My Massdrop username is HelloFoobar. I really want to see some Stax on massdrop! I know there were drops for 3170 and 4170 but that was so long ago.

Which provides better noise isolation, Etymotic with stock tips or custom IEM?

I use Linux and DeaDBeef player. There is an option in DeaDBeef that convert 16 bit files to 24 bit. Should I enable that? Does converting 16 bit files to 24 bit really help when digitally reducing volume?

Is reducing volume in player the only way to deal with this problem? I don't think there are many headphones that are quieter than 250 ohm DT 880. Does it mean in most cases digital volume control is necessary?

Please help! Thanks in advance.

I got a 1x/3.3x gain O2 from JDS to use with HifimeDIY U2 DAC. I set my player volume and system volume both at 100% so that there isn't any dynamic range reduce due to digital volume control. The gain on O2 is set at low (1x). However the result is too loud. With my HD 558, the volume knob...

Just curious, what is the theory behind this? What else does a pair of headphones need to produce good sound when it has enough power (loud enough)?

I think I read from somewhere that if my headphones are loud enough, then I probably don't need an amp. Just wondering if my amp is really necessary.

Thanks for the link. Very good read. Headphones with below 90 db SPL seem quite rare. The only ones I see are HE6 and K1000.

So usually what value is considered "low sensitivity"?

I have a HifimeDIY U2 USB DAC and Objective2 amp with 1x and 3x gain. My headphones are Sennheiser HD 558 and Beyerdynamic DT 880 PRO. With system volume and player volume both at 100% (0 db), and gain set at 1x on O2, it's way too loud on 558 unless the volume knob is turned very close to...

Thank you very much! I guess I was just worrying too much.

Do you mean the difference made by software volume control is actually very marginal? I haven't notice a big difference in SQ between 100% volume and around 50%, but I did not do strict A/B comparison. (btw I found using 70% volume is actually not enough. When I was testing with 70%, I did not...

I am a noob in signal. Does this mean the SQ in the middle one is significantly affected? Also, does player matters? I am now using VLC and Rhythmbox.

Around 70%(-8 db). 

Thanks a lot for your help, folks. I now need to read more about digital volume control and SQ and figure out what setting to use. Everything at 100% is too loud for my HD 558. I have to set my amp at very low to not deafen my ears. Actually I think I don't need an amp for HD 558, but somehow I...

I opened up alsamixer and found the volume is not set at 0db. I changed it to 0db and now it's as loud as in Windows. I don't remember doing anything audio config but for some reason it seems it's using alsa, not Pulseaudio. Actually it's kind of too loud for my efficient HD 558 :(

I just checked that both left and right channel are set at 0db(100%), but it's still different volume compared to Windows. In Ubuntu I can turn the volume knob to about middle, but in Windows that position will be deafening.

I read from http://superuser.com/questions/492281/from-a-quality-perspective-what-is-better-turning-volume-up-in-the-software-i that reducing volume in software reduces bit depth and is harmful to SQ. I wonder if this is happening to my DAC in Ubuntu now.

I have a HifimeDIY U2 DAC (ES9023) and a laptop with Ubuntu 14.04 and Windows 8 dual boot. Through the same USB port, in Ubuntu, the volume out of the DAC is significantly quieter than in Windows. I don't worry a lot about the volume because I have an amp, but does this difference affects sound...

Is there any difference between 6J1P-EV, 6Ж1n-EB and 6ZH1P? From my eBay search, 6ZH1P is much more expensive. Also the price of 6J1P-EV varies a lot. Any recommendations?

Well it's a DIY amp. Here is a link but it's in Chinese http://item.taobao.com/item.htm?spm=a1z10.1.w4004-1206581359.19.jchNaS&id=1882066537. It probably won't work with 6HM5. I think I will try 6HM5 when I upgrade to LD in future. Thanks a lot for your help!

The manual says it is compatible with M8100, CV4010, EF95, 6J1 and 5725. Do you think it may work with 6HM5?

Actually my amp is not Little Dot. It's something similar to Little Dot Mk1, a hybrid of tube and solid state. It uses two 5654 tubes. Can I directly replace 5654 with 6HM5? 

Thanks a lot! I will look into EI 6HM5. They looks awesome!