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Black Lion Revolution 2x2 Review (Audio Interface)

AdamG247

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Lots of things weigh in perception. Color, heft, general appearance, time of day, memories, etc. Noise also colors everything we hear in daily life. That said, I am surprised the BLAR did so poorly with standard metrics. Quite a bit of hype on this unit. I’d love it if someone like Jacob went the blind listening route on YouTube.
Welcome Aboard @jonljacobi.
 

JDP

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What kind of tests you can carry out will depend on the tools at your disposal. User interface, build quality, driver stability and quirks, that sort of stuff should take little more than your own senses. Roundtrip latency can be measured easily by routing just one channel of a stereo pair through the interface under test and determining the delay in your DAW of choice, you just need a good test signal with an abrupt start (maybe a snare hit or similar) or other distinctive characteristic that is easily identified visually in waveform view.

If max output level and line input level are close, doing loopback testing using RMAA and/or REW will tell you something about the qualities of A/D + D/A combined. By turning down the output, you may be able to test even the mic input from minimum to maximum gain (noise will generally be excessive unless you have an analog attenuator, but it should give you a pretty good idea about preamp and ADC nonlinear distortion and frequency response).

Getting an idea of mic input noise generally is quite helpful. Subjectively, a lowish-impedance dynamic mic (the Shure SM7B being a very common and notorious example) should give you a decent idea, particularly if you have a few different candidates to compare with... that should weed out any real turkeys quickly.
Ideally though, you want to determine the input noise level for a typically 20 kHz bandwidth with a known source impedance plugged into the input (either a short or 150 ohms, typically).
That takes an absolute level calibration. For this, you would first take an output of low impedance and measure its output voltage at a known, near 0 dBFS level (as determined e.g. with a multimeter that requires at least a low-voltage AC range, preferably one TrueRMS capable - take note of the valid frequency range, the simple ones are generally optimized for mains frequencies). Then you would reduce digital generator level by a known amount, enough to not overdrive the mic input (maybe arouind -10 dBFS in). This then allows you to reference input dBFS levels to analog voltage levels, for both signal and noise. Once you have that, you unplug your reference source and swap to your short or 150 ohm resistive noise source.
Determining input dBFS levels can be done using rather rudimentary software tools, even Audacity will do if its meter dB range is set large enough. At 44.1 kHz, applying Audacity's A-weighting EQ curve should give decently accurate A-wtd results as-is, at higher rates a steep 20 kHz lowpass would be required in addition as A-weighting is not defined beyond that.

I suggest you take a look at @Julian Krause's channel, he's got a pretty decent set of tests he runs these days (he's also got a video where he explains how to determine input noise).

If you want to fully characterize a modern high-performance interface, ideally you want a full-blown audio analyzer like an Audio Precision, a dScope or a R&S UPV or UPL, but those costs thousands or tens of thousands of dollars even used. The tighter your budget, the more limited you'll be and the more resourceful you'll have to get. The converter performance alone isn't actually that expensive - an RME ADI-2 Pro FS should generally be as good as any of them, for example (while still offering substantial flexibility in terms of levels), a QuantAsylum analyzer isn't a slouch either (their new QA402 should have been out by now but seems to have been delayed), and if you just need a superb DAC you don't need to spend more than a few hundred either - but it's the signal conditioning and automation that'll cost you dearly. For just a few spot checks, you can often cobble something together quite inexpensively.
Just saw your response, I would've replied sooner but for some reason I stopped getting email alerts to notify me. Either way, that's a lot of information and I don't just want to get a bunch of numbers and charts and present them, I want to fully understand what I'm talking about, so I think a one step at a time approach is best. For now, I'd like to fully learn and understand how to measure input noise. I'm ordering a SM7B (was going to anyway) but where would one get a "known source impedance", I've seen podcastage use a 150 ohm resistor but search results don't pull up anything.
 

