Hi all,
 
I have a singer that is going to be tracking over the existing music tracks. I would like to feed her some reverb for the process. I don't want to use a VST and echo because of latency concerns. I wouldn't mind investing in a cheap outboard reverb unit just for monitoring if I could sort out the routing. I'm using a Mackie 1200f, which has headphone outs as well as real-time monitoring. So, I can send Sonar out through the headphones as well as her own voice, but then I have no way to apply reverb. I could send out sonar to a separate out on the Mackie (say 5/6) and her voice out another (say 7), run her through reverb and then feed them both to an external mix and then to a hardware amp. This seems overkill.
 
I would love any ideas on this, and recommendations of a cheap rack mount reverb to use solely for tracking...

Describe your input chain - how is the mic signal getting into Sonar?

According to Musician's Friend, the 1200F has a pair of  balanced insert points. I'd hang a medium quality Verb or multi FX off one, and an EQ/comp chain off the other, OR...
 
If your DSP monitoring software supports enough sends, I route each of the two loops described above out thru their own outs and back in their own input channels. This gives you a lot of flexibility, as then you can set wet/dry ratios if need be, for fine tuning, and both record and monitor totally dry, totally wet, a mix, or all three at once.

Here you go, I just tried it and it worked great.
 
Take your Vox path straight and dry?
 
Then take another vox path? (Faux Vox) and use the same input channel on your sound card, insert your verb on the Faux channel, make it as wet as needed, and select the "Input echo" button on this Faux channel? Set both to record. Then record, both will record, the LV will be dry, however they will hear the wet from the Faux channel because it is set to Input echo, however the LV recording will be dry. (Oh, and you want to use a VST...) There are low latency verbs out there, and regardless, if they are existing tracks? Why would latency matter? Just crank it up, it's a vocal track? You don't have any MIDI to worry about. If it's an existing track with lots of FX and MIDI and soft synths, and what not? Then just export it, inport it to a track called faux bounce, kill all FX in the project, and mute everything but the two vox tracks described above, and the bounce. You shouldn't have to worry about latency, and this gives you the ability to go back and add whatever verb you would like on the newly recorded vox track.
 
It's easy, it doesn't mess with your project, it gives you the verb you want on the input w/o latency issues, and it gives you the dry track you need to mix with. Don't make it more complicated than it has to be, there's no reason to use outboard gear for what you're looking for. 
 
**Disclaimer** I'm not against GAS and have had it most of my life, and there are many good ways and many bad ways of getting to the same goal. I only hope that my ways are "one" of the good ways...
 

If you go the hardware route, be sure to get a splitter so you can feed a dry signal to the DAW.  Let her hear the wet signal routed through the verb and a headphone amp.
 
 
I record using headphones and to be honest, I have never noticed if the signal was dry... I guess I'm not a very observant person huh? If it's dry, it hasn't bothered me.... but now, I will pay attention the next time in.

I'd cruise Craigslist for a second-hand reverb unit, like a vintage Picoverb or Nanoverb. They can be had for as little as $20-40, since those old 12-bit reverbs aren't exactly hot sellers anymore. But they sound good enough for the singer's headphone mix. 

Wow, thanks for all the great advice guys! sorry for the delay in responding - I've been down 4 days with a cold - AND doing a complete re-org of my studio. Jay Tee I was really excited when you mentioned the sends and I just looked them up. Unfortunately, they get printed so that's a no go. Unless I can use the send without the return? I'll have to try that - that might be the easiest route.
 
Bit - during my re-org I realized I have a Boss SE-70 that I use solely for the shimmer effect for my guitar. I have now routed that in through my patch bay and I'm sure it's got a decent enough reverb patch to use strictly for monitoring.
 
The Band - I do have a TON of stuff on these tracks so to get decent latenency with a VST I suspect I'd have to bounce down as you said, which is an option. If I can route the Send out without needing a return (not breaking the signal path) that could be a good option. It doesn't seem right intuitively to me though. I also have a Yamaha mixer with a send on it. I'm now thinking I can:
1. Live monitor the singer's channel with zero latency using the 1200f. Route this to Out A
2. Send the full mix to Out C/D (a stereo pair).
3. Run all three signals to the Yamaha mixer.
4. Put the SE-70 on the Effects Send of the mixer.
5. Plug the singer's headphones into the mixer.
 
Logically, this works for me and I'll give it a shot. If you think this won't work or there are gotchas, please let me know...

