New Book Review and Historic Tape Baking Article Added

I plodded through Practical Audio Electronics by Kevin Robinson, hoping that it would be a good introduction to the subject. I made it through its 416 pages finding a lot of good reference material, but it just wasn’t organized in a way that made any sense to me, and therefore, to a reader who wanted to get a good understanding of signal flow, how circuit components interact, and how to go from concept to design or to learn what one needs to know to troubleshoot and repair an electronic audio device. You’ll find the review here should you want the gory details, but the short review is that I wouldn’t recommend this book other than as a shelf reference.

At the request of a long time AES colleague, I’ve posted what now should be considered a historic article about tape baking. Based on a paper published by Ampex, it describes the procedure, using common household materials, for (most of the time) restoring an unplayable tape with a surface that’s become sticky to playability. We know a lot more about the problem, why it occurs, and alternate ways of rescuing a pesky tape than we did back then and there’s a bit of incorrect information in this article based on what we thought then, but know better now. Check out the article here, and if you have a sticky tape to play, give it a try.

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NAMM 2020 Show Report Posted

A little this, a little that. Visit the Trade Show Reports page for this one and many others or click here to go directly to it.

Too much stuff, too little time. I need an intern.  😉

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2020 Winter NAMM Tidbits

Usually I try to get a few tidbits out before the end of the show and before the full report. This year the WiFi in my hotel was so slow that I couldn’t really get on to web sites to verify some facts and I didn’t want to rely too much on my feeble memory. Finally the clog cleared a bit so at least I can post these few notes.

NAMM is in full swing, and I’m behind on my daily blurbs as usual, so here’s a little catch-up. I’ll be writing about many of the things you read here when I get into my full show report, which should show up about a week after the show closes. As usual, I look at what interests me, and other than this mention of the existence of Bluetooth drumsticks, I don’t do drums.

My favorite from Preview day, and might be my favorite of the whole show – and it’s even a software product – is Perfect Groove from Rebeat Innovation. It’s a tool that imports a stereo master file and shows you how a vinyl cut will turn out. It’s not intended to replace the cutting (the reaI mastering) engineer, but rather to point out any potential problems in cutting to the digital mastering engineer so that he might make changes to the master to avoid those problems. In essence, it’s a virtual test cut without burning up a blank master.

Several years back, The in-ear earphone specialists, Sensaphonics, showed a system to resolve a problem with in-ear monitoring on stage, the fact that the mix was just too pure and gave the performers no sense of ambience that they get with monitor speakers. They added an ambience mic that could be added to the console mix to allow the players to hear what was going on around them. ASI introduced an updated version of this system. Working in partnership with Sensaphonics (who provides the earpieces), they’ve updated it with stereo ambience mics and a mixer that runs as a smart phone app, and done it at a considerable cost saving over the original Sensaphonic system.

Along the in-ear line, FIR Audio opened my eyes to a job that I never realized existed, but is certainly important, particularly for large touring and stage shows, that of, for lack of a better term, IEM Tech, They make a series of tools for the maintenance of in-ear earphones to keep them working up to par and troubleshooting when something goes wrong. Among there products are a vacuum cleaning system to suck accumulated ear wax out of the earpieces, a cable tester that accommodates all of the currently used connectors on both the earpiece and output ends, and an analyzer that generates an end-to-end frequency response plot of an in-ear phone. I can see this as being a valuable check-up tool to find problems before a performer does.

When I worked with Mackie in 1999-2000, I tried to get them into microphones. 20 years later they’ve introduced their first series of three microphones. The EleMent series consists of a handheld dynamic mic, a large capsule studio condenser mic, and a USB mic for the podcasting and content creation users. They’ve also broadened their CR series desktop monitor line which now includes, by woofer size, a 3”, 4”, 5”, and 8” two-way speakers with or without Bluetooth input, and a new 8” subwoofer.

PreSonus is celebrating their 25th anniversary this year (this is a celebratory anniversary year for several other companies, too) and announced a few new products. There’s a new rack-mount high I/O count interface in their Quantum series with Thunderbolt 3 connectivity. A new tabletop interface combines the features of the PreSonus FaderPort single-fader DAW controller with a 2-in-2-out USB interface. Also new to PreSonus is a new series of small format analog mixers. Not entirely analog, they serve as a multichannel USB-C or USB 2.0 computer audio interface and record stereo to an SD memory card. Also brand new is a small diaphragm condenser microphone that sells as a pair with a really sturdy stereo bar for $129.

