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  1. Default Remote preamp gain control/save/recall

    Is there any way that SAC can be used to set remote preamp gain so that this is also saved/recalled as part of a scene?

    (if yes, is there any standard control method/API for this?)

    If not there's an obvious gotcha...

  2. #2

    Default Re: Remote preamp gain control/save/recall

    No gotcha... just adjust your mic trims on your hardware down a few db... and use the Att control in SAC to make up the gain difference...

    I set my mic trims where they should be... then drop a notch or two... maybe drops tthe signal about 6db... now I make up the gain with the Att control... SAC is so quiet, there is no noticable noise difference... and now I have complete remote control of mic trims with no special hardware needed... no special protocol/API needed... no special VCA circuit in the mic pre gain stage (noisy) needed.

    Its all good.

    Bob L

  3. Default Re: Remote preamp gain control/save/recall

    Quote Originally Posted by Bob L View Post
    No gotcha... just adjust your mic trims on your hardware down a few db... and use the Att control in SAC to make up the gain difference...

    I set my mic trims where they should be... then drop a notch or two... maybe drops tthe signal about 6db... now I make up the gain with the Att control... SAC is so quiet, there is no noticable noise difference... and now I have complete remote control of mic trims with no special hardware needed... no special protocol/API needed... no special VCA circuit in the mic pre gain stage (noisy) needed.

    Its all good.

    Bob L
    I'm not thinking of small gain changes during a gig here, I'm thinking of recalling a scene when the channels have been used in the meantime for a completely different band where an input that was used for an acoustic guitar mic (50dB gain) is now connected to a keyboard (20dB gain)...

    ...and comes through the monitors 30dB louder than it should be :-(

    (the Brikworm only has coarse gain steps of about 12dB, but different channels could be 2 or 3 steps apart)

    If there is any kind of standard (or scriptable) protocol for preamp gain setting this would a useful feature for SAC to have -- the user would have to provide some kind of file (preamp-dependent) to say what the gain steps are and what control sequence is needed to change them, but this can't be that difficult.

    I think the Brikworm uses the ADAT embedded control channels to set the gains, the data right now comes from a standard serial port but could presumably be written directly from ADAT.

    Ian

    P.S. Yes of course you should always start with all faders down and channels muted, but you know what it's like when you're in a tearing hurry because the van with the PA arrived an hour late :-)

  4. #4
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    Default Re: Remote preamp gain control/save/recall

    AFAIK, there is no standard control scheme, even on Ethersound which can carry control signals. I've also never seen anything but audio for ADAT, no control channel to be passed besides the clock. That'd be my ideal, maybe someday there'll be a standard remote protocol but as of now, there's nothing. There's not even a standard networked audio protocol. There are some standards but you'll get varying features, varying implementations by the manufacturers, bit of a nightmare.

    You do have +20db of gain within SAC itself. My thought was that if you set -16db as your average signal point, then you've got some leeway either side of that to boost or attenuate the signal without clipping your input.

    I'm helped a little by my DI's. The Radial J48's I use have a very hot output as compared to my Countryman Type 85's. Acoustic guitar and bass usually get the J48's and naturally hotter things like keys and e-drums get the Type85's. Vocalists are usually within a 20-30db range, at least the good ones are. I haven't run things like this yet, but it seems workable in theory and worth some practice. Others have mentioned this as a gain method.
    Might be nice to have another 10-20db of boost, but maybe it's as it is because Bob tested things and if you have to apply more than 30db of gain in software your signal to noise becomes noticably higher with the ADA8000's and/or your dynamic range is severely limited. It seems having more boost gain than attenuation gain for a channel would be helpful since -16db is the nominal indicated by the meters. So unless you've got 40db of headroom above the 0db clipping point, there's not all that much you'd realistically want to turn it down.

  5. #5
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    Default Re: Remote preamp gain control/save/recall

    I did a show where we had three bands so I set up different channels on the SAC... I had 72 to choose from. Then I just set my gains on ADA8000 for 6 DB lower than I needed. This worked out OK as I had the time to sound check all three acts before the show started. If we did not have sound check I think we would have been reaching for the gains on the preamps. Generally I have used the channel strip gain control to make up or attenuate gain and have not had any negative results.

    I do intend to expand my system to use at least 52 channels of preamps (matching my big led sleds) so that I can have alternate channels for these events. In a festival situation I am never doing a sound check so this will be the only way to keep the gain structure intact.
    I have avoided using SAC for any festivals yet due to BE requesting certain other digital consoles.

    We are gaining traction here and some of my regular acts are requesting that "computer thing"..... it sounds great!

    OGO

  6. Default Re: Remote preamp gain control/save/recall

    Quote Originally Posted by gdougherty View Post
    AFAIK, there is no standard control scheme, even on Ethersound which can carry control signals. I've also never seen anything but audio for ADAT, no control channel to be passed besides the clock. That'd be my ideal, maybe someday there'll be a standard remote protocol but as of now, there's nothing. There's not even a standard networked audio protocol. There are some standards but you'll get varying features, varying implementations by the manufacturers, bit of a nightmare.
    I was afraid that would be the case -- the problem is that until systems like SAC become more common everyone can devise their own system (and does) because it's all closed and proprietary. It's only when people want to combine front-end hardware from one supplier with interface hardware from another and mixer software (or hardware) from another that there's a need for a standard.

    This has only happened so far with point-to-point audio data-only formats like ADAT/MADI/SPDIF/AES (AFAIK Ethersound/Cobranet define the data/control format but not standard protocols/meaning) but nobody's really considering how to integrate all the hardware with a unified control method -- no "joined-up" thinking.

