SPDIF with slave clocking

Quote from Ingolf

It would be great if the aggressive undertones finally vanished from this thread.

This!

Thanks for the detailed explanation CK, you didnt have to provide one, but you did. And for that I am thankful. Just to be clear - I never claimed that the GT-Pro could slave up to my audio interface, just that it 'seemed' to work when I connected it up for the first time. But then so did the Kemper (and I never gave it a second thought for reasons that shall soon be clear).

I guess ... I underestimated the complexity of SPDIF clocking in the MI. I work in telecom, and in our world, deriving clock information from an encoded data stream is considered pretty basic technology. Again, my mistake to expect the same from a different bunch of equipment, but I remember reading somewhere that the SPDIF data stream does contain the encoded clock - and again, I think this is how my current interface can slave up to the Kemper (or any other SPDIF source), right? It must be deriving the clock from the source signal, right? Anyway - this was largely the reason for my assumptions.

Again, I do understand that this may be a hardware limitation (decisions made in choosing parts early on, etc. etc.) that cannot be worked around, or it may require some crazy stuff to happen at a very low level to make it work. In either case, not trying to be a smart-ass here (even though Im sure many of you are thinking this right now :)). Neither am I expecting that this should work someday, because it's really not a big deal for me. My interface has decent converters, and I am very happy with audio performance as it stands today. I am also more than thrilled with what the Kemper can do - I mean ... the features on this thing are simply amazing - second to none. Add that to clean pristine audio - and Im happier than a pig in $hit :)!

More importantly - the attitude demonstrated by CK and the mods here at the forums is ultra-cool, and I like the fact that the product I bought is so well supported. I mean who can ignore the amazing updates (Just updated to 2.4.2 Release, as I type this, and I still like what I hear). Looking forward to writing some awesome stuff tonight ...

BTW, My Older MOTU 828 Mk II does have Word clock in/out connectors, so can the Kemper somehow use this? I think not, since I dont see anywhere I can connect this up. Is there some way this could work?

Keep up the awesome work team Kemper!'

Quote from Animus

I get not allowing higher sample rates but what I am talking about it allowing slaving just at 44.1 kHz.

Do you have other devices connected as well that needs to be synced?

Quote from Jammer1

This!

I concur. I've tried to be as civil as possible amid misinformation, threats and insults being hurled around by a single disgruntled user.

At the end of it all, I was told: "Oh it doesn't matter what you say".

I'm not dumb. I realise when someone is trying to talk down to me.

If you read through the thread, you'll realise it doesn't matter if I say something or Mr CK something or someone else says something about the reasons for SPDIF being master, or a workaround for this simple issue. The user has been consistently complaining that this is a problem with the Kemper, when it is in fact an intransigent attitude at the user's "professional studio" toward recording anything with a 1/4" cable or making use of their multiple SRC converters and word clocks, which they can buy no end off. It is only in the most recent post that the user has changed tack to saying there should be more digital output options.

That has been the general vein of this thread and I got tired and intervened. Anyone is free to read Mr CK's explanation, he sums up his reasons for keeping the Kemper slavery free really well

Quote from lightbox

You state that different digital audio formats wouldn't increase audio quality. That's not entirely true. In a simple home setup you're probably right.

I was referring to different sample rates only.

Quote from lightbox

S/PDIF has been a consumer audio technology from day one. For simple home audio setups it might have been sufficient but in the pro world it's never been a go-to solution. The only digital audio format close to S/PDIF that had some acceptance was the ADAT protocol (48kHz) ... probably due to the lack of better alternatives. And this might have been the reason for 48kHz to be an industry standard in some audio related fields until today.

I cannot see a reason why Spdif or Toslink is to be considered consumer audio technology. Can you? The Hardware technique and protocol is overlaps with the AES/EBU or MADI (or ADAT) protocol. A large number of professional audio interfaces support those interfaces.

Quote from lightbox

You've stated that most of the pro audio industry are reluctant to add proper digital audio I/O capabilities with very few exceptions. I want to state that the opposite is true, imho. All serious pro audio equipment manufacturers offer a plethora of options.

I was explicitly refering to the Music Instruments Industry

Quote from lightbox

Sadly your prior posts had given me the impression that you're not planning to improve on the current state. Hopefully just a misunderstanding but the way I read it until your long post above it seemed like you completely ignore the need for something better than S/PDIF. That's why I called you ignorant.

