Apogee Big Ben needed?

[Vincent]

Hi,

 

I was hoping for some advice, I am not to experienced with multiple outboard gear.

 

I'm currently using Focusrite's Liquid Channel Pre Amp running into Apogee's Rosetta 200, then SPDIF out of the Rosetta to the SPDIF input of an RME Hammerfal DSP Multiface II breakout box.

 

All three have a word clock connection, and I was wondering, (as I was told by someone) that if I had a master clock like the Apogee Big Ben, clocking all three units, it would really improve my audio recording quality.

 

Is this true? Is it necessary for only these three pieces, especially with the Apogee quality converters of the Rosetta?

 

If anyone has the Big Ben or knows of anyone who has one, would you please give me some advice and share your wisdom.

 

Much appreciated!

 

Thank You.

[MikeRivers]

I'm currently using Focusrite's Liquid Channel Pre Amp running into Apogee's Rosetta 200, then SPDIF out of the Rosetta to the SPDIF input of an RME Hammerfal DSP Multiface II breakout box.

Does everything work OK like that? Does it sound good? Do you get clicks in your recordings or playback?

I was told by someone that if I had a master clock like the Apogee Big Ben, clocking all three units, it would really improve my audio recording quality.

If you had clock synchronization problems, a master clock would solve them. If you're looking to make already good sounding gear sound better, it probably won't. But you really should make that decision yourself. Buy one, hook it up, spend a week or two using it, and if it doesn't make an improvement that you can hear, and that you care about, return it for a refund. Pro audio dealers know that people can't evaluate everything on paper or on line and actually have to try them in their system with their own program material and projects to see how they really work.

[amplayer]

I basically agree with what Mike said.

However, the system you describe is a bit intriguing. I would suggest considering all your routing scenarios and implications before plunking down any more money on hardware.

 

Are you running Analog to Analog I/O through the Liquid Channel?

From what I know of the Liquid Channel, this routing means the Liquid Channel converts the signal to digital, processes it, and then converts it back to analog. Thus, this system starts as an anolog mic level signal, gets converted to digital in the Liquid Channel and then back to analog, and then goes to the Rosetta to get converted back to digital again and sends it via SPDIF to your RME device. The RME device is only being used as a SPDIF input to your DAW (or other digital recording device).

I don't think this is an optimal way to use this system if I have stated your connections correctly. The main problem here, is that even though the RME has tons of I/O, it doesn't have the one connection you really need for use with the Liquid Channel: an AES digital input.

Basically, if you're happy with the Liquid Channel sound, you could replace both the Rosetta and the RME with a single one-channel AES digital input device!

[blue2blue]

There's much confusion on this.

 

As a general principal, syncing a given converter to an external source produces more jitter. (The internal clock, using a phase locked loop, must try continually adjust its own crystal-controlled clocking to match the incoming clock signal.)

 

A converter with a supposed "inferior clock" will actually have to work harder and probably be more greatly degraded by external clocking.

 

But if you have multiple units, you must have a single master clock, either one of the units, or from an external source.

 

In general, you will get the best results from a properly terminated daisy chain clocking arrangement. Because of the increased jitter issue, it is common to make the "best" converter the lead converter so that its internal timing will not be compromised. [i've corrected this but please see Mike Rivers' important notes regarding 'daisy chain' terminology below!]

 

In a large, complex rig (probably one considerably more compex than yours), one may find that a central clock source using a star topology is more convenient or easier to get relatively good clock to a large number of devices.

 

You may find it helpful to read converter design legend Dan Lavry's advice to someone with a somewhat more complex system than you have, explicating the issues (in his now archived PSW forum):

 

http://recforums.prosoundweb.com/index.php/t/10086/15450/

 

 

One side note for those who have bought into the notion that an external clock can somehow improve the timing accuracy of a single standalone converter: this is almost never the case.

 

There is the tech equivalent of an urban myth about this subject.

