[eric65]

Hello everyone.

If, in the opinion of the majority (?) (*), the Sennheiser HD-600 (2021) is a headphone that, tonally speaking, borders on perfection (note: technically speaking, there are even better than this electrodynamic headphone, especially with the very good planar and e-stat headphones), well, I find that the COSMO equipped with the PARA's hybrid pads defends itself quite well for tonality, at least on this FR curve.

(*) At least by the famous headphone critic Crinacle, who said of the HD-600: "Neutral - The legendary neutral reference. Slightly better clarity and imaging than the HD650."

For perfectionists: equalize the small level bump at 3 KHz with an EQ, and you'll have a near-perfect headphone.

That said, as expressed in the French forum here: https://www.homecinema-fr.com/forum/post181376108.html#p181376108 or on head-fi (at the end of the post), here: https://www.head-fi.org/threads/moo...nar-new-flagship.970569/page-24#post-18082352

To the question posed by a compatriot about COSMO : " It's still stupid that they didn't just use the original Para's pads... What were the designers thinking? Didn't they even have the idea of doing the same test as eric65? "

I replied: "That's a very good question; I'm asking it myself".

The only way for Moondrop to make up for lost time would be to deliver a second pair of pads with the COSMO, the PARA's hybrid pads (which don't cost much); they've already done this with the PARA (which costs only 300 Euros) and which has two pairs of pads: the excellent hybrid stock pads and a second pair of leather (or imitation leather) pads (not very convincing for the latter). https://boizoff.com/language/en/moondrop-para-headphones-review/

 

[eric65]

Hello everyone.

Concerning the technicality of the COSMO versus other planar headphones, such as the VENUS and the Susvara, if we consider that the mass of the moving equipment (which is the sum of the mass of the plastic film of the diaphragm + the mass of the metal's traces covering the diaphragm) is a major element for the resolution of the headphone; and if we weight this moving-crew mass against the same (equivalent) surface area of the diaphragm of the drivers under consideration, we can assume that the moving mass of the COSMO diaphragm (plastic film + pure silver metal traces), for the same surface area of the diaphragm, is 7.8 times less than that of the VENUS.

And the Susvara?

Assuming further sarting assumptions, the Susvara's movable diaphragm mass (plastic film + gold metal traces), for the same surface area of the diaphragm, is only 1.2 times less than that of the COSMO (and 9.4 times less than that of the VENUS).

If the initial hypotheses are correct, for an equal planar diaphragm surface (if we weigh the same diaphragm surface for both drivers), the COSMO is almost equal to the Susvara in terms of moving mass (moving mass ratio of only 1.2 in favor of Susvara) and much better than the VENUS (moving mass ratio of 7.8 in favor of COSMO).

Note: The details of the starting hypotheses and the calculations (and parameters used) can be consulted on the French forum, here: https://www.homecinema-fr.com/forum/post181376395.html#p181376395 ; take your best calculator to check the calculations.


EDIT: By a calculation method totally independent of the method used on the French forum , which started from the assumption that the thickness of the pure silver traces of the VENUS was (would be) 1 um thick (manufacturer's data), and that visu, the VENUS silver traces were three times longer (because there were 3 x more of them) and also 5 x less wide (measured on the attached photos below (in spoiler)) than those of the COSMO, bearing in mind that the two drivers are the same size (100 mm) and that the VENUS has an electrical impedance of 18 Ohm (compared with 15 Ohm for the COSMO) ; my first conclusion was that the COSMO's silver traces were 3 x 5 x 15/18 = 12. 5 times thinner than that of the VENUS, i.e. a thickness of only 1/12.5 = 0.08 um (= 80 nm) (if the thickness of the silver traces covering the VENUS diaphragm is indeed 1 um, which I had not yet verified by an independent calculation).

Using a method completely independent of the above, it's very easy to calculate the actual silver tracks thickness (in mm) of the VENUS (and also of the COSMO) independently of the manufacturer's data, simply by knowing the resistivity of silver (which is 0.0159 Ohm*mm²/m), the measured length (in meter) of the VENUS and COSMO driver silver tracks and their width (in mm) (which can be measured with a decimeter from these two images of the 100 mm drivers of the VENUS and COSMO, in spoiler below).

Spoiler

Electrical tracks (in pure silver) of the VENUS diaphragm (18 Ohm impedance and 100 mm in diameter): pure silver tracks a priori three times longer (and numerous) and 5 times narrower, and by electrical deduction 12.5 times thicker than those of COSMO.

Electrical tracks (in pure silver) of the COSMO diaphragm (15 Ohm impedance and 100 mm in diameter): pure silver tracks a priori three times shorter (and numerous) and 5 times wider, and by electrical deduction 12.5 times thinner than those of the VENUS.

I measured the length of the silver track on a VENUS at about 2 m..
I measured a COSMO's silver track length at about 0.666 m.
I measured a silver track width at about 1.4 mm for the VENUS.
I measured a silver track width at about 7 mm for the COSMO.
(Note: COSMO tracks 3 times shorter and 5 times wider than those of the VENUS).

The impedance (electrical circuit resistance) of the COSMO is 15 Ohm and that of the VENUS is 18 Ohm.

