When I deal with orchestral situations, once the voice tweak is done, I do not use specialized LF discs to finish below 125 Hz, as I go easy with subs (or avoid them altogether) when doing classical.
I prefer to use full-range systems with a gradual roll-off around 70 Hz or so for this kind of work, as too much boom-boom can sound phony and hyped in these situations.
Add in all the headaches with wind (I usually do this stuff outdoors) and stage noise, and you come to the conclusion that a little bit of sub goes a long way in orchestral.
Before someone emails me about the LF content of the contra bassoon, concert bass drum, tuba, bass trombone, tympani, etc., I said a “gradual roll-off at 70 Hz” – the low stuff will be there, but it won’t be in your face, which is the way it should be for that form.
To finalize the orchestral tweak, I just play a little Heifetz with the Chicago Symphony (Tchaikovsky Violin Concerto). There’s enough stuff there with the brass and the celli to verify the presence of the natural LF I need, and the bonus is his fiddle tone and the hall ambience, as a means to confirm the orchestral relevance of the voice tweak.
Many people use the Michael Jackson cut “Billie Jean” to sort the low end in their FOH systems. Even more use Steely Dan’s “Aja.” I’ve tried both, and neither has the bandwidth or detail I need for an LF tweak disc.
How do I know? That Steely Dan cut can make any old sound system sound OK, which is why it is used by so many loudspeaker manufacturers for client presentations. The Jackson cut has a lot of snap in the LF – also useful for generating good feelings about the performance of a sound system. Reference discs reveal system performance.
If your rig is confirmed by a real reference disc, then the LF from a wide spectrum of material will generate those good feelings, not just ‘Aja” or “Billie Jean.”
Everyone tends to play material that confirms rather than reveals the system. Audiophiles are the worst – those with small loudspeakers tend not to play hard rock, hip-hop or Mahler, preferring to listen to acoustic music, voice, and small group jazz.