attenuation

 I checked the archives on the subject and admittedly not all 7500+ posts but none I read addressed this elementary level question.
From what I gather from reading a few pages worth this may not be a simple yes or no answer is there ever one. 
So my Technic integrated amp 70 watts driving my Canton 9kmonitor (power handling 50/250 watts 87db sensitivity, gets to roughly 30% on the volume knob before approaching clipping per the meter needle on the amp briefly bouncing to 100 watts mark. The amp has a 20 dB attenuator I can and do engage which allows me to use 80 % or more of the volume adjustment knob( that's right I'm new to all of this actually about 1 year in) thus giving me greater flexibility in volume adjustment.
My question does engaging the 20db attenuator have any negative sonic effects on the music. It would seem not but if it does what is negatively impacted? Thank you for your input.