# Focusrite Scarlett 2i2 vs Roland UA-55 Quad-Capture



## Phillips

Hi please can someone tell me which is the better choice?

Thanks in advance


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## AudiocRaver

Phillips said:


> Hi please can someone tell me which is the better choice?
> 
> Thanks in advance


I do not know much about the Scarlet. I have a Quad-Capture, though.

One thing I really like about it is the mixer panel in the device driver has a numeric gain indication for each of the two mic preamps, in 0.5 dB increments. So the gain can be set with high repeatability. It is very convenient for gain calibration.

My one complaint is that it does not have a LED indicator for Phantom Power On. Seems like a no-brainer, almost every cheap interface has one. It is not a show-stopper, though. I really like the numeric gain readout.


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## Phillips

Hi Wayne thanks

So it has a digital control?

Thank you


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## AudiocRaver

Phillips said:


> Hi Wayne thanks
> 
> So it has a digital control?
> 
> Thank you


Not really a digital control. The only control is the knob on the front panel of the Quad-Capture, which is an analog control, no detents, pure analog.

But there is a digital READOUT of the gain set by that knob. So it can easily be set to any desired gain, in 0.5 dB increments.

For instance, when I want to calibrate the gain for use with my BeyerDynamic MM-1 mic with REW, I know that the +27.0 dB gain setting is just right for a 75 dB SPL with a -30 dBFS measured input level. I just

turn on some periodic pink noise, the precise level does not matter
turn the input gain for the mic preamp to 27.0 dB
NOW adjust the REW output level so the measured input llevel is -30 dBFS on the REW SPL meter
click on CALIBRATE, enter 75.0 for the SPL reading, click on FINISH.
calibration is DONE!


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## Phillips

AudiocRaver said:


> Not really a digital control. The only control is the knob on the front panel of the Quad-Capture, which is an analog control, no detents, pure analog.
> 
> But there is a digital READOUT of the gain set by that knob. So it can easily be set to any desired gain, in 0.5 dB increments.
> 
> For instance, when I want to calibrate the gain for use with my BeyerDynamic MM-1 mic with REW, I know that the +27.0 dB gain setting is just right for a 75 dB SPL with a -30 dBFS measured input level. I just
> 
> turn on some periodic pink noise, the precise level does not matter
> turn the input gain for the mic preamp to 27.0 dB
> NOW adjust the REW output level so the measured input llevel is -30 dBFS on the REW SPL meter
> click on CALIBRATE, enter 75.0 for the SPL reading, click on FINISH.
> calibration is DONE!


Hi Wayne thank you

How do you know the 75db spl, or is there any other way of doing this?

I am trying to work out if I get the either of these two or get a plug in play mic/pre e.g. the XTZ. Please feel free to comment.

With the digital readout it would come in handy to make sure it stays at that level, instead of having mic gain pots?

Is this the UA - 55 http://www.roland.co.nz/products/quad-capture/ the one you have?
Is there another Roland UA - 55 Quad Capture or is this the only one, I thought I saw the same name but with "Professional" at the end?

Thank you, trying to understand this.


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## AudiocRaver

Phillips said:


> How do you know the 75db spl, or is there any other way of doing this?


When I say "I know that the +27.0 dB gain setting is just right for a 75 dB SPL with a -30 dBFS measured input level," the only way to know this is to go through a regular level calibration using an SPL meter. This was done once a number of years ago, and is reconfirmed from time to time.

The little procedure I outlined is simply a shortcut for day-to-day REW setup, an example of what is possible with the digital gain readout. If you trust that you can simply set the knob and never move it, then the gain readout does not help you. But then what if you bump it or move it without thinking? Then you have to re-calibrate. Can you set the interface aside for a few weeks and trust the seting of that gain next time you pick it up? I am not comfortable doint that. Can you _mark_ the position of the knob? Probably only accurate to +/- 2 or 3 dB. The readout is accurate to +/- 0.5 dB.

It is not really THAT big a deal, just a little convenience / time shortcut thing that I like.



> I am trying to work out if I get the either of these two or get a plug in play mic/pre e.g. the XTZ. Please feel free to comment.


