Digital to Analog Conversion (R-2R DAC) & Analog Mastering

[silent_bob]

Hello all,

Long time visitor, first time poster. I'm hoping for some advice/recommendations.

I have an album awaiting release that was produced/recorded inside of Ableton at 44.1k, 24 bits. I am hellbent on obtaining the best possible masters (within a reasonable price range). I've become increasingly interested in analog processing.

If I understand correctly, I will need to run each song through a specific digital-to-analog converter designed for this purpose (a ladder DAC?), and then into the analog compressor/limiter (I'm thinking of using the WA76 based on the classic 1176). Then either back into the computer on a new track, or preferably straight onto magnetic tape.

Do any of you have experience with this? Does the above sound correct? Do you have any gear recommendations that aren't ridiculously overpriced for a good DAC? The tape recorder?

If I were to just rerecord the processed audio back into the digital environment, what settings should I use to retain quality? Or should I stick with the native settings? I currently use a Saffire Pro 40 interface. Its' max settings are 24 bits at 96k (but I have been working in 24 bit 44.1k to keep consistent, on account of samples I'm using and lack of processing power). Should I avoid using it altogether, post-processing? Should I upgrade it with the Black Lion Audio mod, or buy something else?

I apologize for all of the questions, but I sincerely appreciate any info you have for me. I've put over a year and a half into this project, and have barely slept. It's finally nearing completion, but I've hit a wall with this. Thank you everyone!!

 

[vinyldavid]

Well, hello!

I do a fair bit of live recording, a small amount of studio recording, and a decent amount of live mixing.

I also have over 20 tape machines, up to an including MCI, Otari, Ampex, 3M, Scully, etc.

It's my belief that NOTHING should need "mastering". Mastering was necessary to take a studio tape and cut it to vinyl, but when you release medium is most likely digital, there's no such need to process the material after mixing. You don't need to compress it to keep the stylus from skipping, or cut the high and low end so cheap players can track it. Export your final mixes as 16/44.1 and deliver them to the duplicator. Export your 24/44.1 mixes and archive them on 5 different things (HDD, HDD, DVD, DVD, Flash), and you should be okay. Today, mastering engineers "fix" things that IMO should have been done in the mix phase, because so many people have access to recording equipment, not just people who know what they're doing. Also, people who don't know how to compensate for issues in their monitoring can often create mixes that need to be tweaked.

If you do want to have your project "mastered", a quick google search will reveal people who can master in both digital and analog formats, it's definitely NOT a do it yourself project. I think I know quite a bit about audio, and I wouldn't dare try to pass myself off as any sort of mastering engineer. There's so much more to modern mastering than just a good compressor and tape machine.

One place where I see a possibility to improve is having the final mixes summed in analog (and then possibly record that to a nice tape recorder), using a regular mixer or dedicated summing box. Many people have found that analog summing helps improve the cohesion and clarity of their mixes, as opposed to using whatever summing algorithm that your DAW has. Recording the output of the summing mixer to analog will yield the most direct master route, but I would also record the output back to digital on a different computer. You'll need as many channels of DAC as you have channels on mixdown. The ADC and DAC's in the Focusrite Saffire Pro 40 are excellent, I use a Liquid Saffire 56 myself, and am very happy with it overall. In fact, I'm looking into getting a pair of Pro40's to lightpipe in and out more inputs early next year.

There's no such thing as a DAC designed for outputting to tape (that I'm aware of, anyway).

Basically, make the mix sound good and don't worry about getting a good master. The best master is the one that doesn't need any work. Get it right in the mix stage and you're done.

 

[silent_bob]

Thank you for your reply.

"have the final mixes summed in analog (and then possibly record that to a nice tape recorder), using a regular mixer or dedicated summing box."

This sounds more like what I was thinking. The tracks themselves need very little in terms of 'mastering.' More or less they just need minor gain reduction at the limiter to bring everything a little closer to the ceiling. And I'm looking to add some authentic analogue warmth in the process.

"You'll need as many channels of DAC as you have channels on mixdown."

