Rocky Mountain Audio Fest 2014 • Cartridge Optimization for Musical Performance
During our various seminars over the years, we’ve swapped out amplifiers and complete cable looms, moved speakers and transported whole systems. At times it has looked (and felt) like something halfway between juggling and a high-wire act. This year's RMAF was different. The changes we were making to the system were almost invisible, yet in many ways they were more profound and more audibly apparent than anything else we’ve demonstrated, although that was far from a given. Preparing these seminars is a time-consuming and far-from-straightforward task. We don’t just have to choose a subject -- we have to develop a series of steps that audibly demonstrate it in action, steps that can be carried out in (what’s supposed to be) a carefully choreographed presentation that is both logical and convincing. At some point in that process, the inevitable doubts emerge. Can we do this, can we do it in the time available and if we do, will anybody be able to hear it? After all, working at speed, in a hotel room, under show conditions is a world away from the measured, cozy, controlled environment of your own listening room. Differences that are smack-you-in-the-face obvious at home can easily be eroded or obscured by the noise floor, acoustics, lousy, polluted AC supply or simple happenstance -- because believe me, if it can go wrong, a show is where it will go wrong and there’s nothing like an audience to usher in disaster. Taking all that into account, I had serious reservations about this year’s subject matter, especially as several of the manufacturers I approached for loan product told me in no uncertain terms that I was mad to even attempt it. Bearing in mind that we only borrow equipment from companies that we respect (for obvious reasons) that was a pretty sobering response. Two things made me persevere: the conviction that what we would be demonstrating was both innovative and worthwhile, and the existence of a Plan B, rather less ambitious than the proposal to perform the audio equivalent of tightrope walking the Grand Canyon. As it happened, that Plan B wasn’t required and things came together better than I had any right to expect. With the benefit of hindsight, there are sound reasons for that, but first, what exactly was the cause of all this anxiety? The seeds of this seminar were planted a year ago, when Stirling Trayle set out to demonstrate the audible benefits of the Acoustical Systems SMARTractor and its new UNI-DIN alignment geometry. As we discussed ways that he might make that presentation more effective we got into a more general discussion of cartridge setup -- or more specifically, how misunderstood the necessary skill set has become. Care and attention to correct alignment are only the tip of the stylus (if you’ll excuse the license) and the more we discussed VTF, SRA, azimuth and the other factors influencing cartridge performance -- and the more we discussed the mechanisms that we actually used to optimize them -- the clearer it became that, independently but concurrently, we’d both been working in the same way towards the same goal, even if we hadn’t recognized either that process or its ultimate destination. It really started with SRA. It quickly became apparent that, when it came to 'arm height, we were both listening for the same thing -- but that that "thing" was wildly at odds with both accepted wisdom and what little discussion there was in print. It was this that led in turn, firstly, to the notion that maybe similar, specific musical attributes or effects could be attached to each individual facet of cartridge setup; and then, secondly, to the concept of compartmentalized listening, the approach we subsequently set out to demonstrate at RMAF 2014. It’s almost time to cut to the chase and describe what we did and how we did it, but first there’s the small question of practicality. To a greater extent than any other seminar we’ve done, this one was going to be seriously dependent on the choice of equipment used, so first we’ll take a detailed look at the system assembled and the reasoning behind it. The equipment list:
The logic here is pretty simple. While these seminars are all about the subject being demonstrated, there’s an almost equally important subtext. This is your chance to get a handle on us -- how we hear, how we describe what we hear and how important we think it is. That’s why we always choose equipment we’ve recently reviewed (the Aesthetix and Wilson Benesch products) and why we explain what we hear each time we make a change. It gives you a chance to calibrate us as reviewers -- but also gives us a reality check. Stand in front of a room full of people waxing lyrical about the musical significance of the change you’ve just made -- a change they didn’t hear -- and see what it does for your reputation. When it comes to reviewing, it also tempers your willingness to praise too highly, exaggerate or write about differences you wouldn’t be able to demonstrate on a repeatable basis. How so? Just look back over the subject matter covered by the various seminars we’ve given and you’ll see that in each case they cover the most contentious issues we’ve raised on the site. Of course, one of those issues and the subject of a previous seminar is the importance of a coherent approach to equipment support and system cabling -- which explains the presence of the excellent