What is Minimum Terminating Impedance?

[n_pontius]

Hi everyone,

I'm trying to understand what minimum terminating impedance is. I found the following definition:

What is "Minimum Terminating Impedance"?

...but I still don't understand exactly what it is and what it means for a microphone. I'm looking at a couple of shotgun microphones for filming and I want to know what the difference is between two similar mics (links below) that have different minimum terminating impedance ratings:

Sennheiser MKH 416-P48U3 - Short Gun Microphone - for Broadcast, Film, Radio and Television

Sennheiser MKH 8060 - Short Gun Condenser Microphone - for Films and Documentaries

Thanks for your help!

 

[bouldersoundguy]

Don't worry too much about it. Most mic preamps will have more than enough impedance to accommodate most mics. You're more likely to have a problem with piezo pickups, and then only if the instrument doesn't have its own preamp.

 

[rob aylestone]

I'd agree to not worry too much. In practice it's something that happens when any amplifier drives a load. If the terminating impedance is too low, then the preamp in the mic can fail to have the 'oomph' to fully drive it, and the output goes down. Most devices for the past twenty years or so now have had sensible input impedance, so it doesn't seem to be much of an issue any longer. It occasionally causes trouble with passive splits used on stage, where having to drive two mixers in parallel does load the mics too much. Transformer splits and solid stage ones are fine, but there are a lot of systems using simple y splits.

 

[n_pontius]

Thanks guys, your feedback has helped. I understand now how important a good preamp is