A more practical approach
If you are searching for a temporary solution to, let's say use the backing tracks for improvising over them without being disturbed by vocals or mid-range buzz, there's some little tricks you can do with audio material in a simple sound-editor without the need of sophisticated and expensive tools.
Of course, because of the (in)-fidelity, the result is not usable for production-purposes!!!
A multi-band graphic EQ that filters out all the frequencies in the low-mid and mid range. Provide a curve like ---______------------
An EQ with a bell-characteristic and a steep curve Q-factor to achieve a similar effect as the graphic EQ
Put the same audio track on two tracks of your audio-editor or DAW and put a Lowpass and a Highpass filter on one track to cut the low and high frequencies. What remains is a midrange signal (depending on the settings of your two filters). Now phase invert one of the two audio tracks you've got. This will nullify the mid-range completely...
You can save these settings in your editor of choice and use it as a 'preset' just by assigning a new song to your audio track(s).
All tree methods serve to get rid of the mid range and do in a simple way what more sophisticated tools are doing in a dynamical time and context-sensitive way - but, depending on the material, not always very good. I showed you the hardcore way that will eliminate the stuff for sure, independent of what the source material is.
But you have to keep in mind that both tracks (version 3) have to have the same volume in order to get the midrange 100% silenced. If you're shifting the volume-ratio by changing the volume of either one track you will get back the midrange step by step.
Of course, by cutting the midrange so bluntly you are also killing a lot of instruments that form the chord/harmony portion of the composition. You are essentially left with bass-drum, bass, low-harmonies, HH, Cymbals, high percussions regarding the rhythm-group. And that is what you actually want when you're searching for a play/sing-along track. But anyways you can regulate the effect by changing the cut-off frequency of both of your filters to narrow down the midrange in order not to loose too much.
Hope that that's it what you've been searching for...
EDIT: If you wanna get fancy with method 3 you can also add a third track and phase-reverse one of its channels (L or R) in case your source is stereo. With that - everything that is usually mono like - the 'dry' vocal signal, centered mono effects etc. - will get removed. Only the effect part of each signal which is on both channels like reverberation an the like will remain. Also effects that are using a modulation of the signal's phase like stereo chorus/phlanger/phaser etc. for e.g. pad-sounds. But usually these 'wet' signals are not very loud...
That signal will now fill the hole in the frequency range that you left with method 3 and give you back some of the harmonical context that might be missing after the brick-wall-method 3. But also the 'wet' signal of the things you want to get rid of.
But because of being on its own track you can adjust the volume of your new midrange to your liking.
And of course - the additional track of this extension of method 3 must have the same filters applied to it than the other phase inverted track so that you actually fill the very hole that you dug in the first place. If you didn't do that you would definitely kill all your BD, base and other signals that are typically centered and more or less 'dry'.
But by storing your settings as a preset you have to do this work only once and can apply it later on to any song you like. You may just have to tweak your preset every now and then...