Analogue console +26 dBu mix out into +19 dBu or +26 dBu converter input?

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Analogue console +26 dBu mix out into +19 dBu or +26 dBu converter input?

Post by cashhewn »

Hello folks,

I'm using a Soundcraft 600 to mix and output final stereo mixes, and this console is capable of +26 dBu at the mix bus output.

I have typically been converting final mixes out of the analogue console mix bus to digital via an RME ADI 2-FS, which has an input capability of +19 dBu. However I also have a Focusrite Clarett 8pre, which has an input capability of +26 dBu.

I'm wondering what the considerations are when weighing whether one of these devices is more advantageous than the other for this purpose of capturing a final mix?

I've experienced that the RME clips more easily with its +19 dBu input, but I simply back off the console master fader a few dB until the converter stays below clipping and then capture the track in the DAW. Beyond this, I'm not sure which of the converters is "better". I don't hear much of an appreciable difference when A/B-ing these digital captures via their respective converters back into the console's monitoring section. Maybe it doesn't matter, ha!

Also, kind of related yet tangental: @hughrobjohns re: your article on a different RME device in the July 2021 volume 36 issue 9, where does (or doesn't) the ADI-2FS sit on your top ten A/D D/A list? (and how do you ever have any time at your Crookwood to do mastering work if you answer questions like these all day?!)

Maybe it's splitting hairs but I am curious what the considerations might be in choosing one or the other of these devices as the superior A/D converter for my final mixes.

Thanks for your help!
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Re: Analogue console +26 dBu mix out into +19 dBu or +26 dBu converter input?

Post by ef37a »

Before the Doc' wades in...Given the choice I would always go for an RME interface for all the reasons mentioned here many times.

I would make up an attenuator box to fix the level difference. I did this years ago feeding an A&H ZED10 into a Delta 2496.

Dave.
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Re: Analogue console +26 dBu mix out into +19 dBu or +26 dBu converter input?

Post by Hugh Robjohns »

Tackling the simple questions first,

cashhewn wrote: Sun Oct 10, 2021 4:13 am ...where does (or doesn't) the ADI-2FS sit on your top ten A/D D/A list?

I haven't tested it, but it is supposed to use the same converters, technologies and overall design topologies as the ADi-2 Pro, so I'd expect it to have a similar performance. That would probably make it around 121dB (A) AES17 dynamic range for the D-A, and maybe 122dB (A) or more for the A-D. Reasoned guesswork, but I'd be surprised if it wasn't in that area -- really bloomin' good, in other words, and a few decibels better than the Clarett (which is also very good).

...how do you ever have any time at your Crookwood to do mastering work if you answer questions like these all day?!)

I use the Crookwood every day -- it's the heart of my studio set up and everything goes through it. Mastering is only an occasional fun distraction for me, to help a few special clients. It's not my main source of income.

I'm using a Soundcraft 600 to mix and output final stereo mixes, and this console is capable of +26 dBu at the mix bus output.

First thing to remember: being capable of it doesn't mean you have to use it. My car's supposedly capable of 155mph, but I've never felt the need to test it! ;-)

I'm wondering what the considerations are when weighing whether one of these devices is more advantageous than the other for this purpose of capturing a final mix?

I'd just go with whichever is the more convenient, easiest to use, and you prefer the sound of.

While it's true that the Clarett won't clip until the desk does, I don't think that is relevant in a practical application. Are you really pushing your desk so hard hard that you routinely have peaks at +26dBu? And if so, why? Most desks sound pretty rough when you're nearing clipping, and the Soundcraft 600 is nothing special from a circuitry point of view... (I installed and commissioned a 600 desk in a BBC dubbing theatre in the late 1980s.) Added to which the whole idea of headroom is so that your audio stays well away from the nasty region!

RME chose a +19dBu maximum input level because that gives 1dB of extra headroom above the European broadcast standard maximum operating level. (Some of their later designs now have a +24dBu option to keep the Americans happy!)

But if broadcast sound engineers can control their mixes to stay below +18dBu I'm sure you can too. Most of my gear here can handle +24dBu or more, but I still work with a notional 18dBu maximum analogue level and have no issues with it.

