I have compared just about every VST host I can get my hands on. (Those with free demos available.) They include:
Spin Audio VMC
I have 3 main criteria that I am looking for:
1) Low Midi Latency
2) Ability to Sync to Midi Clock
3) User interface
I am using a PowerMac G5 with ProTools as my DAW/sequencer and running the VSTi on a separate PC (P4 3.2 G, 2GB Ram). On the PC I am using a WaveCenterPCI card and going out ADAT Optical to ProTools. I was using MIDI through the PCI card but switched to MIDIoverLan CP. The latency times were slightly better with it so I am sticking with it. Also MIDIoverLan allows for very flexible routing and I am no longer limited to 2 MIDI ports from the Mac to the PC.
My test was pretty simple. Set up a track in ProTools with 4 quantized quarter notes and played them back with EWQLSO Harp, NI FM7 E-Piano, and Stylus RMX. The ASIO buffer was set to 256. Surprisingly each of these softsynths had latencies within 1-2 ms of each other.
Forte, VMC, and RT Player had the worst latency. In my tests their numbers were all between 18-21ms. Not terrible, but if you are a keyboard player this is pretty noticeable while playing. Especially fast passages.
The others were all better. Their times all fell between 8-12ms.
As a reference point I tested my Roland XV-5080. It's latency was consistantly about 2-3 ms.
Ability to sync to clock :
Forte, VMC, and Bidule can all sync to external clock. But they can't handle abrupt tempo changes. They all swoop down or up to the new tempo. Bidule was the slowest in changing while Forte and VMC seemed about the same. This is important if you are holding a rhythmic loop or arpeggiated synth over the tempo change. Unfortunately, for me the only way to do this consistently is to use a plug-in within ProTools. Otherwise it's sloppy.
The others don't sync. Or if they do I couldn't figure out how. It's surprising that FL studio doesn't sync to external MIDI clock. Maybe I just missed it.
Forte has the easiest, simplest, interface hands down. It is basically a virtual rack. I don't know why there aren't more options like this out there. Unfortunately, I couldn't try out V-Stack because there is no demo. Chainer is also pretty simple. But not as nice as forte. FL Studio has a very nice interface but is a slightly different beast. It's not simply a VST host. It is more like Reason. It does some cool stuff. And probably with the right template could be pretty easy to use. Spin Audio VMC is pretty decent, but seems more complicated than it needs to be. Also it was less stable on my PC. And it had a problem syncing to external word clock. Bidule and EnergyXT are interesting but a bit complicated and not simply virtual racks. They are more like modular synths. But again perhaps with the proper template it would be ok.
I really wish Forte had better (lower) MIDI latency. I will probably end up using Forte and then compensating the Midi Tracks in ProTools using the MIDI track offsets feature. Since the latencies are pretty consistent this should work well. It's also too bad that the External Tempo Sync isn't a bit tighter. But it doesn't seem like there is any host out there that does a better job, so maybe it's the nature of the MIDI clock beast.
It's too bad that FL Studio doesn't sync to MIDI clock. If I missed it and somebody knows how to do this, chime in. With the right template, this could be a very cool application to use. Bidule also could be cool. It does have tempo sync and good latency times, so I may fool around with it more and see if I can get used to it.
I'm really surprised that a company like Native Instruments doesn't come out with a VSTi host. I would imagine if a company like that came forward and made a good looking, easy to use, VSTi host with a Rack-like interface they could sell a ton of copies.
I'm pretty sure FL can sync to an external clock source.. I'll check it out when I get home (don't have my music computer on hand). I would never choose any application over FL5 right now though - I routinely use dozens upon dozens of VSTs, both instruments and effects, and rarely have any problems.
I gets even more complicated when you throw diff. sequencers into the mix. For instance, Ive found that V-stack (actually the simplest ,easiest , best interface for me..) has really great tight latency with SX , but terrible latency with Samplitude.
Forte is tight with Samplitude but since Sam doesnt have the midi tempo track that SX has, has worse tempo syncing problems.
I find myself Clicking windows open and resizing alot with Forte..but overall its the best and has more features and is actually being updated and has great customer support. Something I`m valuing more and more..
Who knows what will become of V-stack , no one knows, requests are never met..Its basically a black-hole-crap-shoot. Rich
I bit the bullet and bought V-Stack. I figured it was only $50. As suspected it has very good latency numbers. But they fluctuate more than the others. Any where between 7ms to 12 ms with 256 buffer setting. It really is the best interface of all the hosts. Now if only they would add Midi Clock sync and fix the 8 hour bug! I figure I can continue to run Stylus and and other tempo dependent plugs on my Mac. It's more solid that way anyway. My PC is primarily for EWQLSO anyway so sync isn't that big of a deal.
I hope Yamaha continues to support and hopefully improves this product.
I don't officially KNOW what the 8 hour bug is, but after about 8 hours or so in my studio, VSTACK STOPS WORKING. I've seen posts saying simply hit VSTACK'S "PLAY" button. Sometimes that works to kick it back into gear. Often (MOST often in my case) it doesn't: I have to restart.
Bummed I can't get multiple instances of VSTack on a PC. Anyone know how??? (One instance is not enough, I definitely need more than 16 channels).