Full report will be coming next week.

More coming in the full report.

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CES 2020 Musings

This isn’t like my regular trade show reports because CES isn’t like my regular trade shows. CES is a showcase for BIG things in the consumer world, not necessarily having anything to do with electronics – which is probably why they now call the show CES rather than the Consumer Electronics Show. Many of the things on display here are things you never thought you needed, interesting technical developments looking for an application, more things you can control with your smart speaker, and every once in a while, something that’s actually useful.

It seems that most press releases I received prior to the show, and they kept coming throughout the show and for a couple of days afterward, were for ear phones – hundreds of new manufacturers you’ve never heard of, with product almost ready for market as soon as they get the manufacturing kinks straightened out, get the software debugged, get the phone app written, etc. Nearly all claim to give you a listening experience like you’ve never experienced, mostly having to do with spatial signal processing. One of the more sensible features is the capability to fine tune frequency response and dynamic control to the listener’s ears. Another is to include a microphone that serves two or three purposes – making phone calls, provide active noise cancellation, and serving as a generic hearing aid for people who don’t want to admit they need one (or can’t afford one).

Sonarworks, for the past couple of years, has been selling headphone and room correction applications for the pro audio market. At this CES, they were introducing their new consumer audio product line under the brand name Soundworks, and featuring SOUND ID, “designed to disrupt the audio space and change how users will experience music, regardless of device.” While I’m suspicious of any technology described as “disruptive” – and that term showed often in product blurbs – I think Sonarworks does a pretty good job with their pro applications, so I wanted to give it a listen. Unfortunately, I didn’t get around to it, but they’ll be bringing it to the NAMM show so I’ll try to check it out there.

Dirac Research is a company that I know from AES shows. They make a very sophisticated and very expensive speaker/room correction system. Like Sonarworks, they’re dipping their toes into the consumer pool with a processing application HD Sound. It’s touted to enhance everything. In a quick listen, I thought the processed sound was worse than the unprocessed sound, but then I’m not accustomed to listening on earphones, nor am I accustomed to listening to the flavor of music that their system “enhanced.” I think this would be impressive to some listeners, but tiring to others.

Speaking of earphones, something that irks me about new technology is that it seems necessary to invent a new word related to the new technology when an understanding of the old word will do. One example is with disk drive interfaces. For many years, we had ATA (Advanced Technology Attachment) drives that had a parallel data interface – one wire for each bit of the data byte transferred between the disk drive and the computer. Then they invented a way to transfer the data serially, which was less expensive than the parallel way, and they called it SATA (Serial ATA). But then, just plain ATA wasn’t good enough, they had to rename it PATA (Parallel – which it always was – ATA). First we had wireless headphones that got their audio via Bluetooth transmission. Nobody noticed the wire running across the headband between the earpiece with the Bluetooth receiver and the one for the other ear. But when they started applying the technology to in-ear phones, they needed a place to put the Bluetooth receiver, so it went in a little block with a wire running to each earpiece. But, by golly, it wasn’t connected to the source with a wire, so it was wireless. Then they miniaturized the Bluetooth hardware and built in into the earpieces, eliminating the block and wire, and invented the “True Wireless” earphone.

And then there’s noise canceling earphones, where a microphone picks up ambient noise and a processed version is mixed with the audio feeding the ear pieces, essentially subtracting what the mic hears from what leaks in around the ear cushions. Then someone got a clever idea and put a tuned acoustical path from the outside to the inside that provided some cancellation of the ambient noise leakage with no electronics required. Or, the simpler version is just a tighter fit in the ear to block out (not really cancel) external noise.

But when the technology got to the consumer, the original design was given the new moniker “Active noise cancellation” to distinguish it from the non-electronic designs. This is what keeps marketing departments up all night. It’s a good thing that there’s a way to distinguish one from the other besides a battery compartment a switch – active noise cancellation done right always works better than passive implementations. Anyway, this is just a way to give nod to old friends Audio Technica, maker of fine earphones of all designs (and microphones and phono cartridges, too), who, at this show, introduced their first true wireless active noise canceling ear buds.

