Bass and room modes test with music CD
If you are frustrated by playing with a Rat Shack meter and test tones (frequency tones, warbles, pink noise, 1/3 octaves etc.) and never quite sure what you should "fix" or what you should just live with (no room is ever perfect)....then this may be the CD for you.
Rebecca Pidgeon, The Raven, Chesky CD.
What follows is taken from Bob Katz excellent book on Audio Mastering. The track "Spanish Harlem" on this CD, in the key of G, uses the classic 1, 4, 5 progression. Here are the frequencies of the fundamental notes of the bass.
49......62......73
............65..........82.......98
....................73..........93..........110
Check it out.
In the absence of a test CD with real music I spent hours playing with test tones/Rat Shack meter/PEQ... and initially I went overboard with a PEQ trying to fix everytyhing as near flat as I could in the LF. In the end, I did not like the sound when it was equalized flat and went back to a minimal PEQ approach with a few minor adjustments on the worst offending peaks but never crushing the sound into conformance. (trial and error process playing many CD's)
Yesterday I received the above CD and played Spanish Harlem track. WOW - it works. You can easily HEAR immediately how balanced it is. (Real notes on a real instrument seem far easier to balance in your head than test tones...I can't explain why but that was my experience...perhaps it's the harmonics)
I realized that this CD could have saved me an enormous amount of time.....it lets you judge how the room modal bumps, incorrect sub settings and/or placements are actually affecting a real instrument.
Unlike the Rat Shack meter this allows you to gauge the amount of tweaking necessary. For me, a 3 db bump over a 6 Hz interval is much better simply left alone rather than mercilessly PEQ for flat reponse; but a 10 db bump is an audible intrusive problem clearly affecting the balance. In any case, the CD lets one precisely judge the relative effects on music.)
IMHO, PEQ adjustment to get a flat response, whilst easy to do, is far from ideal because it adjusts the primary signal in order to get the combined primary and room modal signal down (the room modal response is the real culprit and, although not always practical, room treatment/design is by far the ideal solution)
...just thought I would share this. Any comments from anyone who faced this issue or perhaps has found another solution or another good test with music CD?