HRS rack (currently under review) and the complete set of Nordost cables and QRT components. But there’s slightly more to the specific choices than that. Those carefully chosen foundation products (supports and cables) certainly open the window, allowing you to hear exactly what the system’s capable of, but isn’t the choice of such wide-bandwidth speakers and enthusiastically powerful amplification just asking for trouble? Well, yes and no. It’s true that all that power and bottom-end energy could easily cause problems, but it’s also essential to have good dynamic range, coherence and temporal integrity in order to show what we’re demonstrating. It’s a case of striking a happy balance. Likewise, we were keen to show that the differences we were showing were audible on real-world systems. Use several hundred thousand dollars worth of equipment and you rather undermine the impact (and potential relevance) of what you are showing people. It quickly becomes a case of, "Well I can hear it here, but I’d never hear it on my system at home." The whole point of our seminars is that they are general, applying equally to all systems, irrespective of price, and this one was no different. The Aesthetix/Wilson Benesch combination ticked all the boxes, delivering superb performance for the money while allowing us to keep things simple. This is exactly the sort of equipment that the "man on the Fulham omnibus" might actually own -- or, if not, he might realistically aspire to it. In addition, the Janus Signature in particular, with its fully configurable internal phono stage, offered some much-needed versatility, should Plan B become a necessity. But the real nub of the practical problem is focused on the choice of tonearm and cartridge. The thinking behind the seminar was based on experience garnered using expensive and exotic moving-coils, cartridges costing in the upper four- and lower five-figure price bracket. To be relevant, we needed to show that our approach would work with more modest pickups. It was also obvious that making multiple, repeatable, tiny adjustments would be an insurmountable challenge. The solution suggested itself: Once again we relied on the largesse of VPI and the flexibility of their JMW tonearm, with its facility to interchange armtops while preserving settings. But two recent innovations made things eminently more possible or practical: the advent of the 3D printed tonearm for the JMW has raised the performance bar significantly, giving added confidence in the audibility of the results, while the Soundsmith Counter Intuitive device makes small, repeatable adjustments a real possibility. We couldn’t have done this demonstration without it -- while once again, both are subjects that we’ve covered on the site.
Which brings us to the sticky subject of cartridges. It quickly became apparent that given the ground that we wanted to cover, we were going to need at least three identical cartridges -- delicate, expensive, fragile cartridges. Who in his right mind was going to have (and be prepared to lend us) those? This is where the quest for relevance worked in our favor. It not only suggested the use of more affordable cartridges, it also neatly circumvented the unfortunate fact that the more expensive a cartridge becomes, the fewer are built and the sample-to-sample variability tends to increase. Instead -- and true to our everyman, every system ethos -- we opted not just for more affordable cartridges, but deeply unfashionable moving-magnets as well. This was another high-risk strategy. The lower output and lower moving mass of moving-coil designs should make them more critical of setup -- and thus more capable of showing differences. But if our theory was going to work in practice, then it needed to work on all types of cartridge, while the fixed loading of moving-magnet designs at least removed one of the major variables from the overall equation. So our thanks extend to Clearaudio, who provided not just three of their Maestro V2 cartridges, but three with consecutive serial numbers! The Maestro V2 sits at the top of the company’s moving-magnet lineup and costs around $1200 -- so not exactly bargain-basement territory, but certainly well capable of responding to the benefits of improved setup. We started out with a "textbook" setup -- tracking force at manufacturer’s recommended value (or in the middle of the specified range if no specific value was stated), tonearm level and azimuth visually neutral. Overhang and offset were established using the single-point protractor that is supplied as part of the setup tools that come with the Classic 3, a device that uses well-established (and more or less standard) Löfgren B geometry. First order of business was to get familiar with the system in this form, for which we used the track "Ooh Child’ from the Valerie Carter album Just A Stone’s Throw Away [Columbia 34155] following that with setup favorite "‘Beaver Junction" from Count Basie's Farmers Market Barbecue [Analogue Productions AAPJ 023], its staccato opening phrases an acid test for timing, dynamic definition and rhythmic integrity. But this time, rather than listening to the overall sense, shape and sound of the track, we asked listeners to concentrate not on the notes themselves, but on the gaps between them. This isolation of a specific musical attribute is central to the process we’ve come to call compartmentalized listening. It allows you to concentrate