is this level of noise okay? - sound test attached

M

mduron

New member
View attachment sound test.zip

Hi. I'm rather green and testing my gear for a pilot news satire show, which I'm hoping to start shooting next week on spec.

I'd be grateful if someone could please let me know if the level of noise on the attached sound test is okay, normal, acceptable, or, not?

My setup is as follows:
- Camera: AG-AF102EN - camera input: line 1, Audio Level - Channel 1: just a little to the left of center
- Mixer: an old second hand Shure FP33 - mixer input: mic, mixer output: line, master dial=0, left dial~2.25 [I think I calibrated the master dial correctly to zero].
- Microphone: Sanken CS-3e (new)

When I plugged the mic directly into the camera the noise level sounded very much the same as the attached sound test using the mixer.

I'd appreciate any comments or advice anyone can provide.

Many thanks,
Michael
 
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With a bit of luck, jmarkham (Jeff) will advise you on this.

He helped me enormously with a similar noobie audio recording issue. (Piano piece)

Jeffs got the good audio skills and knowledge.
 
Is it possible you could post a AIF or WAV file? The MP3 in your .zip file is at a sample rate of 22050 / 16bit.

If you would be so kind, it would be best to get a PCM format at 48kHz/16bit.

Thanks
jeff
 
Hey Michael,
Did you calibrate to the AF100 using the 1kHz test tone from the FP33?
This may be important for you because I notice your signal level from the AF100
is at peak -25db at 350Hz (which is likely the resonate tone of your voice).
To be honest, I don't record audio to the AF100 except for sync purposes.
I find the noise floor unacceptable and use external recorders fronted by
PSC or SoundDevices mixers.
If you must use the AF100, make sure you're recording with the audio set to LPCM
format .. and try to overcome the noise floor of the AF100 by hitting it with a stronger
line level from your FP33 (which is an *excellent* pre/mixer no matter how
old it is). The 1k test-tone will tell you the loudest possible signal level that will come
from the FP33 (so you don't clip). That will set your master level on the FP33.
I think you'll likely dial your level on the AF100 down from center a bit. Then, you
can use the mic gain on the FP33 to set the gain so that you can get between -12 and
-6 on the AF100. With those levels, you can manage the approx. -60db to -72db of
the AF100's line level noise. Mic level is much worse.
That said, I could work with your signal level .. I would just put a noise gate in around
-48db to knock out the AF100's noise floor.
So .. given that you've got a great sound chain ahead of the AF100, hit the AF100 with a
bit of a stronger signal to get that signal above the noise floor. You need to be mindful of
clipping the signal at the FP33 ... but the meters will tell you that.
But, if you want a pristine sound path, I recommend an external recorder (we like the Tascam HD2).
We still record to the AF100 for sync / redundancy.

Hope that helps..
jeff
PS: here's the FFT on your signal .. I think you can hit the AF100 with a stronger
signal than -25db and get quite a bit above the noise floor.
sound_test_PAZ.png



PPS: For those of you shooting for your post production staff, in every location that you go to, please
record at least 10seconds of the ambient sound at that location. And announce it
with "room tone" ... then go for ten seconds and say "cut". It's a huge help for us audio types.
Every time you move the mic / boom placements .. do it again....
 
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Hi, Jeff.

Firstly, thanks very much for all your kind remarks and analysis - much appreciated.

For the sample recording that I uploaded with my inital posting, I tried to calibrate the Shure FP33 mixer by turning on the 1kHz switch, then turning the master dial so that both the FP33's meter readings were on zero. I then turned the mic gain dial until the volume meter (displayed on the AF102 LCD screen) was peaking at around -20db, which I thought was the level required by TV broadcasters.

Could you please clarify two points?

Firstly, should I be increasing the mic gain dial on the Shure FP33 mixer to increase the levels on the AF102 db meter (on its LCD screen) so they peak at between -12db and -6db?

Secondly, should I set the AF102 Audio Level dial to one dot left of center, or where? [I'm confused as to whether I should set AF102 Audio Level dial in the center and then adjust the mixer mic gain dial, or, whether I should play around with the both the mixer mic gain dial and AF102 Audio Level dial to get the lowest amount of noise?]

If you could please clarify these two points or add anything else I'd be most grateful.

Many thanks and regards,
Michael
 
Hi, Jeff,

P.S. given my WAV file size exceeds the forum upload limit, I could email it to you?

I may get an external sound recorder, but I'm interested to hear whether of not the sound I'm getting from my current set up would be okay for the pilot show?

Kind regards,
Michael
 
Hey Michael,
Don't know what the broadcast standard in New Zealand is. In the US, we tend to use
the PBS 2007 TOS. It has the average audio level at -17dbs with a peak at -10dbs (for SD
TV) and -3dbs (for HD). Dialog levels may be at -24dbs +/- 2dbs (which would put it around
-20 .. ).
It's important to note that this level is what you deliver the material to them at .. not what
you record it at on your device.
The problem I have with the AF100 is the noise-floor. I work around the noise floor by increasing
the gain of a quality mic-pre and mixer by hitting the AF100 with a stronger signal
and turning down the audio input on the AF100 such that it peaks (on the AF100) around -12db
(or approx .. which is very difficult to ascertain given the AF100's ballistics). I often position the audio
input level on the AF10 around the 10 o'clock position.
Depending on the mic pre / mixer you're using, there's a balance between the mic stage gain
and the master gain as to how much noise you get. The FP33 has great Mic pre's . so I don't think
getting the balance is going to be a problem for you. On less expensive models, this can take some
time to get right.
My advice is to hit the AF100 with a stronger signal .. -12db to -6db (tops) move the signal level
significantly above the noise floor of the AF100. Then, you can take the signal level down in post
to meet your broadcast standard. The great news about bringing the level down is that is also moves
the noise floor down along with the signal level.

