HP-97/67 HI FI Pac Part 3 Loudspeaker BASS-REFLEX

[plore90]

This is a simplified calculation version for HP-67/97 calculators for the Bass Reflex Box Calculator (max. flat amplitude) with the possibility to customize Vb (Box Volume). This is the link to the site from which I extracted the formulas for the calculation.

https://web.archive.org/web/202208160200...s/BRH.html

The steps to follow are very simple. Attached to the zip file HP6797_BASSRFLATRESPONSE.zip you will find, in addition to this manual, the list of the source program in pdf format and a card in .hp97 format that can be used with the HP-67/97 emulator from LIMPIDFOX which is free.
1) First you have to manually store or read the corresponding data card with the previously saved driver data.
The data to be stored in the registers are the following:
Fs(Hz) STOA; QTs STOB; Vas(Litres) STOC; Sd(cm^2) STOD; Xmax(mm.) STOE.
2) Perform the following actions in sequence:
Press A to calculate the volume of the Box in litres.
Press B to calculate the cutoff frequency F3(Hz) at -3dB.
Press C to calculate the frequency of the Box Fb(Hz)
Press D to calculate the vent pipe diameter Dv(cm.)
Press E to calculate the length of the vent pipe Lv(cm.)
Press f a to calculate the Qbox quality value
Press f d to calculate the Ripple in dB of the response by system.
3)At this point you can enter a custom value for the volume of the Box (in litres) by typing New Value Vb STO1.
Press f b to calculate custom F3(-3dB)
Press f c to calculate the custom Fb of the box
Press D to calculate the custom vent tube diameter cDv
Press E to calculate the custom vent tube length cLv
Press f a to calculate the custom QL quality value of the Box
Press f d to calculate the custom Ripple(dB) value of the system response.
4) At this point you can enter a new Volume (in Litres) custom value, always storing with STO1 and repeating the calculations from point 3) or automatically recalculating the value of Vb and the other unknowns as in point 2).
To choose the calculation for a new driver, go back to step 1).
Thanks for the attention
plore90