Podcasting is bigger than ever. Shure had a big isolation booth set up with a pair of microphones and some recording software, inviting people in to do interviews or just rant and rave solo while getting the feel of being a podcast journalist. I don’t think they were showing any new hardware here, just showing people how simple it is to set up and make a respectable sounding recording. Roland, who, in addition to the music and pro audio products that we’ve known for ages, has been in the pro video business for many years. At this show, they introduced a consumer level interface that integrates audio and video and delivers it in a format compatible with on-line streaming hosts. It uses two smart phones as camera, with some rudimentary video mixing, allowing switching from one to the other or split-screen, along with two mic input channels, which, if I remember correctly, can be either the mics on the phones or external mics. Like what Shure was showing, it’s a way to get some pro-appearing production on to the desktop.

Samson introduced a new mic for upscale podcast and broadcast applications. It has both a USB-C output with 24-bit resolution and sample rate up to 96 kHz for direct connection to a computer, and a standard XLR output for a standard mic preamp input. It’s a dynamic mic with a yoke, presenting the same kind of serious broadcast gear appearance as the E-V RE20, Shure SM7, and even Audio Technica and AEA have mics with the same general form factor, making the statement which I think is pretty much true, that if it looks like a broadcast mic, it will probably work pretty well in that application. One thing is that the way these mics are mounted (Samson also has a tabletop boom arm to go along with it) they just invite your best on-air performance. Whatever works.

Roland also showed a new keyboard controller that supports MIDI 2.0, though there wasn’t anyone around the booth when I dropped by who could tell me in what respects it supports the newly enhanced MIDI specification. One of the things that the MIDI folks are waiting to try out is the ability for each note can have its own performance characteristics. For one example, if you’re playing a guitar part on your keyboard, you can use key aftertouch to bend a string while the rest of the chord stays in tune. The new spec also supports higher resolution for MIDI continuous controllers, making them more continuous than before. I expect to get a full tour of the new keyboard at the NAMM show, where there are also a few technical sessions scheduled on MIDI 2.0.

Roland also had their Facet Grand Piano on display and demo. This is a concept model, not a production unit (yet) that has a very striking “floating” design, with transducers in the base that, applying Roland’s quite mature piano sound modeling, actually sounds very much like a piano. Its appearance made me think of the new electric Ford Mustang pickup truck.

I was expecting to seem more vinyl-related products, but I guess that’s so last-year. Audio Technica had a number of turntables on show, ranging from good quality consumer level with cartridge, RIAA equalized line level, or USB output up through a couple of contenders in the low end of the high end audio range. Allsop had their disk cleaner stuck off in a corner, something they’ve made, relatively unchanged, since the early LP days. I was expecting to see some more sophisticated disk cleaning systems, but nope. CES used to have a substantial high-end audio segment with $50,000 turntables and $30,000 monoblock tube amplifiers, but it was scaled back enough this year that I didn’t even bother to find my way to the handful of hotel suites. I think the proliferation of high end audio shows in the US and other countries have pretty much taken over what I used to have fun with at CES.

On the technology side with some potential audio applications were a couple of old-is-new-again things. Back in the 1980s, Phillips made a motional feedback loudspeaker that got some ears perked up, but it never really went further than a couple of models of desktop speakers that were eventually discontinued. The concept here is to incorporate the loudspeaker driver itself into the amplifier’s negative feedback loop with the idea being that non-linearity in both the amplifier’s electronics and the loudspeaker assembly can be reduced. The Phillips system used a driver with two voice coils, one to move the cone, the other to provide a signal to the feedback path that represents the physical motion of the cone. Two companies teamed up to bring back the concept using more modern technology. SubVo developed a transducer consisting of a flexible strip that attaches between the speaker’s voice coil and the frame, which bends with the cone’s motion, and this provides the feedback signal. Their partner, klara-T is developing DSP software that provides a correction signal that can be summed with the input signal and then amplified to loudspeaker level. At the moment it’s a design concept with the software running on a stock processor. Their goal is to be able to integrate their transducer with the speaker cone suspension and provide a chip to process the signal. Maybe they’ll get some traction this time around.

