I'm thinking size of the room, volume of said drummer, two guitarists and your current gear. It seems almost impossible, IMO, to get the sound you want with those constraints. It's like saying you want a tight dub-reggae bass sound in an airplane hangar.
New gear or almost any gear I can think of is not going to solve this issue or your quandry. Keep in mind this IS practice, and isn't the show. Your "tone" IS going to get swallowed up, and really the best thing you can do, cheapest, and simplest is to briefly (for the length of the practices) suspend your pursuit of the ideal tone, and set your knobs and eq to cut through, even if it sounds metallic and clicky- knowing that during the show, you'll be able to set the tones as you want, and get them. THAT is where the tone really counts. Remind your bandmates of this too.
I hate to be snippy here, but if you can't cut through with a 4*10 combined with a 15 cab, things ARE way too loud, and your room simply cannot handle that level of volume without turning into utter mud and muck for the low end, and probably for everything else too. The whole group needs to either play a lot quieter, or else get a bigger room. I think you could have two SVT stacks (or pick your loudest amp) and it will neither sound CLEARER or BETTER. It will only be louder.
Please realize that there are a lot of cool, great options available to us bassists, but changing the laws of physics and proximity effects of so many loud things all going on at the same time, unfortunately is not yet one of them.
Best to you.
New gear or almost any gear I can think of is not going to solve this issue or your quandry. Keep in mind this IS practice, and isn't the show. Your "tone" IS going to get swallowed up, and really the best thing you can do, cheapest, and simplest is to briefly (for the length of the practices) suspend your pursuit of the ideal tone, and set your knobs and eq to cut through, even if it sounds metallic and clicky- knowing that during the show, you'll be able to set the tones as you want, and get them. THAT is where the tone really counts. Remind your bandmates of this too.
I hate to be snippy here, but if you can't cut through with a 4*10 combined with a 15 cab, things ARE way too loud, and your room simply cannot handle that level of volume without turning into utter mud and muck for the low end, and probably for everything else too. The whole group needs to either play a lot quieter, or else get a bigger room. I think you could have two SVT stacks (or pick your loudest amp) and it will neither sound CLEARER or BETTER. It will only be louder.
Please realize that there are a lot of cool, great options available to us bassists, but changing the laws of physics and proximity effects of so many loud things all going on at the same time, unfortunately is not yet one of them.
Best to you.


