V1 sound quality

[Leslie Wand]

just returned from my wife's book launch - held in a museum in sydney uni.

a. beautifully lit cases and exhibits, hardly any other lighting. well, the cases were brilliant, people too dark, split the difference, ended up at 12db gain, a little noisy in the shadows, but pretty good otherwise. i have yet to find a client (not another pro) who will complain about 'noise' in a low lit shot. all due thanks must go (presumably) to all those reality tv shows shot with mini cams in dark cars / rooms that 'educated' their audience to the fact that night-time, low light situations usually end up grainy. first comments on this project are - what noise?

b. audio - just as piotr points out - the audio is adequate. i shot with a me80, manual and turned up to about 7. no added gain. got home, eq'd and fiddled a bit (not much), and i have perfectly acceptable speeches, background chatter, glasses breaking (not the cases thank goodness!), etc.,

i still hate the linking of ch 1 and 2 together - i would have preferred to have run ch 1 at auto, and 2 at my setting. i feelsafer that way....

but other than that - all this talk of low-light 'horrors', and useless audio, seems to be from people shooting black cats in dark rooms, and recording audio either next to a monitor stack, or from across the road from their subject.

leslie

[Christopher Lefchik]

Originally Posted by Douglas Spotted Eagle

My apologies to all, the FUD post had already been removed from public view (and forgotten).
The thread had been closed by one moderator and moved by another.
The edited version of the original thread may be found here

Hmm, unless I’m missing something that thread doesn’t have any test results. Also, it isn’t about the low end frequency response of the V1.

Originally Posted by Douglas Spotted Eagle

Christopher, if you're reading and accepting of that information, then the only test result that will likely satisfy you is one you take yourself.

If I owned a V1 I would be happy to test it and post the results.

Actually, the reason I’m so interested in this subject is because I’m considering purchasing a V1. It appears that it would be a good replacement/upgrade for my VX2000 in many respects. However, I like to research and consider big purchases and not take a blind leap. I’d really like to know what I’m getting before I drop 4k+ on a camera.

Originally Posted by Douglas Spotted Eagle

the V1u, given a flat tone, at a standard level, will reproduce that tone. Given the variables of a microphone, room tone, and whatever other variables may be introduced isn't a test, it's a guess.
Putting in an oscillator sweep produces fairly accurate reproduction up to about 16k and down to approx 80Hz. This is typical of compressed formats.

The RightMark test results I’ve seen of the V1's audio response were from a test conducted with the camera in DV mode. Thus, the audio was recorded as uncompressed PCM and there was no chance of MPEG audio compression altering the recorded signal. The signal was fed directly into the camera through the XLR jacks in line-in mode - no microphone was used. As such, microphone characteristics and room tone could not have colored the results.

The RightMark Frequency response measured under these conditions shows the V1's audio response beginning a steep dive around 600 Hz. It’s in a shallow decline before then, but 600 Hz is where the decline really begins to enter a steep curve.

I looked at some test results on RightMark’s site for audio equipment, and even an old multimedia (i.e., non-pro level) Creative SoundBlaster Live 5.1 sound card has a frequency response that is strikingly flatter than the results for the V1.

If you’ve posted test results that refute these, then my apologies as I missed them.

Originally Posted by Chris Hurd

Indeed, if there is a FUD post here on DV Info Net, then it needs to be withdrawn from public view. We're working hard to make this site a FUD-free zone, so if that sort of thing is happening here, it should be reported so it can be excised. Thanks in advance,

My apologies if it sounded as if I was interested in FUD. The reason I asked for the link to the thread Douglas Spotted Eagle mentioned was that he seemed to be saying it contained test results showing the true frequency response of the V1.

I want to make it clear: I’m not trying to be hard headed. I’m not interested in FUD. I’ve seen the test results and hard numbers on one side. If there are test results and hard numbers that contradict these then I would really appreciate seeing them.

[Christopher Lefchik]

Originally Posted by Piotr Wozniacki

Sorry I didn't respond earlier. No, sorry - I have no testing facility or time for it; it's my eyes and ears I always trust.

