[ScottFree]

  The other day I turned up the bass on my IE8 to level 2 and my head exploded. 
 
That is all

 
I assume it looked like this
 

 

[EagleWings]

  Yeah I didn't think about that, maybe your tape was thinner, less glue on it so it let some air pass. But for me it was exactly the same from closed bass knob to fully opened, once I taped it.
 

 
Yeah. I used a paper tape and after a couple of times opening and closing, the glue could have loosened up. @castleofargh, if it's not too much to ask, when you are doing the experiment, could you please use a paper based tape if you have it readily available?
 
Quote:

 
Also there isn't any logic (any logic I can see, I don't say you lie or something) in increasing sub bass with opening port and reducing mid bass by closing it with tape. It's the bass that gets altered all together. 

 
It is true that opening the bass port increases the overall bass response (and not just sub-bass). But when you look at castleofargh's FR graph (to which he stated his disclaimer), and compare the IE80 Min Bass curve and the IE80 Max Bass curve, you will see that the sub-bass increased by 10bD while the mid-bass increased only by 3-4dB. 
 
And when you compare the IE80 Min Bass curve and the IE80 Tape Mod curve, you will notice that the tape-mod, tamed down the mid-bass by 3-4dB while it increased the sub-bass by 7dB. So I decided to super impose these curves to get clean sub-bass by doing a tape-mod with open bass port. I know real world physics doesn't work like 2+2=4. But even if it resulted in 2+2=3 then it is an increase.
 
 

 

 
 You may have sense of better sub bass because midrange sounds clearer due to less bass, but it really does have less bass overall (both sub and mid).
 

 
You are right about this and I don't deny it. But if the enhanced sub-bass was only a human ear perception, then the SPL meter shouldn't have picked up the increase in dB in the sub-bass region in the tape-mod. 
 

 
Bass port is supposed to alter sub bass, but since it's all connected (1 driver, can't separate frequencies) and IE80 already has problems with mid bass it also increases mid bass too. I don't see how opening port a bit can increase sub bass and closing it up with tape reduce mid bass. It's the same port that works the same way. 
 

 
Well, although sub-bass and mid-bass are bass frequencies, they are of different wavelengths, so won't their harmonic properties vary in a given vibrating space? (Edit: Actually this is an honest question and not me making a point)
 

 
I don't want to sound like I'm flaming or something, you know what you hear I guess, but it really makes no sense to me at all, which extensive listening I've done has proven to me even tho it didn't need proving.
 

 
That is alright. For all I know, my hypothesis could be false. And for what it's worth, I just wanted to speak out what I observed and would like to see if my observation stands good or not. Isn't that one of the reasons why we have these forums. 

 
 
I do appreciate you trying the experiment and pitching in your thoughts!!

 

[159650]

   
I assume it looked like this
 
 

Hahahaha! Like strapping C4s to my head. IE8 are cray cray. But I love them!

 

[castleofargh]

ok siddhartha talked, "I saw the sign, and it opened up my eyes I saw the sign". (wrong quote?

)
 
in 3 words, I was wrong!
 
in more words + graphs:
 
I used another tip to show how much the trebles could be impacted. I believe it's one I got from the re400 but I'm not100% confident, I have a lot of tips.

B stands for bass setting.
the one scientifically labeled "crap tape" is the thinnest thing I could find, if one can vibrate with the driver this is it. an I put it on and off of my table a few times to make it a little dirty and less adhesive. sorry I didn't find paper based tape. but ultimately we could go with all kind of tapes or even just put some fabric that wouldn't close the vent but dampen it more or less. at that point it's all variations of the same thing.
oh and "strong tape" is the aluminum stuff I use, it's pretty thick and very adhesive so it's closer to something solid sealing the vent perfectly.
 
obviously you notice that I was wrong and siddhartha was right, the bass setting still has an impact after being taped.
 
here is compared to no no tape so that you can estimate the changes from adding tape.

