INTRO

The Oppo PM-3 pads and headband are notorious for flaking off even without use. The bonded leather is of terrible quality. I do not have a good handle on how to replace the headband or what to replace it with, so I just bought a zipper neoprene style headband to cover that. The following is a how-to guide and short review of the replacement pads. I performed this mod a year ago during the pandemic and the YDYBZB pads still seem to be holding up well.

None of my links earn me or Audioreviews.org an affiliate kickback. They are merely links to the products I used.

SUGGESTED TOOLS

• Plastic pry tool (or a butter knife) Plastic is preferred since it is softer and will no mark up the headphones. The butter knife should work too, but no guarantees it will not leave marks on the headphones.
• Small flat bladed screw driver or similar used to scrape and pry glue off or separate the pad.

REPLACEMENT PARTS

• Headband LTYIVABHTTW ($11)
• Brainwaves Sony Replacement Leather Pads–I did not think these fit the original aesthetic but some people use them ($29)-Option 1 (OK)
• YDYBZB Sheepskin leather replacement pads for Oppo PM-1,2,3 ($22)-Option 2 (Better)

PART ONE-PAD BRACKET REMOVAL

First step is to detach the pad retainer bracket off the Oppo PM-3 headphones. There are 6 clips that hold it onto the headphones. Using a blunt plastic tool (preferred as it it should not leave any marks) or a butter knife, carefully insert where the pad meets silver portion of the headphones between the clip sections so as not to break off any clips. Some of the other pictures show where the clips are located.

You can either use a prying lever motion, or a twisting method. I used a twisting motion with the blunt pry tool so that it un-clips without gouging or breaking clips.

PART TWO – PAD REMOVAL

Once the bracket it is off, there are two steps to remove the pads without destruction. If you don’t care then of course cutting and ripping off is an option. I prefer not to add to the destruction and I could technically re-use the pads later for comparison sake.

Using a small flat bladed screw driver, scrape or lift the pad edge that is glued to the backside of the retaining bracket. Slowly work your way around the edge of the pad until fully unglued.

Next, using the same blunt pry tool or butter knife, slide it on the inside of the pad between the filter and bracket and work it around the edge of the bracket to release the ear pad filter from the bracket. It is lightly glued to the bracket in six places as seen below in the photo.

PART THREE – PAD ATTACHMENT

Now onto the next step of attaching the new pads. I choose to use the YDYBZB brand pads because they were closer to the original size however still thicker (~1/16″ or 1.5mm) and felt more premium than the Brainwaves ones in both padding and texture.

The Brainwaves also had a wrinkled appearance that is found along the stitching similar to the Sony’s, but not the Oppo PM-3. The filter of the YDYBZB appears thicker but still relatively close to the original while the Brainwaves was easily thicker having two layers of cloth plus foam. I figured it would not alter the sound too much using the YDYBZB branded pads.

Slowly stretch the lip of the pad over the backside of the bracket. You might need to use the blunt pry tool to aid in stretching it over and use it to rotate around the bracket stretching it out and getting it over the edge. No need to re-glue it in my opinion.

Once it is in position, all that is left is to reattach the pad bracket back onto the head phones. It can be a bit tricky but I recommend slipping the top clips in first, then press firmly on the opposite bottom side to snap it back in to the two bottom clips.

Once those two clips are attached, press firmly along the left and right side edges working your way around to re-attach the remaining 2 side clips with a satisfyingly snapping sound.

SOUND CONCLUSION

So does it change the sound of the Oppo PM-3? Perhaps in a minor way because they are obviously thicker. There is less midrange enhancement, a little minor loss in bass punch and some upper treble softening. They sound a bit more open now, less closed in.

The advantage is that you should not feel the rim of the driver touching your ear for better comfort and of course no more leather flaking onto your ear. The YDYBZB pads are an excellent option for renewing the degraded Oppo PM-3 pads.

Contact us!

DISCLAIMER

Our generic standard disclaimer.

The post Oppo PM-3 YDYBZB Pad Replacement Guide appeared first on Music For The Masses.

