Tuesday, November 30, 2010

Mainland Chinese Rare Earth Monopoly: Bad for the Hi-Fi Industry?

Even though Beijing had resumed rare earth metal export to Japan, does the Mainland Chinese monopoly on rare earth metals bad for the hi-fi industry in the long run?

By: Ringo Bones

When it comes to the use of rare earth based ultra powerful permanent magnets, the hi-fi industry is probably without equal. From the relatively large samarium cobalt and neodymium boron iron magnets used in dynamic loudspeakers to the tiny magnets used in tape-based analog tape record / playback heads known for their glorious non-fatiguing warm analog sound. Not to mention the CD / DVD player and LP turntable motors that contain rare earth magnets, come to think of it, the hi-fi industry is probably the most rare earth dependent consumer electronic industry on the face of the planet.

Even though Mainland China’s quotas of rare earth metals being exported into the global market has more or less returned to the pre-conflict with Japan levels back November 24, 2010, Mainland China’s virtual monopoly of the global rare earth metal industry is not only detrimental to the world’s high-tech industry that’s very much dependent on rare earth metals but also its concept of “quality” – especially when it comes to hi-fidelity audio – is wholly different that of the Japanese obsession with Single Ended Triode amplifiers or of the Western concept of absolute sound quality in general. I mean had Mainland China ever produced its own version of a cost-no-object CD player set to rival the sound quality of a 7,000-euro German made Burmester CD player?

With Mainland China’s proposed 120 nuclear reactors it plans to operate to lower the country’s carbon footprint, rare earth metal export quotas might further be reduced. After all, they would probably be using their mined dysprosium and holmium as burnable poisons for their fission-type nuclear power plants. Not to mention the use of other rare earth metals for the magnetic relays, making the hi-fi industry yet again raise prices due to rare earth metal scarcity and pass on the expense to us hi-fi enthusiasts / capitalist consumers.

Add to the recent Wikileaks revelation that the Beijing government wants a North and South Korean reunification with the Seoul government in charge wold pose a rather significant geopolitical risk in the security of Mainland China's ability to maintain the commercial trading of rare earth metals. It would be sooner rather than later that Mainland China’s virtual monopoly on the rare earth metal industry won’t allow it anymore to keep up with global rare earth metal demand since all the rare earth metals it produces will only be enough for domestic consumption.

Thursday, September 16, 2010

Can Recorded Grunge Guitars Destroy Your Tweeters?

Once often asked during the rise of Seattle Grunge movement, do playing recorded “grunge” guitars on your hi-fi kit eventually destroy your tweeters?

By: Ringo Bones

Part of the rationale of owning a really good hi-fi rig is the ability to play loud without hurting your ears with aggro of distortion. Surprisingly, I’ve just recently found out as recently as a couple of weeks ago that there are still really – I mean really – naïve audiophiles who genuinely believe that playing recordings of “grunge guitars” – i.e. highly distorted and very loud electric guitar passages can eventually result in tweeter damage of your loudspeaker. I don’t know if these naïve audiophiles ever actually heard one played live or been in a Nirvana or a Soundgarden concert, so it is yet premature to judge. But the “assumption” that such “hot guitar tone” can fry tweeters is partly based on misinformation over amplifier clipping.

Every audiophile and hi-fi rig owner knows that pushing a power amplifier into hard clipping – i.e. playing it too loud that it no longer sounds nice – will “fry” or burn out your loudspeakers’ tweeter coil because the clipped waveforms contain much more high-frequency energy than a typical music signal. Given this truism in the physics behind the workings of electronic amplifiers, one will thus be curious enough to ask: “What happens when the music itself naturally contains heavily distorted clipped sounds – like those in loudly played and distorted electric guitars played through a fuzz pedal set on high or even extremely high? Will this result in tweeter damage too?

The truth – fortunately to us rockers – is that distortion produced by electric guitars played through “fuzz” or distortion pedals being set to extreme grunge is not nearly as destructive in comparison to actual amplifier clipping. Sound quality wise, I really don’t believe that the distortion tone created by guitarists and their special equipment is nearly as rich in harmonics as the distortion produced when a power amplifier truly clips.

The upper frequency of the harmonics produced by an overdriven guitar amp is limited by the instrument amp – which is more likely vacuum tube equipped with an output transformer coupled into a single-coned electric guitar loudspeaker – and the medium in which the instrument is recorded on – i.e. analog magnetic tape running at 30 inches per second. Ultimately restricting the bandwidth of a loudly played distorted electric guitar to lows of about 75-Hz to highs of about 5,000-Hz.

Just listening to such Seattle Grunge music makes me feel that much of the distortion behind its distinctive tone occurs at midrange frequencies where our ears are most sensitive to, rising into the treble range but decreasing in amplitude as the frequencies of the harmonics rise. A typical “clean” jazz guitar track played on a vacuum tube-equipped combo guitar amp typically measures 200 to 300 % total harmonic distortion. The electric guitars in a typical Seattle Grunge rock’s total harmonic distortion figure probably lies closer to 1,000% THD or even more.