 

But Apogee themselves (who many feel have helped confuse the issue) will stipulate that external clocking tends to increase jitter inside a given converter. And, according to their marketing point man Max Gutnik, their official position is that those seeking to improve their converters would probably be better served by buying new (Apogee) converters:

For the record, we do not recommend buying Big Ben for the sole purpose of improving the percieved accuracy of your converter. Most often, the folks looking to do that, would benefit much more by just spending a little extra money and buying an Ensemble, or Rosetta 800. Clocking is just one aspect of what makes a converter sound good, so if you can improve the analog section, filtering and PSU as well as the clock, you are better off, even if the clock is not quite as good as the one in Big Ben (on the other hand, if you upgrade to the AD/DA-16X you get it all)...

http://www.gearslutz.com/board/so-much-gear-so-little-time/116635-good-clock-bad-clock-2.html#post1601641 [bold added]

 

Now, Apogee will argue that applying the clock from a Big Ben may make a unit subjectively "sound more accurate" -- even as they stipulate that the internal jitter will likely increase. But such subjective evaluations are not supported by objective measurement and, again, they are not claiming an increase in actual timing accuracy but rather they stipulate that internal timing accuracy of a given slaved unit will, indeed, likely go down.

 

They have a highly nuanced approach to this issue.

 

Now... if someone can explain to me just how this subjectively better sound despite decreased timing accuracy is somehow transmitted via the clock signal, I'd be amused to read it...

 

The ears-over-measurement guys have a field day with this one.

[MikeRivers]

[quote=blue2blue;24920795

In general, you will get the best results from a properly balanced/terminated daisy chain clocking arrangement. Other than an AES/EBU or optical data stream as a clock source, word clock connections are always carried on unbalanced lines, usually 75 ohm coax (RG-59).

 

Proper termination is important, however, and this is quite often a problem. Many devices have a built-in 75 ohm termination on the word clock input. This is proper if it's the only destination for the clock source, but when trying to distribute the clock "by wire," only the far end of the chain should be terminated. It's usually pretty easy to find the terminating resistor and remove it, but most people don't like to get into their gear with a soldering iron for fear of voiding the warranty. Some devices have a termination switch. That's handy.

 

ALso, you have to be careful about the meaning of "daisy-chaining." To some people, this means chaining by connectinng WC#1Out-WC#2In, WC#2Out-WC#3In, WC#3Out-WC#4In, etc. This is poor practice because each device generates its onw WCOut, so it will be delayed slightly from the incoming clock. Eventually things will get out of sync.

 

The way to use one device to clock several other devices is to put T adapters on the inputs wo WC#1Out goes to WC#2In, WC#3In, WC#4In . . . . with all terminations off except the end one. You can't predict how many devices you can connect this way, but you can pretty much be sure that if you try to connect two inputs with terminators on to an output, one or both devices won't work because the clock signal will be too low.

 

 

Apogee themselves (who many feel have helped confuse the issue) will stipulate that external clocking tends to increase jitter inside a given converter. Now, Apogee will argue that applying the clock from a Big Ben may make a unit subjectively "sound more accurate" -- even as they stipulate that the internal jitter will likely increase. But such subjective evaluations are not supported by objective measurement and, again, they are not claiming an increase in actual timing accuracy but rather they stipulate that internal timing accuracy of a given slaved unit will, indeed, likely go down. They have a highly nuanced approach to this issue.

 

Yes, it's called Marketspeak. They're happy to tell you that many people think things sound better (for whatever reason) when the Big Ben is used in place of a device's internal clock. That makes it mighty tempting since the goal is to make your system sound better, not specifically to have lower jitter.

 

Now... if someone can explain to me just how this subjectively better sound despite decreased timing accuracy is somehow transmitted via the clock signal, I'd be amused to read it...

I asked the same question of one of the more lucid Apogee engineers at an AES show a couple of years back. He suggested that there might be something in the shape of the jitter noise introduced by their clock (no doubt a deep Apogee secret) that makes the timing distortion less correlated with the audio. I dunno.

 

The guy from Antelope Audio (who also makes a fancy master clock generator) insisted that connecting it to anything would make it sound better. And that by adding his $6,000 optional rubidium frequency standard to clock the clock, it would sound better still.

 

There will always be things that will make audio sound subjectively better, but at some point, the practical person has to say "it's good enough for me" and get to work. On the other hand, god created audiophiles so developers would have someone to whom they can sell their solutions.

[blue2blue]

Thanks for your corrections, Mike... I apparently somehow misquoted Lavry in my own notes on this (with regard to the concatenated phrase "balanced/terminated" -- but I don't find the reference in his forum I thought I'd based it on -- I've corrected my post above to avoid even momentary confusion).

 

I used the term daisy-chain because that's what Lavry used -- but I believe your qualified description is similar or identical to what he recommends.

 

I defer to your corrections.