Loudness matching

Hi.
In a stereo sistem I am eq-ing each channel separately. I measurement both at 75 dB. I would like to achieve the same loudness in each of the channels. What indicator should I control in REW? Predicted dB? And why is this value so much lower than on the graph?

Need more information. What is the "stereo system"? How is EQ being implemented? Usually speaker level and EQ can be adjusted independently. For example on an AVR, you would simply implement the EQ, then use the SPL meter at listening location to adjust the level of each speaker, most AVRs have noise signal built-in for this function, or use the REW signal generator. For DSP implementations, generally there is a master level adjustment separate from the EQ bands. As far as ensuring the same level of EQ, just use the same target level for each channel.

dB levels shown at the bottom of the chart are the level at your specific cursor location.

Thank you for your reply.
My system: Wiim pro, Minidsp Flex, Cayin integrated tube amp, Spendor A2 speakers. So EQ goes through Flex.
I set the same target level for both channels, but ... even though, when I EQ each channel differently (for example, I may use more cutting or more boosting in one of the channels than the other), that must changle the loudness respectively.

Location of speakers in the room in relation to your listening position will have the biggest impact on volume of each speaker.

Same answer though, use REW signal generator, level of each speaker can be set independently in the miniDSP, or use the volume balance slider in the Wiim Pro config, under audio settings in its app.

Use REW signal generator and SPL meter can give you general loudness of each speaker, or take a step further and use RTA to get full spectrum analysis. All the tools are there in REW.