Furthermore, if tweeters were actually being destroyed during playback of such music, older audiophiles would have read about it in 1990s era hi-fi magazines. And might even necessitate labelling such cassettes and CDs back then with warnings of potential tweeter damage when played loud in addition to the PMRC Parental Advisory, Explicit Lyrics warning stickers. Fortunately for music lovers of the world, no tweeters had even been martyred alongside Kurt Cobain during the heyday of Seattle Grunge.

Audiophilia Nervosa: Ear Pornography’s Inevitable Consequence?

The “audiophile disease” that first gained widespread notice during the mid 1990s, is audiophilia nervosa the inevitable consequence of compulsive hi-fi tweaking?

By: Ringo Bones

This insidious “audiophile disease” can easily infect an unwary audiophile noticing how a DIY RG-58 cable being used as an ad-hoc interconnect managed to sound way much better – sound quality wise - than the “scrawny” freebie interconnect that came with the newly-purchased CD / DVD player. And before you know it – especially if you’re not careful – audiophilia nervosa is often that not far behind, but should it be?

From my perspective, it usually afflicts audiophiles with a fairly narrow musical taste – genre wise. Or those intentionally unwilling to explore other genres of music are highly susceptible. Depending upon one’s perspective, a music reproduction system – namely the hi-fi rig that you own – should not influence which music you play on it. But more often than not, many hi-fi systems do.

Now is the time to ask yourself, does your hi-fi system make you exited about the music you play – or the way it sounds? If it is the latter, it’s no doubt you have now an advanced case of audiophilia nervosa and should take steps – really careful steps – to avoid forgetting your record collection. In a perfect world, your hi-fi rig should steer you – the listener – away from itself by letting the style and content of music carry you away. But more often than not, one is more likely distracted by overkill bass and supermarket tabloid style attention-grabbing treble. Well, at least my current hi-fi rig can play a well recorded rock drum kit way better than the hi-fi currently being stocked at our local mall. Or was it making the recorded singers sound like their right in front of me?

Sunday, August 22, 2010

Digital Loudspeakers: Viable Hi-Fi Technology?

Given that almost all aspects of domestic hi-fi front-end has already gone digital these days – digital radio broadcasts, CDs, DVDs, digital music downloads, etc. Are our hi-fi loudspeakers the next component to go digital?

By: Ringo Bones

Virtually all aspects of hi-fi that’s still commercially viably traded has already gone digital, thanks to the slogan Going Digital and Digital Ready being brandished about for much of the 1990s. As in digital radio broadcasts, digital music downloads, CDs, DVDs, digital preamplifiers, digital power amplifiers, etc. Even analog TV broadcasts in the US has since virtually gone digital back in the middle of 2009. But has anyone recently checked if the humble hi-fi workhorse, namely the ubiquitous hi-fi loudspeaker, has already gone digital?

Back in September 1998, a start-up digital speaker development company called “1…Limited” has then announced a new drive to attract investors and partners (I smell IPO?). The Cambridge-based company at the time aimed to make its innovative technology out of the laboratory and into production – and hopefully into your listening room – within two years. The design concept of 1…Limited was a panel matrix loudspeaker which runs from raw digital code (SPDIF?) without the need for any Digital to Analog Converter (DAC) or power amplifier. Given that our ears – as far as we know at present – are analog and, therefore, a digital speaker must create sound waves in the air by integrating air pressure pulses – from an amplified bitstream from either CD or DVD player into the listening room.

During the past 30 years or so, all major consumer electronic manufacturing firms – Philips, Sony, Panasonic, etc. – have been working on digital speakers, more often than not filing their very own patents to the nearest patent office of their very own versions of the same theme – i.e. digital loudspeakers. And all of them eventually found out first-hand the nasty surprise that’s in store.

Full working details of a digital loudspeaker were already published back in April 1980 – three years before CD was commercially launched by Sony and Philips. The article appeared in the now defunct magazine called Hi-Fi For Pleasure. The author was Stan Curtis – who eventually invented the audiophile CD player in 1985, later became MD of Wharfedale loudspeakers and Chairman of IAG, which owns the hi-fi company Quad. Stan Curtis’ article was spread over two pages and included a block circuit diagram and sketches said to be taken from a patent application filed by a Japanese company.

The system was called DARTS, or Digital Action Reaction Transmission Speaker, and it has been developed by NEBCO, the Osaka-based Nippon Electrical Bearing Company. Before reporting on the demonstration to selected journalists, Curtis reminded everyone that the loudspeaker has been the major stumbling-block to any progress in the digital chain – i.e. a truly all-digital hi-fi system.

NEBCO set up a demonstration using specially produced digital discs replayed on a prototype Sony disc player. According to Stan Curtis, the subjective performance defies description. There was no noise, no distortion, no coloration, wow and flutter or rumble, and apparently unlimited reserves of volume. The result could not be compared to anything heard previously: it was just so real. One particular revealing passage was an atmospheric-sounding street recording. Being reproduced at sensible level, the effect was as though someone had opened a window out on to the street.

