Grass Valley Forums Facebook   Twitter   YouTube  

Go Back   Grass Valley Forums > Converters > ADVC

Reply
 
Thread Tools Display Modes
Old 12-08-2011, 07:37 PM   #1
rhodebump
Junior Member
 
Join Date: Dec 2011
Location: Pittsburgh
Posts: 3
Default ADVC 110 low volumn when capturing problem

Hi,
I have a ADVC 110 that I am using to capture some old camcorder footage using iMovie.

The sound is there, but much too low.

Any tips?
Thanks,
Phillip
rhodebump is offline   Reply With Quote
Old 12-09-2011, 01:04 AM   #2
GrassValley_BH
Demystifier/Analogizer
 
Join Date: Apr 2007
Location: Hillsboro, OR
Posts: 5,785
Default

Need to know a little more about your configuration.

Does the camera have on-screen audio meters, and if so, what level are they showing?

If you're using a lower-end camera, it may only have Monaural output.

If you use a Y-splitter to connect to both left and right, it will drop the signal level significantly.

In that case, run audio only to the Left channel audio input on the ADVC and duplicate the channel in software after capture.
GrassValley_BH is offline   Reply With Quote
Old 12-09-2011, 01:04 PM   #3
dpalomaki
Senior Member
 
Join Date: Oct 2007
Location: USA
Posts: 1,874
Default

Not specific to the ADVC110, but I ran some test onthe ADVC300 audio section. I suspect the 110 behaves similarly. Results at:
http://forum.grassvalley.com/forum/s...ad.php?t=23415
also see
http://forum.grassvalley.com/forum/s...ad.php?t=23381

The followign may or may nto apply to the specifics of your configuration and gear but it does apply to many "average" situations with consumer and soem prosumer gear.

In general consumer gear audio is recorded at an aveage level of -10 dBV or about 0.3 volts. Passed through the ADVC this will result in a signal that averages about 16 dB below maximum digital record level. (Part of the reason for this large difference is to allow for dymanic range and transients in program material.) However, this may look/sound like a low level if the matrial does not have a wide dynamic range.

One solution is to normalize or amplify the sound when editing in your NLE. Just warch you do not introduce unwanted clipping or other distortions. Using some audio compression, limiting, and amplification can yield a higher average loundess (like TV commercials) while staying under the maximum digital record level. There was a recent discussion of tools to asses audio loudness in the Edius forum.
http://forum.grassvalley.com/forum/s...ad.php?t=24418
dpalomaki is offline   Reply With Quote
Old 12-09-2011, 04:37 PM   #4
rhodebump
Junior Member
 
Join Date: Dec 2011
Location: Pittsburgh
Posts: 3
Default

Thanks for the tips. Makes sense to me.

The camcorder has only one output plug, and I have a splitter that I am running to left/right.

I will look at how to duplicate the channels.
rhodebump is offline   Reply With Quote
Old 12-09-2011, 04:51 PM   #5
rhodebump
Junior Member
 
Join Date: Dec 2011
Location: Pittsburgh
Posts: 3
Default Buy preamp or use software?

If you had several hours of video to capture in which you need to boost the sound, would it be worth it to get a preamp, or stick with a software solution?

I see pre-amps for $50 on ebay and I am thinking this would be worth it to get it vs. effort.

Thanks again,
Phillip
rhodebump is offline   Reply With Quote
Old 12-09-2011, 05:44 PM   #6
dpalomaki
Senior Member
 
Join Date: Oct 2007
Location: USA
Posts: 1,874
Default

It would depend on the relative noise floor and other quality factors of the preamp output compared to the ADVC (after post capture gain is added), the capability of your audio editing software, your final product needs, and what you plan for the preamp when the project is done.

If you have a need for a preamp anyway, get one, but be sure it is a decent one. But if this is a one-time job with no need for the pramp after the job is done, I would try a quick test of the software approach on a bit of typical video and if you are satisfied with the results, no need for the preamp.

The quality of a $50 preamp from e-bay would likely be hit or miss - some makes/models are much better than others, and previous owner use/abuse is not always easy to judge.

Whether or not the "Y" splitter is causing an audio level issue depends on the output impedance of the audio source (camcorder) and the input impedance of the ADVC, and may not be well documented. It could be as much as 6 dB difference (worst theoretical case), but is more likely on the order of 0.5 to 2 dB with real world consumer gear.