The 29 GBP CNC Copper Mass Loading Mod DIY Kit By Custom Cans allows for an easy Mod of the Sennheiser HD 600 series headphones that improves their notoriously limp bass response.

With an addendum by Biodegraded.

Introduction

The Sennheiser HD 600 and HD 650 have been standard staples with audiophiles since 1997 and 2004, respectively. I own a pair of the HD 600, the leaner sounding model of the two that is preferred by many over the thicker sounding HD 650.

The HD 600 has been popular because of its midrange delivering natural, organic, and intimate vocals – not to forget its well extended treble. But its bass is superseded by speedier and more articulate headphone models. A HD 600 series mod to improve the bass quantity was long overdue.

Custom Cans are a British company that specialize in headphone modifications.

Purpose of Mod

Straight forward: to improve bass response by adding detail and sub-bass quantity – and keep the quality of midrange and treble. Vary the low end level according to your personal preference by selecting from four different tuning foams.

Physicals

Two kits exist, the “regular” 29 GBP copper version for HD 580, HD 600, and HD 650, which is used here. A 35 GBP “nickel-plated” copper version is optimized for the HD 6XX issued by drop.com.

In the bag are the two copper weights, these stickies, and four pairs of different tuning foams. I did not have to use the stickies as the copper weights stuck firmly to the ear of the driver without.

The Modding Process

In order to apply the mod, you have to partially take the headphone apart. Disassembly and reassembly of the Sennheiser HD 600 series is easy as well documented in videos such as this one.

For disassembly, we remove…

1. cable from earcups
2. earcups from headphone
3. grille from earcup to expose rear of driver
4. black stock foams from rear driver

We then add…

1. copper weight to back of driver
2. tuning foam of choice into the hole of copper weight

..

Now we re-assemble the headphone by

1. clicking the grilled back on the driver
2. re-attaching the earcup to the headphone
3. plugging the cable back in

Too fast? Just watch this video:

Result

I settled for the bassiest “bored” foam (sample A in the image above). The sonic result of my efforts is a more detailed bass and a bit more sub-bass…and some interesting optics. Midrange and treble remain unaffected. Biodegraded measured the frequency responses of his HD 6XX with the different foam inserts, which yield different frequency responses below 1 kHz.

For the unlikely case, you don’t like the result and would like to reverse the mod you may have to develop some patience to get the black foams back into place. The rest is easy.

If you don’t dare to remove these black stock foams, Custom Cans recommend just plugging the copper weight on top of them. This yielded zero sonic difference to my ears (I A/B-ed by sticking and removing the weight on the fly while playing music).

Concluding Remarks

The CNC Copper Mass Loading DIY Kit By Custom Cans improves the low end response of the Sennheiser HD 600 series. If you know what you are doing, the mod is performed within 5 minutes. If you don’t know what you are doing, some easily comprehensible instructions videos will help.

If you are not a modder and lack self confidence, talent, and have two left hands, you are like me. Rest assured, you cannot screw this one up.

I like the result of this mod and will keep the kit on my HD 600s for good. Try it, too, if you are not 100% satisfied with the bass of your HD 650 or HD 600.

Until next time…keep on listening!

Addendum: Some Amateur Measurements and Musings

By Biodegraded

Intrigued by mentions on internet forums, I bought this kit to try with my 2017 (Ireland) HD6XX. Like Jürgen I noticed increased bass extension and mid-bass quality, and also a bit more smoothness in the texture of upper mids and highs.

As shown by the frequency-response measurements above, mid-bass level can differ by more than 5 dB depending on which foam plug is used (my home-made flat-plate coupler unfortunately rolls off below ~70 Hz so doesn’t show relative differences in the lower bass very well). 

I was curious what might be the reason for the perceived increased bass tautness and smoother mid/treble texture. To investigate distortion in the bass, I made measurements for different mod configurations with SPL for each being 96 dB @ 100 Hz (a convenient mid-bass reference) rather than leaving them independent as in the graph above.

