Turtlerock Forum

so basically this will be my signal chain

preamp - converter - fw in/out - converter -

i want to maintain the integrity of the sound with the best possible conversion at either end

so am i better off with an ad da converter with built in firewire(apogee rosetta with xfw),, keep in mind i dont need something with pre amps as i already have an outboard analogue pre.

or

am i able to wire it up so that i can get good stand alone converters (lavry, mytek etc) and a cheapie firewire interface (ala mackie, digidesign 003etc) and connect them via spdif/adat without loosing quality/information. if i wire up the convertors via spdif/adat does that mean im essentially bypassing the conversion process of the shitty soundcard....(i cant afford a good soundcard and converters)

im wanting to run with the later as there is more flexibility for what im needing but unsure if the extra connections required do anything to change the sound and render my good converters useless.

You have a couple of things to consider.

Lets work backwards from the DAW to the preamp.

You have your choice of DAW software, running on your PC or Mac of choice.

You have to have some sort of interface, you have spec'd FW.

Probably the most critical thing to get right, is the marrying of the Firewire audio interface to the Computer itself.

Stability, Latency, and usually, amount of I/O is what is critical here.

This can be a minefield. Depending on your type of computer (mac/pc...home built PC, a PC built by a specialist audio pc maker) it can have conflicts between the firewire controller on the PC and the audio interfaces firewire connection.

You will hear words like Dice, JetPLL, Texas instruments etc.


By the way you asked your question, I am gathering that you might not have a great handle on this. I apologise if I got that wrong.

Also, you might be surprised by the difference between things like Mytek, Lavry, Apogee and the converters that come standard with a FW interface. It depends on what you are recording, the environment you are recording in and the monitoring system you are listening on, and the level of experience you might have.

Basically, you need to go with a FW interface that you know works, at latencies you are happy with, in conjunction and harmony, with the computer you are going to use. Thats the single most important thing.

Lets assume you have that and you got something like an RME interface, say a UCX, its hanging off an iMac. Via its FW connection (the UCX also does USB).

You now want to use an external converter. You usually can connect it via a few ways, analog, spdif, adat, AES.


Which ever way you do it, when you have two or more devices, that are A/D converters connected to each other, one has to be Master Clock, and one has to be SLAVE.

There is a massive amount of debate on the benefits of external clocks.

I suggest, work out what interface you want first. Work out your Budget. Get a good, stable, FW interface...and then decide on whether you are unhappy with its AD/DA conversion.

cheers

Thanks for the reply Peter. I think that you have missed the part of my question I wanted to know most about, probably due to my phrasing.

I understand clocking latency etc I'm just wondering that if I use a standalone converter to convert my preamps signal then wire it into, for arguments sake, a digi003 via spdif am I going to loose anything as opposed to if the same converter had an onboard fw interface and was wired directly into my comp?

Does routing the signal via spdif or adat bypass the conversion process in the interface as it already is a digital signal and the same thing d to a?

uglytaco wrote:Thanks for the reply Peter. I think that you have missed the part of my question I wanted to know most about, probably due to my phrasing.

I understand clocking latency etc I'm just wondering that if I use a standalone converter to convert my preamps signal then wire it into, for arguments sake, a digi003 via spdif am I going to loose anything as opposed to if the same converter had an onboard fw interface and was wired directly into my comp?

Does routing the signal via spdif or adat bypass the conversion process in the interface as it already is a digital signal and the same thing d to a?

When you connect two digital devices together, both devices have clocks, and those clocks must be synced.

One device has to be Master, the other slave.

Some devices perform differently when they are slaved than when they are the Master clock source.

This can cause differences in the sound of that unit. How much? How bad or good? These things are personal preference.

so the answer is, yes, no , maybe.

You might pick up the sound change, you might not. You may like it. You may not.

The difference might be worth the money.

As I said, get the most stable, FW interface for your computer. Listen to your preamp through that interface. If you like it you are set. If not, then, try external A/D and D/A converters.

But its going to be subjective.


To answer your direct question.

Yes. Inputting into the FW interface, via spdif from an external converter, bypasses the interfaces A/D stage...BUT....one of the devices, is not being driven by its own clock, it is locking to the other.

Does that make sense?

Yes, it's already 1's and 0's so there will be no problems and no degradation.

If you're worried about possible effects of clocking, just make the good quality box (Mytek etc) the master.

cheers for the advice guys.

as i said clocking wasn't my concern as ive used myteks before and really like them. in the hypothetical case of the mytek through the 003 the mytek would obviously be the master. i was just unsure of what happened to the digital signal once it passes through the 003 and onto the computer. It makes sense that once digital it stays digital i just needed confirmation in case there was something i was missing.

So Allistair once signal has been converted to digital there is no chance of sound change/degradation? losses of 1's and 0's along the line at some point?

Digital is binary, so you can't really lose "10% of high end sparkle 1s and 0s".
Any problems will show up as clicks, pops and drop outs, not as changed frequency response.
I've seen this due to crappy cables or unmatched clocks, but I would never think the internal path in a converter would introduce it.

Alistair wrote:Digital is binary, so you can't really lose "10% of high end sparkle 1s and 0s".
Any problems will show up as clicks, pops and drop outs, not as changed frequency response.
I've seen this due to crappy cables or unmatched clocks, but I would never think the internal path in a converter would introduce it.

jitter?

Ok, sure. I'll edit it to-

"In a theoretical world, there is a possibility of getting interference with our digital signal anywhere in the chain. In the real world, I've personally never seen digital signals receiving audible interference from anything apart from poor quality cables and clocking issues."

To quote Wez from the thread sitting just below this one-

"If you're not sure you need to worry about it then you don't need to worry about it.

If you are worried about how to know if you need to worry about it, then you don't need to worry about it. you will know when you need to worry about it.

If you know enough to know when to worry about it, you will stop worrying.

If you're not worried about it, then congratulations - you have reached nirvana."


If I was Robert, I'd plug my Mytek into my Digi 003 (or whatever the units are), set the Mytek to master and the Digi to slave, and be 100% confident I was getting the signal that Mr Mytek intended for me to get.

fair enough Alistar...if it sounds good ...it is good..

well to sort this out the way i read it

untill very recently i have been running out of a 002 spdif into the (umm reassuringly expensive)
weiss maya converters

so if the question is fw to interface via spif into the best converter on the planet
yes all good

latency.. no no good at all but no issue in my needs

the weiss maya has firewire of coarse but protools didnt use to talk to it

unfortunately
due to world of stuff i am in the weiss maya has not made it into the new studio setup ..
just cannot afford to keep things i cannot afford any longer

first session in the new place on the 20th of this month !
then its truely onwards and upwards

rick wrote:unfortunately
due to world of stuff i am in the weiss maya has not made it into the new studio setup ..
just cannot afford to keep things i cannot afford any longer

Aah, that's a real shame Rick. The Weiss was nice, pardon the pun.

Didn't you have 2 Maya's when I was there at the Camperdown studio?

What are you using for conversion now?

still running weiss converters , but i couldnt afford to be divorced and keep the big uber one