NEBCO’s sketches showed a flat panel built from a helix of numerous tiny pistons, selectively triggered by a digital bitstream. For low-level sound, only the central drivers were switched on, to pump a few packet pulses of air. As the pitch and volume or a note rose, more drivers were rapidly triggered. At maximum sound level, all the drivers pumped. The discrete packets of air integrated in the room to create an analogue soundwave. Because each driver was either on or off, there could be no distortion or coloration like that found in a conventional analog speaker.

NEBCO promised a 450-quid bookshelf version, but it never appeared. Those in the know where not surprised because Stan Curtis wrote the article under the pseudonym Olaf Pirol – an anagram of April Fool. For all intents and purposes, DARTS was an elaborate hoax to celebrate the first of April 1980 a.k.a.April Fools Day. When 1998 rolled in, only a few hi-fi industry insiders knew the truth. But Stan Curtis eventually owned up to the elaborate hoax that he created through a trade magazine called Inside Hi-Fi in 1998. A few years later, he still finds hi-fi designers who wonder whatever happened to DARTS.

Unfortunately, most existing patent laws around the world makes no distinction between fact and fiction, a mere blueprint from an actual functioning and working prototype. In short, you can definitely patent a blueprint even if the device portrayed by it doesn’t work in real life. Although Olaf Pirol’s digital speaker article was fiction, it will still block anyone who now tries to patent a similar idea as fact – even if he or she possesses a working prototype.

Tuesday, August 10, 2010

Ear Pornography: Do Audiophiles Know it When They Hear It?

May have started as a Quixotic quest to make our hi-fi rig sound like live music, but does tweaking our hi-fi rigs to make them sound better than the real thing nothing more than ear pornography?

By: Ringo Bones

The concept may have started when some audiophiles and hi-fi enthusiasts who can’t take some of the dark and brooding aspects of Vladimir Horowitz’s piano playing resorted to tweaking to make the famed piano player sound like the bright and breezy Liberace. From then on, audiophiles have used judicious choice of analog and digital interconnects and speaker cables and tube / valve substitution and Rubycon Black Gate capacitors – with varying success – to make their favorite artists sound like the way their respective egos intend them to sound on their hi-fi rig. But is it still keeping up with the spirit of owning a hi-fi in the first place – that is the life-like reproduction of music in the home? I mean is the concept of ear pornography nothing more than the really Quixotic quest to make your hi-fi’s sound reproduction abilities better than the real thing / real life?

The hi-fi inconvenient truth is that we don’t actually listen with our ears, we actually listen with our minds and our emotions (or egos?). In short, how much we hear depends very much on how much we want to hear. Subconsciously, our mind can block out everything but the music or scrutinize the most subtle nuances of the musician’s rendition of a certain piece of music or the recording engineer’s production techniques. Every hi-fi enthusiast has a preference somewhere between these two extremes of auditory scrutiny.

To the uninitiated, the clean and clinical sound of contemporary digital-based hi-fi can be a pain in the ear to anyone weaned on the mellow and mellifluous sound of yesteryear. Choosing the right interconnect cables to make the audiophile recordings - if they have one - of your favorite artist. Like Taylor Swift, Nina Gordon and Louise Post of Veruca Salt, Anneke van Giersbergen of the Gathering or Liz Phair sound like a Central Asian Bardic Diva may seem like mere ear pornography to the unsympathetic audiophile. Strange, given that people who are generally offended by conventional pornography are more often than not suffers from poor body image. Does this mean that people who are offended by ear pornography are either tone deaf or is not blessed with a decent singing ability? Still, there’s a good chance that worthy audiophiles will probably know ear pornography when they hear it.

Thursday, June 10, 2010

Can Tweaking Your AC Cables Actually Make a Difference?

Electrical engineering-based logic dictates that doing such tweaks shouldn’t make a difference, but does tweaking your AC cables by using higher quality cables improve your hi-fi system’s sound?

By: Ringo Bones

As with the crappy quality freebie analog interconnect cables that most seasoned hi-fi buyers are already familiar with, an overwhelming majority - if not all – freebie IEC AC cords that come free with newly-purchased hi-fi equipment is stifling their ability to display their full sound quality potential. More apparently so when entry-level audiophile AC cords are substituted to the free AC cords that came with your CD player or other hi-fi audio equipment. Inexplicably, major electronics manufacturers seem to be unable to move away from supplying crappy analog interconnect cables and IEC AC power cords with their products.

From an electrical engineering perspective, one can logically deduce that tweaking the last ten feet of your AC mains cables by using higher-spec copper wiring configured in proprietary geometric configuration that results in RFI and EMI noise cancellation shouldn’t make a difference, doesn’t it? I mean the AC power that traveled from the generating plant all the way to your home is not exactly made with copper of 99.9999% - i.e. of six-nines purity. Neither are they ceramic-coated with superconducting “space age” materials nor have Teflon dielectric, and chances are doesn’t have conductors arranged around some mystical geometric pattern. Existing electrical codes around the world specify that 99.9% copper is good enough. Then why does using fully tricked-out AC cables – even those IEC AC equipment entry-level ones priced at around 20 to 25 US dollars – during the last 10 feet of mains to your CD / DVD player and power amp make such a noticeable improvement in sound quality?

