[Kerry56]

I recently purchased these HE-R9 headphones, for the heavily discounted price of $109, and even at that price I wasn't really pleased with their sound. They were odd headphones, with good sound on certain tracks, and some awful results on others. The main problem was a boomy sound in the bass/lower mids that could overwhelm everything else.

You can see them here: https://store.hifiman.com/index.php/he-r9.html or here: https://www.head-fi.org/threads/introducing-the-hifiman-he-r9.961867/

The interior of those huge cups is angled away from the driver, but the driver itself sits square, parallel to your ear. Hifiman has a thin sheet of foam directly behind the driver, but nothing else. It is a big, cavernous space, with lots of reflective surfaces. My first thought was to line the interior with foam and see if that made a difference. The result? Possibly better, but it was a minor change in the sound. I found that EQ was a better solution, but even there, I wasn't satisfied with what I was getting out of the headphone.

So, naturally, I decided to dive headfirst into modding these things. Might as well. I had a thick piece of cherry in my shop, and I decided it would make a couple of cups for this headphone. There was one interesting problem in the way. I have been a woodworker most of my life, but never a wood turner. I haven't got a lathe. So, making round blanks to a specific size was a challenge. I wouldn't advise turning your drill press into a makeshift lathe, but it does work. Once I had the blanks, it was easy to cut and shape them on my router table. They aren't spectacular cups, since the wood I used is just plain cherry, and not figured wood, but they are good enough for my purposes.

The original cups fit together on the driver housings with a little lip that I couldn't reproduce on my wooden cups, and this turned out to be a happy accident. Screwing the wooden cups on the housings leaves a small gap, which makes these headphones semi-open now, instead of closed back. And I believe this is the key to the better sound I'm getting. The straight space behind the driver (instead of the original angled space) did change the sound, and perhaps the wood helps too, but I'm pretty sure the drivers are doing a better job with a little more air.

There are downsides. The cups I made weigh about 96 grams each, while the original plastic cups were 39 grams. So, they are heavier overall. There is less isolation, and I believe, slightly less bass impact. I need to do more testing to be sure of that.

Here's what they look like:

 

[Carlos Dias]

I recently purchased these HE-R9 headphones, for the heavily discounted price of $109, and even at that price I wasn't really pleased with their sound. They were odd headphones, with good sound on certain tracks, and then producing some awful sound on others. The main problem was a boomy sound in the bass/lower mids that could overwhelm everything else.

You can see them here: https://store.hifiman.com/index.php/he-r9.html

The interior of those huge cups is angled away from the driver, but the driver itself sits square, parallel to your ear. Hifiman has a thin sheet of foam directly behind the driver, but nothing else. It is a big, cavernous space, with lots of reflective surfaces. My first thought was to line the interior with foam and see if that made a difference. The result? Possibly better, but it was a minor change in the sound. I found that EQ was a better solution, but even there, I wasn't satisfied with what I was getting out of the headphone.

So, naturally, I decided to dive headfirst into modding these things. Might as well. I had a thick piece of cherry in my shop, and I decided it would make a couple of cups for this headphone. There was one interesting problem in the way. I have been a woodworker most of my life, but never a wood turner. I haven't got a lathe. So, making round blanks to a specific size was a challenge. I wouldn't advise turning your drill press into a makeshift lathe, but it does work. Once I had the blanks, it was easy to cut and shape them in my router table. They aren't spectacular cups, since it's just plain cherry, and not figured wood, but good enough for my purposes.

The original cups fit together on the driver housings with a little lip, that I couldn't reproduce on my wooden cups, and this turned out to be a happy accident. Screwing the wooden cups on the housings leaves a little gap, which makes these headphones semi-open now, instead of closed back. And I believe this is the key to the better sound I'm getting now. The straight space behind the driver did change the sound also, and perhaps the wood helps too, but I'm pretty sure the drivers are doing a better job with a little more air.

There are downsides. The cups I made weigh about 96 grams each, while the original plastic cups were 39 grams. So, they are heavier. There is less isolation, and I believe, slightly less bass impact. I need to do more testing to be sure of that.

Here's what they look like:

 

[Carlos Dias]

Bem feito!

 

[Carlos Dias]

Well done!

 

[Carlos Dias]

 

[Hyde00]

Nice! Reminds me a lot of Lawton cups on Fostex headphones.

