Some questions

[Cintaku]

Could John or Glenn put a bit more light on this? I have calibrated Steiner Amplifier (patch cable IN with phantom switch ON and 4.5m cable connected to R output) and the curve is beautiful flat (only -1dB at 20Hz and -1dB at 20kHz). I was able to set IN and OUT level at 12dB.
Saved the file under soundcard and moved onto levels unplugging Right OUT and plugging ECM800 mic to it. That's where things get weird (for me anyway):

When doing levels and far left goes to -12dB I am unable to get gain IN to the same level. If I try it oscillates. So I had to reduce -12dB does to -25dB but the volume goes down too so making left and middle bar equal is a struggle.

When I go to measure and check levels sometimes it shows green OK but when I do sweeps graphs Y-axis show +165dB peak (average 150dB). Trusting results is problem under such circumstances because after sweeps are done two types of messages come up (level too high or too low).

1 - I usually listen to music at +75dB but how do I know sweep is not overpowering SPL or underpowering SPL when graphs are around 150dB levels

Should we do levels just with 1kHz and check it with SPL meter instead of using microphone ECM8000 and pink noise?

2 - Another issue is time. Steiner allows you to choose internal loopback which is ON. But times (waterfalls, spectrogram etc) show times close to 1 second. A message tells - "with zero offset".
Once again how can I get confidence that times measured (decays) are actual times?

3 - How do you attache pictures without needing http://?

 

[John Mulcahy]

You don't need to match levels when using a mic.

To get sensible SPL values calibrate the SPL meter.

You should not use any form of internal loopback or monitoring. Times in waterfalls are relative to the impulse peak.

Pictures can be attached by dragging them on to the post or using the file attachment options.