#PRINTABLE MILITARY PROTRACTOR PDF FREE#

The graph is a visual representation of the columns of numbers on the left, which are a function of three specific tonearm parameters, effective length, angular offset, and stylus overhang as displayed in the tan colored cells, A3, B3, and C3.

The output values change in accordance with the equations listed in the instruction area below the graph when new numbers are entered into any of the yellow input cells. The default or initial input values are 228.6mm (9') for tonearm effective length and the IEC standard innermost and outermost groove radii of 60.325mm and 146.05mm, respectively. Outputs are angular offset, linear offset, stylus overhang, pivot-to-spindle mounting distance, inner null-point, and outer null-point. Inputs are effective length, innermost groove, and outermost groove. The calculator has three yellow input cells and six green output cells. Okay, so how does the spreadsheet work? Well, the easiest way to operate the spreadsheet is by using the Löfgren 'A' or 'B' calculator at the top of the spreadsheet page. Löfgren's 'A' alignment minimizes and equalizes the distortion peaks at the innermost groove, in-between the null-points, and at the outermost groove. The advantage of Löfgren's 'B' alignment is lower tracking distortion during more playing time at the expense of slightly higher distortion at the beginning and end of the record. In other words, Löfgren's 'A' alignment minimizes peak distortion while Löfgren's 'B' alignment minimizes RMS distortion. The difference between the two alignments is that Löfgren's 'A' alignment minimizes the weighted tracking error curve directly while Löfgren's 'B' alignment minimizes the area underneath the squared weighted tracking error curve. This weighted curve places more emphasis on tracking error for inner grooves than for outer grooves, which is representative of the actual distortion caused by tracking error. Baerwald even lists Löfgren's paper in his references.Īt the core of Löfgren's alignments lies the weighted tracking error curve, which is essentially tracking error per unit of groove radius. Baerwald, Stevenson, and others came along later, and each published alignment geometry equations which have been shown to be identical to those published by Löfgren, and yet they included no recognition that Löfgren had already published the same equations.

Interestingly, from all the reading I've done recently on the subject, it seems that Professor Erik Löfgren was actually the person who developed modern tonearm alignment geometry back in 1938. It is a two page spreadsheet-one page for Löfgren 'A' alignment and one page for Löfgren 'B' alignment. Y ou'll find an Excel file at the link located below this article. Thank you.Įxcel Spreadsheet To Make Your Own Protractor! We do get a bit of commission with each sale. It takes time and patience to get it just right, but the results are worth it! You know you have it perfect when both points are perfect without moving the protractor. It forward or back and see how it aligns on both points.

Need to do is mount the cartridge a bit loose and slightly move Mounted so that the needle aligns perfectly on BOTH dots without moving the protractor. In Use: The trick is to have the cartridge Home is where my turntable is and everyone should have a two point protractor.

#PRINTABLE MILITARY PROTRACTOR PDF FREE#

Free Protractor To Align Your Turntable Cartridge!

Printable military protractor pdf