A little more down-to-earth reworking of the computer PCI expansion chassis is the Black Beast Pro from Lagarhus Products. It’s a box that connects to the computer via Thunderbolt and provides several bus expansion ports. It seems that the primary focus is on high power graphics cards, the sort of thing that people are using for putting together computers for Bitcoin mining as well as high end graphics used in 3D modeling and high resolution video. They’re pushing it as a way that you can add gobs of processing power to your laptop computer when you’re working on things that demand it, then unplug your computer and take it out in the field to do routine work.

Sometimes claims of technological breakthrough go just a bit over the top. Nanalog Audio Inc. claims to have “manufactured the first commercial molecular device.” Their technology is based on quantum tunneling, a phenomenon that appears to defy laws of physics that allows a sub-atomic particle to pass through a barrier. When dealing with quantum mechanics, though, this is apparently OK. Traditional diodes are made from silicon and germanium that allows current to pass through in one direction and not the other, with a section of their voltage-vs-current curve where small currents can pass in either direction. It’s how we make a limiter out of two back-to-back diodes. The nanotechnology that Nanalog has developed provides a way to make a carbon-based semiconductor chip with a much shorter “linear” region that, when used in audio small signal applications, provides a transfer curve similar to a triode vacuum tube. Their broad claim is that it can make everything sound better. Their first prototype product is a distortion pedal – actually three different pedals, each using a chip with a different length of “dead zone,” with each pedal offering a different character of distortion. Like any other guitar pedal, it’s a matter of taste. As a banjo player, to me it’s all distortion.

The press release I received from Navitas Semiconductor promised new chargers capable of faster charging and upwards of 100 watts of power available. The initial pitch was that it was all about “the transformer” as there was a bin of transformers on display. Pressing on further, I got the real scoop.

The old school chargers and wall warts are based on a linear power supply. The AC line voltage feeds a transformer that drops the line voltage down to a little higher than what the device to be powered or charged needs, the transformer output is rectified (to convert it to DC), then filtered, and maybe regulated, maybe not. Contemporary switching power supplies also use a transformer, but the trick that makes them more efficient, lighter, and ultimately less expensive to manufacture is where the transformer appears in the circuit. In a switching power supply, the full line voltage is rectified and fed to a “chopper” circuit to create a string of pulses with a high repetition rate, typically 100 kHz to 1 MHz. It’s this pulse string that feeds the transformer, whose output is then filtered and regulated to the desired voltage.

A 60 Hz transformer requires a lot of iron in its core in order to couple current from the primary to the secondary winding. A high frequency transformer requires far less core material. In addition, filtering 120 Hz full wave rectified AC from the power line requires large value capacitors, while a much smaller capacitor can filter the high frequency pulses. Aircraft instruments up until the “glass cockpit” days have all operated on 400 Hz power for the simple reason of saving weight.

So, basically what Navitas makes is a semiconductor chip set for a switching power supply designed for charging or powering home devices. Modern specifications for USB-C and Thunderbolt allow the device and power source to communicate so that the power supply knows the correct voltage and current to supply to whatever plugs in. The pitch is that with the proper cable and smarts on the device end, you can use the same power supply to charge your phone, your watch, or your laptop computer. They had several commercially available chargers on display that use their chips. It’s an interesting application, but it takes some clever arrangements to charge or power multiple devices at the same time. Even though the charger can deliver enough watts to go around, it needs a way to connect them, and connect them in a way so that each one gets what it needs.

Bluetooth is everywhere, 5G is advertised everywhere, VR is still looking for some good reason for being, so to wrap up, let me mention the Bluetooth golf ball from TuggaGolf. Lost your ball? You can track it on your smart phone with their ball and app. Given the limited range of Bluetooth, however, unless you hit your ball into a nearby deep rough, you probably can’t track it unless you walk around the course and get close enough to pick up its signal. But then, isn’t that what golf is all about?

I’ll be looking for some more practical stuff at the NAMM show later on this week,

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NAMM AES Academy Early Registration

Just a reminder that the last day to take advantage of the early registration discount is January 4. Sing Auld Lang Syne, have some egg nog, and register for the classes. See the post below for details.

