Cartridge and TT Setup with AnalogMagik

Discussion in 'Vinyl Nutjob World: Turntable and Related Gear' started by ogodei, Mar 24, 2021.

  1. ogodei

    ogodei Headphone Heaven Gatekeeper

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    This is a write up of the Analog Magik Cartridge Calibration Software package. I'll review the package as a whole so you can determine if purchasing is worth it for you. I'll also discuss the methods used for the individual measurements so the more enterprising members here might determine how to achieve similar results with other equipment.

    Since every measurement gets a few paras below this post is pretty long. Skip to the bottom for the TLDR.

    What is AnalogMagik ?

    [​IMG]


    AnalogMagik ("AM") is PC software that uses an external soundcard and its own test LPs to generate test tones from your phono pre-amp. It then displays easy to use numerical readouts so you can adjust your cartridge and TT to optimize performance. Available measurements include:
    • Cartridge setup: Azimuth, vertical tracking angle (VTA), vertical tracking force (VTF), anti-skate, resonant frequencies
    • Phono-pre-amp setup: Loading, gain
    • General turn table measurements: Platter speed, wow & flutter, vibration
    The provided instructions and digital readouts make the effects and direction of your adjustments clear. For each test you're told what your target or goal is: Adjust the TT so the numbers get bigger, or smaller, or closer together. Though oscilloscope readouts are provided you can complete most of the adjustments without looking at them let alone understanding what they mean. You don’t have to be an engineer to use the software.

    The Package & Setup

    The package itself retails for $750 through dealers and includes two test LPs (one at 33 1/3 rpm, one at 45 rpm) and a USB hardware dongle. The software (which you download from the AM website after registration) won't run without the dongle plugged in.

    It requires an external soundcard which accepts line-level inputs from your pre-amp. AM recommends you use the ART USB Phono Plus external soundcard. It's a phono pre-amp as well but you don’t use it that way: You connect the line-level outputs of your own pre-amp to the line level input if the Art Phono, then the Art Phono into your PC via USB.

    If you use a different soundcard (and you can, I completed a round of testing with a Focusrite Scarlett) you should verify that gain levels between channels are equal. While you can complete all tests with uneven levels the numbers may look distressing. The Art USB doesn't let you vary the gain between channels and AM claims it has amplitude and phase differences (on average) of only 0.02 dB and 0.19 degrees, which they say is negligible for the tests.

    Perhaps knowing their customer, setup instructions are written for a six-year-old. Unfortunately they're also spread over several pages on the website and seem to have accreted as questions from users were answered. If you have a basic knowledge of PCs and TT setup you should be fine.

    The Interface & Tests

    The interface is intuitive with large readouts for failing eyes. I never had to make a guess at where things were. The only issue I encountered was a too small window for the on-screen instructions requiring me to scroll quite a bit to see everything. Not a problem except at first I didn't know more instructions were available.

    Instructions for most tests are usually clear enough though it helps to know a little about TT setup before coming into it. For instance, the test for Wow and Flutter failed to specify which track to play back. There's also a series of tutorial videos available at the web site and I occasionally had to watch to clarify what I needed to do. The videos are more geared at selling than anything else though.

    Cartridge Tests
    Azimuth


    The test LP includes left and right channel only tones at 1000 Hz. You play back the appropriate track and the Cross Talk and Phase Difference numbers are displayed. You're instructed to minimize the difference between the Cross Talk numbers.

    [​IMG] [​IMG]

    This process took a while and involved writing down figures, switching tracks, and clicking lots of buttons as numbers for only one channel were displayed on screen at a time. Layout could be better but honestly doing azimuth this way (and it's probably the right way) just takes time.

    This process is the same as is being discussed here and seems to be the more or less accepted standard. Interestingly, Phase Difference numbers are also displayed but no mention is made of them in the instructions. Other calibration software (Dr. Feickert for instance) takes phase into consideration when computing the 'best' azimuth. Anyone who fully understands phase interaction might find the numbers a useful bonus.

