EX3 Audio Question

[Jay Gladwell]

As I've said before, the manual--Operating Instructions--for the EX3 leaves a great deal to be desired.

For instance, under the AUDIO SET Menu, can some tell me where I can find more useful information on the "Trim" and the "Wind Filter" settings?

Thanks!

[Bob Jackson]

On the EX1 :The trim audio functions are available(accessible) only on external mics.

[Brian Cassar]

I agree with Jay.

Can someone please explain in more detail what Trim is all about? What does it actually do and what does one achieve when the settings are altered?

[Jay Gladwell]

Originally Posted by Bob Jackson

On the EX1 :The trim audio functions are available(accessible) only on external mics.

Thanks, Bob, I was able to figure out that much on my own. I've also figured out that the higher (lower since it's a minus?) the number is the louder the sound becomes.

I want to know:

1. What it is.
2. How it works.
3. It's strengths & weaknesses
4. How best to apply it.

[Chris Hurd]

Those are great questions, Jay, and they're right up our alley. I'm looking forward to watching this thread develop into some solid, usable information about EX series audio.

[Ted OMalley]

I'm very interested in this as well. I don't want to have to fall back on auto level control, but I feel like I'm working a little blind going manual.

I use both Sennheiser wireless going line in and an NCG-1 Rode using Mic+48. How will trim affect these?

The level controls are fairly straightforward - my understanding is that I need to prevent clipping and peak somewhere around -12dB for normal audio The occasional loud noise should never exceed 0 or I've lost it. But this doesn't help me any when it comes to the trims.

Also, in the same menu, I've heard people praise the wind filter. More feedback on this would be nice, too. Should it only be used outdoors? Should it never be used and should this be handled only by your 'softie' or in post if necessary?

[Jay Gladwell]

Ted, the Wind Filters only work with the internal/onboard mic. It has no effect on external mics.

So far, I've figured out that the larger the minus numbers are in the Trim setting the more volume you get for the external mics. Currently, I have both channels set at -54dBu. This seems to work with my Rode NTG-3.

Not being a high-tech audio person, I really anxious to figure this out before I create a problem.

[Piotr Wozniacki]

Originally Posted by Jay Gladwell

Ted, the Wind Filters only work with the internal/onboard mic. It has no effect on external mics.

I don't have my EX1 with me (gone for an overhaul), but I don't think that's right - please correct me.

Regarding the trimming: due to the internal limiter (yes - there IS one) weirdness, it's always safe to have it quite aggressive (like around -30dB), and the gain at the neutral position (i.e. 5). Should a sudden loud audio event occur, this will prevent from anti-clipping compression which can sound really ugly.

The overall quality of the EX audio is good enough to increase the (perhaps too low) overall sound level in post, without introducing hiss or other noise.

[Jay Gladwell]

Originally Posted by Piotr Wozniacki

I don't have my EX1 with me (gone for an overhaul), but I don't think that's right - please correct me.

Piotr, according to Doug Jensen's "Mastering the Sony PMW-EX3," the Wind Filter works only with the internal mic. Take that with a grain of salt.

[Alister Chapman]

The trim function adjusts the sensitivity of the input. Different microphones and audio devices output at different levels. For example a radio mic receiver that outputs at mic level will probably be "louder" than a dynamic type microphone. The trim adjustment allows you to compensate for these varying levels. -67dBu is more sensitive than -11dBu.

I set the trim by first selecting manual audio level control. Turn the level control knob to the mid position (5). Talk in to the microphone at the level you expect for the job and look at the audio levels. You want to have the levels in the "comfort zone", ie mid range, not too high not too low. Certainly not going past 3/4 of the way up the scale, hopefully peaking just a little past half way. Use the input trim if your levels are not in the comfort zone.

If you make the microphone too sensitive (say -67dBu) and then have to wind the level control down to get a decent level your recordings may be noisier than they would be with a less sensitive setting, also it is difficult to make small adjustments to the recorded level if you have the knob turn all the way down. Also loud noises may overload the input and cause distortion.
If you don't make the input sensitive enough then you may struggle to record good audio levels. When you go to edit your material you then might have to use a lot of gain in post production to bring the audio up to the correct level. This will introduce noise and in effect reduce the dynamic range.

If anything it is better to be a little on the low side when it comes to levels. Too high and you will get distortion, unexpected loud sounds may clip, whereas if you are a little low a small amount of tweaking in post shouldn't hurt too much.

For my condenser type gun mics I am normally somewhere around -47dBu.

The wind filter is a simple low cut filter that cuts off some of the low frequency rumble caused by wind blowing across the mic. It works on both the internal and external mic.

The EX cameras have an aggressive audio compressor that starts to kick in before the levels get in to the red. The limiter has a fast attack and delay. If your audio levels are set too high you can hear the audio pumping. Often most evident if you turn the volume up and listen to the background noise which you will hear going up and down in volume. To avoid this keep your audio peaks to around the 3/4 mark and no more.

This is how I do it and it works for me, others may have a different view.

[Jay Gladwell]

Thank you, Alister, that was a big help! You've provided enough information that I can begin to see what the Trim is and how it works.

Any further insights by anyone else would be greatly appreciated.

[Ted OMalley]

Alister - Thanks so much! I've finally had my EX3 audio primer!

[Brian Cassar]

Thanks Alister from me as well.

However I would like to ask whether the "trim" function works in the AGC mode for audio. My work is primarily run gun type and there is no time for manual control of audio. If the trim level is altered in auto level audio what would be the effect?

[Daniel Epstein]

I think Alister has given some good advice. My reading of the trim settings are a little more technical. Most mic level signals should correspond to a -60db to -40db range. Consumer line levels (usually RCA) range from -20DB to -10DB. Professional Line Level ranges from 0DB to +4DB. The trim should be used to try and match the mic output to the camera input so you get a proper audio recording without distortion from impedance mismatches. It is very possible to set the trim characteristics incorrectly and have distortion added to the signal recorded by the camera even if using auto level record settings. Some Radio mics have adjustable outputs and this should be considered when setting up the inputs for the EX1. Many mixers have adjustable outputs (ie Sound Devices) but many don't so tests should be done to see that the inputs can handle the level coming from the external device. Defnitely not as easy as just a good old Mic Line switch which was usually mic at -60 and line at +4

[Jay Gladwell]

Thanks for your input, Daniel. I have a couple of questions:

Originally Posted by Daniel Epstein

The trim should be used to try and match the mic output to the camera input so you get a proper audio recording without distortion from impedance mismatches.

How does one match the trim with the mic's output/impedance? For instance, my Rode NTG-3 has an output impedance of 25Ω.

Originally Posted by Daniel Epstein

It is very possible to set the trim characteristics incorrectly and have distortion added to the signal recorded by the camera even if using auto level record settings.

How does one avoid this?