 

[Kerry56]

Still fine tuning these. The bass is definitely reduced, and this version of the HE-R9 can no longer be considered a bass-head type of headphone. It's pretty close to what I want though, since the bass hits without being intrusive, boomy or bloated.

I was getting some unexpected treble spikes, so I started experimenting with different materials in front of the drivers. The felt I'm using now is working better than I expected.

 

[Kerry56]

More experiments... this time with different pads. The original, hybrid pads are not too bad, but I was looking for ways to improve the sound. Pleathor pads were not good, and took the sound in the exact opposite direction that I wanted. I had some Brainwavz velour pads on another headphone, so that was my next step, and I like the sound they produce, even if they are only temporarily stuck on the headphones with double stick tape. They seem to clear up a little more congestion in the upper bass and lower mids. I'm going to order a set of the oval velour pads from Brainwavz, but I have to find a way to attach them permanently. I can make a mounting ring, but there is very little space at the top where the arms of the headband fit, and so the normal method of attaching this type of pad will be problematic.

I know that Hifiman makes mounting rings for their round headphones, but I haven't seen any for their oval ones. Though I am loath to give Hifiman any more money, I can hold my nose and order from them if there are any available. It would save some time and head-scratching. Does anyone know if they exist and where I can find them?

By the way, many of the Brainwavz pads are on sale right now, and the ones I'm ordering are only $11.99.

 

[Hyde00]

Yeah I wish Hifiman made their pad mount more universal, I think they have like 3-4 different styles of mounting system across their line of headphones.

In comparison Fostex line is mostly the same style.

 

[pbui44]

I know that Hifiman makes mounting rings for their round headphones, but I haven't seen any for their oval ones. Though I am loath to give Hifiman any more money, I can hold my nose and order from them if there are any available. It would save some time and head-scratching. Does anyone know if they exist and where I can find them?

I ordered the perforated sheepskin leather ones for my MD x Hifiman Edition XX last year from here and they still work great, so these should work for the HE-R9 as well with the perforated sheepskin leather model being the priciest at just under $16:

https://www.aliexpress.us/item/3256805134095660.html

 

[Kerry56]

The Brainwavz velour pads arrived, and I made a mounting ring system for them. With this in place, I can use any oval pad that has the same type of attachment... in other words, any pad with the little flap of vinyl that fits into a slot or stretches over the cup.

Since I had to wait for the pads, I was using my CAL! for the last few days, and going straight from my CAL! to this modified HE-R9 shows me that I haven't tamed the bass entirely. That might not be possible, and these headphones will always be a "fun" set, and will never have super resolution and clarity.

I don't intend to do many more physical adjustments in the near future. Doing everything by ear is difficult. Making minor changes and looking at the frequency response charts would be much easier, but I don't have a testing rig, and don't feel like spending $300 to get one. I'll take a few days listening to what I have now, and maybe I'll try doing a few adjustments through EQ.

In any case, I much prefer the current sound compared to the original. I don't think I could have adjusted the sound to a acceptable level while using the original cups. Look at JM Audio Editions. They modify headphones as a business, with a lot more equipment and experience than I have, and it has taken 8 iterations of their mods to come to a result they think is good while using those original cups. Doing that by yourself would be an exercise in frustration.

All my mods are reversible. If I needed to put these back in the original configuration, I could do so, but I don't think that is going to happen, not if I am the one listening to them. So, is there anything I'd do differently? Absolutely. I've already made one small change, by removing the felt over the driver. Didn't need it with these velour pads for some odd reason that I can't really explain. But there are a few other changes I'd make. The pad mounting system I made is egg-shaped, but I could have extended it a little more towards the bottom of the cup. Didn't know beforehand if the pad's vinyl flap would stretch enough, but it would have. Also, when I cut the interior of the cups on my router table, I was making blind cuts, and was very conservative on depth. I could have shaved off another 10 or 12 grams of weight from each cup. That's ok. It was a learning process, and I'll remember that if I ever make another set.

Hope this has been informative, or at least, entertaining.

Edit: Didn't take long to come to the conclusion that the velour pads weren't working all that well. Oh well, that's par for the course when experimenting. I'm back to the original pads now. I'll use the Brainwavz velours on a different headphone.

 

[Hyde00]

I used to mod Denon/Fostex headphones and it's a lot of trial and error.

Cup wood material, cup dampen material, ear pad shape, earpad thickness, ear pad volume....etc. all can effect the sound.

So I stopped modding heapdjones LOL.

