beyer T50p: beyerdynamic Announces The T50p Portable Tesla Headphones - Page 48

So true. In fact, I recall seeing a graph that showed what the ideal headphone response should be and it was far from flat, there was a huge dip in the upper midrange. My favourite headphones have a very ragged response on a graph. The ones that come closest to a flat response are the most dull and boring.
 

Would you happen to recall a link to that ideal FRC?

Wasn't this ideal FR for only one person ? As I think it may be different for everyone...

"Ideal" would be a smooth peak around 100 Hz, a smooth flat line up to treble frequencies and a soft -5 dB roll-off around 10 kHz or so.

Take a look at the HD600 FR to get a rough idea..

 

Anyway, that upper bass / lower midrange peak calls for muddiness and -15 dB in the high mids kills any possibility to make this can sound natural.

When applying a similar curve with an EQ it sounds like the music is coming from the room next door.

Edited by xnor - 10/3/10 at 9:25am

Re the graph, I agree with someone else (Skylab??) who queried whether the cans were placed correctly on the dummy head when the readings were taken...

 

The Beyers are nothing short of fiddly to get to the sweet spot, and - if not put on correctly, can have all manner of tonal shifts pop up...

 

I certainly don't hear wild spikes like that when they're in the sweet spot on my head...

I guess it is...see below

 

Yes, that "ideal" FR is what HeadRoom and Etymotic Research suggest anyway and I agree. :P

I also can't think it outside the realm of possibility that the t50p wasn't fitted properly to the Headroom head. Does he have a name? 

 

With these cans, how do you know from site that are properly fitted? You don't. You know by sound. They're not so fiddly on me and tend to want to fit normally to my ears anyway, so it's not an issue. But then again other bigger supra-aurals that people love tend to be too big for my ears and more fiddly. Not circumaural, just more fiddly.

 

But accurate graph or not, if they sound good, they are good.

Taken from the beyer dynamic website, I found this very revealing (also mind the last clause!):

 

What is diffuse-field equalisation?

Have you ever wondered why a frequency response curve is almost never included with headphones? I can let you in on the secret: they look terrible! Such an erratic frequency response graph would hardly encourage customers to make a purchase. What the customer wants in the end is something that is linear. Uncoloured. Solid.

But why do these frequency response curves look so horrible? And why do you not clearly hear these glaring leaps and drop-offs?

 

How we hear

From childhood on, humans are accustomed to perceiving acoustic events. We grow up with a variety of sound sources and get used to them. The baby rattle, the clatter of dishes from the kitchen, pedestrians on the street, music from loudspeakers, etc. – all of these sound sources have something in common: they are located relatively far from the ear.

Before the sound from these sources reaches our eardrum, it is coloured by the shape of our head and our ear. Depending on the angle, many frequencies are accentuated and others are attenuated. With time, we learn these frequency patterns and are able to do things such as recognise the direction in which the sound source is located. Therefore, we do not hear sound as it was produced at the source, but instead in coloured form.

 

Loudspeakers and headphones

When we listen to music over loudspeakers with a linear frequency response curve, we are actually hearing a spectrum that is influenced by the distinctive shape of our head. We perceive this as linear.

When listening with headphones, the headphones do not even try to generate any effects on the outer ear, since the sound source is so close to the ear. What comes out of the headphones arrives at the eardrum in relatively uncoloured form. In order for the headphones to still sound natural, the sound must be coloured so that it is as similar as possible to the colourations caused by the shape of the head and ear. In other words, the headphones must have the frequency response set so that it sounds like the sound is coming from a distant source.

 

Diffuse-field equalisation

In order to adjust headphones to our listening habits, we must first use technical means to measure the colourations caused by our head. For example, an artificial head with microphones in the ears is used. When this artificial head is exposed to sound, you can use the microphones to measure how the sound would be perceived by us instead of the artificial head.

So that the headphones do not have a sound that always seems to come from one direction, but instead can reproduce all sound directions equally, the artificial head must be exposed to sound from many directions and the result averaged. This does not perfectly reproduce any direction perfectly, but no direction is completely suppressed. 

At beyerdynamic, there is an echo chamber for this purpose. It is a small, five-sided room with acoustic sails on the ceiling that looks quite bare and empty. The fascinating thing about it is that, although it is the size of child’s room, it sounds like a cathedral! An octahedron loudspeaker that radiates sound in eight directions is in one corner. If you are far enough away from the loudspeaker, the strong echo causes you to no longer be in the direct field, but instead in the diffuse field of the loudspeaker, i.e. the area in which the sound reflected off the walls is louder than the sound that is coming directly from the loudspeaker.

If artificial head measurements are carried out in this chamber, many sound directions overlap due to the echo, allowing us to obtain the required averaging. This averaging (the measurement in the diffuse field) gives diffuse field equalisation its name.

In order to equalise the headphones, they are placed on the artificial head and the frequency response is adjusted so that the measured frequency behaviour corresponds to that of the diffuse field.

 

Discussion

Since the mechanical and electronic options for changing the frequency response of headphones are limited, the equalisation cannot be carried out perfectly. Different headphones are also adjusted to various tastes. It is by no means the case that all diffuse-field equalised headphones sound the same. In addition, the frequency patterns for directional hearing depend on the shape of the head and ears. For this reason, they are a little different for everyone. Hence, measuring with an artificial head is a pretty arbitrary choice.

Diffuse-field equalisation is therefore an important part of improving localisation with headphones and avoiding “in-head localisation”, but it is not guaranteed to work and is no replacement for extensive test listening.

Thanks for pasting that text! I like their philosophy and the fruit has been great sounding headphones. 

Definitely a problem with dummy head measuring systems. The problem is, that you can't just calibrate the head. You have to calibrate the apparent perception as well... that was more difficult than I thought it would be when I rented the heads. Especially as in Headroom's case, too many people who have never heard whatever phone is in question drawing their 'knowledge' from the graphs.

 

 

I do sometimes wonder why headphone manufacturers, given that they present sweet FA in this respect on their sides, don't offer more support to premier vendors like Headroom. Or do they, and are they being numpties as well?

Here's one of the better explanations of the difficulties and different approaches to designing and measuring headphones that should answer many questions:

 

http://www.stereophile.com/features/808head/

 

Read and understand and you too will be a headphone expert...

 

Kevin

Anyway, there were first impressions and short reviews in the german hifi forum long before those graphs existed and the guys were not impressed, actually some impressions line up well with what can be seen in the measurement.

However, it still may sound good to you, which is ok.

Edited by xnor - 10/14/10 at 4:52am

...let's not forget the issue with placement on the ear...

My impressions from the first few days of owning these were of absolute disappointment, how I was wearing them did not put that little tiny sweet spot into play...

...I can still make them sound bad, so I don't believe my change of heart is anything to do with familiarisation... And when comparing to the Senn HD25, they still sound the same...

...that is going to be another one of those arguments that will always have people on both sides of the fence, personally, I am glad that I found the love, but even if I had not, I knew I could sell them on easily

Awaiting delivery of the T 50 P next week ... I'm dying with suspense (I already own the DT 880 Pro ... and it is awesome)