I usually don't talk about future improvements. You can of course call me ignorant for that
But what do you mean by "better than Spdif"? Did we talk about it before?

Quote from lightbox

Only thing that still worries me is the fact that you keep asking us to press the pro audio interface manufacturers to add capabilities (S/PDIF + SRCs) they likely won't ever implement because they can't be considered pro level digital audio connectivity. You better change your mindset and offer existing pro level digital audio connectivity in a future Profiler (and Virus) incarnation. For a pro user it doesn't even matter a lot which technology you choose. If you (e.g.) think that word clocked AES/EBU through XLR isn't your preferred technology for some reason, offer something else ... or find a way to discuss available options with those seriously interested in pro level digital audio connectivity.

Your post seems to imply that Spdif is considered to be a consumer interface only even today. I cannot see this circumstance. Spdif is a widely supported interface, found on many pro grade audio interfaces. Toslink was even more consumer grade by its first definition, until it was ennobled to become the ADAT lightpipe standard, without the hardware getting changed. AES/EBU is considered to be the pro standard, but the only significant difference is the use of XLR connectors, making it road proof. That's all.

Quote from lightbox

Not necessarily a separate word clock. If your audio interface provides a word clock output (like the Focusrite Liquid Saffire 56 or RME Firefaces) you can use it, of course. The separate word clock generator is only required if you have e.g. multiple studios (mixing/mastering/recording/editing rooms) and want to have every studio sync'ed to one central master clock.
I haven't seen an audio interface that provides a word clock input but lacking a word clock output.

lightbox, thanks for the info! Just so I'm clear.. have you actually used the Behringer unit with the Kemper unit as a slave to your audio interface? I'd just like know before I go buy.. thanks again for clearing it up.

Yes I have .. I use 2 of them actually, because I have my semi-pro home studio set to 48kHz because I do lots of stuff for video/broadcast ... same like in my main job which is a MUCH bigger production facility. Two with my Profiler because I use the digital connectivity for re-amping.

Quote from lightbox

Two with my Profiler because I use the digital connectivity for re-amping.

so I need two of them for amping/reamping I/O? What is it only one direction, not two? I'm not getting your workflow... How are you wiring yours? I'd have thought I'd simply wire SPDIF out from the KPA to the Board IN and the board out to the KPA IN; then control reamp via KPA switching... What am I missing? I gotta get this done so no more master issues! I'm sick of it. (but love my profiler

Thanks man!

Most likely you have another workflow than me.
As I said before, I'm 100% on 48kHz, so I need to sample rate convert to and from the Profiler's 44.1kHz @ S/PDIF
So basically I don't use the Behringer SRCs for slaving the Profiler only. That's why I need 2 of them.

If you're recording 44.1kHz you don't even need one of them ... as long as you don't mind to sync your interface to the Profiler when you're using it.

I stopped using SPDIF altogether this weekend. I'm not sure what the issue is, but I'm spending too much time troubleshooting so I just use the analog outs and it is fine for me. It is dissappointing, but not a big deal. So you know, I use a MOTU 828mkii which sync's fine internally or externally to other devices (like my Lexicon MPX1). It seems to sync intermittently with the KPA. Often when I take a break and come back, there is tons of clicking and popping. Also, the MOTU seems to lose the lock on the clock often and the MOTU blinks back and forth between 44.1 and 48khtz. I have no idea what is happening . . . . bad cables, problem with the MOTU, problem with the KPA hardware or softwareetc. It has worked well for me in the past, but just not lately. As long as I keep the MOTU set to internal, all music coming from the computer is perfect, if I switch back to the KPA as source, problems begin.

I'm not complaining, just putting my experiences out there for KPA or others benefit.

Regardless, the KPA is still awesome.

It sounds like it maybe related to your MOTU.

Ive been using the Focusrite Sapphire 6i6 with Kemper and Logic via SPDIF for 4 months now. I set the Focusrite Sapphire routing software settings (synch to SPDIF and rate to 44.1) and havent had one lick of problems with the workflow.

Hey djazz,

Im using a MOTU 828 MkIII traveller, no issues here. Going into a MAC (Logic Pro) though, not sure what you're going into. Of course, I set the MOTU to sync the clock from SPDIF. I've not had issues with my older MOTU 828 MkII as well.

HTH.

