[Richard Crowley]

Tiny electret condenser microphone capsules or even smaller MEMS (micro-electro-mechanical systems) mics are quite plentiful and inexpensive. And they are remarkably accurate for their size and cost.

It is true that we normally try to minimize ambient sound when we are recording speech/dialog. But placement of one of these tiny mic capsules on a headband with the mic positioned at the back of the head would “optimize” the ambient sound pickup.

Some issues to address would include:

1) Minimizing wind noise with a foam gag or even a furry cover. That is what we use when recording outdoors to virtually eliminate wind nose. That is the wind noise that directly impinges on the diaphram of the mic. It would still properly pick up other wind noises like rustling leaves, etc. If the mic were positioned at the back of the head it would also reduce the wind noise from jogging cycling, etc. where the subject is moving through the outdoors.

2) Separating deliberate subject noises (specifically speech) from the ambient sound (or sound-level). Maybe you could convince your subjects to faithfully use a mute button when they are speaking, but that seems unlikely. Or maybe you could statistically throw out the outlying data points as uncorrelated anomalies.

3) Recording the data. Do you want to actually record the sounds, or do you just want to record the SPL (sound pressure level)? Depending on your resources, you could devise a relatively inexpensive gadget perhaps the size of an Altoids tin that would record average SPL every 10 seconds with a time-stamp. That could be done with a tiny Arduino microcontroller which is $5 and the size of a postage-stamp. Plus another $10-15 worth of circuit for the timestamp and audio level conversion. There are plans for time-of-day circuits (using RealTimeClock RTC chips) and for sound level measurement (both hardware and software) out there on the internet.

Here are just a few items of interest. There are hundreds more.
https://www.sparkfun.com/products/8635
https://www.sparkfun.com/products/10028
https://www.adafruit.com/products/1713
https://learn.adafruit.com/adafruit-microphone-amplifier-breakout/measuring-sound-levels

[Richard Crowley]

Sorry, the only things I found with numbers like that are keyboards and parts for motorcycles. The details you need are what kinds of inputs and outputs the gear has so that you know what your options are for connecting to it.

[Richard Crowley]

What “hand mic”? What “speaker”?
Does the speaker have an audio output connector? You could tap into the announce audio there.
Is it a conventional microphone with an XLR cable? You could use a “mic splitter” to split the mic audio. So that it goes to both the speaker and to your recorder/camera.

There are many possible solutions, but they depend on the exact description of the announcer’s microphone and speaker.

[Richard Crowley]

If having both XLR and USB output is that important to you, then your choices are very narrow.

OTOH, inserting a simple XLR to USB “adapter” for computer use allows you to select from ALL of the various kinds of microphones.

“On-location interviews” covers a rather broad range of situations. You probably have a narrower definition in mind, but we don’t know what you are planning. A rather bulky dynamic cardioid microphone like that is probably OK for some situations, but probably not ideal for others.

[Richard Crowley]

No. There is no phantom power connection between the mixer output and the microphone inputs. Phantom power must be injected right at the mic input, and there is lots of circuits between the mic inputs and the final output.

Furthermore, applying phantom power to something like a mixer output is NOT recommended because the phantom power could damage the output from the mixer.

[Richard Crowley]

Simply, no, these are all quite independent factors.

The FORM-FACTOR of a microphone (clip-on “lav”, or hand-held, or stand-mount, or boom-hung, etc. has almost nothing to do with any other factor.

The DIRECTIONALITY of a microphone is also quite independent. Whether omni-directional, semi-cardioid, cardioid, hyper-cardioid, or “shotgun”(line-gradient or interference-tube).

And the TYPE of microphone is also quite independent, whether dynamic, ribbon, electret condenser, or traditional condenser.

To be sure, there are some practical limitations, you won’t find hyper-cardioid or shotgun clip-on lavs simply because their form-factor is not physically big enough to make them that directional at lower frequencies. And you probably won’t find dynamic or ribbon shotguns, either just because of requirements for the genre like size and sensitivity, etc.

[Richard Crowley]

Well, it depends on what your (or your customer’s) expectation of quality is. It could be considerably improved by:
1) Recording in a larger or less reverberant room. The near reflections sound like it was recorded in the loo (is that what you call it in the UK?)
2) Use a narrator with better breath control. He eats some of the words and it sounds like he is sitting down.

[Richard Crowley]

No there is no such animal. It is easy enough to convert audio into a USB data stream using cheap ICs. But there is no cheap solution for the other direction because there is virtually zero market for such a thing. They sell a million audio->USB chips for every 2 people who want the other direction. You are squarely on the wrong side of the law of supply and demand.

[Richard Crowley]

Unless you are going to do all of your playbacks on YOUR laptop with YOUR configuration, the verb “verify” doesn’t really mean anything, does it?

Did the festival warn entrants that if they submitted 5.1, it would be down-converted to stereo without their participation?

Sounds like a good reason to submit only stereo to film festivals. Where the filmmaker can control what the stereo mix-down sounds like.

[Richard Crowley]

Alas, that is the major side-effect of that kind of filtering.
One suggestion frequently heard is to apply the noise-reduction process in a series of less intense settings rather than all in a single pass.

Of course, reducing or eliminating noise during recording is always better than any kind of post-production processing. And you have demonstrated exactly why that is the case.