Considering used towers under $1000..

towertone,

That is a good news. I have no idea where it starts feeling like a deep (and strong) bass so input from others is valuable. On the other hand, and for whatever it is worth, Monitor Audio Silver 6 I suggested are claimed to go to 35 Hz but they simply do not feel like having a major bass in the room I have listened to them in and associated equipment (Yamaha 501? 701?). Maybe they do, it just is not a major "oomph" some people crave. It is good enough for me, though and I feel they sound really good overall.

Another "by the way":

It is unlikely that any of the speakers in the range you are looking for ($1000 used, probably at most $2000 new) will give you really deep bass. Others may add to that thought if having more experience as there are many speakers I have never heard (of).

I think audioman58's recommendation may be what you need, if bass is of importance.

NOTE:

GERSHMAN Sonogram, not Gershwin. In case you search for them. Great recommendation, too.

https://www.audiogon.com/listings/lis97h27-gershman-acoustics-sonogram-great-speakers-cheap-full-ran...


By the way, if you could throw a rug or two somewhere on the floor, it may be worth it.

Monitor Audio Silver can be found in that range. Smallish, but refined.

For example 
https://www.audiogon.com/listings/lis96fjj-monitor-audio-silver-6-loudspeakers-new-in-box-5-yr-warra...
https://www.audiogon.com/listings/lis97heh-monitor-audio-silver-6-floorstanding-loudspeakers-rosenut...