    Vertical Tracking Angle (VTA)

    This is the angle of the tonearm, which in turn determines the Stylus Raking Angle (SRA), which is the angle at which the cantilever (needle) contacts the vinyl. AM thinks the best measurement for VTA is when inter-modular distortion (IMD) from playback is minimized. You're instructed to play back a track with 60Hz and 7kHz signals interspersed at a ratio of 4:1, then measure the IMD from both left and right channels. You then adjust the tonearm angle until these numbers are minimized.
    [​IMG]

    Most TT setup instructions I've seen stop at telling you to level the tonearm. Following the instructs from AM I kept lowering the tonearm until the back of the cart bumped down onto the record. Hmmm. Dialing back on that I ended up with the tonearm … about level. So not sure how useful this test is.

    Vertical Tracking Force (VTF)

    This is the weight of the cartridge on the vinyl surface measured in grams. You measure this with a cartridge scale and usually go for a number in a range provided by the cartridge manufacturer.

    [​IMG]

    AM thinks the best VTF is where Total Harmonic Distortion is minimized. You play back two high and low frequency tracks (300 Hz, 7kHz), measuring the THD on generated by each track. You then adjust tracking force until the numbers are lowest and closest together on both tones.

    This test was a maddening experience on my TT and cart, and I still don’t think I have it in the 'best' position according to AM. At one point in the process the tracking was up to almost 4 grams, much higher than the cartridge manufacturer recommends. The instructions state 'Not all cartridge[sic] will yield meaningful results.' This test will need to be revisited.

    Anti-skate

    As the cartridge moves across the record and angle of the tonearm \ stylus changes, uneven force can be exerted on either side of the stylus from the sides of the grooves. Anti-skate mechanisms, longer tonearms, or linear tonearms are commonly used to counteract or minimize the issue. AM uses a sweep-tone track placed closest to the spindle on the LP to read total harmonic distortion between the left and right channels. It then instructs you to adjust anti-skate to minimize the THD number displayed.

    [​IMG]

    This test needs to be done after all other cartridge setup adjustments are completed. It's straight forward and adjusting anti-skate did make a clear difference in the readout.

    Resonant Frequencies

    Every Cartridge|Tonearm hardware combination has one or more resonant frequencies where the hardware vibrates in sympathy when certain frequencies are played back from the record. When this happens it adds to the volume of that particular frequency during playback. The upshot: The hardware vibrates when you don’t want it to and makes certain frequencies louder when it shouldn’t.

    [​IMG]

    It's almost impossible eliminate resonant frequencies entirely so general practice calls for a Cartridge|Tonearm combo where the peak resonant frequency occurs in the 8 to 12Hz region. Why that range? Most speakers are very recessed that low so the hope is the volume will be too low to hear. Someone other than me can chime with a better explanation for this if it exists.

    AM has you play back a track that starts at about 5Hz and slowly increases the frequency. As it progresses it displays the absolute amplitude at each frequency and records peaks. The resulting graph clearly displays these peak amplitudes, which are where your hardware is resonating and adding to the volume. You can then take action (tighten the connection, swap out tonearms or cart or whatever) to get your resonant frequencies in line.

    Phono-pre-amp setup
    Loading


    I'm not going to try explaining this other than to say there's an optimal loading impedance for each cartridge + wiring combination you run into your pre-amp. Most moving magnet cartridges specify a loading impedance of 47k Ohms, but moving coil cartridges vary greatly. If there's an impedance mis-match between the cartridge and the pre-amp the sound is either muddy or bright, to varying degrees.

    [​IMG]

    AM has you play pink noise (noise with equal energy per octave) and displays the frequency response, both raw and smoothed, between 20Hz and 24kHz. In the graph, muddy will be indicated by elevated bass or low mid frequencies. Bright will display as elevated treble. AM's 'just right' loading is when the smoothed frequency response graph is flattest. Adjustments to your pre-amp's loading can be seen in real time.

