Re: Core Audio and DAE together - avoiding timing

Message posted by ricky <ricky-3mT5L/[email protected]>:

hallo guys you will probably be happy reading the post i've done in logicpro forum, i've finished testing it yesterday and result was not the best but enough to make me happy, i copy paste here:

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Hi all, i had promised myself that if they will not improve ESB in logic8 i search a way to have more flexibility from natives to tdm.

so, logic 8 is out and esb still sucks with his only 8 out.
i've bought an old Digidesign ADAT bridge, i get rid of my 1622 (that was nearly unused) and then i've taken an old motu 2408, that has 3x8 adat in/out

my objective was to keep also esb opened, to reach stunning 32 out from natives to tdm and 24 fantastic input from tdm to natives.
this objective driven me crazy in the last 2 days, and i can say that it's possible but logic introduces very bad timing issue when you use everything, so i had to create a sync channel (a square waveform used as a clock) and then use a biduleAU (with a reaktor ensemble in it) in every core audio channel to resync everything.
I've got a nearly sample accurate result (+-10 samples). the probem is that every bidule uses 2% cpu.. so imagine in a big song i have half processor used for resyncing core audio.

while i was testing i have discovered timing issues even between a core audio EXS and a core audio track with the same exs sequenced bounced, they was flanging a lot instead of playing at higher volume (in a sample accurate daw having 2 identicals signal only push up the volume, and doesn't create any flanger effect).

for this reason i've decided to strat from scratch again and do some testings, this is what you have to do if you want to use core audio with TDM without loosing sample accuracy:

1 - turn off DTDM, or delete all esb channel from mixer, and remove any esb related input from the TDM mixer.
2 - delete all TDM audio tracks, you can't use TDM audio track. (note that you can still record audio uusign TDM a/d converters, but you have to route the signal to Core audio and then record enable a core audio track)
3 - remove all esx24tdm you have

that's all, if you respect this 3 points core audio will stay sample accurate, and this is great, i was already about to cry for having trashed 700€ of hardware.
obviously you will have latency when routing in and out from tdm, but this latency is fixed, so just do a premaster for all tdm stuff taht doesn't come from core audio and put a time adjuster with the sample delay value.. in my case is quite low (256motu+64tdm = 320).

note that also bounces can't be done in TDM, you have to reroute the master to core audio for the final bounce.

Advantages:

1 - you can use core audio to solo.. as tdm solo is bugged right now.
2 - you will have 24 out from native to tdm
3 - you will have 24 out from tdm to native (!!!)
4 - you do not have to get pissed off again with stereo splitted files, saving lot of space on hd and lot of convert time. (and lot of space in arrange aswell, not to mention lot of space in logic control that is bugged and doesn't hide the second audiotrack anymore)

Disadvantages:

1-you have to buy new hardware
2-latency when routing in and out from the 2 systems (but is fixed so can be easily avoided)
3-you can't use tdm audio tracks and ESB or EXS24tdm

(note that you can still use auxes for midi controlled tdm instruments like virus or bruno/reso)

i only have tested latencies for now so i have nothing more to say, but i'll keep this thread updated when i start doing some music next week.

i've not disabled direct tdm, i've done 2 autoloads, the first one is mainly tdm + esb, and i will use it when i have to record a lot of external audio or just do mastering and easy stuff, the second one is core audio + tdm.
the idea is to have the core audio as your main workplace, and use tdm like a mixer, with all his input + 24 in from core audio + 24 out that can be useful to use like sends/returns.

Fantastic, can't wait to start!!


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i can provide you an autoload to stay synched even with everything opened, but i strongly suggest you to have at least a quad g5, in addition you need a licence for both reaktor and bidule, if you want more information about how i have synched everything i'll write it.
i've used bidule cause reaktor5fx sidechain doesn't works in logic 8, so i insert bidule sidechain and inside that a reaktor istance.


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