SE846 Filter mod

[435279]

I received the filters pill box directly from Shure. I noticed that the white filters had no foams as expected. The blue filters had 2 foams per filter as expected. But the black filters... one had 2 foams and the other one had only 1. Whats the correct number of foams for the black filter?

Surprisingly, the sound I enjoyed most was the black without any foam. Lots of detail and the bass was all there. White with just one foam far from the attenuator also sounded good to my ears. It sounded like a very flat EQ, perhaps what the blue should have been. But black with no foam.. has anyone here given that a listen? To me it sounded like the white, but with more bass. Im starting to think that the attenuator in the Black filter is dense enough that it kills the harsh stuff without even needing supplementary foam.

Very interesting, thank you for testing this. To be honest I've never even tried the white/black filters, just the blue with and without foam (my current choice) perhaps I will try some of the other combinations one day.

 

[unispeed]

Black filter with only 1 foam positioned in the middle of the tube. The position of the foam in the tube seems to influence just how much treble is allowed into your ears. The closer it gests to the attenuator, the brighter the sound, at least that's what my ears are telling me. With this configuration i don't feel the need to adjust the volume, even after hours of listening. I tend to raise the volume when its too little treble and lower it when the treble is too pronounced. This just sounds good to me, even after prolonged listening.

I'm interested in hearing your opinion of this if you decide to try it. What have you got to lose, you're probably not using the black filter in its stock configuration anyway. LOL

 

[csglinux]

Below are measurements for some of the mods suggested by @unispeed. I can't keep pace with the rate @unispeed is suggesting these mods But I found the time to take a look at the following:

1) Trishd mod on the white filter (using blue filter foams)
2) Trishd mod on the black filter (using black filter foams)
3) HH mod on the white filter (using blue filter foams)
4) HH mod on the blue filter (using blue filter foams)
5) HH mod on the black filter (using black filter foams)
6) Half-way mod on the black filter (using black filter foams)
7) Stock white, blue & black (just for comparison)

To clarify what all this means...

Stock filters:
White with no foam
Blue with blue filter foam at open end of filter tube
Black with black filter foam at open end of filter tube

Trishd mod:
White - all blue filter foam pushed down to the damper end of the filter tube
Blue - all blue filter foam pushed down to the damper end of the filter tube
Black - all black filter foam pushed down to the damper end of the filter tube

HH (half & half) mod inspired by @unispeed:
White - half the blue filter foam at the open end of the filter tube; the other half pushed all the way down to the damper end
Blue - half the blue filter foam at the open end of the filter tube; the other half pushed all the way down to the damper end
Black - half the black filter foam at the open end of the filter tube; the other half pushed all the way down to the damper end

Black Half-Way mod suggested by @unispeed:
All foam in the black filter pushed approximately half-way down the black filter tube.

Black No Foam Mod
Hopefully this one's obvious?

The first point of reference is my current configuration of blue/trishd mod + SpinFit Cp800 eartips. I've made most of my previous measurements with SpinFit tips, but all subsequent measurements here were made with Comply Comfort foam tips, since that's what @unispeed has been using. Some important points first. Foam vs silicone makes a difference:

Also, foam tips make a difference depending on whether you properly prepare them or not. "Preparing" a foam eartip involves squashing down the end before rolling the tip. This shortens the length of foam tube the sound waves have to travel through and limits the high-frequency roll-off. Tip on the left is un-prep'd; tip on the right is prep'd:



Here's the effect of tip prep using the blue-filter Trishd mod:

It's a significant effect. N.B. All subsequent measurements are using prep'd Comply Comfort foam tips.

Effects of mods to the white filter tube:

Effects of mods to the blue filter tube:

Effects of mods to the black filter tube:

Some points/thoughts/observations:

1) The dampers aren't the same at the bottom of each of the stock filter tubes!
2) I used the foam in the blue filters to mod the white filter, because (obviously) the white filters don't come with any foam - they only have the damper at the bottom.
3) The foam in the black filter appears to be denser than that in the blue filter and so the Trishd mod with that foam seems to have a slightly stronger effect.
4) The Trishd mod magically squeezes energy out of the mid-range and into the treble. It actually gives more treble than if the same filter tube were used without any foam at all.
5) The HH white filter mod and half-way black filter mod give a surprisingly similar effect. They both give an FR that's relatively flat.
6) @unispeed obviously has good ears - he's right that the black filter give more treble as you push the foam towards the damper/attenuator.

