successful. It was a big day when we flight tested the transmitter on a missile and it worked fine. Now, of course, the transmitters and receivers are all solid-state and reliable operation is taken for granted.

Most of my other work was with various passive tracking systems. Unlike radar, which is an active tracking system, passive systems use the emissions from the vehicle, usually the telemetry transmitter, to perform the tracking. This usually requires a ground-based antenna field, because they are phase and phase-difference measuring systems, so they benefited from the smaller antennas at 2,200 MHz. By knowing the antenna spacing and the telemetry transmitter carrier frequency, data was collected that was later converted to a track by computer analysis. I retired in 1995, so with the increases in computer performance real-time tracking is probably used today.

The telemetry transmitter’s carrier had to be very stable for this to work. The various detection oscillators in the ground-based receiver were set so the output to the tracking system was usually 5 kHz. The usual phase detectors were period counters. The track data 5 kHz started a high-frequency counter and the reference 5 kHz stopped it so there was some ambiguity in the count. I designed and built a very precise 5-kHz autocorrelation phasemeter using a Motorola DSP56156 digital signal processor. This resulted in 1,700 samples per cycle with a phase measurement resolution of 0.212° with a corresponding lower tracking error. I have never followed up on it, but this technique could be used to design a very precise audio phasemeter.

SHANNON: How did you become interested in audio electronics?

RON: I think it was a result of my love for music. In the early 1950s, I bought an inexpensive 33-1/3/45-rpm turntable, and I needed a preamplifier and power amp to use it. I decided to build them so I found a combination preamp, low-power amplifier in some book. I bought all the parts from Burstein-Applebee in Kansas City, built it, and it worked fine. It used vacuum tubes, of course. I was hooked.

SHANNON: Can you tell us about your work with active filters and pseudo-random noise generators? Do the models you used then still function today?

RON: By the mid 1960s, useful op-amps were available—in particular the LM741 general purpose, the LM301A for better performance, and the higher frequency NE531. It was practical to design and build active filters using either the voltage follower or multi negative feedback topology. I built them in potted modules and as plug-in cards. I had several orders for sets of third-octave bandfilter cards that exactly fit a Hewlett-Packard audio spectrum analyzer. I sold them for less than the HP price! I still have a few of the potted module filters and they work just as they did 50 years ago. Two 50-year-old active filter modules are shown in Photo 2.

Photo 2

Photo 2: Ron built these two active filter modules 50 years ago. The left-hand unpotted module is a tunable low-pass filter as part of the GMS piano tuning aid.

The left-hand unpotted module is a tunable low-pass filter mentioned in the next question as part of the GMS piano tuning aid. It is 2” square to give you an idea of its size. The six gold-plated brass terminal pins extend about 0.2” out of the epoxy potting material to make the electrical connections to the circuit.

The first pseudo-random (P-R) noise generator I designed and built, the model 105, used RTL logic. This was an early logic family in standard DIP packages. I didn’t sell even one of them but it was an interesting learning experience! Next came the model 108, which used 7800 series TTL logic. The 108 and its variants (i.e., the 108-M4, 108-M5, 109, and 111) all sold fairly well.

Perhaps I should mention that P-R noise is just random noise within each sequence but the sequences exactly repeat with the sequence length dependent on the shift-register length and the clock frequency. Thus, we have a random signal with a known period just like a sine or square wave. My article: “Audio Testing With Noise,” Voice Coil, December 2010, discusses P-R noise details.

The 108-M4 and 108-M5 were both “gated” generators. They could put out a noise burst with the duration and repetition rate set on the front panel or triggered by a pulse from a remote location. These were both custom models designed to meet the customer’s needs. This was economical for the customer because the 108-series all used the same size plug-in circuit cards with each card performing a certain function: clock generation, shift-register, gate generator, and so forth. The cards could be “mixed” to provide the required performance. You can find more on this topic, including photos, in the Voice Coil article mentioned earlier.

Photo 3

Photo 3: A typical plug-in card is used to perform a certain function (e.g., clock generation, shift-register, gate generator, etc.)

Photo 3 shows a typical plug-in card. They measure 4.6” wide by 4.7” high.

