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In the Forum: Audio Discussions
In the Thread: It’s mad, mad, mad... electricity.

Post Subject: Maybe not that easy to capture after allPosted by Lx_ on: 4/14/2011

Romy the Cat wrote:
Lx, this is very interesting. At the initial picture I posted you do can clearly see the difference in dynamic range. When I did what you did and went to higher resolution then you are right - the difference disappears. Dose the Wivelab is so screwed that it deforms the presentation in respect to graphic resolution. Then what the DC came from. You are right it does have DC but where it come from?! The most important I stat the files do sound drastically different, it can’t be explained by DC and we need to see objective data differences. I agree that the experiment need to be doe again with more methodologically clean condition, the DC at least shell not be there.

The Cat

Romy, I guess the difference in scale between the two signals in the initial picture does two things:

It makes the smaller signal look less dynamic; and as it happened, it was the bad signal that got the smaller rendering and looked worse, which seemed natural
It completely changes the way a very packed signal is drawn on screen, and changes how the signal looks like; I would not fault wavelab, this would happen for nearly all rendering software and is due to the pixel size: resolution on today's screens is quite good, but far from being enough in this case

As to the DC offset, I find it strange too obviously. However as it quickly disappears I am not too worried about it. Maybe this indicates a problem in the soundcard when starting the recording.

As far as methodology is concerned:

I would try to repeat the measures several times with bad electricity, just to see how much variation we get from the measuring process only (or from normal variation from playback)
I would use a signal with greater dynamics or louder so as to minimize the influence of noise from the recording equipment
I would use a signal with more HF (there is almost none here)

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