    While loading may be a matter of taste this method seems as proper as any other. Along with a variable head-amp or active SUT the measurement allows quickly finding the 'right' loading for a setup, which can then be used when purchasing a high-quality static SUT for use during playback. (Of course, you could do the same thing by ear even without the software.)

    Gain

    "AudioMagik believes the optimal gain level is the one which yields the highest Signal to Noise ratio." The software has you play a stereo tone at 1000Hz and measures Signal to Noise level for each channel. You are then instructed to vary the gain until the readout for each channel is highest.

    [​IMG]

    I can't argue with this approach. Some readers may suggest feeding a different or broader-band signal into the software and they could do so easily. Also, the tool could also be used to measure the impact of passive pre-amps or other gear in your chain since you're inputting signals at line level. No need to restrict this to phono inputs.

    General turn table measurements

    Platter speed


    The test LP includes a track of a 3150 Hz tone. You play it back and the software displays the frequency it sees. If the frequency seen is higher, your platter is too fast. If its lower, your platter is too slow.

    [​IMG]

    Wow & Flutter

    Wow and flutter are variations in the speed of your platter. They are otherwise known as frequency wobble. The effects are more or less noticeable to the listener depending on the severity of the wobble and the frequencies being played back but in general you don’t want any.

    [​IMG]

    AM has you play the 3150 Hz tone for a minimum of 30 seconds (meeting the AES standard) and displays real time and peak levels of any speed variations. It provides some generic advice as to how to minimize wow and flutter, including modifying belt tension, moving external motors, or adjusting idler wheels.

    Vibration

    Turntable vibration is measured by playback of a track with 60Hz and 500Hz signals inter-modulated at a ratio of 4:1. The current and average intermodulation distortion level between the signals is then displayed as a percentage for each channel. Since "IMD is essentially signals not recorded on the LP that are reproduced by the stylus…the lowest IMD% value is desired." AM suggests an optimal setup may have values between 1.5 and 3 percent.

    [​IMG]

    The AM tutorial shows how you can whap your TT or the platform it sits on while running this test and the numbers change. I got the same result, so this seems to work. As to whether this is the best way to measure vibrations, that’s above my pay grade.

    The Upshot of it all:

    The target customer for this product is old guys, with extra cash, who've invested a lot in their TT setup, obsess about optimum configuration, and don’t want to spend a lot of time figuring out how spectrum analyzers work. It’s a 90% fit for that audience as anything involving a Windows PC may require some configuration and some of the adjustments required for TT setup can be a bit tricky the first time around.

    But 90% is damned good. Screen layout is understandable for the novice but still caters to the engineer who wants to see graphs. Setup instructions could be a little better organized on the web site and test instructions in larger or adjustable type in the software. Remember those of us with bad eyesight. And the package goes through pretty much every measurement I've heard of. A few of the measurements are frustrating to adjust for but that’s the nature of beast.

    Are all the measurements necessary and if so couldn't they be done cheaper? Depends on your level of nervosa. You can find one-shot tests for Azimuth at a better price and that may be enough for most. Platter speed tests also abound. I appreciated the tests for anti-skate, resonant frequencies, and loading the most as I hadn't seen tests for these before.

    I have a couple of turn tables and change cartridges more frequently than many. This software does not save me setup time: Now I have 10 or so measurements to run through versus the three or four suggested by VPI. Essentially what this buys me is peace of mind that I did it right and playback is accurate. Maybe I can relax and listen to the music rather than fret over some measurement I read about on the internet.

    The cost is worth it to me but I don’t think you need to purchase their recommended sound card or a dedicated PC (unless you don’t already have a laptop). Perhaps you could create or replicate all the tests on a PC, soundcard, test LP a software spectrum analyser if you have the hardware and engineering chops already but that time would be worth far more than
     
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    Last edited: Mar 24, 2021
  2. wbass

    wbass Almost "Made"

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    @ogodei Thanks for this. Wondering if anyone else has messed around with this program and/or still uses it.

