[kickin81]

I bought two refurbed HD 439s for a little more than you did for your HD 428s. When I got mine in the mail, I left one alone as I burned in the other. After about 40 hours of burn-in, I plugged in the new set and automatically noticed how tinny the mids and highs were in comparison. The bass frequencies were short and uninspiring too. These cans really do need to be burned in to experience the full sound spectrum.
 
Next on my list is to burn them both in with equal burn in time and compare them again. One modded, the other not modded. I can't promise I'll do well to describe the differences as I'm still a noob but I'll do what I can.

 

[wje]

Quote:

I bought two refurbed HD 439s for a little more than you did for your HD 428s. When I got mine in the mail, I left one alone as I burned in the other. After about 40 hours of burn-in, I plugged in the new set and automatically noticed how tinny the mids and highs were in comparison. The bass frequencies were short and uninspiring too. These cans really do need to be burned in to experience the full sound spectrum.
 
Next on my list is to burn them both in with equal burn in time and compare them again. One modded, the other not modded. I can't promise I'll do well to describe the differences as I'm still a noob but I'll do what I can.

 
For the benefit of us all learning from the experiences shared by others such as yourself, I'm quite sure what you can provide for us will be quite valuable.
 
As to the HD-428s headphone itself, it performs very well without any expensive amplification.  With other headphones, you can spend $100 - $200 for the pair, and they might require a separate amp to get the most out of them.  So, with the 428s, people can gain in two ways be getting a better sound from the mod, and also by not having to invest in a separate amp with a bass boost option to get the most out of a pair of headphones.
 
Finally, with the metal rod component of the modification I performed, I can say with 100% certainty that the HD-428s become truly a much better fitting headphone when the ridgidity of the headphone is reinforced with the metal.  These are nearly "military grade" audiophile headphones when the metal rod is added to the headband for reinforcement. 

 

[bob439]

Quote:

-- do not open up the two front holes and tape the third one as suggested by an old old post that I read. I tried this and while I got a lot more bass, the highs were so colorful and forward that it was quite painful to listen to cymbals in music. 
-- for my second attempt, I only opened up the middle hole as how WJE suggested and left the two outer holes covered by the original mesh tape. This provided slightly less bass from my first bass mod attempt but the bass will still rock your pants. Seriously, I've never appreciated Far East Movement's "Like A G6" track before. If you want a percentage of how much bass you'll get, I'd say this mod gives about 40-50% more bass and that's not saying much. It improves the boom and does so to a good portion of the lower spectrum.
-- you must do the putty mod if you plan on opening the bass hole(s). As already stated by those who have done it, I will repeat them by saying that doing the putty mod really does tighten up the bass gained. Without this putty mod, the bass becomes really fuzzy and will leak into your mids. Your bassy music will sound really bad. I went to Walmart and picked up a pack of Loctite Adhesive tack in the office supplies section. It comes in a thin, palm-size pack that has 5 strips of the blue stuff. It sticks pretty well but only time will tell how long it will remain clinged to the surface of the driver. I used about 40% of one strip for each side as there's not enough room to apply a thick layer and I only applied as much as I felt was necessary. You probably won't want it thick anyways as it will make it very difficult to open it back up to make adjustments to your mod. The adhesive strength will hurt your fingernails. It did mine.

 Still, I find it unbelievable how well this mod does to tighten up the bass from the bass mod.
 
Edit: here's a picture of the Loctite putty.
http://www.loctiteproducts.com/img/products/big/cntct_putty.png

 
My observations ...
 
Couple of things I did differently from the above method, the Lactite putty was tough to knead and apply as desired , so I applied  1 strip each on the two drivers and tested them, bass was amazing and very tight but realized that overall sound levels dropped, cans sounded dull. And they were heavy and uncomfortable after an hour's use. They were tough to drive without an amp, sounded much better when I used with an amp though.
 
But I wanted to use HD 428s without an amp, so I re-opened them and carefully removed a thin layer of putty with a fork handle, took out almost half a strip of lactite putty from each driver, and the result was amazing, improved bass like before and much better sound levels and lighter cans. Sound better without an amp.
 
p.s. I'd suggest apply the putty liberally, then use a fork handle or plastic knife to scrape a layer off the surface of the driver to leave behind just the desired amount. And save your fingers.

 

[kickin81]

Ok so I've put in 50+ hours of burn in on both of my HD 439s running random music and 'pink noise' through them. I tell you, the differences between my unmodified set and my modified set is quite large and they're like two completely different headphones now.
 
Both sets have the pad filters removed. I believe these are there primarily to block out hair, dander, dirt, etc from entering the driver. However they also muffle the sound by a good margin (I even tried talking through one of the filters and the projection of my voice was noticeably reduced). Getting rid of the filters help to distinguish better detail in pretty much the whole audio frequency (including vocals) and improves on the soundstage.
 