 
 
doesn't change my own use, as what I was measuring is what I was using, but I'm glad you planted the seed of doubt in my head. I learned something today.
 
 
now don't ask me why it behaves like it does, I don't have a clue. maybe the bass setting changes the air volume inside the IEM? maybe something there is a gremlin inside? I really have no idea. but the behavior seems steady so I doubt Senn used gremlins.
I hope apart from self shaming, it can help a little. ^_^

 

[EagleWings]

  ok siddhartha talked, "I saw the sign, and it opened up my eyes I saw the sign". (wrong quote?

)
 

 
@castleofargh, thank you very much for doing this for us. If anything, it was in fact your FR graph that led us to this new finding.
 
I hope the experiment did not ruin an entire evening of yours 

..

 

[castleofargh]

it was an early morning job ^_^. I got super lucky finding a tip that fits the measuring enclosure for the mic with a fixed insertion limit while getting a good seal. so I could remove the IEM, change stuff, and put it back pretty much at the exact same place without struggle. 
so it actually went exceptionally well and was fast. a nice surprise. and TBH, if the result had been me being right, I might have been frustrated for wasting my time. but it wasn't a waste of time at all, so I'm disturbingly satisfied that I was wrong 

 

[Rocket786]

   
Yes, the current IE80's come with that verification system. Amazon is actually an authorized Sennheiser dealer. But when other sellers bring in their stock of products to the Amazon warehouse, chances are, if one of those seller's stock had fakes, it might get mixed with Amazon's stock of the product. To be on the safe side, you could buy from SonicElectronix.com or BHphotovideo.com. 

Thanks for the info!  I see that the headphones are in stock at BHphotovideo.com and they're the same price as Amazon.  I'd prefer to order from Amazon because their customer service is ace if anything goes wrong and I'd get the set this week.  If the headphones come with the Sennheiser authentication system, then I don't see any harm in ordering from Amazon as I should be able to verify if they're the real deal or not and return if they are not.  Is it still better to order from BHphotovideo.com?  If so, I'll bite and wait the extra time for the headphones to come in from them.

 

[Tail]

I must say I'm very surprised of the results, especially because I didn't hear a difference with bass knob on min or on max when I used the tape, guess it was I who was under the placebo effect after all.
Still I cannot see logical explanation to this but I'll try it again now, now when I expect to hear the difference maybe I will. 

 

[EagleWings]

  Thanks for the info!  I see that the headphones are in stock at BHphotovideo.com and they're the same price as Amazon.  I'd prefer to order from Amazon because their customer service is ace if anything goes wrong and I'd get the set this week.  If the headphones come with the Sennheiser authentication system, then I don't see any harm in ordering from Amazon as I should be able to verify if they're the real deal or not and return if they are not.  Is it still better to order from BHphotovideo.com?  If so, I'll bite and wait the extra time for the headphones to come in from them.

 
It takes 2 - 4 business days to receive your item depending on where you live if you ordered from BHphoto and I believe they are located in NY. These days, most of the retailers have good enough customer support with 30 day return policy and no restocking fee. Regardless, it's hard to beat amazon's customer service.
 
But you could use Tax as a deciding factor. Amazon collects tax for certain states. And if you are in one of those states, you could save yourself some $$ if you buy from a retailer who doesn't charge tax. And if tax is not a big issue, you could just walk into a nearby BestBuy and get it without the wait (provided they do have it in stock).

 

[chawya22]

  Thanks for the info!  I see that the headphones are in stock at BHphotovideo.com and they're the same price as Amazon.  I'd prefer to order from Amazon because their customer service is ace if anything goes wrong and I'd get the set this week.  If the headphones come with the Sennheiser authentication system, then I don't see any harm in ordering from Amazon as I should be able to verify if they're the real deal or not and return if they are not.  Is it still better to order from BHphotovideo.com?  If so, I'll bite and wait the extra time for the headphones to come in from them.

I order everything from B&H. No Tax, Free Expedited shipping and the item usually ships the same day. I've also had to deal with their customer service and, IMO, that is also excellent.