Could you elaborate a bit? A few of my songs are composed of many, many audio & MIDI tracks. I couldn't imagine sending each one individually through the DAC. In this case, would I just mix certain tracks together into one channel (ie combine all of the vocal stacks into one) to reduce the overall number of channels? Or could I simply send the left and right channels from Ableton's master track through the DAC?

"There's no such thing as a DAC designed for outputting to tape (that I'm aware of, anyway).."

I just meant that there are DACs specifically designed for end-listener playback (ie when listening to an iPod with headphones), and then there are DACs designed for analog signal processing ("mastering grade"). I'm interested in something like the Crane Song HEDD or the Forssell MADA-2, but am curious how they compare to the D/A converter in the Saffire Pro 40. Is the $4,000 price tag warranted in this case? Would my money be better spent just paying $495 for the Black Lion Audio mod to the Saffire, or should I upgrade from the Saffire altogether?

Perhaps I could simplify my prior post:

"My album is done. What should I do now to ensure the *best quality master without selling a kidney? Something tells me that just using Ableton's limiter, and rendering with POW-R3 (to dither from 24 to 16 bit), isn't going to yield as good of a result compared to analog processing, and making the album copies straight from an analog master."

Thanks again for any and all information you can provide.

 

[vinyldavid]

"Could you elaborate a bit? A few of my songs are composed of many, many audio & MIDI tracks. I couldn't imagine sending each one individually through the DAC. In this case, would I just mix certain tracks together into one channel (ie combine all of the vocal stacks into one) to reduce the overall number of channels? Or could I simply send the left and right channels from Ableton's master track through the DAC?"

Yes. You send each track through a DAC simultaneously, and use a real mixing desk to put the tracks together. That's the whole point of analog summing-NOT to mix anything together in digital, bypassing that bussing algorithm completely. Some people do mix together certain tracks down to stereo stems (like drums), but once you start doing that as a habit with each part of the song, you start to lose some of the advantages of analog summing. A quick google search will tell you far more about it than I have time to go into here.

"I just meant that there are DACs specifically designed for end-listener playback (ie when listening to an iPod with headphones), and then there are DACs designed for analog signal processing ("mastering grade"). I'm interested in something like the Crane Song HEDD or the Forssell MADA-2, but am curious how they compare to the D/A converter in the Saffire Pro 40. Is the $4,000 price tag warranted in this case? Would my money be better spent just paying $495 for the Black Lion Audio mod to the Saffire, or should I upgrade from the Saffire altogether?"

The most accurate way to capture the mix from Ableton is to export a 24/44.1 file of the mix "in the box", it will never be more accurate than that. Back that file up, and that's your master. Run that through a good DAC and record to take and there's your tape master. Find someone with a good working 2 track deck and buy a couple reels of RMGI SM900. Record it, wait 24 hours, and then dump it back to digital. A/B the two files and see which you like better. Pick the one you like the best.

Overall, what I'd recommend is getting the song to work the way you want it, making the file sound the way you want it, and then printing all the multitrack files back out to an individual .wav file PER CHANNEL. Then, take that to your helpful local recording studio and see if anyone around can use their desk to mix the files down to stereo in an analog mixer, with whatever compression you want to use, and record that output back to digital and tape simultaneously.

Using a better DAC to create your master is a great idea, but as I said above, mastering is not a "DIY" endeavor. Having an amazing DAC like the Crane Song or Forssell is a good thing, but don't expect that piece of gear to totally change the sound of your album. You may hear more details, but that's about it. Focusrite gear seems to be fundamentally accurate (if a bit cold-sounding), and I'd trust what comes out of its' TRS jacks as an accurate analog representation of what is in the digital signal. That's what a DAC should do. Modding your Focusrite when you could buy another for that cost seems silly to me-the added benefit of having more ADC's and DAC's available would outweigh the sleight (most likely imperceptible) sonic increases of a Black Lion Audio mod to anything from Focusrite. It's not like we're talking about the Behringer ADA-8000-that most likely would really benefit from having BLA go through it (to use an example of something popular that they worked on in the past).

What do you use for monitoring? Do you *know* what your room sounds like? Have you run tones? Those are usually the first things I address if someone wants to seriously mix in a space.

Edit: Also: Why do you NEED a limiter or a compressor? Just because a lot of people put a compressor on their 2mix doesn't mean you have to...