on one aspect of setup and one aspect of the music at a time, which as will become apparent is the only way to proceed. With those two tracks now lodged in our collective aural memory, it was time to start ringing the changes -- which is where Stirling’s help proved invaluable. Able to rely on him to make the necessary changes I was left free to concentrate on explaining what we were doing and what to expect/listen out for. Our first change was to swap the armtop for one in which the cartridge had been set up using the Acoustical Systems SMARTractor. This precision alignment device has become a staple in my analog toolkit. Operating on the familiar spindle/pivot/single-point principle, its structure and execution allow users to achieve far greater accuracy as well as choose between any of five different geometries. We set up the armtop in question with Löfgren A, a curve that uses identical math but different input data to the VPI’s Löfgren B, differing mainly in the placing and spacing of its null points. Given that we were playing track three of four, any differences are further minimized. With all other parameters the same (VTF, VTA/SRA and azimuth) we replayed the Basie track, the more precise alignment delivering a much clearer, crisper and more dramatic performance. It was as if the edges of the notes had drawn in, their energy becoming much more focused, but at the same time making the precise size of the gaps between them much more obvious, improving dynamic range, rhythmic shape and the sense of phrasing -- simply from getting the stylus tip closer to the perfect position. Next, we swapped the armtop again, this time for one set up using the SMARTractor’s own UNI-DIN geometry, possibly the first real development in or alternative to established cartridge alignment math since Baerwald did the initial work in 1937. With the other parameters still set the same, we played the Basie again, with yet another change in presentation. Now the sound was more fluid, the passage from one note to the next more natural, the shape of the phrasing and the impact of the timing more apparent, as was the clear sense that Basie was placing his notes, allowing the piano to settle between the short phrases. Along the way it had lost a little of the dynamic impact and crisp separation of the Löfgren alignment -- but that was really the point. It doesn’t matter which you preferred (for me, it’s the UNI-DIN), the important thing is that they were musically and sonically distinct enough that you would have a clear preference one way or the other. Which is the same as saying that the geometry you choose when you align your cartridge matters. Look at the different curves (Löfgren, Baerwald, Stevenson, UNI-DIN) and you’ll note that one of the major differences is the positioning of the null points. Now consider the records that you play and specifically the way that they are cut. Early Deccas as an example, tend to have very wide cuts and limited groove land around the label, accounting for the preference amongst Decca collectors for Stevenson alignment, with its second null point so close to the label -- a position which also coincides with the massive modulations of many orchestral finales. Compare that with an album like Rickie Lee Jones’ eponymous first album (cut in 1979 -- [Warner BSK 3296]) with its six track, 21-minute first side. Even cut close to the label, the engineer felt the need to reduce the levels on the final track, "Last Chance Texaco" -- at a point where the Decca engineers of a two decades earlier were pushing the limits. Each geometry does sound different, but which you prefer will depend as much on the records you play as on the curve itself and a little experimentation will pay dividends. Having established that audible and musically significant differences exist between the various geometries, it was time to look at the other major cartridge-setup parameters -- starting with VTF. For this, we worked with the UNI-DIN-aligned armtop, if only because both Stirling and I preferred it over the Löfgren A. We started with the tracking force set at the Maestro V2’s recommended optimum value -- 2.2 grams (within a stated range of 1.8 to 2.6 grams). We used another Basie track, "Way Out Basie," characterized by its fluid walking-bass intro and stabbed piano chords. This time, we asked listeners to concentrate on the pitch steps between those progressive bass notes and the predictability of each piano chord’s arrival. Having played the track again, we now used the Counter Intuitive device -- an eccentric, low-mass auxiliary counterweight which sits over a grid scale to allow precise and repeatable changes of VTF and azimuth -- to alter the VTF to our preferred value. Playing the track again, those bass steps were far more positively defined, their pitch clearer and more secure, while the piano chords weren’t just more predictable, their weight and attack were now apparent. You could appreciate how Basie first backed off and then leaned into the chords, adding weight and attack as he built to the brass entry. Now the track had both a sense of purpose and direction. The rhythm took on a new urgency and the structure became a natural progression, leading to that first brass tutti. That’s no small difference, summing up in a single instance what big band music is all about. What was the revised VTF value? In this case, 2.55 grams -- but don’t draw too many conclusions from that. Not