Recording Live Sound on Alesis HD24...

Discussion in 'Digital Recorders' started by Arvida, May 21, 2007.

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  1. Arvida

    Arvida Guest


    It's been a long time since I've posted! That is a good thing though as many of our problems were corrected by the great info I received here!

    Now though..we have another issue!

    In the past we purchased an Alesis HD24 to do live recordings of special services, live music performance, seminars, etc. These recordings were able to be just dumped to the HD24 without much regard to their levels or anything because it was the raw sound. Then, a few days later we'd take the tracks and mix/master them appropriately and spit it out on CDs for people to order/buy. We had time to do it all.

    However, our church now wants to spit out mixed CDs immediately following a service! So, I'm here to see if anyone has any experience with creating a good setup for insta-production from the HD24.

    Here is our current setup...

    - Yamaha 01v96 Digital Mixing Board w/ 32 Channels (16 Channels of Input via digital optical from two Presonus Digimax pre-amps that are outboard and 16 channels of XLR inputs)

    - Two Presonus Digimax Pre-amps spitting out 16 channels via digital optical to the board

    - Alesis HD24 with 16 channels coming from the board via digital optical and 8 channels coming direct from the pre-amps via TRS (We couldn't do all 24 channels via optical because one of our optical outs from the board is in use by HearBack personal monitoring system)

    My main problem is that I have no way (that I know of) to mix on the fly. I have no control over what is getting spit out via the opticals or spit out of the pre-amps. So, it's all messed up when it gets to the HD24.

    I was thinking that I could take 24 channels of optical or 24 channels of TRS out of the HD24 to another mixing console, mix it there and spit it out to CD or something, then I would still have the audio on hard drive and mix on the fly to 2-track out on the second mixing board.

    Or even take 24 optical out from the HD24 to a computer interface and mix down via software to a file on the computer.

    Anyways, given this you have any thoughts or ideas?

    Oh...the way we currently do on the fly stuff is by 2-track out directly from the Yamaha 01v. The problem here is that we don't want to have to keep using a CD as the master. We want it in file form...not to mention that the mix isn't that great coming directly from the FOH console given that we can't really adjust gain levels because it'll effect not just the mix but the live sound as well.

    Any ideas?[/list]
  2. BobRogers

    BobRogers Well-Known Member

    Apr 4, 2006
    Blacksburg, VA
    I'd figure out how to use the two-track out in a better way. It's one thing to mix the service twice when you have the leisure, but not if you have to get the recording out fast. Besides having the mistakes in your live mix preserved for posterity is good for your soul (and motivation for improving your mixing skills).

    One obvious idea is to put the 2-track out through a hardware compressor and/or limiter and then to whatever media that is most convenient. I'd talk to some people in radio about the hardware. What you are doing is a lot like creating a radio broadcast. (And if your church is like ours, that might be what the CDs are replacing.)
  3. Arvida

    Arvida Guest

    Thanks for the reply. You are correct, it is much like any live broadcast. I'm just not having a lot of luck with getting decent sounding recordings and am not sure if it is due to the recording device/media the mix or what.

    A major problem is that some of the levels have no headroom. For example, if I turn the gain up on the drum mics it makes it so I have to turn the live levels down nearly to the bottom of the board just so that the recorded drums are loud enough to be audible on the CD.

    It is a little less true with vocals, they are set at pretty good levels and I have some room, but as I mentioned my drum levels for recording are already maxed and they aren't loud enough on disc. If I back everything else off though and increase the 2-track output levels it all starts clipping. So, therein lies the frustration. =)

    Running the 2-track out through a compressor/limiter doesn't sound too bad though, that'll keep it from clipping out and may soften the mix some. Hm...
  4. Boswell

    Boswell Moderator Distinguished Member

    Apr 19, 2006
    Home Page:
    A few things niggle me here:

    (a) the 2-track out from the 01V96 is just a -10dBV version of the main +4dBu XLR stereo out. If you are using the stereo out for the live FOH, the 2-track is a copy of that and cannot be a different mix.

    (b) the 01V96 has only 12 XLR ins Are you using the other 4 channels as TRS ins?

    (c) I don't see how the HD24 can be involved in an instant CD process. The HD24 is essentially a real-time device on record and on playback. The FireWire data transfer adaptor is little help in reducing transfer times for large channel counts.

    One thing you didn't say was how the stereo image is made up. Are the mic channels panned to their stage positions plus stereo ins from instruments etc? Also, what is fed to the HearBack system? Is it just the main stereo mix or is it special mixes done via auxes?

