January 2009

Audiolics Anonymous Chapter 111
Predilections
Article by Dr. Bill Gaw

  It is mid-November as I write this tome for publication in January. While this is a little earlier than I usually start, necessitated by the upcoming holidays, I hope to take some time off to enjoy my system. Why time off you may ask? Because making a job out of a hobby is the best way to kill any enjoyment obtained from it. You'd be surprised at the number of high-enders who've started reviewing, building or selling equipment who can't stand listening to music any more. Every year, at some point, I get into that mood and have to back off with the equipment evaluation and just listen for the joy of it. For a writer, the end of November to the end of December is a great time to re-energize my ears as the Holidays tend to interfere with the ability to do any significant writing anyway.

About six months ago, for some reason that I can't comprehend now, feeling that digital with the higher bit rate codecs now available had come close enough to analog to be "good enough", and with my phono-preamplifier giving me problems, my turntable and cartridge went on the used market. Happily for me, no-one bought it for the asked for exorbitant price. This was probably a Godsend, as, since then, analog has once again taken center stage of my listening.

While listening to vinyl, I've restarted my project of digitizing all of it, so that when I once again get fed up with having to get up off my fat ass every 25 minutes to change record sides, I'll be able to sit and enjoy recordings that probably will never appear on any form of digital, and that are significantly better musically than what's available today. No wonder Americans are getting corpulent with our remote controls keeping us glued to listening chairs. Our forefathers had to move their butts every three minutes or so with their 78's, and thus must have been more physically fit. Guess our future generations will suffer even more from muscle atrophy as storage media get larger and easier to use.

Over the past two winters, approximately 200 records have been transcribed using my Walker Proscenium Gold turntable with Kondo IO-J cartridge through the phonostage of a pair of monoblock VacuumState preamplifiers. This feeds a D/A converter running at 24-bit at 88 or 96 kHz to my hard drive for storage. Each record is cleaned on a Loricraft unit using Walker Audio Prelude Cleaning Solution, then destaticized with a Walker Audio Talisman. The finished product is then being stored on multiple hard drives on my modified home theater computer. They can either be played back through the computer using various software or turned into DVD-Audios using the Discwelder Bronze program by Minnetonka Audio. While the process takes about an hour per record, the finished product sounds almost as good as directly played back from the vinyl, lacking only the last bit of atmosphere that analog has over digital. With about 200 more records to go, I figure the project will take another year or two.

As I don't have any new equipment in for review at this point, and haven't done it in a while, I figured I'd waste both your and my time this month summarizing my audio predilections. So anybody out there with little to no interest in how I base my opinions, can go back to the Home Page and find something more entertaining to read.

These ideas have been discussed at length in previous columns, so a brief summary of each is given below.

1. Relative Importance of Things Audio
While audiophiles have argued over what is and is not important in audio, through years of trial and error and great expense, I've come to the following list of relative importance of all things audio from most to least;

a) Software: If the recording sucks, no system will make it into heavenly music. The corollary is that a great recording will shine through even on a cheap transistor radio.

b) Room: In the heyday of analog, there were always heated discussions of whether the source component was more important than the speakers, as these were the mechanical parts of the system that had the greatest amounts of distortion production. These days, with the massive improvements that have been made in the science of speaker building and the quality of even relatively inexpensive turntables and digital players, the problems associated with room acoustics have come to the fore. While in the distant past the only way to control room problems was to move around the loudspeakers to the least noxious room placement, this problem has been recognized by audio entrepreneurs and many solutions from mechanical absorbers and diffusers to digital signal processing equipment have been developed to control room resonances.

c) Electricity: This is becoming more and more of a problem, as both the electric company and your home appliances destroy the 60 Hz sine wave with noise. Even in the best systems with equipment with excellent power supply rejection of noise, some will get through. Again, electrical engineers have hopped on it and developed many different systems to clean up the AC, some of which are very effective and others that are a waste of money. Like any other piece of equipment, the effect is system dependant, and what works in yours may be worthless in another system.

