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audio issues with my decklink studio

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Pierre Paré-Blais
audio issues with my decklink studio
on Jan 26, 2012 at 10:14:16 pm

I'm having some peaking issues with the feed comming out of the analogue 1-2 outputs of my decklink. The signal comes peaking (clearly distorting) in areas where my source is clearly not peaking. The issues does seem to be in relation to the volume of my clips, i.e. the peaking occurs in the "louder" sections of the soundbites, but these section while louder are often very far from peaking in actuality. The problem is at it's worse in "noise" type sounds where everything tends to be louder (but still not peaking). In the preference pane I've had to reduce the output level all the way to -12db in order to reduce this effect, put it is still present in the "louder" sections. this occur no matter what software I'm using, in avid with the decklink as my i/o or even simply with quicktime using the decklink as my system output. I've tested the very same soundfiles but using my motu traveler instead and it's all fine, I have to crank the output volume way up to get distortion, and even then the peaking is not as "glitchy" or digital sounding. I've also tried in desperation to feed the decklink into the inputs of my traveler, and the same issue persist.

oh yeah, the audio coming out of the HDMI out comes out fine from my HDTV internal speakers.

The traveler and the Decklink are connected in exactly the same way to my monitors (they both go into a small mixer which routes to my qsc amp). Maybe there is something I don't understand about how the decklink handles its audio outs? at present it's not unberable in so far as in most application I use the traveler for audio out and keep the decklink just for video, but in some cases this can't be done, like in avid or Resolve, which rely only on the decklink to output anything...

Here's how I'm setup:
Mac pro 2010 8-core 12gb ram
Decklink studio 2
Traveler Mk3
JVC 8-track analogue mixer
QSC stereo amp 1200
Both the decklink and traveler are conected with 1/4" to XLR jumper cables into the line inputs of my board.

any help figuring this out will be greatly appreciated! I guess I might want to ask Black Magic support directly, but you guys have been such help to me in the past, and often much quicker to reply ;)

thanks

Pierre P. Blais
Multimedia performance and VFX artist
Pierre P. Blais Productions
Perception Films
http://www.vimeo.com/user1771129


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Paolo Castellano
Re: audio issues with my decklink studio
on Jan 27, 2012 at 10:26:08 am

Hello Pierre,
your problems could be related to the audio connectors; please read this thread http://forums.creativecow.net/thread/124/878439 , you may find the solution there.

Hope it helps,

Paolo.Castellano@ivs.it
http://www.ivsEdits.com
-----------------------
"Post Fata Resurgo"


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Pierre Paré-Blais
Re: audio issues with my decklink studio
on Jan 27, 2012 at 4:05:40 pm

Thanks Paolo,

Let me verify with you, the poster in that thread seems to suggest that all the audio connectors of the decklink require TRS cables, I was under the impression that in the outputs only the output 3-4 (which are joint on one output cable) required TRS, and that the 1 and 2 output (being individual mono outputs) only required TS connectors? If that is the case then that might be my issue, since my xlr jumper/adaptors are both TS to XLR-3, I'll have to try with some TRS adaptor cables, which I think I have in my cable drawer, when I get back home.

Pierre P. Blais
Multimedia performance and VFX artist
Pierre P. Blais Productions
Perception Films
http://www.vimeo.com/user1771129


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Paolo Castellano
Re: audio issues with my decklink studio
on Jan 27, 2012 at 5:41:53 pm

Hello Pierre,
all the Decklink Studio connectors have the same feature (1,2,3,4); Analog Audio Out 3 and 4 share the same connectors with AES/EBU 3&4 and 5&6, but have the same identical behaviour, for this reason all plugs must be 1/4" TRS, for balanced and unbalanced audio.

Perception Films; have you ever had a PVR Perception too?

Happy Editing,

Paolo.Castellano@ivs.it
http://www.ivsEdits.com
-----------------------
"Post Fata Resurgo"


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Pierre Paré-Blais
Re: audio issues with my decklink studio
on Feb 8, 2012 at 3:43:25 am

Hi Paolo,

Took me some time to reply, cause it turned out I didn't have any TRS->XLR adapter after all so I had to make some out of spare connectors I had in my scrap drawer... anyways... it works now! So that really was it. Problem solved!

Many thanks for your help!

Pierre P. Blais
Multimedia performance and VFX artist
Pierre P. Blais Productions
Perception Films
http://www.vimeo.com/user1771129


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Paolo Castellano
Re: audio issues with my decklink studio
on Feb 8, 2012 at 8:59:15 am

Hi Pierre,
You're welcome!

Paolo.Castellano@ivs.it
http://www.ivsEdits.com
-----------------------
"Post Fata Resurgo"


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Andrew Rice
Re: audio issues with my decklink studio
on Jul 17, 2012 at 8:39:41 pm

I'm wondering if I can get some help with this issue too.