SHANNON: What kind of audio products did you build for GMS? Can you share some of the challenges involved with the designs?

RON:  I designed two lines of guitar amplifiers for GMS and both were marketed by Gretsch. The lower-cost line was the Broadkasters about which I don’t remember much or have any documentation. The premium line was the Nashville series, which included the Pro-Lead, Pro-Steel, and the Pro-Keyboard models. These were rather straight-forward designs with a few exceptions.

The reverb units were mechanical springs in a metal housing with a small loudspeaker without a cone driver at one end and an inductive pickup coil at the other end. I needed some power to drive it because there was quite a bit of loss in the spring, which was about 10” in length. I designed a small power amplifier in a potted module with an aluminum baseplate to transfer the heat to the amplifier’s chassis. A circuit diagram and photo can be found at

The Pro-Lead model had a tremolo circuit, which was also built as a potted module because Gretsch wanted to keep the circuit under wraps. It had rate and intensity controls on the front panel, a foot-switch jack to turn it on and off, and an LED that illuminated when it was on. I thought it was a rather clever design at the time. Details can also be found on my website.

The Pro-Keyboard had what we called an Accent module which was controlled by a three-pedal footswitch which enabled the musician to instantly change the volume. I though this design was rather innovative because I used the three pedals to get five levels of volume change by sensing how deeply the pedal was depressed. This circuit was also built as a module to hide the design. It used a 4066 analog switch to change the gain of an LM301A op-amp. The other logic chips just decoded the foot pedal positions to control the 4066. The circuit diagram for this design can also be found on my website.

In addition to the guitar amps, I designed a digital piano-tuning aid for the Baldwin grand piano manufacturing plant in Conway, AR. It was a box that produced the 88 piano notes through a built-in 6” speaker. The note to be played was selected by a row of 12-note push buttons and a row of eight octave push buttons or by a two-pedal foot switch, one pedal for the octave and the other for the note. There was also a front panel rotary switch for the normal equally tempered scale, a quarter semitone high or a half semitone high. (Pianos were often tuned slightly high so the structure could settle into the proper tuning.)

The heart of the piano-tuning aid was a 4059 programmable frequency divider, also called a divide by N divider where N was an integer number and the output frequency was the clock frequency divided by N. The integer numbers, N, were read from a PROM. The 4059 output was a square wave which contained too many harmonics to be useful in tuning a piano. (The person doing the tuning matched the output of the piano-tuning aid to the piano note by tightening or loosening the tuning pin.) So I needed to low-pass filter the output. I did this with a frequency-to-voltage converter whose DC output voltage controlled the cut-off frequency of a voltage tunable low-pass filter. The output was a sine wave because the filter’s cut-off frequency tracked the output frequency. I considered this one of my more interesting designs! (The F to V converter and the tunable low-pass filter were potted modules to conserve space and all of the logic chips used were RCA 4000-series CMOS because RCA was a major supplier to the Baldwin Piano and Organ at that time.)

SHANNON: You have been TDL’s founder and principal designer for many years. What has been your best experience?

RON: I think the most interesting task was designing the “Hot Strings” guitar for Chet Atkins. (It was marketed by Gretsch as the “Chet Atkins Super Axe.”)  This project is fully described in my article: “Designing the ‘Hot Strings’ Guitar for Chet Atkins” (Multi Media Manufacturer, May/June 2006). But I’ll recount some of the highlights.

Chet heard about my modules in the piano-tuning aid so he came to the GMS plant in the fall of 1975 to discuss the idea of putting some effects modules inside the guitar body. We finally settled on a compressor (2” × 2” × 0.5”) and a phaser (2” × 3” × 0.5”). By the end of August 1976, I had an assembled guitar ready for trial. Chet came to Prairie Grove about mid-September to give it a try. He was generally pleased with the performance, but he wanted a couple of changes. This was also the time he picked the “Hot Strings” name. We made the changes and my final set of drawings is dated January 19, 1977. I’ve never seen a production Super Axe, but I do have several photos.

The rear cover of RCA Records LP APL1-2786 (1978), “Chet Atkins and Les Paul: Guitar Monsters” shows 12 photos of Chet and Les. This guitar can be clearly seen in five of them.