AnalogSteph

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[...] I want to fully understand what I'm talking about, so I think a one step at a time approach is best.
What is your professional background? With these things, having gone through some lectures on digital processing and analog or RF engineering won't go amiss. RF is quite helpful because it'll familiarize you with concepts like noise figure, Friis' formula etc. - I had to re-derive the equivalent of Mr Friis for audio circuits (low source impedance, high load impedance), but the basic reasoning is quite analogous. (The intro to chapter 8 of The Art of Electronics, 3rd ed., should also do as an introduction to noise in electronic circuits.)

Just messing about with RMAA for years combining different hardware also gives you a feel for the graphs, what's good and where something has probably gone wrong. (It'll also teach you that the difference between 20 kHz flat and A-weighted on white noise is about 2.3 dB.) Believe it or not, when RMAA actually was a common sight in computer audio reviews about a decade ago, there were a lot of garbage results floating around - sometimes there was plain clipping, at other times sample rates clearly did not match, few had the capabilities to do more than just loopback testing, and almost no-one knew how to spot and even less how to avoid ground loops in the measurement setup.
I'm ordering a SM7B (was going to anyway) but where would one get a "known source impedance", I've seen podcastage use a 150 ohm resistor but search results don't pull up anything.
A 150 ohm resistor will in fact fit the bill - it remains just about perfectly resistive far above the audio band. (A bog-standard 1/4 W metal film job will do. Make sure to keep loop area small, e.g. stick it directly into the XLR input jack or twist any length of cable.)

This particular value is an industry standard, you may however also consider using ~50 ohms (e.g. a 51 ohm; mics in this range are mostly historical at this point but I still found a single one sold brand new last time I checked) or even a dead short as an alternative for better resolution at low input noise. Otherwise your error margins would get quite big when trying to calculate the input noise density just for the input itself (I have a calculator for that) on a very low-noise specimen. Shouldn't be an issue on the Revolution 2x2, but something like an M-Audio AIR 192 | 4, Tascam US-2x2HR, SSL 2(+) or Audient iD(1)4 MkII would be a different matter.

The good part about an actual mic is that it gives you actual signal to compare to as well, without it having to be a two-step process. You just have to find some sort of sound source of preferably low but repeatable level, which may be a little easier said than done at times.
 
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D

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Just a message for JDP

I just wanted to say man it's so refreshing to see someone make such a mature response to criticisms of your video review. I have a lot of respect for people who admit they may not have the knowledge they desire, and to be so open to learning it. It's not an easy task to take on researching the science of audio, it can be approached from many different angles and man there are a lot of people online who are ready to jump at the chance to share their info lol.

I hope you have as much fun as I do with this stuff and welcome to the forums.
 

JDP

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What is your professional background? With these things, having gone through some lectures on digital processing and analog or RF engineering won't go amiss. RF is quite helpful because it'll familiarize you with concepts like noise figure, Friis' formula etc. - I had to re-derive the equivalent of Mr Friis for audio circuits (low source impedance, high load impedance), but the basic reasoning is quite analogous. (The intro to chapter 8 of The Art of Electronics, 3rd ed., should also do as an introduction to noise in electronic circuits.)

Just messing about with RMAA for years combining different hardware also gives you a feel for the graphs, what's good and where something has probably gone wrong. (It'll also teach you that the difference between 20 kHz flat and A-weighted on white noise is about 2.3 dB.) Believe it or not, when RMAA actually was a common sight in computer audio reviews about a decade ago, there were a lot of garbage results floating around - sometimes there was plain clipping, at other times sample rates clearly did not match, few had the capabilities to do more than just loopback testing, and almost no-one knew how to spot and even less how to avoid ground loops in the measurement setup.

A 150 ohm resistor will in fact fit the bill - it remains just about perfectly resistive far above the audio band. (A bog-standard 1/4 W metal film job will do. Make sure to keep loop area small, e.g. stick it directly into the XLR input jack or twist any length of cable.)

