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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.

 

 

Arm 1

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 °

Arm 2

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 °

Arm 3

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 °

Arm 4

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)
Parameter LMF-1 Lofgren A Lofgren B Stevenson
pivot to spindle (mm) 222 222 222 222
effective length (mm) 237 239.296 239.749 237.418
overhang (mm) 15 17.296 17.749 15.418
offset angle ° 21.6 22.986 22.94 21.983
linear offset (mm) 87.246 93.44499999999999 93.44499999999999 88.873
inner groove (mm) 60.325 60.325 60.325 60.325
outer groove (mm) 146.05 146.05 146.05 146.05
inner null point (mm) 60.287 65.998 70.285 60.325
outer null point (mm) 114.204 120.891 116.604 117.421
maximum error ° 2.45 1.8 1.99 2.2
maximum distortion % 0.841 0.619 0.996 0.756
average rms distortion % 0.482 0.403 0.362 0.495



Please login to generate tracking distortion plots

tracking error °

tracking distortion

tracking distortion %

tracking 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 Definitions

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