Originally Posted by alphaman
It's important to note that while metrics (objective data/graphs) may, indeed, improve as a result of various mod(s), the actual subjective sound may not correlate to those changed metrics. E.g., flattening of the freq. response may not appeal to all ears (as the ever-controversial diffuse field vs. free field results indicate).
One particular subjective (controversial) quality is PRAT. I find that even 'phones that display a clean/impressive impulse response may not, in fact, sound as snappy/punchy one that graphically looks (measures) worse. Another unquantifiable is long-term listening -- this may yield subjective results (e.g. listening fatigue) that immediate sonics (or metrics) just can't correlate to. In this case, it's not that objective science is wrong ... rather, it's that currently known-to-human science is missing something ... and may be discovered/quantified by some future da Vinci or Galileo.
Unfortunately, for logical-fallacy reasons -- like sunk-cost fallacy, etc. -- various mod projects (audio forums are full of them!) gain a sort of "pop inertia" ... like some quaint pop celebrity ... and that may very well be the case with THIS thread. Indeed, as I noted a few posts back ... that AKG was probably aware of the port vs. no-port sonic issue .... and they SELECTED to cover it up after important/informed/well-founded decision metrics.
Hence, with proposed mod projects , I almost always (now) either ignore or treat them with extreme skepticism ... a lesson that was learned the hard way
I agree with you, alphaman.
Graphs do not necessarily correlate with perceived sound quality. Psychoacoustics is a complicated phenomenon. Many variables come into play: hearing acuity, personal preferences, various forms of bias (positive and negative expectation), placebo, file type, audio gear chain, etc.
Graphs cannot tell us if the headphone will sound good or bad but can provide a peak into the effects of various modifications, if used properly.
My graphs (and anyone's graphs) cannot be directly compared to anyone else's graphs. Instead, they must be used relative to the other graphs generated using the same hardware:software system, set-up, and methods by the same individual. Measuring All Stock AKG Q701 serves as the baseline, or reference, against which all other measurements are compared. Each modification can be measured and compared to the baseline to better understand the effects of each particular modification as well as combinations of modifications...or a mod configuration.
Measurement graphs should be considered and used as nothing more than tools to improve our understanding of the potential performance and sound quality of various headphones and the modifications we implement. Measurements are easily misunderstood and often misused to "prove" that headphone A sounds better than headphone B... or that modification X sounds better than modification Y.
The mod configs I've tried, so far, and like the best don't have the "prettiest" graphs. The graphs, however, provide clues about what's going on with the multivariate interactions of all the acoustic and mechanical variables involved.
Boosting Q701's bass via modifications results in improved sound quality without messing with the mids and treble too much, IMO/IME. Each person must draw their own conclusions.
Originally Posted by Dafo
I am not sure if I misunderstand you. About the b&w nautilus I was thinking about the long tubes that is also a chamber behind the drivers. Try and google "b&w nautilus" and you will see what I mean.
I think this kind of "snailhouse chamber" could be an interesting headphone design. It is all patented by b&w I am sure and therefore all creativity and development stops right there of course.
Bowers & Wilkens 803S Flared Bass Port
Each speaker comes with an open cell foam cylinder that can be inserted into the bass port to tone down the bass, much like the adhesive disk over the Q701 bass port.
I am referring to the hole centered over the back of the driver that's covered by the stock adhesive disk that, when once removed, fully opens the "bass port." Here's a picture of the lower bass driver and bass port of one of my B&W 803S speakers. Note the bass port is flared. The bass port on Q701 is similarly flared. I don't know, however, if the Q701 bass port functions in the same way as in the 803S.