I’ve heard the theories before – most are dismissed by “mainstream” / “tenured” electrical and electronic engineers as mere voodoo, but more importantly, I’ve heard the difference. As in greater dynamic range as if the music being played seems to immerse from a blacker background then shining brighter than it did after the generic AC cords had been substituted with better ones. My converted audio-buddies who were mere civilian bystanders – in audiophile terms - when I first asked them to be listening guinea pigs back in the late 1990s had since swore that AC cable tweaking makes a more-than-noticeable difference. Even with a beer-budget version of the test that I have conducted when I replaced the AC mains cabling of my out-of-warranty power amplifiers with well-reviewed entry-level speaker cables.

Yes, even speaker cables of suitable thickness to handle the power demands of the integrated amplifier or power amplifier you intend to use them with had shown a marked improvement in sound quality. After asking a qualified electrician in our neighborhood if what I’m doing violates any existing electrical codes. He says – it is still usually a he even till this day – given that those speaker cables are rated up to 600 Volts AC or DC, it is quite ok to use them as mains cable. He says they may even be safer than existing “zip-cords” oft used as AC mains cabling since these speaker wires contain more copper – i.e. thicker diameter. They are only a few percentage points purer than the copper used in freebie AC cords – 99.9% of ordinary zip-cords versus 99.999% of the hi-fi speaker wire. Can that much purer copper result in an inexplicable increase in sound quality?

If you’re lucky enough to have an integrated amplifier or a power amplifier that still works / you are still using that has already past its warranty and you are confident of your DIY soldering skills. You can try replacing the captive AC cords of your preamplifier, power amp or even the CD / DVD or other front-end with entry-level speaker wire like those from Bandridge, Gale, or Cable Talk that are priced between 1 to 5 US dollars per meter to improve its sound quality. This tweaks works very well with entry-level solid-state integrated amps with old-style captive AC cords, making them sound much closer to budget tube amps made during the Golden Age of Stereo or those 3,000 US dollar French-made solid-state integrated amplifiers.

Another source of cheap AC mains cords that are way better than the freebies that came with your CD / DVD player or integrated amp’s Styrofoam packaging are those IEC AC cords designed to protect against Van Eck radiation phreaking. Remember Wim van Eck, that Dutch computer researcher who in 1985 published the on how electronic emissions from a computer can be eavesdropped? Well, a friend of mine from the US State Department gave me – as in for free - 30 sets of IEC AC cords that formerly used in their computers that are capable of Van Eck Radiation filtering back in 1998 after their office computer workstations were issued “improved” models. Those 30 sets of 1992 Van Eck Radiation-compliant IEC AC cords also improves sound quality of my equipment that takes IEC AC cords. About as good sound quality wise as models priced between 500 to 1,500 US dollars from Electra Glide, Yamamura and even Cardas.

That Crappy Freebie Analog Interconnect Syndrome

To the casual and first-time buyer it usually came with the Styrofoam that comes free with your CD player, but are those crappy freebie interconnects unduly ruining real hi-fi’s reputation?

By: Ringo Bones

Its only saving grace is that the plastic RCA plugs – or phono plugs as they are referred to in merry old England - are already gaudily color coded to whether it goes to the left or right channel RCA jack. But are these cheap freebie interconnects that comes with your CD player’s / cassette tape deck’s / turntable’s / tuner’s packing Styrofoam really have bad sound quality?

Flatteringly, they can make your real hi-fi CD player – or any other hi-fi front-end previously mentioned – sound just like a run-off-the-mill mini system boombox. Or in short, these freebie cables’ inherent crappiness can ruin the inherently excellent sound quality – in comparison to a run-of-the-mill mini boombox - of your “proper hi-fi” or “real hi-fi” CD player or any other “proper hi-fi” or “real hi-fi” front end. This phenomenon is probably the reason why some anti-hi-fi and anti-tweaking fanatics swear by to that all equipment sounds the same mantra.

During the latter half of the 1990s, I was fortunate enough to have the opportunity to employ a few of our local music fans as hi-fi “guinea pigs. Given that their only experience to high quality sound is the weekend recital of a pop music academy in our local mall and most – if not all - of their CD listening is via run-of-the-mill boomboxes could make them about the most unbiased hi-fi auditioning test subjects that anyone could find.

Using Veruca Salt’s Eight Arms to Hold You CD – which was newly released at the time – as an ad hoc “audiophile demonstration disc” all of them commented: “Yeah, it truly sounds that there are two girls singing just like in the Volcano Girls music video”. And “Those cables make the interplay between the Gibson Les Paul and Marshall Amplifier stacks and the drums sound as if it is happening real life.” Maybe the young lady meant “live”, but the most surprising thing to me is that they thought that CD could never sound this good. Comparing “proper hi-fi” interconnect cables – even entry-level price range ones with those crappy freebie interconnects that come free with the packing Styrofoam can be a “Road to Damascus”-like experience.

