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Tonearm 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.

Name a name is required.

Arm Length

Pivot to spindle
Effective length

invalid format.min value 150max value 500a value is required. mm

Alignment

Lofgren A
Lofgren B
Stevenson
Custom
Overhang invalid format.min value 1max value 50 mm
Offset Angle invalid format.min value 1max value 89 °

Name a name is required.

Arm Length

Pivot to spindle
Effective length

invalid format.min value 150max value 500 mm

Alignment

Lofgren A
Lofgren B
Stevenson
Custom Overhang
invalid format.min value 1max value 50 mm
Offset Angle invalid format.min value 1max value 89 °
Name a name is required.

Arm Length


Pivot to spindle
Effective length
invalid format.min value 150max value 500 mm

Alignment

Lofgren A
Lofgren B
Stevenson
Custom
Overhang invalid format.min value 1max value 50 mm
Offset Angle invalid format.min value 1max value 89 °
Name a name is required.

Arm Length

Pivot to spindle
Effective length

invalid format.min value 150max value 500 mm

Alignment

Lofgren A
Lofgren B
Stevenson
Custom

Overhang invalid format.min value 1max value 50 mm
Offset Angle invalid format.min value 1max value 89 °

Outer groove radius

12" IEC 1958 / RIAA 1963 (146.05 mm)

12" IEC 1964 / DIN (146.3 mm)

12" JIS 1981 (146.6 mm)

10" IEC 1987 (120.9 mm)

7" IEC 1987 (84.15 mm)

Custom invalid format.min value 50max value 150 (mm)

Inner groove radius

IEC 1958 / RIAA 1963 (60.325 mm)

JIS 1981 (57.6 mm)

DIN (57.5 mm)

Custom invalid format.min value 50max value 150 (mm)

tracking error °

tracking distortion

tracking distortion %

tracking distortion
parameter Arm 1 Lofgren A Lofgren B Stevenson
pivot to spindle (mm)        
effective length (mm)        
overhang (mm)        
offset angle °        
linear offset (mm)        
inner groove (mm)        
outer groove (mm)        
inner null point (mm)
outer null point (mm)
maximum error °
maximum distortion %
average rms distortion %

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 definition

Below is a simple illustration showing the relationship between the terms used on this page

 

tonearm alignment

 

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
Many thanks to Seb for his assistance in putting this page together and to Graeme Dennes for his invaluable tonearm geometry analysis paper