Ok so I've already got myself a very good microphone for acoustical measurements.
However the standard laptop soundcard is utterly crap you could say.
With an external microphone preamp and amplifier I was able to do some measurements using REW as the software.
Problem is that it is kind of a hassle to get everything hooked up.
So I was thinking about getting a setup together in a 3U flight case that I can take with me and can be used to do some audio/acoustical measurements.
I have also seen ARTA software wich looks really nice to also do some impedance measurements.
I currently used the Dayton DATS V2 for this and this works but would be nice to do some measurements at higher power.
SO first things first I would need a USB audio interface. 19" if possible and would be nice if it has some ADAT capability. (I need to test/repair a lot of gear so this would be usefull for testing gear with ADAT interface)
After some searching I came across teh following:
Behringer umc1820 UMC1820 | Interfaces | Computer Audio | Behringer | Categories | Music Tribe - Behringer)
Price is very low for what it has to offer.
I'm not the greatest fan of Behringer. Bad build quality etc.... (altough the DCX2496 did impress me)
Next up is the Focusrite Scarlett 18i20 | Focusrite
A little bit more expensive. Has higher available sample rate.
The extra input display is also nice as an indication to not overload things....
Ok the extra inputs are overkill for just acoustical measurements but it is the only one that has Adat and it would be nice if I can use it to test some Adat gear.
So next up I would need an amplifier, Resistor to measure impedance and then some connectors/switches frontpanel etc.....
So I have a UCD400 module lying around that could be used as an amplifier. Have some spare transformer somewhere also.
Don't know if the switching noise residue would be problematic for measurements.....
The high impedance inputs of the interface could also be used for some distortion measurements of preamps etc....I do have a Audio precision for that in my lab but it is not that portable for when I need to do some measurements on site.
So any advice is welcome.
I have seen the QA401 and QA460 wich I like but I Wouldn't have ADAT then.
However the standard laptop soundcard is utterly crap you could say.
With an external microphone preamp and amplifier I was able to do some measurements using REW as the software.
Problem is that it is kind of a hassle to get everything hooked up.
So I was thinking about getting a setup together in a 3U flight case that I can take with me and can be used to do some audio/acoustical measurements.
I have also seen ARTA software wich looks really nice to also do some impedance measurements.
I currently used the Dayton DATS V2 for this and this works but would be nice to do some measurements at higher power.
SO first things first I would need a USB audio interface. 19" if possible and would be nice if it has some ADAT capability. (I need to test/repair a lot of gear so this would be usefull for testing gear with ADAT interface)
After some searching I came across teh following:
Behringer umc1820 UMC1820 | Interfaces | Computer Audio | Behringer | Categories | Music Tribe - Behringer)
Price is very low for what it has to offer.
I'm not the greatest fan of Behringer. Bad build quality etc.... (altough the DCX2496 did impress me)
Next up is the Focusrite Scarlett 18i20 | Focusrite
A little bit more expensive. Has higher available sample rate.
The extra input display is also nice as an indication to not overload things....
Ok the extra inputs are overkill for just acoustical measurements but it is the only one that has Adat and it would be nice if I can use it to test some Adat gear.
So next up I would need an amplifier, Resistor to measure impedance and then some connectors/switches frontpanel etc.....
So I have a UCD400 module lying around that could be used as an amplifier. Have some spare transformer somewhere also.
Don't know if the switching noise residue would be problematic for measurements.....
The high impedance inputs of the interface could also be used for some distortion measurements of preamps etc....I do have a Audio precision for that in my lab but it is not that portable for when I need to do some measurements on site.
So any advice is welcome.
I have seen the QA401 and QA460 wich I like but I Wouldn't have ADAT then.
For speaker impedance measurements I would prefer a conventional class AB amp with +- supply. This eases the way to measure speaker current.
I share your opinion concerning Behringer, but their soundcards seem to offer much value for the money.
Whenever you want to measure a bridged amplifier you will need a symmetric line input.
Focusrite are quite common now, I would call them good mainstream but a bit pricey.
A used EMU is in the same ballpark for less money.
There are some ARTA hardware sets on the market that provide speaker impedance measurements.
I share your opinion concerning Behringer, but their soundcards seem to offer much value for the money.
Whenever you want to measure a bridged amplifier you will need a symmetric line input.
Focusrite are quite common now, I would call them good mainstream but a bit pricey.
A used EMU is in the same ballpark for less money.
There are some ARTA hardware sets on the market that provide speaker impedance measurements.
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I don't see any reason to use the UMC1820 or 18i20 unless you want to repurpose them later as a DAC + ADC and to DSP on the computer (which I do). In that case, choose the Behringer (I own two of them).
If you only want a dedicated USB interface for measurements, I would look to Focusrite e.g. Scarlett 4i4 or even better but more costly Clarett 2Pre. I get the idea you need a mic preamp and phantom power supply, and so I would look for a unit that has its own power supply and is not USB bus powered.
One very nice and relatively new option is the MOTU M4, however, it is bus powered. For the price it has fantastic performance, but is not widely available and currently not supported under Linux (but has a Windows driver). Linux support is available in the latest kernel release but you won't get that with your OS and you will have to try and upgrade the kernel yourself.
Keep in mind that you CAN make distortion measurements with this kind of gear with a limited bandwidth up to 96kHz. This is NOT a substitute for an AP or a scope except at these low frequencies. To make amplifier measurements you will want a "jig" that protects the inputs from overvoltage, reverse voltage, etc.
Also, this thread might be of interest to you:
USB Audio interface for measurement
If you only want a dedicated USB interface for measurements, I would look to Focusrite e.g. Scarlett 4i4 or even better but more costly Clarett 2Pre. I get the idea you need a mic preamp and phantom power supply, and so I would look for a unit that has its own power supply and is not USB bus powered.
One very nice and relatively new option is the MOTU M4, however, it is bus powered. For the price it has fantastic performance, but is not widely available and currently not supported under Linux (but has a Windows driver). Linux support is available in the latest kernel release but you won't get that with your OS and you will have to try and upgrade the kernel yourself.
Keep in mind that you CAN make distortion measurements with this kind of gear with a limited bandwidth up to 96kHz. This is NOT a substitute for an AP or a scope except at these low frequencies. To make amplifier measurements you will want a "jig" that protects the inputs from overvoltage, reverse voltage, etc.
Also, this thread might be of interest to you:
USB Audio interface for measurement
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Having the ability to use it also for some portable recordings etc... is a benefit also...
The main problem with the smaller focusrite interfaces is that they don't have Adat. As I also want to test gear with Adat connection.
The main difference I see between the 2 is that the focusrite has 192khz capability. would be better for some distortion measurements....
I don't need phantom as my measurement mic has it's own supply of around 200v.
Going to look at some ways to protect the inputs of the interface.
When using high power amps I will certainly need a pad to get the signal down. some protection diodes wouldn't be a bad idea either
RME ADI-2 Pro Fs R is a very good measurement interface. It has high power headphone outputs with very low output impedance that work well for impedance measurements. At its 384 kHz sample rate the analog input bandwidth is 180 kHz. It is half width but RME sell rack mount adaptors for it.