I have decided to start practicing after 15 years! Both of my daughters are now playing so I passed down my beginner and intermediate flute and bought a new one for me. I bought a Pearl quantz coda. I have only had it about a month and love the sound. However, I noticed when I play middle D and Eb there is an odd buzzing sound. My daughter tried and got the same sound. I almost think something is vibrating?? I don't hear it in other registers. I have had some trouble with the low registers, but I think that may just be me! Any suggestions?? Thanks.

be sure that all the little screws at the ends of the rods are screwed in tightly, or just take it to a good technician for a good once-over

Patrick's right about the tech. A good going over by a competent tech should solve the vibration pretty easily. It may also make the low register easier, as this range in particular requires that the flute be in top condition, with no leaks anywhere. Chances are after 15 years you also just need to build your embouchure back up. Visualize blowing down more into the flute for the low range, and start working exercises in that octave, and I'm sure it'll start to come back.