Greetings Everyone....
My First Post Here, However I am a member over at Agoraquest where we mostly talk Sony......
Judging from your last question, I think you may be confusing EQ, with bass management....
The EQ will either Boost, or Attenuate the frequency that you have selected...along with others above and below the selected freq....just not as much as the value you have entered....
For example if you choose 1Khz @ +5...you have boosted 1Khz +5 Db along with some of the others above and below 1Khz...think of it as a mountain peak at 1Khz, and the surrounding freqs on each side as the sides of the mountains slope...lower the peak....and the surrounding slope will lower also.
When you Attenuate the same centered freq...think of the mountain being upside down with the same slope of affected frequencies...
Now you just need to learn which freqs affect what notes on a scale, or which instruments....
Bass management will Not boost or attenuate frequencies, but instead, it re-directs them to speakers that can handle them...thus the Large/Small setting.
The effect of bass management may indeed seem to boost bass freqs but that is only a result of sending the larger more "bass capable" speakers those freqs.
The bass re-direction settings available can vary greatly from one receiver to another, and it is best to look in your manual to determine what is available to you with your DE925.
This article here on AH can describe it better than I, and is a good read:
http://www.audioholics.com/techtips/setup/loudspeakers/bassmanagementbasics.php
I find that in my system....bass management settings can be more effective than EQ....
Hope some of this helps....and again...Greetings Everyone
Steve~