Through the years, I’ve heard from several owners of a Super Axe and replacement modules are now available from the TDL website.

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

RON: My first personal project was the mono phono preamp/power amp I mentioned previously. No, it’s not still in use, and I have no idea what happened to it.

SHANNON: You wrote an article, “A Vintage Turntable Revisited,” in audioXpress, September 2012. Why did you think it was important to revisit it?

RON: The revisit was important because of the carbon fiber tube tone arm which let me lengthen it and thus, reduce the tracking error. While it is true that this resulted in a rather large turntable, I think it was worth it. It is still much in use because it sounds very nice.

SHANNON: Can you share the details on some other personal audio projects?

RON: I usually have quite a few projects going at the same time, but I’ll talk about two of them that may be of interest.

I’m building a stereo pair of three-way speakers, that is, three inputs: base, mid-range and upper frequencies (see Photo 4).

Photo 4

Photo 4: This will be a stereo pair of three-way speakers. The three inputs will be: base, midrange, and upper frequencies, once Ron completes the project.

These will be sealed enclosures and you can see the internal bracing in the photo. The front and rear panels are 13-ply Baltic birch with 0.75” MDF for the sides, top, bottom, and braces. The box was computer designed for all Dayton (Parts Express) drivers. The top and bottom “holes” are for the 8” reference-shielded woofers (295-366), the next two holes toward the center are for the 2” dome midrange (285-020), and the center hole is for the 0.75” neodymium dome tweeter (275-035). The tweeter is rear-mount, but I have solved that construction problem! The seams are caulked, the black patches on the inside walls are barium-filled vinyl for sound absorption, and the woofer and midrange drivers have T-nuts installed for their mounting screws.

I have built active crossovers, each with the required three outputs, but a Behringer DCX2496 can also be used. The performance comparison will be interesting. Yes, it does require six power amplifiers, but that’s not such a big deal these days even though it would be best if they were all the same type. The simulated overall frequency response looks good.

Some of my projects are studies and they are difficult to describe or to photograph until finished. It’s also difficult to photograph a construction project for which I have all the material, but I haven’t started putting it together yet. So I’ll just tell you what it’s about.

As some of you may know, my company, TDL Technology builds audio equipment for sale. We do a 100-hour burn-in for quality control so our failure rate is nearly zero. But I’ve wondered about doing more. What about bad solder joints or microphonic parts (rare, but possible even with solid-state parts)? It occurred to me that a vibration test might be useful but commercial shake tables are out of my budget. So, what about building one?

The top surface to which the device under test will be fastened is a piece of 20” × 12” × 0.5” thick piece of ceramic tile cemented to a 20” × 12” sheet of 0.75” 13-ply Baltic birch plywood. On the underside of the plywood, two Aura Pro Bass Shakers (Parts Express 299-028) are mounted and wired in series. This composite platform will be supported above its heavy base at its four corners by 0.25” diameter rods and neoprene vibration isolators (McMaster-Carr 94955K31). The device under test will be attached to the top surface with cotton webbing belts fitted with ladder-lock buckles. Accelerometers (Measurement Specialties ACH-01) will be cemented to the top surface and mechanically attached to the device under test to monitor the vibration level.

The Shakers have a frequency response of 20 to 80 Hz so a low-pass filter will be used at the output of the noise generator. I expect white or pink noise will be the most useful. It’s possible that it would also be a useful subwoofer!

SHANNON: You have done a lot of work with audio restoration. Why do you think it is important?

RON: Personal (home) restoration is important because it’s fun and because the music needs to be saved. Record companies have released a tremendous number of records in the past 100-plus years and a few have been remastered and rereleased—a very few. Record archives do their best at restoration but many collections are very large and funds are always limited. I think it’s up to amateur restorers to do as much as possible.

SHANNON: We went from vinyl to cassette to CD to DVD to music servers. What do you think the next audio format will be?

RON: I hope the next big breakthrough will be holographic recording—but we’ll have to wait and see.

SHANNON: What do you see as some of the greatest audio innovations of your time?

