Print back through preamps?

[wearashirt]

Hi everyone, I do hybrid mixing i.e. send individual tracks through multiple line outs and route the master bus from the analog mixer back into the interface for the so called "print".

My question is, is it advisable to do the print-back via an audio interface whose line-ins are "padded through the mic preamps"? Or should I find an interface that has line-ins that do not pass through the preamps?

I'm referring to the Audient ID14 mk2, whose preamps and line inputs have been tested to have flat frequency responses. But will I still get some undesirable coloration when it comes to passing through a master mix?

In the past, I've been printing back through the Behringer UMC1820's inputs. I can easily compare the analog mixer's headphone out v.s. the behringer post-converter result, and indeed I'm losing some mojo with the print-back. (It's likely that the Behringer's line ins also pass through the preamp. Not sure if that matters). Hence, I've been looking for an upgrade. Sadly, many competing audio interface brands are low on stock at this time of the year.

[Hugh Robjohns]

Most interfaces with mic/line inputs will pad the line input down and route it through the mic preamp. Some will also curtail the preamp gain range in line mode.

In most cases the noise and distortion introduced by this attenuation+gain approach is negligible. Given the cost savings of avoiding a separate line input stage, the compromise is a fair one which is widely employed even in some quite high-end products.

The Audient preamps are known for being clean, so I doubt you'll have any problems.

But if you're after ultimate quality, I'd look for a good two-channel A-D with line inputs and an S/PDIF output that you can plug into your interface, bypassing the interface's analogue electronics completely.

[Wonks]

What is the mixer you are using? How do you know it's not the headphone output on the mixer vs the headphone output on the Behringer that's providing the difference in sound? You may get a very similar result with a new interface, when in reality the audio signal itself remains unchanged.

I'm not saying there isn't a difference, but just want to point out that the sonic difference you hear may not be down to the audio interface's inputs.

[James Perrett]

I use the line inputs on my Audient ASP008 more than the mic inputs with no issues when it comes to sound degradation. This uses the same preamp design as your iD14.

If you are really worried about this you could use an Audient ASP880 connected to the optical input of the iD14 which has dedicated inputs that go pretty much direct to the ADC.

[wearashirt]

But if you're after ultimate quality, I'd look for a good two-channel A-D with line inputs and an S/PDIF output that you can plug into your interface, bypassing the interface's analogue electronics completely.

Any particular products in mind?

(Wouldn't it be counter intuitive for a product to already have the signal converted , but still not have a USB connection?)

[wearashirt]

What is the mixer you are using? How do you know it's not the headphone output on the mixer vs the headphone output on the Behringer that's providing the difference in sound? You may get a very similar result with a new interface, when in reality the audio signal itself remains unchanged.

I'm not saying there isn't a difference, but just want to point out that the sonic difference you hear may not be down to the audio interface's inputs.

It's a 1991 Soundcraft Spirit Live that i've refurbished somewhat. (I recently did an ITB vs analog mix comparison - the mixer still gets ME better results in quicker time and much more clarity).

But I'll be damned, if what you are saying is the case. But the Behringer as a pre/post converter knob that I can easily sweep. I have to pay close attention to hear a difference, and the sound indeed does "flatten" i.e. I lose that hi-fi quality.

[wearashirt]

I use the line inputs on my Audient ASP008 more than the mic inputs with no issues when it comes to sound degradation. This uses the same preamp design as your iD14.

So the line inputs on the asp008 are ONLY the mic inputs on the audient id14mk2?

[ef37a]

Any interface that has extra, 3/4 line inputs will serve. One of the best interfaces for its money, around £150 is the Native Instruments KA6 Mkll. You might find a Mk1 cheaper and that will be equally good.

If dirt cheap is your thing the Behringer UMC204HD has 'inserts' which are post the mic pres.

Dave.

[wearashirt]

Any interface that has extra, 3/4 line inputs will serve. One of the best interfaces for its money, around £150 is the Native Instruments KA6 Mkll. You might find a Mk1 cheaper and that will be equally good.

If dirt cheap is your thing the Behringer UMC204HD has 'inserts' which are post the mic pres.

Dave.

Yeah I know, but thanks for bringing that up. I'm curious why - of all companies - Behringer would still include TRS inserts in their interfaces.

Well, i really like the Behringer 1820's preamps for recording, which is why I was looking for a different brand's interface for new preamps, but was disappointed that the top brands all pad line inputs thru the preamps.

Are all combo-jack inputs on interfaces padding line inputs thru the preamps?

My much older focusrite 6i6 1st gen (max 96khz) has separated line-ins, but I infer this only from the fact that it has separate 1/4 inch inputs at the back. I've yet to try the 6i6 for print backs. Maybe I should, though I was also looking forward to printing a mix at 96khz using interfaces rated for 192khz.

