My sound card is a Soundblaster ZX and the drivers provide an EQ section. These changes are applied globally to all sound. Like most EQ I can't give it a detailed curve but it is at least a place to start with modifying the sound.
Inner fidelity provides the following human response target curve which is research in progress trying to build a better target curve.to make headphones sound like a pair of decent speakers in a room. The black line is the ideal curve for headphones whereas the green line is for speakers to make sound flat.
Given the target we need to know what the raw response of our headphones are. Thankfully my Sennheiser HD 598s have been reviewed by Inner Fidelity and they have the following curves. The grey curves are what we want as they are the raw data and not the adjusted curve.
Give all this information what can we do to improve the sound from the headphones to make them sound more natural? We can take the target response curve and the raw curve of the headphones and work out what the EQ is to drive the headphones closer to the Human target response curve.
We start by capturing the volumes in dB at the EQ points of the Human target response curve for headphones. For example at 31 at the value is +4dB, at 16k its -10dB. Then we do the same thing for the average grey line of the HD 598', so at 31 its -33dB, at 16k its -40dB. The problem with the headphone values is they are much quieter, and in this case the middle point is -30dB, so we need to add 30dB to zero the curve out.
We now have two curves, one being what the headphones actually produce and the other what the target is, all of which compensate for sound recorded on a microphone and the average human body response. To work out what the EQ changes necessary to bias our headphones to the HTR we need to take the HTR value and take away the headphones value. For example at 31hz its +4dB for the HTR and -3 measured for the headphones so it ends up +7dB. Do this for all the frequencies and you get a set of frequency changes.
|EQ Frequency||HD 598 Raw||HD 598 + 30dB||HTR Target||EQ Change|
So how does it sound? It sounds great. Its amazing what these change can do to improve the sound of a pair of the HD598s. It doesn't sound like a set of speakers in the room but its a lot closer than the flat EQ at achieving that. What is most interesting is this has improved positioning information for SBX pro in games and that is worth the effort. So while you can't use my settings you can generate your own with your headphones raw curve.