    My recommendations would be:

    * mix the FOH on the home layers as now

    * Use the HD24 as a recorder only for later mixdowns

    * Consider a different feed (separate 8-chan mixer fed from 01V96 inserts?) to the HearBack so that you can use all 3 01V96 ADAT lightpipe outs to feed the HD24

    * Dedicate 2 auxes on the 01V96 as an "instant mix" L-R pair to be fed out via the S/PDIF out or a couple of the Omni outs. Use an external CD burner with either +4dBu XLR ins or an S/PDIF in (coax or Toslink via converter). All 32 01V96 channels have fader layers for each of the 8 auxes (yes, 16 layers just for auxes), so you can pan in the instant mix by adjusting the amount of each channel in the two auxes it feeds.

    A busy desk!
  5. Arvida

    Arvida Guest

    Hello! Good info and questions...let me see if I can answer, though I wil say that I'm not at the board right now and I didn't set the system up, so I am not entirely sure from memory how certain things are working.

    (A) We have a AUX that has two layers with identical channels as the live mix, however we can control faders on that as well as any 'selectable' settings. So, it is as if it were a totally seperate mix. Then we have that AUX send mixed down to the third layer which is a layer that shows all of our outputs. We set the AUX send mix to go out via the Digital Coax converted to TOSLINK which goes to our CD recorder. So, you are right, it isn't really 2-track is it? =)

    (B) The 01v96 does have 12 XLR ins and we use two of the four TRS for microphones. However, it also has the built in optical and we added the card that allows us to use even more optical. In total we could run 24 channels of audio into the board via the optical slots. At this time we have two outboard pre-amps that feed into the board through the optical slots, thus allowing 16 more channels controllable on the second layer of the live mix and whatever other mixes.

    (C) My thoughts were to not only record to the HD24 but to take all 24 outs from the HD24 to a seperate mixing board which would then be connected to a 2-track out to CD or digital coax out to the computer. That way we would have it on the disk if needed and we could also mix the outs from the recorder on the second mixing board without interfering with the live mix...not to mention it would let us boost/drop gains and levels giving more overhead. It works in my mind, but I have no clue what it may sound like. =)

    We don't have anything panned. I haven't messed with this at all for the live mixes. Though, when we have special events or music and I record on the HD24 we do this some.

    The HearBack runs out from the board via an optical cable, which then interfaces with the HearBack rackmounted unit...which then runs to each persons personal monitor.

    Each person has a level knob for Vocals, Guitar 1, Guitar 2, Bass, Drums, Keys, Piano, and one other one that I can't remember. Those are all routed via the board software to be sent out through the optical. The guitars, bass, and piano are all going direct, each on one channel of the opitcal. The others are all mixed down so that all vocals are on one send, drums on one send, etc.

    I think your recommendation is the same as we are doing now, sending the instant mix out on the AUX. It just isn't cutting it, there isn't any headroom in levels and if we adjust our gains it affects the live mix.

    I'm going to be doing some overhaul of the system soon, getting rid of some loose ends, cables not in use, etc. So any other thoughts are appreciated.
  6. Boswell

    Boswell Moderator Distinguished Member

    Apr 19, 2006
    Home Page:
    Yes, that would work but involves extra D-A and A-D conversions. My suggestion was to do this in the 01V96 using a pair of aux layers, but you would not be able to EQ the channels separately for FOH and CD mix. You do need to plan the gain staging carefully to make sure your headroom is available where it is needed (see later).

    Then all the better that you use panning via variable levels to two separate auxes for the CD mix. You can get away with mono on the FOH where the visual side of things provides the spatial cues, but a mono CD these days is sort of dull. Judicious panning on the CD mix would give an illusion of spatial layout.

    In my scheme, you would use the 01V96 buses for mixing the vocals, drums etc, and output these via omni outs to the HearBack. It means using the analog inputs of the HearBack rather than the ADAT, and taking the single channels (guitar, bass, piano etc) direct as now. This is all really to free the third ADAT on the 01V96 for the HD24.

    Then it isn't the same as what I'm recommending. Your headroom is independent of mix and depends only on the gain trim settings on all the channel inputs. Turn these down to get more headroom, both on the 01V96 and on the Presonus external preamps. Make up the gain (if needed) digitally. You have up to 12dB extra available via the dynamics processor on each channel (even with no dynamics set) and a further 10dB on the channel faders for the FOH (but not the auxes).
  7. Arvida

    Arvida Guest

    That last thing you mentioned sounds interesting. I'll take a look at my gains and see what I can do digitally to give the instant mix some headroom. Thanks for the info.
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