Usually, you'd look at the Qts. value of the driver. If it is a high Qts rating.. somewhere around .5 and higher, the driver would be ideal for free air use. You can use a driver with a low Qts under .5, but the powerhandling due to mechanical limits would drop substantially. A driver with a high excursion, and a Qts of about .4 would also work effectively in a free air situation. You should just beware of not pushing your driver so hard, it would bottom out.
Ren