I continue to be impressed with what a versatile little headphone the SE846 is. Endless hours of EQing fun await you, if you're so inclined

P.S. All measurements here are raw/uncompensated using a 711-compliant coupler fed by a 0.025 Ohm output-impedance source (Chord Hugo 2).

 

[unispeed]

@csglinux Thats an astounding amount of data you've got! I'll have to carefully study all those graphs to really understand whats going on. Thank-you so much! I also learned something new with the prep of the comply tips. It was interesting to learn how much of an effect proper prep has on the treble. As a side point, when I got my black filters and did my modifications I only used one piece of foam inside each one about half-way through the tube.

Lately I've actually been listening to a new configuration but I don't expect anybody to copy/test this one because it involves modification of the foams. I started out with an empty blue filter. Then I took just 1 foam from the blues and cut it in half with a razer blade. I put one half in one filter tube and the other half in the other filter tube. Both halves are pressed against the attenuator. Then I took the other foam (uncut) and put it 3mm from the opening (Im using a tiny allen bolt and nut to adjust the depth accurately. The bolt is small enough to enter the plastic tube and the nut that is threaded on the bolt assures that the foam is pushed to the correct depth).

I would describe this as a Thrishd setup but with a stronger midrange. It sound to me like it still maintains some of the increased bass that seems to come from shoving a foam right up to the attenuator, and then the depth of the outer foam is adjusted to increase or decrease the treble. (Deeper = More Treble, Shallower = Less Treble).

Again, I don't suggest anyone tries this because then you have a cut foam, but if you order or have an extra set of blues, its definetly worth a listen. I especially love the way guitars sound when configured this way.

 

[csglinux]

Hi @unispeed, It sounds like what you did with the blue filter is almost the same as what I called the HH (half and half) mod. One curious point about the SE846 - it seems they first shipped with only a single piece of foam in the black and blue filters, but at some point, some of the filters ended up getting two pieces of foam. I had an older model SE846 with only one piece of foam per filter tube. My newer SE846 has only one piece of foam in the black tubes, but two in the blue. Go figure. ¯\_(ツ)_/¯

Anyway, I see no harm in cutting the foam if your filters have only the one piece. We each of us have to spend a bit of time to find what FR works best for us, so kudos on doing your due diligence. There are some interesting things you're trying there. It's always amazing to me how big of a difference something apparently so minor can make to the sound.

 

[unispeed]

Hi @unispeed, It sounds like what you did with the blue filter is almost the same as what I called the HH (half and half) mod. One curious point about the SE846 - it seems they first shipped with only a single piece of foam in the black and blue filters, but at some point, some of the filters ended up getting two pieces of foam. I had an older model SE846 with only one piece of foam per filter tube. My newer SE846 has only one piece of foam in the black tubes, but two in the blue. Go figure. ¯\_(ツ)_/¯

Anyway, I see no harm in cutting the foam if your filters have only the one piece. We each of us have to spend a bit of time to find what FR works best for us, so kudos on doing your due diligence. There are some interesting things you're trying there. It's always amazing to me how big of a difference something apparently so minor can make to the sound.

So when you talk about an HH blue for example, youre taking a blue filter, removing the 2 foams that are inside of it, cutting one of the foams in half, and placing one half against the attenuator and one half at the opening of the tube?... meaning, you would in effect have 1 uncut left-over foam per blue tube... Did I understand that correctly?

 

[csglinux]

So when you talk about an HH blue for example, youre taking a blue filter, removing the 2 foams that are inside of it, cutting one of the foams in half, and placing one half against the attenuator and one half at the opening of the tube?... meaning, you would in effect have 1 uncut left-over foam per blue tube... Did I understand that correctly?

I simply took the two pieces of foam that were already there (cut) in the blue filter tube and pushed one down flush to the damper and left the other near the opening. Bear in mind all this is a bit approximate, because the two pieces of foam weren't exactly equal in size (and likely won't be in anybody else's either). I'm only trying to show the general trend which is, sort of expectedly, half-way between stock and the full trishd mod.

 

[unispeed]

I simply took the two pieces of foam that were already there (cut) in the blue filter tube and pushed one down flush to the damper and left the other near the opening. Bear in mind all this is a bit approximate, because the two pieces of foam weren't exactly equal in size (and likely won't be in anybody else's either). I'm only trying to show the general trend which is, sort of expectedly, half-way between stock and the full trishd mod.

