Recently, having received several new headphones (new to me actually) for testing and evaluation and possibly to keep permanently, I was surprised by the wide range of variation in sound between the different headphones.  I found it easy enough to adjust to strong bass -vs- weak bass as long as the bass was not boomy or bloated to a significant degree.  I also found it easy to adjust to differences in treble strength as long as there were no major annoyances such as strong sibilants and harsh tones.

Once I eliminated the non-contenders for whatever reasons, I was left with my own personal stable of headphones: Sennheiser HD-800, PX-100-II, PX-200-II; Beyerdynamic DT-48E, DT-1350, DTX-300p; and the B&W P5 (my second set, acquired today).  For me, the most intriguing of the new acquisitions was the Beyer DT-1350, which some people refer to as the replacement for the T50P model.

Having done an extensive search for reviews of the T50P and finding very little, other than general agreement that the T50P’s bass is very light, my own experience with the DT-1350 tells me that Beyer fixed that little problem.  On the other hand, the sound of the DT-1350 from the midrange on up appears to be a repeat of the T50P’s sound, which prompted my investigation here.

Using Tyll Hertsen’s (formerly of headphone and amp seller ‘Headroom’) frequency response charts, and my own experience in correlating dips in the upper mids to lower highs with perceived detail in that area (or lack thereof), I’ve made the following list of headphones and the amount of drop in decibels from the midrange around 400 hz to the area from about 4000 to 7000 hz where each headphone has its greatest drop (or “suckout” as it is sometimes referred to).  For reference, the Sennheiser HD-800 has a drop of about 8 db, the Audeze LCD-2 has a 17 db drop, and the new HiFiMan HE-500 has a drop of 12 db.

I’ve made two tables, the first of which is sorted my manufacturer and model.  The second table is sorted by the drop in number of decibels.  In the second table I’ve drawn lines between “groups” to represent what I think of as “bright”, “normal”, “recessed”, and “depressed”.

These tables were formatted as plain text using the Courier fixed font, in case the columns don’t line up when viewed with a proportionally-spaced font.
Mids to Mid-Highs Drop by Manufacturer
————————————–
Audeze LCD-2            -17.0 db
Audio-Technica M50      -19.0 db
B&W P5                  -12.0 db
Beyerdynamic DT-1350    -25.0 db
Beyerdynamic DT-48E     -22.5 db
Beyerdynamic T1         -19.0 db
Beyerdynamic T50P       -25.0 db
Beyerdynamic T5P        -20.0 db
Denon D-2000            -09.0 db
HiFiMan HE-500          -12.0 db
HiFiMan HE-6            -07.5 db
Monster Beats Pro       -19.0 db
Sennheiser HD-25-1      -16.0 db
Sennheiser HD-800       -08.0 db
Sennheiser PX-100-II    -17.0 db
Mids to Mid-Highs Drop by Decibels
———————————-
HiFiMan HE-6            -07.5 db
Sennheiser HD-800       -08.0 db
Denon D-2000            -09.0 db
——————————–
B&W P5                  -12.0 db
HiFiMan HE-500          -12.0 db
——————————–
Sennheiser HD-25-1      -16.0 db
Audeze LCD-2            -17.0 db
Sennheiser PX-100-II    -17.0 db
Audio-Technica M50      -19.0 db
Beyerdynamic T1         -19.0 db
Monster Beats Pro       -19.0 db
Beyerdynamic T5P        -20.0 db
——————————–
Beyerdynamic DT-48E     -22.5 db
Beyerdynamic DT-1350    -25.0 db
Beyerdynamic T50P       -25.0 db

In addition to the above tables, I also did another comparison – of two headphones only – the Beyer DT-48E and DT-1350, in an effort to quantify the total and average amount of deviation from the anchor point (400 hz), and to try to get a feel for the smoothness of those deviations (i.e. the amount of change from measure point to measure point, as opposed to the amount of difference from each measure point to the anchor point).

In the table below, you can see that the total deviations (in absolute values) of the DT-48E add up to 94, and the DT-1350’s to 149.  But those are the deviations from the anchor point of 400 hz.  When you see that the measure-to-measure changes for the DT-48E add up to 88.5, and only 60 for the DT-1350, it appears that the DT-1350’s overall response from 400 to 11000 hz is smoother, albeit consistently lower in frequency from the anchor point.

