rhythmdevils RAAL SR-1a Modding Guide

rhythmdevils
RAAL SR-1a
Modding Guide


The contents of this mod and this post and the entirety of this thread is copyright © Whitney Dafoe 2022. It is only permissible to be here in this thread on SBAF and you do not have my permission to copy paste any part of it elsewhere. Links to this post anywhere are fine.







My brief impressions of the stock SR-1a

The Good

1. Incredibly resolving, probably the most resolving transducer i’ve ever heard, but not that far ahead of my modded LCD-R or LCD-5. Detail is mostly just presented very differently, it’s thrown at you with incredible force so detail is at the forefront, in front of the actual tone of the instrument
2. Very airy and open presentation which is quite magical, especially for acoustic music including acoustic guitar, acoustic piano and classical.

The Bad

1. The way detail is pushed to the forefront of the sound is very fatiguing for me and unnatural. I feel like I am analyzing details not listening to music. Naturally, in music, some details are louder and some are softer and buried deeper in the mix. There is a variation and levels of detail. Some are buried deeper. it’s as if the SR-1a makes all detail exactly the same loudness. I could come up with some photography analogy, there are filters or sharpeners that would do something similar to an image. All details are not supposed to be equal loudness, there is supposed to be the fundamental tone, covered with varying levels of detail, some very faint. The SR-1a detail portrayal is all the same, sort of flattened if you will, while other resolving headphones have a depth to the detail retrieval.
2. There is a feeling of pressure build up in my ears that is uncomfortable, as if the drivers are pushing huge volumes of air into my ears in an unnatural way. It hurts my brain.
3. The leading edges of notes and attacks are super sharp which is part of the reason detail is presented the way it is. But a lot of notes and instruments are way way sharper than they should be naturally. Talk about turning the sharpening ALL THE WAY UP on an image. You can kind of get into it because it makes them so resolving, but I can’t listen to most music with these headphones, its’ too unnatural. There is a natural softness to the tone of some instruments, not everything is razor f'ing sharp. The only thing that works for me is classical, solo piano and solo acoustic guitar. Everything else sounds very unnatural.
4. There is a lack of bass that makes the presentation kind of lean. I would say that most of the midrange is flat and the treble is a bit elevated (all cymbal/ treble percussive work is too loud in the mix for example), and then they start rolling off in the lower midrange and bass and lack bass extension as well. This causes a pretty thin sound that is also unnatural.
5. I hear a lot of resonance that I suspect is reflecting off the wings and around the driver itself, manifesting in the form of howling, screeching sounds on top of notes like vocals for example, which are intolerable to me.

Introduction

I thought about doing this mod commercially for a second, but it’s so easy to do, it’s much easier than any of my other mods, so I instantly wanted to just share it with the community, partly to give back for supporting my commercial mods and letting me share them with you all, and also just because it would be a bit silly to ship your SR-1a all the way to me just to do this. (I’m hoping to share mods for some orthos as well when I have the time and energy to write them up)

However, I will add this to my list of headphone mods and offer to do it on consignment for anyone for a pretty low price, probably $150-$300, but we’ll see TBD. It depends on how much work and time it consumes. Also realize that it took years and incredible amounts of time finding these exact materials, learning how to use them, and spending tons of money on literally thousands of materials that did not work as well. I have rooms full of materials that don’t work or only work for very specific things.

But anyone can do this mod, it's very easy and takes only about two hours and only that long because of cutting materials precisely. The cutting is the only part that is difficult. Applying them takes only maybe 30 minutes. It requires no special skills other than being patient and attention to detail so that the left and right side get modded equally so there’s no channel imbalance. And you don’t do something stupid.

I’ll divide it into 2 sections, the first part is super easy and literally anyone can do it to increase bass response and reduce resonance. Part 2 just further reduces resonance and is good but not necessary to see benefits.

I’ve written this sort of "for dummies" so people good with their hands will probably not need so much detail, but I wanted it to be accessible.

