oops wrong thread.

I took a look at that Iris 2 thingy, now kinda wished I hadn't, LOL!  It's on sale for $126 right now.  Already blown my budget for this month, so will have a few new features to add to my Synthmaster V3 wish list!  Need to go post over on KV331's forum!
 
Iris 2 is a sample based synthesizer with a killer workflow for building sounds from scratch quickly.
 
I really like how Iris allows spectral filtering of multiple wave samples, in both dimensions of time and frequency.  Take a little part of one sample and blend it with part of another, and so on.
 
The graphic display really shows what is happening, and you can see the waves in a timeline type view like a DAW.
 
By comparison, Biotek is also a sample based synthesizer, but it's strength seems to be using multiple LFOs and modulation routing to achieve the movement within the sounds.  The x-y pad in the main page display allows realtime morphing between different sounds, so it is very organic sounding.  It also ships with mostly wave samples of nature sounds, so you have plenty of ambient source material to tweak.
 
But for the same money, I would probably pick Iris 2.  It looks like it would be more productive.  It is also very unique with the spectral filtering, and the workflow is very intuitive and visual.  If using the LFOs and mod matrix is what gets you going, maybe Biotek is for you, but this is what keeps me from digging deeper into Synthmaster.  It can be done, but it takes some work ...

occide
 And it's not always as simple as mashing 4 random samples from your personal library together.

Happy accidents! 

Getting back to very organic sounds or what sounds like them, the granulars are excellent at this. The more organic the original sample is before Granite or Mangle gets to work then the more organic and very complex does the produced pad sound result. Granite and The Mangle do not sound alike and although they are both granulars they do different things resulting in the different sounds.  Granite has enormous modulation options (of parameters) and the means to create the modulations with your own self expression and record and playback those moves accurately. That is a pretty cool thing to watch. 
 
Imagine making sounds with Granite and then importing into Mangle and going further. Or import a Granite or Mangle sound into Iris 2 and manipulate from there.  Increases the possibilities.
 
Making very closeup and quality recordings of things very natural, instruments but also many day to day sounds is rich food for all three synths mentioned here to get to work on.

Just a quick note: I tried the Serum Demo now, so I had a 1:1 comparison with my attempts in Iris 2.
 
My personal opinion in regards to the topic:

• Iris pads sound a notch better than Serum
• Serum got some great FX like Delay and Reverb, but if you listen to the dry signal Serum still put on pants one leg at a time like most other synths
• Even with the custom wavetables option and the point that Serum has become a defacto-standard with loads of free and commercial patches available I think $189 is too much for Serum. It clearly has dated a bit (yeah I know, the Demo is not the most recent version, but I also watched the videos.) For me personally around $120 would be a fair price.

If you want to make ambient like me you can easily go with Iris and couple of samples, you won't miss out on anything in comparison to Serum. Still if you don't care that much about the price Serum will be a great synth for ambient, standalone or side-by-side with Iris 2 (or other synths).

Funny how things go.. this afternoon I've been checking out Synthmaster already, because it supports custom waveforms.
 
I already own SynthmasterCM and now tried the Demo of the real thing, plus watched some videos about SM and SMOne. But honestly none of these I do really like. Seems like the creator had a more technical than creative approach on Synthmaster, at some point realized this by himself and tried to overcome with the creation of SMOne - but wasn't really successful in my eyes. Most videos about SM / SMOne show that, too. E.g. the CMMagazine Video about SMOne barely manages to produce anything but a flat base sound in more than 20 minutes, clueless about what knobs to turn.
Some big names like Armin Van Buren suggest it's a great and powerful tool. If it is, it just takes too much time for a hobbyist like me. 
 
You forgot Tone2 Icarus. But as it almost the same price as Serum, it's pointless again, cause Serum has become a standard. Even if it's as good as Serum it would have to cost significantly less to compensate that. Hard times for being a VSTi Dev I guess.
 
Guess I'm gonna wait for a UVI Falcon sale or get it for next xmas or whatever.

sharke
Worth noting that Serum is available on a rent-to-own basis - $9.99/month until it's paid off. 

Thanks, but in my case that doesn't change anything. It's not that I couldn't pay the amount, it's more that I don't want to pay that much for Serum. I guess most people around here are more serious about making music than I am. It's a hobby, just for fun and relaxation. (Which btw. I think is the best approach for good results anyway).

abacab
 
You have plenty of tools already.  There is no such thing as the "one" synth.  Learn what you have, take it to the limits, then if you feel you need more you will feel better about spending more money.

