Subject: From the November issue of POSITIVE FEEDBACK (1/4) Date: 7 Jan 91 10:25:56 PST (Mon) From: ogicse!agora.rain.com!david@uwm.UUCP (David Robinson) The following article is from POSITIVE FEEDBACK, the newsletter of the Oregon Triode Society, and is Copyright 1990, all rights reserved. This article may be reposted or reprinted, as long as it is not resold, and as long as proper attribution of the source is made in full. Please keep this header in all copies made of this article. David W. Robinson Editor, POSITIVE FEEDBACK david@agora.rain.com ---------------------------------------------------------------------------- THE ABSOLUTE TRUTH Bob Carver What I am about to say may challenge some long-held beliefs about how things work in general, and audio works in particular, and what makes things sound the way they do. This first column will be about interconnects between the amplifier and the loudspeaker. While science is at the heart of electronics, long-perpetuated myths enshroud many of its basic principles. This column is intended to de-mystify several critical issues. Throughout history, science has been most threatening to those who make their living endorsing myths and magic, because myth and magic can be much more fun and exciting than science and reality. You shouldn't be surprised when many audiophiles will more often, or as often, or regularly, embrace myth and magic rather than science. Far more people will go to a magic show than will attend a science lecture. And far more people buy the National  Enquirer than Scientific American by a factor of a zillion to one. AN EVENING WITH TWO AUDIOPHILES Audiophile A and Audiophile B compare two amplifiers. They both agree that the Dynowhizmatic has a deeper sound stage and far better ambience retrieval. They are not hearing things; there really is a difference. Audiophile A attributes this to: 1) Hummongo Brand Wonder Capacitors, 2) the over one hundred pound weight of the amplifier, and 3) a magic brick that has been placed on top of the amplifier. Audiophile B knows that the frequency response of the Dynowhizmatic varies plus or minus 1db when measured at the loudspeaker input terminals because the amplifier output impedance has interacted with the input impedance of the loudspeaker. This has caused a frequency response variation of plus or minus 1db, specifically in the range between 100Hz and 400Hz where most of the ambient information lies. "Pish posh," snickers Audiophile A. "That's a microscopic difference! What possible effect can a plus or minus 1db variation in frequency response over a couple of octaves have on something as audible as ambience retrieval and sound stage depth?" Audiophile B goes to the blackboard, kept in another room to prevent live- end reflections, and writes the following: +/- 1db = 2db total variation 2 db = 1.25 ...or a 25% variation in voltage at the loudspeaker terminals. Now power (energy) varies as a function of voltage squared, so... 1.25^2 = 1.58 or 58% more energy delivered into the listening room in the 100Hz to 400Hz range, which is precisely the range where the ambience lives, both in live concert halls and recordings. "Uhmm. Fifty-eight percent more energy from a plus-or-minus 1db variation? Huh?" Audiophile A is suddenly interested. "That could be audible as better sound staging and ambience retrieval. One db. Never would have thought it." "Nah, bull shit. Even though it's got 58 percent more energy output because of the interaction of cables, amplifier and loudspeaker, and just because the 58 percent extra energy is in the range of 100Hz and 400Hz where the ambience is in both a live concert hall and in recordings, I don't believe that's the reason. I think the reason that the Dynowhizmatic amplifier has better ambience retrieval is because of the magic brick and the Humongo Brand Wonder capacitor. I'm unconvinced. The Dynowhizmatic amplifier absolutely blows away the other amplifier!" Audiophile A also remains unconvinced about magic bricks. He understands that minute changes in frequency response AS MEASURED AT THE SPEAKER TERMINALS have a direct effect on audible sound characteristics. A lot begins to fall into place. "That favorite amp of yours has a soft, silky high end when hooked up with Balls-o-Matic cables? A roll-off as little as 0.75db at 15kHz will result in a 20 percent reduction in high energy treble. Awesomely solid bass from that Gravitronic 5000 amplifier? Since many 4 ohm speakers exhibit an impedance jump to 45 ohms right at their resonance point and the combined impedance of the amplifier and the cables can be, say, 1 ohm at 40Hz, the resulting variations in frequency response and energy balance will increase ultra-low end power 55 percent in the 20Hz to 40Hz range. Very, very audible." FREQUENCY RESPONSE??? Uh?? This may be a hard concept for many of you to become comfortable with. At first it sounds like an oversimplified panacea, but what I've said is really true. ANOTHER INTERESTING PHENOMENON: Heated debates about speaker/amplifier interconnects have raged for decades. I'm not here to tell you or anyone that