Assuming (and boy is THAT risky) that you've corrected the problems with A7 enclosure, and if you only change the woofers and the tuning port size to accomodate the different tuning frequencies, here are the differences between using the 515-G series and the 416-series woofers:

* The 416 will give you better LF response. The 416 works really well in this system when the box is tuned properly. Very linear. Very smooth. It will not, however, go "BOOM BOOM!" - you'll need sub's for that. All things considered, the A7 sounds best, IMHO, with the 416.

* The 515-G series was designed to give the VOTT systems more efficient mid-band response, something that is very necessary in cinema sound. It doesn't have the LF response the 416 has (everything is a trade-off), but it DOES make the speaker more efficient in that critical area of the audio spectrum. The result is a more articulate sounding speaker when it comes to speech - soemthing it was desgined to do - but this feature reduces, in my estimation, the naturalness of the sound when you are in playback mode listening to music. This speaker is my choice in full-range systems where the human voice is the predominant itme you are trying to project to the audience.

The 515-G series, like the 416, will not, however, go "BOOM BOOM!" - you'll need sub's for that.

> In a listening environment, such as the home ir a livesound reinforcement system, and where you are not using subs, I would use the 416 - it will give the most natural, best all-around response in the 825/828 enclosure.

> In a listening environment, such as a livesound reinforcement system, WITH subs, I would use the 515-G series, and cross them over fairly high (depends on the ability of your subs), thus availing yourself of the increased efficiency in the mid-band that the "G" offers in the 825/828 enclosure.

> My personal choice for all-around use, though, is still the 416.

Just my thoughts...