Yes it is only 1 decibel, but at least to my ears (this is of course a subjective thing) the bass boost does not sound "right" and the NX4's sounds more natural. Plus I am not talking about 1 dB difference in say a noisy street, trying to compare an hydraulic hammer vs a diesel engine on a bus, I am talking a 1 dB listening on headphones in a quiet room, using the same headphones and music file. Hearing is very sensitive and adaptive. At the night when in bed I can clearly hear the noise floor of the room, which is pretty low. I am sure that at day in the same room I would not be able to make out all those little noise, less on a busy street. This is of course just my perception and not a factual thing. Maybe it is just the slope in the Topping is more steep as you say.