Spectrogram and L/R

[Dan McDonald]

I'm working on a cassette I recorded in 1978 using a JVC portable stereo recorder (roughly state of the art for consumer use around 1978). At the time, I only had one "pretty good" microphone (Sony ECM-22) and one cheap dynamic mic (I believe it came with an older cassette recorder). Since the recorder was stereo, I used both mics, as I figured I might as well use whatever was available, and I could always use whichever track was better if I could tell the difference, and not end up any worse for the option.

In any event, I was just clicking on L & R with the spectrogram, and can't see any difference in the files. Does that mean there really isn't much difference, or does that mean the spectrogram uses both L&R even if you have highlighted left or right with the buttons?

Dan

[Craig Maier]

I am going to have to check that one out, but I vaguely recall that we sum the Left and Right channels together and feed them both into the Spectrogram. So, if you wanted to view the effect of one mike vs the other, you would have to do something like create two files with the file converter with one having the left track and the other having the right track and then performing the comparison. To make that job easier, you can print the spectrograms out and then study the differences in that way.

But, I will double check on my assumptions about the summing of the channels.

[Dan McDonald]

Hi Craig -

Thanks. I just checked using the split file method, and there's a pretty big difference between channels when viewed as separate files. One hits around 10kHz occasionally, the other barely makes it to 6.5 kHz, so I think you're right about summing them.

Dan

[Craig Maier]

That is the same test that I would have run, so that is the answer - - - sums the two channels.

As for the difference in microphone response, you might want to try to apply the paragraphic EQ 25 uSec Pre-Emphasis preset to the mic channel having only a 6.5 KHz response. That is a good one, because it is shelving. Perhaps use it as a starting point. Try to make the two channels have similar response to balance out the final restoration using that method. Use the Spectrogram to measure your progress.

Note: Use the Split and Recombine feature to operate on each track individually.

[Craig Maier]

Rick had this to say about the Spectrograph:

"The spectrograph sums them together normally but if you select the R only buttons or L only button you get the channel you select."

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My recollection is that the R only and L only buttons only work with WDM drivers, not MME's.

[Dan McDonald]

Interesting. I'll see if it works if I switch drivers.

Dan

[Dan McDonald]

OK - I figured it out.

If you click on L (for example) and then click on Spectrogram, you get the spectrogram for the Left channel. If you click on R, the right channel is highlighted, but the spectrogram doesn't change. If you click on both, the same thing (spectrogram doesn't change).

If you do the L channel, click on spectrogram, then click off the spectrogram, highlight R, click on spectrogram, it rebuilds and you just get it for the Right channel.

I was just assuming it'd rebuild if I clicked on L, R or both.

This is with WDM drivers. I didn't switch them to see if it works with MME or not.

Dan

[Walter]

Spectrogram-Wave Display

Is there a way to display audio wave forms above or below the spectrogram view in real time?
If not this might be something to add to next version.

[Craig Maier]

Right now, the spectrogram does not work in real time. We can consider that for the future.

[Dan McDonald]

I kind of like the static view because I can take time to examine the whole wav file. For real-time I just use the spectrum analyzer.

Dan

[Walter]

Spectrogram-Wave Display

I just want to display wave form and spectrograph at the same time.

[Craig Maier]

If you use classic edit mode, you can see both the time domain and spectrographic displays concurrently. The time domain display shows in the upper display while the spectrogram shows in the lower (destination) display.