Bussing question

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This topic contains 14 replies, has 7 voices, and was last updated by Profile photo of robc robc 12 years, 5 months ago.

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  • #23030
    Profile photo of luciano
    luciano
    Participant

    Hello everybody
    I had a look around but haven’t found an answer to my question :
    – in case I’m deselecting a bunch of inputs from L/R, assign them to two different subgroups , keep one subgroup unprocessed and apply compression,eq on the second subgroup, will that create any phase issues?
    In case that’s not viable, how are you people achieving parallel compression-upwards compression-new york compression and whatever else that is called?

    Luciano

    #29071
    Profile photo of RayS
    RayS
    Participant

    quote:


    Originally posted by luciano

    Hello everybody
    I had a look around but haven’t found an answer to my question :
    – in case I’m deselecting a bunch of inputs from L/R, assign them to two different subgroups , keep one subgroup unprocessed and apply compression,eq on the second subgroup, will that create any phase issues?
    In case that’s not viable, how are you people achieving parallel compression-upwards compression-new york compression and whatever else that is called?

    Luciano


    You could use the “parallel compression” path in the iLive compressor…..will do exactly what you need …also you could search net for one of dave rat’s fine examples on how he uses compression on groups only (not individual instruments) and no compression on vca’s (DCA) to achieve similar results with faster (on surface ) control……

    RayS

    R-72/iDR32/iPS10

    #29073
    Profile photo of luciano
    luciano
    Participant

    Haven’t answered my question at all! I am not interested in how parallel compression works in general. I need to know wether on allen heath systems there is any sort of delay compensation in place for the routing I described in my first post. Or better saying, same inputs ( not assigned to L/R ) going to two different subgroups, one group processed the other one not, are they reaching L/R phase accurate? Are the compressors, eqs inserted on a subgroup inducing latency at all?
    These are the things I’m interested in, as of Ray’s suggestion to watch Dave using compression…. that’s all good stuff but you mentioning compression on VCA’s? Never heard of that !

    #29074
    Profile photo of Lieven-Dewispelaere
    Lieven-Dewispelaere
    Participant

    HI,

    i suppose if you swith the compression on both groups on but only compress one group there will be no latency. When using 2 groups you can change the level between them easily. I don’t think that the ilive uses auto latency compensation and every digital process (EQ,comp.gate) induces latency
    When using parallel compression on one group its not so easy because you have to use the dials in the compression setting section to alter the balance between wet and dry.

    Hope that helps

    Lieven

    T112/IDR48/R72/IDR16/xDR16/2ACEcards/IPad1
    Save a tree, eat a beaver

    #29075
    Profile photo of luciano
    luciano
    Participant

    I usually use light compression on the inputs where it’s needed. I prefer using it on subgroups, obviously. If I’m using only 1 subgroup and apply processing on that one, every time I’m touching the inputs contributing to that subgroup I’m essentially affecting the compressor and all processing level dependent. That’s why I usually use two subgroups. That way, once my inputs are set I never touch them again, if I need to back down the inputs, I do it at the subgroup side. Not to mention that I have separate metering for both subgroups and I can see the contribution of my dry and wet parts, can AFL it separately. So that’s why I’m asking if it can be done on Allen / Heat. I’m doing this on other system and it works perfectly but there’s automatic delay compensation in place. I’ll have to mix on Allen/Heath the first time only on line check ( no soundcheck ) and I need to make sure I can apply some of the workflows I’m used to.

    #29081
    Profile photo of RayS
    RayS
    Participant

    quote:


    Originally posted by luciano

    These are the things I’m interested in, as of Ray’s suggestion to watch Dave using compression…. that’s all good stuff but you mentioning compression on VCA’s? Never heard of that !


    I think you have misread my reply .there is no compressors on vca…..the subgroup is compressed but the vca is not obviously……take a look here for ex: https://www.youtube.com/watch?v=MMMmR1u0CFk

    To go back to your question and my reply ……there is no real need for you to make up compressed and uncompressed subgroups on an ILive because there is a compressor function that will directly assign “parallel compression”…….with dry/wet controls for either a subgroup or many ……look it up in the help menu or download the editor, you can get an idea on how you could use it……agree with lieven though that it’s a little awkward to use the little wet/dry knobs…..so his suggestion of using comps on both groups but only compressing the one makes sense too…….

    RayS

    R-72/iDR32/iPS10

    #29092
    Profile photo of SteffenR
    SteffenR
    Participant

    To answer the question about the latency…
    If I remember correctly, there is no need for delay compensation, as the whole processing takes a given amount of time, if it is turned on or not.
    But I don’t remember the value…

    SRV-AVB
    R-72, iDR-16, xDR-16, Dante

    #29093
    Profile photo of scruffyd
    scruffyd
    Participant

    RayS is right. I read at some point that the mix engine is designed to have the same end-latency no matter what is turned on or off in the processing chain.

    IDR32
    Dante card
    Macbook pro 17
    Ipad2 + mixpad
    Aiport express

    #29094
    Profile photo of luciano
    luciano
    Participant
    Quote:
    Originally posted by scruffyd

    RayS is right. I read at some point that the mix engine is designed to have the same end-latency no matter what is turned on or off in the processing chain.

    That surprises me as I read on this forum people complaining about getting phasing issues when applying this routing.
    Unfortunately I haven’t got access to a AH system but I would appreciate if anybody who has access could give it a go.
    – One try would be a set of inputs assigned to L/R and going thru a subgroup that onboard processing on. Are they hitting L/R the same time, phase accurate?
    – Second try, a set of inputs not assigned to L/R but going thru 2 subgroups, one with processing and the other one without processing. Are they hitting L/R phase accurate?

