Reader Question: Why Do I Only See Changes in Spectrum View?

Reader Question: Why Do I Only See Changes in Spectrum View?

I have a little question about the Howard Page method of tuning that you recommended previously. I have been trying to employ this method when tuning and though I can see my EQ changes in spectrum mode, I see no changes to the magnitude and/or phase response. I have tried huge, obvious sweeps…. Nothing..

Any advice or answers for this? Things are routed correctly (I triple checked and can see changes in the “spectrum”) and my boss has no explanation.

Appreciate your time and expertise!

Corey 🙂

 

Hi Corey –

Remember that unlike a spectrum analysis, a transfer function shows the difference between two signals. More specifically, it shows how the “measurement” signal compares to the “reference” signal. Generally with system optimization, we have two main transfer functions: DSP Out compared to Console Out, and Reference Mic compared to Console Out. The first will show what the DSP is doing to the board mix, and the second will show how well the system is transmitting that mix in the space.

Anything “upstream” of the reference signal tap point will not show up in TF view because it’s part of the reference signal. For example feedback is invisible on a TF because it’s part of the signal leaving the console AND the signal coming into the reference mic. So my guess without more information is that your tap points and your patching aren’t aligned properly. If you take a feed out of the desk as your reference channel in Smaart, you don’t see the results of any EQ added at the console, for example, because it doesn’t happen between the two tap points of the transfer function measurement, and so doesn’t cause a difference between them.

It’s tempting to think of the TF magnitude display as being the absolute response of the system, but it’s not. It’s showing the CHANGE caused by the system. 

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