When you consider that all of the better headphones exhibit the dips and choppiness in mid-upper frequency response that is shown in the measurement graphs, then obviously the data in each of those graphs could be “normalized” to subtract out the differences from an idealized response as graphed.  So, while Tyll Hertsen’s measurement graphs are extremely important and useful to at least partially validate what you hear in a particular headphone, there are several questions I think could be answered if someone would perform additional statistics on the data in those graphs.

Q: Is 400 hz a valid anchor or pivot point for measuring response deviations, or should that be set differently for each individual headphone? 

For example, if I moved the anchor point of the DT-1350 to 2000 hz, the total deviations would be 85 instead of 149.  2000 hz is probably too high, but it illustrates the point.

Q: If the data were normalized by subtracting out the deviations of an idealized response, would that make the results clearer or more accurate? 

At this point I don’t know, but I did perform a short test using the Sennheiser HD-800’s graph as the “ideal” response curve.  In this case, the DT-1350’s response matched the HD-800’s more closely than the DT-48’s did, which suggests that the deviation results noted above may not be as good a test as the smoothness and normalized-response tests.

Q: Would each headphone’s bass response have a mitigating effect on the results of tests performed on the mid-to-high frequencies, especially if the bass response were stronger than the midrange or anchor point? 

I would think so, but I don’t know at this point how that would work.

Frequency     DT-48E                    DT-1350
———     ———————     ———————

              Deviation    Change       Deviation    Change
              From         From         From         From
              400 hz       Previous     400 hz       Previous
              ——–     ——–     ——–     ——–
  600 hz      -02.5 db     02.5 db      -01.0 db     01.0 db

  800 hz      +02.5 db     05.0 db      -03.0 db     02.0 db

 1000 hz      +05.5 db     03.0 db      -05.0 db     02.0 db

 2000 hz      +06.5 db     01.0 db      -08.0 db     03.0 db

 3000 hz      -02.5 db     09.0 db      -16.0 db     08.0 db

 4000 hz      -07.0 db     04.5 db      -15.0 db     01.0 db

 5000 hz      -13.5 db     06.5 db      -15.0 db     00.0 db

 6000 hz      -22.5 db     09.0 db      -18.0 db     03.0 db

 7000 hz      -07.5 db     15.0 db      -23.0 db     05.0 db

 8000 hz      +07.5 db     15.0 db      -13.0 db     10.0 db

 9000 hz      +11.5 db     04.0 db      -03.0 db     10.0 db

10000 hz      -02.5 db     14.0 db      -11.0 db     08.0 db

11000 hz      -02.5 db     00.0 db      -18.0 db     07.0 db
————————————————————

Total of
Deviations
(Abs. Value)   94.0 db                  149.0 db

Total of
Changes From
Prev. Value    88.5 db                   60.0 db

8 Responses

  1. D_t_h_o_r_n

    Almost forgot the original questions. Between testing tasks, I may have a month of uninterrupted music listening.  Actually, even that stretch of time will have some tests going on.  Like right now I’m searching for a couple of good reference tracks that will definitively test the limits of the Apple iPod Touch, or maybe other DAP’s as well.  Modern headphones, getting more complex as they are with who-knows-what kinds of passive devices inside, present an interesting load to portable players, if not desktop amps as well.  That fact, plus what this article described, tells me that you just have to have a lot of patience and listen, and if you’re reviewing, take a lot of notes.  This process gets better when you get more experience, or maybe not because then you become more aware of the complexities of sound and audio engineering and all the compromises they have to make to get a product out the door.

    Psychoacoustics is a big part of testing and listening, but the anomalies and variances in what you hear can be smoothed out and made more predictable by repeating tests at different times of day, on different days, or with different techniques such as “what did I listen to just before doing this test?”  Listen to a bright headphone and switch to one that’s normal more-or-less, and it sounds dull at first.  So I learn to have patience and be willing to repeat tests over and over at different times to see how my impressions change.  One thing that has improved (I think so anyway) is my latest reviews don’t need as much revising as the earlier ones.  But I’ll never get it exactly right, and even if I did, remember the mfr’s disclaimer “Specifications are subject to change without notice.”  And they do sometimes.

    Reply
    • David.