Despite of their excellent sound quality in comparison to crappy freebie interconnects, entry-level hi-fi interconnects are not exactly cheap. Ranging in price from 25 US dollars to 100 US dollars – they are easily more expensive that those ultra cheap Chinese Mainland made DVD players. You know ones that had been raved for their surprisingly good sound quality as a “30-dollar Wadia CD transport” and a “30-dollar Krell CD transport” (more on this in the future). Fortunately, me and my seasoned audio-buddies had found away to make “interim” hi-fi interconnects that are still way better sounding than those crappy freebie interconnects.

If you are handy with a soldering iron, you can easily make your own ad hoc audiophile interconnects by using 1 or 2-meter sections of RG-58 or RG-59 cables and soldering them to reasonably-priced RCA plugs – or phono plugs for those living in the UK. If you know the right people, you can even get used RG-58 and RG-59 cables at 5-meter sections for free, while entry-level gold-plated RCA plugs – reliable ones - hover around 1.50 US dollars each. With a capacitance rating hovering around 28 to 32 picofarads (or pF) per foot, they can even be experimented as an ad hoc digital interconnects which I’ll discuss in a latter topic.

Sound quality wise, RG-58 and RG-59-based DIY analog interconnects have a more natural portrayal of the Gibson Les Paul and Marshall Amplifier sound as played in the opening of that Veruca Salt song titled Loneliness is Worse when compared to those crappy freebie analog interconnects. I have an audio-buddy who is “very careful with money” is still using the RG-58-based DIY analog interconnect cables I made for him back in 1998.

But why do reputable hi-fi CD / front-end equipment manufacturers still provide crappy freebie analog interconnects? God only knows, but this syndrome is not just confined to the entry-level price strata (the very competitive100 to 500 US dollar price range) of CD players. One of my audio-buddy fortunate enough to afford Sony’s 3,000 US dollar CDP-XA7ES CD player back in 1995 was somewhat astonished to find out that this 3,000 US dollar CD player too was afflicted with the crappy freebie analog interconnect syndrome.

Though his prized possession still runs till this day although he was a bit peeved when the rest of his audio-buddies has stumbled upon the phenomena of the 30-dollar Wadia CD transport / 30-dollar Krell CD transport last year – i.e. 2009. More so when it made our trusty-but-rusty 500-dollar Audio Alchemy DAC circa 1995 sound “superficially” way better than his 3,000-dollar Sony CD player bought in 1995.

Motional Feedback: The Future of Loudspeaker Design?

Best known as the working principle behind Velodyne’s patented High-Gain Servo System-equipped subwoofers, is motional feedback truly the future when it comes to hi-fi dynamic loudspeaker design?

By: Ringo Bones

Seasoned audiophiles, more often than not, had their first hand encounters with motional feedback technology via adverts – and hopefully purchases – of Velodyne’s world-famous servo-controlled subwoofers. These famed subwoofers are famed for their very low levels of harmonic distortion and coloration – when compared to their competitors’ offerings – that doesn’t use Velodyne-style High-Gain Servo System technology. But before we proceed any further, here’s a primer on what is motional feedback.

Motional feedback uses a second voice coil on the drive unit – typically a large woofer in stand-alone subwoofer systems – that provides a signal in which a tiny millionths of a second later is fed back into the amplifier, correcting distortion. The result – if correctly implemented – is amazingly powerful articulate bass / low frequencies devoid of coloration and distortion.

In those famous Velodyne subwoofer adverts of the 1990s, the company points to their use of a low mass – 2.5-gram accelerometer – that form the brains of their High-Gain Servo System. Velodyne mounts this amazing device directly on the voice coils of their subwoofer drivers, and measures the actual movement of the driver. The information is then sent back to a circuit, which makes corrections for any deviations from the pure output signal 3,500 times a second. Resulting in a virtually distortion-free bass even when the subwoofer is set at its highest frequency setting of 120-Hz.

My encounter with Velodyne’s FSR-18 subwoofer – one of the very best subs that we (me and my audio-buddies) can still afford when we still have Clinton administration era prosperity money during the 1990s. It can easily be described as a technological tour-de-force, imagine very loud and very clear bass subtle enough to portray the acoustic structure of the venue where the music being reproduced was originally recorded. Although early samples of the Velodyne FSR-18 subs were notorious for having loose wiring that came loose and slapped against the moving cone producing a tapping sound – evident when What’s Left by Lunachicks – from their Pretty Ugly album - was played during that particular listening session. Thus resulting in another flight to Hong Kong to our very friendly hi-fi dealer that gladly replaced our faulty subs.

In reality, motional feedback-type loudspeakers are a pain to design and make to work properly – tweaking one should only be a job for very gifted electrical / electronic / mechanical engineers – i.e. probably those skilled enough to make a humanoid robot that can run a hundred-meter dash in less than 10 seconds. It is not just Velodyne who had faced such problems developing and perfecting their very own motional feedback-equipped loudspeakers. Celestion and once-upon-a-time-loudspeaker-manufacturer Philips also experienced first-hand challenges one will likely encounter when flirting with motional feedback technology.