It very well could be the MOTU 828mkii as I have had an issue with it before. I sent it back to MOTU and for $100 they sent me this refurbished one a few months back. I am using a Mac as well. I never like blaming anyone because 9/10 times the fault points right back at me :). I do have my eye on the SPL Crimson interface as soon as wife stops spending money on her iphone in-app purchases for Hay Day.

I ended getting the Focusrite hardware because several Kemper/Logic users here on the forum spoke of good experiences with it.

Im glad I got it, because at first I needed a bit of guidance on settings in the Focusrite and Logic software. Tech Support at Focusrite was great and got me up and running in 15 minutes.

Quote from lightbox

Most likely you have another workflow than me.
As I said before, I'm 100% on 48kHz, so I need to sample rate convert to and from the Profiler's 44.1kHz @ S/PDIF
So basically I don't use the Behringer SRCs for slaving the Profiler only. That's why I need 2 of them.

If you're recording 44.1kHz you don't even need one of them ... as long as you don't mind to sync your interface to the Profiler when you're using it.

Thanks.. I understand now... I'm staying in 44.1 the whole round trip but I have issues if I don't use the Kemper as Master... I get clicks and pops and drop outs.. so that's why I was so interested.. Looks like I only need one!! that's great! Thank you again! yeah I hate KPA as Master... it's a mega pain in the buttocks locking things up then unlocking when I don't use/need it... then resetting everything when I need it again.. just a pain.

Quote from DukeOURL

... it's a mega pain in the buttocks locking things up then unlocking when I don't use/need it... then resetting everything when I need it again.. just a pain.

This is the most obvious pain, yes. But there's one more that can be much worse.

Scenario:
You're tracking some guitar track using a nice rig through analog Master Outputs. Of course you've setup a zero-latency mix using the analog Master Out from the Profiler to monitor the rig in combination with e.g. the drum & bass tracks. But in the background (kind of unattended) you record the DI track through S/PDIF at the same time for future reamping.

Problem:
While recording you don't even notice if you forgot to sync the interface to the Profiler's S/PDIF Out (or sync is lost for some reason) ... because you only monitor the wet track for obvious reasons.
You only notice the pops and clicks when you try to actually use the DI track to reamp ... maybe a couple of days or even weeks after you've recorded.

This can potentially be a VERY expensive problem (if you need to re-record) or at least get you into some kind of trouble.

Solution?
I don't think it's a good idea to ask the recording engineer to always keep an eye on the DI track as well. Time constraints make it close to impossible to always double-check.
So I think there must be a more robust solution for professional use of the digital audio interface. Something you setup once and then rely on it with no effect on your blood pressure. And this would be a slaveable unit, imho.

Just my 2 cents, as always

Quote from DukeOURL

Thanks.. I understand now... I'm staying in 44.1 the whole round trip but I have issues if I don't use the Kemper as Master... I get clicks and pops and drop outs.. so that's why I was so interested.. Looks like I only need one!! that's great! Thank you again! yeah I hate KPA as Master... it's a mega pain in the buttocks locking things up then unlocking when I don't use/need it... then resetting everything when I need it again.. just a pain.

So the interface stops working when no master signal is received?

Quote from ckemper

So the interface stops working when no master signal is received?

no.. it works... just poorly. for reference, I use a Yamaha 01V96i as the interface; SPDIF in/out to the KPA for DI and Amp noFx and I record the Main analogs with Fx for reference. I run USB (16 ins/16 outs) from the 01V to the Mac.. Before the Kemper, the Mac slaved to the 01V but now the 01V slaves to the KPA. Whenever the KPA unit is turned on, the 01V must be slaved or I have audio problems... if I turn the KPA off, I have to reset the computer and sometimes the 01V.

So I'm looking to slave the KPA unit to the 01V and my life would be much better; maybe the Behringer unit (thought it was a good suggestion but want to be sure before I spend the cash.. But I'm open to other suggestions if you've got them??

Quote from lightbox

Problem:
While recording you don't even notice if you forgot to sync the interface to the Profiler's S/PDIF Out (or sync is lost for some reason) ... because you only monitor the wet track for obvious reasons.
You only notice the pops and clicks when you try to actually use the DI track to reamp ... maybe a couple of days or even weeks after you've recorded.

This can potentially be a VERY expensive problem (if you need to re-record) or at least get you into some kind of trouble.

yup been there done that! I've even recorded two dry amp tracks instead of one DI, bummer too.. Now, I always listen to the SPDIF tracks before we start the active session just to be sure