syncing audio from extrenal multitrack

[guhlenn]

Hi people,

I have an Aaki dr-8 (sorry to mention it again ) and would like to transport the audio through the stereo digital out (SPDIF) however i'm told i will have syncing isuuess, ie tracks running at slightly different speeds. Now i can get a midi syncing card for the akai but it will run me about 300,- is there a cheaper way to do it?


Thanks a lot!
Guhlenn

[stevenagy88]

Guhlenn,

Can you tell me a little more about your computer setup, such as sound card and software?

Steve

[TexRoadkill]

What are you running the SPDIF too? As long as the receiving devices digital clock is set to slave then the sync should be fine. MIDI sync and Digital Word Clock sync are too different issues.

Maybe if you give some more details we can figure out why there would be a sync issue. What would the digital signal need to be in sync with?

[guhlenn]

I'm sorry, i realise now i was being a bit hasty... it';s all clear to me though.

Anyway, I'm in the process of buying a soundcard, i have the dr-8, the dr-8 has the dig out (SPDIF) and 8 analog out. I want to import the tracks i recorded on the dr-8 ( those are 18 bit at 44.1) into my computer. I currently use cool edit but am thinking about sonar, but it's quite pricey....
Anyway, i was told that when i transport the tracks from the dr-8 (two per time due to the stereo out only) I would have syncing issues ( I will have to transport a lot of tracks; i'm gonna record my band and we wanna do it the proper (?) way and record everything seperate on click. )

So this means that i record for example drums (8 tracks) and will need to transport the through the stereo dig out to computer... now i want those 8 tracks to sync up in the end...

I have experienced these issues with an old tape deck with 4 tracks... kick being a little faster then snare and getting worse (logarithmic) I was told by Moskus that when i do the above mentioned procedure i will experience the same syncing issues... i'm talking about the total time of tracks that will differ a little each time i import two tracks to the computer.
So i would need something to sync tracks. cheap if possible...

Hope you can help, hope even more that everything will sync up just fine

Thanks alot
Guhlenn

[stevenagy88]

I am not familiar with the dr-8, but I would say this (a little bit dense and longwinded). For pop- and clickfree digital transfer on S/PDIF you need to set one side on internal clock (master) and have the other side slave to the digital signal on SPDIF. Either your Akai or your soundcard can be the master. Normally you would select the best clock (stability-wise) as your master, but in this particular case that is not relevant, since the transfer is sample-accurate.

Now, this does allow for digital sample accurate transfer, but not yet ensure sync between multiple transfers of 2 tracks at the time. The way to get that is to use MIDI Time Code (MTC), hooking up your Akai and computer through MIDI and have one side generate MTC and the other slave to that code. Most likely your Akai can generate MTC and you can have your sequencer slave to that. Now you can repeat the 2-tracks-at-a-time transfer through S/PDIF, maintaining sync between all tracks.

If the Akai does not support MTC, you need to stripe one track of the Akai with SMPTE and then slave your sequencer to that. You will need a device to generate and read SMPTE. Some MIDI interfaces provide this functionality.

I know this is complicated, but you really need both the MIDI and digital audio connection. A couple of additional points:

1. Your digital master does not have to be your MTC master. In other words: your Akai could provide MTC, while you computer (soundcard) provides the clock signal for S/PDIF.
2. If your Akai has optical S/PDIF, it may support ADAT format on the same ports. That would enable the transfer of 8 tracks at the time. You would then need a soundcard that support ADAT in and out.
3. You can forgo the MTC part if you dont mind syncing up the parts manually in your sequencer after transfer. Provided your digital transfer is sample-accurate, your parts will sync perfectly once you align the starting points.

Let me know if this helps.

[guhlenn]

Steven,

thanks alo. All is possible with the akai, however only if you buy expansion baords..

That shit is expensive. The midi TC baord is the cheapest and will run about 300,-. For 8 tracks i will need the aes/ebu board... 600,- man i hate it. anyway, your telling me that the only problem is starting points?
I would use four clicks anyway for starting alignment (you know the famous drumstick hits...) so that wont be an issue. I was told that even the akai would have small word clock (i'm not sure what i'm talking about here) differences and the SPEED of a track would not be identical to others. If i only need to sync up the starting point that is no issue at all; i will be doing that anyway

So how do i know whether i can have "sample accurate transfers"? i thought i would have that (all the sound cards advertise with it) but then well... i was told i could forget that. trying out mostly just costs money.... and more hardware...

And are there sound cards that generate MTC or SMPTE ? the SMPTE card for the akai costs 350,-

Maybe using the analog out would be more usefull?

MAn, you're confusing me

[stevenagy88]

Sorry for confusing you. I would not spend any money on upgrading your Akai. You can get an entire 16-track digital HDU recorder for the money you will spend.

If the Akai already has S/PDIF out, get a board that has S/PDIF in and transfer your tracks 2 at the time and align them manually. S/PDIF will do sample-accurate transfer if you slave the clock on one end to the other, so you will definitely not have timing issues beyond lining up you tracks.

[guhlenn]

Originally posted by stevenagy88
S/PDIF will do sample-accurate transfer if you slave the clock on one end to the other

This is the part that confuses me, could you explain please (if this is a dumb question, please ignore, i have not yet been able to perform track into computer dumps )

And i'm well aware what multitrackers cost these days (however the akai is a very nice one... ) this is why i'm very hesitant to just buy the midi card...

Thanks alot...
Guhlenn

[guhlenn]

All in all though your telling me my wish has come true? i only need an audiop card with a S/PDIF in? oh my god I AM happy! i can spend all that money on a decent card instead of akai upgrades...
Guhlenn is definately a very happy little boy dancing around naked... Well maybe not naked...

[stevenagy88]

All digital audio uses a clock signal (nowadays mostly with a frequency of 44.1, 48 or 96KHz, S/PDIF defaults to 48kHz).

Now this is important: in S/PDIF the clock signal is embedded in the audio signal!

If the soundcard synchronizes to the S/PDIF clock signal coming from your Akai, playback and recording will stay exactly in sync for each sample that is transmitted. You need to use a soundcard that has the option to use the clock signal on its S/PDIF in-port. Normally this is set in the software that comes with the card in an option that says something like "use incoming clock signal".

[stevenagy88]

Absolutely. Now go put back on some clothes.

[stevenagy88]

By the way, I happen to be Dutch too, but living in Brazil. Glad to help.

[guhlenn]

Ah, well dutch stick together ey...

And i got myself together last night and put on some clothes and all... now that I recovered I would like to thank you and express my deepest regrets for putting horrible visions in your head

Seriously, thansk alot!
Guhlenn