RON: The invention of solid-state electronics is at the top of the list. It changed our world. And, I don’t mean just the transistor. LEDs and solid-state lasers made possible so many innovative audio products.

SHANNON: Do you have any advice for audioXpress readers who are thinking of building their own sound systems?

RON: I’ve been building most of my own audio equipment for more than 60 years so it’s possible that I’m prejudiced. As I sit here writing this I can see 10 different power amps and three different phono preamps that I’ve built. Getting into building your own can be addictive so beware! But if you have the inclination and the means, go for it! You will also learn a lot in the process, not only about audio techniques but also how to properly do the construction.

Industry Watch: January

Nortek Experiences Gain
Most of this month’s industry news is financial and not much of it is all that good. However, Nortek, parent of multiple residential and commercial systems brands (e.g., Aton, Elan, Niles, SpeakerCraft, Sunfire, and Xantech), is the exception. It posted a second consecutive quarter of net profits, but the figure was small. In its fiscal third quarter, Nortek posted a $4.7 million net profit compared with a year-ago $2.1 million loss. Its second quarter net profit was $18.5 million compared with a year-ago $31.9 million net loss. The first-quarter net loss was $1.2 million. In fiscal 2011, Nortek posted a $55.9 million net loss following a 2010 $13.4 million net loss. This fiscal year, third-quarter revenues were up 1% to $557.4 million and its operating income surged 141% to $33.8 million. Nortek provides products to the U.S., Canada, and Europe.

Logitech Sees Drop in Sales
Logitech International sales were down for its fiscal second quarter, which ended September 30, 2012, but its operating income and net income were up. Sales for the quarter were $548 million, down 7% from $589 million in the prior year. Excluding the unfavorable impact of exchange rates, sales were down 4% compared with the same quarter in the prior year. Sales were down 14% in its audio segment, 17% in its video segment, and 31% in its digital home segment. The digital home decline could be attributed to the company discontinuing sales of its Google TV peripherals. Operating income was $24 million, up 3% from an operating income of $23 million in the same quarter a year ago. Net income was $55 million versus last year’s $17 million. Net income for the quarter includes a net tax benefit of $32 million from the closure of an income tax audit. Logitech’s retail sales decreased by 5% year over year. They were down 3% in EMEA countries, 6% in the Americas, and 7% in Asia. OEM sales decreased by 27% and sales for the LifeSize division decreased by 7%.

Net Sales Down for h.h. gregg
h.h.gregg reported a 5% drop in net sales and lower net earnings for the second quarter, which ended September 30, 2012. Net sales for the quarter decreased to $587.6 million, from $618.6 million in the comparable prior year period. The decrease for the three-month period was the result of an 8.8% store sales decrease along with the lapping of strong grand-opening sales performance from stores that opened in the prior fiscal year, partially offset by the net addition of 19 stores during the past 12 months. Net income was $3.8 million, down $6 million for the comparable prior year period, a result of a decrease in store sales, an increase in net advertising expense as a percentage of net sales, an increase in SG&A expense as a percentage of net sales, and other factors, h.h. gregg said.

McMagic to Revive Vann’s Line
Vann’s, the bankrupt consumer electronics (CE) specialty chain, has been acquired by a conglomerate for $4.5 million. The buyer, McMagic Partners, a subsidiary of Texas-based Khaledi Group, intends to operate the chain as a going concern under former Panasonic and LG Electronics regional sales executive Greg Regelbrugge, who will serve as CEO. According to the retailer’s Chapter 7 trustee Richard Samson, Vann’s assets were purchased “free and clear of liens and encumbrances” and McMagic has started “bringing the management team up to speed.” The sale successfully concluded on November 6, 2012.

McMagic, a holding company, plans to operate all five remaining Vann’s stores and expand to new markets. Vann’s filed for Chapter 11 bankruptcy protection in August 2012, several weeks after losing a major line of credit. The company said it had attempted several rounds of restructuring in an attempt to save the business, but financial support was deemed insufficient, forcing Vann’s to move into a structured liquidation. Vann’s moved from Chapter 11 reorganization to Chapter 7 liquidation in October 2012 to expedite the sale. The specialty chain was founded in 1961 by Pete Vann. The company helped pioneer authorized online CE sales in the late 1990s under former CEO George Manlove, and remains the largest independent CE retailer in Montana.

