TQWT Calculator

[chairforce]

Hello

I wrote an Excel sheet that allows the calculation of TQWT enclosures similar as the Needle.

The calculation is completely parameterized, therefore it can be used for any driver. It is meant to exchange data between the MathCad scripts of Martin J. King.

Compared to the Needle there are following differences:

1. The tube-diameter increases linear. As the Intercept theorem is used, the upper end of the divider is not at the center of the box but slightly moved towards the baffle.

2. The baffle can be removed.
The internal port and the internal top allows additional fixation. As the dimensions of both internal parts are used for the calculation of the length of the middle line it is not possible to omit those.

The external top and the external bottom are optional, but these two parts simplify the assembly of the box. Furthermore they represent extra material in the main direction of the standing waves.

3. The thickness of the baffle can differ from other components.

4.The Excel sheet contains a Helmholtz calculator for the slot.

The Helmholtz frequency of the port must be adapted to Fs of the driver (or the tuning frequency). The hight of the slot has to be chosen accordingly. The width of the slot is determined by the diameter of the driver and two bars.
The diameter and the length of the equivalent tube can be used in MJKs MathCad scrits for further optimizations.

I used the Huebscher formular to convert the dimensions of the slot into an equivalent tube.

5. In the list of parts there are some components (marked light/dark blue) that contain an allowance of 1mm or 2mm. That additional material can be sandpapered off after the assembly of the box.

Peter P.