low bass response

Like @ozzy62 posted, you need to quantify what you mean by 'low bass response'. To do that, use a test tone to find out the bass extension you're currently getting and how even that response is. I've used the following audio test from Audiocheck in the past - link. Unfortunately, this test leaves out the vinyl playback chain.

You can try adjust the speaker settings / positioning as well as your listening position (if you can). For example, if the speaker sounds too bright, set the treble control to -0.5 dB or -1 dB. Adjust the bass control to 'Normal' if set to 'Contour' or 'Boundary'. Move the speakers closer to the back wall.

As @wlutke mentioned, try walking around the room while the test tone is playing to identify potential listening positions with the level of bass you're seeking.

If none of these seem to work, then it's time to consider adding a subwoofer or two.

@jw944ts 

You want to measure from your listening position. Bass response will vary from location to location in your room due to room modes.

If you've tried moving the speakers and/or your listening position and you know your gear's frequency response is flat down to 20 Hz, then you should probably consider adding a sub.