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-   Sony HVR-V1 / HDR-FX7 (https://www.dvinfo.net/forum/sony-hvr-v1-hdr-fx7/)
-   -   wind noise reduction (https://www.dvinfo.net/forum/sony-hvr-v1-hdr-fx7/90935-wind-noise-reduction.html)

Piotr Wozniacki April 7th, 2007 05:17 AM

wind noise reduction
 
With the V1's stock mic, connected to CH1 and recording to CH1+CH2, is it necessarry to switch both channels' wind noise reduction, or is that of CH1 enough?

Piotr Wozniacki May 8th, 2007 02:11 PM

Nobody answered, so I'm kicking this up - even though but my experiments in the meantime proved both channels should probably have the wind noise filter on (or off, for that matter).

I have another question on this: is "Wind noise reduction" a simple high-pass filter, merely cutting the level of everything below a certain freq value (like 80 Hz rollover on microphones), or something more sophisticated? Because if all it does is cut low frequencies, I don't see a point in using it at all! I believe it's better to record full bandwidth audio, and only filter out those wind "knocks" in post.

I'm looking forward to a more experienced person's opinion. TIA!

Serena Steuart May 13th, 2007 11:55 PM

wind noise
 
IMO wind noise cannot be removed in post. Various methods are available for reducing it in post, at cost of effort and audio quality. Unless recording in a hurricane, it's easy enough to protect the mic (much preferably a separate mic). I don't like electronic so-called wind filters, but they can reduce problems in quite light winds (guess they're better than nothing).

Vaughan Wood May 14th, 2007 01:49 AM

I agree with Serena.

Although a lot of audible wind noise is in the bass end, it is usually visible in the whole audio spectrum, and is usually impossible to fix in post if it is affecting speech etc.

Cheers Vaughan

(also from Melbourne)

Leslie Wand May 14th, 2007 03:46 AM

and wouldn't it be a joy if you could switch nr on one channel only, and leave it off on the other.

i really, really, really, don't understand why sony fixed something that wasn't in the least bit broken - ie. one mic feeding ch 1 and 2, seperately, just like the 170 / 150.

leslie

not in melbourne, but in the upper hunter, nsw

Piotr Wozniacki May 14th, 2007 04:08 AM

Quote:

Originally Posted by Piotr Wozniacki (Post 655657)
With the V1's stock mic, connected to CH1 and recording to CH1+CH2, is it necessarry to switch both channels' wind noise reduction?

Leslie, do you mean that the answer to my original question is "NO"?

Bob Grant May 14th, 2007 05:05 AM

Quote:

Originally Posted by Piotr Wozniacki (Post 675026)
I have another question on this: is "Wind noise reduction" a simple high-pass filter, merely cutting the level of everything below a certain freq value (like 80 Hz rollover on microphones), or something more sophisticated? Because if all it does is cut low frequencies, I don't see a point in using it at all! I believe it's better to record full bandwidth audio, and only filter out those wind "knocks" in post.

I'm looking forward to a more experienced person's opinion. TIA!

Don't know if I'm a more experienced person but I'll give it a shot.
I'd be pretty certain that the 'wind filter' isn't anymore than a simple high pass filter as you've suggested however such a thing isn't entirely useless. There's a plus to not recording part of the spectrum you intend to remove in post anyway. Doing this gives you more headroom for the wanted part of the spectrum. Also if you've got AGC on then the AGC is likely to be adjusting to the level of the wind noise rather than the wanted signal.

Keep in mind that wind of itself makes no noise, it's the turbulance created by objects in it's path that create sound.

Piotr Wozniacki May 14th, 2007 05:30 AM

Quote:

Originally Posted by Bob Grant (Post 678778)
There's a plus to not recording part of the spectrum you intend to remove in post anyway. Doing this gives you more headroom for the wanted part of the spectrum. Also if you've got AGC on then the AGC is likely to be adjusting to the level of the wind noise rather than the wanted signal.

Good point, Bob. However, if the "wanted part of the spectrum" happens to be below the filter cut-off limit, I'm gonna lose it forever! And this is my main objection, unless the wind noise reduction is something more intelligent:-)

Leslie Wand May 14th, 2007 06:29 AM

Quote:

Originally Posted by Piotr Wozniacki (Post 678757)
Leslie, do you mean that the answer to my original question is "NO"?

i wish i knew! it would appear that there is no separation on one mic input, at least not with volume control, i would therefore presume (i hope i'm proved wrong!) that nr if on on one channel would be applied to both.

i'm not really in a position to test this right now, but i might have a go tomorrow and see if i can discern any difference recording white noise. if anyone has a better idea, please tell me.

leslie

Douglas Spotted Eagle May 14th, 2007 06:58 AM

I'm not clear on what you're wanting. You can feed channel 1 or 2 separately or jointly.
Plug one mic only into channel 1, it can feed channel 1 only, or channel 1/2 simultaneously.
Look to the 1/2 switch on the front of the audio block.

