C.R.E.T 

(Converter Round-robin Evaluation Test)

Hi I’m Fabian and welcome to CRET, our advanced converter evaluation. Let me explain what this post is all about: In this post we will post data plots that I personally will analyze and comment from user submissions following the CRET protocol explained Bellow.

I have researched and consulted some of the best professionals, to come up and tweak this method to a user friendly doable way.

The test you will be performing is called a round-robin, and it refers to utilizing an output of a system and an input simultaneously.

 

  • What CRET is: A user friendly protocol for generally evaluating a converter unit as a sum.
  • What CRET is NOT: A replacement for top notch professional converter test and by nature it cannot be. We have to mention that a fully optimized converter test is extremely expensive both in personnel and gear to perform.

 

HOW TO SUBMIT YOUR CONVERTER & UTILIZE C.R.E.T

 

STEP GUIDE:

  1. Download and Unzip CRET Tones: https://copy.com/6FVBnxGOQq6QjaLB
  2. Import ”CRET CALIB” file (from previously downloaded tones) into a 44.1/24 bit project you create, in your DAW. 
  3. Set a desired physical output for CRET CALIB, and physically connect that output to a desired physical input of your device. (please use the best trs-mono cable you have available)
  4. Create a new blank track, that has the physical input you choose before as an digital input (set no output) arm the track/monitor enable it and then playback –  you should see your meters working that are being fed from your first CRET CALIB track.
  5. Make sure your device buffer (if can be changed) is equal or above 512
  6. Open a Meter plugin in your second track (the one you have armed) and set your physical input gain to match -0.1 dBfs on your digital meter/device pane (if any), since such precision might be difficult with some knobs/units you can go a bit lower between -0.1 and -0.5 dBfs.
  7. After calibration is complete, delete the CRET Calib file but keep the daw track we used.
  8. Now in our first track drop CRET THD and record your second track
  9. After recording is completed offline export only the second track by selecting it from the appropriate daw menu or activate the output and export real-time. (Export must be mono 44.1/24 bit)
  10. Delete CRET THD file (keep the channel) and replace with CRET FR, repeat recording and export
  11. After the two test files have been exported. Zip/Rar them into one archive naming the archive exactly like your converter, e-mail your files to [email protected] for further analysis and publication.

 

  Edit ContentIs CRETs analysis software.

Thanks to Paul Frindle for his amazing insight and consultation.

Glossary & additional info: https://www.gearevu.littlefishaudio.com/must-read-welcome-to-my-lab-updated/

 

SUBMISIONS

 

Focusrite/Saffire Pro 40

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FR

(Input step stages)

MAX – MID – MIN

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Here we see a three point FR, the sum of the analysis leads that the response can be considered flat, the fluctuations that occur are minimal. Bellow you can download a TXT file containing all Frequencies with their relative magnitude from the published plots.

  • https://copy.com/xRuXCTmlYUOao92K  MAX
  • https://copy.com/NFA2anqpL3ZPu6To  MID
  • https://copy.com/iTlnm80FRq8KbvWk  MIN

 

THD/THD+N

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In this plot we can observe the unit distortion in stages from MAX to MIN and last frame is a standby when no audio is running. What is worth noting is that the unit distorts generally at higher amplitudes and has some artifacts below the fundamental as well, Distorting in a higher amplitude register is generaly a good feature but the artifacts below the fundamental are not (which are on the low side in this unit) and classifies the THD response in relation to the FR Between Good and Excellent.

Especially when we must consider that this plot is derived from a round robin method!

 

Apogee Symphony I/O

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FR

(Input step stages)

MAX – MID – MIN

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FLAT

You can download a TXT file containing all Frequencies with their relative magnitude from the published plots.

  • https://copy.com/1UWcLLt3Q9vogifY MAX
  • https://copy.com/n1jTwep4XBLtBhEe  MID
  • https://copy.com/e83QPXnnjXamrl1h MIN

 

THD/THD+N

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Excellent, the little distortion that happens its at the highest amplitude register also no artifacts below fundamental.

 

BLA MOTU 896HD (Black Lion MOD)

 

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FR

(Input step stages)

MAX – MID – MIN

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We see some FR fluctuations but in general terms it can be considered flat

You can download a TXT file containing all Frequencies with their relative magnitude from the published plots.

  • https://copy.com/3ErmadNFIjYulMZV MAX
  • https://copy.com/iAJlLNsX9EDrb0sS  MID
  • https://copy.com/q6VnG6PqQnqz1iIK MIN

 

THD/THD+N

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We see some major static artifacts below the fundamental which is a bad thing, we also see distortion in all stages not in an extreme percentage but the fact that they don’t go away is also a bad thing aswell.  As far as categorizing I’d give it a below Good classification. 

Q: Why would you do that ?

A: There are three scenarios that (one of them) is bound to be valid with the CRET, one is either input distorts and output does not, two both distort and get summed, or three only output distorts. 

Any of those especially in the pro field must has some degree of transparency so if any of these scenarios is the case , its still bound to the classification.

 

SPL – Madison

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FR

(Input step stages)

MAX – MID – MIN

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FLAT

You can download a TXT file containing all Frequencies with their relative magnitude from the published plots.

  • https://copy.com/wt72ybihn360r70G  MAX
  • https://copy.com/YkuNZD4Tz2QH7lkz  MID
  • https://copy.com/Jg7VZyiAYKuy1vL4  MIN

 

THD

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What we can observe is that the distortion of the unit tends to increase closer to the higher amplitudes while containing a generaly clean profile, with no additional artifacts whatsoever! Somewhere above good and below Excellent based on the overall sum, but definitely excellent on the mid to low register.

 

Apogee Ensemble

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FR

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(Input step stages)

THD

 

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Excellent results! Both in FR and THD. We can see the converter reacts when pushed, yet its distortion values are quite low, no artifacts (except that small spike at the end, wich might be the result of static). In general terms the response is quite transparent and flat!

 

 

 SUBMIT YOUR CONVERTER WITH CRET, TODAY!

 

 

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