Again, if you can *possibly* avoid recording to the AF100 and use a good external recorder, things will
turn out much better (IMHO).

jeff
 
Jeff, hi, and many thanks for your demystifying input on calibrating the mixer with the AF100 - you really cleared it up nicely.

Much appreciated.

Kind regards,
Michael
 
Sorry, Jeff, one last thing.

Could you please tell me if you think either the Tascam DR-100 or the Zoom H4n Handy Recorder would provide a significant step up in the sound quality? i.e. would it be worthwhile getting them, or, staying with recording to the AF102 via the Sanken and FP33?

Thanks and regards,
Michael

Tascam DR-100 Professional.jpg
Tascam DR-100 Professional

Zoom H4n Handy Recorder.jpg
Zoom H4n Handy Recorder
 
Jeff, are you referring to the HD-P2? Not finding the HD2. And how does it compare(preamps) to the DR-680 in addition to the DR-100, H4N Michael mentioned above? Thanks.
 
I think you'll be fine with the Sanken (I assume a CS?) and the FP33. You've certainly got your priorities right by
fronting the AF100 with a very good mic/pre combo. That's the most important thing.

On the AF100, don't use the inputs on mic level .. the mic pre noise (especially with phantom power on) is
unacceptable. With LineIn, hit it with a sufficiently strong signal ( -12 to -6 ) is a good compromise.

We use the HD2 (now HD-P2 .. the newer model) because it has timecode functions and metering that
we can see what we're recording at. The AF100's meters are merely a suggestion of what's going on (slow
and highly inaccurate peaking). The Pre's on the HD2/P2 are quite good. That said, we front them with
either a SoundDevices MixPre or a PSC M4.

We have used the Zoom H4N .. and it's noise floor is lower than the AF100 (in line in mode). The MicPres
are better .. but .. the phantom power will eat the AA batteries for breakfast. The metering on the H4N is
poor, however.

I've used the Tascam DR-680 for a surround sound shoot .. and it was quite good .. but .. doesn't do timecode,
which is a shame. To my ears, the mic pre on the HD2/P2 sounded cleaner and more distinct.

But .. IMHO, you'll be hard pressed to beat the SoundDevices MixPre . it truly is a studio quality pre in a
portable rugged unit. The FP33 is a close second.

I haven't use the DR-100 .. cant' comment on that one.




I did some audio tests with the AF100 when I got it .. and here was my analysis

Line-Level at "5" (12 o'clock) no input:

Line_Level_5.png


Audio: http://onthemarkmedia.net/AF100_audio/Line_Level_5.aiff

It's noise floor is at approx -70 and becomes increasingly noisy from 2k up.
As you can hear in the audio, it's a high-order hiss ... on the HD2 .. dead
silence.

Here's the worst on the AF100 . Mic level .. gain at 10... phantom power on.

Mic_Level_5_phantom.png


Audio: http://onthemarkmedia.net/AF100_Audio/Mic_Level_5_phantom.aif

Of course . this is something you should never ever do . but .. tells you the maximum
noise the camera will put out (as a reference).

Good luck with your shoot! .. I think you'll be fine with the combo you have. But, if you
get into doing broadcast more frequently, I think you'll wind up getting something like the
Tascam HD-P2. If you have a recordist operating the boom, they like to balance using the
mixer at the source .. and they're really into timecode (or should be).

jeff
PS: Remember to record room tone :-)
PPS: Use the HPF on the FP33.
 
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Now Michael..you have to come over and explain all that stuff that Jeff told you... to me!

BTW- do you know that Philip Bloom and Ric Creaser are having an audio workshop on Sunday 18th in Auckland?

Presented by Rode and A2Z

Cheers
Shooter , Auckland , NZ
 
Hi Shooter,

I'd be interested in going to the audio workshop you mentioned.

Do you have any details as to where and when?

Thanks and regards,
Michael
 
I wish I could go. Rode is making some excellent products for video.
The NTG-3 was a favorite on the set of "Lost" because it could get soaked
in moisture and not fry out (like the Sen 416's).
The Rode Blimp gives the Rycote a run for it's money at a fraction of the cost.
Lastly, the Rode PINMIC is an ingenious design to hide the mic in newscast
situations. Not as invisible as a Countryman B3 .. but easier to hide
in plain sight.
They're doing good stuff!

jeff
 
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I think all audio guys are full of it so I would not be surprised.

Sunday is a last ditch effort for me to understand what you guys are actually really about with your mumbo jumbo.

(Actually I have a project and I will be sound man as well as everything else...so its professional development!)
 
Thanks for the details Shooter.

I'm not sure if I will go or not, but it would be nice to meet you at some stage if you have time.

Kind regards,
Michael
 
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