The Mod

After listening to them for 2 hours stock after I got them in the mail, I had an idea for how to increase their bass response using a material I’ve used for ortho damping and earpads as well many times. I went and got it and attached it, and it worked geat, the bass increased by a factor of 2 give or take, and a lot of the resonance was reduced as well. The material is rings of foam made for dry eye goggles for people with chronic dry eyes to wear at night, and get the foam wet if they want as well so their eyes are surrounded by moisture. It’s the highest quality visco-elastic foam (memory foam) available (not available to the public unfortunately, I have tried), which is then put through a special process to compress it to make it super dense. So it winds up being the densest open cell foam I’ve ever encountered and I’m guessing the densest open cell foam that exists. Meaning that sound pressure can pass through it, but with great difficulty. This makes it absorb sound incredibly well, and the foam structure does so in an even way, which many materials do not, they reflect some frequencies back, or absorb different frequencies differently. I’ve used this foam for resonance absorption in ortho damping and as earpads before, and as earpads, they are very very basy because of the density of the foam, they don’t let much bass escape.

I then sought to decrease resonance further by adding another material all over every other surface of the front of the driver and the wings. This second material is a very thin super dense adhesive backed foam that is made to weather seal cracks in doors. I get the thinnest version of it available, it comes in different widths. Like the goggle foam, it absorbs sound very well, and in an even way, not absorbing some frequencies more than others, and not reflecting anything back. If you cover a surface with this stuff, you eliminate all reflections. It’s really great. I cover the front baffle of all my Audeze mods with this material, right up to the edges of the driver. If you did this with other materials I have tried, you would muck up the sound because of the way the material absorbs sound. Surrounding the front of a driver with that computer silencing foam for example that was really popular with all the T50rp DIY'ers really deadens the sound and makes the drivers dull. Creatology foam also does not absorb sound that well, it reflects some back, creating some midrange resonance. I could go on… This material does not do anything like this.

Implementing the mod

Materials needed
Total cost is about $50

Goggle foam - LINK TO BUY







You only need 1 left and 1 right foam rings, in other words one package of the replacement goggle foam but it comes in sets of 3, so you’ll have extra in case you screw up or want to mod your friend’s SR-1a. Buy the regular size unlined version linked here. You’ll only use the outer ring and can throw the inside part away.

Resonance absorbing strips - LINK TO BUY

This isn’t the same brand I own, they stopped making the 1/16" thick version, but this looks like exactly the same material. I’ll buy some and compare. You want the 1/2" wide or 1” wide and 1/16" thick version like in this picture from the amazon page of choices. The 1” might be easier to work with than the 1/2” I have but I’ll recommend the 1/2” since that’s what I know.







You’ll have to buy 3 whole rolls of this, and won't need nearly that much but it’s cheap so it doesn’t matter. Modders will have fun with the rest of it and others can weather seal their doors! I used 1/2" and 1/4" width both, but you can just cut down the 1/2" width and just buy that. That’s what I would recommend. The 1/2" width is much easier to use to cut into the very thin strips you’ll need because your straight edge has more to hold onto and cut from.

Tools Needed

• Razor blade exacto type knife with a fresh razor blade
• Scissors
• Cutting board of some kind. I use a plastic slab that's made to cut on.
• Straight edge to cut along - I have a brass straight edge. Just make sure it’s not bent, or it won't work well as it won’t hold down the material evenlly and it will slip out in some parts, giving you uneven cuts.
• Lots of light, or a headlamp if you work like I do like a gremlin in a cave with a headlamp on

 

Instructions

i’m going to divide this into 2 parts. If you have fat fingers and can’t manage cutting or precision, or just can’t be bothered, you can get a lot of the benefit of this mod by just dong part 1. It will give you the increased bass response and a lot of resonance absorption as well, just not as much resonance absorption as part 1 and 2 together. So literally anyone can at least do part 1 of this mod.

Part 1 - Bass Retention Wall

WARNING: Be very careful when using scissors close to the driver because they are metal and can get sucked into the driver and ruin it. Approach slowly and mindfully and work slowly, and instead of using the scissors over the driver, try to come from the side of the driver so the scissors are not directly over the front of the driver. Always be aware that they could get pulled in, and be ready to prevent it. I didn’t have much problem with this, but I have worked with ortho drivers a lot. So be aware that it could easily happen. If you’re just doing part 1 of this mod, you would have to be really stupid to get the scissors sucked into the driver.

1. Start by taking the goggle foam out of the package, throw away the inner peice and keep the two rings.



2. Cut the rings in the same place. I recommend cutting both of them in the middle of the sharpest curve as shown in this picture. You want to cut them in the same place because the foam is not uniform width around the circle, and you want both sides L/R to wind up being the same. More width gives you a different sound- more bass retention.



