AD converter test suggestions ...

[Adebar]

For me it is easier to hear differencies between converters by recording/replaying a stero pair of microphones for an orchestra than comparing the sound of single instruments. The same with a stereo mix coming from analog tape or the mix bus.

Differences often appear in the depth of field and the dynamic structure of a mix or a stereo mic pair.

[idee und klang]

Originally Posted by rob99

Hello

I have ordered a new high end AD converter.

Want to test it and need suggestions for what would be, in your opinions, the most challenging/revealing sources that would push the limits of its conversion?

Are there subtle sounds or decays that converters have an obvious problem converting?

I am looking for general suggestions to reveal the great ideas that I usually miss.


thanks

rob

I made converter tests many time, and it is not easy. First of all imo it is important that, if you compare two AD-converters, you feed both of them with the very exact same signal and calibrate them as good as you can with a test tone generator. Test like a singer sings one take in AD1, then one take in AD2 do not work at all, most likely one ends up to find the converter where she sung the better take better.

Alway test with stereo sources, as it is far more easy to hear the differences. A Guitar , A Grandpiano , and Cymbals are good things. Hear for the image and depth of field, and natural sound. Very cool fo check details is to record a bunch of keys.

I would splitt the ouptut of the micpreamplifier (on some a Y Cable is ok, some need impedancematched splitters) and then feed both converters.

Listening must be totally blind

Daniel
www.ideeundklang.com

[Dave Peck]

Apologies if I'm stating the obvious, but the most important thing is to use a source that has never been digitized. Even using a 24/192k source will greatly reduce the likelyhood that you'll hear any shortcomings of the unit you're testing.

So your options are things like a high-quality first-generation analog recording of a source with lots of transient details and accurate stereo acoustic ambience, like a simple stereo mic recording of an acoustic guitar in a good room or a minimal-mic recording of an orchestra in a good room, or a live feed of the same signal instead of a recording.

Next issue is - what are you comparing it to? If you just want to know how much the A/D is affecting the sound, one technique would be to set up an A/B/X box that sends the analog signal straight through to the output in one position, and routes the signal through your A/D and D/A chain in the other position. Note that this means your D/A device is also part of the listening test, which can be good or bad. If you notice differences when switching between the analog source and the A/D-D/A chain, you'll need to determine if it's the A/D or the D/A that is responsible for the difference.

But if you just want to know if you like the sound of this A/D box compared to another A/D box, regardless if it is accurate or adding coloration, you can set up a different A/B/X chain that switches between the outputs of two A/D boxes and routes them both to one D/A device. This test is more subjective, because it doesn't tell you anything about how much either converter is changing the sound of the original analog source.

Dave Peck

[rob99]

thanks folks for taking the time to reply.

Nothing is obvious ... with the varied experience of the GS members, I always learn something, and at the best of times, have my basic assumptions corrected.

I will not be comparing AD's, just putting mine through its paces.
I have ordered the new Digital Audio Denmark AX24 and was thinking of posting samples from it. But I don't have a server.

thanks

rob