If the volume control is a rotary type (as opposed to one having "up" and "down" buttons) the following photo will probably enable you to determine a reasonable approximation of the difference in volume control settings that would result between the two attenuators. The markings for the volume control in the photo are calibrated in db of attenuation. And although what is shown in the photo is a passive preamp, I believe that the markings shown are reasonably representative of the attenuation vs. position characteristics of rotary volume controls that are used in active designs.
http://www.hifishock.org/galleries/electronics/music-first-audio/preamplifier/passive-magnetic-pream...
So for example if you are presently using the volume control at a setting corresponding to the position marked "40" in the photo, with a 10 db attenuator you would be using it at about the "30" position, and with a 20 db attenuator you would be using it at about the "20" position.
Regards,
-- Al
http://www.hifishock.org/galleries/electronics/music-first-audio/preamplifier/passive-magnetic-pream...
So for example if you are presently using the volume control at a setting corresponding to the position marked "40" in the photo, with a 10 db attenuator you would be using it at about the "30" position, and with a 20 db attenuator you would be using it at about the "20" position.
Regards,
-- Al