Comparing distortion measurements (behind the spoiler below) it’s possible to see changes particularly in how the 3^rd harmonic behaves. Ignore the big spikes in the bass, they’re because of electrical noise nearby in my building: my measurement space is right on top of the main transformer, so there’s hum at 60 Hz and multiples which the measurement program assumes is distortion – meaning 60 Hz hum appears as a spike at 30 Hz in the 2^nd harmonic, at 20 Hz in the 3^rd harmonic, and so on.

This is easily visually removed, though – let your eye follow the curves’ baselines and note how with more/denser foam, H3 is higher in the bass & lower mids compared to the other harmonics.

Distortion Measurements

Stock configuration, for reference:

[L distortion stock pic]

Copper ring only, no foam:

[L distortion Cu B pic]

Bored foam:

[L distortion Cu 5 B pic]

‘3’ foam:

[L distortion Cu 3 B pic]

Yellow foam:

[L distortion Cu 2 B pic]

Blue (densest) foam:

[L distortion Cu 1 B pic]

[collapse]

Overlaying just the third harmonics from each measurement, you can see how they vary in the bass when SPL is similar there (same colour scheme as in the FR graph):

[L H3 overlays B pic]

Notice between about 40 & 200 Hz how the tan and green curves (stock and ‘3’ foam, respectively) are about the same but purple and blue (no foam, bored foam) are lower and orange (yellow foam) higher; and the red curve (blue, densest foam) is considerably higher from the bass up to about 400 Hz.

Also, when measured at the same SPL in mids & highs (for brevity not shown here), the stock H3 curve (tan) is up to ~5 dB higher than the rest above ~500 Hz. The curves represent the levels of the 3^rd harmonic at the excitation frequency, so would manifest at ~120~600 (mid-bass to lower mids) and >~1500 Hz (upper mids & higher), respectively. 

If these measurements reflect reality (have to admit they’re pretty noisy), they indicate that adding the copper ring slightly reduces 3rd harmonic distortion in the upper mids & treble and that more/denser foam plugs markedly increases it in the bass.

The curves are all below -45 dB down from the signal level (horizontal line at 0 dB), so whether a few dB of difference down there would be audible might be argued; but the ear is sensitive to distortion, and the measured differences might cause or correlate with some other effect to generate the perception of more textured, better quality bass (don’t know about the blue foam – as the FR shows, bass is kind of absent with that one) and smoother upper mids & treble.

Regardless, I enjoy the subjective effects. My favorite configurations are the bored foam and the ‘3’ foam, with ‘3’ seeming tonally the most balanced but bored seeming timbrally the most correct across the range (and sometimes I don’t mind a bit of extra bass). Like Jürgen, I’ll be leaving this mod installed.

The post Sennheiser HD 600 Series Mod – A Practical Evaluation Of The CNC Copper Mass Loading DIY Kit By Custom Cans appeared first on Music For The Masses.

The article shows how to customize the sound of your iems by changing the frequency response – without equalization – and in a non-destructive way. That is, the modification is quickly reversible. The results of this earphone modding may vary but you will frequently enjoy an earphone more when modified than right out of the box.

Introduction: Why reversible Earphone modding?

Reversible earphone modding (“modifying”), mainly performed with micropore tape, aims to balance an earphone’s sound to better fit one’s personal tonal preferences. Those audioreviews.org authors who are also subscribing to the “Super Best Audio Friends” Forum, have always been keen on the technique.

In the following, I will summarize the basic principles and some simple tricks & tips in an easy cookbook style to assist you in getting the best out of your earphones. You then can dig deeper into some case studies provided.

Reversible meaning that, after modding, the iems can be easily brought back to their initial stage…no holes poked, nothig ripped off etc. That’s favourable if you want to sell them later…

Modding is required then some iems don’t sound right for some listeners out of the box. They may be too bright (“shouty”) or the may have too much/not enough bass. In some cases, a different cable of different eartips help, but our method is cheaper – and it can be applied on top of all others. It changes the frequency spectrum without equalization.