[wearashirt]

Now that I'm checking this out, my 1st gen Focusrite 6i6 can accept +28 dBu line input, whereas all the other 2019-2022 competitors that i'm looking to get only accept up to 17.5-22 dBu line inputs.

Wonder if this means anything?

And the Behringer 1820 that I've been printing back through, accepts max of 11 dBu , which in my analogue mixer is roughly equivalent to: channel faders halfway or 75% total length & master faders maxed/unity & DAW outputs at -12 - -6 dbFS.

I've only avoided printing back through the Scarlett at the idea that it was too old and was a mid-tier product for its time (2011-2012) anyway.

[wearashirt]

Now that I'm checking this out, my 1st gen Focusrite 6i6 can accept +28 dBu line input, whereas all the other 2019-2022 competitors that i'm looking to get only accept up to 17.5-22 dBu line inputs.

On the other hand, the focusrite's -80db THD+N is equivalent to 0.01%, whereas those of others have THD+N percentages of 0.005-0.007%.

Numerical conversion sourced from: https://audiointerfacing.com/thdn-percentage-vs-db/

[ef37a]

Now that I'm checking this out, my 1st gen Focusrite 6i6 can accept +28 dBu line input, whereas all the other 2019-2022 competitors that i'm looking to get only accept up to 17.5-22 dBu line inputs.

On the other hand, the focusrite's -80db THD+N is equivalent to 0.01%, whereas those of others have THD+N percentages of 0.005-0.007%.

Numerical conversion sourced from: https://audiointerfacing.com/thdn-percentage-vs-db/

So, get the modern, cleaner gear and make up some 10dB balanced attenuators?

Dave.

[Leopold63]

Not sure if this is any help, but I've started to print my ITB mixes out from my 1st gen Scarlett 18i20, through my ART Trans-X transformer-based pre amp and back into my 18i20.
It adds a certain mojo that I can't quite get with plugins, and the quality certainly doesn't degrade, it gets noticeably better.
The variable impedance controls on the Trans-X help dial in the sound I want.
Maybe something along those lines could be what you are looking for?

Happy New Year!
Leopold

[Wonks]

But I'll be damned, if what you are saying is the case. But the Behringer as a pre/post converter knob that I can easily sweep. I have to pay close attention to hear a difference, and the sound indeed does "flatten" i.e. I lose that hi-fi quality.

That knob is a balance knob between the post-preamp direct sound and sound coming back from the computer. To hear the computer sound, you’ll need to enable monitoring on the tracks of those inputs being recorded (or set to record) and the sound will have been through the Behringer interface A/D, the DAW software and the interface D/A.

Note that with software monitoring enabled for the inputs, at anything other than full left or full right on that control, the signal processing latency will introduce comb filtering and affect the sound.

So full left will let you hear the post-preamp sound whilst full right the sound after being through the interfaces A/D and D/A stages (plus any channel or master bus inserts, EQ effects or sends effects you may have active).

You may well have no channel or master bus effects etc. set, in which case you are really saying that you feel the Behringer interface is slightly less than fully transparent in its operation. Which is one reason that more expensive interfaces exist.

I have no idea what other interfaces may give a noticeable improvement over the Behringer, but the difference you hear is not due to the signal passing through the mic pres but the D/A and A/D converters (and associated circuitry).

[Wonks]

Now that I'm checking this out, my 1st gen Focusrite 6i6 can accept +28 dBu line input, whereas all the other 2019-2022 competitors that i'm looking to get only accept up to 17.5-22 dBu line inputs.

Wonder if this means anything?

All it really means is that on the 6i6, the input signals have to be a lot hotter to get the same signal level in the DAW as on the competitors. That signal level is directly related to 0dBFS from the A/D converter.

Levels of +28dBu are rarely encountered these days, it's more of a throwback to analogue tape days when line level signals were generally hotter and the equipment ran with decent headroom . Now +4dBu and the lower domestic electronics -10dBV are the most common line level standards, inputs with such high maximum input levels mean that even 'hot' signals from +4dBu outputs don't make the most of the available signal range (which is normally fine as decent digital headroom is good) but lower line level signals can end up lower than you'd like.

But you'll find that a lot of those maximum signal levels are in conjunction with use of the pad for the input. On the 6i6 you have a 10dB pad, so the line input maximum level is +18dBu without the pad. This is generally going to be more appropriate setting for most of the time.

I've seen various pad values on different interfaces ranging from 8dB to 25dB, and the maximum input signal values are invariably given with the pad engaged. A larger maximum input value doesn't necessarily mean 'better'; it all relates to the signal levels your equipment can provide.