Ok, I understand now. In that regard I think my current setup will sound different. Let me explain why. What you're referring to as "half" pieces of foam are in reality the stock size that came with the tubes. In that sense then, each foam unit in the current blue filters would be seen as a half.

What I am currently doing to the blues is taking one of those units of foam and dividing it in 2 halves. This results in a filter that looks a bit like this.

=================
A [[F1]]------[[[[F2]]]]
=================

A=Attenuator
F1= 0.5 of a stock foam unit
F2= 1 stock foam unit

 

[csglinux]

Ok, I understand now. In that regard I think my current setup will sound different. Let me explain why. What you're referring to as "half" pieces of foam are in reality the stock size that came with the tubes. In that sense then, each foam unit in the current blue filters would be seen as a half.

What I am currently doing to the blues is taking one of those units of foam and dividing it in 2 halves. This results in a filter that looks a bit like this.

=================
A [[F1]]------[[[[F2]]]]
=================

A=Attenuator
F1= 0.5 of a stock foam unit
F2= 1 stock foam unit

Well, you've got an infinite number of possibilities there buddy Go wild, and see what works best for you!

 

[unispeed]

Well, you've got an infinite number of possibilities there buddy Go wild, and see what works best for you!

Thats why I like these IEMs so much. Their versatility makes an already good product that much better. Really, anybody who claims that they dont have enough (fill in the blank) for their liking has not really explored the many eq curves that can be had just by moving foams in or out just a few millimiters.

Additionally all those graphs that you've posted will give someone who doesn't want to do extensive testing a guide on modding their stock filters in a controlled and repeatable way. Thanks for all the work you've done with those.

As for me, I think I will keep rocking my "weirdly" modified blues because quite honestly, I think I may have found my sweet spot with these filters.

 

[tbritton]

For the science behind it, see this white paper by Knowles, the manufacturer of most IEM drivers:
https://www.knowles.com/docs/default-source/default-document-library/tb-14.pdf?sfvrsn=2
Note what it says on pages 2 and 3 about moving the damper (that's what those foam pieces are called) just slightly!

Terry

 

[tbritton]

This paper is written a bit more clearly. About half way down they discuss tube length and diameter and the dampers' position effects.
https://www.innerfidelity.com/content/how-balanced-armature-receiversdrivers-work

Terry

 

[EastOne]

For the science behind it, see this white paper by Knowles, the manufacturer of most IEM drivers:
https://www.knowles.com/docs/default-source/default-document-library/tb-14.pdf?sfvrsn=2
Note what it says on pages 2 and 3 about moving the damper (that's what those foam pieces are called) just slightly!

Terry

Based on the paper from Knowles, I tried flipping my dampers based on the first mod in this thread, so the damping cloth is further from my ear (ie, backwards compared to how it's pictured in the thread), based on Figure 6 on page 5 I think in the above link.

On the surface it brings out more treble clarity (I use the red 2.2kohm dampers coupled with the needle tube mod from Jackomik) and it brings the treble more in line with the brown 1k sound, while the bass still being very visceral and present compared to the brown filters.

Additionally, it's really expansive, I'm not sure if this is exacerbated from the needle mod, but while the width of soundstage isn't different (the jackomik mod makes it very very expansive anyway), it feels like the 'height' of the soundstage has increased by a significant margin.

I suspect this is from a compression coefficient of the air before the filter, where less air = less ability to compress, and reduces the amount the filter damps as mentioned earlier in the thread, and the needle mod drops this coefficient heavily allowing for a more expansive 'airy' sound. The increase in treble as a result of lack of damping possibly compounds this.

Of course it's all conjecture and I could just be wrong, I can't make any measurements of this.

Would definitely recommend trying this out, especially because it doesn't cost anything.

 

[unispeed]

Based on the paper from Knowles, I tried flipping my dampers based on the first mod in this thread, so the damping cloth is further from my ear (ie, backwards compared to how it's pictured in the thread), based on Figure 6 on page 5 I think in the above link.

On the surface it brings out more treble clarity (I use the red 2.2kohm dampers coupled with the needle tube mod from Jackomik) and it brings the treble more in line with the brown 1k sound, while the bass still being very visceral and present compared to the brown filters.

Additionally, it's really expansive, I'm not sure if this is exacerbated from the needle mod, but while the width of soundstage isn't different (the jackomik mod makes it very very expansive anyway), it feels like the 'height' of the soundstage has increased by a significant margin.

