[hrklg01]

I think harmonic distortion measurements – maybe displaying the different orders – would be the best indicator. Better than optical indicators such as oscillograms lacking the necessary resolution .

[ at 90dBSPL in average] amplitude & Distortion THD + K2+K3:

[ at 90dBSPL in average] Distortion THD + K2 up to K6+:

 

[Muinarc]

The THD rise in the lower frequencies looks a lot like the graphs I've seen for the AKG k812. Interesting stuff, thanks for sharing Heinz.

 

[JaZZ]

Thanks, Heinz, I really appreciate your effort!

Since the percentages don't refer to the actual tone at the respective frequency (from what I get), but the average loudness level of the whole frequency response, the actual value for 35 Hz (e.g.) would be something like 27% total distortion, right? (Correct me if I'm wrong!) Or is it that the tone at 35 Hz is just ~87 dB instead of the average 90 dB?

Now 90 or even 87 dB is already really loud, but from the further increase at 100 dB we could deduce how much equalizing below 50 Hz is possible or recommendable. (As for myself, I would do it anyway, but probably limited to 25 or 30 Hz.)

 

[hrklg01]

The 60mW max is a value delivering ~96dBSPL on the ear already.
We want to secure customers only.
There is no technical- but legal reason behind.
BR heinz

 

[hrklg01]

About additional equalizing:
A dynamic system has the maximum membrane excursion at the fundamental resonance which is 50Hz for Mysphere 3.x
Below the excursion is not less, but the SPL reduce because the air has to be accelerated at the same level if the same SPL is wanted.
(This is true for totally open systems only!)
This lead to the fact, that if additional EQ is used, the max. excursion will be exceeded once.
So additional EQ-ing at very low frequencies is fine, but not when high SPL is wanted.
BR heinz

 

[JaZZ]

I seem to have confused a few things, and from your last post you seem to have misinterpreted my question. However, the most useful procedure in the context at hand would be if you could equalize the headphone yourself to flat down to 20 Hz and measure harmonic distortion in this configuration. (I know, that's quite a barefaced demand.)

 

[Dobrescu George]

I think the distortion figures look excellent!

About Equalizing the Sub-Bass, I don think it would add any distortion, but since the distortion figures were at loud SPLs, I think that @hrklg01 was trying to say that adding more sub-bass at that high level, it could induce clipping, while at lower SPLs it shouldn't change the distortion figures. I might be wrong there.

 

[JaZZ]

Hi George

Have a look at Inner Fidelity's graphs! All of them confirm that harmonic distortion increases with membrane excursion, particularly in the low bass – which is quite logical, since there comes the moment when with every further increase of excursion mechanical resistance will grow disproportionally.

 

[Matrix Petka]

Hello,
To use back open or even totally open (like Mysphere) headphones close to hard surfaces, the sound will be effected negatively by resonances heavily.
When you use it close to a cushion of the bed or similar use, the mid and mid-high frequencies are still effected, but not that much due to the damping effect of the cushion material.
To be honest, I personally use Mysphere3.1 very often in this way and the brain seems to become used to it....
BR heinz

Sometimes it is good to sacrifice some quality in the sake of comfort. We are listening music for max pleasure

 

[Dobrescu George]

Hi George

Have a look at Inner Fidelity's graphs! All of them confirm that harmonic distortion increases with membrane excursion, particularly in the low bass – which is quite logical, since there comes the moment when with every further increase of excursion mechanical resistance will grow disproportionally.

Oh, I see what you meant about the measurement there!

 

[qazxsw80]

Hello,
The slim transport case (in the middle of the table between the two big boxes) will look similar like the standard packing. The difference is mainly the height and that the headphone parts (drivers and bow) are placed dismantled into to allow the slim form factor

Heinz, is there a reason why you decided to make a metal case for the Mysphere (at least it seems that way in the picture)? What I mean, maybe I wrong, but It seems to me that most people strongly prefer carrying cases and metal ones are more suitable for storing, than carrying. For example, the Beyerdynamic T1 1st gen. had the metal case -

And everyone I know didn't like it. They thought it was heavy, not really transportable and almost useless. And it seems to me that guys at Beyerdynamic realized it too and that's why they replaced it with the new one -

And most people like it much more. So, maybe, It would be better to make something like the case from Ultrasone -

 

[hrklg01]

About the slim transport case:
Basically you are right - this case is very robust as well. We think that's even more important for a transport case as for the storage case.
Only parts are our of metal and enforce mainly the edges of this packing.
So I suggest to try and check it out when we are ready...
Best regards,
heinz

 

[greenmountain]

About additional equalizing:
A dynamic system has the maximum membrane excursion at the fundamental resonance which is 50Hz for Mysphere 3.x
Below the excursion is not less, but the SPL reduce because the air has to be accelerated at the same level if the same SPL is wanted.
(This is true for totally open systems only!)
This lead to the fact, that if additional EQ is used, the max. excursion will be exceeded once.
So additional EQ-ing at very low frequencies is fine, but not when high SPL is wanted.
BR heinz

I quite understand but it would be good to have some guide lines to know how much eq is admissible especially below 50Hz. Of course there will be the problem of translating SPL to amp out put (the easiest would be to measure output voltage).
The distortion figures look excellent especially considering that the human ear is most sensitive to distortion at lower sound level (max 60-80dB).

 

[hrklg01]

@greenmountain

I quite understand but it would be good to have some guide lines to know how much eq is admissible especially below 50Hz. Of course there will be the problem of translating SPL to amp out put (the easiest would be to measure output voltage).
The distortion figures look excellent especially considering that the human ear is most sensitive to distortion at lower sound level (max 60-80dB).

Thank you for the idea!
Ok, I'll give you a kind of table of maximum voltage to be applied for a series of frequencies...
Please give me some time!
Mille Grazie!
heinz

 

[hrklg01]

Here is a list about maximum voltage [RMS] usable for Mysphere 3.1
For all the "EQ-gamers"
Please understand that this list of voltage shows only the capability of Mysphere to be applicable to play in a technical safe mode for the product.
This voltage does not mean to be applied for any long listening session because of potential hearing damage!
The voltage are RMS = mid value ofa sine frequency. Impulses can be applied with higher voltage....
KR heinz