Unmodified:
The HD 439 is marketed to have enhanced bass. However, I notice it doesn't produce the level of sub-bass that you would expect from a headphone marketed as such. After burning them in, the tinnyness is just about gone. What's left is a nice set of cans that plays smooth, detailed music with clear vocals and with a good soundstage. This set is a bit on the cold side and produces laid back mids and highs for its sound signature. Actually, the whole sound signature is laid back. It has decent upper bass (thumps) but completely lacks on any kind of low-end bass (rumble). The kind of bass that you get from a headset right out of the box.
 
Modified -- bass mod and blue tack mod:
The biggest improvement from these mods made was to the bass so I'll touch that first. The bass has really opened up. There's a lot more rumble you both hear and feel. It is a healthy rumble that shows on parts of songs that did not exist before. Opening up the middle bass hole made the modded Sennheisers have the ability to extend into the low frequencies and brighten them up but also seems to do a good job controlling it. I don't notice bass bleed but although still tight the bass has loosened up. It finally has a level of bass most rock and rave fans require.
 
The mids and highs has also improved. As a matter of fact, they are more pronounced and textured. It's not often that you can mod a headset to have a lot more bass and not have it hurt the mids and highs. The vocalist is now right in front and so is with the guitars and drums. It feels that it's less airy now that the sound spectrum has improved so I believe this results in a smaller soundstage but ambient instruments still remain ambient and you can tell they're in the distance. Moving forward, the headset's ability to reproduce detail has slightly increased and the clarity doesn't seem to be affected. Nothing I notice has been muddied or become harsh. Any more color would have made songs too forward and not as pleasant to listen to.
 
In summary, the mods has changed the HD 439's sound signature DRASTICALLY and I'm sure the same applies to the HD 428s or any other 400 series Sennheiser. It now plays songs with a lot more energy and with better detail however the characteristics of an airy soundstage has suffered somewhat. Still, it's so much more fun to listen to that I will be modding my other set as well and use it as my second. I don't have any experience with other cans but I'm sure it now measures up to sets that cost a lot more, and I wholeheartedly will recommend these to anyone looking for a quality all-around headset without breaking the bank.

 

[wje]

Quote:

I was totally on the fence about the HD428/HD439/SR80i/AKG240.. Demo'd the 428s at BB and was horribly turned away by the lack of punch.. came close to purchasing the AKG 240s.. but something kept holding me back from pulling that trigger.

Figure I would try the HD428s after reading so many threads about how the mod really rejuvenates this set (I just bought the refurbs $27 on eBay from VM like 3 seconds ago)

Estimated date to receive is this upcoming Monday the 28th... spending $27 and expecting some good things after mods (based on reviews) is way better than throwin out $100-200 dollars while failing expectations.
 
*fingers crossed with excitement* .. I don't even have a decent pair of cans.. so this will be my first entry level attempt as a newborn Audiophile and modder.

 
Dakmart has the HD-439 for just $44.98 + shipping.  They are an authorized Senneheiser seller of the refurbished goods the sell.  http://www.dakmart.com/Headphones/c194/index.html?osCsid=fp4enf8tpbk4bgnm2uefpk5060
 
Also, I'm not surprised at how the HD-428s that was being sold on Ebay is delayed like it is.  I recall about 3 weeks ago when I looked at the auction, I believe it said 1,000 available.  Yet, well over that number had been sold.
 
Be careful with this mod.  It can turn out to be a gateway onto other Sennheiser headphones.  I've since purchased: HD-555, HD-595, HD-600 (2 pair), and HD-650 and it's just Feb. 3rd.  Not even a full month since I created this tutorial.  

 

[Kamakahah]

How do you think your mod 428s compare to the slew of Sennheiser cans you've purchased since?

 

[Kamakahah]

Also, has anyone compared the modded 428s to the somic efi82-mt mods with 840 pads?
I plan on choosing one of the two pairs for my first modding experiment.

 

[wje]

Quote:

How do you think your mod 428s compare to the slew of Sennheiser cans you've purchased since?

 
What slew would that be?  

 
I think for the cost of the HD-428, and modifications, the performance of this headphone is outstanding.  If I had a more limited budget for my headphones, I'd easily stick with this one.  If one follows the mod all the way out to reinforcing the headband, the headphone is actually more solid than the "5" and "6" series of Sennheisers.
 
As to sound?  I tend to enjoy the "6" series quite a bit.  A great balance of sound.  However, I can easily say the "6" series is greater, but it comes with a cost, too.  So, the say the HD-600 is much better, one has to also consider that the cost is about 8 times more than that of the HD-428.
 