The XTZ mic is good, it is calibrated for 90 degree use. There is no calibration file. It is made to be +/- 1 dB accurate. So there is no way to accurately use it in the 0 degree orientation, unless you create your own calibration file, which is possible but is a pain.

A USB mic or the XTZ mic will not allow you to use timing loopback for accurate time measurements. Having that feature is a must for me. I still use a UMIK-1 from time to time and have and use the XTZ mic, too, where FR is all that is needed, and no time info is necessary.

I have no experience with the Scarlet, and no idea what special features it might have.



> With the digital readout it would come in handy to make sure it stays at that level, instead of having mic gain pots?


The Quad-Capture DOES HAVE MIC GAIN POTS, like almost all audio interfaces. The digital readout tells you what the gain is set at using that pot. Turn the knob, see the readout number change accordingly, set the gain _accurately_ where you want it with the front-panel gain pot by watching the digital gain readout.



> Is this the UA - 55 http://www.roland.co.nz/products/quad-capture/ the one you have?


Yes. Pretty sure I paid about $250 for mine.



> Is there another Roland UA - 55 Quad Capture or is this the only one, I thought I saw the same name but with "Professional" at the end?


It is the only one I have ever seen.


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## jtalden

I use the 2i2 audio interface. It is a very good inexpensive audio interface for REW use. It has a couple very minor shortcomings, but is basically as capable as any of the other low priced units. Its shortcomings are unlikely to be significant for any of the typical REW applications.


I also have an easy method to calibrate the REW SPL meter when using the 2i2. It does not require an SLM. The method could be used for other similar audio interfaces as well. The advantage of the process is that it is quick and easy. It is almost as easy as the method Wayne found for the Quad-Capture Interface. It only requires a TRS to XLR loopback cable. For those that change the input gain on the audio interface between REW sessions this is much easier than using the SLM method or the method using a multi-meter. [It is basically a simplification of the multi-meter method I previously used.] 


I can provide details if you or others will find this helpful.


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## Phillips

Hi Wayne thank you very much

Does the Quad Capture have digital readouts for inputs and outputs? 
I think the digital readout, this would be handy like you say for re assurance that it is exactly at the correct setting like you say bumping etc.

So I need a reference reading/point for SPL

I thought there is a XTZ pro mic calibration file?

Thanks again


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## AudiocRaver

jtalden said:


> I also have an easy method to calibrate the REW SPL meter when using the 2i2. It does not require an SLM. The method could be used for other similar audio interfaces as well. The advantage of the process is that it is quick and easy. It is almost as easy as the method Wayne found for the Quad-Capture Interface. It only requires a TRS to XLR loopback cable. For those that change the input gain on the audio interface between REW sessions this is much easier than using the SLM method or the method using a multi-meter. [It is basically a simplification of the multi-meter method I previously used.]
> 
> I can provide details if you or others will find this helpful.


I, for one, am curious what you have come up with. Please share.



Phillips said:


> Does the Quad Capture have digital readouts for inputs and outputs?


Only for the first two inputs. Not for inputs 3 and 4 (digital) and not for the outputs.



> I think the digital readout, this would be handy like you say for re assurance that it is exactly at the correct setting like you say bumping etc.
> 
> So I need a reference reading/point for SPL


Yes, initially. This can be done with a borrowed SPL meter, or with a UMIK-1 or similar calibrated USB mic that has the reference gain in the mic calibration file. Once it has been determined, and the input gain is set as described above, that reference meter or mic is no longer needed for that purpose. So, if there is a way to borrow such a reference, you will only need it for a short time. Some would want to keep a SPL measurement reference around for quick level checks or whatever, and some would be fine without it. That is your call.



> I thought there is a XTZ pro mic calibration file?


Oops. Yes, you are correct, there is one. I had forgotten that.

The only driver needed is the Windows generic driver. And there is a _single_ calibration file which works for _all_ XTZ Pro mics, not a unique calibration file for each mic manufactured, like most other calibrated mics. The XTZ Pro mics are designed and manufactured (or selected) to work with that calibration file. The calibration file covers the range from 10 Hz to 22 kHz.


