Turntable Cartridge Alignment Protractor PDF – Download & Print

Löfgren A, also called Baerwald, is the right starting point for most systems. It equalises the three distortion peaks across the side, so no part of the record is favoured at the expense of another. Löfgren B and Löfgren C lower the average distortion instead, accepting a little more at the outer and inner edges. Stevenson places one of its two null points at the inner groove and suits listeners whose priority is the last tracks of a side. All four are available in the generator, and the chart it draws shows what each one trades.

Stevenson alignment sets one null point exactly at the inner groove radius, where the groove is most compressed and distortion is hardest to hide. Tracking error falls to zero there, at the cost of higher error across the rest of the side. It is the choice of listeners who care most about the final tracks. It also asks for the least overhang of the four geometries, which can help when a headshell offers little room for adjustment.

Löfgren C is the exact least-squares alignment: the geometry with the lowest average tracking distortion across the whole side. For decades only an approximation of it was published, and that approximation is what most tools label Löfgren B. Our generator computes the exact solution from the closed-form equations published by V. M. Jovanovic in the Journal of the Audio Engineering Society in 2022, alongside the three classical geometries.

A pivoted tonearm travels in an arc while the groove is a spiral, so the stylus can be exactly tangent to the groove at only a few radii. With the offset angle and overhang these geometries use, there are exactly two, and they are called null points. Everywhere else the tracking error is small but not zero. Choosing an alignment geometry is choosing where those two points sit.

They are three assumptions about where the music actually sits on your records. The alignment is optimised over that band, so the choice moves the null points and the overhang. IEC, 60.325 mm to 146.05 mm, is the international standard for the LP. DIN, 57.5 mm to 146.05 mm, is the older German standard, which allowed grooves to run closer to the label. Typical, 63 mm to 145 mm, is not a standard at all: it is a working convention for where the music on a normal commercial record starts and ends, since few records are cut to the limits their standard allows.

The trade is straightforward. A narrower band lowers the worst case inside it and raises the penalty for any record that runs past it. With Löfgren A on a 215 mm tonearm, at a reference level of 8 cm/s:

• DIN, 57.5 to 146.05 mm: peak distortion 0.28 percent across its own band, and 0.28 percent on a record whose groove runs in to 57.5 mm.
• IEC, 60.325 to 146.05 mm: 0.26 percent across its own band, 0.44 percent on that same record.
• Typical, 63 to 145 mm: 0.23 percent across its own band, 0.59 percent on that same record.

Choose IEC unless you know your collection well: DIN if you often play pre-1980s or densely cut records, Typical if your records end well clear of the label. The null radii depend only on this choice and the geometry, never on the length of your tonearm: 66.0 and 120.9 mm for IEC, 63.1 and 119.2 mm for DIN, 68.7 and 121.8 mm for Typical.

It is the straight-line distance from the centre of the tonearm’s vertical pivot to the centre of the platter spindle, and it is the only measurement an arc protractor needs. Most tonearm and turntable manuals state it directly. When a manual gives effective length and overhang instead, subtract them: pivot-to-spindle distance = effective length − overhang. If nothing is published, measure it with a good steel rule, centre to centre.

Overhang is how far the stylus reaches past the spindle when the arm is swung over it. Effective length is the distance from the pivot to the stylus. The three figures are tied together: effective length = pivot-to-spindle distance + overhang. An arc protractor sets overhang for you. When the stylus follows the printed arc at every point, the overhang is correct by construction, and you never measure it directly.

Yes. The list is a convenience, not a limit. Enter your pivot-to-spindle distance by hand and the generator will produce a template for any pivoted tonearm between 60 mm and 400 mm. Your manual is the authoritative source, and where it gives effective length and overhang, subtract the two. If you have the manufacturer’s documentation for a model we do not cover yet, send it to us and we will verify it and add it.

No. Alignment geometry belongs to the tonearm, not to the cartridge: the same template is correct for every cartridge that fits your headshell. What differs from one cartridge to another is only how easily it reaches the required position. Mounting-hole spacing, body length and stylus position decide whether the headshell slots allow the overhang the geometry asks for.

As accurate as the print. The geometry itself is exact: the null radii come from published closed-form equations, and the template is written as a true vector PDF, so nothing is lost to screen resolution or to rounding. We cross-checked our implementation against an independent implementation of the same geometries, and the agreement is at the limit of double-precision arithmetic, far below anything a printer or an eye can resolve. The variable is your printer, which is what the calibration marks on every template are for.

Print at 100 percent with scaling and “fit to page” switched off, then measure the two calibration spans on the sheet with a steel rule. If a measured span differs from the printed target, type what you measured into the generator’s printer-correction fields and print again. One pass is usually enough. The step is worth the minute: a one percent scaling error displaces the null points by about a millimetre. A4 and US Letter are both supported and the geometry is identical on either.

Photo paper is the best choice: its surface is smooth, so the stylus does not catch, and its weight keeps the sheet flat. Plain paper works if it is clean and unbent. Lamination adds durability at the cost of thickness, which lifts the stylus slightly above its playing height. If you laminate, use a thin film and measure the calibration spans again afterwards, since the heat can change the scale.

Set anti-skating to zero, place a record on the platter and the template over the spindle, then slide the cartridge in the headshell slots until the stylus rides on the printed arc along its whole length. Rotate the cartridge until its body or cantilever squares with either grid, then check the arc again. The three steps above cover each stage in detail.

Either. The template is drawn for both. The cantilever is what actually reads the groove, so it is the more exact reference, particularly if the stylus is not perfectly square in the body. The body is easier to judge and is what most listeners use, and on a well-made cartridge the two agree closely. The pair of fine lines flanking each grid’s centre line is spaced for a cantilever; the wider lines are there to square the sides of the body.

Anti-skating pulls the arm outward, which biases where the stylus settles and makes the arc reading unreliable. Set it to zero for the alignment and restore it, with the tracking force, once you are done. Parallax is the other common source of error: read the grid with one eye, directly above the stylus. The comb of perpendicular lines at the front edge of the template gives you a reference for a square viewing angle.

Usually nothing. The two adjustments are independent: slide for the arc, rotate for the grid, then re-check the arc, because rotating the cartridge moves the stylus a little. If it still will not square after two passes, the likely causes are a cantilever that is not straight in the body, mounting holes that limit rotation, or headshell slots too short for the overhang your geometry asks for. In the last case, a geometry with less overhang, or a different headshell, will resolve it.

Inner-groove distortion is the rise in audible distortion towards the end of a side. Two causes combine: the groove velocity falls as the radius shrinks, so the same music is cut into less groove length, and the residual tracking error of a pivoted arm produces its largest distortion where the radius is smallest. Alignment cannot change the first. It minimises the second, and Stevenson addresses it directly by placing a null exactly at the inner groove.

Whenever the cartridge is fitted or refitted, after a retip or a rebuild, after the headshell has been off the arm, and after the turntable has been moved. Between those events there is little to drift, since the geometry is held by screws. A yearly check is reasonable, mainly to confirm that nothing has loosened.

It works for any pivoted tonearm with an offset headshell, whether 9, 10 or 12 inch, because only the pivot-to-spindle distance changes. It does not apply to linear-tracking arms, which stay tangent to the groove and have no null points to set. Underhung arms without an offset angle follow a different geometry with a single null point, and the generator does not produce templates for them.

It is free, with no account and no email address required. Everything runs in your browser: the figures you enter and the PDF you create stay on your computer, and once the page has loaded the generator needs no connection.