Yeah, well, I read everywhere that rhythm guitars should be dry as a desert.
And I personally prefer delay then reverb. But it depends.
And for pads like the warm pad I tend to pan very closely to the center otherwise it gets too big imho.
For something more like a squarish lead I tend to treat it like a lead guitar and I usually put 2 different sounds. There is this one song where it is a squarish minimoogy lead around R45 and a polysynth for the same part at around L45. And I tend to pan the lead guitars at L and R30.
Orchestra hits and timpanis I pan near the center.
Strings I use 2 sounds and pan them around L and R60. Btw I use stereo sounds 90% of the time. And for the 2 string sounds I use one more airy, with not a lot of attack, but it's like, dreamy? And the other has a lot of attack and much dryer. I put distortion in the "attacking strings" because otherwise they sound too clean to my taste. I enjoy strings like Sirenia and Tristania more then... Kamelot? And I don't try to recreate a real orchestra, I just want a cool sound.
But of course it all depends. Sometimes I use sitar as a rhythm part and sometimes as a lead part. I won't treat them the same. And with guitars the rhythm are hard left and right and the leads closer to the center and I tend to do the opposite with the synths. Except for the strings.
And it seems there is a very big imaginary mental thing to take into consideration. Like, metalheads want BIG guitars and smaller synth sounds 99,99% of the time. But a string orchestra is much bigger then a guitar player IRL. So for me, who is a keyboardist before anything else, must be careful with that. You don't want a piano to be bigger or fuller or richer or then metal guitars. ( my vocabulary might be pretty poor btw ). So usually for piano I take off some low frequencies. And for the piano I use to think I should put a lot of reverb but now I much prefer to put no reverb but I increase the release. I think it sounds less muddy.
For harpischord, I do something similar. And if I want those 2 instruments to sound more "space" after I put delay. But if you put too much release it will sound muddy as hell.
I love "bright/crystal" kinda pads and I adore how they sound in Eternal Tears of Sorrow's album A Virgin and a Whore. You cannot really make out all the notes even though the part seems not very easy, but it's so everywhere and not over the metal band that, dunno, I never reached their sound.

But I guess they use a pan lfo ( which makes the sound go left to right ) with delay and maybe other stuff. yeah.

Stuff is cool.
I don't like rock organs and other types of organs except the church organ. I think church organs are real bitches.

The volume of playing one note is usually veeeeery different then when you play a chord. And usually church organs sound too wimpy. So I add some distortion and take off some low frequencies otherwise it may sound more bassy then the bass.
I like harp.

Again, I take off some lower frequencies and I don't put reverb, I put a bigger release. And if still dosn't sound spacey enough, delay. And if I think it sounds too harpy ( sometimes it happens with a harp ) I put another sound, like, some sort of bright/crystal pad thingy.
Brasses also suck usually. Only one sound of brass sucks ass big time. It never sounds like the big brass ensemble trumpeting something before the soldiers march or something. They usually sound like fisher-price games even when you paid a lot of money for it. So I put 2 or 3 different type of brass. Usually I compose more lead parts for such sounds so I tend to go more with trumpet sounds then tuba sounds. But if I want to go all the way with it and the darn brasses are very important in the song I will duplicate the track, transpose it into different octaves, use trumpets, tuba, trombone and a french horn. Sometimes add distortion to one of the highest parts to add some attack and aggressivity. And if the brassy part is less important in the song I will duplicate one or two times depending and will use 2 different types of trumpets. Sometimes I add a polysynth to add some body.
And etc, etc. I read somewhere on this forum in a drum topic that if you want your toms to sound higher and your kick to sound lower ( stereophonically ) you have to lower the low and higher the highs to make it go up and the opposite to make it sound down. And usually metal bands want the band under and the synth higher.
And I think that if your guitar, bass, drums and vocals sound AMAZING and modern and all you can make some synths sound like they are coming out of a 1953 radio.
So basically, from my point of view, there are rhythmic keyboards, leads, and percussive.
And when I say percussive I mean timpanis and orchestra hits, nothing wimpy. :Smug: Rhythmic close to the center, percussive also, and lead more out.
The way I compose strings it would be too big of a hassle to select which part is rhythm and which is lead. But since I already have my airy string AND my attacking strings then I can also simply mute one of them if one part has too much attack for example, or vice-versa.
If one sound sounds too little, wimpy, boring, fragile and bleh I duplicate and put another sound.
If it makes the song sound muddy I remove some low frequencies.
If I think there should be reverb I put a bigger release. If I think it's still not spacey enough I add delay.
I use to be a big fan of reverb until I realized it usually sucks.
For the percussive I tend to make them mono, like a drum track.
For the rhythms I use mostly stereo. Especially for pads where the sound evolves. When the sound evolves = stereo necessarily.
But if for a rhythmic part I had the "great" idea of using a harp and a sitar together, there are good chances they will be both mono.
For lead parts it depends on the sound and plugin. And I personally prefer when it feels like the synths are coming out of this place :
http://www.photoshoptalent.com/imag...e/fullsize/old castle_4762d3407a25b_hires.jpg
Instead of this place :
http://www.dent.unc.edu/depts/academic/ped/images/clinic.jpg
So some distortion can be cool for that. I never tried the TSS on strings but now that I think of it, it should be nice. And I never tried the church organ in the boogex. I am not a mega pro you know.

But I spent more time playing with vsti then real instruments.
And if you want that tututukutatakata techno'ish sound bands like In Flames and Soilwork seem to be using ( or like Needled 24/7 from COB I guess ), the idea is to get a squarish/rectangular lead sound and automote the osciallators of your choice. Or get absynth and do stuff with it. And here is what MC Raaka Pee from Turmion Katilot says he used for the album USCH, which totally kicks many asses.
I used logic's softsynths in this album, instead of hardware. You cannot find the sounds from presets, because they all are made all over again from the first waveform to the last. Anyway in Pakanamaan Kartta: only ESX24 Sampler (5 different patterns), and ES2 (4 different sound variations). So the synths are in 9 tracks. In live Run-Q uses Korg Triton Extreme.
And another song with super cool synth sounds.
[ame]http://www.youtube.com/watch?v=INUu_dUlXDI&feature=related[/ame]
And here is Sirenia whom I mentioned, and imho not all their songs/albums are good, but they are the ones who made me think my strings should probably sound more like a 1953 radio :
Tristania ( with a very bad sound ) :
Eternal Tears of Sorrow ( intro with the bright/crystal kinda pad )
It's been a while I didn't listen to that ETOS song and now I hear piano in the darn bright pad! pfft.

But there is a pad in there with delay!
Those are some of the types of synth sounds ( and philosophy? ) I love.
So yeah, that's my gibberish for the night. And btw it is possible that I may think differently in 6 months or so.

And I'm sure some people know much more and are way better then me.