      Good tracks? Try Muddy Waters – Folk Singer , track 6. Also Chesky did an album, with commentary before each track. P.M. me for more info if you like.
      Have you seen the post I did on the Beyer DT-1350 with pics showing the build and rewire ? Same as the T50s’, a rewire takes them to a much higher level. I have players, iPod Touch, QLS 350 (much underated),Colorfly C4 and the CK4. Also the Zoom recorder, surprisingly good on playback. Do not use FLAC files for serious testing, must use WAV. One last thing, I’m rapidly begining to think the trend towards hi-res files is a waste of time. Often a good 16/44 WAV can sound far better than say a 24/96 FLAC.

      Reply
  2. D_t_h_o_r_n

    This is the sort of thing I dread from a mfr. like Beyer. Besides the DT-1350, I bought a new DT-48E, and while I liked what they did to the sound, I did not like the way they wired it, with one wire in danger of being cut just adjusting the earcups with a socket driver (required for DT-48). I also bought 4 each DTX-300p’s, and only one survives, because I’m not using it. If you want to see how cheaply they can build a headphone, look at the 300p. But back to the DT-1350: I thought, given my experience with headphones of different mfr’s, the 1350 looked OK for the price. The greatest sin of the 1350 was the sound though – no matter who complains about the DT-48, it had and still has a very good midrange, unlike the newer DT-1350. Even the lowly DTX-300p, bad as it is, has a decent midrange if nothing else. I would like to see Beyer release something around $400 to $600 USD that has a good midrange, no big suckout in the upper mids ~5khz or so, and no huge peak just under 10 khz like the T70’s. Then it would make sense to me to refine their image for physical quality. There has been a huge demand lately for mfrs to make single-sided cables, and some mfrs are resisting that. Unfortunately, some of those who are not resisting are botching the work.

    Reply
  3. Anonymous

    So the T50P is in fact a much superior physical build internally? That is interesting indeed. I was and still am a fan of the T50p

    Reply
  4. Dave.

    How on earth do you manage to find time to enjoy music? How much of a time interval would you say is needed between listening to different phones? What about psychoacoustics? Can these be measured?

    Beyerdynamic DT1350 Build: Cheaper and flimsier than the T50s—they were much easier to reassemble.Damping pad fitted to 1350s , to compensate for thinner housing. Wiring: The pictures speak for themselves.Different wire than the T50s, but still 3 (Common Ground). instead of 4 conductors.  One sided cable quite bad enough—look at how much extra wire is in the way of one side as opposed to the other. But worse still there is a small circuit board glued inside the right housing, to terminate the three wires.So you have the left drive unit with an extra 55cm of cable (yes that’s 36.6% extra), and the right housing has a circuit board glued to it, which decreases the volume of the “Speaker”, and changes the resonant properties of the housing.In other words two different “experiences” for each ear. 

    Reply
  5. D_t_h_o_r_n

    Adding to this interesting problem is my recent acquisition of the Shure SRH-940. I did a long search for reviews and discussion of the 940, and I observed that many if not most of the people who tried the 940 found it to be bright, in many cases unusually so to the point of being irritating. In my initial tests leading to my review, I sort-of agreed to the brightness, and that it could be slightly irritating on tracks that had strong sibilants. A week later, in further reading of user experiences with the 940, I decided to make a new test comparing the Sennheiser HD-800 and the Shure 940 on tracks that had sibilant problems.

    What I found surprised me, The HD-800 was worse in every case! I eventually concluded that people (including myself) were forgiving the HD-800 and not the Shure 940, probably because of the price difference (the opposite of what logic suggests), and to some extent because of the way the HD-800 smears (bad word, I know) some high frequency details by bouncing the sound around more in those large earcups with the angled drivers.

    And the lesson I gained from this test was how to “listen around” the acoustic effects that the HD-800’s design imparts to the sound, so I can evaluate the musical tone underneath those effects and make a more accurate judgement of the basic sound quality, before applying the final judgement that takes the acoustic effects into consideration.

    Reply
    • Anonymous

      A solid case of “I bought it therefore I have to defend it’ from the HD800 crowd haha.. don’t discount the possibility of burn in and the amoeba effect Dale.

      Reply
      • D_t_h_o_r_n

        One thing seems certain, Marcus. If I could get the latest versions of all these headphones in front of me at the same time, fully burned in, I would definitely be able to tell the differences between all of them. Now that’s not likely to happen unless I win the lottery, but even then, I don’t think I could describe everything I hear in a way that would make perfect sense. It’s just too complicated. But that HD-800 thing – that big sound from those huge earcups really teases you away from any harsh criticism. (Disclaimer note to Sennheiser: Hey, I’m not criticizing, just fantasizing.)

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