I've used the TAD 4001, and found that it does benefit from top octave compensation, but not as much as the JBL 2446. Some people use the TAD 4001 on horns that provide enough EQ acoustically, but this means that polar response suffers. For stereo HiFi use, I prefer to use horns that have collapsing DI in the vertical and a constant 90° coverage angle in the horizontal axis. This provides a good compromise solution, requiring less electrical EQ and making compensation fairly simple.