d) Loudspeakers: Back in the early days of audio there were always debates going on as to whether the analog source or the speaker distortions were more important for sound quality. With Digital's relatively even playing field and the improvements in both vinyl and analog source components, loudspeakers are now next on the list. No matter how much you spend on one, even up to six figures, their distortions are significantly more than any other piece of audio equipment. Happily, there have been remarkable improvements in even inexpensive speakers over the past few years as the art of speaker building has been replaced by science, thanks to Floyd Toole and others. With the use of active crossovers, internal amplifiers built specifically for the drivers, new materials developed for cones, electrostatics and ribbons, and digital signal processing for both room and speaker correction, I foresee marked improvement is this weakest link of the reproduction chain.

e) Source Components: "Garbage in, Garbage out" still holds in audio. While there is no disagreement that analog equipment sound is very variable and quality dependant, there are still those who would argue that "digits are digits," and the least expensive CD player should match the best built or at least come very close if their analog sections are equal. Nothing could be further from the truth. Digital is just as variable in sound quality as analog depending on the number of digits recorded, how they are encoded and decoded, and how their conversion to analog is processed, the quality of the D/A converters, and the analog stages.

f) Pre and Power Amplifiers and Processors: As we proceed down the ladder of importance, quality differences of well-built pieces of equipment become less and less, and more difficult to differentiate and evaluate. There is much less difference in sound quality between a moderately priced and super expensive amp or preamp compared to the previous categories. Because the differences are small and require greater perception and emotional involvement, it's at this level that one needs to shift from short-term listening with rapid equipment changes in double blinded so-called ABX testing to long term relaxed listening sessions to get the feel of the strengths and weaknesses of components, and how they affect your perception of the music.

g) Interconnects and Loudspeaker Cables: This is probably the most contentious subject in high end audio. While some would say that any cable with low impedance, resistance, capacitance and inductance will sound like any other cable, there are others who claim that all cables sound different. Thus one group swears by zip cord and Radio Shack interconnects, while the other will spend more than what it would cost for a new car on a pair of speaker wires thicker than battery jumper cables.

The truth lies somewhere in the middle. While one with a fairly decent system and hearing should hear differences between cables, they are significantly less than other equipment, being more the coloring of the icing on the cake.

h) Tweaks: This is the most contentious area of high end audio, and the one most loaded with charlatans. It's also the largest, covering everything from equipment feet and weights, electrical contraptions to control EMF, AC and digital noise, to mechanical vibration reducers such as stands and shelves, to record and digital disc cleaners to allow better retrieval of signals. While many of these changes can be easily recognized for either the better or worse, others produce very subtle changes which require excellent perception and equipment and possibly many hours of listening to discern. In many cases, they are also very system dependent. "Caveat Emptor" certainly is the watchword here.

2. Music: Classical vs. Everything Else
While I enjoy Folk, especially that derived from the 1950's to the 1970's, bluegrass and some rock from the same era, the love of my life (hopefully my wife won't see this but she probably already knows) is Classical Music, primarily orchestral. One of my earliest remembrances is watching Charles Munch's last concert at Tanglewood with the BSO doing the Beethoven Ninth from the late 1950's. And while I watched the Bell Telephone Hour for its science at an early age, the biggest thrill of the hour was listening to the Ninth at the end of the show. Where this came from is anybody's guess, as my parents were into Frank Sinatra and Harry James, my mother played piano but only the standard 1940's hits, and the only record we had in the house was a 78rpm of Ghost Rider's In The Sky with Vaughan Monroe.

