Calibration - impedance - Reference calibration

[Calgerion]

Hello,

Sorry for such a beginners question, but did anybody fight with calibration setup?

I get from third measurement of reference ohm resistor Noisy result every time.

What should be the problem? Because with that kind of calibration I am unable to measure any speaker impedance, not even closer to reality :-) everytime it gets into big huge Noise mess :-)

 

[John Mulcahy]

Common sources of problems are the input format set to mono rather than stereo, selecting the wrong input channel (the reference channel instead of the one connected to the load) or not shorting the load connections for the short circuit measurement. The latter two tend to produce a short circuit calibration measurement that looks much like the open circuit measurement, rather than being close to zero ohms.

 

[Calgerion]

open circuit measurements gives completely flat curve.... Short circuit is slightly distorted but also quite flat. only reference last measurement goes crazy like that.

I will try to create new cable (thinner one, shielded), use different resistors - metalic instead of carbon ones.... just to eliminate human input factor.

 

[trobbins]

Can you do a separate loopback frequency response to each of the two inputs used for the impedance setup, and are they both noise free and flat (apart perhaps from some drop off at the frequency extremes if you went to 2Hz)?

 

[John Mulcahy]

.... Short circuit is slightly distorted but also quite flat

Doesn't sound right. Is the short circuit measurement close to zero ohm? Could post an mdat with the open and short circuit cal results.

 

[Calgerion]

Problem is Supersimple..... My both soundcards (integrated and external) have mono inputs.... I build cable to take sound from one chanell into mic L with loop from R. I didnt noticed that even on Laptop should be time to time Mono jack mic input..... Thats the life with DIY :-)

I built CINCH cable and used my external mixer for that purpouse :-) And its working well :-)

Thx all of you for willing to help :-)