I have been a headphone fanatic for thirty years and have owned and used a variety of headphones over those years, to include Stax SR-5, Sennheiser HD-424 and HD-580.  The Sony MDRV6 excells as the best value of any headphone that I've ever owned.  They are especially good at producing natural-sounding deep bass, and the overall octave-to-octave balance is excellent.  The sound quality is all in all comparable to other headphones that cost considerably more.The MDRV6 is especially well-suited for travel due to the collapsible design, and for noisy environments or for quiet environments such as a library where the sound emitted by open-back headphones would distract others.The MDRV6 is not quite as comfortable as some other headphones, but the comfort can be improved enormously by replacing the pads with the velour pads from BeyerDynamic.  The pads that come on the MDRV6 have a non-breathable cover, and significant additional discomfort is caused by the way that the thin foam cover is glued to the pad around the inner circumference of the pad, which prevents the top and back of your ear from slipping into the space between the pad and the face of the headphone.  This forces the pad to rest on the back of the ear, which compresses the ear and eventually becomes uncomfortable.  I read on a web forum where several people had replaced the pads (which eventually come apart) with a velour pad made by BeyerDynamic, and after I did this replacement on my one pair that had a damaged pad, the increase in comfort was so great that I immediately did the other pair.  The thin cover can be glued down to the headphone face if needed to hold it in place, which then allows the top and rear of your ear to naturally  slide under the inner circumference of the pad, which is considerably more comfortable.  I can recommend this trivial modification without reservation to anyone who owns these headphones.  Even if you don't replace the pads with the BeyerDynamic velour pads, I suggest removing the pads anyway, then carefully separating the thin cover from the pad, and glueing the cover directly to the headphone surface. 

Question: What is the tonal balance of these headphones?
Answer: I have been a headphone fanatic for thirty years