If I may revive this thread for personal use...
At the moment my Coated Amb. heads are nearly 1 year old and at last they sound quite used, especially the 13" and 16". Those 2 start okay but decay with a whoopie cushion sound. I recently started tuning them a little higher than I used to and loved the higher tuning on the 10" and 12".
So here's the main question (s), if I were to switch from my Coated Amb.s to Clear or Coated Emp.s what would I immediately notice? I.E. Would lower tunings come easier? Would I get any extra pitch bend from using Clear Amb. resos? Would higher tunings sound less piecing? Would it maybe work best to only use Emp.s on the 13" and 16" since they seem to be the most difficult? How much quieter would they be? Clear or Coated?
I don't have lots of money to try out a lot of heads so I wanna try to make a decision I can live with for another year.
I have had some
years old (3-4) CA's on one kit also, and it sounds to me the trouble you are having can be solved more by re-tuning the bottom heads.
The old heads I had on that particular kit didn't sound perfect (ha!), but there wasn't a big dip, or wobble ("woo woo woo" with your ear to the head tapping it) or whoopy cushion effect in any of the tones.
I'd check your top tuning to get the pitches where you want them, the make sure the bottoms are reacting WITH that pitch instead of against it. The bottoms can be tuned the same or higher or lower depending on what you like.
If the kit is a few years old, and you have the original, stock heads on it still, replace them.
Emps (clear or Coated) are going to give a deeper tone than Ambassadors, but, a Coated Ambassador can get plenty deep sounding too.
I use them on top and bottom, and they are fat and solid sounding, while being more articulate than Emps. I do like Emps though.
It's all in what you feel like hearing, and what your shells will take to best (to your ears)--which does take some experimentation.
I use 1 ply coated heads, and here are a couple examples of differences on my drums--
Using my regular tuning:
Evans (pre-new 360) single ply heads have a slightly lower pitch in the high end, and, a
slightly less dry character to the initial attack on my drums compared to Remo Ambassadors.
Evans heads sound a bit fatter on my drums than Remo, but I usually prefer the tiny bit drier sound to the Remo, However, the Evans head is a good alternative, if I need a touch more beef, or, maybe a little less sustain in certain tones.
Aquarian just changed their film (to a NuBrite film) and I haven't tried it, but the previous film in a 1 ply coated head sounded thin, and flat for me, but, they sound fat and huge on other drums.... Their OLD film had a fat and solid tone, and a crisp attack to the initial hit. The new film may be more like that.
Try seeing if some bottom head tuning will help before you sink any money into a bunch of heads for now. Hopefully you can get more time out of them.
Hope some of that helped