    #29096
    Profile photo of robc
    robc
    Participant

    Hi Luciano,

    Due to the fact that groups, aux, mains and matrix (mono or stereo) are fully configurable has led to a limitation in coherent latency between some mixes. To date this only represented a problem for parallel compression application using 2 Groups – which was solved by the addition of parallel compression mode on the channel and mix compressors.

    For your application you can mix 2 groups to LR coherently, but you have to pick ‘mono’ sequential pairs. Mono Groups 1/2 are coherent, Mono Groups 3/4 are also coherent etc. Stereo Group1 is a 2 channel pair so its coherent as a LR pair but not with the next Group.

    The confusion over fixed latency on iLive may come from the fact the iLive has fixed processing on all input and mixes so you dont suffer insertion delay or delay due to different processing configurations.

    We are looking into MixBus coherency. It will increase latency as other systems do, but maybe an option mode would be the best way to tackle that.

    Good luck with your first play without even a soundcheck !
    Should be cool with planning, iLive is pretty straight forward, just keep an eye on what your current mix is.

    cheers
    robc
    A&H R&D.

    #29029
    Profile photo of Robert
    Robert
    Participant

    The groups are ideally in phase between group 1 & 2 , 3& 4 and so on . groups with other count 2 with 3 are not in phase, so as no of the groups are not in phase with master, you can check this before your soudcheck with pink noise.
    It does not matter if stereo or mono and switching on or of comp, eq, does not effects the phase issue .

    agutin.com
    1x T80
    2x iDR32
    2 X M-MADI CARDS
    2 X M DANTE CARDS
    desktop+2x RME HDSP MADI
    Macbook Pro,2x Macmini+DVS
    T34-T80-T112-T144
    evolution of SOVIET TANK

    #29030
    Profile photo of Robert
    Robert
    Participant

    robc :)
    we were writing the post almost the same time:)

    agutin.com
    1x T80
    2x iDR32
    2 X M-MADI CARDS
    2 X M DANTE CARDS
    desktop+2x RME HDSP MADI
    Macbook Pro,2x Macmini+DVS
    T34-T80-T112-T144
    evolution of SOVIET TANK

    #29031
    Profile photo of robc
    robc
    Participant

    Thanks Robert,
    I think you put it more simply than I did.
    By the way, the iLive mechanical designer says the T90 was a fine Tank.

    #29032
    Profile photo of luciano
    luciano
    Participant

    quote:


    Originally posted by robc

    Hi Luciano,

    Due to the fact that groups, aux, mains and matrix (mono or stereo) are fully configurable has led to a limitation in coherent latency between some mixes. To date this only represented a problem for parallel compression application using 2 Groups – which was solved by the addition of parallel compression mode on the channel and mix compressors.

    For your application you can mix 2 groups to LR coherently, but you have to pick ‘mono’ sequential pairs. Mono Groups 1/2 are coherent, Mono Groups 3/4 are also coherent etc. Stereo Group1 is a 2 channel pair so its coherent as a LR pair but not with the next Group.

    The confusion over fixed latency on iLive may come from the fact the iLive has fixed processing on all input and mixes so you dont suffer insertion delay or delay due to different processing configurations.

    We are looking into MixBus coherency. It will increase latency as other systems do, but maybe an option mode would be the best way to tackle that.

    Good luck with your first play without even a soundcheck !
    Should be cool with planning, iLive is pretty straight forward, just keep an eye on what your current mix is.

    cheers
    robc
    A&H R&D.


    Hi Rob,
    finally a comprehensive answer.
    Haven’t tried yet double bussing on mono groups, quite honestly I don’t know wether that’s going to affect my mix or not but I guess it’s better than nothing. I usually use two stereo groups for that.
    Having the compression parallel inject option on the input side on individual channels will not really serve the purpose. I have very little time for setting compressors during the show and there is no soundcheck time. I would have preferred doing that on a subgroup while having the original playing so that regardless of how good and fast I’m dialling in the compression the actual mix is unaffected.

    Re : whole system delayed by the fact that automatic delay compensation is in place, no worries at all, especially for FOH applications, doesn’t affect anything.

    Cheers

    #29035
    Profile photo of RayS
    RayS
    Participant

    [/quote]

    Originally posted by luciano

    Having the compression parallel inject option on the input side on individual channels will not really serve the purpose.

    [/quote]

    ….Compressors are available on the groups stereo or mono ,as well as on auxes matrixes and inputs, just engage the parallel path button on the subgroup compressor and you will not only have separate wet and dry components to mix as you please or adjust “live” but also save yourself half the group busses and, this will be phase coherent…….if you really want more flexibility and avoid phasing issues, do not use 2 stereo groups, use a stereo subgroup with compressor and, assign that subgroup to a DCA and then assign the inputs to another DCA (ILive has 16 ).

    When you need more dry level you raise the subgroup DCA (pre compression) and lower the inputs DCA, when you need more wet signal you raise the inputs DCA (post compression) pushing these inputs to the compressor and lower the subgroup DCA ……there are many variants on this as you can assign as many DCA as you have subgroups or use the 2 DCA method , you can also pfl either DCAs/subgroup and adjust to taste, it’s quick and it works…….ILive is a different animal and there’s always more than one way to do things…..

    RayS

    R-72/iDR32/iPS10

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