The dictaphones have to be parallel and fixedly positioned or else signal / electricity connection and too wobbly tape loop problems may occur if they are moved. To secure the dictaphones, I make an acrylic platform with blocks that are manually adjustable. This is an approximate model (unit is mm; grey is acrylic and blue is iron bars; the thicknesses of acrylics are approximate : 3=3/8”,6=1/4”,18=3/4”):
On each side, the 700mm*100mm base is sandwiched by a 3/4” (~18mm) and a 1/4” (~6mm) acrylic of dimension of 150mm*20mm. The metal (indicated by blue) blocks the machine from moving to the sides.
Connecting the cables, I found that the audio jacks are slightly blocked by the metal bar if the bar is at right angle to the acrylic bars. Therefore, to prevent bad cable connections, the metals on the audio in/out sides will be moved away from the main part of the platform to fix the problem. The dictaphones are still well positioned to be parallel to each other.
Testing with the actual functioning, I discover that the loop should not be pulled too tight. If so, the loop wouldn’t travel at correct speed or it may even get stuck and stop travelling forward. Putting 2 spare acrylic sheets that push the platform centre downwards is just enough to solve this problem without extra cost.
There are no rings on the speaker cone I use for the interior speaker. If I just put a string through the holes it has, it doesn’t balance. I use 2 magnets with a centred hole the hold the string to a small piece of acrylic. The position of the speaker is adjustable, according to how the interior acoustics perform as the installation is set up. As for the microphone, 2 adjustable rings are fixed near each end of the microphone. Strings are put through the rings and held to another small acrylic piece to hang the mic. The small pieces are screwed to the top.
The acrylic box is then modified a bit to let the cables of the interior microphone and the interior speaker to go through. 4 screws are fixed to each corner of the top acrylic to keep the top in place.
The audio jack of the speaker lays outside of the box. The cables have to be carefully positioned to keep the transducers in place and balanced too.
Comments