3. Peel off the white paper to reveal the adhesive. This is very very strong adhesive because it is made to stick to silicone (I wish I knew what they were using, it’s amazing stuff). So if you just stick them on this way, if you want to remove them, the foam will tear before the adhesive will come off and you’ll have to pick at the adhesive for a loooong time. You don’t need it adhered this strong, so I recommend sticking it to a sheet or shirt or something a bunch of times until it is covered in some lint and feels less sticky.

4. Apply the foam to the outside edge of the wings, you want it to go from the top of the driver, around the outside edge of the wings, and then reach the bottom of the driver. One ring is longer than you need, so you’ll wind up cutting a bit off. Remember, you cut the circle - you want to start with the same side of that cut with both sides so that once applied to both sides, it winds up being mirror images of each other, that way despite the thickness not being equal along the strip, L/R are mirror images of each other. ie. if you were to look at the goggle foam rings next to each other aligned as goggles, you want to start with either the top part or the bottom part on both sides.

5. So start at the top of the wing right next to the driver and slowly push it onto the wing. When you’re applying it, watch the outside edge of the wings, and line up the outside edge of the foam strip with the outside edge of the wing. You can push it and angle it as necessary to make it conform to the angles of the wing, the adhesive will make it hold the same shape as the edge of the wing. Slowly move down the wing like this, making the outside edge of the goggle foam strip line up with the outside edge of the wing. Until you reach the bottom of the driver edge, then cut the foam so that it goes right up to the edge of the metal. Try not to stretch the foam while applying it, because that would make it less dense.





6. Do this on both sides, starting at the same side of the foam so the two sides are mirror images of each other.

Note: this image includes part 2



7. Now you’re done with the bass wall. This wall creates a tiny cup so there is a small cavity there that acts like a bit of an earpad (free floating, it doesn’t touch your skin or ears) and holds in some bass. But the wing is attached to the back of the driver, and these goggle foam strips are the same height as the driver, so it winds up being the same height as the driver itself and doesn’t touch your ears or behind your ears at all unless the driver does.

Part 2 - Resonance strips

1. Now you basicalliy just want to cover as much of the front of the driver and the wings as you can with the weather stripping strips. I put a full width 1/2" piece at the top of the driver, along the whole top, and a half width piece along the whole bottom.

2. Now you have to get out the razor blade knife, cutting board and straight edge.



WARNING: razor blades are incredibly sharp, so never cut towards your fingers or any part of your body. If you slip and cut yourself, the blade will cut deep, you will probably need stitches. I’m not trying to scare you, people use razor blades to do things like this all the time, but I’m just urging caution. People who work with razor blades are careful.

Put the straight edge on top of a long strip of the weather stripping foam, and move it to cover most of the foam strip so that there is only a tiny thin strip showing. You want the part that is uncovered by the straight edge to be the same width as the bars that go across the driver, as we’re going to cover the ones that go horizontally (if you’re holding the SR-1a by the headband).



We’re also goinig to cover the left and right sides of the driver, which are equal width as the beams that go across. So you’ll want two long very thin strips for each side of the both drivers (4 total) and short very thin strips for each horizontal bar crossing the driver. It’s best to try to make these all equal width and the same width as the bars across the driver. Which is hard to do, you’ll make mistakes and some will come out wider or thinner, or crooked and uneven, and you just throw those away and keep cutting thin strips until you have enough equal width to the bars on the driver to cover all the mentioned areas, as seen in this picture. (Both sides of the driver, and every horizontal cross beam)

it’s good to make them a bit longer than necessary them cut them down to just the right size on the driver. And cut them a bit too long and squish them in because they stretch when you apply them and will wind up pulling back and not being long enough. (As you can see in later pictures some of mine did)



note: I’m coming at the driver with the scissors from the side not on top the driver.



2. I also cut little squares and placed them on the wing in the middle of the spaces in the wing between the dividers. It would be great to cover the whole inside of the wing with this stuff, but the spaces between these dividers is an odd shape and it would take a lot of effort, plus I don’t think it is necessary. A square piece in the middle will absorb all the sound hitting that spot. But go to town if you want.



That’s it. You’ve made the bass wall, and you’ve covered the front of the driver and the wings with resonance absorption.





RESULTS

Impressions after the mod

There is about 2x more bass now, enough to be enjoyable with many more genres of music
Vocals are soooo much better, there is no longer any howling or screaching on top of any FR range in the spectrum. Vocals sound natural.
The whole spectrum is much smoother, lacking any shout.