only is this value almost abnormally high, it underlines the fact that cartridges vary and that the preferred value might just as easily be below the manufacturer’s recommendation as above. How critical is VTF? We increased the value again by 0.05 gram (to 2.6 grams, the manufacturer’s recommended upper limit) and played the track again. All the extra focus, energy and clarity disappeared, with the notes sounding rounded, heavy and turgid, lacking attack and dynamic range -- so don’t be tempted to overdo the VTF. Tiny changes can have quite dramatic effects on the sound, so proceed slowly and be prepared to work backward and forward around a mean point. Why should VTF have such a dramatic impact? While it’s impossible to be sure, our thinking is that it’s a function of the generator itself. As you adjust VTF you alter the cartridge-ride height and thus the angle of the cantilever. That in turn alters the relationship between the magnet and the coils around it -- or vice versa in the case of a moving-coil cartridge. Either way, the nearer the moving element is to the neutral position the better. Move it away from that point and both the suspension compression and the electromagnetic interaction will start to vary, damping the movement and altering the peak value of the signal generated. Get the moving element as near to the neutral position as possible and you afford it the greatest freedom to react and the widest range of reaction -- which is exactly what it sounds like when you get the VTF spot on. Next parameter to consider is VTA/SRA, in many ways the most contentious adjustment of all -- from disputes over what we should call it to fundamentalist attitudes that assert on the one hand that it really doesn’t matter and on the other that there’s one true value and only one. Even amongst those who claim that it’s a critical factor there’s no agreement as to why. Personally, I don’t care why VTA/SRA matters. What I care about is whether it does and that is easy to demonstrate. This part of the demonstration differs from all the others in that it discards the standard A/B comparison format. Instead, taking advantage of the VPI’s ability to adjust 'arm height on the fly, we selected a track (Eleanor McEvoy’s "Got You to See Me Through" from Yola [Mosco Vinyl MOSV 102]) and played it adjusting the VTA/SRA as we went. We started with the setting five graduations low on the VPI scale, brought it up to our preferred value, took it up to five high and then back through the cycle, each time telling listeners what setting they were listening to. What should you listen for? Much is made of VTA/SRA’s impact on soundstage dimensions and focus. The problem is that these characteristics are hard to define, hard to pin down on a repeatable basis and often synthetic -- so how do you know when you’ve got the setting right? The answer is simplicity itself -- it gets louder. Vary tonearm height during play and you’ll hear the sound literally getting louder and then softer. At the same time, you’ll hear the rhythm locking in, becoming crisper, more purposeful and making more sense. Sure enough, playing the track, as Stirling raised and lowered the 'arm it was just like turning a volume control -- a volume control that adjusted temporal focus at the same time. The music didn’t just gain level, it gained dynamic and expressive impact too, adding significantly to the sense of performance. I think it’s fair to say that most listeners were absolutely astonished. Could VTA/SRA really be that simple? Yes, it really is! It’s also that musically important. How big an adjustment were we making? A quick bit of arithmetic suggests that the thread on the VPI tower adjusts the height by 0.9mm per turn. With 100 graduations around the scale, that means we were altering 'arm height by ±0.045mm -- considerably less than the difference in thickness between 120-gram and 180-gram records. And let’s just reiterate that these were seriously easy differences to hear -- once you know what to listen for. Of course, the VPI 'arm makes such fine adjustment simplicity itself, while the more extreme the stylus profile the more critical it becomes. The Lyras, Titan i and Etna, both react to changes of just a single graduation, the Clearaudio Goldfinger Statement to shifts of two graduations or less. It’s one of the reasons that I’ve used the JMW tonearms at home for the last decade or more -- and why the other 'arms that I also use consistently (the Tri-Planar and Kuzma 4Point) both offer the same facility. I change VTA/SRA on a record-by-record basis, a fact that most listeners find ridiculous -- until they appreciate just how big the musical differences can be and, given the right 'arm, how easy it is to do. Sadly, not all 'arms make things this simple. Our final parameter for adjustment was azimuth, again a simple task thanks to the Counter Intuitive. Again using the Eleanor McEvoy track, we played it with the azimuth just off and then again with the setting correct. This time we asked listeners to concentrate on how grounded, or rooted the sound seemed. Initially rather insubstantial and aimless, with the azimuth spot on, the music had a significantly more solid, planted quality, almost as if it had been locked to a solid foundation. It sounds like a simple change, yet in many ways, this was the biggest difference we demonstrated -- yet the actual adjustment was half a graduation of the Counter Intuitive scale. Bear