Yeah, I just did some informal test at 20hz tone generator and I couldn't figure out which was better. 900 and 909 seems to have similar deep bass response, and I did notice that my whites were on uneven in the left and right channel. The green ones seemed to have better matched transducers.

I'll have to dig up a test track or make a tone sweep, but I assure you the anniversary tunings reach deeper. This is why the anniversary tuning 909 sapphires, reach deeper than the 909 reds. Still waiting for the next color 909's............

I need to find a good way to measure accurately, the difference is very small if any. It's almost like the white ones have a flatter curvature than my green ones. I'll report back here if I find a good way to measure the difference. Sound wise, I think the green ones are exactly like the red...

just google for purple th900, a bunch of different boutique audio stores are selling them.

OMG these Purple ones are making me lust, but I already have the white and green ones :p Seriously though, my white versions aren't as "thick" (they have a thinner profile from the side) as the green ones. It looks like the purple ones also have the thicker profile like the green or regular red...

The new 900 pearl whites have the same tuning as the 900 sapphire blue -- the only thing different is the color of the cans. -- tuning wise, the white and blues have significantly more treble energy. Many people characterize the tuning as sibilant, but it doesn't bother me. On the bass side...

Hi, I actually sold the X00's a few months ago because they are rather unimpressive. Now I have TH-909, Th-900 green, and Th-900 white. All balanced, NO mods. The deepest reaching model is the 909, but the 900's green (and red) have the most quantity of mid bass. the 900 whites and blue sound...

Drop x Fostex TH-X00

Fostex TH-909

Oh the 909 still has that treble energy. But it's the midrange that comes into focus. The 900 SB/PW, now those have some serious treble.

Yes. I have a green pair, which has the exact same tuning as the reds. The 909's actually reach lower in frequency response. But the 909's are less V-shaped in frequency response.

Hi, new member here. I just got the pearl white fostex 900's in yesterday, and I can confirm that it does not have the "best" fostex bass. So far the best fostex can for sub bass, bass extension and weight is the th909 red.

New Fostex addict checking in!

Long timer lurker, I'm here to finally participate in the discussion. My headphone obsession is Fostex Dynamic headphones, THX AAA amp technology, and super low distortion gear. While measurements can't ever tell the whole story, they can definitely help us in developing high performing gear.