 

[Rocket786]

   
It takes 2 - 4 business days to receive your item depending on where you live if you ordered from BHphoto and I believe they are located in NY. These days, most of the retailers have good enough customer support with 30 day return policy and no restocking fee. Regardless, it's hard to beat amazon's customer service.
 
But you could use Tax as a deciding factor. Amazon collects tax for certain states. And if you are in one of those states, you could save yourself some $$ if you buy from a retailer who doesn't charge tax. And if tax is not a big issue, you could just walk into a nearby BestBuy and get it without the wait (provided they do have it in stock).

Well hell, I was just about to order from BHphoto when I checked this thread this morning, and then just made a quick check on Amazon for the headphones, and lo and behold, they had dropped down to $229 from $308 yesterday!  What a great surprise!  I placed the order from them as even with tax, it was quite cheaper than BHphoto.  I made sure that it is sold by Amazon.com LLC, and it is.  I should be able to return if they don't check out via the Sennheiser authentication system.  I appreciate your help, and glad I waited a day to order the headphones!

 

[EagleWings]

  Well hell, I was just about to order from BHphoto when I checked this thread this morning, and then just made a quick check on Amazon for the headphones, and lo and behold, they had dropped down to $229 from $308 yesterday!  What a great surprise!  I placed the order from them as even with tax, it was quite cheaper than BHphoto.  I made sure that it is sold by Amazon.com LLC, and it is.  I should be able to return if they don't check out via the Sennheiser authentication system.  I appreciate your help, and glad I waited a day to order the headphones!

 
Lucky fela!!

 

[chawya22]

  Well hell, I was just about to order from BHphoto when I checked this thread this morning, and then just made a quick check on Amazon for the headphones, and lo and behold, they had dropped down to $229 from $308 yesterday!  What a great surprise!  I placed the order from them as even with tax, it was quite cheaper than BHphoto.  I made sure that it is sold by Amazon.com LLC, and it is.  I should be able to return if they don't check out via the Sennheiser authentication system.  I appreciate your help, and glad I waited a day to order the headphones!

Luck was with you. Enjoy

 

[james444]

   and TBH, if the result had been me being right, I might have been frustrated for wasting my time. but it wasn't a waste of time at all, so I'm disturbingly satisfied that I was wrong 

 
now don't ask me why it behaves like it does, I don't have a clue. maybe the bass setting changes the air volume inside the IEM? maybe something there is a gremlin inside? I really have no idea. but the behavior seems steady so I doubt Senn used gremlins.
I hope apart from self shaming, it can help a little. ^_^

 
Well, let me happily join you in having been wrong, even though I rightly guessed that vishnusiddharth's observations may have some merit.
Alas, I did guess right for the wrong reasons...

In short, your measurements prompted me to take another look at the construction of the IE8/80. Like pretty much everyone else, I assumed the bass dial was a rear vent, since it's located at the backside of the housing. (That much for the power of expectation bias lol However, these pics, that have been out there since the IE8 hit the market in 2009, show clearly that this assumption is wrong and that the bass dial is in fact an adjustable front vent:
 


 
So, basically, in turning the bass screw from 'max' to 'min', you gradually open up an air passage between the front and rear side of the driver, which leads to acoustic short-circuiting and a drop in bass level. And because of that, the tape mod's effect is only loosely related to the bass dial, since it only seals off the rear chamber and has next to no influence on the internal airflow between the front and rear side of the driver.
 
Bottom line, thanks to @vishnusiddharth's fine ears and @castleofargh's dedication to unearthing the truth via measurements, a long-standing misconception of the IE8/80's bass dial has finally been debunked. (... and btw, you guys at Sennheiser may stop laughing yourselves silly about us wannabe-modders now.

)

 

[EagleWings]

 
So, basically, in turning the bass screw from 'max' to 'min', you gradually open up an air passage between the front and rear side of the driver, which leads to acoustic short-circuiting and a drop in bass level. And because of that, the tape mod's effect is only loosely related to the bass dial, since it only seals off the rear chamber and has next to no influence on the internal airflow between the front and rear side of the driver.

 
Thanks for sharing this..