I've begun a Acoustic Test CD project that will contain various test tones, solo drum tracks, bass lines for testing your subwoofer and other musical tracks to test the rest of the frequency range and stereo imaging. Apple's Garageband will handle all the music compositions while Amadeus II will output test tones. This collection of tracks will follow industry experts' and my own philosophies and techniques for getting the most music out of your stereo through proper acoustic set up.
The project is born out of frustration. Every time I read an interesting method for evaluating my stereo components, the author references some audiophile jazz or classical CD from the mid-90s that has one track to set my sub level by. Like in this Bob Katz subwoofer setup article:
Rebecca Pidgeon, The Raven, Chesky JD115, available at record stores, high-end stereo stores, or from Chesky Records… I recorded Rebecca's disc in 1994. Track 12 is Spanish Harlem, which has a slow, deliberate acoustic bass part that makes it easy to identify notes that "stick out" too far and covers the major portion of the bass spectrum. This record has never failed to reveal the anomalies of different rooms and loudspeakers in several years of use as a musical reference… Spanish Harlem, in the key of G, uses the classic 1, 4, 5 progression. Here are the frequencies of the fundamental notes of the bass. If your loudspeaker has sufficiently low harmonic distortion, it will not affect your judgment of the power of the bass notes, which are already affected by the natural harmonics of the instrument. 49 62 73 65 82 98 73 93 110 As you can see, this covers most of the critical bass range.
So, instead of going out and finding a CD I know I won't like, I decided to create my own "Upright Jazz Bass" tones at those frequencies in Garageband. I asked my musical genius cousin, David, to explain a "classic 1, 4, 5 progression in G," he kindly wrote down the notes so I could "play" them on Garageband's MIDI keyboard. I got the first frequency sequence right (after checking its sonogram signature in AudioXplorer), but the two higher 1, 4, 5 sequences were wrong. I'll have to check his note again. Recreating this bass line is just one example.
I'll continue to pick out audiophile review and advice referenced recordings and recreate the important parts in Garageband. I hope the application's instruments have the needed fidelity to reveal sonic differences in at least my own system if not your own. Here's a potential track list:
- 1/3 octave test tones (maybe even compensating for the Radio Shack SPL Meter's short comings like the Rives Audio Test Disc)
- Wide and limited bandwidth pink noise
- Drum tracks with extended kick drum, snare and cymbal solos
- Drum kit tracks mixed with an electric bass guitar
- The acoustic bass mentioned above in the Bob Katz article
- Other instrumental solos based on common audiophile review listening test music selections
I'll try to pack in as much material in the disc to save you from having to buy too many commercial test and music CDs. Each track will have a complete explanation of its purpose so you know what to listen and measure.
When I have a full disc worth of material I'll offer it on the site. Not sure if it will be a standard CD, DVD-(A?), individual tracks for download or all of the above.
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