I do it all in the box, with SONAR's mixer :-) So I can't comment on OTB solutions. And there are multiple good ways and multiple bad ways to approach it? I'm just thinking, if there's a way you can do it, using the tools you have? (yes I would render the tracks and use only the bounced instrument/other vocal track for her) then you're just working with the
 
1. The backing track
2. Her wet (which doesn't get recorded)
3. and Her dry (which does get recorded)
 
Then you can delete the backing track, the wet track never really existed, and now you have her dry, when she "felt it" wet, which I agree helps some singers considerably. If it works, couldn't hurt? If it doesn't, you can go the external route. 

bitflipper
I'd cruise Craigslist for a second-hand reverb unit, like a vintage Picoverb or Nanoverb. They can be had for as little as $20-40, since those old 12-bit reverbs aren't exactly hot sellers anymore. But they sound good enough for the singer's headphone mix. 

This sounds like good advice to me. I have a Lexicon MX300 that I use in my setup (connected to my Focusrite 18i6 via S/PIDF) and I can route stuff through it that never has to go back to the DAW and is heard in zero latency real-time through monitors or headphones connected to the Focusrite. Granted, this is more $ than you're looking to invest I'm sure, but as bitflipper says, there are cheaper units out there that'll do the same thing and would be perfect for your scenario.

smallstonefan
Wow, thanks for all the great advice guys! sorry for the delay in responding - I've been down 4 days with a cold - AND doing a complete re-org of my studio. Jay Tee I was really excited when you mentioned the sends and I just looked them up. Unfortunately, they get printed so that's a no go. Unless I can use the send without the return? I'll have to try that - that might be the easiest route.
 
Bit - during my re-org I realized I have a Boss SE-70 that I use solely for the shimmer effect for my guitar. I have now routed that in through my patch bay and I'm sure it's got a decent enough reverb patch to use strictly for monitoring.
 
The Band - I do have a TON of stuff on these tracks so to get decent latenency with a VST I suspect I'd have to bounce down as you said, which is an option. If I can route the Send out without needing a return (not breaking the signal path) that could be a good option. It doesn't seem right intuitively to me though. I also have a Yamaha mixer with a send on it. I'm now thinking I can:
1. Live monitor the singer's channel with zero latency using the 1200f. Route this to Out A
2. Send the full mix to Out C/D (a stereo pair).
3. Run all three signals to the Yamaha mixer.
4. Put the SE-70 on the Effects Send of the mixer.
5. Plug the singer's headphones into the mixer.
 
Logically, this works for me and I'll give it a shot. If you think this won't work or there are gotchas, please let me know...

That's a variant of my suggestion, it should work well, and yes, the key is bringing the wet signal back into it's own channel input, not the FX return.
 
I have 32 hardwired ins on the system here, but only 18 channel strips in the DSP mixer,  and 6 of those DSP strips are devoted to FX returns. One pair for a comp/EQ loop, in case I have to take the edge off a pumped up performance, and two pairs for 2 different hardware verb's, basically one for the "room" everybody plays in, the other for an individual effect like verb and/or chorus on a guitar part.
 
I specifically do not record the effected signals for the main take, to preserve max options down the road, and opnce I am sure I have the dry signal in the DAW, I go ahead and record the effected signal anyway, why not?
 
The templates I use in recording always have my main busses, Verb, Delay, Drums, Bass, Guitar, Keys, and Vox preset, with sends to Verb buss, which has a plug that closely mimics the hardware verbs, so there's no fuss, or embarrassment over "naked" Vox on playback right from the start.
 
Even so, I still have full flexibility on mixing, as there's always a fully dry track recorded to "start from scratch" with.
 
The DSP mixer on the Profire 2626 is especially nice in this regard, there are 7 stereo sends, in addition to the stereo mains. Send 1 and 2 go to hardware verb 1 and 2, Send 3 goes to EQ and Comp, and 4 thru 7 feed ins on a 4x4 headphone amp.
 
This gives me 4 discrete monitor mixes in the DSP realm, with fully adjustable FX, and which can then be blended or soloed for 4 additional monitor mixes, to a total of 16 sets of headphones with 8 different mixes.
 
The key to achieving this was in lucking out with the 7 sends on the 2626, adding the 4x4 headphone amp for $175, and extensive graphical documentation on my part to avoid hunting for signals during a busy session. Put another way, if you have several DSP sends, a small investment in a monitor mix/amp and good signal flowcharts will open up your monitor system exponentially, and in my opinion, a robust set of monitor options is perhaps The Key to capturing great performances.
 
I'll go out on a limb here, and place this on equal footing with room treatment. Few other areas of effort will improve results more than control over the instant feedback loop achieved by room acoustics, AND monitoring flexibility.