ABX Double Blind Test Results: Digital

ABX Home ABX Hardware ABX Data ABX Literature

SMWTMS ABX Test Results

Digital Audio ComparisonResultCorrectp less thanListeners
Ampex 16 Bit Delay Line vs. wire Same 87 / 160 = 54%0.310

The Ampex 16 Bit Digital Delay Line vs. wire comparison was made in a professional recording studio control room on time aligned UREI 813 speakers with McIntosh MC-2100 amplifiers. The audio source was local country artist P. J. Coombes who had been recorded on a 24-track Ampex MM-1000. That tape had been mixed to a 2-track tape at 15 IPS on a Scully 280. The mixdown and playback was through an API console. Thus the master tape played for these ABX trials was of quality not available to the record buyer of the era.
The listeners included professional recording engineers with years of experience on major label projects, professional maintenance engineers, and recording engineering students.
For those not familiar with studio equipment, these are some of the most revered pieces of equipment of that day. API consoles are still prized today for their high quality. The studio microphone locker included Neumann U-67,Neumann, U-87, and Neumann KM-86 along with various microphones that might be selected for specific applications such as inside the drums.

Different The different symbol means it is unlikely the percent correct score occurred by chance and thus the null hypothesis was disproven, which substantiates a real difference in sound quality.
Same The same symbol means that it is likely the correct score occurred by chance, the null hypothesis is not rejected, which means no difference was found. It does remain possible a difference may be substantianted with further testing.

ABX Home ABX Hardware ABX Data ABX Literature
Send questions or comments on the ABX Web Page to David Carlstrom.

Web Page Created by David Carlstrom. Last Modified: 4/24/2017