Graham Bank of Celestion once stated in a hi-fi magazine interview that a lack of positional reference in their prototype motional feedback loudspeaker design resulted in an enormous crack from the cone as it attempted to leave the chassis on musical peaks. Each time it did this, the connecting braids carrying the signal from frame to the voice coil broke, even though they were long enough to cope with the movement. Both Graham Bank at Celestion and Paul Mills at Tannoy have worked on motional feedback-type hi-fi loudspeakers during much of the 1970s and were somewhat convinced that that there were some deep seated difficulties in its application.

Even a notable demonstration of motional feedback technology by Philips – back when they were still making hi-fi loudspeakers – at their headquarters in Eindhoven, Holland, that motional feedback gave the sort of fast, tight and even bass most hi-fi enthusiasts dream about. Fantastic bass quality - provided that the user kept the volume down, otherwise, the driver instantly destroyed itself. The technicians at Philips also noted in their motional feedback loudspeaker experiments conducted during the 1970s is that much of the correction by the accelerometer and the servo system was being applied to signals above 100-Hz.

So is motional feedback the future of high-end hi-fi loudspeaker design? Well, remember how Velodyne’s FSR-18 subwoofer compares the deviation from the pure output signals and the one sensed by its low-mass accelerometer at 3,500 times per second? This is just with an audio bandwidth that rolls-off at 120-Hz – although it works beautifully, imagine this concept applied to the full Redbook spec CD audio bandwidth of 20,000-Hz. Corrections would be applied at 600,000 times a second – that’s just with a 20,000-Hz bandwidth. Imagine the difficulty with DVD-audio or Super Audio CD / SACD that reaches out to 100,000-Hz – a motional feedback hi-fi loudspeaker with a 100-KHz bandwidth would be doing servo corrections at 30-million times per second. Full audio bandwidth motional feedback hi-fi loudspeakers may be the future if its quirks are ironed out, but for now – and for simplicity’s sake – they’re only practical for subwoofers that only play notes as high as 120-Hz.

Sunday, May 30, 2010

It Came From Outer Space?

Believe it or not, the Dolby noise-reduction system in the lowly cassette tape had their origins in radio astronomy work, where no hi-fi has gone before?

By: Ringo Bones

Most knowledgeable audiophiles – and probably even most radio astronomers – don’t know that Ray Dolby, of audio tape noise-reduction fame, did his early work in radio astronomy. This little noted and remembered factoid served as the basis for his inspiration in developing the Dolby-B type noise-reduction system. The very system that lifted the lowly cassette tape – developed by Philips as a lowly dictation recording medium – into the realm of convenient high fidelity audio home recording medium, thus earning Ray Dolby enormous wealth.

Ray Dolby’s early work in radio astronomy made him develop his electronic skills in developing ways to extract very weak cosmic signals from background radiation noise – and the increasingly “loud” Earth-based radio broadcast chatter. By the end of the Cold War, many radio astronomy communities had asked Dolby Labs – as a philanthropic gesture – to honor its founder’s origins and further Ray Dolby’s earlier work by applying some of their know-how toward reducing RF noise here on Earth. Particularly at frequencies of interest to radio astronomers.

By the end of 2009, something strange happened. Frank Drake – father of the Drake Equation often used to compute for the probability of intelligent life elsewhere in the Universe other than our own – had surmised that given the current trend to fiber-optic bound Internet telecommunications, our planet will soon be invisible to radio telescopes elsewhere in the Universe. Looks like those old Star Trek original series broadcast will soon be the last RF signals that we’ll be “accidentally” sending to space once Internet TV comes on line and gains worldwide acceptance. Looks like Ray Dolby’s noise-reduction system and analog TV signals streaming out into interstellar space will inevitably be consigned to the dustbin of history.

Tuesday, March 30, 2010

Surround Sound From Just Two Speakers?

The concept gained popularity during the 1990s as three-dimensional stereo or surround sound from two loudspeakers, but is it possible to have surround sound with just your front left and right speakers?

By: Ringo Bones

Older audiophiles would probably credit the 1957 EMI release called the SDDI stereo demonstration LP with its traffic noises, trains and an orchestra as the first two-channel surround sound capable recording. Yes, it has only left and right channels, but this EMI test LP record can project a soundfield behind you without the aid of rear speakers. By the late 1960s, probably by creative accident, Jimi Hendrix made his guitar fly around and behind the listeners head – something two-channel stereo supposedly can’t do – via creative flanging in the song Bold as Love from the album Axis Bold as Love. Unfortunately, no audio engineer during this time has reliably able to do the same with natural / field recordings – i.e. the sound of a bee buzzing in front then behind your head as it sounds in real life – using standard two-channel stereo.

Hence the hi-fi and record industry in the very tail end of the 1960s decided that since the multitudes already have stereo, maybe we’d introduce them to surround sound. And when 1970 came, everyone witnessed the birth of quadraphonic sound – it was called as such because educated people knew Latin in those days. Unfortunately, a format war resulted with many manufacturers introducing their own version of quadraphonic sound / four-channel surround-sound that the buying public became confused – and bought none. A surround-sound system based on a quad system patented by Peter Scheiber – i.e. Dolby Pro-Logic – which is very compatible to existing standard two-channel stereo was introduced too late, thus quadraphonic sound expired with barely a whimper in 1975.

