[Ardour-Users] Sync between internal and external sources

[Mark Knecht]

I think you're right Brett. I read his email again and decided I got
fooled by his info about Jack and fell immediately into this old
multi-card conversation.

Sorry Mark!

- Mark

On Wed, Jan 21, 2009 at 7:30 AM, Brett Clark <brett.clark at zirous.com> wrote:
> I think there's a terminology issue.  Im not sure he's referring to the
> HW
> sync during sampling.  I think he's referring to asking about latency
> compensation
> when combining a SW like Hydrogen with a real-world recording (like a
> mic'd amp)
> to be recorded via Ardour.
>
> Ive noticed sometimes when I would be recording and have to "nudge" my
> track to
> get it back in time. I just had that happen last week when I was laying
> a track
> with WhySynth and noticed the timing was off.  I chalked it up to the
> fact that
> im not a keyboard player and did the nudge. ;-)
>
> --Brett
>
>
>
>
>
> -----Original Message-----
> From: ardour-users-bounces at lists.ardour.org
> [mailto:ardour-users-bounces at lists.ardour.org] On Behalf Of Mark Knecht
> Sent: Wednesday, January 21, 2009 9:21 AM
> To: Mark Greenwood
> Cc: ardour-users at lists.ardour.org
> Subject: Re: [Ardour-Users] Sync between internal and external sources
>
> On Wed, Jan 21, 2009 at 6:50 AM, Mark Greenwood <fatgerman at ntlworld.com>
> wrote:
>> I've thought very hard about this question and now my head hurts.. I'm
>> wondering about how, if at all, Jack/Ardour ensures that all sound
> sources
>> stay in sync.
>>
>> Let's assume for the moment that I'm capable of playing an instrument
> such
>> that I'm in perfect sync with a drumbeat.. (this is a big assumption
> but we
>> have to start somewhere.. )
>>
>> I'm using Jack. I have Ardour set to JACK Time Master. I have Hydrogen
> set
>> up to sync to Jack and play a beat. I have Ardour set up to record me
>> playing the bass through my soundcard. I press the Play button -
> Hydrogen
>> starts playing, I start playing, Ardour starts recording me.
>>
>> Question 1 : When I play back my recording of me playing bass, and
> have
>> Hydrogen playing along - are they in sync? Or is my bass part now
> delayed
>> relative to Hydrogen by a value equal to the latency of my sound card?
>>
>> Question 2 : When, at a later date, I mix down by recording the output
> from
>> Hydrogen into tracks in Ardour, does the sync change?
>>
>> I ask because it sounds like I'm not in sync with my drums but I don't
> know
>> if it's me.... It might be that the answer to this is so obvious that
> I
>> can't see it for looking. I do know I can't see it... please help..
>>
>> Mark
>
>
>
> Jack itself really doesn't do anything except use a clock from one of
> the sound cards. We have to ensure that every sound card is using the
> same clock. By using the right external clock and specifically hooking
> it up to all sound cards in all systems they all stay in sync.
>
> It's possible to use a sound card as the master clock if it has the
> right outputs. Those outputs *might* be spdif, word clock or ADAT.
> (Maybe others but those are the ones I've used) you have to enable the
> output to send the clock and then have to enable the other cards to
> use that clock instead of its interna crystal.
>
> Hope this helps,
> Mark
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