I have written a small blog post on how to use Sennheiser MX500 with Rio Karma for best sound quality. It makes use of parametric equalizer and frequency response curves. This is not my original work. I have just gathered some information from various sources and compiled it in this post.
Not sure if this is too basic for this forum. Thanks!!

Is it not best to listen to your music with no equaliser? I know some people like more bass for example (get better headphones maybe?), but I think that imparting as little influence on the sound as possible should result in what the sound is meant to be like, i.e. closest to it's original recorded form.
Each to their own though.

The equalizer should not be used if you have really really good headphones (flat response at all frequencies). Here, by using equalizer, we are trying to compensate for the flaws in the normal headphones.

But I think that was exactly his idea, to compensate for the improper frequency response of the headphones, so the music sounds as it was originally intended to.

Edit: damn, you were faster

o ic

I highly doubt that you are achieving optimal corrections using the headphone.com graphs. These graphs are made on a dummy head, and FR anomolies(especially into upper midrange and treble) can be an artifact not inherant to the transducer(s), but possibly due to reflective interference(s) and/or resonance(s). Also, direct measurements such as this do not reflect the tonal balance as would be percieved from a loudspeaker system, due to not accouting for the HRTF(head related transfer function), so this is another factor that must be considered. Now, concerning actual transducer/rear enclosure behaviour: in order to isolate driver behavior vs. on-the-head behaviour, an analysis/measurement should be performed using a non-interference measurement system. Ideally, the two response plots should be compared in order to realize what is actually occuring. A relevant analogy: the dummy head measurement is the equivalent of a total-room speaker measurement. A non-interference headphone measurement is the equivalent of an anechoic speaker measurement.(While speakers have to be analyzed at several axises, this is irrelevant to headphones, and remember, this is only an analogy.).

-Chris

Hi Chris, I do not understand all the technical terms that you are using so I cannot comment on them. My point is that the headphone response curve need not be very accurate. Even if the curve given by headphone.com is not accurate, it's not very far off. And that should be enough for our purpose. If it still does not sound right, we can always correct it based on subjective tests.

No headphone will be absolutely perfect. There for some careful/precision electronic correction can always be useful. Additionally, the seal of the headphone pads with the ears will affect the low frequency response. A headphone will seal a little bit differently on each individual.

As far as wanting to listen to "closest to it's original recorded form". No thanks -- this is only something I like to do for reference, not musical enjoyment. Considering the typical recording is not great(and not linear in the first place) -- I imagine that it is rare that a completely nuetral response is desirable.

-Chris

I'm sorry if I was not clear. Please quote the statements that were not clear and I will explain them in depth.

Note: it is an error to attempt to make the headphone amplitude vs. frequency response measure as flat. In application, any sound you hear in a real environment(and from speakers), the upper midrange and treble frequencies are filtered via(HRTF) your head size and ear shape, considering angle of sound source(s). To achieve a perceived flat response on a headphone, response should curve down as frequency rises, in order to compensate(simulate the filtering of the head/angle) for the headphone directly feeding your ear.

-Chris

I often heard turing the EQ on can dramatically reduce battery life (same with using the back light as well). Is this true of the Karma, and if so how much effect does it have exactly? Just curious is all.

I also wonder if, even with the EQ off, and good headphones that give a flat response, the Karma is even capable of outputing a truly flat response. Surely variables, such as construction, software, and the compression used have some effect as to how flat music will play back.

Hi Chris, Can you please explain this sentence in a little more detail? I would really like to learn more about these things. Thanks!!

Well from my understanding, let's say you have a pair of speakers that have a flat frequency response across the entire spectrum of human hearing (yeah right). When listening to these speakers, they will sound different to everyone because the shape of your head and the size of your ears affects the sounds you hear. If you want to simulate a speaker like sound with your headphones you shouldn't just amplify the weaker parts of the frequency graph, you would need detailed knowledge of how your head/ears react to sound.

Especially with an in-ear headphone. You are bypassing your ears and going straight to your "hearing". What you will probably end up with by amplifying the weak parts of the headphone frequency response is an overly "bright" sound. In other words, the treble is going to be higher than normal.

I think that is what he was saying, but I could be wrong. I personally never bother with an eq unless the source sounds really bad. Hope that helps and I'm not spreading FUD.

Your choice; fair enough. As I said above, each to their own.

And I know I didn't get it quite right with my response to the info that bansal98 directed us to, but I still think that adding no equaliser "additives" is a good thing as long as the headphones fit well / produce great sound etc etc (but maybe this can never happen?... in which case listening to any sort of music will never be "perfect" cos there's so many different factors, with the individuals own hearing ability being the biggest factor... ... maybe I'm just a rambling )


What do you mean "Considering the typical recording is not great"? The actual studio recording or the resulting lossy file for example (if your listening on a DAP [without lossless playing ability])?

As I tried to explain in the last reply: the headphone bypasses the filtering caused by the head and ears on upper midrange and treble, such as when listening to speakers or any external sound source. Becuase of this, targeting a flat response on the headphone will result in percieved elevated response of upper miderange and treble.

-Chris

While it is true that everyone may have variation in hearing, the actual response filtering caused by the head/ears is very similar among people. The main item to be affected is the perception of space/soundstage, among the variation(s), due to the specific head size(s)[relating to cross channel delay(s) and filtering of frequency response], ear shape(s) and sizes. Hearing perception[so far as spatial perception] is very sensative to small differences in high frequency response and delay(s). As for frequency response balance(tonality), this has very small [1]variation from person to person, comparatively speaking. As far as absolute perception; a speaker[or other object in real space] will have the unique HRTF of each person that listens to such source, automaticly applied, since your head and ears get to do their jobs. Back to the subject of tonality: while each person may end up having different sensativity curve[hearing ability], this does not negate a nuetral speaker from sounding nuetral, or a nuetral headphone from sounding nuetral. The personal hearing applies it's sensativity curve to every sound(original or reproduced).

-Chris

Footnote
[1]
On the Standardization of the Frequency Response of High-Quality Studio Headphones
Theile, Gunther
JAES, Vol. 34, No. 12, December, 1986, Pages 956-969

Since virtually every headphone(for example) already has response difference(s) that deviate from nuetral by somd degree, I don't see how using an equalizer is a negative thing. You can use the E.Q. to optimize nuetrality or to adjust to preference. So far as I am concerned, the only bad E.Q. is an E.Q. that is not precise(most) and/or adds noise or distortions within audible levels.



I mean that --- (1) Most microphones used in recording studios do not have a flat frequency response (2) Most recordings are made at distances not represenative of a realistic environment[vocalist being close-miced, etc.), and (3) most recordings are equalized in the mixing stage and further in the mastering stage. To end up with a recording that is tonally nuetral compared to the original acoustic source(s) is not probable.

-Chris

Thanks Chris. I get it now. I'll make the response roll off at high frequencies and see how it changes the sound. I had not considered the difference between listening to speakers and listening to headphones.

I have written a new blog post on simulating speakers on the headphones, after reading about HRTFs etc here. Will be uploading it soon.

is there any way of easily finding a response curve graph? i would like to see how my Sony MDR-CD380 cans stack up against others, and make adjustments to the sound.

The only place that I know of is headphone.com. If it's not available there, you might want to check with your headphone manufacturer.