it's all in your head and that there are no differences. Instead, the wrong characteristics have been and are being scrutinized. No one denies that different kinds of speaker wire have different impedances. When you realize the importance of spectral energy content (frequency response) and that frequency response is the combination of the amplifier's output impedance and the speaker wire's impedance as measured at the speaker terminals, it's easy to understand how different interconnects can have an effect. In the middle ages, alchemists and magicians would use one magnetized disk to move another. They, and the people they amazed with this phenomenon, described the "levitation" as black magic. Centuries later, the effect was correctly explained as repulsion of magnetic poles. Science had replaced myth. This analogy directly applies to speaker interconnects. Yes, there are differences. No, they're not attributable to interweaving geometry, or diameter of strands, or dielectric makeup or the cost of the cables. The differences are only attributable to the pedestrian impedance of the cable and the way the cable interacts with the impedance of the amplifier. This impedance all occurs inside the normal audio band, not at mega-Hz or at gamma wave frequencies. And remember this: The overall makeup of the cable can and will change overall energy balance in various parts of the frequency spectrum by as much as 100 percent. That's science, not myth. HOW TO EXPERIENCE MANY DIFFERENT AMPLIFIER BRANDS WITHOUT HAVING TO ACTUALLY BUY THEM Step One - Go to Radio Shack and purchase several 20w resistors. Purchase them in the following increments: Approximately .25 ohms, .5 ohms, .75 ohms, 1 ohm, and maybe even 2 ohms. Buy a pair of each, one for each channel. Step Two - Connect, in turn, any of the resistors to the positive terminal of your loudspeaker and then the wire from the amplifier to the other end of the resistor so that the resistor is in series with your loudspeaker. What you will do in this experiment is to change the impedance of the cable and the effective output impedance of the cable and the effective output impedance of the amplifier. The interaction that the loudspeaker and the new impedance conforms to will modify the sound of the amplifier. That single resistor will be responsible and will modify all of the terms and descriptions that we all hold near and dear to our hearts: The warmth of the loudspeaker sound--its bass quality, its upper register definition, its sound stage dimensions. It will change the transparency of the sound stage- -its authoritativeness, its effortlessness, and its accuracy. Your job, after careful listening to each one of these resistors, will be to choose the one that gives you...well, that's a matter of taste. Do you want a warm, rich rolling bass, or do you want a dry-type bass? Do you like a forward sound with a mid-range that literally glows and floats, or do you like a mid-range that's recessed and makes the sound stage deeper and wider? Do you like the high end to be soft and silky or up front with lots of tinkly definition? Whatever your preference, you can change all of that simply by changing one of those resistors. So...give it a try. One more thing: If you believe in magic, you won't hear much change. If you believe in science, you will hear the changes that I've just described. Sometime in the future, let's hold a fun contest at one of the [Oregon Triode Society] meetings. I'll do a demonstration to illustrate what happens with interconnects when these changes are made. We'll use a pair of Silver Seven power amplifiers and my new Silver One all vacuum tube (not hybrid) preamplifier which sells for approximately $7,000.00. It's brand new and hasn't been released. It's really a beautiful preamp. [No objections here, Bob. And I have a feeling that the OTS Board and  membership wouldn't mind a bit... Ian, Larry, Richard, Alan: What say you?  We'll keep you all posted on this one, and get it on the calendar just as  soon as possible. --DWR] That's all for now. If I'm invited down again to give another presentation, we'll have some fun. I have a dynamite experiment and sound stage demonstration to do. 'Till next time, may you have many GMIAs*. Regards, Bob Carver * "Great Moments In Audio." ------------------------------ Subject: More from POSITIVE FEEDBACK (2/4) Date: 7 Jan 91 10:28:49 PST (Mon) From: ogicse!agora.rain.com!david@uwm.UUCP (David Robinson) The following article is from POSITIVE FEEDBACK, the newsletter of the Oregon Triode Society, and is Copyright 1990, all rights reserved. This article may be reposted or reprinted, as long as it is not resold, and as long as proper attribution of the source is made in full. Please keep this header in all copies made of this article. David W. Robinson Editor, POSITIVE FEEDBACK david@agora.rain.com --------------------------------------------------------------------------- THE UGLY TRUTH Charles Wiens Back in the early days of my audio career, I had the unbelievable good fortune of being yanked off the dbx, Inc. 3bx assembly line (where I was doing the