You are absolutely right in that you should steer
clear of th 700 MHz area. Any investment in that part of the spectrum will be money wasted. $7000 for 15 mics is a little on the low side when you begin to consider all of the important factors of a well designed wireless
system. With that many mics you will need a frequency agile
system, proper antenna combination / distribution, and proper frequency coordination for your specific location (just to name a few key considerations). Be sure to do your homework in this area and do not cheap out. Running that many wireless systems at once can snowball very quickly. It is always preferable to have fewer quality systems in a package that is well put together, than many systems that fall apart in a year or two.
You may want to look into the
Shure SLX wireless systems with the WL93T mic elements. They are not the top of the
line, but they are a decent mid grade option. We have had 16
in one of our venues for almost 5 years now and have been real pleased with them. I am not certain what
current pricing is on them, but they are the closest product that I know of off the top of my head that I can vouch for by personal experience that will fit your budget (or come close). I am certain there are others though.
After a cursory look at their website, it looks as if the
Sennheiser system you mention should be able to offer enough variety in frequencies to get 15 working systems with several alternative available frequencies to tune to in case "issues" develop. Looks like they are running about $600
unit not including antenna and
power distribution, a rack, spare mic elements / transmitter, or anything like that, so they may be out of reach of your
current budget. Certainly worth checking into though, you never know what pricing a dealer may be able to offer with a bigger
purchase like this. Most manufacturer are offering rebate programs if you turn in a 700 MHz
system and buy a new
system from a dealer, so that will certainly help your cause if you act in time and the
Toa systems qualify.
~Dave