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## Phillips

jtalden said:


> I use the 2i2 audio interface. It is a very good inexpensive audio interface for REW use. It has a couple very minor shortcomings, but is basically as capable as any of the other low priced units. Its shortcomings are unlikely to be significant for any of the typical REW applications.
> 
> 
> I also have an easy method to calibrate the REW SPL meter when using the 2i2. It does not require an SLM. The method could be used for other similar audio interfaces as well. The advantage of the process is that it is quick and easy. It is almost as easy as the method Wayne found for the Quad-Capture Interface. It only requires a TRS to XLR loopback cable. For those that change the input gain on the audio interface between REW sessions this is much easier than using the SLM method or the method using a multi-meter. [It is basically a simplification of the multi-meter method I previously used.]
> 
> 
> I can provide details if you or others will find this helpful.


Hi thanks for your reply

I would also like to know how you did it + would this work for other programs?

Thanks again


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## Phillips

AudiocRaver said:


> I, for one, am curious what you have come up with. Please share.


+1



AudiocRaver said:


> Only for the first two inputs. Not for inputs 3 and 4 (digital) and not for the outputs.


Ok, mainly looking at the volume output if that gets bumped?



AudiocRaver said:


> Yes, initially. This can be done with a borrowed SPL meter, or with a UMIK-1 or similar calibrated USB mic that has the reference gain in the mic calibration file. Once it has been determined, and the input gain is set as described above, that reference meter or mic is no longer needed for that purpose. So, if there is a way to borrow such a reference, you will only need it for a short time. Some would want to keep a SPL measurement reference around for quick level checks or whatever, and some would be fine without it. That is your call.


How would I go about this?



AudiocRaver said:


> Oops. Yes, you are correct, there is one. I had forgotten that.
> 
> The only driver needed is the Windows generic driver. And there is a _single_ calibration file which works for _all_ XTZ Pro mics, not a unique calibration file for each mic manufactured, like most other calibrated mics. The XTZ Pro mics are designed and manufactured (or selected) to work with that calibration file. The calibration file covers the range from 10 Hz to 22 kHz.


So if the calibration covers that range does mean it is calibrated to 10hz to 22khz. I think they say 20hz-20khz?

Thanks again


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## jtalden

See Calibration Procedure Here.


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## AudiocRaver

Phillips said:


> So if the calibration covers that range does mean it is calibrated to 10hz to 22khz. I think they say 20hz-20khz?


Their set site says that measurements cover 16 Hz to 20 kHz.

It also says +/- 1 dB accuracy for the microphone.


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## Phillips

AudiocRaver said:


> Their set site says that measurements cover 16 Hz to 20 kHz.
> 
> It also says +/- 1 dB accuracy for the microphone.


Hi Wayne thank you

I think the program is calibrated to 16 Hz to 20 kHz (graphs)

The mic calibration covers 10hz to 23 kHz with 0 a long way down. Does tis mean it is (the pro mic) calibrated for this, strange they only say from 20 hz - 20 kHz?

Thanks for your time


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## Phillips

jtalden said:


> See Calibration Procedure Here.


Thank you, will look at it 

Thanks again


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## AudiocRaver

Phillips said:


> Hi Wayne thank you
> 
> I think the program is calibrated to 16 Hz to 20 kHz (graphs)
> 
> The mic calibration covers 10hz to 23 kHz with 0 a long way down. Does tis mean it is (the pro mic) calibrated for this, strange they only say from 20 hz - 20 kHz?
> 
> Thanks for your time


I do not have the program, not sure what its capabilities are.

Here is the calibration file:


*Spoiler* 




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20102.38 6.38330
20257.89 6.21606
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21053.68 5.39588
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21712.76 4.74558
21880.73 4.58612
22050.00 4.41652




Sorry, I did not look close at it before, just glanced at the freq limits. The HF numbers look for real, the LF numbers I wonder about. Zero error at 10 Hz for all the mics they make? Doubtful.

I made backup copies and dated the file when I got it from them, so I am sure I did not modify the file, something I have done experimentally before, but NEVER without great care to then either delete it or document what the changes were, so I am confident it is the way it came from XTZ.

Don't know what to say... They advertise 1 dB accuracy down to 16 Hz, that is probably what I would assume is correct.


----------



## Phillips

Hi Wayne thanks I wondered about the lower frequencies.

