Hello friends!
I've had the Pro 900 for a few months now. I use it with my ipod. I've "TWerked" around endlessly with all kinds of settings, but I love the sound I get from the set-up that is described below.
Initially, I used it straight out the headphone jack of my ipod. This was not a good idea. You do not get high quality and clear sound without amplification. You can power them to high volumes, sure, but the quality of the sound will be less than ideal.
It is easy to hear a substantial difference with an amp! I bought a Fiio E11. It sounds great from the Fiio. BUT you MUST also buy an LOD (Fiio L3 or L9) if you are listening through an Ipod. You must. It makes the sound MUCH better than without it. Use the L9 instead of a male to male connecter.
Recap: Ipod + Fiio L9 + Fiio E11. This is the combo you want for great portable sound!
(As a note, I like the FiiO EQ to be at 1, the gain on L, and the power on H.) The power setting is inside the unit underneath the battery. I wasn't aware of it when I first had the e11!
I also find it ESSENTIAL to use the "bass reducer" EQ found on the ipod. It tames the bass down a little- to acceptable levels. The bass on these headphones is just too much otherwise, and it really "covers" some of the rest of the music. These Pro 900s have a 10 DB bass boost. It's too much. The bass reducer will pull that down a few DBS to balance the sound better. You will STILL have the wonderful (and huge) mid-bass response that makes this headphone a pro 900. But it will fit in the mix much better. Try it! I am listening right now, and it's just the best sound I have ever heard from my 900's
If you use these settings, I think you will be very pleased with the sound. It is much improved. It is beautiful. The bass is in better check, and doesn't drown out details. I strongly recommend you grab an e11, l9, and use the bass reducer EQ. After that, it's a matter of positioning the headphone well. I prefer the way it sounds with my ears positioned towards the top back part of the headphone. It gives a great bass response! Play around with the placement, after you've used the above settings. It does change the balance of the sound in some not so subtle ways. The headphone is still more BRIGHT than I'd prefer, but it's a small gripe.
The sound is pretty massively awesome now. Enjoy, and please leave me your impression if you try this combo. Have a wonderful life.