In sixth grade I started studying trumpet, as my father felt that I might be able to work my way through college playing in a dance band, but in seventh grade I switched to French Horn, an instrument that I had fallen in love with before turning ten. By the end of High school, I had played in several community orchestras, all county band and orchestra, and even did one concert in Symphony Hall with the Boston Youth Orchestra. Luckily, by then I had realized that my musical talents were not quite up to being able to earn my livelihood, and therefore settled on my second love, medicine. Unhappily, that meant giving up the horn, but happily, at least until a few years ago, the income was able to feed my voracious audiophile appetite for equipment and recordings.

3. Important Sound Qualities
There are six qualities to sound:

a) Pitch: Perception of sound frequency.

b) Loudness: Pressure of the sound wave.

c) Phase: Relative position of a sound wave in relation to other waves.

d) Direction: Where the sound is coming from in relation to the receiver.

e) Distance: Perception of distance to the source.

f) Timbre: Perception of the relationships of the sound's various frequencies or harmonics changing throughout time.

To the above, I would add a seventh

g) Ambiance: The perception of space surrounding the sound source.

Interestingly, many studies have shown that while all individuals with decent hearing can perceive all of the above, everyone is different as to how well they perceive them, everyone places a different emphasis on each, and one can be trained to either increase or decrease our perception of each. For instance, in my case, not having perfect pitch perception, while I can tell when one instrument is off pitch compared to another, especially when they beat against one another, it doesn't bother me appreciably when a recording is a little off pitch, and I have attuned myself to not listen for wow and flutter with analog recordings.

Timbre is of somewhat importance, but again, after listening to many systems over the years, I have trained myself to be able to listen through modest variations after recognizing the variation.

On the other hand, when evaluating a system or piece of equipment, perception of Distance and Direction are of importance as they tell me whether the  channels are properly balanced and able to output exactly the same sounds. For instance, as no two speakers have exactly the same output or are perfectly flat across the frequency spectrum, there will always be discrepancies in instrument placement in the sound field as notes of different frequencies are played. The more perfectly the left and right channels produce the volume and frequencies of the different notes and their overtones, the more stable the stereo image will be.

Loudness, the ability to produce pppp or ffff and all of the pressure levels in between, is also important to me, especially, believe it or not, the softer end of the scale. While a true forte fortissimo of an orchestra is thrilling, a true pppp can be spine-tingling, and is actually more difficult for a system to reproduce.

There are actually two types of Phase in recordings, relative and absolute. Relative, having two or more channels in the same phase, is very easy to perceive, as perfect relative phase will produce a stable pin-point image, while one channel out of phase with another produces a diffuse "all over the place" field. Absolute phase is reproducing a sound in the same phase as the original, in other words having an increase in sound pressure not be reversed as a decrease. Unhappily there is no recording standard for this and thus different recordings tend to be evenly balanced as to whether they are in one or the other absolute phase. If you are not sensitive to this, don't learn it as you will go crazy every time it switches from one recording or even sometimes from one track to another. On the other hand, being able to perceive and correct for it will give half your recordings a significant improvement in sound.

The ability of a system to reproduce the perception of the space between the instruments and the hall, ambiance, while not one of the primary qualities, is possibly the most important in determining whether a system is reproducing all of the sound in the recording. Ambiance is the background low level information stored on the recording that gives one the feeling of being in a space and not in an anechoic chamber, and requires equipment that is both phase correct and quiet and will reproduce the least significant bit of digital or the shallowest groove modulations on a recording. Thus, at least to me the ability of a system to correctly reproduce the ambiance is the single most important method of determining its quality.

4. Source: Analog vs. Digital
Unlike many of my compatriots, at the present level obtainable in my system, I believe that their pluses and minuses in two channel reproduction are equal, just different, and could live with either with equal enjoyment.