The idea of “reversible modding” was initiated and pioneered by SBAF/Head-Fier James444. We reproduced his wisdom with his permission on our blog, previously, whilst applying and refining it ourselves over time.

Typically, a sensitive listener wishes to reduce unwanted peaks in the upper midrange (2-4 kHz harshness and hardness area) and treble (e.g. 7-10 kHz sibilance area). And he/she also wants to attenuate an overly inflated bass, particularly slowly decaying mid-bass humps. In short, if the frequency response curve is a U or V with its lowest point in the lower midrange (let’s say at 1 kHz), this shape should open up towards a horizontal line in the eyes of an “audiophile”.

Dynamic-driver (DD) earphones, because of their comparatively simple design, are easier to modify than balanced armature (BA) multi-drivers or hybrids.

Our Success Stories

Our authors have tamed the upper midrange by micropore mod in the following iems – and included the process and results in their respective writeups (each of which gives you insights in the particular modding process) – but I recommend finishing this article first before dipping into the particulars:

• Blon A8 Prometheus
• Blon BL-05 MK1
• Brainwavz Delta
• ddHifi Janus2
• KBEAR Diamond
• KBEAR TRI3
• KBEAR KB04
• KZ EDX
• LETSHOUER S12
• Moondrop Kato
• Moondrop SSR
• Moondrop Starfield
• NF Audio NM2+
• NiceHCK M5
• NiceHKC NX7
• NiceHCK NX7 Pro
• Pioneer CH3
• Rose Technics QT-9 MK2S
• Shanling ME80
• Shozy Form 1.1
• Tin Hifi T2 Evo
• TRN BA8
• TRN VX
• Unique Melody 3DT
• Urbanfun YBF-ISS014

Materials needed

You will find most of these items in your household. The biggest hurdle may be finding 3M micropore tape. Have a look at your local drug mart or health supplies store (e.g try here if you live in Calgary).

1. 3M micropore tape (Johnson & Johnson micropore tape may be too thick; you can also try Transpore tape)
2. Electrical tape or Scotch tape (Tesa Film for Germans)
3. Alcohol swabs (only in rare cases; 2-ply because it is the thinnest)
4. Thin wire (create it from a twist tie)
5. Needle
6. Scissors

One IEM, two Vents: the physical Principles

Typically (but not always), an iem has two vents, one in the front and one in the back. Here the Tinaudio T2 as an example.

Head-Fier James444 explains the functionality of the vents (original Head-Fi post):

Front Vent: making it smaller increases bass. Explanation: the front-mod adds a tiny amount of front leakage which avoids over-pressurization in the ear canal and reduces bass quantity. Attenuation is a bit stronger in deep bass than in mid/upper bass, resulting in a bass-lighter, but slightly more mid-bassy signature. Because of the leakage, isolation is slightly reduced.

Back vent: adding air increases bass; decreasing back vent diameter makes bass roll off. Reducing the air flow through the rear vent by taping it reduces bass (cover up and poke). Explanation: the back-mod restricts airflow through the back vent, resulting mainly in mid/upper bass attenuation. Deep bass remains unchanged and strong. Due to partial blocking of the back vent, isolation is slightly increased.

Both vents: the combination of front and back-mod yields the largest amount of bass attenuation and results in a significantly more balanced signature than stock.

Reducing and increasing Upper Midrange/Treble

Attenuating Upper Midrange/Treble

Is your earphone shouty? This mod can affect the frequency range between 5 and 15 kHz, depending on earphone.

This is done by adding micropore tape onto the nozzle:

1. Cover 80-90% of the screen with a single strip of micropore tape or use two thinner strips and tape over in a cross-like manner. this should do the job in most of of cases.
2. If this does not work perfectly well, try this: cover the nozzle 100%, then take a needle and poke a hole in the middle and four by the edges.If this still does not do the job in rare cases…
3. You can also try covering ca. 80-90% with 2.5 mm square of 3M micropore tape. This resulted resulted in 2-3 dB decrease in the upper midrange of the TRN VX.

Downside: if nozzle is covered too much, micropore can slow down the bass and make it “boomy” and/or compromise dynamics and soundstage in some earphones.

