Advertised constant-directivity specs often cover a band irrelevant to speech intelligibility.

Evidence

However, beware of specmanship. One of the authors has seen a loud­ speaker advertised as having a constant directivity of 90°  60° using a horn whose mouth dimensions were 130  130 mm. This gives an Fθmin of 2.4 kHz and 3.4 kHz respectively. As most human speech energy is between 100 Hz and 5 kHz this speaker’s directivity is going to have very little influ­ ence on the intelligibility of the speech! — David Howard, Jamie Angus, coustics and Psychoacoustics, 2497

Categorization

• CANDY: A great elevator fact: a ‘90°×60° constant directivity’ speaker whose pattern only kicks in above 2.4 kHz, where almost no speech energy lives.
• SEED: Essay angle: how specsmanship in audio gear lets manufacturers claim specs that are technically true but acoustically meaningless to the buyer.