More sound advice

THIS morning we posted some text copied from an online course that director Martyn Moore is studying. He helped a fellow student with some specific technical questions that the course didn't cover. Already we've had some questions sent in to Martyn on other aspects of film-making. Feel free to comment on these posts or send in your own via the contact page.

Martyn would like to help other film-makers in the way he got help when he was starting out. Send in your film-making questions and he will answer as many of them as he can. He might not be able to answer all of them and not everything will be published on the blog.

In the meantime, here's another conversation from the online course.

Martyn Moore
Email me, Tony: [email protected] or if you have specific questions that will benefit other students, what do you want to know?
 
Tony Franks
Thank you Martyn, that's kind of you to offer to help.
Basically for straightforward interview situations (single subject) with an iPhone or compact camera, what are the pros and cons of using a) external mics and b) external recorders? I don't own either but I should make the investment...
(I've posted this on the forum as maybe your advice is useful for other students).
Thanks again! Tony
 
Martyn Moore
Phones and small cameras have to compromise on sound. The lens and recording components fit well into their bodies but a microphone can't work well as part of the camera.
The aim in an interview is to get as much of the spoken sound as possible and as little of the background, or ambient, sound as you can. The best way to do this is by getting the microphone as close as possible to the mouth of the speaker.
We do this by using a tie clip mic, sometimes called a lavalier (lav) mic or a shotgun mic pointed straight at the speaker. Microphones have different types of 'capture' fields, or shapes. Uni-directional capture a thin beam of sound from a limited direction; omni-directional mics capture sound from all around; cartoid mics capture a heart-shaped field from around the front of the mic's head. Google the words for diagrams.
So I have lav mics that are uni- and omni-directional and I choose the one that suits the situation. If I only had one, I'd choose uni-directional. If your camera or phone has a mic input socket, simply connecting an external mic to that will make a massive difference.
Most mics require a small power supply from the input socket of the device, so check what type your device needs and buy the right one. Devices that don't provide mic power might need a mic with on-board batteries. You will need to check out the options.
I am constantly on the verge of buying a new separate sound recorder but haven't taken the plunge yet. All my cameras have professional mic inputs but I think an audio recorder will be useful. I keep looking at this TASCAM: http://tascam.com/product/dr-40/ because it has all the right input sockets and can be used as a 'sound only' interview recorder. Alternatively, there's this: http://tascam.com/product/dr-60dmkii/
The ultimate combination is a sound recorder with external mics. Everything I wrote about lavs and directional mics applies here too.
So far we've only talked about hard wired mics but there is also the world of radio mics to consider. A radio mic set usually consists of a lav mic, a transmitter unit, a receiver unit and a cable to suit your camera/recorder input. The transmitter/receiver should have lots of channel/frequency adjustment to prevent interference from other systems and local taxis.
 
Martyn Moore
I currently use this set-up: http://en-uk.sennheiser.com/wireless-clip-on-lavalier-microphone-set-presentation-ew-100-eng-g3 but expect to replace it with something like this: http://www.sony.co.uk/pro/product/broadcast-products-professional-audio-portable-microphone-packages-uwpd/uwp-d11/overview/
On a recent trip to America I also bought this but hesitate to recommend it until I've used it more: http://www.bhphotovideo.com/c/product/1007208-REG/polsen_ulw_16_pl4_uhf_eng_wireless_system_16.html
I hope this is useful. That's a lot of typing. I need to lie down...
 
Tony Franks
Martyn- that's a wealth of info and advice: thanks so much. I've got my eye on a Tascam...
Thank you again, on behalf of myself, and the group.
 
Martyn Moore
The Tascam looks great but there are lots of cheaper options. A £40 Olympus recorder with a £20 lav mic will be miles better than your phone/camera's built-in mic.
If you use a separate sound recorder, remember to clap your hands on camera and on mic at the start of each clip. This makes it much easier to sync the tracks in the edit.