Are there audible differences between different DAC and ADCs?

[Dolmetscher007]

My 1st gen USB Focusrite 18i8 has been great! It seems to be dying a slow death, however. Tons of hardware issues that have just gotten worse and worse. It's time for a new interface.

It makes me feel bougie and posh to say it, but I have a much more robust budget these days, and I want the highest quality audio capturing I can find/afford. My I/O needs are super simple. I don't record drum kits or anything requiring more than two simultaneous mono signals. I do record guitar with a dual mono, DI + mic'ed amp, scenario. Therefore, all I am really interested in is audio fidelity. I have seen companies like RME that sell outboard gear that is labeled as just "Analog to Digital Converters", as well as the reverse "DAC's". They cost upwards of $3.5k, which tells me, it had better be one kick-ass uni-tasker! But then again, they handle something like 32-channels of ADC input.

To get to the point, has there been anything written in the past few years about what to look for in a super high-quality interface as far as ADCs audio capturing is concerned?

[Sam Spoons]

How good is your room? If it's as good as, say, Abbey Road then how good are your monitors? And, so on.....

This is often discussed on here and the usual conclusion is that the AD/DA converters are way down the list of things that will compromise your recordings.

[shufflebeat]

My next purchase will probably be the SSL2+ of we make it past summer. It'll be a while before I outgrow that.

[Eddy Deegan]

How good is your room? If it's as good as, say, Abbey Road then how good are your monitors? And, so on.....

This is often discussed on here and the usual conclusion is that the AD/DA converters are way down the list of things that will compromise your recordings.

Indeed. My impression is that you need to spend £30k on treatment and monitors in order to be able to tell the difference between an interface costing £600 and one costing £3000, assuming your ears are capable of it in any case.

I generalise, and pulled those figures out of a metaphorical hat but you get the idea. Buy a quality bit of kit that has the I/O and features that you need, and that's had a good SOS review and/or a personal recommendation from a few folks here and you'll not go wrong.

[Hugh Robjohns]

A 30k room treatment budget would be nice, Eddy, but unless you live next to a railway line /airport /motorway/ rave site / hammer forge... you can probably convert a typical domestic spare room into a pretty decent listening space for 5k with commercial acoustic products, and a lot less for DIY panels.

But certainly the principle is sound (excuse the pun) because the differences, even between the extremes of converter standards, is very small indeed.

But if the OP's stack of cash is burning holes in his trousers, the very best interface I have measured and audtioned to date is the RME ADI-2 Pro.

https://www.soundonsound.com/reviews/rme-adi-2-pro

However, it is a straight 2-channel AD/DA with USB connectivity, so only provides line levels in and out. You would need a separate mic preamp with DI inputs for recording you guitars and amps etc. ... But then if the budget is good that won be an issue and allows a choice of preamp based on personal preferences.

For an all-in one solution, you could look at the Prism Audio Lyra 2. The tech specs don't appear as good as the RME, but it sounds very nice indeed.

https://www.soundonsound.com/reviews/prism-sound-lyra-2

...but bear in mind that if you gather a dozen soundies in a pub and ask for interface recommendations, you'll get a dozen answers...

[resistorman]

OK then. I’m curious too. If you take take the room acoustics completely out of it by using a direct input from a top quality source and listen on top quality headphones, is there an audible difference between converters these days? Adjacent to that query, is there much of a penalty going through a series of conversions like D/A-A/D-D/A with modern equipment and sensible settings?

[Tim Gillett]

OK then. I’m curious too. If you take take the room acoustics completely out of it by using a direct input from a top quality source and listen on top quality headphones, is there an audible difference between converters these days? Adjacent to that query, is there much of a penalty going through a series of conversions like D/A-A/D-D/A with modern equipment and sensible settings?

This may be relevant:

https://ethanwiner.com/loop-back.htm

Tim.

[ef37a]

OK then. I’m curious too. If you take take the room acoustics completely out of it by using a direct input from a top quality source and listen on top quality headphones, is there an audible difference between converters these days? Adjacent to that query, is there much of a penalty going through a series of conversions like D/A-A/D-D/A with modern equipment and sensible settings?

Ah but then, which are the 'best' most accurate headphones around? You would also need a 'perfect' headphone amplifier and switching system to do the deed! The general opinion as well is that open backed cans are the most accurate but in that case are they TOTALLY immune from room effects and ambient noise? We are after all dealing with tiny, tiny super subtle differences here.

That RME looks the top bet since it has ADAT expansion so OP could hire in a pre amp rig should the need arise.

Dave.

[Aled Hughes]

I’m very happy with my RME Babyface Pro.
The newer FS model should offer slight improvements as well.

[Arpangel]

For an all-in one solution, you could look at the Prism Audio Lyra 2. The tech specs don't appear as good as the RME, but it sounds very nice indeed.

https://www.soundonsound.com/reviews/prism-sound-lyra-2

...but bear in mind that if you gather a dozen soundies in a pub and ask for interface recommendations, you'll get a dozen answers...

Interfaces can sound different, but the differences are subtle, unless you’ve got very good monitoring in an excellent room.
Prism would be my choice, but as has been said, opinions differ.
Focusrite for me have always been a good choice at a reasonable price.

[CS70]

To get to the point, has there been anything written in the past few years about what to look for in a super high-quality interface as far as ADCs audio capturing is concerned?

In an ideal world, all D/A and A/D converters do the same job the same way with the same (perfect) results. In the real world, as usual, is not so: concrete realizations of the ideal device differ from the ideal and allow them to go "wrong" and produce "errors", which ultimately affect the sound.

