Hello,
 
If you are using Platinum or equivalent, Each of these plugin's have "Chamber" settings. Blue Verb from Nomad, Perfect Spaces older, Sonar Breverb and Solo Rematrix. This may narrow down a place to start reviewing straight from the program. IHTH..

I know that the OP was asking about SONAR but....
 
Sinatra did quite a few recordings in the United studios in California.... which I think was converted over the years as Ocean Way Studios (Bill Putnam's old studio).  Anyway, UAD has a plugin called OCEAN WAY STUDIOS which is a multi sampled IR effect done in different Ocean Way rooms with all types of vintage mics. Frank always sung with the band LIVE as you probably know so this approach has some logic to it.
 
If I was going for that Sinatra sounds for vocals, I would probably try this one first with a 47 or 67 mic (you get both the sound of the room with different mics).
 
Obviously, you can use UAD plugins in SONAR.
 
Jim

Thanks for drawing my attention to this.
 
I went back and listened to some Sinatra and found All or Nothing at All (from Sinatra and Strings, 1961/1962, be careful he recorded it many times).
 
There is a buildup of strings at the beginning and then they stop, revealing the deep reverb from the session. Worth listening to just to hear the reverb.
 
My feeling is they (the whole production team) really learned how to work with what they had. The arrangement, the musicians, the room, the equipment, etc.   The equipment was simple but the usage was maximized.
 
 

I found ReMatrix Solo and gave it a try and WOW, there is a pre-set called "Vintage" that is pretty close - lots of immediate mid-rangy reverb! I'll keep fooling around with it but it's pretty nice as-is. It took me a while to find ReMatrix as SONAR likes to give you more choices than you'll ever need.
 
Thanx to all for the help and especially to TheMaartian for the Solo tip.

jepp, a convolution reverb is the ansver. ReMatrix does this pretty well by using the charcter of a real room. I don't remember exactly how it works but I think you send out a sound in the room and record what's bounce back (pink noise I think), ReMatrix can then use this information to modulate any signal you feed it. Pretty amazing if you ask me :)

Glad you found something that works!  I totally forgot about ReMatrix to be honest. I saw you used H-Reverb so thought you might have a larger Waves collection with IR-L/1.

Actually, I own the Waves IR-L/1 and the whole "Gold" suite but never even tried it before. I usually used "RVerb" which works well for most things as well as my Izotope 2. I think I can hold on to my $300 as the built-in FX seem about as nice as H-Reverb.

Ah well many people don't realize IR-L comes with multiple GBs of impulses that you need to download separately. The default menu is like 6 general items. If you haven't installed them, definitely do, they're super useful. 

Of course if you need the ultimate in IR engines (I know this is subjective), ALTIVERB 7 is pretty hard to beat.  The IR library is second to none, with all kinda of real spaces sampled and are included (as are all the new IRs they release).  But, it may be overkill and it isn't cheap but I think it is amazing. Even has a graphic mode to place the source closer or further from the recording mic.  This product is also highly used in cinematic productions to simulate real space for foley artists.
 
Just added some info,
Jim

I lust for Altiverb, I've worked with it in a few studios. But yeah, it's expensive. And I honestly haven't had a situation that I really really couldn't do with something else.