Using all the above parameters, and independently of the manufacturer's data (apart from the impedance of the headphones), we can easily calculate the thickness of the silver traces on the two headphones, which is:

For the VENUS: silver track thickness = 0.0159 (electrical resistivity of silver in Ohm*mm2/m) x 2 (length in meter of VENUS silver tracks) / (18 (impedance in Ohm of VENUS) x 1.4 (width in mm of VENUS silver tracks)) = 0.00126 mm (i.e. 1.26 um thick) (value very close to the 1 um thickness given by the manufacturer).

For the COSMO: silver track thickness = 0.0159 (electrical resistivity of silver in Ohm*mm²/m) x 0.666 (length in meter of COSMO silver tracks) / (15 (impedance in Ohm of the COSMO) x 7 (width in mm of COSMO silver tracks)) = 0.0001 mm (i.e. 0. 1 um thick, i.e. 100 nm).

Note: this last and independant calculate value : 100 nm, for the silver track thikness of the COSMO, is very close to the 80 nm value I had originally found, based on the official VENUS silver track thickness of 1 um; the thickness of COSMO's silver track being 12.5 times thinner than that of VENUS.

This last calculation show that VENUS's silver tracks would in fact be slightly thicker, calculated at 1.26 um (instead of the manufacturer's 1 um).

In the case of the Susvara, the first method of calculation concluded that the Susvara's metallic gold traces were 2.6 times thinner than the COSMO's pure silver traces (bearing in mind that gold weighs almost twice as much as silver): i.e. an estimated thickness of 80/2. 6 = 30 nm (if COSMO's trace silver thickness is 80 nm and VENUS' 1000 nm (1 um)); and more likely an actual thickness of 100/2.6 = 38 nm, for the golden tracks of Susvara, if COSMO's trace silver thickness is more like 100 nm (0.1 um) and VENUS's trace silver thickness is more like 1260 nm (1.26 um), as the latest calculations (independent of the first) seem to indicate.

 

[eric65]

Hello everyone.

A quick word about the Moondrop EP-100A hybrid pads that can be found for less than $30 here and here :
https://shenzhenaudio.com/products/moondrop-ep-100a-openback-earpad
https://hifigo.com/products/moondrop-ep-100a

and are designed to upgrade the stock hybrid pads of the Moondrop PARA planar headphone.

They're really different from the PARA's hybrid stock pads.

The dimensions of the EP-100A pads are identical (they are replacement and upgrade pads for the PARA).

Spoiler

However, the materials used are not at all the same:
The leather edges of the hybrid EP-100A pads are made of genuine sheepskin leather; non-microperforated leather on the inside of the pads (see photo below), whereas the edges of the PARA stock hybrid pads are made of imitation leather, microperforated on the inside of the pads (see second photo below).

Spoiler

Moondrop hybrid EP-100A pads. Sheepskin replacement earpads (not microperforated internally). For Moondrop PARA headphones.

Hybrid pads fitted in stock to the excellent Moondrop PARA planar headphones. Imitation leather, microperforated internally.

What's more, the internal foam of the pads is different: firmer for the EP-100 A hybrid pads; softer for the PARA hybrid pads.
EP-100A hybrid pads therefore have a firmer consistency than PARA's hybrid stock pads.

The frequency response of the PARA equipped with EP-100A upgrade pads is different from the frequency response of the same PARA headphone equipped with its stock pads, as you can see in the photo below.

Spoiler

Listening, I find that my PARA headphones re-equipped with these EP-100 A hybrid upgrade pads (+ Moondrop UP upgrade cable) sound better than with their stock hybrid pads (+ UP upgrade cable), in the sense that they're a little less bright in the treble. As a result, it can be listened to a little louder, and the bass (which sinks very low) comes through comparatively better, with a little more level.
The sound is really great, and the price/performance ratio of the PARA, even “retrofitted” with these EP-100A upgrade pads, is unbeatable.

As for the COSMO, when I listen to it, I still have a slight preference for the PARA's stock hybrid pads for the extra treble (and aeration) provided by these PARA's hybrid stock pads compared with the EP-100A hybrid pads (which provide a little less treble), and much more than with the stock COSMO's stock pads (which I don't like at all), which attenuate the high frequencies too much and provide an unpleasant level bump to hear at 1 - 1.5 KHz).
(note: EP-100 A hybrid pads which go very well with the PARA, and a little less well so with the COSMO for my hearing, which is not necessarily yours).

Spoiler

Moondrop COSMO's FR (with its stock pads) versus Moondrop PARA's FR with its stock hybrid pads.
Unfortunately there are no FR measurements made on this site with the EP-100A hybrid pads which, for the PARA headphone, a priori provide a little less treble than the stock hybrid pads.

PS: for French speakers (in spoiler).

Spoiler

For French speakers who follow me on head-fi, you should know that I have unsubscribed from the French forum due to a censor who knows nothing about science.
Use your favorite translator (google translator and even better DeepL Translator) to follow me here .

 

[vicenzajay]

I'll poke the bear again here - any specific recommendations for replacement earpads for the Venus that don't destroy its RF response?

Every 10 posts or so there's a question about this (through the last few pages), but apart from a reference to "any ZMF pad", I'm not sure I read a specific recommendation.