This particular value is an industry standard, you may however also consider using ~50 ohms (e.g. a 51 ohm; mics in this range are mostly historical at this point but I still found a single one sold brand new last time I checked) or even a dead short as an alternative for better resolution at low input noise. Otherwise your error margins would get quite big when trying to calculate the input noise density just for the input itself (I have a calculator for that) on a very low-noise specimen. Shouldn't be an issue on the Revolution 2x2, but something like an M-Audio AIR 192 | 4, Tascam US-2x2HR, SSL 2(+) or Audient iD(1)4 MkII would be a different matter.

The good part about an actual mic is that it gives you actual signal to compare to as well, without it having to be a two-step process. You just have to find some sort of sound source of preferably low but repeatable level, which may be a little easier said than done at times.

I'm a studio guy, I have no electrical background whatsoever, I've worked in home and pro studios for about 20 years now and have been a gear junkie the entire time, constantly buying and selling gear along the way and helping local guys build their home studios. Regarding mic input noise I read this from a Sound Devices page on how to measure it:


  • Calibrate the gain between units under test using a tone generator (or other source with a known output level) plugged into a mic input. Adjust the gain for the same level out of the headphones. Doing this makes sure you have the same amount of total gain through both preamps.
  • Plug in a 150 ohm resistor across pin-2 and pin-3 of the XLR connector. This emulates a microphone, but without the acoustic output of a microphone. Alternatively, a dynamic microphone with an on/off switch will accomplish the same.
  • Now listen to the difference between the units.
So I'm assuming I can skip the whole resistor thing and just use the SM7B I have coming, yes? I'd really like the simpler method (mic seems simpler to me :)) if it's still effective as my content is aimed at your average guy (like myself!) who prefers things explained in an easy to understand way. If that works, what would you recommend using as a "tone generator (or other source with a known output level)"?

Thanks joshmelo! I'm just doing what I can with what I've got and honestly I'm always looking for more topics I can touch on during the course of a video. This (along with my photography) is my livelihood so if the product can be improved, I definitely want to do it!
 

acctx

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Lots of things weigh in perception. Color, heft, general appearance, time of day, memories, etc. Noise also colors everything we hear in daily life. That said, I am surprised the BLAR did so poorly with standard metrics. Quite a bit of hype on this unit. I’d love it if someone like Jacob went the blind listening route on YouTube.

I haven't watched the blind listening video so this may have been mentioned, but I suspect what's also going on with most of the new interfaces listening experiences is that when you set your new interface up you basically give yourself at least a 10-15min ear break while you're connecting things, installing drivers etc. So no matter what, after an ear break everything will sound crisper, smoother, warmer whatever... because rested ears... so instantly "better" and "sounds good".
 

dfuller

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Thinking back on this again, how much of this performance is limited by the codec itself? Spec sheet (so, roughly speaking best case) THD+N of the CS4272 is -100dB.

This is made all the more disappointing by the fact that Audient managed to squeeze in a higher grade discrete ADC and DAC (as opposed to a monolithic codec) into a cheaper box (the iD14 Mk II).
 
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I haven't watched the blind listening video so this may have been mentioned, but I suspect what's also going on with most of the new interfaces listening experiences is that when you set your new interface up you basically give yourself at least a 10-15min ear break while you're connecting things, installing drivers etc. So no matter what, after an ear break everything will sound crisper, smoother, warmer whatever... because rested ears... so instantly "better" and "sounds good".

One would hope that you're not actually installing drivers between tests. You can just plug both interfaces in and switch between via OS sound control panel or in my case, windows drop down menu.

You'll still have to switch cables but if you do it right that should only take like 10 seconds.
 

jonljacobi

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I just saw Julian Krause's YouTube review. Great job as usual. But I'm struck by the same thing. How did they get so much noise and latency from what seems to be top-flight componentry? It really makes me wonder. Especially as they have a lot to lose reputation-wise. Maybe a few of the designer types might shed some light.

All that said, it sounds fine subjectively, but that's as far as I'll go, as my ears really can't tell the difference once the quality goes exceeds a certain standard. And nearly all the interfaces here exceed said standard. Which I suppose is the point. You can get just as good or better for half the price.
 

