Tonearm Database
Database 
Alignment Calculator Pro Overhang Shift Calculator
Alignment Calculator Pro
Enter the published data for your tonearm to compare it's alignment to optimized alignment geometries.
You may also customise the alignments to be compared by entering alternative geometry for your tonearm, or by entering the data of different tonearms for comparison.
Further optimize your alignment by entering alternative groove radii based on max/min measurements from your own record collection.
| Parameter | 205mm p/s | Lofgren A | Lofgren B | Stevenson |
| pivot to spindle (mm) | 205 | 205 | 205 | 205 |
| effective length (mm) | 223.61 | 223.61 | 224.1 | 221.6 |
| overhang (mm) | 18.61 | 18.61 | 19.1 | 16.6 |
| offset angle ° | 24.7 | 24.7 | 24.64 | 23.64 |
| linear offset (mm) | 93.44 | 93.44 | 93.44 | 88.87 |
| inner groove (mm) | 60.33 | 60.33 | 60.33 | 60.33 |
| outer groove (mm) | 146.05 | 146.05 | 146.05 | 146.05 |
| inner null point (mm) | 66 | 66 | 70.29 | 60.33 |
| outer null point (mm) | 120.89 | 120.89 | 116.6 | 117.42 |
| maximum error ° | 1.96 | 1.96 | 2.16 | 2.39 |
| maximum distortion % | 0.67 | 0.67 | 1.08 | 0.82 |
| average rms distortion % | 0.44 | 0.44 | 0.39 | 0.54 |
Note
- Figures for inner and outer groove radii relate to the limits of modulated grooves i.e. those with recorded sound
- Distortion figures are calculated from samples of tracking error in the modulated groove area
Comparison of alignment methods
Stevenson
A variation on Löfgren geometry optimized for low distortion at the inner groove at the expense of increased distortion elsewhere. compared to Baerwald or Löfgren B you will get lower distortion for the last few mm of the record
Baerwald
Identical to Löfgren A, minimizes and equalizes distortion at the three weighted tracking error peaks resulting in moderate distortion between the inner and outer grooves
Löfgren B
Minimizes distortion between the inner and outer grooves resulting in the lowest average RMS distortion at the expense of slightly higher distortion close to the inner and outer grooves
Term Definitions
Below is a simple illustration showing the relationship between the terms used on this page
Mounting distance
Spindle centre to mounting hole centre (normally the same as pivot to spindle distance)
Pivot to spindle
Spindle centre to horizontal pivot point of the arm
Effective length
Stylus tip to horizontal pivot point of the arm
Overhang
Stylus tip to spindle centre overhang
Offset angle
Angle between cantilever and a line drawn between the stylus tip and the horizontal pivot point of the arm (not to be confused with headshell angle)
Inner/Outer null point
The two points on the arc of travel at which the stylus is perfectly aligned to the groove i.e. null tracking error
Inner/Outer groove
The limits of the modulated grooves specified by IEC as 60.325 and 146.05mm and DIN as 57.5 and 146.05mm
Tonearm Alignment Calculator design and coding by JaS © 2009
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