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Phil Allison[_4_] Phil Allison[_4_] is offline
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Default Shure SM7b Question

Sean B wrote:



I'm wondering if I'm reading this schematic correctly:

https://pubs.shure.com/view/guide/SM7B/en-US.pdf

(Wiring diagram is near the bottom of the document)

So the bass roll-off and presence-boost circuits are connected in
parallel with the voice coil?



** That is the best way to *predictably alter* the output of the mic with little regard to varying pre-amp loads.

The 260mH inductor bypasses part of the mic's low frequency current, while the "presence" series tuned circuit does the same for a band around 3.3 kHz.

The presence circuit is used in the "flat" condition and is switched out for boost.

FYI 260mH = 81 ohms at 50Hz.


..... Phil