AnalogSteph

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Regarding mic input noise I read this from a Sound Devices page on how to measure it:
  • Calibrate the gain between units under test using a tone generator (or other source with a known output level) plugged into a mic input. Adjust the gain for the same level out of the headphones. Doing this makes sure you have the same amount of total gain through both preamps.
  • Plug in a 150 ohm resistor across pin-2 and pin-3 of the XLR connector. This emulates a microphone, but without the acoustic output of a microphone. Alternatively, a dynamic microphone with an on/off switch will accomplish the same.
  • Now listen to the difference between the units.
That's from here, right? This guide is intended to provide a comparison of relative EIN levels of two different mic inputs under industry standard conditions (150 ohm source for both). IOW, if one input is at -128 dBu and the other at -125 dBu, you'll see a 3 dB difference in noise. This can be useful if you have already gone to great lengths to determine the absolute EIN level of one particular unit before, so that may then serve as a reference for other measurements.
So I'm assuming I can skip the whole resistor thing and just use the SM7B I have coming, yes? I'd really like the simpler method (mic seems simpler to me :)) if it's still effective as my content is aimed at your average guy (like myself!) who prefers things explained in an easy to understand way.
An outlier like this unit will be plainly obvious when just recording normally with the SM7B, as @Julian Krause's video will attest. (The expression "hissy like a mad snake" comes to mind.)

If you want to quantify the difference between units, you'd need some sort of sound source of precisely reproducible level at a fixed position in the studio (maybe a spare computer or MP3 player with some speakers whose volume is not easily adjusted), and the mic would have to be kept in the same place as well.
If that works, what would you recommend using as a "tone generator (or other source with a known output level)"?
An audio interface line-out with e.g. REW as a software tone generator (you could also use Audacity's) should do fine. You just have to measure the voltage generated at a given digital level (e.g. -6 to -12 dBFS) either with the multimeter or using an input of precisely known (calibrated) 0 dBFS level, then reduce software tone generator level until it is well away from clipping levels when run into the input under test at full gain (which is what you need for EIN testing). Try around -60 dBFS or so for starters. The difference will be equally reflected in voltage, so you still know what the absolute level is. (Converting your measured voltage to dBu first would make this part much easier.) This can then serve as a reference for any noise level measured after unplugging the reference output and replacing the 150 ohm resistor.

This sounds a lot more convoluted than it is, really. Perhaps it is easier to understand if you go about it backwards:
You want to generate a reference signal (e.g. sine) low enough to not overdrive the input under test at full gain.
For this, you are using a digital tone generator and audio interface output at given settings. Note them down, along with level achieved on the input.
Exploiting the inherent linearity of the system, you can increase digital generator level until a typical multimeter with a 2V AC range (one with only 200/600V~ ranges is useless) provides a decent amount of resolution, and measure the output voltage. Note down generator level and determine the difference between both settings. (This approach is generally the most practical, as very few of us have an audio millivoltmeter at their disposal while decent enough multimeters are reasonably common.)

For example, you might find:
-12 dBFS generator level at full tilt on the interface translates to 0.78 Vrms or ~0 dBu. (That's a +12 dBu output.)
Then -60 dBFS will give -48 dBu.
Your digital input level will then tell you where input 0 dBFS is. You might find -8 dBFS in, so obviously input 0 dBFS level has to be 8 dB higher than -48 dBu, or -40 dBu. (Note: Last time I checked, Audacity would display the level of a full-scale sine as -3 dB and takes a square wave to get to 0 dB, so keep that in mind. If you get a -80 dB noise floor displayed on the meters, it's -77 dBFS. Be sure to extend meter / dB range in settings as far as needed.)

