Certain Sony NW-A300 Walkman users experiencing 10dB drop in Low End (Update)

This issue was first mentioned by emilsoft on Head-Fi, (please correct me if I am wrong) a few days ago. They reported that their NW-A306 Walkman in DAC mode is experiencing a 10dB drop in the low end frequencies. I will quote what they said directly:

Update:

So it looks like Sony is aware of the problem and has confirmed it is a software issue. Sony is planning on releasing a firmware update to fix it. See head-fi post here. Thanks Richard.

This is what I see. I can't mince words about this - it's not even bright, it's just plain wrong, we are missing about 10db starting from 250hz all the way down to 20hz. I will show this to Sony and they'd better take it back as they sold me something which doesn't meet basic audio playback specs.

Here is the NW-A306 frequency graph from the post:

Sony NW-A306

Emilsoft also posted the same frequency graph for the NW-WM1AM2 and there is no drop in the low end frequencies like in the new A-Series.

NW-WM1AM2

The user does not think this is hardware related but a firmware issue, and how Sony has tuned the new A-Series. If this is the case, then perhaps this can be solved with a firmware update.

User dstaley also seems to have this lack of bass in the low end. The issue does appear to be limited to only one region with users reporting even imported Japanese models also being affected, and US models.

If you own a new A-Series and wish to test it, user rlw6534 has created a guide in this post how to check the frequency graph.

A factory reset according to users does not solve the issue.

So it seems the problem is rather random, so far no pattern has appeared. I would highly advise anyone to either cancel any orders or pre-orders as there is no way to tell if your device will have this issue, especially if you ordering internationally and importing it to bypass the volume/output caps.

For any users in Japan, please test your models to see if this issue also exists in Japan for the domestic market as well.

Thanks Dylan for bringing this to my attention and to Emilsoft for their investigating. 

And if anyone from Sony is reading this, is this an actual issue? Users are reporting they can hear a drop in the low end on their devices. If this can be fixed by firmware, that would great, if it is hardware related, that would be unfortunate., especially for users who have imported their Walkmans.