Analog, especially master tapes but also the best vinyl played on a top notch system, still gives me a more realistic feeling of being at the recording venue, at least in the front half of the listening space. I am still unsure what gives analog the more holographic imaging which seems to fill in the space between and around the music, bringing the hall sound out into the room, enveloping one in the atmosphere of the recording venue. Whether it's the spatial information which is lost between the digits, or the noise or distortion inherent in tape or record playback, or a combination of the above doesn't matter; a well set up  analog two channel system will give you the most realistic front of hall, ambience information every time. In addition, at least to me and with my system, analog is more musical. It sounds more like what I hear at a live concert giving a "you are there" experience that two channel digital still can't accomplish. Maybe the analog noise more matches the natural sounds one is surrounded with at a live event compared to digital's, or the continuousness of the analog sound wave vs. digital's need to "fill in the bits" is more natural for the brain to decode.

On the other hand analog suffers from several problems. First the noise floor; while it can be very low with the best analog recordings from the best engineers on a top of the line turntable, one does have to listen through it to hear all of the information available. Old timers like me who grew up with tape hiss and vinyl's noises automatically do this and can actually perceive information that is lost with 16/44 digital, which has a maximum 96 dB signal to noise ratio compared to analog's 60 dB. But unless noise in the form of dither is added to the digital, the sound can lack the quality of space.  Remember, when one attends a live concert, even a classical string trio or piano recital, there is at least a 50 to 60 dB audience and HVAC noise floor which we perceive as natural.

Second, analog pitch is never perfectly stable. As it relies on motors with their inherent instability, and movement of tape or stylus in a groove on a never perfectly symmetric record, and without the ability to store information to minimize the above before amplification, wow and flutter is endemic to analog, but not digital. Again, old-timers have the ability to overcome this weakness of analog, but the more one does listen to pitch perfect digital, the more difficult it is.

Third, it does cost considerably more in finances, time and effort to obtain good analog sound. You may disagree with this statement, but there is the OPPO 983 DVD-CD-SACD player that for $168 can give very good sound. The least expensive analog rig with decent sound will probably cost several times that. At the other end, the most expensive digital system that I know of is the Esoteric top of the line transport, D/A converter and master clock which will cost less than $50,000, while there are several turntable-cartridge combo's that cost somewhere north of $150,000 without phono stage, and my Walker-Kondo-Vacuum State combo lists for about $65,000, significantly more than my $5600 Esoteric DV-60 player.

Digital now has a major advantage with multi-channel high bit rate recordings. Whether it may be DVD-Audio, SACD, or Blu-ray with DTS Master or Dolby TrueHD, one now has the ability to feel the hall experience in an almost perfect half-sphere around the listener. This space is different from analog's more intense holographic quarter sphere, but of equal value to this listener.

5. Solid-State vs. Tube Amplification
Over the past 30 years, I've had at least 20 different preamplifiers and amplifiers; everything from cheap solid-state FET to expensive Mosfets,  push-pull vs. single-ended tubes, low to ultra-high power Class A… to triodes to pentodes. I've had tube preamplifiers matched with solid state amps, solid state preamps with push-pull and single ended tube amps, and straight solid state and tubes. Digital sources have been anything from pure solid state factory units to ultra-modded tube output stages. I've learned the following:

a) Matching of equipment is more important than anything else. I've had relatively inexpensive solid-state components, such as my present Onkyo Integra 9.8 pre-pro which sounds great matched with my VacuumState tube amplifiers, and super-expensive tube preamplifier (name withheld) that sounded horrible with the same amps. How the component's strengths and weaknesses interact with each other will determine the final sound. Remember, no matter how expensive, no piece of audio equipment is perfect.

b) Tubes done properly are more musical than solid-state. While this statement was very true 25 years ago at the birth of solid state, it still holds up today. Tubes are naturally more linear that transistors or op amps, which have to be whipped into linearity by complicated circuits. As long as a tube is operated in its proper range, it is naturally linear. As a corollary;

c) The simpler the circuit the better. Every component that has to be added to a circuit will in some way damage the sound wave, be it resistor, inductor, capacitor, etc.

d) Lower wattage amplifiers with fewer stages and fewer output devices, usually sound better. 