What I would say is that if you genuinely are creating peaks over +19dBu that overload the RME you're either mixing way too hot through the desk, or you have some pretty wild and uncontrolled transients kicking around in your mixes that might benefit from a little more dynamic control on the channels or groups.

I've experienced that the RME clips more easily with its +19 dBu input, but I simply back off the console master fader a few dB until the converter stays below clipping and then capture the track in the DAW.

Good plan as a quick fix... and pulling the main fader back by a few dB isn't the end of the world, but it would be better as you build the mix with the channel and group faders to make sure you don't get too hot, rather than compromise the output gain staging and SNR.

Beyond this, I'm not sure which of the converters is "better". I don't hear much of an appreciable difference when A/B-ing these digital captures via their respective converters back into the console's monitoring section. Maybe it doesn't matter, ha!

To be honest, with a choice of converters that are both so good it really doesn't matter, as the differences are so small and largely irrelevant.
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Re: Analogue console +26 dBu mix out into +19 dBu or +26 dBu converter input?

Post by Terrible.dee »

cashhewn wrote: Sun Oct 10, 2021 4:13 am Hello folks,

I'm using a Soundcraft 600 to mix and output final stereo mixes, and this console is capable of +26 dBu at the mix bus output.

I have typically been converting final mixes out of the analogue console mix bus to digital via an RME ADI 2-FS, which has an input capability of +19 dBu. However I also have a Focusrite Clarett 8pre, which has an input capability of +26 dBu.

I'm wondering what the considerations are when weighing whether one of these devices is more advantageous than the other for this purpose of capturing a final mix?

I've experienced that the RME clips more easily with its +19 dBu input, but I simply back off the console master fader a few dB until the converter stays below clipping and then capture the track in the DAW. Beyond this, I'm not sure which of the converters is "better". I don't hear much of an appreciable difference when A/B-ing these digital captures via their respective converters back into the console's monitoring section. Maybe it doesn't matter, ha!

Also, kind of related yet tangental: @hughrobjohns re: your article on a different RME device in the July 2021 volume 36 issue 9, where does (or doesn't) the ADI-2FS sit on your top ten A/D D/A list? (and how do you ever have any time at your Crookwood to do mastering work if you answer questions like these all day?!)

Maybe it's splitting hairs but I am curious what the considerations might be in choosing one or the other of these devices as the superior A/D converter for my final mixes.

Thanks for your help!

Does your master fader have a "gain range" metered in print next to the fader?

That is to say, that if their are lines with numbers next to them next to the fader, there may be one area, probably about 75% of the way up, where the line will double in density.

That is the recommended operating level for that particular piece of gear.

Use which ever one lets you sit in that range.

Or the other method is this....

....What sounds good to YOU?

Use THAT one.
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Re: Analogue console +26 dBu mix out into +19 dBu or +26 dBu converter input?

Post by cashhewn »

Thanks for the helpful responses.

@ef37a I agree and love my RME, the ADI-2FS, as it's a fantastically useful device in the studio and does so many helpful things. And clever idea with the attenuator box!

@hughrobjohns Very good point asking why I am seeing levels approaching +26 dBu at the mix bus. I'm still new to all of this and I reckon that it's the transients of the snare or kick drum most likely. I don't believe that the main mix levels are absurdly high, I usually try to stay with those RMS needles hovering around 0 VU, but I do see the red "peak" LEDs blink sometimes and it's probably those moments I suppose that are clipping the RME's +19 dBu input. I will continue to experiment with both pulling levels down on the individual channels, as well as continuing to experiment with individual track compression and limiting. Until I have more experience I have been trying to avoid a master bus limiter (however I just received a Heritage Audio HA-609a [33609-style compressor/limiter]), and I suppose that this might be the exact application for such a device! Thanks for your help as always.

@terrible.dee Thanks for the suggestion, the console has a "full length liner fader" on the master and the markings are evenly stepped from +10 down to -40, where they become double density from -40 on down to infinity. I'm thinking I'm going to continue to use the RME as the mix bus converter and be more judicious with the individual track levels feeding the mix bus, and also try to use compression or limiting on things to keep the master fader at unity yet avoid clipping the RME input. I'm new to this still, but having fun making music and experimenting!
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