本帖最后由 SWC0099 于 2023-5-14 21:28 编辑
A Null Test is a definitive way to confirm whether a difference exists between two copies of the same audio sample. Two sample-locked copies of the same audio file are played with one copy phase inverted. If the copies are identical, they will cancel, leaving only residual random noise.
The DUT (Device Under Test) is a Maselec MTC-1X Stereo Mastering Console. No inserts are engaged, just pure transfer between the input and output of the console. Only the power cord was changed. The power cords evaluated included the 18-gauge power cord that was supplied as original equipment, a 14-gauge power cord and a MusicCord-PRO.
Multiple audio samples were produced with each power cord and null tested to establish “baselines”. Then, samples made with different power cords were null tested. The results of the baseline tests for both power cords and of the comparison are plotted together.
Each pairing of “baseline” and “comparative” null test curves reveals significant differences between the baselines and comparavive results over the audible frequency range. In other words, when comparing for example files made when the stock 18-gauge power cord was connected the DUT versus the 14-gauge power cord, the results show significant information did not null out. This is true for all pairings. The null test differences range from 10dB to 20dB! These results confirm that each power cord has a distinct and undeniable impact upon the performance of the connected component. Still skeptical? Download the files and perform the null test yourself.
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