I wouldn't say essential. Depending on how you have your live show set up you can get away without one, some of the variables being:madtheory wrote:Ya, it's an essential part of a gig rig. A rack with a mixer, effects, and maybe a few rackmounting synth/ sampler modules also.
1. The size of the venues you're playing ie. what gear your engineer is going to have access to. Most places we play have a D2 and at least a couple of M1s so we don't have to worry about it.
2. The lineup of your band. If you've got three vocalists and a live drummer you'll probably need to use the FOH verb on them, if you're instrumental and just synths the FOH fx will be available for you.
3. Where you want your synths to sit in the mix. If they're sitting low in the mix onboard fx can work, or you could share a verb with another instrument in the mix.
When we used to play live we had 5 or more synths and an MPC on stage, all going to a stage mixer and some fx. Now that we're a two-piece (from 4, even 5 for a while) we've ditched a whole lot of the gear and just have two synths on stage going through some pedals (MEK -> RE-20, Micron -> Crybaby -> Small Stone -> Digital delay) and things sound a lot better than they used to. I seriously think that a lot of bands sound worse live than they should because it's hard to mix and play at the same time, and you can't hear the FOH properly anyway.
Then again if you're in a 5 piece rock band and you have a couple of synths your FOH engineer is going to have their hands full mixing the whole band so it could make things easier if you just send them a stereo mix of your stuff, with fx. Just remember to do a proper soundcheck so your engineer can let you know if you've got too much verb on your mix or whatever.
This is advice from someone who's played and mixed hundreds of shows, and learnt quite a few things the hard way.