Abe’s of Maine Files for Chapter 11
Abe’s of Maine, the 33-year-old direct CE seller, has filed for Chapter 11 bankruptcy protection. According to a Nov. 5, 2012 bankruptcy court filing, the company sought Chapter 11 protection to reduce debt, improve liquidity, and find a backer to bolster its “long-term growth prospects and operating potential.”

Total fiscal year sales through June 30, 2012 were about $87 million, down from $110 million in 2011 and $115 million in 2010. President and founder Abraham Mosseri said he plans to sell or liquidate the business if an investor cannot be found. He currently employs 41 staff members.

Abe’s of Maine’s estimated assets are between $1 million and $10 million, including $2.5 million in inventory, and the company carries “substantial debt” of $11 million, the court filings show. Mosseri founded the privately held business in 1979 as a mom-and-pop photo dealer in Old Orchard Beach, ME. The company moved to Brooklyn, NY, in 1986, and in 2006 relocated again to a significantly larger facility in Edison, NJ, where it also maintains a storefront.

Abe’s of Maine had expanded its inventory to span the full gamut of consumer electronics, as well as pro audio, DJ equipment, and major appliances.

The company, which sells direct online, through third-party sites (e.g.,, via a catalog, and from its lone storefront, is ranked 56th in TWICE’s Top 100 CE Retailers report.

McIntosh Ships New Tabletop Speakers

McIntosh Laboratory has begun shipping its first AirPlay-equipped tabletop speaker, the $3,000 McAire. At that price, the single-chassis stereo speaker system joins a growing selection of very high-end single-chassis AirPlay speakers, including Bang & Olufsen’s recently unveiled $2,699 BeoPlay A9, a disc-shaped, floor-standing model that can also be wall mounted.

McIntosh calls the product an integrated audio system. It features McIntosh’s component-audio cosmetics with a black glass front panel with blue output meters. Its component size measures 8” × 17” × 19.4” and weighs 31 lb. Into that chassis, McAire packs a three-way speaker system and embedded Wi-Fi. The product doesn’t include a tuner or a CD player.

With embedded Wi-Fi 802.11 b/g and AirPlay, the speaker wirelessly streams music from Apple’s mobile devices and from a networked PC’s iTunes application over a home’s Wi-Fi network. The speaker also features an Apple-certified USB port with 1-A charging to charge and stream music from connected iPods and iPhones. The USB port also connects to USB mass storage devices, including Android devices, to play back music.
In addition, the port connects to iPads to play back its song selection, although the port isn’t Apple-certified for quick iPad charging.

The system features two 4” woofers, two 2” inverted-dome midranges, and two 0.75” dome tweeters. The power output was not disclosed.

Though McAire is McIntosh’s first AirPlay speaker, it is the company’s second AirPlay product. The company also markets the AirPlay-equipped MX121 home theater processor, which costs $6,000. McIntosh was recently purchased by Fine Sounds from D+M Group.

JBL Unveils Its Docking Speaker Systems

JBL unveiled some of the industry’s first docking speaker systems, the OnBeat Micro and the OnBeat Venue LT, with Apple’s new eight-pin Lightning connector for the iPhone 5, the fifth-generation iPod Touch, the seventh-generation iPod Nano, the iPad Mini, and the fourth-generation iPad. The OnBeat Micro features a pair of full-range drivers, a fully digital signal path with digital signal processing, AC/DC operation, USB port, and 3.5-mm auxiliary input (see Photo 2). The OnBeat Venue LT features a hidden Lightning dock connector behind the JBL logo, two full-range drivers and two tweeters, component video output, and Slipstream port to boost bass with low distortion. VC

January Products: HiWave Wireless Speaker, Power Amp Kit, Wolfson DAC

HiWave develops new wireless speaker platform

HiWave offers a Bluetooth wireless speaker demonstrator that runs for 100 hours at normal levels from a single charge cycle.

HiWave Technologies, a provider of innovative audio amplifier ICs, full-frequency range speaker drivers, and next-generation haptic-touch devices, has developed a new product called Endfire. Endfire is an efficient wireless stereo speaker reference platform that delivers 100 hours of high-quality audio playback at typical listening levels.