No problem, I understand. Thanks!

[Piotr Wozniacki]

Christopher, I understand perfectly your being anxious about an investment in a new camera that might not fulfill your expectations, but believe me - I'm the same; I spent a couple of months trying to make up my mind on which way to go - the Canon A1 (which I tested for 6 weeks) or the V1 (which I had for 2 weeks before the Canon, and returned because of the early 25p problems). Considering all pros and cons, I have chosen the V1 after all. As you can see in my sig, I also had a CCD-VX3 Hi8 camcorder before I entered the digital world. I can assure you the V1's audio is no worse than that of the other two. Yes, with the supplied mic it's a bit low - but still adequate; with a hotter mic it doesn't show any flaws in my opinion. The only thing lacking is the ability of a single mic feeding both channels with different levels throught single input (CH1) - but you can use an Y-cable to feed them separately as a work-around.

I have also seen the measurements showing a dramatic dive of response to the left of a threshold frequency as high as 1200 Hz; have no idea what was the purpose of the person publishing them because - as I said - I trust my own ears, and I could hear it easily should it actually be a V1's 'feature'.

When you analyze the graph I posted, please note I have also boosted the high frequencies - I did it to "lighten" the overall sound atmosphere of a live recording in a rather noisy venue (a church), with plenty of reverbs present. This might be the reason of my first impression that the other recording was reacher in basses, as it was absolutely flat. - when I have time, I might try to remove the high freq boost, adjust the loudness of the 2 recordings and only then compare them in the bass department again. I'll keep you posted.

[Bob Grant]

Can I respectfully suggest a little study of the science of acoustics?

Two matched microphones even a few inches apart recording into identical gear in a very 'live' environment such as a church can produce dramatically different results. The purists working in the field of live acoustic recording spend way more than the price of a V1 just on a microphone and then spend considerable time (and no small amount of experience) getting microphone placement correct. They do nothing to the recorded sound either apart from matrix decoding.

Spending money on a good let alone excellent mic and pluging it into a camera, any camera, is going to give variable results. Microphone performance can be affected by several factors, termination impedance and the quality of the phantom power. That's before the signal hits the camera. From then on it's amplified and fed through A->D converters built from commodity components. That's not dissing the camera manufacturers, they're doing good engineering, they know anyone who wants top shelf audio isn't going to record in camera anyway and the cost burden of decent let alone top shelf audio would more than double the retail price of the camera and you'd still be stuck with 16 bit PCM or mpeg-1 anyway.

For me the only thing missing on cameras audio sections is enough bottom end cutoff, I've more than once wished for a good roll off of 18dB/octave or more. Would have helped when untalented talent start banging on desks, kicking my mic stand or thumping my mic to see if it's on.

To compare what got recorded by a microphone placed 'somewhere', into a camera, to what was recorded by guys with lots of experience and gear who were focussed on only the audio is a pointless exercise. Spending some time learning from the people who made that 'other' recording would be a better way to go.

And if you're really serious about audio, spending some money on decent plugins wouldn't be such a bad move either. The plugs that ship with Vegas aren't entirely useless but they're certainly not stellar either. Of course if it's recorded right in the first place very, very little to nothing is the best plug of all.

[Piotr Wozniacki]

Very true, Bob :)

Let me stress though, that in my original post of this thread, my intention was not to compare apples to oranges, and criticize apples for not tasting like oranges do. On the contrary; as a follow-up to my previous post about the generally positive church recording experience, I wanted to confirm the sound recorded by V1 can at all be comparable to professionally recorded audio. Really not much was needed to make them sound identical...

[Piotr Wozniacki]

Originally Posted by Christopher Lefchik

Really, though, I don't understand such a big rolloff. Like you said, why can't it have a flat response as is the case with even cheap audio recorders? Is such a rolloff natural with any current audio DSPs? Or is this something that would have to be added purposefully? If so, why wouldn't it be switchable by the user on such a pro broadcast camera?

The inclusion of pro audio features such as XLR inputs would tend to suggest that the V1U should handle audio decently. As such, the inclusion of an unswitchable high-pass filter doesn't make sense to me.

