The ability to change pitch and time simultaneously while retaining good audio quality is a more recent development, and something you couldn't do with tape.
@SToons
That is precisely what I'm talking about by 'varispeed' being a relatively new thing, and also answers the point of how it can differ from tape.
And yes the ability to play something at 80 bpm to replay at 150 is something to behold, you ought to try it, you play it in exactly the same key and tuning, just like you would with a midi phrase, changing the tempo leaves it unaffected in every other aspect.
You see 'varispeed' is one of those loose terms (similar to gapless audio) that means different things to different people. To some it means pitch shifting, to others time stretching to me it is the ability to alter tempo (speed) while retaining every other aspect as intended (as well as being able to alter pitch if necessary) and in real time. What is being discussed here is pitch shifting, not 'varispeed', pitch shifting has been available in Sonar to some degree or another for many years. It obviously is not something he does regularly as he'd have found one of the countless ways of successfully approaching it already.
The complaint was to do with Sonar not providing pitch shifting capabilities, which it does, rather than providing real-time 'varispeed' which it doesn't.
If you follow the OP to any extent you will have realised this was just a mal-constructed opportunity to knock Sonar yet again IMO. Any benefit of the doubt that I have previously had toward the OP evaporated long ago, again he wasn't interested in the many solutions offered that will work here, the thinly veiled point was to carry forward some idea the Sonar is lacking.
He can do what he is describing here easily as has already been suggest by bouncing down a mix with the pitch slightly altered so that the out of tune hammered dulcimer 'massive' can track to it and then shift the pitch of the resultant track back to fit the main mix. It's purely a pitch shifting job and a trivial one at that.
Better still tune the thing, or if you do a lot of hammered dulcimer get an 'in house' one and do it properly.
Accelerando's and Ritardando's whilst available with midi scores are nigh impossible with audio without varispeed. That would be a better point to make if you wanted to cite Sonar's lack of varispeed. The tuning argument was a lame construct to launch such a transparent campaign the OP consisted of.
Had Mike had asked the simple question of how to track a slightly sharp or flat instrument against concert pitched backing he'd have got many simple answers from people that would have solved his problem and he'd have realised that Sonar is not lacking in this ability. The simplest way of solving this for me would to be to record a midi guide for the guy to track to and knock the tuning of the VSTi used for that to suit the 'out of tune' instrument, then shift the stem into tune once it's been tracked.
He also forgets to mention using a tape based solution wasn't without it's drawbacks either, like the tape shifting from it's azimuth when the speed is changed and the fact you'd either have to play slower or faster to compensate for the speed change to get the right pitch, altering the feel of playing the piece for the musician involved.
But why ask for help when you can pretend to know it all and say the product you chose to use is flawed?