Hi,
The only points I am making are:
The drivers are brand new made less than 30 days ago, that they have a low frequency specified rating of 300Hz,
and that they were reccomended for my application.
And yet at the very low power that I operate them at -less than 90dB measured at the horn mouth- they are producing a signficant "double tone" at all frequencies below 1000hz
also, as you lower the level down, you hit a point where a "chorus" of tones appear.
Both drivers do this, so that to me indicates that they are defective in some way.

I am unable to accept this as "normal" operation.

Perhaps if I were running these at very high levels, true resonances - that are the result of build design- will apear, but I would not expect that at these low levels.

Kevin
010311