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A3E At NAMM – Another Set of Panels and Workshops

A3E stands for Advanced Audio and Applications. Exchange. This is a group that’s dedicated to new audio and music technologies with a target audience of developers and programmers, musicians and audio professionals, and manufacturers of next generation music-oriented products. Like AES, they’re presenting a series of workshops and panels within the NAMM Anaheim complex (the Hilton) throughout the three days of the NAMM. These sessions are free for NAMM attendees, though they’re requesting that you register, which, at least at this time, means sending an e-mail. If you’re planning to attend NAMM, you should look over the program [Click here] for a full list of each day’s topics and presenters. Here are just a few from the long list that I find particularly interesting.

  • MIDI 2.0 – two different sessions
  • The Future of Music Synthesis – Physical Modeling and Expressive Instruments
  • Live Performance – The Future Concert Experience
  • Game Audio – Two sessions – Sound Design for Mobile Audio and Essential Game Audio Skills
  • Future of EDM Production
  • Future of Audio Development – a panel of neuroscientist talk about how it gets into your head!
  • The DDEX (Digital Data Exchange) standard – Metadata for your sessions and credits
  • Optimizing Your Audio Workstation’s Architecture for Maximum Creativity (presented by Intel)
  • Music Licensing and Micro-Licensing
  • Hot Rodding your DAW
  • Latest Windows Developments for Music Creation
  • Blockchain and Music Royalties

As with the AES advance registration promo code (see the AES Academy post), you can register for NAMM prior to January 6 for $50 using the discount code 2020A3EFUTURE


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AES Academy at the NAMM Show Final Schedule Is Now Available

It looks like a pretty strong program this year with a good selection of classes both hands-on and on technical subjects. In the past two years that AES has offered a program at the NAMM show, I haven’t been as enthusiastic as I should have been, mostly because the presentations were by gear manufacturers about how to use their gear – not at all a bad thing (and there’s some of that this years, too) but the scope of the program is a lot broader this year and you’re bound to find something interesting that’s worth the price of admission. One new perk they’ve added is that if you join the AES when registering for the Academy program (you can do it on site) you’ll get free admission to the classes. AES membership is $150 for a year or $75 for students.

Click here for basic information and the registration link

Click here for the full schedule of classes. Note that some have limited space so you’ll need to register in advance in order to reserve a spot. The Dante classes fill up fast.

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New Technical Article Series Added – Trust But Verify – Testing Your Gear To See If It Meets Specs

This series is the practical side of the series of articles on specifications. Learn about some tests you can perform on your own gear using (free) software and tools that you might already have or should have. It’s in the Technical Articles section. Three chapters (so far) each of which has its own PDF link. The topics covered are basic measurement concepts, frequency response, distortion, voltage and gain, frequency, phase, and latency.

Posted in Technnical Articles

PaleBlue Rechargeable AA Cell Reviewed

Why in the world would I be reviewing a battery when they’re so common? Well, one of the things that you get when you’re on the press list for CES is getting e-mail soliciting booth visits, more info, and an occasional review invite. Most of this stuff I just toss off because it has nothing to do with what I write about or use personally, but, hey, everybody uses batteries. When I got an offer for a review set, I bit. They work, they do what they’re intended to do, it’s a different and clever way to make a AA (they also make AAA) size cell, and it’s a bit quirky. You’ll find the review in the Clever Gadgets section of the Product Reviews page here. If you use them, use them wisely.

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Specifications – Removing the Mystery

I’ve added a bunch of articles about the meaning of specifications, how to make sense of a product’s spec sheet, what’s important, what’s not, and what you might not find that you might want to know. This is another series that I wrote for Recording Magazine, published on and off between 2014 and 2017. I haven’t completely re-written them, but made a few updates here and there. There’s an introduction and seven topics. You’ll find them if you scroll down to the bottom of the Technical Articles page where each article has its own link. As usual, they’re PDFs which I recommend downloading, and most of the illustrations are at high enough resolution so that you can read the fine print (like graph scales) if you zoom in.

I started a follow-up series called Trust But Verify that illustrates methods you can use to verify a device’s performance using tools that you probably already have, or can download or buy inexpensively. Only two of these were published before the magazine seemed to lose interest in the concept. I’ll be putting the three I’ve written on line here in the next few days after I proofread them.

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