Even though Dolby Pro-Logic eventually became the standard surround-sound format for home theatres of the 1980s, the prospect of getting surround-sound from just two front speakers is just too tempting a concept to ignore. A researcher from the Oxford Institute of Mathematics by the name of Michael Gerzon had been toying the idea at about the time when quadraphonic sound was on the wan that you don’t need four or more loudspeakers arranged around the listener for surround sound. Gerzon had uncovered during his research that it is possible to fool the brain into thinking that a sound lies behind you with just two front-placed speakers. That’s a lot of money and unnecessary boxes saved, thus various companies influenced by the data gathered in Michael Gerson’s research had released their version of two-channel surround-sound that are - fortunately for us audiophiles - compatible with each other. Thus came Thorn EMI Sensaura, OM 3D system and Roland’s RSS system – all three dimensional stereo surround-sound systems that works with just two channels at the beginning of the 1990s.

At around near the end of 1993, the Thorn EMI Sensaura two-channel compatible surround-sound system was announced to the unsuspecting audio world as a surround-sound system that uses your existing standard two-channel stereo. Developed by EMI in their Central Research labs by Dr. Alastair Sibbald and team, Sensaura is an ingenious and complex recording trick that relies on a comprehensive understanding of psychoacoustics to work properly. It processes acoustic positional cues into a recording, in order for the ear / brain system to hear sounds from all around the room. And the end result can work whether recorded on CD, LP or cassette tape – and Sensaura’s effects can only get better the better the recording format sounds. And it even enhances high-resolution digital audio formats like 24-bit 192-Khz sampled DVD-Audio.

Another system with an almost similar principle that had been first made commercially available to the public since 1991 is Perfect Pitch Music’s OM 3D system. Used in their Francinstein Stereo Enhancement System Plus, the OM 3D system uses psychoacoustic cues to position individual sonic images within a 360 degree arc anywhere about the listening position. The OM 3Dsystem has been successfully used on CDs, cassette tapes, and radio broadcasts, it has even been used by musicians and recording engineers to enhance musical styles as diverse as experimental jazz and children’s educational tapes.

Like Sensaura and Roland’s RSS system, OM 3D uses left-right channel time delays to make low frequency sounds appear to come from beyond the boundary of the loudspeakers. In fact low-frequency stereo 3D stereo is relatively easy to create. It is at high frequencies that the 3D system / two-channel surround-sound systems previously mentioned has to be really clever. Because our ear / brain system determines acoustic directions at high frequencies by analyzing the tonal spectrum of a sound as it enters the auditory canal.

Unfortunately, as all of these three-dimensional stereo systems became popular, competing discrete digital surround sound systems – like Dolby digital AC3 and DTS – were introduced during the mid 1990s. Though an overwhelming application of the two competing discrete digital-based surround-sound systems were for movie soundtracks, a majority of audio-store “cowboys” had the brilliant idea of demo-ing The Eagles’ Hell Freezes Over DTS surround encoded DVD to death. Thus making your 1990s era home theatre customer inextricably linking DTS surround-sound with The Eagles’ Hell Freezes Over DVDs.

Since 1990, the audiophile label Chesky had been featuring three-dimensional stereo demo tracks in their test CDs. Though it doesn’t say on the CD liner notes, but many “mainstream” CD recordings that had came my way since 1991 had demonstrated surround-sound capability in my standard two-channel stereo set-up. Like the studio version of Dead Skin Mask by Slayer from their Seasons in the Abyss album when the hapless victim of Ed Gein had been calling him from behind my back even though my stereo only has two front speakers. There are now probably a large number of CDs out there that has already been three-dimensionally encoded that only became apparent if your main front speakers are properly toed in.

The Diorama Effect in Stereo Imaging and Soundstaging

First observed as a visual artifact in 3-D cinematography, does the “diorama effect” also occurs in the world of audio?

By: Ringo Bones

Everyone might have very well underestimated the influence of James Cameron’s Avatar. Not only does it help sell a new generation of wide and flat 3-D capable video displays for the home, but also made everyone yet again notice what’s good and what needed improving about 3-D cinematography. Many 3-D cinematography enthusiasts point the blame at the “diorama effect” even though this visual artifact also occurs in prism-equipped binoculars, but does it have an audio equivalent that could give every hi-fi enthusiast a renewed bout with “audiophilia nervosa”?

Having been fortunate enough to acquire the funds to fully indulge myself in the experimenting and upgrading side of purist two-channel – i.e. stereo – audio during the past twenty-one years, a eureka moment finally dawned on me as I watched the 3-D version of Avatar. Especially the scenes of “near contemporary” military hardware and lush tropical fauna where every visual artifact that is incongruent with how our eyes see real life sticks out like a proverbial sore thumb. Which had me realize that two-channel stereo – like 3-D cinematography – has its very own version of the diorama effect that’s seldom discussed in the wider world of audiophile journalism.

