I finally got the Gold Planar GL400 (open version). Took six weeks to arrive. I guess Covid-19 is still affecting the deliviries.
Since there is little information availaible on these headphones I'll start by correcting what has been written about these headphones elsewhere. There is a review that states "You get a well-padded headband with a good albeit plastic mechanism to adjust for sizing. The earcups swivel and pivot which aids the comfort somewhat. " First of all the slider mechanism is made of metal, not plastic. What is more important is that earcups
do not pivot. The cups swivel 180 degrees so you can lay them flat but the
cups do not pivot. To make it clear by pivoting I mean the vertical movement of the cups which makes them adjust to your headshape.
Cups on Beyerdynamic T1 tilt freely to achieve proper fit.
Allmost all headphones do that to some extent because without pivot mechanism it is unlikely most people get a comfortable fit. GL400 and Martin Logan Mikros 90 are only headphones I can think of that have no pivot mechanism whatsoever. Kind of makes me wonder how someone who reviews headphones professionally can miss something like that.
As you can see from this inside pic there is no hidden mechanism that allows the cups to tilt.
So why am I making such a big fuzz about lack of this pivot mechanism?
1) This design makes the headphones extremely uncomfortable
2) It affects sound quality in a very negative way
These are propably the most uncomfortable headphones I've ever had. Generally I don't even find on-ear headphones uncomfortable. The clamping force is concentrated mostly on the upper portion of the ear.
Look how it fits on my measurement kit.
It is a pain to wear and it also leaves lower parts lacking seal which of course affects sound quality. GL400 sounds hollow and depending on seal issues can lack bass. It sounds like listening to music through a metal tube. Loudness like, fatiquing, reverby mess. Upper treble is severely recessed. Cymbals lack shimmer and presentation in general is lacking air. Lot of these negatives could have been avoided with a pivot system. When I push the cups near my jaw things clear up nicely. Bass is still soft and loose sounding for a planar but midrange clarity is improved so much that I think these headphones actually have potential. Treble is still quite nonexistent no matter what I do.
Few words about earpads... Stupid fixed headband system is not the only culprit when it comes to lack of comfort. Earpads suck. Pads look quite nice on pictures but the foam inside is too soft and the actual soft part of the pads is only about half of what you'd guess by looking at them.
This is the actual thickness of the earpads
I wanted to do some measurements but on ear headphones are always tricky with mini dps ears. It is even more tricky with headphones like gl400 that don't adapt to headshape at all. So I taped the headphones on the measurement rig.
So the measurement is iffy at best. However that is pretty much how it sounds to my ears. Shouty, loudness like midrange lacking any higher frequencies. Channel balance is nice but because of the tape job I did that can't be trusted.
These headphones could have potential with different headband and more comfortable earpads. Some mods to bring out the highs and lower the 1khz-3khz region to tone down the shouty loudness effect. Frequency response has no weird dips or peaks. I can't think of a cheap headphone that is so linear. It has great bass extension down to 20hz. If someone came up with proper mods these could easily be the best headphones under $100. Technicalities are there but I'm kind of pissed that Gold Planar released this mess that is more like a prototype than a finished product.
The housing they used on this headphone is a generic one. I had dick smith vt-h68's which look a lot like and those had a all metal housing. On gl400 cups are plastic. So they took a very plain design and downgraded from metal to plastic. Many major brands use this design.
I can't say for certain but if gold planar got their parts from Shenzhen Vtsonic they should have atleast used the better model vt-h63. If this sounds or looks familiar it's because not long ago I recommended rebrand kit sound milano in this thread. GL400 with those pads and pivot function could have been a homerun.
Stil... if someone want's to give GL400 a go, good news is that ear pads can easily be replaced. Attachement ring is not glued on so you can use any pads you like that are about the right size.
Other things:
- Very light for a planar. Reported weight is 160g.
- Cable is microphonic
- Quite easy to drive, straight out of a oneplus 6 it was decent.
The pad rolling. It was a bit shame that Hifiman did not give us a suck option for the Deva. Of course u can attach anything with time, a glue/tape or even 3D print mounting rings.
If this is the real frequency response... 
