Hello folks, this is my fist post in these forums!

Well, the PortaPro's are currently the best headphones I own (before them I had nothing but throw-away headphones) and I never had the chance to compare them to some really expensive headphones like, e.g. HD600/K701/DT880.

So now any one of you who owns both Koss PPro and some high-end headphones would probably shout "OMG how can you stand that muffled, ugly, whatnot sound for more that 1 second!".
Well, the first thing I did when I got them was to take the response diagram from headroom, flip it and correct it with that 18-band graphic eq of foobar (btw: I have a Creative Audigy2 soundcard).

This made the sound a whole lot better (definitely not like played through a toilet bowl anymore).
Then, I corrected it a tiny bit towards a less set-back, warmer sound. This is already *worlds* better than the original sound (I listen to things like Fiona Apple, Dredg, Air, Once Upon A Time In Mexico OST, ...).

My question is now, is that even close to the sound of a high-end headphone?
If not, what makes the difference for you? Is it bad harmonic distortion? Unbalanced-ness?
If you tell me that it is still something like worlds apart and why, I might be willing to spend some hundred bucks for a headphone + amp... :)

Btw, another thing that I occassionally use is Dolby Headphone (also via foobar) which makes the sound MUCH more bearable. Actually my favourite for many songs is DH in the "live" mode with an eq-setting which compensates both the frequency defects of the Koss and of the live-setting (so it sounds like played over a good surround system).

What do you think of that?

Chris

(ps: Please excuse by english - it's not my first language.)

Regarding your concern that they are considered bad headphones...

If you do a search in the forums for Koss, you'll see that there are over a hundred threads referring to them.

In my opinion (as well as many other forum participants), they are the best budget phones out there.

-brendan

Ok, maybe I exagerrated a bit. Actually, I convinced 8 friends to buy the same headphone.
But at least, we all know that they are a bit too bassy.
And the highs could be more detailed, although this may be a question of personal taste.

Maybe I should rephrase my question:
Given a good mid-range headphone that can basically reproduce any frequency reasonably well and a good equalizer, can one reproduce the sound of a real high-end headphone, or is there more to it?
It is just that I want to know whether I am currently listening to something sub-optimal while thinking that it couldn't get any better. This would be terrible, wouldn't it?

Christian

EQ is rarely a good answer. The PortaPro is a reasonable headphone but will never sound like a Sennheiser or Grado because the differences are more complex than EQ alone can address. It has little to do with cost.

Any decent set of 'phones should sound very good with no EQ, unless your taste runs contrary to that of the music producer. If that is the case, then you will probably find yourself wishing to change the EQ of almost any headphone you buy.

There is no evidence that achieving a flat response via inversion of a published frequency response is "better" per se. Headphones are a distinctly unnatural way of delivering audio to ears, and many manufacturers (notably Grado) tune 'phones to work well without regard to a "flat response". In other words, they shoot for a compromise that works given the other realities of headphones:

1. No body sensation of low frequencies
2. 100% separation of left-right sources
3. Lack of front-back, up-down spatial cues, etc.

Me, I disable all EQ on all my systems. It is simply unnecessary IMHO.

I think the difficulty is finding what digital processing to apply. I have tried inverting the official frequency response graph but it sounded wrong. It's not obvious what you should do with frequencies and phases. But I have heard it is possible to a large extent for headphones to mimic each other with digital processing.

You are right, but as long as the equalizer does not introduce other audible distortions, going slightly into the right direction with the equalizer should be slightly better than before (given your headphones are not already "optimal").
For your points 2 & 3 there may be some solution (namely crossfeed or Dolby Headphone), although this might be more attractive for signal-processing freaks than for hi-fi listeners...


I was at the audio store yesterday and compared the Koss (with equalizer) to a Beyerdynamic DT880 (without eq), with my own music samples. And it was pretty clear that the highs were definitely better resolved by the DT880. But the rest (everything below ~4000 Hz) was very similar with both setups.
Although the Beyerdynamic was lacking a bit deep bass and had pretty intense highs.
Unfortunately, they didn't have any good Sennheiser headphone there (>= HD 580).
So, basically am quite content with the sound I have, for now.

Btw: my favourite foobar2000 equalizer settings for the Koss are:
-2 -7 -9 -8 -7 -5 -3 0 0 0 0 -3 2 0 6 -3 -4 0 (for a balanced, set back sound - close to the theoretical optimum)
-1 -5 -5 -5 -4 -2 -1 0 0 0 0 -3 2 0 6 -2 -4 0 (for a more bassy sound - maybe a bit overdone)

The 7KHz slider should be at +11db, at least according to the headphone.com measurements but this sounds very very bright.
But for Dolby Headphone, lifting the last 4 sliders by one db each seems to be pretty good.
By theoretical optimum I mean the slightly convex curve that you see in most high end headphones.

Christian

Hello folks,
a little update from my side.

Yesterday, I found out that the equalizer which I was using does a very bad thing that makes it more or less unusable for correcting anything besides pop/rock/classic...
The problem is that it does not generate a smooth response curve (like, e.g. a spline) as one would expect but instead a piecewise constant response curve.
This means you would effectively get a sawtooth-like response curve when you try to correct your headphone.

So I wrote a tool that takes 2 response curves and generates a symmetric FIR filter which can transform from the source response curve to the target response curve (i.e. source=your headphone; target=whatever you want).
The good thing is that such a filter does not distort phases and that it can be incredibly precise.
The bad thing is that one cannot trust the headphone.com measurements (e.g. I found out that the Koss response curve is quite distorted (it is closer to that of the SportaPro); and the AKG-K36P's - my other headphone - is also grossly distorted). The filters can be loaded with the foo_convolve plugin.

I think that the whole thing can still be improved, e.g. I don't know if my method of generating the filter is optimal. If anyone is interested in actually testing such a filter, PM me (I currently have no webspace).

Christian

Here is a very nice thread on the subject of headphones and EQ:

http://www.hydrogenaudio.org/forums/index....c=46738&hl=


For EQ purposes, the biggest problem with the portapros is that the midrange and low treble are uneven:

http://graphs.headphone.com/graphCompare.p...pare+Headphones

You're going to have a heck of a time getting them up to a strong hifi level with that uneven midrange and low treble. It's going to be a tricky EQ curve to fix that. I'm sure it can be done, but it wouldn't be simple. Also, you need to shave off some mid-bass, obviously.

A Sony V6, Grado SR60, Senn HD280, or Senn HD555 is sort of rock bottom (in terms of price -- you can do a lot worse for a lot more money) as far as what you can easily take to a strong hi-fi level with EQ, IMHO. EQ is an extremely effective way to take decent headphones to a very strong hifi level, IMHO.

I use a Behringer DEQ2496 digital equalizer for my headphones. It is an astonishing piece of gear for $300 or so. It has very strong parametric and graphic abilities.

Unsolicited recommendation:

I've found Behringer to be a company that gives you high quality equipment at an affordable price.

-brendan