Should I be able to hear a 4Hz difference in my speakers?

Also this is a good time to sharpen your tools and ears - get some test tones - Vandertones is a free download off the Vandersteen website 11 bands of warbletones below 120 HZ, get SPL meter and or some iPad based tools ( studio six digital for example ) or REW running on laptop.... improve, learn, fix setup, work on the room, etc...

@tomic601 , great advice 👍😁

Both have small woofers so the bass around 30hz is mostly coming from the ports.  In my experience, larger woofers are capable of higher quality bass at lower frequencies than smaller woofers.  The larger woofers will probably go lower before the bulk of the output transitions to the lower quality bass coming from the port.

Hi traceyc.  If the recording engineer didn't give it to you, you won't hear anything. Only organs (pipe) are going to give you much down that low. One octave below 32 Hz would be 16 Hz; so musically a 28 Hz note would be in the "La - Ti" range on the scale downhill from the 32 Hz note (being the "Do" - of the do-re-mi-so-la-ti-do scale). A subwoofer will help. They are easy to build and the boxes are simple. Check out the DIY sites.

To be able to hear the difference, at the very least, the music being played should contain those low frequencies.  It's pretty safe to say that most (not all) music doesn't go much lower than about 40 Hz.  In a hearing test, I found that I start "hearing" bass at around 36 Hz.  Empirical evidence supports it: I feel no lack of bass on tower speakers that go to 30 Hz and even 35 Hz, but I did sense the bass was lacking on towers that go down to 38 Hz, and wound up buying a sub for them that goes to 31 Hz - and it made a world of a difference.  So, to answer for your specific situation, between 28 Hz and 32 Hz, if you're like me - you probably won't hear it.  But if the 4 Hz in question were between 36 Hz and 40 Hz, or 40 and 44 - you'd probably hear it.