<< See, this is the problem with using high-level tools, be it Sonic Foundry, or MS Visual Studio, or whatever else. You have no idea how the tools really work. You click on buttons and they do stuff but you have no idea what's going on behind the scenes. >>
It can be done in a multi-step fashion but using MP plugins saves a lot of time when working with large files. Unnecessary additional steps result in wasted time because of writing undo data.
<< The so-called "one filter" is actually performing two separate mathematical calculations. The first calculation is expanding the sound wave to occupy a larger amount of time than it originally did. This, of course, lowers the pitch as a side effect. Subsequently, the program calculates how much the original transformation lowered the pitch, and it increases the pitch of the resulting sound wave accordingly, resulting in what you call a "Time Stretch" transformation. >>
Like I explained above one can just shift the pitch. One can also preserve duration. If you do both the end result is the same. The nice thing with direct X plugins is you can audition the effect in real time and change as you wish. When the desired effect sounds good, you process the data.
<< The metallic texture of the sound must have been introduced due to encoding by a low-qiality click-and-drool mp3 encoder, such as Xing or Sonic Foundry. Such horrible sound artifacts would not have been introduced by a quality encoder such as Fraunhofer or LAME. >>
The metallic sound is a laryn artifact caused by calculated fill in. The results are always encoded with LAME. The artifacts are the end result of stretching something over 350% and interpolating the results. The other choice is excessive reverberation, which in this extreme example has too much stuttering.
Cheers!