firm more harm than good) and thrown into an empty room with a desk, an oscilloscope, and a budget. I was told to design a subwoofer. This came about as a result of making it known (as loud as possible) that I had read the vented loudspeaker works of A.N. Thiele and Richard Small and actually understood them! This revelation put me on a level just below God at dbx, since at that time (1978) no one on the planet understood the Thiele-Small equations. Frankly, I didn't either. However, I was sick of screwing up 3bxs, and figured that I could work through them, given enough time and equipment. I was right, but it did take a while. During this time I was not loved by the Chief Engineer, one surly Dan Talbert, for I came in with only an anthropology degree and he wanted the subwoofer project for himself. At any rate, since this was the company's first loudspeaker, I was visited on a daily basis by every door-to-door salesman in the country. This was an experience that I truly relished, since they all left car loads of free samples. Within a couple of months my office was heaven on earth; barely accessible without knocking over some strange magnet assembly from Sony, or tripping over the ever-present 30" EV woofer. One of these samples was a box of a dozen 2" drivers from Matsushita with the surprising ability to reproduce a bandwidth of 50-16,000 Hz within a 3 db window when placed in a very small enclosure (about 60 cubic inches). Naturally, its efficiency was only slightly above absolute zero, but it gave me a great idea for an experiment in ego-busting psychoacoustics which I aimed at the great Dan Talbert. At that time the dbx reference room consisted of a 1600 watt/channel amp built in-house, AR-9 loudspeakers, and a turntable from Linn-Sondek. After tweaking up a pair of these 2" specials as well as I could, I placed one on each AR-9, hooked them up, and waited for DT to enter. When those ominous footsteps approached, the tiny speakers were turned up to the maximum extent of their little diaphragms' excursion. Dan entered the room and immediately uttered the words I had dreamed of hearing for weeks: "Don't those AR-9s sound wonderful? Why can't you do that?" I never told him what he was actually hearing, but everyone else heard about it. The episode was good for many an after-work beer. Unfortunately, karma tends to even out our lives. Several weeks later I walked into a Cape Cod gift store with some of these same drinking buddies, and was struck by what seemed to be the finest sounding stereo I had ever heard. None of the components were visible, but the string quartet that was playing practically reached out and touched me from thin air. I could see the instruments, their placement in the room; I even thought that I could identify the sound of a Stradivarius. About the same time, I also discovered the source of this musical ecstasy: A small Radio Shack receiver and a pair of 4" car speakers (with whizzer cones, no less!) hidden amongst the pottery. Touche', Charlie. The point of these two experiences is simple. We will always hear what we want to hear. The finest audio equipment available today is indeed excellent. It is also extremely expensive, and perhaps often no better than its slightly modified '50s and '60s counterparts. I certainly believe in obtaining the finest components one's budget will allow, but bear in mind that enjoyment of the music is the most fun of all. I have seen many an audiophile's love of music turn sour when the rent can't be met or the phone is disconnected. Our should not be a hobby of ego, but one of enjoyment and relaxation. Be careful with your cash. ------------------------------ Subject: More from POSITIVE FEEDBACK (3/4) Date: 7 Jan 91 10:34:20 PST (Mon) From: ogicse!agora.rain.com!david@uwm.UUCP (David Robinson) The following article is from POSITIVE FEEDBACK, the newsletter of the Oregon Triode Society, and is Copyright 1990, all rights reserved. This article may be reposted or reprinted, as long as it is not resold, and as long as proper attribution of the source is made in full. Please keep this header in all copies made of this article. David W. Robinson Editor, POSITIVE FEEDBACK david@agora.rain.com ------------------------------------------------------------------------------ AUDIO TIPS John Pearsall As an installer who thought that he had seen everything, I can assure you I hadn't when I chanced to run up against a really intractable problem in Bellingham, WA, about a year ago. I had just installed a large mega-system with fine components, great interconnects, super speaker cable--the works. But we got a loud hum on all sources. I tried every ground loop solution that I knew, but to no avail. A frustrating four hours went into the detective work; it was definitely a 60 Hz hum, but from where? About the time that I was doubting my skill and sanity, the clouds parted and the gods smiled on me. The Perreaux tuner in this all-Perreaux system had a non-threaded coax connector, and the CATV (Cable Company) FM lead fell off. The hum stopped. Like a toothache that disappears, this brought comparable