[Bigfieroman]

A little background first; it has been a while since I have been posting regularly.

About a year I joined up when I started researching replacements for my Koss UR-20 headphones. Through my research here, I ended up with some Koss Pro 4AATs and KSC-75. I posted for a while, but eventually I went back to school and stopped using my headphones.

Now that I graduated and am in the office constantly, I realized my setup was very poor for my tastes. I am really a bass head, and I hate high frequencies. The Koss KSC-75s are too open for the office, and the Pro4AATs really lack bass. The Pengamp I have really isn't great for bass either, and my source really sucked.

So I went all out for bass. I first picked up an 4G ipod and a microshar line-out cable. I realize the ipod is not optimal, but it fully integrates with my car HU (Avic-D3) and I don't want to carry around 2 mp3 players. For an amp, I went with an XM4, and swapped out the op-amp for an OPA2228. Then I went with some AKG K81 DJs, with a nice recable and Senn HD25 pads. I liked their sound, but man, they got painful after about 1 hour. I didn't realize when I bought them that they were on-the-ear type.

Too replace them, I picked up some Beyerdynamic DT770 Pro/80 ohm. They are burning in right now, (about 30 hours so far), at a fairly aggressive volume at the recommendation of a headphone friend (claimed they don't respond well to listening-volume burn-in).

ANYway, here is my question: I have been noticing some distortion/crackling noises, especially out of the right ear. It seems to happen at fairly high frequencies, like higher vocals or violins. I isolated the amp, and I was getting it out of the headphone out and the line out. I have tried the AKG k81s and it SEEMS that they do it too, but I am not sure.

So, are ipods known to crap out at high volumes and high frequencies? Or did I blow my DT770s with excessive volume (all other frequencies, in fact most songs, never distort audibly)?

 

[GreatDane]

If you use EQ on the iPod that could be the cause...or crappy over-saturated recordings.

I've also read that if hairs get caught around the transducer inside the headphone housing, that can cause noises like you describe...I've never had that happen to my 770.

 

[Bigfieroman]

I am using the EQ on the ipod, specifically the "Bass Booster" setting, I found it gave the sound sig that my ears are happiest with; I love bass and I am sensitive to high frequencies. Most of my MP3s are fairly high quality (192+).

 

[Bigfieroman]

GreatDane,

Thank you very much for the reply; it pointed me in the right direction, and with some creative searching, I found out that this is a common problem when using the EQ and a proposed method to fixing it. I am normalizing all my MP3s to 80db to prevent clipping, this supposedly will clear up the problem. My XM4 has more than enough gain to make up for the loss of volume. I will reply with my results once I MP3Gain goes through all 2717 files...

 

[GreatDane]

You're welcome,I hope it works out for you. I recently read about that fix that you mention but I've never tried it and wouldn't have been able to give instructions. That's more work than I care to go through and I don't use EQ on my iPod because...well, it sucks.

These days I only use my 80 GB iPod via headphone out into my Eclipse head unit in my truck ( iPod line out overloads the aux. input)

In order to quench my thirst for custom EQ for my ER6/ER4, I recently bought an 8GB Cowon iAudio 7 which I randomly sync to my master mp3 folder.

I can't believe that you use bass boost for the 770. [size=x-small]([/size]

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[Bigfieroman]

Heck yeah! I use the bass boost on the XM4 as well. I even swapped over to the OPA2228 opamp, the most bass-tastic of all. Really, I don't think they have that much bass. I have a small sub box in my car, 1 12" sub with only 150w RMS in a sealed box, and it blows the DT770 away in bass. But, they still have more bass than any other headphones I have ever used, and they are more acceptable in the office than a gaggle of tower speakers...