Endfire uses Bluetooth to pair with tablet PCs, smartphones, and laptops and outputs 30-W audio from its two full-frequency range, wide-dispersion HiBM36S12-8 BMR speakers. These are combined with HiWave’s DyadBA3 module, which supports both AVRCP and A2DP Bluetooth audio profiles and uses the HiAS2002 stereo amplifier. The system is powered by three 2,200-mAh Li-ion batteries and charged via a micro-USB connection.

The reference platform consumes less than 300 mW during typical playback and its onboard HiWave HiAS2002 (Audium) amplifier can switch voltage rails to reproduce peaks without any detectable artefacts. The system automatically enters standby when not in use and waking. Device pairing and battery check are controlled via Endfire’s volume control dial.

The HiAS2002 amplifier IC and BMR speaker drivers are available from HiWave. Visit for more information.


Akitika’s complete stereo power amplifier kit

Akitika’s GT-101 contains everything you need to build a stereo power amplifier.

Akitika’s GT-101 is a complete stereo power amplifier kit that supplies everything but the solder. It produces greater than 50-W RMS per channel into 8 Ω with low distortion and low noise. The kit includes a toroidal power transformer, film, COG capacitors, metal film resistors, heavy-duty extruded aluminum heatsinks, isolated input jacks, double sided FR-4 PC boards, five-way speaker binding posts, and a fully regulated power supply. It’s contained in a black custom chassis. The component quality is characteristic of high-end equipment, at a cost of a little more than $300. Akitika’s GT-101 stereo power amplifier sounds better because you build it. Visit for more information.

Caption: Akitika’s GT-101 contains everything you need to build a stereo power amplifier.


Wolfson’s newest DAC delivers great sound

Wolfson Microelectronics has introduced its latest stereo digital-to-analog converter (DAC), the WM8533, which provides audio performance in a small package for a wide range of consumer electronic applications.

The WM8533 delivers 106-dB signal-to-noise ratio (SNR) and features an integral charge pump, a software control interface, and offers 2 Vrms line driver outputs where a 3.3-V power supply rail is used. The WM8533 is suitable for a wide range of consumer digital audio applications including set top boxes, digital televisions, DVD players, and games consoles.

The WM8533 also features ground-referenced outputs and a DC servo to eliminate the need for line driving coupling capacitors and effectively eliminate pops and clicks at power on. The device also supports all common audio sampling rates between 8 and 192 kHz. For more information, visit

New Year, New Goals

With the January issue we mark the start of a new year. Our main aim is to discover and publish insightful articles about innovative DIY audio projects, handy design tips, essential acoustic theory, top industry events, and audio product news and reviews. In addition, we have goals for 2013 relating to the magazine’s layout and its website. Take some time to think about what we’re planning and feel free to let us know what you think. This is your magazine.

In his audioXpress January 2013 article, Doug Ford describes the design of a passive-matrix surround-sound decoder. The decoder features an analog time-delay that he implemented with a large number of cascaded all-pass networks. (Source: D. Ford, AXJan13)

In the near future, we’ll unveil a redesigned, modern layout you’re sure to find interesting, aesthetically pleasing, and useful all at once. Don’t worry. We’re spending ample time considering everything from fonts and colors to table styles and equation presentation. To address the needs of 21st-century readers, we’re asking relevant questions such as: How should we present  different forms? Can we incorporate additional graphics and images (e.g., infographics) to enhance the readers’ experiences with each issue? Can we use the magazine’s layout to engage more readers directly and foster more discussion and idea sharing in the audio community? The answers will influence the final product.

As for the website, we’ll build on 2012’s upgrades: we consolidated the content sections (e.g., audioXpress and Voice Coil) into one site; we chose an effective, easy-to-read blog-style  format; and we made membership management more user-friendly. From here, we’ll bring you more content on a more frequent basis. For example, we plan to deliver hi-fi product news in real time. We’ll also enable more authors to post articles on the site.

We hope you’re as excited as we are about these upcoming changes. For now, though, enjoy the January issue.