      Thus;

e) If one can get away with it, low power, simple circuit Class A single-ended amplification, preferably with triode tubes, is the most musical.

      On the other hand;

f) Amplifiers need to be matched to the speaker being driven. Some speakers are very efficient and have very flat impedances over their entire frequency range, such as horns, and therefore can be driven to high levels with minimal wattage amplifiers.

g) On the other hand, many modern speakers built for flat frequency response, have very poor efficiency and impedance curves all over the place and require high wattage and high damping factor amplification. For these loudspeakers, for the sake of the environment and your wallet, solid-state (preferably Class A) is less expensive for the initial cost of the equipment, the electrical usage, and maintenance as it is rare to have to replace transistors vs. tubes. While a well lit amplifier with 20 tubes glowing a golden hue can warm the heart better than a fireplace on a cold winter night, in the summer it will drive either the air conditioning bill through the roof or you from your listening room. On the other hand, if it's cost no object, then a high power tube amplifier will put a glow in your room and your music.

h) While the new digital amplifiers have several advantages, including low initial and electrical usage cost per watt, quietness, high efficiency, coolness, and low weight for their wattage output, and have the tightest bass available, at least with the units I've heard so far, they still don't have the musicality of other amplification methods.

6. Loudspeakers
My first pair of speakers 45 years ago was a home built cabinet containing an 8-inch Radio Shack driver with a coaxial tweeter built to a size dependant on the wood available rather than any scientific parameters. They probably sounded horrid, but to me they were great. Until seven years ago, all of my  speakers have been factory built multi-cone units, including Yamaha NS 1000 monitors, VMPS Super Tower IIaR's, and B&W 801's, all of which were highly modified by me and others as none of them really satisfied completely. While I love the sound of large electrostatic and ribbon speakers, and many of the huge super-expensive cone units available, they all require high wattage amplification (see above.)

Since I'm of penurious Scot extraction, enjoy working with my hands and brain, and love the sound of single ended triode tube amps, and believe in active rather than passive crossovers with their ability to let more music through, for the past eight years I've been happy with seven self-built multi-driver straight horn speakers modified from plans of Bruce Edgar, of Edgarhorn fame. While single driver horns have the advantage of one wave front with a glorious mid-range, such as the various Lowther iterations, they do have the disadvantage of poor low and high frequency output. Even my friend, Steve Klein who swears by his single driver Beauhorns, has succumbed to using a tweeter and subwoofer to augment them.

Horns have the major advantage of very high efficiency and flat impedance curves when kept to their proper frequency ranges. Thus they can be driven for the most part with very low wattage Class A single ended output tube amps which are the most musical available. This also allows use of either fairly simple passive crossovers, or active crossovers with multi-amplifying, allowing each amp and driver only to have to reproduce its frequency range.

Horns also have the ability to reproduce from the quietest to the loudest sounds due to their efficiency. Due to the fact that they can move large amounts of air with minimal motion of the driver, they produce less distortion than a standard cone speaker which has to move much more of a distance or have a much greater surface area for the same loudness of sound.

Their major disadvantage is size, as their ability to output low frequencies is directly related to their length and the size of their opening. To even get to 50 Hz, the lowest frequency my largest horn reproduces, the woofer horn is six feet long with a 3x4 foot mouth. A 20 Hz. horn would have to be over 20 feet long and take up an entire wall for its opening. On the other hand one watt of amplifier power will produce 108 dB. And they can produce very high sound outputs at very low distortion.

Their second disadvantage is time alignment of the wave fronts from the various drivers for two reasons. Where electrostatics rely on one membrane and cones and ribbons tend to be very close in physical alignment, horns with their varying lengths and opening sizes tend to be difficult to align in space so that they are close to the same distance from the listener. Also, wave fronts tend to be slowed slightly as they travel down the horn, so the longer the horn the greater the slowing. Thus, one really needs a program such as WinMLS to do proper time alignment, but also the very critical crossover adjustments, etc.

More next month.