Compared to how we hear an unamplified musical performance in nature, many purist two-channel stereo systems that I’ve encountered – especially those with transistor-based amplification – tend to produce a somewhat artificially structured soundstage. A soundstage that has a narrow listening area with imaging that locates recorded musical instruments and voices with a precision that never occurs in a natural unamplified musical performance. In short, an overwhelming number of two-channel stereo systems have the propensity to create an artificially detailed soundstage that sounds too good to pass muster as natural. The audio equivalent of the diorama effect?

Probably due to the way lithe budget integrated transistor amplifiers that became popular during the late 1980s tend to project acoustic images in a somewhat cubist manner, mainly due to the brightness their added switching distortion creates. Good sounding as these units are, audio enthusiasts who can afford experimented with tube based amplification – especially single-ended triode types – to minimize the cardboard cut-out like imaging producing the acoustic equivalent of the diorama effect of their audio system’s imaging and soundstaging capabilities.

Low power can be an issue, especially if you find the 300B single-ended triodes too dull and the even lower powered 2A3 has difficulty driving the speakers you currently have. But these designs are as good at individual precision images as any high-caliber transistor effort, though without that sharp-edge cut-out effect – i.e. the audio equivalent of that 3-D cinematography imaging artifact called the diorama effect. With good single-ended triode designs, you can as if walk around those individual sonic images. An audio refinement to make your stereo system’s imaging and soundstaging capabilities more akin to real life.

Thursday, February 25, 2010

The Listener: The Often Ignored Hi-Fi Component?

With a myriad number of tweaks already in under evaluation – and still growing, isn’t it strange that the most often ignored component in the hi-fi experiential chain is the listener?

By: Ringo Bones

Surely, this is yet another topic that won’t become a perennial bone of contention in the annual meeting of the Audio Engineering Society anytime soon. But do we – in the enthusiast’s side of the hi-fi community – find it just a bit strange that we, the listener, is the only major component in the hi-fi experiential listening chain that is not subjected to extensive tweaking. After all, our audio / stereo systems will not be listening to themselves anytime soon, right?

During the past few weeks, I’m beginning to wonder whether those “out-there” kind of tweaks – also referred to as advanced tweaks - are really nothing more than health and wellness tweaks, though not all of them, aimed specifically at us – the hi-fi listener / system owner. These “exotic” health and wellness tips are often referred to as alternative medicine by the Madison Avenue marketing men and they too are often dismissed by staunch objectivists as too “New Age”. Like those advanced tweaks that inextricably works to some degree in improving the sound quality of one’s audio gear. But what are they?

Drinking Polarized Water – a hi-fi tweak often attributed to Peter W. Belt. Polarized water in hi-fi tweak parlance is a drinkable water produced by placing a bottle or glass of water contained in a non-magnetic container to the north pole of a moderately-strong magnet - like loudspeaker and guitar pickup magnets - for 2 to 5 minutes. The listener drinks it in order to notice a marked improvement in sound quality of one’s audio gear. I think it works by relieving the stress of the listener. Allowing him or her to be musically more perceptive. As preliminary research by Professor Eshel Ben Jacob, a physicist from Tel Aviv University, have shown that stressfully purified water can make anyone who drinks it stressful. Maybe I’ll try drinking water purified by gamma radiation via cobalt-60, which is probably the most stressful water purification method that I know of – and has access to - in order to find out if this has a detrimental effect to the sound quality of my audio gear.

The Dreaded Pattern 5 Acupuncture Treatment – this is probably the most extensive and painful of all acupuncture treatments that’s offered to us – i.e. those of us without any lineage to mainland China’s great emperors whatsoever. But this particular acupuncture treatment has the greatest potential to restore the body’s energy and balance, although each one of the 47 or so needles that the acupuncturist had stuck into me felt like a 440-volt electric shock. The treatment did made me feel tired and sore, but after several minutes relaxing while listening to my audio rig, I’ve noticed that I’m hearing details that I never knew my systems lowly price tag had any right to produce.

A Vigorous Workout – it does work so well, especially after sever minutes when your body has assimilated all those endorphins produced during the exercise regimen. This not only makes you feel good, but it makes you feel as if you are listening to a much more expensive audio gear as you relax while listening to your favorite tunes. Better consult your doctor or GP first to find out if your body is up to it though.

A Several Days Fast From Your Audio Gear – this one is a perfect cure to those obsessive-compulsive tweakers. Try “vacationing” or “fasting” away from your audio gear for three days or more by hiking or fishing or doing any outdoor activity on your favorite spot as far from your audio gear as possible. You’ll be surprised how this one improves the sound of your audio gear and reduces your tendency to be an overly compulsive hi-fi tweak.

Of all these hi-fi / health and wellness tweaks that I tried, probably the most transcendent is the Pattern 5 Acupuncture treatment. It is transcendent in a way that it kind of makes you feel more contented of your possessions and the people around you. I wonder if the members of Grateful Dead have tried the Pattern 5 Acupuncture treatment? Anyway, all of them will not only improve the sound quality of your audio gear to some degree, but it also gives you – the listener – a much needed tweak to be better at all the other things that you do.