Please can you clarify for XLR mics, I have a Steinberg CI-1 pre-soundcard
•	For loopback Input 2 to output 2 TRS > TRS or XLR > TRS
•	For SPL calibration Input 2 to output 2 TRS > TRS 
•	For mic cable should be XLR > XLR

For the loopback should the input level (2 or B can't remember) be the same as the mic input or does it not matter?

With SPL using DVM do I measure the input 2 or the mic (input 1)?

Maybe quicker if you could post a photo of the setup (if you can of course)?

Thanks again


----------



## AudiocRaver

Phillips said:


> Hi Wayne thanks I wondered about the lower frequencies.
> 
> Please can you clarify for XLR mics, I have a Steinberg CI-1 pre-soundcard
> •	For loopback Input 2 to output 2 TRS > TRS or XLR > TRS
> •	For SPL calibration Input 2 to output 2 TRS > TRS
> •	For mic cable should be XLR > XLR


timing loopoback: TRS - TRS
SPL calibration: TRS - TRS
mic: XLR - XLR



> For the loopback should the input level (2 or B can't remember) be the same as the mic input or does it not matter?


It does not matter.



> With SPL using DVM do I measure the input 2 or the mic (input 1)?


not sure, I'll get back to you


----------



## Phillips

AudiocRaver said:


> timing loopoback: TRS - TRS
> SPL calibration: TRS - TRS
> mic: XLR - XLR
> 
> 
> 
> It does not matter.
> 
> 
> 
> not sure, I'll get back to you



Thanks Wayne that will be very much appreciated.

I am confused with the cabling and measuring with the DVM

Cheers


----------



## Phillips

Hi Wayne attached is the Steinberg pics

Thanks


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## Phillips

AudiocRaver said:


> timing loopoback: TRS - TRS
> SPL calibration: TRS - TRS
> mic: XLR - XLR
> 
> 
> 
> It does not matter.
> 
> 
> 
> not sure, I'll get back to you


Hi Wayne any news on this

Thanks again


----------



## AudiocRaver

> With SPL using DVM do I measure the input 2 or the mic (input 1)?


The mic input is used for SPL measurements. The gain for input 2 is set arbitrarily, so while that input serves a critical purpose for timing measurement, it does not for amplitude measurement.



> Maybe quicker if you could post a photo of the setup (if you can of course)?
> 
> Thanks again


I wish it was quicker. Posting photos is never "quicker" with forum software.


----------



## Phillips

Thanks Wayne

Have you tried jtalden method?

Thanks again


----------



## Lumen

jtalden said:


> See Calibration Procedure Here.


Your contributions are much appreciated! Thank you for sharing. :T


----------



## AudiocRaver

Phillips said:


> Thanks Wayne
> 
> Have you tried jtalden method?
> 
> Thanks again


I have not. I will say, however, that when John makes a suggestion, you can pretty much take it to the bank for being meaningful, useful and accurate.


----------



## Phillips

AudiocRaver said:


> I have not. I will say, however, that when John makes a suggestion, you can pretty much take it to the bank for being meaningful, useful and accurate.


Thanks you

TBH I haven't gone any further with this, yet


----------



## Lumen

Phillips said:


> Hi Wayne thanks I wondered about the lower frequencies.
> Please can you clarify for XLR mics, I have a Steinberg CI-1 pre-soundcard
> •	For loopback Input 2 to output 2 TRS > TRS or XLR > TRS
> •	For SPL calibration Input 2 to output 2 TRS > TRS
> •	For mic cable should be XLR > XLR





AudiocRaver said:


> timing loopoback: TRS - TRS
> SPL calibration: TRS - TRS
> mic: XLR - XLR





Phillips said:


> For the loopback should the input level (2 or B can't remember) be the same as the mic input or does it not matter?





AudiocRaver said:


> It does not matter.





Phillips said:


> With SPL using DVM do I measure the input 2 or the mic (input 1)?





AudiocRaver said:


> The mic input is used for SPL measurements. The gain for input 2 is set arbitrarily, so while that input serves a critical purpose for timing measurement, it does not for amplitude measurement.


Just wanted to stress that the TRS-TRS connection for loopback _timing_ is crucial for the Focusrite 2i2, which routes phantom power to both XLR inputs simultaneously. AFAIK, The 2i2 will suffer damage if an XLR-TRS connection is used for that purpose, because phantom power will be applied to the output. I learned this the hard way, but it's no longer an issue now that I'm aware.