Example on the right: 95% of screen taped over with 3M micropore tape removed an evil 6-7 kHz “sibilance” peak in a Knowledge Zenith ED3.

Increasing Upper Midrange/Treble

Since the human ear hears the whole frequency spectrum in context, you increase perceived upper midrange/treble by reducing bass. See below how this is done.

Reducing and increasing Bass

Attenuating Bass with Micropore Tape

This is a twofold process and involves a bit of juggling between the two. Measuring comes in handy for double checking the results.

1. Taping off the back vent. If bass is too weak now, poke a hole into the tape to dose bass quantity. As long the hole in the tape is smaller than the original vent opening, the bass will be removed.
2. Creating an air-vent (or aid duct) in the front between tip and nozzle: this easy process is described over there. If you prefer a quickie, follow these pictures…

The combination of back-mod and front mod yields the largest amount of bass attenuation and results in a significantly more balanced signature than stock. If there is no back vent, one can obviously only do the air ducting. And that’s how it goes:

Unfortunately, you will never be able to speed up the bass, that is making it less muddy…but, of course, the muddiness will appear less irritating with reduced bass quantity after modding.

Below an example of a successful mod.

Attenuating Bass with the “Gummiringerl” (=Elastics) Method

(German, Viennese slang: “Gummiringerl”…little rubber ring, elastic; name coined and method suggested by SBAF/Head-Fier James444). 

The air-vent mod can also be performed with rubber string/elastic/any other string: pull through between tip and nozzle, then cut the ends off. You can try string of varying thickness. The downside is lack of flexibility in fine tuning, but you don’t have to worry about channel balance and it probably lasts longer. And it is faster and easier.

Increasing Bass with Micropore Tape

Tape off front vent for maximum effect. If you would like to scale it down, poke a small hole. The bigger the hole, the lesser the bass. Measure channel balance after each step, or do it sonically using a sine wave (Online Tone Generator).

Example: The Tinaudio T2s’ bass can be maximized by taping the front vent over. The bass quantity can be scaled back by poking a hole into the tape.

How to add Bass Extension

That’s hit and miss and varies from earphone to earphone. The idea is to reduce the air flow in the back vent. It is a byproduct of reducing bass by reducing the size of the back vent by taping and poking as described above.

Modding Limitations – That awful 3 kHz Peak

3 kHz peaks may introduce unpleasant hardness and fatigue, but they effectively cannot be safely removed with a reversible mod. Some drivers may respond to micropore tape on the nozzle: it is therefore worth a try to either cover the nozzle grille with 80-90% of micropore tape or remove the screen with a needle, tape completely over with micropore tape and poke a hole near the edge…as described in the treble section.

Other published Mods

Successful mods of single dynamic-driver earphones performed and described by James444:

Alpex HSE-A2000 —  balancing reduction of bass and treble

JVC FD01 with DIY filters — dampening with swabs

JVC HA-FX850 — with great explanations of the physics

Pioneer CH3 — treble reduction only

Kopiokaya explains his mods of the following earphones in great detail:

TRN VX — shoutiness reduced

KBEAR Diamond — bass attenuated

Concluding Remarks

The methods I have summarized in this article may help you getting over your dissatisfaction with a recent purchase – by easy, inexpensive means. In the future, just read as many evaluations of an iem as possible to form the most complete picture.

And please, never – NEVER – fall for any YouTube hypsters/salesmen/influencers and order pricey iems on spec. They mostly want your money. We don’t.

Although this article is quite comprehensive, the relevant chapters can be easily selected and accessed from the “Table of Contents” above. All of these methods are easy and can be performed by people with two left hands. I am the best example of that.

Until next time…keep on listening!

Contact us!

Disclaimer

I thank James444 and Kopiokaya for their insights and cooperation. James444’s wisdom is reproduced here with his permission.

Our generic standard disclaimer.

The post The Principles Of Reversible Earphone Modding – Removing Shoutiness and Bass Boom… appeared first on Music For The Masses.