Looking for audio interface to use for audio measurement

[n3mmr]

To this end I need precise and repeatable gain settings in and out, accessible from the unit itself

flat response down to well below 5 Hz and up to at least 40-50 kHz both for inputs and outputs.

32 bit float and all integer bit formats.

preferably multiple microphone/Line inputs

inputs should be extremely forgiving of excessive voltages.

 

[BigIron]

Following with interest. Can I add phantom power to the wishlist?

 

[john61ct]

That's usually a given for mic inputs, preamp includes.

I got 12-port interfaces without those, line level only, very good quality very cheap.

Found rather than dedicated preamps, a mixer was the better value option.

But I assume OP is not skimping on the budget, lots of that wishlist I have no idea which units match

> precise and repeatable gain settings in and out, accessible from the unit itself

to me means not knobs or sliders, but a UI for entering exact numbers, which usually means from a connected PC's keyboard, no?


> inputs should be extremely forgiving of excessive voltages

isn't that what gain control is for?

 

[LTig]

I got the RME ADI-2 PRO fs for measurement purposes, and listening of course. I don't think it ticks all the OPs boxes though, and may be unavailable right now. A better suited ADC should be the Cosmos ADC, and AFAIK one can get a frontend for it which can handle higher voltages.

 

[john61ct]

I believe Cosmos ADC has no ability to master / slave clocks with the output DAC for real-time hardware sync.

There are workarounds, not sure if this applies

REW Loopback Timing via DAW/Software-Routing: Split DAC and ADC locked in time even at mismatched sample rates

If this topic has already been covered, please accept my apologies. My statement below is not based on a deep understanding of REW's internal architecture and does not claim to be definitively correct, but it is derived from the empirical observations described. To the point: If you’ve ever dug...

www.audiosciencereview.com

 

[john61ct]

inputs should be extremely forgiving of excessive voltages.

As a general note, the servo-balancing circuitry in my Aphex 124b balanced <> SE level interface / buffer amp

can tolerate high common-mode voltages from induced hum or interference of over 200 Vrms without sacrificing headroom or damaging the unit.

It can be used as an external gain control, has its own clipping indicator, but also lets you cleanly attenuate a rowdy source to protect whatever interface you end up buying (please let us know)

The Aphex unit is acoustically transparent, but its active buffer circuitry (usually used to convert between low-impedance pro gear and high-impedance consumer stuff) may interfere with your measurements, depending on what it is that you are measuring.

 

[somebodyelse]

I believe Cosmos ADC has no ability to master / slave clocks with the output DAC for real-time hardware sync.

There was a hardware mod to get spdif output which some audio interfaces could use to sync the DAC clock. Apparently hardly anyone used it, so it may not be available in all firmware versions.

 

[n3mmr]

thanks for all the input!

The "forgiving of excessive voltages" was prompted by the need to be able to connect a reference input for speaker measurements directly to the power amp outputs without the need for large series resistors to protect the inputs from mistakes and mishaps. So it's not just for managing large common mode voltages.

48 V switchable on microphone inputs. yes.

John61ct: what 12 port i/f is that???

The in and out frequency response is a problem, since VERY few mfg:s promise much in writing, beyond +-x dB 20-20k Hz for some not-too-exciting x....
And I want to use it as an oscilloscope as well as the heart of a semiautomatic audio measurement setup.
Ideally a switchable DC capable mode for the inputs and reasonable and known levels down to 0.5 Hz for the outputs would only just do the trick, but I would prefer DC capability for outs too.

 

[john61ct]

John61ct: what 12 port i/f is that???

Mostly gear unlikely to interest most, hence why so cheap

As good value for PC I/O as Echo Audiofire 12 ?

Total interface noob here, please ELI5 I don't need to record or mix music in the creative sense, just looking to get multi-channel analog in and out of HTPC type hardware. Primary use case is DIY convolving, loudness contour, bass management, room correction PEQ. The Echo Audiofire 12 unit...

www.audiosciencereview.com

ISO ECHO Darla, Mona, Gina or Layla-24 host adapter cards & cables

From the interface vendor ECHO, specifically the PCI bus (or Cardbus!) cards shipped with the above 24-bit interfaces, also the DB-9 cables Anyone have one or more of these? not those compatible with the OG previous 20-bit versions, nor the later "3G" models. The breakout boxen are commonly...

www.audiosciencereview.com

ADAT interface hosts, high SQ but cheaper than RME Digiface USB?

I am looking for an interface "hub" based on multiple ADAT, clean and transparent. I'm not recording / mixing, just for recreational home DSP - crossovers timing delays / phase alignment tuning Happy to buy secondhand to save money, vintage discontinued no problem. 24-bit, 44.1 / 48kHz is...

www.audiosciencereview.com

ISO cable for OG RME Digiface HDSP CardBus/PCMCIA connection

My goal is not recording or mixing / producing music, but a high count of multichannel DSP and crossovers for recreational reproduction, cheap. If members have other similar gear sitting in closets, or alternative suggestions feel free to speak up. In this case I like the RME OG Hammerfall...

www.audiosciencereview.com

 

[Bamboszek]

What kind of THD performance are you looking for?

MOTU UltraLite mk4 / mk5 with maximum input level of 24 dBu is probably max what you could get.
Too bad Linear Audio AutoRanger is no longer available.

 

[nagster]

To OP:
While it's debatable whether it's an audio interface, for electronic measurements, I recommend the Audio Precision APx555B. If you also require transducer measurements, please add the APx1701 and SW-SPK-RD option.
For detailed speaker measurements, add the necessary modules and options to the KLIPPEL KA3 according to your desired measurements.

Its features are as follows:
- Short time from measurement preparation to report completion
- Minimize operator error
- Comprehensive protection circuits, including overvoltage input, ESD immunity, and output voltage regulation. (I once caused a dummy load to explode...)
- The operator can do other things during measurements, such as checking emails or walking the dog.
- While not a direct function, it allows for easy measurement initiation, quick resolution of questions and assumptions, and confident transition to the next stage.
- It is expensive.

Generalization is difficult when considering the price. Values differ from person to person.
In that case, please also check the DIY thread below. There are more posts about measurements on DIYA.

Measuring Distortion on the Cheap

So, you have a burning desire to measure harmonic distortion and other audio parameters but don't have $40k burning a holes in your pockets so you can buy an APx555B. I have news for you: There are cheaper options. I just finished testing three such options: QuantAsylum QA403 Audio Analyzer...

www.diyaudio.com

For measuring room acoustics, REW and Focusrite Scarlett should be sufficient.