relief. I took out the meter and there it was: About 300 millivolts of raw AC coming in from the street pole, to be transferred to the chassis of the system. Six months later, I ran into a similar case in Tigard, OR, with about 180 millivolts on the lead. In both cases the cable guys were called and the problem was fixed in about ten minutes. Live and learn, huh? * * * Another subject: What does a crawlspace, garage, or unfinished basement have to do with the economics of installing a fine sound system? Here's what it can do for you if you have one of these under your listening room... ...what to do with wire is a bitch. It is always in the way. It is unsightly. It is expensive at best, and ridiculous when you have to go around the perimeter of the room. So--why not run it under your floor in the shortest and neatest fashion. Not only can you cut many feet off the cable cost, but it is so nice when the cable disappears from the living space. As in the usual case, plan very carefully, because splices are a no- no. * * * There is a good alternative to the above. Your amplifier(s) can be placed at the speaker end of the room if you can (A) get AC to them easily, and (B) drive long lines with your preamp output stage...that is, high current, low impedance out. They could be either balanced or unbalanced lines, but both are effective with the right driving source. And since only about 2 meters of speaker cable is needed, buy something really special. Now that mono- block amps are becoming more common, this drive scheme is probably ideal. Think about the concept a little for current or future equipment. * * * A better wire marking tag has shown up at the various retailers who sell bulk barrel food. It is like a bread tag, but is all white and has a 7/8" by 1 3/8" piece of card stock attached to it for writing. (I've found that a fine roller ball pen in black is best.) See if you can talk somebody out of a few dozen. * * * Do you want to de-gauss your moving magnet cartridge with a Flux-buster? Well, you can de-gauss the coil forms and pole-pieces in the body of the cartridge, but you must remove the stylus assembly so that you won't also de-gauss the tiny permanent magnet on the cantilever. As for MC cartridges: Just follow the directions, of course... * * * If you have a new Moving Coil cartridge, but lack the patience to break it in while having to listen to it, here's what I did. I mounted an Ortophon MC in a high quality, low mass arm on a Dual automatic. Using decent vinyl and turning it over fairly often, I put the 20+ hours on the cartridge in a few days of attended break-in. The Ortophon X3MC and the X5MC sound a bit strident until after at least 15 hours. However, I would suggest that you not break-in a really expensive coil in a real dog of an automatic. Make sure it is a pretty sophisticated one. If all else fails, go ahead and settle in the new cartridge the old way and just wait it out. * * * Now is the best time to tear the system down and clean everything. Use contact cleaner and carefully assemble or replace any nasty looking wire with the best you can afford. Now's the time to try the Tip-Toes, speaker spikes, damping feet, a new equipment stand, install a new FM antenna, special wire, AC line conditioning, buy a vinyl cleaning system, improve your storage for recordings and, in general, improve what you have for the indoor season. While you're at it, clean up that sloppy video system and enjoy a better picture, too. Wire quality makes a difference in video pictures and video recording quality, so invest a little money here, as well. That's all for this time--good listening. ------------------------------ Subject: More from POSITIVE FEEDBACK (4/4) Date: 7 Jan 91 10:41:15 PST (Mon) From: ogicse!agora.rain.com!david@uwm.UUCP (David Robinson) The following article is from POSITIVE FEEDBACK, the newsletter of the Oregon Triode Society, and is Copyright 1990, all rights reserved. This article may be reposted or reprinted, as long as it is not resold, and as long as proper attribution of the source is made in full. Please keep this header in all copies made of this article. David W. Robinson Editor, POSITIVE FEEDBACK david@agora.rain.com --------------------------------------------------------------------------- VINYL REFLECTIONS: HANDEL'S MESSIAH Larry Sturtz Ah, 'tis the season. As I write this there are only 37 days until Christmas. Since I traditionally do all my shopping on December 24th, that leaves plenty of time for a holiday diatribe on the entire bloated business. ["Uh-oh," mutters the Editor. "Look for cover, friends...LS is in 'curmudgeon mode.'" DWR] Just think, I'm in this lousy frame of mind and without the advantage of even one audition of "Jingle Bell Rock," et al. I shall spare you, however, and focus one what is for me a holiday bright spot. I am referring to the annual performance of Handel's Messiah by the Portland Baroque Orchestra. More info later. While my mind is on the subject, a brief review of recorded Messiah's seems in order. Let's start with Beecham's late 50's set on RCA LDS 6409, 4 discs. This