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Posted by Mark & Mary Ann Weiss on 07/02/07 00:04
"richard" <nomail@butterfly.net> wrote in message
news:aFMhi.1652$4A1.1464@news-server.bigpond.net.au...
> In article <7_Cfi.319661$NO1.815@fe05.news.easynews.com>,
> mweissX294@earthlink.net opined thusly:
> >
> >[snip stuff about LF rolloff on V1]
>
> It's probably a silly question, but are you sure you have the noise filter
> turned off? It's there to get rid of LF wind noise, as far as I can tell.
As
> a design engineer with some experience I can't conceive of any technical
> design tradeoffs which would limit the LF response. I agree with you, it
> should be flat to 5Hz. Any preamp can do that - it's the top end that
> sometimes stretches the designer and the components.
There are two noise filters on the V1U:
Mic noise filter
Wind Noise filter
I discovered that when measuring the LINE input response, neither of these
filters affect the response. The DO affect the response in MIC mode however,
and what they do is simply move the rollover from 1222Hz to some point even
higher in frequency.
The problem is that Sony has another non-defeatable filter in the audio
chain that affects mic and line input response. It cannot be defeated with
any of the menu choices. That third filter MAY be a DSP algorithm, and if it
is, Sony can fix the problem with a firmware update.
You're the first person, out of dozens who've responded to my posts about
this issue, who actually understands the technical aspects of this, such
that the absurdness of this "bell curve" frequency response on the V1U is as
obvious to you as it is to me. Unfortunately, we seem to be in rare company.
Nobody else gives a darn about this. I do. I am the one who trecked all
around NYC Saturday, having to fight with this kludge I made with the camera
and a Zoom H4 perched atop it via a hot shoe adapter (it resembled a space
station with a shuttle docked to it). The act of inserting and removing the
whole kit and kaboodle from a duffle bag as the occasion called for, was a
delicate and slow task, thanks to the extra audio baggage. Had the camera
had good audio, all I would have needed was a good stereo mic, plugged into
it.
> However I have another issue with the V1's sound. I have 6 of these
cameras
> which have probably been used a total of 100 times in the past 6 months.
On 2
> occasions the audio has gone unstable, resulting on first one channel
dropping
> out, then the other. This happened last week and I went about swapping
mics
> and cables to work out why one channel had disappeared. Then the other
channel
> went to high level white noise. I power cycled the camera and the white
noise
> went but one channel was still missing. I plugged my mics into one of the
> other cameras and got on with the shoot, and quarantined the suspect
camera.
> However it hasn't played up since. Anyone else experienced this? I
suspect
> it was a HF instability brough on by hot patching mics, indicating an
> inherently unstable design.
What I am realizing is that these modern cameras are, at their foundation,
digital computers. And we all know how 'reliable' computers are. However, I
have not encountered any reliability problems with my two V1Us. Their
performance has been consistent. I only use their audio for synch reference,
but I can see from the editor timeline that it is not missing of dropping
out anywhere during a shoot. And if you are not observing this problem on
the other 5 cameras, then if I were in your situation, I would send that
camera in for service, with a detailed description of the problem. It sounds
like there might be a bad solder joint somewhere that is affecting the
digital signal path.
Best Regards,
Mark A. Weiss, P.E.
www.mwcomms.com
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