And the Behringer 1820 that I've been printing back through, accepts max of 11 dBu , which in my analogue mixer is roughly equivalent to: channel faders halfway or 75% total length & master faders maxed/unity & DAW outputs at -12 - -6 dbFS.

The Behringer too has pads, and that maximum input level is almost certain to be given with the pad engaged. But as there is only a very poor 'quick start' guide for the unit, and no value for the pad is stated, you have no indication as to what the unpadded maximum input level is.

Given that the maximum input level for the mic and line inputs are quoted as +11dBu, I'd assume that either the 'pad' is in reality a mic/line level switch (as normal mic levels are typically 30dB-40dB lower than line level) or else it's a big typo in the documentation. But I expect the values are correct.

The quoted dynamic range is 106dB(A), which is a good 10dB below Hugh's average figure for a good budget interface (as mentioned on his converter measurement forum post https://www.soundonsound.com/forum/view ... hp?t=79727, so you have all the signs of the UMC1820 providing a lot of inputs for the money, but being very much a budget design with lots of associated compromises (good documentation being one of them).

[wearashirt]

Yeah I thought something was off in the documentation, or something is not being made clear. The pads on the 1820 only say "Line" and "Inst", with another pad called "Pad", which I think combine for 10-15db of more headroom.

I learned a lot in this thread!

[wearashirt]

Not sure if this is any help, but I've started to print my ITB mixes out from my 1st gen Scarlett 18i20, through my ART Trans-X transformer-based pre amp and back into my 18i20.
It adds a certain mojo that I can't quite get with plugins, and the quality certainly doesn't degrade, it gets noticeably better.
The variable impedance controls on the Trans-X help dial in the sound I want.
Maybe something along those lines could be what you are looking for?

Happy New Year!
Leopold

Cool! Are you going into the back (mic inputs) or front (instrument inputs)?

I guess you can call it some sort of soft mastering, like how many mastering set ups pass mixes through an SSL fusion.

[wearashirt]

Levels of +28dBu are rarely encountered these days, it's more of a throwback to analogue tape days when line level signals were generally hotter and the equipment ran with decent headroom . Now +4dBu and the lower domestic electronics -10dBV are the most common line level standards, inputs with such high maximum input levels mean that even 'hot' signals from +4dBu outputs don't make the most of the available signal range (which is normally fine as decent digital headroom is good) but lower line level signals can end up lower than you'd like.

But you'll find that a lot of those maximum signal levels are in conjunction with use of the pad for the input. On the 6i6 you have a 10dB pad, so the line input maximum level is +18dBu without the pad. This is generally going to be more appropriate setting for most of the time.

I've seen various pad values on different interfaces ranging from 8dB to 25dB, and the maximum input signal values are invariably given with the pad engaged. A larger maximum input value doesn't necessarily mean 'better'; it all relates to the signal levels your equipment can provide.

Can you explain the difference between maximum input level and dynamic range?

[Hugh Robjohns]

Maximum Input Level is the highest analogue input signal that can be accepted without exceeding 0dBFS.

The Dynamic Range (in the context above) is the difference between 0dBFS and the converter's noise floor.

[Leopold63]

Cool! Are you going into the back (mic inputs) or front (instrument inputs)?

I guess you can call it some sort of soft mastering, like how many mastering set ups pass mixes through an SSL fusion.

I've got two pairs of balanced XLR to TRS cables so I'm going from a pair of line outs on the 18i20 into the Trans-X, then back into another pair of line inputs on the back of the 18i20 on channels 7 and 8.
I leave them plugged in permanently like that. If I need extra inputs I have a Behringer 8200 in the rack as well, which comes in handy for tracking live bands without having to unplug my Trans-X (which I also love to track through).

I am indeed using this method for mastering duties and not mixdowns.
Once I've got the stereo mix as finished as I can get it, I render down then open another instance of Reaper with that mixdown on one track, and another track set to record armed.

The stereo mixdown track is sent to the inputs of the Trans-X. The returns from the Trans-X are muted in Scarlett MixControl to so I can monitor in Reaper what it sounds like coming out of the Trans-X, which is sent to the stereo inputs on the new track.
I then record back into Reaper in real time, just like old-school tape, and I can adjust the controls on the pre to taste and hear what it is doing whilst also running my mastering tools - limiter, overall EQ etc. - and hearing what they are doing in real time. I also run some plugins on the mixdown track before it goes to the Trans-X if it needs some colour as the ART is a clean pre unless you really push it, something like a Daking, it just makes it sound "better" for want of a way to describe it!

Sorry if that sounded a bit long-winded, but after 20 odd years of working totally ITB this is giving my mixes a similar feel to when I was working with tape back in the day and it makes me excited to get my masters sounding better than they have ever done, with a lot less work.