Well, in the light that Bob has just shed on the subject (particularly his remarks on accidental, low frequency noises spoiling recordings), and taking into consideration the V1 is by design more suited for ENG run&gun type of work rather than recording musical performances - I'd tend to suspect the evident bass roll-off placed relatively high could be there on purpose...

[Bob Grant]

Fair enough,
I'm still a bit interested in this though, not so much from the V1 point of view but why the two recordings ended up so different. Of course you may never know if what they'd done to their recording had any bearing on their sound compared to yours. Just that you seem to be applying a aweful lot of Eq that could have side effects.

What I'm also thinking about is what kind of sound you're after, one that sounds good or one that's accurate.

Edit:

I just went and looked up the specs on the mic that you're using. I'm wondering if that has any bearing on what you're hearing. Certainly not the kind of mic I've had anyone recommend for your application. Typical mics are X-Y mics such as the Rode NT4 or (if you've got a wad of cash) the Soundfield mic.
In this kind of environment what the mic records is I think a bit more complex than you can judge just looking at response curves, they're measured in anechoic test rooms and a church is a vastly different place unless you're close micing.

[Piotr Wozniacki]

Originally Posted by Bob Grant

What I'm also thinking about is what kind of sound you're after, one that sounds good or one that's accurate.

Both:)
Seriously though (well, still not quite), the former takes precedence with me. Imagine guitar and violin in a venue like a church; which would prevail? The violin of course! Now, due to reverbs present, what do you do to quickly clean it up? Boosting trebles, right? OK - that's what I did; the result being even further domination of the violin over guitar.

Now, to complicate things even more (and make them interesting), imagine the guitarrist happens to be your brother-in-law. He says: hey, I canot hear myself loud enough; my instrument got dominated by the violin (and the violinist happens to be one of the most prominent Polish violin player)...

Then we get hold of the radio recording; what does my brother-in-law say? -Hey, this sounds a lot better to me, at least the guitar is audible! So what do you do to please him? Boost the basses! By as much as only possible before distorsion starts (hence 14 dB in the graph posted...).

On the other hand, the radio crew had of course two high quality mono mics, one of them directed lower towards the guitar, the other one - higher to where the violin sound emanated... They could have balanced the two channels very easily (no equalization was done, though, AFAIK).

So, this has been what, and why, I did to the original V1 audio. Just a short sample of the result: http://rapidshare.com/files/48330102/V1_in_church.wav

[Piotr Wozniacki]

Originally Posted by Bob Grant

I just went and looked up the specs on the mic that you're using. I'm wondering if that has any bearing on what you're hearing. Certainly not the kind of mic I've had anyone recommend for your application. Typical mics are X-Y mics such as the Rode NT4 or (if you've got a wad of cash) the Soundfield mic.
In this kind of environment what the mic records is I think a bit more complex than you can judge just looking at response curves, they're measured in anechoic test rooms and a church is a vastly different place unless you're close micing.

Absolutely Bob - the CS-50 mic by Edirol is just a general-purpose stereo shotgun. And yet, giving acceptable results even for music recordings.

[Bob Grant]

Well I've listened and looked. (and sorry Chris this is getting WAY off anything V1).

The recording is mono, or so close it doesn't matter. That's both by my ears and phase meters. That means we've lost the ability to localise the sound, the violin and the guitar are mixed together in the one place. In a stereo recording yes the violin might be a lot louder than the guitar but our ears and brains can separate them. Furthermore, with a stereo recording (or dual mono like the radio guys were doing) you have chance to adjust the balance.

Worse still, well for me at least, that recording has no sense of 'place'. The listener should be able to close their eyes and 'see' the church but all the cues are missing. But, not only is the acoustics missing that gives the sense of place (which is what would happen with close micing) but we've lost the the sound of THE guitar and THE violin, we're kind of left with A guitar and A violin.

Did you by any chance have your mic set to Focus instead of Wide?