----------



## jtalden

I didn't realize that the calibration process I suggested could damage the audio interface if the phantom power was not disabled. I think that thread should be deleted as it is very easy to make that mistake. I am surprised I have not made that mistake already. 

Will the Staff please remove it? Link


----------



## Lumen

Lumen said:


> Just wanted to stress that the TRS-TRS connection for loopback _timing_ is crucial for the Focusrite 2i2, which routes phantom power to both XLR inputs simultaneously. AFAIK, The 2i2 will suffer damage if an XLR-TRS connection is used for that purpose, because phantom power will be applied to the output. I learned this the hard way, but it's no longer an issue now that I'm aware.





jtalden said:


> I didn't realize that the calibration process I suggested could damage the audio interface if the phantom power was not disabled. I think that thread should be deleted as it is very easy to make that mistake. I am surprised I have not made that mistake already.
> 
> Will the Staff please remove it? Link


Maybe it's just me, but that sounds like your taking responsibility. I believe your suggestion is still valid. The user just needs to use the correct non-XLR cable for the loopback connection. In that case, it shouldn't matter whether or not phantom power is disabled. Just to verify I understand correctly: the loopback connection on one channel is needed for a timing reference during measurements using the microphone on a different channel, correct? So that means phantom power MUST be on, and an XLR cable should NOT be used for the timing reference (at least in the case of the 2i2), correct?

@OP
You may want to avoid the 2i2 if this issue makes you nervous. There are more details here in my thread here


----------



## jtalden

If my 2i2 can be damaged if phantom power on while the loopback cable is connected that is not good. I presume the situation is similar for many other audio interface boxes. While I am willing to take this risk myself, I am not ready to suggest that someone else to use this method. A simple mistake in the process can be too costly.


----------



## AudiocRaver

Lumen said:


> Just wanted to stress that the TRS-TRS connection for loopback _timing_ is crucial for the Focusrite 2i2, which routes phantom power to both XLR inputs simultaneously. AFAIK, The 2i2 will suffer damage if an XLR-TRS connection is used for that purpose, because phantom power will be applied to the output. I learned this the hard way, but it's no longer an issue now that I'm aware.


The phantom power feed circuit looks like this:









or this









The circuit is balanced, DC-coupled with a 6800 ohm source resistance. Any audio interface output circuit is going to have series coupling capacitors so I suppose it becomes a matter of the breakdown voltage of those caps vs the actual voltage applied across them with those series resistors. Seems like risk of damage is minimal. There will be a thump when Phantom Power is turned on/off, but that alone is not damaging to circuit components.

Edit:

The second diagram above shows the mic preamp input with phantom power feeding the mic itself. Replace the mic in the diagram with the output stage of an audio interface, AC-coupled (probably) and designed to drive high output levels (always). If each of the two balanced output drive devices can handle the 7 mA current (if not AC-coupled), then there should be no problem.

I am not saying it is impossible to fry an audio interface that way. IF you say you did, then you probably did. I would say it sounds like the output stage was under-engineered if you did.


----------



## Lumen

Phillips said:


> Hi please can someone tell me which is the better choice?
> Thanks in advance


If you're still watching it's probably in amusement. I'm sorry for the sidebar that's not really contributing to your decision except to steer you toward the Roland.


----------



## Lumen

AudiocRaver said:


> I am not saying it is impossible to fry an audio interface that way. IF you say you did, then you probably did. I would say it sounds like the output stage was under-engineered if you did.


Your engineering analysis is a relief in the face of what few circuit skills I have. :T

I honestly cannot remember the exact conditions of the mishap, but I am certain it happened while trying to take a loopback measurement. Give a newbie a few instructions and look what happens! A couple years later, I'm ready for some more punishment in time-domain land; so I'll report back if I manage to destroy another one... this time paying closer attention. :R


----------



## JohnM

jtalden said:


> I didn't realize that the calibration process I suggested could damage the audio interface if the phantom power was not disabled. I think that thread should be deleted as it is very easy to make that mistake. I am surprised I have not made that mistake already.
> 
> Will the Staff please remove it? Link


I removed it.


----------



## jtalden

Thanks!


----------

