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I had my first job with an Amira a few days ago and had trouble setting line level.  I couldn't get the level low enough and while it was only guide track and seemed to sound fine, I switched to mic level and all looked and sounded fine.  It's hard to be specific without the camera in front of me, but has anyone else had the same issue/problem?

Thanks,

Judy

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Hmm. Puzzled. Maybe you mean, you couldn't get it high enough at line level ??

Last Tuesday I set the Amira to line and -10db on my mixer out and it was all fine which was my setting previously on another unit. If you are saying it worked, I have a feeling you were at mic level initially and actually switched to line. Not the other way around.

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The Amira was released with a +8dB maximum line input.  With an updated audio board the max input is +24, which is what you should use if you are feeding it a full professional output level (0dBM to +4dBM nominal), which allows 20dB to 24dB headroom.

If the Amira doesn't have this modification, then, for line level, you should ideally feed it a -12dB to -16dB nominal input to allow 20dB to 24dB headroom.

You can tell whether or not it has this modification by what maximum line level is allowed in the selection menu.  Originally, the selections were Mic or +8.  With the modification, the selections are Mic, +8, or +24).

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Thanks for the comments. On a more technical or perhaps philosophical level, what is the problem of using either the -10 level from a 664 or 633 or mic level from SD devices and setting the Amira levels that way?  I had the same experience as RPSharman, that my line level was too hot and so I worked around it.  I'm so used to sending tone and setting the camera to -20 that I sent mic to mic level so that I did not have to be more careful than I usually am.  I was hardwired to the camera, could listen to the return, sending what I believe to be guide track and am/was hoping that eventually the post people will sync my sound but one never knows.

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Mic level is never ideal on a camera hop, because RF or power noise can get into the low level signal. Also, mic level signals are going into a mic pre, which might be of lower quality than the ones you are using. Some cameras pad a line level signal and go into the mic pre anyway, but not all. Not sure what the Amira does.

As John wrote, 18dB of headroom should surely be ok. But it is very odd that a professional line out doesn't line up to professional line in.

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To me mic level is very often the best solution for cam hops, esp for dinky cams like DSLR and some other lower-end cams with XLR inputs.  I ended up using a mic level out from my G2 scratch feed RX to Amira and it was fine.   Line level feeds to camera only seem to work well for me on more sound friendly cameras like F55 etc.  For a ref feed, whatever works, I say.

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23 hours ago, judykarp said:

On a more technical or perhaps philosophical level, what is the problem of using either the -10 level from a 664 or 633 or mic level from SD devices and setting the Amira levels that way?

Natively, the outputs coming from a professional mixer / recorder such as the 664 and 633 are line level, because this is the nominal level they operate in (specifically, +4dBu pro line level, which equals 1.23Vrms, regardless of impedance). By engaging one of the alternative options for output levels, you're essentially attenuating the signal down to a lower output signal. This attenuation will lead to lower headroom, increased noise floor, decreased dynamic range and SNR of your signal at that stage.

A -10 level would mean you're attenuating the nominal line level signal down by 10dB. A mic level would mean that the nominal line level signal is being attenuated by 40dB. A quick look at the manual also reveals what the maximum output levels are for each output setting:

Screen Shot 2016-04-16 at 9.11.37 AM.png

Thus, if you're looking to feed the best audio possible to another device, feeding an unattenuated signal is best practice. However, if you're only looking to feed a "reference", then attenuating the signal isn't much of a concern. The important thing to do here is to always feed the expected signal level to the input of the next component in the signal chain. This will help avoid distortion or increased noise floors when level setting. I'll finish by saying that all cameras are designed with picture in mind, and very few are designed with audio in mind, so very few of them can actually do pro line level signals well. This is one of the reasons we always insist on double-system when possible, and stick to doing scratch tracks on cameras.

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Agreeing with what Jose said, but adding that there is a range of line levels within which virtually no significant additional noise or nonlinearity will be added.  -10dB to even -20dB attenuation are in this range with well designed circuits, whereas mic level (-40dB to -60dB are not).

I agree, though, that operating at a full professional line level (0dBu to +4dBu) is ideal.

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  • 2 weeks later...

Hi Judy, Andrew from AbleCine, there are currently two audio boards for the Amira, older requires 9-10db of attenuation for Line level input, a Whirlwind 9DB pad in line works fine.

If you send your output from your 633 as AES you can get the camera and Mixer line up perfectly at -20, with this option you can send two channels of audio on one XLR cable and you control the level of the send from your mixer, camera op can't change that send level by mistake or on purpose!

Newer Amiras with an improved audio board do not have this issue with analogue audio input.

Feel free to swing by our showroom to test our Amira and Alexa Mini for audio feeds and TC inputting.

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On a shoot with an Amira last week.  It had the new audio board and things lined up fine.  Got a note back from the editor from the first day saying some of my levels were over modulating.  I wasn't slamming my levels, so I was concerned.  The next day I put tone in (camera hadn't been touched since the first day) and the meters were pinning.  Something had changed from the time I lined things up at the beginning of the day and at some point the levels jumped up by themselves.  The controls were in roughly the same spot.  Kept a closer eye on things the second day after checking tone in and no issues with level.  I did have a back up recording so I was ok that way. 

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51 minutes ago, berniebeaudry said:

On a shoot with an Amira last week.  It had the new audio board and things lined up fine.  Got a note back from the editor from the first day saying some of my levels were over modulating.  I wasn't slamming my levels, so I was concerned.  The next day I put tone in (camera hadn't been touched since the first day) and the meters were pinning.  Something had changed from the time I lined things up at the beginning of the day and at some point the levels jumped up by themselves.  The controls were in roughly the same spot.  Kept a closer eye on things the second day after checking tone in and no issues with level.  I did have a back up recording so I was ok that way. 

So the input level dial was still set at +24?

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This is a fairly common issue with the Amira, I work with a client that has a good number of these cameras and they have been having this issue from almost the start. Although I have not seen the issue with +24 on both channels.  The issue that they see often is that one channel on the camera will jump +16db , almost always during a power cycle, some units seem to do it more often than others but almost all of their 30 cameras do it at some point.  Arri is fully informed of the issue and has been working on a fix for this for a while. 

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3 hours ago, John Blankenship said:

So the input level dial was still set at +24?

I don't get the question John.  I don't think I mentioned +24.  I lined my line level tone out of the Nomad to -20 on the Amira.  I don't think the level dials were moved after that.  Didn't have a lot of time to investigate but we looked at the files that were noted by the editor and they were over modulated just as he said.  I don't recall if it was just one channel or both but I'm almost certain it was both.  Could have been after a power cycle as Chris mentioned.  Kept our eyes on it the next day and no issues even through power cycles.  Paul Dalside who is a friend here in town that routinely works for NFL films always rolls a back up because of this issue.  I found this out later.

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44 minutes ago, berniebeaudry said:

I don't get the question John.  I don't think I mentioned +24.  I lined my line level tone out of the Nomad to -20 on the Amira. 

sounds ugly, good there was a backup.
any reason you didn't use AES out/in?

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