Possible "errors" can be timing errors in clocking (often due to mundane things as changes in temperature of the surrounding environment), recognition of the exact threshold between adjacent ranges of voltage, difficulty in creating circuitry that behaves in a perfect linear way over a large range of values, and so on.

Different conversion methods and corresponding techs also have different pro and cons, even if - without having used first hand too many boxes - it seems that sigma-delta conversion is the method of choice nowadays.

Since there are quite a few parameters that can be tweaked and design decisions to taken and components to be chosen (against a price point), that means there's a lot of combinations of design and manufacturing choices leading to slightly different results.

However the keyword here is "slightly". In all practical design all these "errors" tend to very, very small: given to the very nature of conversion, anything major would have such catastrophic effects on the sound that it would be unusable. So even the worst converters don't really go wrong much, so long they work.

That's why you can do tests like looping a signal thru thousands conversion cycles and not hearing any degradation. The errors are there, and they are accumulating and therefore degrading the signal... but the degradation stays pretty insignificant unless you reach hundred of thousands or millions of cycles or even more. Which obviously never happens at least in music-making applications. For the same reason, when exactly you'll be hearing things depend on your specific, biological sensitivity.

What usually matters most in A/D is the circuitry that prepares the (still analogue) signal for conversion, cleaning it up, changing the amplitude, splitting it etc etc in the various way a specific conversion method may need. That's probably the difference you can hear most - it's another analogue stage before your actual converter chip.

Since that stage is there to "massage" the signal within well known, design-fixed and not user-controllable parameters, it tends to be quite alright in all converters.

But in the analogue world differences in component quality, design choices etc may make, as usual, a quite audible (and price!) difference, and there you are!

So yes, there surely are differences between different converters, but they tend to be mostly due to the pre or post analogue stages rather than the converter itself and they are usually small.

[ef37a]

CS70 can you give some more in depth detail of these (naughty!) pre and post converter analogue stages?

My admittedly limited, reading of the subject tells me that these stages are often the ubiquitous NE5532 op amps and at the near unity gain usage employed their distortion levels are close to be best test gear available. Better devices are now available but better than 0.001% at 10kHz is gilding the daffodil?

Maybe what is detected (if at all) is component tolerances? A capacitor in a filter might give a response 0.1dB up or down compared to one in another device but neither device is 'wrong'.

Dave.

[John Willett]

...but bear in mind that if you gather a dozen soundies in a pub and ask for interface recommendations, you'll get a dozen answers...

Only a dozen?????

[ef37a]

...but bear in mind that if you gather a dozen soundies in a pub and ask for interface recommendations, you'll get a dozen answers...

Only a dozen?????

Yeah, at least a Baker's!

Dave.

[CS70]

CS70 can you give some more in depth detail of these (naughty!) pre and post converter analogue stages?

Dont think it makes sense here for the same reason for which I didn't really write anything on how converters work: even a long and boring text wouldn't begin to cover what needs to be covered, and there's lots of papers easy to find online. Just google "analogue front end ad converter" and you'll find plenty info at any level.

[Hugh Robjohns]

If you take take the room acoustics completely out of it by using a direct input from a top quality source and listen on top quality headphones, is there an audible difference between converters these days?

Measurable differences? Yes... but mostly very small.

Audible differences? Yes, but mostly due to the analogue circuitry rather than the conversion itself. So it's much like comparing preamps or monitor controllers.... Very, very subtle and usually totally and utterly irrelevant in any practical sense.

Adjacent to that query, is there much of a penalty going through a series of conversions like D/A-A/D-D/A with modern equipment and sensible settings?

In the mid-90s a colleague and I recorded a selection of test material onto a professional Sony DAT recorder, and then connected the machine to a second of the same type via balanced analogue interconnects. We carefully matched recording levels and then bounced the audio from one machine to the other and back again 50 times.

Naturally, there _is_ some degradation, and in a direct comparison of take 50 with take 1 it is quite obvious... but most 'ordinary' (ie, not trained audio pros) people listening to take 50 in isolation probably wouldn't notice it at all. Skilled listeners can start to hear artefacts after 10 generations, but I've not found anyone who can reliably hear any differences after less than ten generations.

And that was with what is now 30 year-old converter technology. Things have improved further since then...

So the answer is no, there is no practical penalty at all. And many mastering houses do exactly that all day long...

[resistorman]

Thanks! Very interesting. I developed the habit of worrying about multigenerational sound degradation back in the analog days and have carried it well into the digital age.

[Hugh Robjohns]

If you connect digitally, there are no multi-generational losses, of course.

But even back in the analogue era, the damage was mostly done by the tape. Extensive chains of electronic equipment suffered very little quality loss if done well. Just ask any broadcaster!

Most mastering houses combine long chains of both analogue and digital processing gear, with lots of format conversions in between. My mastering activities are very small scale, but if the source is analogue tape I routinely go through three or four conversion stages (including the final monitoring D-A), but it I have had six before now!

[ef37a]

If you connect digitally, there are no multi-generational losses, of course.

But even back in the analogue era, the damage was mostly done by the tape. Extensive chains of electronic equipment suffered very little quality loss if done well. Just ask any broadcaster!

Most mastering houses combine long chains of both analogue and digital processing gear, with lots of format conversions in between. My mastering activities are very small scale, but if the source is analogue tape I routinely go through three or four conversion stages (including the final monitoring D-A), but it I have had six before now!

Indeed! I am old enough to remember Acoustical's advert with multiple 303s with attenuation in between.

Since that time analogue amplification has been beyond reproach IF it is done properly!

Dave.

[cyrano.mac]

Don't worry about audible differences between ADDA's.

Look at driver stability. Most manufacturers don't even roll their own. That means if you buy an interface that isn't popular, you won't get updates, sending your investment to the junk pile.