I suspect this is from a compression coefficient of the air before the filter, where less air = less ability to compress, and reduces the amount the filter damps as mentioned earlier in the thread, and the needle mod drops this coefficient heavily allowing for a more expansive 'airy' sound. The increase in treble as a result of lack of damping possibly compounds this.

Of course it's all conjecture and I could just be wrong, I can't make any measurements of this.

Would definitely recommend trying this out, especially because it doesn't cost anything.

Sometimes I wish my ears were good enough to detect things like "height" and "soundstage". My ears seem to only detect changes in EQ. It sounds like you are going the Knowles filters route. I've never tried them so I cant comment about them. I have however experimented with the stock filters and with the help of members on this forum (specifically this very thread) and their research realized that damper placement does affect the EQ curve in ways I didn't even realize. So I would agree with you that flipping the Knowles filter around probably does net a slightly different sound.

I however have opted to control the sound in stages by using a combination of foam dampers with the filter. If I was to illustrate it its like going from a single tone knob on a tube amp to a more detailed equalizer. The only compromise is loss of overall volume but the gain is control over more aspects of the EQ. I have to give credit where its due though. Somebody on these forums by the screename of Trishd stumbled across something quite amazing by accident. When rebuilding his blue filters he stuffed the foams deep against the attenuator. The side effect of this "wrong" configuration what an increase in treble and a decrease in the midrange. As @csglinux once described it to me, energy was being sucked from the midrange and infused into the highs. Now many on this forum have chosen to stick with this configuration and prefer it due to the scooped sound signature it creates.

My mod is based on this principle, Im just controlling how much of that energy is being taken from the mids and given to the highs by altering the depth of the outer foam. The reason I am starting out with a white filter is because Im using foam placement to control the EQ curve. The white filter seems to color the sound less than the blue. If you feel adventurous give this mod a shot and tell me what you think. Its completely reversible... just keep track of which dampers belong to the blue filter and which belong to the black filter as they are not the same density.

 

[unispeed]

Today while I was working on a pair of modded black filters I accidentally punctured through one of the filter cloths with the pin I was using. Of course I ordered replacements because I think the black filter has potential. But here I was with these unusable filter casings.

I thought, why don't I order some Knowles filters and put them in these tubes.. after all, I would have the benefit of the O-ring and might dodge that 8KHz shift in the frequency response. @csglinux I have a gut feel this happens because of a combination of filter placement, tube diameter, and tube material. Keeping the stock insert tube would eliminate all of these variables.

While navigating the Mouser web site I noticed that Knowles manufactures these filters in 2 diameters. In the past everyone has attempted to use the bigger diameter filter because they were trying to bypass plastic filter tube altogether. The one person on these forums that tried what I am proposing did it by disassembling the larger diameter Knowles filter, removing the cloth, reshaping it with a paper clip, and stuffing it in place of the stock cloth. Upon measuring the diameter of the stock filter cloth I noticed that the Knowles filter that is 1.78mm in diameter would snugly drop right into the Shure filter tube (without modification, metal barrel and all). This would allow for 3 things.

1. Placement of a Knowles filter very close to the BA.
   • Since the filter is placed so close to the BA it should allow for the usage of a slightly denser "Green" filter (BF-3038-000) while achieving the same level of attenuation of say a "Brown" filter placed further away.
   • Attenuation increases as the acoustic resistance moves away from the BA.
   • Additionally as the filter moves away from the BA it affects a greater part of the FR curve. By having it closer to the BA it should tame the peaks without affecting the rest of the FR curve.
2. A test that directly compares the Knowles filter to the stock Shure filters.
   • Having the Knowles filters in a plastic tube should help with avoiding frequencies cancelling each other out. In a metal tube I have a feeling that some of the higher frequencies are sympathetically resonating with the metal itself effectively cancelling each other out.
   • I've built a couple of electric guitars and ran into this problem, especially when using very hard woods like bubinga and ebony. In the guitar world they call this a dead spot... the note starts out extremely loud and decays unnaturally fast because the neck of the guitar is vibrating sympathetically at that exact pitch. In the violin world, because the vibration continues, this is known as a wolf tone.
   • I have a gut feel that something very similar is happening here especially since the dropoff is happening in the high frequencies.
3. Retain the ability to fine tune the high frequencies with the foam inserts.... or potentially get rid of the foam altogether and install a second Knowles Gray filter (very low acoustic resistance) placed near the end of the tube.

Anyway, that's the plan.. lol, now I am waiting for all the parts to come in middle of next week. I gotta find some green paint...If this experiment works out it should be known as the "Green Filter"