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139 Views 3 Replies Latest reply: Sep 21, 2012 9:50 AM by ArneLine6 RSS
Ruben40 Just Startin'
Ruben40
43 posts since
Mar 16, 2007
Currently Being Moderated

Sep 21, 2012 3:20 AM

Delay in channel dsp suitable for creating a delay line ? (problem minimum delay time = 20ms !!!)

Hi

In the preset channel dsp you can find a delay.

Can this delay be used for creating a delay line ?

That means, in small venues you can delay e.g. the kick drum signal,

so that the backline- and the PA-kick drumsound are equal in timing.

 

Thanks for help

  • line6jonb Line 6 Support
    line6jonb
    47 posts since
    Jun 11, 2012
    Currently Being Moderated
    Sep 20, 2012 5:41 PM (in response to Ruben40)
    Re: Delay in channel dsp suitable for creating a delay line ?

    Hello,

     

    Yes, you can use this delay for creating a delay line, however there are a number of things to take into account.  The StageScape itself has 1.8 miliseconds of delay from input to output.  Then, you are going to have to use that channel dsp preset on all of your channels and be sure to set the delays for each input to be exactly the same - or just the kick drum in this case.  But there is even more to take into account here.  Lets say, for example, that you have guitar, bass and drums on stage, as well as a Main left and right speaker at the sides.  None of these can be in the exact same location at the same time.  So, delaying your kick in certain spacial arrangements could create the appearance that it is out of time with the rest of the group. 

     

    Now, if you go to the back of the room and delay everything to be in perfect time to make it to you in the back of the room.  That is great for you in the back of the room, but for everyone else, in every location in the rest of the room, may now be listening to a Main Output that is out of time with the rest of the source instruments, because they have a different spacial arrangement comparatively. 

     

    Think of trigonometry, because it all depends on distances, volumes, and spacial arrangement.  The accepted standard for the speed of sound is 343 meters/second and 1126 feet/second.  In that case the 1.8 milseconds comes out to ~2 feet.  Feel free to try this, however be wary that it could cause a good amount of calculation and work for a payoff that may be unnoticable or worse. 

     

    I hope this is helpful. 

     

    Jon

    • Ruben40 Just Startin'
      Ruben40
      43 posts since
      Mar 16, 2007
      Currently Being Moderated
      Sep 21, 2012 2:49 AM (in response to line6jonb)
      Re: Delay in channel dsp suitable for creating a delay line ?

      Thanks for the detailed answer!

       

      At large venues there is mostly no problem, because the main pa sound level is much higher then of the sound level of the backline.

      Therefore a delay between backline and front-PA is not neccesary.

      If you have additional speakers in the audience room than you need a delay line between front pa and these additional speakers.

       

      But let's discuss about the kick drum topic in a small venue.

      Let us assume that the kick drum is located 10 feet behind the main pa speaker.

      Here you get a time delay of  ca 9 milli seconds, where the signal of the front pa is earlier than the sound from the backline.

      If you stand in front of the pa, it can be possible that you can hear some combfilter effects or a let me say a "washy" sound.

       

      Now if you delay the kick drum channel about 9 ms, then both signals are in time.

      I know this effect is only valid, if you stand in front of the main pa.

      I think most people,who listen to the concert, will stand in front of the pa or hear the pa speaker in the back room.

       

      I want to use the channeldsp delay for all instruments that produce this delay between front pa and backline.

      e.g. active guitars-speaker, bass guitar speakr, saxophone, drums,....

       

      But I have one big problem:

      The minimum delay time in the SS is 20 milli seconds.

      Together with the latency of the SS it's too much for using it as a delay line at small venues.

       

      Is it possible to reduce the minimum delay time to 5ms in a future firmware update ?

       

      Thanks for your support.

      • ArneLine6 Line 6 Support
        ArneLine6
        172 posts since
        Mar 14, 2012
        Currently Being Moderated
        Sep 21, 2012 9:50 AM (in response to Ruben40)
        Re: Delay in channel dsp suitable for creating a delay line ?

        Hi Ruben,

         

        It is possible to reduce the minimum delay time and we are looking into introducing line delays. In my experience it can make sense to delay the main system to the backline. Or monitors to each other, which is already very tricky. To delay single instruments in the mix is problematic. Let's take the kick drum:

         

        Delaying the kick but not the rest of the drums (or even band) affects the groove and the sound. For example how tight the kick and the bass work together. And the relation between overheads and toms etc. and kick. Then there is the drum monitor, often louder than the actual drums, which, if you delay it as well, will confuse drummer.

         

        It also not possible to get the "right" delay time for geometrical reasons. If a person stands in the audience in the center the drums are e.g. 30ft away and the left main speaker is 30ft away as well. You could adjust the delay for this case.

        Now, another person stands more to the left of the room and is 30ft away from the drums and 15ft away from the left main speaker. You could adjust the delay for this case. There is no correct delay for both cases.

        This becomes more complicated with sources that are not in the center of the stage. For example the guitar amp is stage left and the bass amp is stage right. What you adjust for people in the right side of the audience will be very wrong for the ones in the left.

        If you look into the phase coherence of these examples it becomes obvious that the only chance to get it right would be: One source, one speaker, one person in the audience.

         

        That said, a line delay in the outputs does not affect the music and can produce a better compromise of all distances from a to b to c to d etc.

         

        Cheers,

         

        Arne

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