golden era Soria set has 10++ sound according to Mitchell. That's the good news. On the bad side Beecham outdid himself in reorchestrating and adding parts for modern instruments. It's exciting and appalling and deserves a listen. The first cymbal shot is a shock, but the singing and playing are wonderful. In any case, acquire it for collectability if the price is right. Recommended as perhaps the third Messiah in a large collection. There are many sets done in the late 19th century "bigger is better" style. Large orchestras and even larger choruses dominate. Both Malcolm Sargent's and the Adrian Boult are prime examples. Not recommended. If you like this kind of Messiah go to a sing-it-yourself and at least participate. One of (if not the) first smaller scale, quick tempo performances was conducted by Hermann Scherchen on Westminster XWN3306. In spite of less than first rate singing and playing, the performance is involving. Sound is barely passable 50's mono. Worth a listen . In the 60's Colin Davis conducted the London Symphony, Heather Harper, Helen Watts, John Wakefield and John Shirley-Quirk in what was the benchmark performance for many years, Philips C71 AX300, 3 discs, also on cassette and rereleased on CD. A magnificent performance just now beginning to show its age in light of all the original instrument releases. If you're only going to have one Messiah you can do far worse. LP sound is a little grainy but listenable. In my case sound quality is not an issue; the performance is involving. A criticism often heard is that there is little ornamentation provided by the soloists. I'm not bothered. Listening to the same ornaments in a recorded performance becomes tedious after a few hearings. If ornamentation is your thing it is provided in two admirable sets, Charles Mackerras on Angel and John Tobin on british GFH. The latter is very difficult to find, but worth the bother. It was briefly available on execrable Protone cassettes. ["'Execrable' and 'cassette' represent a fine coupling of adjective and noun, opines the Editor. As always, LS, "the man with Living Presence," speaketh sound revelations...] While I don't recommend either of these worthy sets as "only" Messiah's, they are deserving of study--especially Tobin. The Argo set, D18D3, with Neville Marriner and the Academy of St.Martin-in- the-Fields wins the quick tempo award. The performance is based on the first London performance of March 23, 1743, performing edition prepared by Christopher Hogwood who also plays chamber organ. Razor sharp precision and superb singing make this set thoroughly recommendable. Typical Decca clear sound. An underrated set. Of the many original instrument sets we'll discuss four-the reason being they are the four I have; Hogwood, Oiseau D189D3, Pinnock, Archiv 423630, Gardiner, Philips 411041 and Christophers, Hyperion A66251. The last three are digital. In general I find Gardiner's tempos, soloists and orchestra preferable to the others. But, for reasons that escape me, he recruits a congeries of counter-tenors to take the alto choral parts. Their infernal hootings ruin the entire proceedings. The deployment of falsettists to substitute for a shocking lack of castrati seems at best ill advised. Seems sexist. If this feature bothers you less than me then this set is recommended highly. Pinnock takes a more conservative approach. The original instrument swells are less pronounced, there are only a few counter-tenors and the singers use a bit of vibrato even if the string players don't. The tension level is lower than Gardiner, not a plus. I guess I'm disappointed that Pinnock isn't Gardiner without counter-tenors. Oh well, somewhat reluctantly recommended as the first Messiah on your shelf. I believe that only a few LP sets were issued meaning CD's or cassettes are it. If Pinnock's digitalis puts you into arhythmia then Hogwood might resuscitate you. The best original instrument soloists including Emma Kirkby perform with the Academy of Ancient Music. Late analog sound. Thoroughly recommendable to escape Pinnock's digits with little compromise. Finally, Harry Christophers leads the Sixteen Choir and Orchestra in an emaciated digitalized performance which does zip for me but others have been more positive. My perceptions are precision and bloodlessness. Maybe you hadda' be there. These omnibus essays written for POSITIVE FEEDBACK have been about works I consider indispensable. In every case I've concluded by saying something like you can't have too many. Messiah is near the top of my can't have too many list. Even bad performances can't stop the magic. Handel's genius transcends. Hear as many as you can. Stuff your shelves with as many as you can afford. If you are in Portland, Oregon on December 15 or 16, 1990 take in the performance by the Portland Baroque Orchestra. You will not be disappointed. If you have access to Fanfare back issues try to find the series of Messiah reviews by John Bauman. They are scholarly and discuss differences in performing editions, compare performing forces and generally offer much greater depth on all fronts.