in mind, too, that the Delrin arc of the Counter Intuitive weighs a fraction of the total of the actual counterweight itself. Why the huge difference? Partly because azimuth matters -- and partly because it was the final step in the process, closing the circle. As a number of listeners were quick to point out, it’s impossible to adjust any one parameter without affecting the others. Adjust VTF and you alter VTA; adjust 'arm height and you alter overhang -- and so on. Which is why, if we started at first base, what we demonstrated amounts to reaching second base. The next stage is to repeat the process, working with VTF, SRA and azimuth in even smaller increments, before revisiting alignment. That gets you to third and subsequent cycles will spiral in, closer and closer to the perfect setting (and home plate). By compartmentalizing each parameter and what you listen for when adjusting it, we make the task manageable, while each adjustment drags the others with it, closing in on a more and more musically precise solution. How close does second base come? Playing the Valerie Carter track again, it was brutally obvious just how far we’d come, in both musical and sonic terms. Now it was obvious what a great voice Carter had, the stellar quality of the "West Coast All-Star" backing band and just why this disc is considered a hidden gem. After all, who else could call on Jackson Browne and Little Feat to play a supporting role, with Deniece Williams and Linda Ronstadt on backing vocals? Starry stuff indeed -- and for once it really worked, especially now that the record player was up to the task. Now consider what it would sound like with a home-run setup. The other factor that we didn’t touch on is bias -- anti-skate -- compensation. One beauty of using the JMW tonearm is that it treats bias in an almost cursory way, simply using counter tension in the leadout wire to apply the necessary inward force, while the reduced rate of angular change introduced by the UNI-DIN geometry reduces the bias requirement anyway. Unfortunately, every approach to bias compensation is flawed, and the effect and extent of those flaws differs across the record. It’s not that bias isn’t important, more that its impact will be system and tonearm/cartridge dependent. However, having got the hang of the compartmentalized approach to setup, pinning down its characteristic signature and incorporating it into the setup cycle should be pretty easy. As a general rule, just don’t overdo it. When it comes to bias settings, less is often more -- especially if you use the UNI-DIN alignment. Of course, many of you will have tonearms that offer a limited range of adjustment. The Rega 'arms eschew VTA/SRA completely, while almost all UK-built tonearms seem to think that azimuth is irrelevant -- or at least, that it’s somebody else’s problem. Assuming that a cartridge manufacturer is going to get his styli perfectly aligned on a consistent basis may be the easy way out, but reality demonstrates just what a leap of faith that is. In the meantime, just working with alignment VTF and bias can deliver remarkable gains, while the awareness of just how critical cartridge setup really is should inform any future purchases or upgrades. So far so good. I can imagine a listener sitting through the presentation, getting a handle on the process, the audible differences and the overall benefits. But once you get home and approach your own turntable, with its expensive tonearm and exotic (for which read fragile and expensive) moving-coil cartridge, things might not seem quite so straightforward. What do you do then?
Answer: call an expert. The other reason I asked Stirling to help out with this seminar is that he is himself a very real part of the process -- not just developing what we showed, but applying it in practice. With the demise of so many brick-and-mortar dealers (and the dissipation of the analog-setup skills that used to be so central to their business), finding a reputable, qualified person to set up not just your record player but your system as a whole has become increasingly difficult. Partly as a direct response to that, we are seeing the emergence of a new class of audio professional -- the system optimizer. These are people with extensive experience when it comes to setting up systems, that you can hire to come to your home and do just that. Anybody who sat through our RMAF seminar got a firsthand lesson on just the bare bones of what somebody like Stirling can do -- just how much performance is probably lying unrealized in your system. Like I said, that was just second base -- with a $1200 cartridge that we were messing with at least twice a day, so that even the "optimum" settings were less than precise. Hiring somebody like Stirling to come and work on your system could just be the best (and certainly the most cost effective) upgrade you’ve ever made. So much so in fact that we’ll be reviewing his services shortly. In the meantime, you can contact him at Audio Systems Optimized, (707) 494-5482, stirling.trayle@gmail.com. On which note it remains only to thank Stirling for his
time and efforts, and to recognize the generosity of all those manufacturers who supported
our seminars by loaning equipment, time or expertise. Also, many thanks to all those who
took the time to sit through the seminars: We hope you found them interesting,
enlightening or at the very least, provocative. Until the next time. . . |
