For convenience and easy access, I have now indexed all the tests so while at Youtube you can simply click on the time mark links to jump to any specific test of interest, or here, below, simply click on the Youtube image above
each description to watch the test/demo of it:
- sub-chassis ground strap to dissipate static charges [just a still photograph of it, no demo], reducing pops and ticks
- neutral balance tonearm (instead of typical stable balance) maintaining a non-varying tracking force even on dips/warps
- heavy platter for momentum (speed regulation) yet light enough to be driven with a precision, synchronous clock motor
An added perk of the neutral balance arm is the constant tracking force obtained even if the XA is relocated to a tilted shelf in the room.
- ULTRA low mass, acrylic headshell for low inertial mass in order to track difficult/imperfect records
- very rigid and inflexible, "box-construction" headshell design to minimize microscopic flexing (distortion) despite its low mass
AR's white paper "Skating Force: Mountain or Molehill?"- R. S. Oakley Jr., Audio magazine, Mar. 1967 summarized: Waveform tests show it's unimportant if using an adequate tracking force from the get go, however a DIY design like a weight suspended by a thread draped over a bent paper clip, attached to the arm, may be added for those who are still concerned.
- Dead accurate speed and very low wow & flutter, including actual stylus drag during the test. [Even with oxide on this one's pulley and a cheap, aftermarket belt instead of AR's original belt, which were frozen solid and then machined on both sides for precise surface uniformity.]
Despite looking flat, a closer examination reveals that micro warps (surface bumps/dips) exist on most LPs. This is why the AR-XA keeps its pivot height much lower than the competition in order to minimize "warp wow". A demo compares the XA pivot height to that of a $28,000 tonearm using a 1 kHz test tone on the CBS STR-100 test record with an artificial warp.
- immunity to shock and vibration hammer test.
- Acoustic feedback "howl" immunity even at VERY high playback levels and when mounting close to, or even ON a speaker, including immunity to incipient acoustic feedback distortion, preventing boominess and murkiness, found at lower playback levels with some designs
- Ultra low mass headshell/arm: McProud Test at 33 RPM. [WARNING:
May fling the arm off the record and damage the stylus on the competition!]
Full-size, NAB broadcast quality spindle diameter to minimize groove eccentricity wow.
Artificially induced 1mm eccentricity audibility demonstrated
THE FOLLOWING TEST REQUIRES EITHER SPEAKERS WITH GOOD, DEEP BASS IN A QUIET ROOM OR FULL SIZE HEADPHONES.
-3-pt. floating sub-chassis immunity to ROOM noise rumble, not reflected in a traditional rumble spec. [An ON/OFF demo of the suspension shows what it eliminates via spectral analysis.]
Nailing wood on the top plate [aka the "plinth"] demo!