Audacity has an EQ preset for A-weighting. Applying a high-order 20 kHz lowpass filter may be advisable first (LPF may be an optional Nyquist component that has to be downloaded first).
 

dfuller

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I just saw Julian Krause's YouTube review. Great job as usual. But I'm struck by the same thing. How did they get so much noise and latency from what seems to be top-flight componentry? It really makes me wonder. Especially as they have a lot to lose reputation-wise. Maybe a few of the designer types might shed some light.
I'd assume it's a combination of poor design and being limited by the CS4272. The preamps shouldn't be that noisy especially considering we've had preamps at an EIN of -130ish dBu for literally 50 years (the Neve 1073 has an EIN of -125dB at 60dB gain and that design is from the mid 1970s). It's easier with low noise IC op amps than discrete transistors and transformers so it's a pretty bad design screwup.

As for the CS4272, it's just an older low cost part with a high noise floor, even if much of that is ultrasonic.
 

Chez

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So much for high end IC's per the marketing blah blah.
Maybe some will come up with a DIY mod? or preferably BLA would make an update available to current owners.
 

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One thing I've noticed is that these convos, discussions and critiques are normally 80 percent of musicians who will be tracking instruments, and Podcasters who use dynamic mics. Hip hop has always been looked at as a joke in the audio world regarding vocals and only kind of garnered a little respect once full instrumental tracks were being made with virtual instruments.

If you're at home. Rapping. Especially if you're just starting this interface is great. I own this interface and a neumann tlm102 and I've never had to crank the gain past 2 o clock. Really only do that to record skits during moments that are supposed to sound like people are outside or far away. 1230 all the time to track rap vocals. I don't have anything to compare it to except something I think was called an m audio mobile pre that I had preusb mic era as a kid with a "studio."

The 400 dollars is probably definitely the software. It comes with a hundred dollar daw and about a hundred dollars in plugins. If you spend time with the gain cranked to 5 and 6 o clock or max then this probably isn't the interface for you. At the same time if you spend most of your time with the gain cranked to max I can't see how a cheaper interface would give you less noise and a better sound.

My decision was based off their word and rep and compatability with outboard equipment later. I'm satisfied with it but I would only recommend it to someone who has a condenser mic and they're here for vocals as opposed to instruments. My choice was between the motu and the black lion and the motu looked great and seemed great but instincts told me that it wouldn't last 3 years from now. Not saying the rev 2x2 will still work for me 3 years from now but nothing shows that it won't.

Also...I don't think u should look at an audiophiles spec research to help you make a decision if you're not an audiophile yourself. No one is gonna put on headphones, crank gain and hear the noise difference so if you don't have these same tools at home to help you see accurate specs and measurements why would you even care?? If you wanna buy one interface to record your quiet mics and instruments then you're gonna have to spend some money. But if you just tryna rap or podcast(with a condensor) this or something cheaper should be fine. Get line boosts or preamps for your quiet mics or continue dealing with noise floors
 

AnalogSteph

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The preamps shouldn't be that noisy especially considering we've had preamps at an EIN of -130ish dBu for literally 50 years (the Neve 1073 has an EIN of -125dB at 60dB gain and that design is from the mid 1970s). It's easier with low noise IC op amps than discrete transistors and transformers so it's a pretty bad design screwup.
I have a hunch that this may have been someone's first balanced mic preamp design. If you search around for schematics of one, you'll come across several designs that wouldn't be cutting it in the noise department. Several kOhms in series with your source are generally spelling bad news in this regard.

The best-performing circuits tend to be hybrids. Fully discrete ones tend to lack the complexity for low distortion, while at the same time it takes rather expensive low-noise opamps to reach the voltage noise levels of garden variety discrete transistors.
 

dfuller

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I have a hunch that this may have been someone's first balanced mic preamp design. If you search around for schematics of one, you'll come across several designs that wouldn't be cutting it in the noise department. Several kOhms in series with your source are generally spelling bad news in this regard.

The best-performing circuits tend to be hybrids. Fully discrete ones tend to lack the complexity for low distortion, while at the same time it takes rather expensive low-noise opamps to reach the voltage noise levels of garden variety discrete transistors.
Yup, agreed with all of this. To be honest, I don't hate the idea of using a coupling transformer at the input of a mic preamp. They're passive, so they contribute negligible noise, and at that voltage level you don't need much of a core to have low-enough distortion. Only downside is cost, but considering I bought a standalone transformer coupled in and out preamp (which uses Jensens and Altrans, which aren't cheap) for $500 I don't think it's impossible to do so in a $400 interface that doesn't need the output transformers...