    I recall that @bazelio might have tried it out, though I'm not sure if he's on here much at the moment.

    I'm messing around with the more humble set-up/measuring tools (azimuth and anti-skate) on the Parks Audio Puffin right now. From reading various forums, I know that the effectiveness of these measuring devices (Fozgometer, Analogmagik) is debated (what isn't in this world?), and I also know that a lot of people just use an analyzer or a scope (or do it by sight and/or ear). I've tried that--a little, a free Mac program--and found the scopes mostly baffling. I should give it another shot though....

    Anyway, would be curious to hear others' thoughts.

    @ogodei Do you think this might be better moved to the azimuth thread mentioned above?

    Thanks again for this review.
     
    Last edited: Mar 24, 2021
  3. fluxbat

    fluxbat Rando

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    @ogodei, nice writeup.

    I have a copy and have tried it once so far. My setup is a bear to work with, so need to have the nerves calm and lots of time. Very easy to make it worse.

    I've compared it to Dr Feickert Adjust+. Analogmagik is more complete and easier to work with, especially as the disc is much higher quality with a centered spindle hole. Maybe someone has a lead on replacement discs for Adjust+. I haven't found one myself. There is no measurement for zenith. This will be coming in the next version.

    The challenge with all of these is in the adjustment. It is nice to have repeatable measurement, but as has been stated zenith, azimuth, SRA and tracking force are interrelated, making for a long tedious process, more or less dependent on your adjustment mechanisms or lack thereof.

    It is expensive for sure though the quality is first rate. It is easier to justify if you have an expensive cart and don't own or know how to use an Oscope.
     
  4. Biodegraded

    Biodegraded Friend

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    On Feickert's website they say they offer a 12" version, which I haven't seen for sale elsewhere. On their Adjust+ page there's a link to their order email (order at adjustplus dot de).

    There are ebay sellers still offering the 7" version, but depending on the batch it'll be a lottery as to how eccentric it is. Mine, bought a few years back from this Hong Kong seller, is terrible. Ok for anti-skate, azimuth and tonearm resonance, but hopeless for wow & flutter.
     
  5. ogodei

    ogodei Headphone Heaven Gatekeeper

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  6. fluxbat

    fluxbat Rando

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    I tried to order the 12" version from the Adjust+ page but received no response.
     
  7. ogodei

    ogodei Headphone Heaven Gatekeeper

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    They're still around, I had an email exchange with someone there last week.
     
  8. fluxbat

    fluxbat Rando

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    Thanks! They are alive!
     
  9. Biodegraded

    Biodegraded Friend

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    Minor thread hijack to alert people to two free PC utilities just for investigating wow & flutter: the WFGUI software wow & flutter meter (top of the page), and the Audacity wow & flutter visualizer plugin.

    The WFGUI meter will give weighted RMS or DIN weighted wow & flutter results from either a 3000 or 3150 Hz test tone:

    [​IMG]

    It's a little inconvenient as it won't directly take a file as input data, but requires a live feed into your computer from the phono-pre plugged into the line-in, from live speaker output via a microphone, or from a previously recorded file played back via mic or line. This means the program gives instantaneous results rather than a summary or average of the whole track (although it does give a summary every 10 sec in the line at top centre). The result shown here is from a synthetic file that's also shown in the Audacity plugin below (data spec in the file name on the title bar):

    [​IMG]

    This doesn't do any analysis, just shows the waveform - potentially useful if the 1 rev (1.8 sec period) record eccentricity fluctuation isn't so strong as to obscure any other components that might be present. The data can be exported and examined in a spectrum analyzer if you want to get more rigorous about it.

    In this example the meter gives a slightly worse peak result than expected from the perfect data in the file (0.0137% vs 0.00997%). To work the meter I played the file back through computer speakers and iMM6 mic into Schiit Hel, presumably introducing some noise. In a real-world recording from a turntable and test record, an error of this magnitude will be insignificant.
     

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