A couple of tips:
1) Eq in this situation is a very blunt tool, I've found I can lift the guitar out of the mix a bit using a multiband compressor to get more attack on the guitar. Not a dramatic improvement but worthwhile.
2) In general when using Eq it's better to turn down what you don't want than to turn up what you do want, at least when you want drastic changes. This way you can avoid clipping.
3) Your project prefs might be wrong, the sample is 44.1K, not a big issue but best to avoid resampling, even when playing back on the timeline it's using up CPU cycles.

[Piotr Wozniacki]

Thanks Bob for your remarks, I really apreciate it.

Yes , I did use focus instead of wide in purpose - I couldn't get close enough to the 'stage', and wanted to eliminate as much reverb and surrounding noise as possible. Of course this is the reason it sounds almost monoaural, but let me note that complete separation of the two instruments would be wrong, as well. Nevertheless, at the next opportunity I'll try the wide setting.

Or, better still, use my new cables with all possible connectors/adapters to get a proper sound through the Line inputs:)

PS. Bob, can you recommend some reading on audio recording/postprocessing? You know - for technically capable, but not specializing in the field, guys like myself...

[Piotr Wozniacki]

Originally Posted by Bob Grant

I just went and looked up the specs on the mic that you're using. I'm wondering if that has any bearing on what you're hearing. Certainly not the kind of mic I've had anyone recommend for your application. Typical mics are X-Y mics such as the Rode NT4 or (if you've got a wad of cash) the Soundfield mic.
In this kind of environment what the mic records is I think a bit more complex than you can judge just looking at response curves, they're measured in anechoic test rooms and a church is a vastly different place unless you're close micing.

Bob, would the AT835ST be a better choice than the Edirol?

http://www.audio-technica.com/cms/wi...fa7/index.html

[Bob Grant]

Some good info here:
http://www.xowave.com/doc/recording/mic-pair.shtml
and perhaps more than you'd want to know here:
http://www9.dw-world.de/rtc/infotheq..._recording.pdf

The AT mic you're looking at has the same problem as the one you've got, well not so much the mic as what you think it can do for you. Take a look at the polar plot in Narrow. Nothing, it's a mono hypercardiod. No doubt a very good one but that's not the way to get a good stereo image.
I've just finished editing a short brass and organ piece for a client, didn't shoot it myself but the client / conductor /composer tells me they used his AT825 plugged into the camera, sounds pretty good, it sounds like you're in the cathedral. The Rode NT4 is also a good mic for this kind of recording, the AT825 is a little light at the bottom end for big pipe organs, we might get a DPA 'reference' mic that goes down to 10Hz for this as well.

It's a bit of a problem venue as it's in the middle of the Sydney CBD and the organ is half way up a side wall, that's where they also had the brass players. The client told be today he took a lot of trouble walking around the venue listening for the best place for the mic while the musicians warmed up and rehearsed. Now, it was pouring rain when they recorded this. Sure you can hear the rain and the outside traffic noise and the odd clang and bang, no doubt if there was an audience there'd be the odd cough and splutter from them in the mix too. But it's a live recording, the listener will cope with this, they know it's not a studio recording, that's what the video bit is for, to tell them where they are and the sound should enhance that experience. For this kind of thing the sound is the show, the video is just there really so they're not looking at a blank TV.

Now I know you've got an issue with putting a mic where it should go but a bit of lateral thinking might solve your problems. Get a cathedral pole, it's a very tall stand with a long boom. For the event in question it can go behind the alter with a few shot bags on the base. The mic goes in front of and and above the performers. Record into a standalone recorder, leave enough headroom so clipping is impossible and just leave it running while you worry about the video. Or else get a long 5 pin XLR cable and lots of gaffer tape and run a lead back to your camera.

Anyways, hope this gives you some ideas. This isn't a simple thing to master and I'm no expert. One thing I learned long ago though was for acoustic recordings don't think about frequency, think about wavelength. You start to see the problems is a different light.

[Piotr Wozniacki]

Thanks again Bob for the invaluable hints. I admit I mainly treated the event as a test for the video side (I knew it would be not very bright inside the church); I didn't bother too much about the audio because I knew in advance it would be recorded by the radio guys, so I'd bee getting a CD from them, anway.

For the next time though, I'll get better prepared.