Plus, marketing on that would be amazing. "OMG LOOK AT OUR VINTAGE TRANSFORMER MIC PRES" is fantastic marketing material.
 

AnalogSteph

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I don't really see much of a benefit aside from novelty value though - it's not like mic inputs need galvanic isolation. In fact, the gain added by the transformers may leave maximum input level handling a little lower than desired. And then there's the fact that for all the extra cost and space taken up you could probably build a first-rate mic preamp. I can't imagine that BOM cost for a typical mic preamp channel exceeds 5 bucks very often... $1 for a half-decent pot, $1.50 for a somewhat modern opamp, $1.50 for discretes and passives, and that's by no means as low as you can go.

EDIT: Looks like BLA has posted a comment to Julian Krause's review:
We have seen this review and stand by everything we have said about the Revolution 2x2 and the experiences of thousands of people around the world match our own. This interface sounds absolutely incredible. The fact of the matter is, this review does not and cannot translate to the real world. We also own Audio Precision machines- 2 of them- Just because you own a hammer doesn’t make you a carpenter. We deal with these machines day in and day out. We have been very honest and open about the fact that our entire design process revolved around making an interface that sounded better than everything else available anywhere near this price range, and that the specs come after. Specs absolutely do not tell the entire story when it comes to how good something sounds. Should we sacrifice how a product sounds so it could look good on a machine or a piece of paper? Thats insane.

It is very easy (like VERY easy) to design a quiet preamp and convertor circuit with low distortion, in fact, most convertor chips have application notes on how to optimally use their chip for these two things but the fact of the matter is these implementations would make one of most boring and uninspiring sounding interfaces you’ve ever heard. We have made a career out of fixing that with our mods of other companies interfaces.

In the end one and only one thing is a real measurement of the quality of an interface, and that is YOUR experience and how well you can make you make music on it. Everything else is just a matter of record when it comes to specs. THERE IS NO SPEC that will show you on paper how much your ears and brain will enjoy using the interface- imaging, separation of instruments, stereo field, 3 dimensionality and phase relationships between the 2 channels. Any reviewer can rattle off specs but not focusing on the sound of the interface is as bad as a car reviewer who reviews a Ferrari and says it is a bad car since the windows are too small and it is too loud. Cars and interfaces are very much the same, cars should be driven and interfaces should be listened to… everything else is just numbers on paper.
Let's just say I ain't convinced. If we're supposed to judge the interface by the quality of its recordings, well, it obviously turns Julian's SM7B into the Mad Snake Special Edition, and I can't find anything good-sounding about that. Guess what, measurements aren't just taken for amusement purposes and do in fact matter. Nothing has changed in this regard from a decade ago.

And they've got not one but two APs? For shame. Pearls before swine. Not like APs are particularly well-equipped for EIN measurements out of the box, but anyway. (Determining EIN with decent enough accuracy can be done with fairly modest means, as outlined earlier in this thread.)
 
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dfuller

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I don't really see much of a benefit aside from novelty value though - it's not like mic inputs need galvanic isolation. In fact, the gain added by the transformers may leave maximum input level handling a little lower than desired. And then there's the fact that for all the extra cost and space taken up you could probably build a first-rate mic preamp. I can't imagine that BOM cost for a typical mic preamp channel exceeds 5 bucks very often... $1 for a half-decent pot, $1.50 for a somewhat modern opamp, $1.50 for discretes and passives, and that's by no means as low as you can go.
It's absolutely for novelty value in this case, but considering BLA is "all flash, little substance" you cannot deny the marketing. But, transformers do have some benefits, the way I see it. The extra gain is useful - and you can get back the rest with a switchable pad. This maybe doesn't work quite as well if you're doing the half-assed "line input is the mic input but padded way the hell down" thing but again, for $400 and 2 in/2 out, I'd expect them to do that.
 
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