I should mention that someone who's better at DSP than me probably
knows why it doesn't work at low frequencies. Hopefully they chime in.
:D

For very low frequencies one could also use a shred that sets a random target() to Envelope and feed Envelope a Step set to "1".

Unlike subnoise this will be independent of the srate and the time can be set in musically meaningful terms like beats, assuming some are defined in the piece already.

Hope that helps,

Kas.