    Another example is the fact that though the PC running SAC has perfectly capable local I/O for audio (mic, line, SPDIF, headphones) and the means to store/play the material (CD, MP3, WAV, OGG...) and build/maintain music libraries/playlists, there's no simple way of getting all this to interface to SAC because of the ASIO driver model.

    (I understand why ASIO enforced this, but it seems crazy to have all that audio storage/indexing/playing power sitting there unable to be used when many people have their entire music library available on a PC)

    Ian

  7. #7
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    Default Re: Remote preamp gain control/save/recall

    Quote Originally Posted by IanD View Post
    I was afraid that would be the case -- the problem is that until systems like SAC become more common everyone can devise their own system (and does) because it's all closed and proprietary. It's only when people want to combine front-end hardware from one supplier with interface hardware from another and mixer software (or hardware) from another that there's a need for a standard.

    This has only happened so far with point-to-point audio data-only formats like ADAT/MADI/SPDIF/AES (AFAIK Ethersound/Cobranet define the data/control format but not standard protocols/meaning) but nobody's really considering how to integrate all the hardware with a unified control method -- no "joined-up" thinking.

    Another example is the fact that though the PC running SAC has perfectly capable local I/O for audio (mic, line, SPDIF, headphones) and the means to store/play the material (CD, MP3, WAV, OGG...) and build/maintain music libraries/playlists, there's no simple way of getting all this to interface to SAC because of the ASIO driver model.

    (I understand why ASIO enforced this, but it seems crazy to have all that audio storage/indexing/playing power sitting there unable to be used when many people have their entire music library available on a PC)

    Ian
    There is a standard if you use Yamaha add-on cards in a Yamaha console. That's about as close as you'll get. Unfortunately the lack of a clear standard also impeeds progress IMO on release and adoption of digital snake systems. My thought before SAC was that no digital mixer should release without remote headamps. That'd be the worst for us though, since then we'd probably never get remote preamps in SAC unless they were designed specifically for SAC. There's not much call for them that I've seen in the studio world and that's mostly where we live with SAC though we use the hardware for live as well.

    I hear you on the multiple interfaces side of things. Buffers and latency though are the biggest problem. Fortunately you can route through digital I/O and essentially never leave the computer. The RayDAT is nice with its AES breakout cable, giving me an easy cable-free loop for playback and leaving the SPIDIF I/O for a FOH stereo record if I want. THe RME DirectSound drivers nicely provide a DirectSound device for each stereo output pair. In contrast to my M-Audio device it makes making playback and SAC routing simpler. It only provided the first Software return pair as a DirectSound output, which is also what the default arrangement for SAC wanted to use for output 1/2. Just made the mental mapping tougher since SAC out 1/2 goes to Software 3/4 which then has to be routed to whichever hardware output I needed (ADAT1 1/2 for the XLR outs). Things that are easy to lose track of when you're needing it all up and running in the next 30 minutes and the stage inputs still aren't set.

  8. #8
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    Default Re: Remote preamp gain control/save/recall

    Sounds like you'll have to solve this in hardware - RME Micstasy or Aphex 188.

  9. #9
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    Default Re: Remote preamp gain control/save/recall

    Quote Originally Posted by IanD View Post
    Is there any way that SAC can be used to set remote preamp gain so that this is also saved/recalled as part of a scene?

    (if yes, is there any standard control method/API for this?)

    If not there's an obvious gotcha...
    As you have found out, the answer to this question is basically... No.

    There is definitely no standard or anything even close to it. There are some protocols that a manufacturer can license and use and hence multiple manufacturers should be able to talk to one another. (EtherSound and CobraNet) But as has been pointed out both of those protocols only standardize the audio data transfer. The control protocol is specified as to how it will be transported over the network, but I have yet to see any manufacturers share with others how to make their remote preamps work, except with their own equipment. Or you might find something where one Harmon company's gear can talk to another Harmon company's gear. But that's about it.

    I suspect the day when SAC will be able to have control of remote preamps directly is a ways off. Even if Bob wanted to do it, we are a ways off before the manufacturers are going to share that data and make it even possible for that to happen I'm afraid.

    I spent a great deal time studying all the various digital snakes (although I missed the Brikworm...LOL..) a couple years back and have since done my best to keep up with the latest trends. Unfortunately they all seem to think theirs is the best and only thing you'll ever want to use, and I have yet to find one that I think it perfect for theatre where we need multiple drops in locations all over the place, rather than a typical concert environment is point A to point B with some sub snakes. At least not ones that make financial sense over just running standard analog lines, or using ADAT extension or just CAT5 for audio lines. So that is why I just ended up with the audiorails in one of my installed systems. Of course in that venue, having someone on stage with a walkie to adjust gains is no big deal since it's a college and there is plenty of extra labor available for that sort of thing.

    You'll probably just either have to adjust all of them by hand or get some preamps that have a controller with memory slots that can be recalled. I never needed that, so I have no recommendations.

    Richard

  10. #10
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    Default Re: Remote preamp gain control/save/recall

    Quote Originally Posted by IanD View Post
    I think the Brikworm uses the ADAT embedded control channels to set the gains, the data right now comes from a standard serial port but could presumably be written directly from ADAT.

    Ian
    Nope.

    The ADAT lightpipe carries up to 8 channels of digital audio and a wordclock. That's it. No data channels. All the control data for the old ADATs was some type of 9 pin sync protocol. I suspect it was just some hacked rs232 they made up. But it was all seperate from the audio transfer. This is why some sound cards have a 9 pin ADAT sync input and/or output jack.

    Richard

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