Some of you I imagine are worried about loosing resolution by adding damping materials or ("soft stuff") around the driver, but the truth is that by removing resonance, you are hearing the driver in it’s most pure form. Instead of hearing the sound coming from the driver plus a bunch of reflected sound waves that do not match the original signal, you are only hearing the sound being produced by the driver.

It maintains about 95% of the openness, airiness and soundstage of the stock SR-1a and I think this reduction might even just be an illusion from removing the resonance. The resonance I believe may be creating a bit of a "room affect" enhancing the sense of soundstage a tiny bit. If there is a decrease in soundstage, openness and air, it is very small, if any though.

It maintains the super fast transients, the sharpness, and resolution, this isn’t affected at all. They are still SR-1a’s in every way, just with fewer problems and a more well rounded headphone.

Refer back to my impressions of the stock SR-1a. I still don’t like the modded version, as it only addresses my last 2 problems with the headphone and doesn’t go far enough with bass. It is better to me but it still has that sharp tone and equal-loudness-detail affect. What I’m saying is that it’s still an SR-1a. I just have issues with the driver as well as the acoustics around it.

What the mod does is increase bass response naturally (no EQ) so you’r’e not just distorting the sound. And remove resonance to vastly improve the tone of the headphones. All the things everyone loves about the SR-1a are retained. It's kind of a win win and I don’t see anyone preferring them stock over this modded version. YMMV of course. It’s all removable if you followed my instructions to reduce the stickiness of the goggle foam, and even if you didn’t you can still get it off with some picking at it.

Have fun, be careful, and enjoy!


Possible Further Experiments

I would like to try something else, but I seem to be allergic to the SR-1a’s sharp sound, because i’ve been really sick ever since listening to them, and having a hard time tolerating music for a few days afterwards. So I don’t want to listen to them again.

But I would like to try adding a second layer of goggle foam to make it taller, and see how much bass is possible to get out of them by making them more like circumaural headphones. The problem is if you did this across the whole outside of the wing, the foam would touch your ears, so you’d have to add a second layer above and below the outside of your ear where it lies under the wing. Then I would like to try adding a 3rd layer to go even further, maybe even so that the foam touches your head behind your ears making them almost circumaural except for a gap for your ears, and the top and bottom of the driver. Using this foam would be the best way to create a circumarual headphone with this driver because it absorbs resonance and is so bassy used in this way. Maybe someone could 3D print a wing add on that would increase the size of the wing so that the goggle foam could be made in 2-3 layers and go around your ears. I’d love to see how this would sound.

If anyone tries this, post your impressions and lemme know how it goes!

 

Reserved

 

I modded 4 pairs of AKG K1000 recently, Butyl rubber car damping mat helped with extending its bass response noticeably. I expect it to work well here too.

 

@rhythmdevils Just wanted to acknowledge your work on this. It'll take me some time to get around to trying it, but this is a real gift to the community.

 

I should pipe up and mention that the pair of SR1a rhythmdevils kindly modded are mine. They're new to me, purchased from a Friend here, and while I've heard the stock SR1a several times previously, I've not owned them before, nor have I heard them in my own setup. I also jumped on them thanks to the recent release of the TI-1a ribbon/amp interface, which means I can listen to the SR1a with my current headphone amps, the Cavalli Liquid Gold X and the Mjolnir 1. Alas, Alexandar from Raal doubts that my Stratus will have quite the necessary power to drive them with the new interface.

All this is to say that I'll post impressions of the modded version of the SR1a soon, and I'll also include a direct comparison of them vs. stock. I just need some time to get used to their sound and to find the best match with my amps. So far, I'm delighted, and the bass is more robust than I remember, although it's been four months since I last heard the SR1a.

 

If anyone wants to try this mod on their SR-1a for free in exchange for posting some impressions for others, I have some 10 year old goggle foam which I wouldn't' feel comfortable using on a commercial mod. But it's still in good shape, it's very high quality stuff ad the same thing I used on @Tchoupitoulas 's pair which worked great. Still feels as new.

And I have tons of the weather stripping material brand new. You would have to cut that into strips yourself though.

So I could put together like 5 or 7 mod kits and send them out for free to anyone who owns an SR-1a and is interested. It's all removable. And if you like it you could buy brand new goggle foam in case it works a bit better but I doubt there would be a difference.

Send me a pm if interested to keep this thread uncluttered. I'd just want impressions of any length, positive or negative.

Cheers.