Last edited by dpalomaki; 12-09-2011 at 05:59 PM.
dpalomaki is offline   Reply With Quote
Old 12-12-2011, 06:42 PM   #7
GrassValley_BH
Demystifier/Analogizer
 
Join Date: Apr 2007
Location: Hillsboro, OR
Posts: 5,785
Default

I recommend not using the splitter run it just to the Left input, and using your NLE to duplicate the audio channel to the other side.
GrassValley_BH is offline   Reply With Quote
Old 12-13-2011, 01:21 AM   #8
kbosward
Senior Member
 
Join Date: May 2007
Location: Australia
Posts: 318
Default

I have used a splitter from a mono camera to ADVC-300 without noticeable drop in audio level. It is much better to do it that way for me because I am using an older computer and an older editor, and duplicating an audio channel in software introduces delays for me in the editing/preview process. It may not be an issue on a newer computer or better video editing software, but my point is that I did not notice a drop in audio level (nor did I need to adjust the audio gain) with my ADVC-300.

Ken.
kbosward is offline   Reply With Quote
Old 12-13-2011, 03:13 AM   #9
SoundFreak_HD
Senior Member
 
SoundFreak_HD's Avatar
 
Join Date: Oct 2011
Location: Netherlands
Posts: 2,376
Default

It also depends on the output stage (type of electronics) used inside the cam (or device), some collapse when you split this way some drop anywhere from 3 to 6dB, it's more of an trail and error thing but I have to agree it's not generally recommended, and should only be used as "in the field" problem solving.
__________________
Tony D.

EDIUS WG 9.5 / MATROX MXO2 LE / WIN10 Pro WS / LENOVO P71 Workstation laptop / XEON E3-1535M v6 / nVidia QUADRO P3000 6GB / Toshiba M.2 NVMe 512GB / Samsung 860 EVO 4TB / 32GB ECC RAM.

EDIUS WG 8.53
/ HDRX-E1 + HDBX-1000 H / WIN10 Pro / DUAL XEON X5470 / SUPERMICRO X7DWA-N / SUPERMICRO SUPERCHASIS SC745TQ-920B / INTEL 520 SSD 240GB / WD CAVIAR BLACK 4TB (many) / 32GB ECC RAM / GTX 770 4GB / 2x MOTU 896HD.


wavearts / neatvideo / tmpgenc / hitfilm / imaginate
SoundFreak_HD is offline   Reply With Quote
Old 12-13-2011, 01:55 PM   #10
dpalomaki
Senior Member
 
Join Date: Oct 2007
Location: USA
Posts: 1,874
Default

Quote:
I have used a splitter from a mono camera to ADVC-300 without noticeable drop in audio level.
That sounds about right. With modern solid state consumer equipment the line input impedance is typically around 10K ohms. The line output impedance is substantially lower, with 100 ohms being common. (This was not the case with older and tube type gear where impedances were typiclly 10 to 100 time higher.)

A 100 ohm source driving a 10K ohm input will see almost no signal drop.
If the 100 ohm source drives two 10K inputs, the drop still remains negligible, on the order of 0.2 dB.

However, if the source impedance is, say 2000 ohms, there is increased voltage drop (abodu 1.6 dB) and if you compare a single input to two inputs on a "Y" splitter there is about 1.3 dB of additional loss.

To get 5 dB of additional loss relative to the unsplit condition the source impedance would have to be substantially higher than the input impedance, say on the order of 35K ohms. (The unsplit and split case losses are about 13 and 18 dB respectively

However, a concern with splitting the signal (e.g., the collapse mentioned above) is the ability of the output to drive the increased load, which is only somewhat related to output impedance. Using the "Y" splitted might cause the signal to clip at a lower level depending on the details of the output circuits. In this case your ears and a waveform montior can be your guide.

Another concern with "Y" adapter splitting is possible interaction between dissimilar inputs; e.g., some sound card inputs may have a DC bias voltage on them that could cause a problem for an input on another piece of gear.
dpalomaki is offline   Reply With Quote
Reply
 
Go Back   Grass Valley Forums > Converters > ADVC
 

Bookmarks

Thread Tools
Display Modes

Similar Threads
Thread Thread Starter Forum Replies Last Post
Low Audio when capturing with Canopus ADVC-300 plmahlik ADVC 11 09-06-2011 04:51 PM
ADVC 110 Capture problem theaburton ADVC 3 02-18-2011 01:00 AM
Capturing Internet Audio with ADVC 110 CoriSCapnSkip ADVC 9 03-13-2009 02:36 PM
Audio hum when capturing with ADVC 110 harixxxx ADVC 6 12-03-2008 01:47 AM

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are Off
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +1. The time now is 04:41 AM.


Copyright 2014 Belden Inc. All rights reserved.