Piotr Wozniacki May 14th, 2007 10:04 AM

Douglas, please see my first post in this thread, in connection with this one:
http://www.dvinfo.net/conf/showthread.php?t=93180

Bob Grant May 14th, 2007 04:13 PM

On the V1 as far as I know the AGC is either on or off for both channels. Same goes for wind filter. Yes the 150/170 let you control AGC independantly on both channels but not the 'wind' filter.

I kind of have to wonder why all the angst over the audio section of any HDV camera. From my experience HDV's mpeg1 audio doesn't justify Sony or anyone else spending a bundle on the audio section of the cameras.

One could buy a good two channel mic pre and feed the output into the V1/Z1 etc at line level. Personally I'd be feeding it into a separate PCM recorder and using the HDV audio as a guide track.

Leslie Wand May 14th, 2007 05:46 PM

hi dse,

feeding a single mic into channel one, and selecting it's output to both ch 1 and 2 on the v1 gives NO separate control AT ALL, unlike the 150/170, where ch 1 could be agc, and ch 2 manual.

bob,

foggy down there today?

i wouldn't exactly call it angst - more annoyance. i haven't had a great deal of experience with mpeg1 audio as yet, but i'll make the following observations:

a. there are many situations where i'll be using an on-board mic (be it sony's or my senn) to be simply capturing ambient or atmosphere. quality will not be of that great importance, but volume will. on my 170 i could simply set ch 1 to auto, ch 2 to manual and work out the best 'guess' level for it. this set-up has proved itself (in my eyes anyway) invaluable for many situations, and has given me usable audio in situations where one or other channel couldn't cope.

b. i'm not asking sony to spend anything on their audio block - just put it back to how it bloody well was!

c. i couldn't agree more that if sound is important, then you'd want the best options available. however, in the real world (well, mine anyway), i'm a one man band most of the time - so running peripherals is generally a no go (especially since i'd have to hire them from you, and you're 300km away!).

d. ditto, running two mics - other than devising/buying some on camera mount for a second shotgun - only adds weight and makes handling the camera more cumbersome when shooting hand held.

perhaps all this stems back from too many years in the business and working with a 'simple' betasp 400 rig ;-}

i have yet to really come to terms with all the cameras built in cc stuff as well - i was always taught to shoot the best possible pictures at the optimum exposure levels, ANYTHING else, such as colour correction, could be done in post, and that was in analogue, digital makes this even more practical!

anyway, i've ranted enough about the stupidity of sony claiming 'separation' of input from channel one when fed to ch 1 AND 2....

have a gud un,

leslie

Steve Mullen May 14th, 2007 07:18 PM

[QUOTE=Leslie Wand;679222i wouldn't exactly call it angst - more annoyance. i haven't had a great deal of experience with mpeg1 audio as yet, but i'll make the following observations:

a. there are many situations where i'll be using an on-board mic (be it sony's or my senn) to be simply capturing ambient or atmosphere. quality will not be of that great importance, but volume will.

c. i couldn't agree more that if sound is important, then you'd want the best options available. however, in the real world (well, mine anyway), i'm a one man band most of the time - so running peripherals is generally a no go (especially since i'd have to hire them from you, and you're 300km away!).

leslie[/QUOTE]

Despite the many early comments about how MP2 audio was going to be unusable -- most from those who had yet to use it -- the number of posts over many years about ACTUAL poor quality sound is small. Those shooting film with "separate system" continued to do so. Those who didn't -- didn't switch for exactly the reasons you stated so well.

In the REAL WORLD -- like yours -- it has become a non-issue. MP2 quality is higher than was ever available before PCM audio!

In fact, if you were to be looking at other places for information, the big budget alpha males would you tell you that HDV itself was unusable. Of course, these very same individuals claimed DV was unusable.

Don't be pushed into spending more because someone scares you into worrying about something. Find-out for yourself.

Douglas Spotted Eagle May 14th, 2007 08:10 PM

Leslie, I was unawares that you wanted AGC, I don't use AGC, so didn't even consider that in my response. Apologies for missing the finer point.
Bob's got the best suggestion, IMO; if you want *good* dynamic control, then use external. PITA, but necessary if you can't control the source.
Outside of AGC, the inputs are discreet, and controllable. Many times, I feed one mic/two levels with this system.


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