 
This! I got Synthmaster a while back and at first I was a little put off by the learning curve and it is a slightly unusual layout too.  But once I really started working with it then I found it has a very impressive sound.  A deep complex ambient pad type track a la Eno for example could easily be constructed from nothing but Synthmaster alone.  Especially if you start importing complex oscillator waveforms.   All the elements are right there in front of you. (.....take it to the limits)  You may need several instances of Synthmaster in order to create a complex soundscape like this.
 
I am running an iPad in an Alesis IO Dock as an extra synth and it performs well in that mode.  I have got two Korg synths on there, MS20 and Polysix.   And a third.  Synthmaster for iPad.  I can't believe how fat and powerful Synthmaster actually sounds compared to the other two.  He has designed it for sound.  First and foremost.
 
Synthmaster One is a slightly different beast and some of the sounds are really beautiful.  Good companion to Synthmaster as well.  Sometime in the future I believe Synthmaster will take a major step upward.
 
I bought a great video from Groove 3 on Synthmaster.  After watching that a few times it really changed things for me.  It explains every single parameter.  Some real help like this speeds things up and opens things up big time.
 
It is not only modern synths that can do this.  I have got a flagship EMU Emulator hardware synth that I have picked up some amazing sounds for recently.  Third party patches of deep complex and ambient sounding pads.  The first patch has all the elements in it but the rest of the patches contain just one single element of the total picture.  Which can be transposed over the entire octave range and all manner of editing and sound shaping and effects can be applied to each element alone.  Then you can put it into multitimbral mode and sequence 16 elements of the ambient soundscape at once.  There is no limit to something like this and the possibilities are infinite. 
 

I have been playing around with the free Fracture and Hysteresis from Glitch Machines, with some interesting results just putting some rhythmic material through them. 
 
Starting with a basic dry stereo drum pattern from an entire kit in Addictive Drums.  It can be morphed until it no longer sounds like drums at all, and the rhythmic patterns seem to create some interesting ambient motion.  It might also be fun to break the kit down to individual audio outputs and try processing each piece with a different preset that works differently on each timbre and pitch.
 
Also, the free (until June 8th) Diffuse from Surreal Machines can also add some additional delay and reverb to open up the space a bit more. 

I think the ultimate organic pad machine has just been created. It is called 'Thrill'
 
Check it out here:
 
https://www.youtube.com/watch?v=wP_Jbs0i49Q
 
Now this is what I call serious. Having dynamic and full live performance control is the way to go here.
Try recording all the audio demos and then drop those into Iris 2 or Granite. You will be amazed.
But this does look good. Pricey though. The cost off a full DAW alone. 
 
https://www.native-instruments.com/en/products/komplete/cinematic/thrill/
 
Our cost is $435 AU and I guess if you are fairly serious about using something like this then and even making money from it then it is a good investment.  

abacab
At least Thrill can run in Kontakt 5 Player!

 
Yes and I am glad of that. I think with the other half of many virtual instruments that do need the full version of Kontakt, is a bit of a shame.  A huge outlay just to be able to use some other virtual instruments.  But the Kontakt player does work for many things though.  Make sure you update it to the latest update.
 
But the Thrill concept looks interesting. The whole X/Y pad thing is very cool. I have got an iPad connected to my studio via an Alesis IO Dock and it is easy to setup large X/Y pads or even multiple ones and send that data into the sequencer.  Which is very cool for this type of thing.  
 

Thrill is about as organic as you can get.  It seems to move between very unusual orchestral sounds and electronic textures.  Listening to it though it seems to be very natural and organic most of the time.  Not cheap either.  But very different from any of the synths mentioned here so far.
 
I have produced many very organic sounding ambient textures over the years.  You need to steer away from the more conventional synth type oscillator waveforms because they will always sound like that.  Samplers are good because you can record very real and organic sounds and manipulate them with amazing dexterity.  Granite transforms very natural sounds into amazing organic sounding pads.  In a snap.  The Yamaha SY77 was cool because it was an all FM machine but the sample part of the ROM could be substituted for the oscillators in the DX algorithm.  Thus the sounds changed and became very organic and real sounding.  Nothing has emulated the SY77 yet either which is sort of interesting.  But the Yamaha Montage may be able to do it though. They have put those features back in.
 
Another option might be a synth that does resynthesis.  Something that analyses an organic type sound and re synthesises it to great accuracy. e.g. an additive synth.  Then you go in an edit the synth part further.  Moving it away from that sound again into another direction.  I have got a hardware Kawai K5000 which is an additive beast.  I cannot believe how organic it can sound too for such an electronic instrument.  I have a box connected to it which allows me to tweak 16 of the most important parameters.  Talk about shifting sounds away from one place to another.