The "5" series tends to have a bit more upper frequency end to it.  However, I don't find it to be irritating and can really work well for certain genres of music, and tends to be a good performer with most types of music.  The "5" and "6" series are open headphones, so they'll offer a bit more of a wider sound stage.  They'll also have more of an open sound and airy sound to them, too.  The HD-428, though, really digs in and gets down to business with some serious bass that the "5" or "6" series can't compete with.  At the moment, I'm leaning more towards a balanced sound as opposed to one that really excels in the bass department.  However, I can also respect that many members here really desire a good level of bass.  For that, the HD-428 is a great performer -- again, when modified as suggested.
 
Finally, one has to realize that going up in the food chain - to the "5" and "6" series can seem like a big leap when people are obsessing on upgrading and want to put more money into their headphones.  But, I can say that while the improvements can be noticed, they also may not be as great as one might have anticipated before they've received their purchase.
 
Enjoy!

 

[Theblackbeard]

So I decided to try my first headphone mod on my pair of HD 428's that I have barely been using.  I followed the instructions posted and found the whole process easy.  I chose not to use putty or anything though.  I always enjoyed my HD 428's for their comfort so I didn't want them to weigh any more than before.  
 
I started by first piercing the middle hole completely and leaving the other two intact, then put the headphones back together to have a listen.  The result was a fairly dramatic increase in bass levels.  The bass was a little sloppy though, so I covered the open hole with clear porous medical tape and had another listen.  Covering it with said tape seemed to bring out treble and opposed to the bass that I experienced with that same hole completely pierced through.
 
Then I decided to pierce another hole all the way through.  I listened again with both holes fully pierced, wow that wasn't very good.  Fart cannon's aren't for me.  So then I tried one last configuration.  I left the middle hole uncovered, and covered the second pierced hole with the porous medical tape.  I left the third hole covered by the original material, then once again rebuilt them and had a listen.  The result really surprised me quite a bit.  Much tighter bass and without noticeably affecting the mid and high's.  I have now started enjoying these cans all over again.  
 
Quite the transformation in SQ.  Very nice.
 
Cheers,
TBB

 

[mmason]

Thanks very much for the guide.  I simply cut the tape from around the middle hole as pictured and I must say it makes the bass really rumble... I'm impressed.  I'll have to look for some putty to try the vibration dampening.

 

[Magicman74]

Quote:

Thanks very much for the guide.  I simply cut the tape from around the middle hole as pictured and I must say it makes the bass really rumble... I'm impressed.  I'll have to look for some putty to try the vibration dampening.

Nice to see ya playing around Mike

,  Personally I don't like the putty. It makes them sound too forward. 

 

[wje]

Quote:

So I decided to try my first headphone mod on my pair of HD 428's that I have barely been using.  I followed the instructions posted and found the whole process easy.  I chose not to use putty or anything though.  I always enjoyed my HD 428's for their comfort so I didn't want them to weigh any more than before.  

 
Actually, there is such a small amount of putty used, the weight will hardly be noticed.  As to making the headphone more forward, that is a bit different than my experience.  However the benefit of damping the cups with putty, was more beneficial with the bass by reducing any resonance that could be swirling around.
 
Enjoy!

 

[Theblackbeard]

Quote:

 
Actually, there is such a small amount of putty used, the weight will hardly be noticed.  As to making the headphone more forward, that is a bit different than my experience.  However the benefit of damping the cups with putty, was more beneficial with the bass by reducing any resonance that could be swirling around.
 
Enjoy!

 
I wasn't sure if the extra weight would be noticeable, so I guess I played it safe.  As to the resonance, I found that piercing a second hole and covering it with porous medical tape achieved a small reduction in the extra vibration caused by leaving the middle hole fully open.  I am quite happy with the result.  Not perfect by any means, and not as good as getting a new pair of premium cans (going to hunt for some tomorrow), but an improvement over the sound the HD 428's were providing my ears before altering them.  
 
So far, I have yet to come across anything as comfortable for gaming and movie watching.  Now, when I do either, the extra bass really makes them more enjoyable.  It isn't so much that they sounded bad before, but I did feel the HD 428's sound to be a little boring.  Like they were lacking something...a little more bass.
 
Now back to my glass of wine and that wonderful Yes album.  Digital vinyl and wine, so good!

  

 

[macm75]

Didn't want to start a new thread for a simple question...
I am considering the HD428's for my 8 year old daughter - would they fit small heads?
Thank You.
 

 

[wje]

Quote:

Didn't want to start a new thread for a simple question...
I am considering the HD428's for my 8 year old daughter - would they fit small heads?
Thank You.
 

 
In my experience, the HD-428s is a bit loose - and tends to be made of the most non-rigid plastic of the whole Sennheiser line.  I have models from the "5" and "6" series, which have a better grip / fit.  This is why in my modification instructions, I used a section of metal rod to reinforce the headband, for a tighter grip.  Up until that time, the headphone fit was a bit sloppy.