yep the g12t-75 has more of mid scoop with top end sizzle. The v-30 has a full warm mid range.
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for some of the best prices on eminence and celestion speakers. Usually the higher the wattage rating on a speaker the more the lows and low mids are thrown out but magnet and overall construction play a huge part to that as well also effiecency of the speaker.
i didn't like the x2n too much for the fact that it was hard for me to get a thick chuncky sound out of. The d-sonic is great for depth and clarity, the breed is too which the dominion is based on. It is almost impossible to get a shrill sound out a breed but the clarity is amazing.
It sort of depends on if you are going for more of a smooth big bold mid range or a chuncky crunchy thick mid range.
I have also never been much of fan of ruby tubes or ehx. As an experiment swap around your pre-amp tubes to see if you dont notice any change. It doesn't cost any money and can make a fair amount of difference. ( especially in the V1 slot)
You may also consider getting something like a 10 or 7 band EQ.
As stupid as it sounds and i am certainly not insulting you by saying it but check the owners manuel for recommened sound settings. I have ragged on amps that i thought were junk only to come back to them later and figure out i love them. I was just not setting them right.
most peavey amps(xxx, jsx, 6505) i turn the res up to around 7, the presence down to about 3, 5 or 6 on the highs, around 8 on the mids and 8 on the lows about 7 on the gain. Does the trick most of the time.