Trouble Shooting

   Problem: My tester does not calibrate and always measures about 220ohms
This symptom usually occurs when XP compatibility is used. In this case improper settings cause the voltage and current channels (left and right) to measure the same value. Either disable compatibility mode, or set the device for 2 channel 44100 Hz operation with either 25% or 3% levels.

Calibration All
   Problem: My tester measures 300 ohms (or more when the drive level is set < 100%) and indicates clipping.
Check the test leads and/or load for an open circuit. To find out which test lead is bad, short the tester terminals using one then the other test lead.

Measurement All
   Problem: I don't understand the 'A' and 'B' Measurement and Reference Signals.
The ratio or db(ratio) can be calculated between two signals. Internally these signals are grouped into 'left' and 'right' signals that come into a 4:1 mux switch selecting the line, microphone, LoZP and HiZP ports (HiZP for WTPro enabled). Additionally, response can be calculated against the internal math reference. The test signal appears at both line outputs. The "A - Measure" (input) channel can be a microphone or line input, as selected on the Setup menu. The "B - Reference" channel requires an external loop from line out to line in.

Measurement Signals ST/WTPro
   Problem: I can't figure out what signals are being processed.
The FFT/Oscilloscope window shows the left and right channel before processing. This is a great way to hunt down many things. Just be sure the TS control window is open as this window has the base audio conversion routines attached to it.

Measurement Signals ST/WTPro
   Problem: The 'A' and 'B' selections do not always update but clicking on those settings a second time updates them.
This is a graphics update problem and has been fixed in beta release 3.04b.

Measurement Signals ST/WTPro
   Problem: If I define an impulse time window (area between the tick marks) in the Impulse Control Window and then close the Impulse Control Window, the effect of applying the time domain window on the frequency domain disappears.
This is by design.  If the time delay to the speaker changes, the time window will likely become invalid.  Likewise, if an SDFT measurement is being used to see room decay, it is easy to forget the window is active.

Impulse Control Window ST/WTPro
   Problem: Fast / Slow updates: I seem to be picking the wrong buffer sizes.
Small buffers provide fast updates for sinusoidal tests while large buffers work well with the real time modes. Not all PC's have the same capability so some experimentation will help.

Buffer Sizes All
   Problem: The Zobel Calculator does not always find an answer.
No solution is possible when the original phase of the solve at frequency is less than zero (a negative capacitance would be needed).  A message now alerts you to this fact.

Zobel Calculator All
   Problem: I tried the quick start response and it worked, but when I tried to use an amplifier all I get is noise.
The RCA patch cables provide the line out to line input loop back. A patch cable is used allowing this path to be broken and then used for testing low level devices like a preamp. Without the patch, the line-in reference is missing and the response is undefined.

Zobel Calculator ST/WTPro

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