The catch with my problem is, I am experiencing the same thing, but I am using 1/4" TRS cables. They are going from the Decklink Studio to a Yamaha MG10/2 Mixer. Then I monitor from there through, either BX-5s or headphones.

I did click the "Use hi-fi Audio Levels" in the Desktop Video 9.5.3 preference pane, under Audio Levels. That helps a LOT, but I still get the crackle/distortion on what seems like peaks, although the levels are clearly not peaking.

Thanks in advance. This is my last hurdle to fully LOVING Media Composer, switched from FCP last year.

Andrew Rice
Kenai Productions
http://www.kenaiproductions.com


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Paolo Castellano
Re: audio issues with my decklink studio
on Jul 17, 2012 at 11:59:33 pm

Hello Andrew,
since you're using TRS jacks, your problem is probably at the other wire end (TRS too? Each TRS going into a mono balanced Input like ch.3 and 4 or 5/6?)

Ciao,

Paolo.Castellano@ivs.it
http://www.ivsEdits.com
-----------------------
"Post Fata Resurgo"


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Andrew Rice
Re: audio issues with my decklink studio
on Aug 18, 2012 at 3:04:14 am

OK, its been a while, I must have overlooked the email i got when you replied. In any case, thanks for your response.

My connection is from a Decklink Studio to a Yamaha MG 10/2

I have TRS ( i am pretty sure mono) from Channel 1 going into the Left Input of a stereo channel on my Mixer, and Channel 2 goes into the Right of the same channel on the mixer.

The Cable is TRS on both ends. I am attaching a pic that shows some of whats going on.

Thanks for any help with this..the distortion is driving me nuts. Its the last element to fix for a smooth running system.



Andrew Rice
Kenai Productions
http://www.kenaiproductions.com


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Paolo Castellano
Re: audio issues with my decklink studio
on Aug 21, 2012 at 2:38:20 pm

Hello Andrew,
many times the reason of audio problem was the TRS jack, but you may have other problems thay I may ignore now.
Have you tried to connect your speakers directly to the BMD outputs? Audio is clean or distorted?
Best Regards,

Paolo.Castellano@ivs.it
http://www.ivsEdits.com
-----------------------
"Post Fata Resurgo"


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Marc Mühldorfer
Re: audio issues with my decklink studio
on Jan 10, 2013 at 3:21:42 pm

I have a problem that drives me mad (and I am lacking some special audio knowledge as well): Audio in Avid is brutally distorted and generally humming like hell.

I have the following setup:

A Mac Pro (early 2009) with a DeckLink Studio 2 card, an Alesis MultiMix 16 Firewire, 2 KRK Rokit 5 speakers and Avid Media Composer 6.5.

I connect the DeckLink card with 2 unbalanced (instrument) 6,3 mm/1/4 inch phone connector cables. Those go into the Line in 11/12 of my Alesis mixer (one channel). I think this is where the problems begin, right? Should I use balanced cables instead? What's about mono/stereo? Are balanced cables mono or stereo or doesn't it matter? Because I was assuming that both the two audio outs of the DeckLink and the two inputs of my mixer are mono, right? Just for info: I am connecting with the exact same cables via a Line6 KB37 audio interface to the mixer and there are no distortions or buzzes in Logic Pro at all.

Then there are the KRK Rokit 5 speakers. I connect them via the balanced TRS outputs to the Main Mix out of my mixer with unbalanced 6,3 mm/1/4 inch phone connector cables as well. I assume it is vital to use balanced cables here as well, right? Because right now I have a bit of humming going on as well only if I turn on the speakers (does the cable really make such a big difference or is there something else going wrong in my system?).

Basically I really would love to know (exactly) how to connect/cable my DeckLink Audio outs to my Alesis Mixer and to my KRK Rokit 5 speakers in order to have crystal clear sound in Avid.

Thanks so much for helping out an audio beginner.


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Pierre Paré-Blais
Re: audio issues with my decklink studio
on Jan 10, 2013 at 3:49:19 pm

Using Balanced cables should solve your problem... at least it did for me. a balanced cable doesn't necessarily mean a stereo cable, stereo is just one of the popular ways to use the connection pattern in the cable. as I have now learned all decklink audio connection require balanced cables. As for the connection to the speakers, in my experienced I've never needed to use TRS, but I am unfamiliar with the particular hardware you are using here. definitely the first step would be to change the cables coming out of the decklink, I suspect this will fix your issue right away.

Pierre P. Blais
Multimedia performance and VFX artist
Pierre P. Blais Productions
Perception Films
http://www.vimeo.com/user1771129


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Jan Vork
Re: audio issues with my decklink studio
on Jun 11, 2015 at 12:07:36 pm

For me it worked to turn down the audio mix -9dB (something I remembered from the pre digital broadcasting audio history). That worked.

http://www.jaydude.nl


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