Here are specs I have found on the net.
http://reason-expert.com/articles/explo ... 142-mixer/24 dB of boost or attenuation at 12 kHz and 80 Hz
The Spec is the same for Compatible and Improved EQ settings. From what I remember this was a bug fix.
Source: ManualWith Reason 2.5, the EQ modules in the Mixer were improved to get an even better sound and character. However, if you want to play back songs made in previous Reason versions, you may want to use the “old” EQ mode to ensure that the songs sound exactly the same. On the back of the Mixer 14:2 you will find a switch for this - select “Improved EQ” for the new EQ types or “Compatible EQ” for the old-style EQ. The parameters are exactly the same in both cases.
As far as I can see there is only one 24db EQ available as a RE and that's the Uhbik Q. The Uhbik sounds much better but it can't match the 14:2 EQ as the slope differs.