Yes, the DBX 1231 is excellent and relatively inexpensive. It's built like a tank, far more robust than the typical DBX gear, part of their higher quality "pro" series of devices.
I will likely be accused of heresy for promoting it on a high end audio site.
I use it quite successfully to correct a particular nasty room resonance that seems to be untamable by other means. I tried miniDSP Dirac based devices that auto correct the room and had poor outcomes with the resulting sound being dull and lifeless even when setting a reasonable target response curve. As Don suggests in the previous post, if you are willing to take on a larger technical challenge, some of the miniDSP devices are pretty much fully user programmable to whatever EQ function you might want.
On the other hand, it's pretty easy to use a simple 1/3 octave analog EQ to gently correct the response curve problems small changes at a time doing adjustments individually for each channel. Try to make as little adjustment as possible to achieve desired audible effect. Use REW or similar software and a calibrated measurement microphone at the listening position as a starting point to identify the main trouble points in the response curve.
Often you'll find a null in response which will lead to the temptation to over-corrrect adding 10-15 dB gain at a particular 1/3 octave position. This will usually lead to undesirable and unnatural results and is to be avoided. Avoid trying to correct for bass roll-off in the 20-60 Hz range if this is due to the inherent physical response property of the speaker. Excessive EQ at these frequencies will only increase distortion and potentially damage the driver if too much power is applied at frequencies below the woofer's physical ability to deliver useful output.
Base your ultimate assessment of the EQ settings on listening tests using a few carefully selected very familiar well engineered recordings.