 

[Riversalt]

The Brainwavz velour pads arrived, and I made a mounting ring system for them. With this in place, I can use any oval pad that has the same type of attachment... in other words, any pad with the little flap of vinyl that fits into a slot or stretches over the cup.

Since I had to wait for the pads, I was using my CAL! for the last few days, and going straight from my CAL! to this modified HE-R9 shows me that I haven't tamed the bass entirely. That might not be possible, and these headphones will always be a "fun" set, and will never have super resolution and clarity.

I don't intend to do many more physical adjustments in the near future. Doing everything by ear is difficult. Making minor changes and looking at the frequency response charts would be much easier, but I don't have a testing rig, and don't feel like spending $300 to get one. I'll take a few days listening to what I have now, and maybe I'll try doing a few adjustments through EQ.

In any case, I much prefer the current sound compared to the original. I don't think I could have adjusted the sound to a acceptable level while using the original cups. Look at JM Audio Editions. They modify headphones as a business, with a lot more equipment and experience than I have, and it has taken 8 iterations of their mods to come to a result they think is good while using those original cups. Doing that by yourself would be an exercise in frustration.

All my mods are reversible. If I needed to put these back in the original configuration, I could do so, but I don't think that is going to happen, not if I am the one listening to them. So, is there anything I'd do differently? Absolutely. I've already made one small change, by removing the felt over the driver. Didn't need it with these velour pads for some odd reason that I can't really explain. But there are a few other changes I'd make. The pad mounting system I made is egg-shaped, but I could have extended it a little more towards the bottom of the cup. Didn't know beforehand if the pad's vinyl flap would stretch enough, but it would have. Also, when I cut the interior of the cups on my router table, I was making blind cuts, and was very conservative on depth. I could have shaved off another 10 or 12 grams of weight from each cup. That's ok. It was a learning process, and I'll remember that if I ever make another set.

Hope this has been informative, or at least, entertaining.

Edit: Didn't take long to come to the conclusion that the velour pads weren't working all that well. Oh well, that's par for the course when experimenting. I'm back to the original pads now. I'll use the Brainwavz velours on a different headphone.

I'm thinking about modifying my R9 using carbon fiber on the external cups to make them rigid and also on the internal top cover where the drives are located, putting wires of something rigid because this cover where the drives are fixed is very soft and vibrates along with the drives.

 

[Maxx134]

Double post caused by network lag on my end.

 

[Maxx134]

I'm thinking about modifying my R9 using carbon fiber on the external cups to make them rigid

You can add clear coat paint over the stock cups, to make them more rigid as well. Yet I don't really see the cup as an issue.

All cups in general add reflections which affects the opennness. Then there is the added resonances which add the harmonics to the tone of the headphone. Both aspects can be labeled as "sounding" good or bad. "Distortion" itself s a broad term usually labeled bad, but in reality is what describes the character of the sound of the headphone. None of this is bad.

The overall results can be both good or bad, regardless of the amount of these "added" effects on the sound.

They are what sonically distinguishes the type of headphone, wether open or closed, big or small , dynamic or planar. It is all distinguished by their specific "distortion signature".

Therefore what makes a good headphone?
None of the above.
It is the frequency balance, and the resolution.

But what is resolution?
IMO from my experience, it lies in the "speed" & sensitivity of the driver, not any distortions that is inherent to it's design.

Yet as consumers, all we can do, is tailor the frequency response and use damping materials to give us an appealing sound.

In this thread, I must give props to the thread starter's great effort in customizing cups and tuning the sound.

We learn thru his experience the great key that manufacturers have been doing to get away from any cost of internal damping material usage. The "trick" of porting. Thru this method, we see we can tune the diver more effectively than any materials usage. This is usually done on the baffle plate area around the driver.

Also, From the depth of the cups, I can see they are in the "sweet zone" of cups "depth" to add tonality (harmonics) without getting noticable in slight sound reflection delays or increased resonances which can affect deeper cups.

It's nice to see such mod variants, and so the next this would be interesting to see if this driver is preferable to the bio cellulose or paper type.

I noticed so far that most of the poly-coated drivers like this one, are soft and not as stiff, except for the top Sony type drivers, which are stiff.
I don't know if this driver has a soft membrane, or a stiff one like the Sony.
I found stiffness helps with clarity of the sonic image.
Clarity is not resolution, but it desirable for cleaner and easier perception of detailing.