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Post by gouge on Jan 8, 2018 4:24:56 GMT -6
i was hoping someone could give me a some leads to testing preamps.
i've got a preamp i'm doing a mod to and i'd like to test it to quantify the changes.
i've got span although not really used it. i'm wondering about what to use to generate a test tone. any bits of gear i should look at?
tia.
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Post by EmRR on Jan 8, 2018 7:45:28 GMT -6
Many different software packages will do it. Ideally something that lets you capture results.
You want to look at before/after.
You want to use a standard 20dB pad so you don't load down your interface, AND you want to also look at it without the pad. You want to adjust levels accordingly for each situation. Something like -50dBFS pink noise with direct connection, may have to be lower than that depending on the preamp in question.
You want to look at the output loaded and unloaded.
Ideally you want to use something that also shows a phase plot, sometimes audible changes occur that show up in phase which are not apparent in frequency.
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Post by matt@IAA on Jan 8, 2018 11:52:30 GMT -6
RMAA is free, but it has its own issues.
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Post by svart on Jan 8, 2018 15:05:01 GMT -6
A/B comparison is always one of the first things to do. Everything else needs special test equipment. I'd stay clear of the null test trap as well.
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Post by bluegrassdan on Jan 8, 2018 18:12:40 GMT -6
Hmmm. I do like to use sine waves to check harmonic distortion/bias. Run it through an oscilloscope to check square waves for ringing and other anomolies. Also, sweeps using something like Room EQ Wizard.
Those will tell you part of the story. Then, use your ears. Do some consistent recordings - same distance from the mic - perform similarly - real world performance - not laboratory. Match RMS levels in Pro Tools Audiosuite (or whatever DAW). Then send it to your friends and force them to listen over and over!
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Post by matt@IAA on Jan 8, 2018 19:12:15 GMT -6
Hmmm. I do like to use sine waves to check harmonic distortion/bias. Run it through an oscilloscope to check square waves for ringing and other anomolies. Also, sweeps using something like Room EQ Wizard. Those will tell you part of the story. Then, use your ears. Do some consistent recordings - same distance from the mic - perform similarly - real world performance - not laboratory. Match RMS levels in Pro Tools Audiosuite (or whatever DAW). Then send it to your friends and force them to listen over and over! REW is a great idea. |
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Post by gouge on Jan 9, 2018 15:27:07 GMT -6
Thx guys.
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Post by kilroyrock on Feb 2, 2018 18:46:40 GMT -6
I picked up the behringer cable tester, it has a built in tone generator and now I can test my cables quickly too!
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