[Shizam]

I just got a nice pair of IEM's last month (JH-16's) and my old amp had to high a noise-floor so I bought a new one which has _no_ noise floor, its amazing.  However now the problem is the USB amp/dac doesn't honor the system level sound output slider in OS X and as a result sound output from the amp/dac IS REALLY LOUD!  Even turning the volume knob up about 5 degrees is really quite loud and I need more range of volume control.
 
So I found this app called SoundFlower that lets me route all audio via SoundFlower and lower the volume of the SoundFlower app effectively giving me back  System Level sound output control, my question is, does this affect the sound quality?  Here is the app if anybody is curious:
 
http://cycling74.com/products/soundflower/
 
Thanks,
Sam

 

[albertnam]

Well anything that applies DSP to the signal chain will affect sound quality in some way. It might be bad, but it might not be noticeable either. If it doesn't really make a whole lot of difference to you, that just keep using it. However, digital volume sliders tend to be detrimental to sound quality. 
 
I use the physical attenuator that I got with my TF10s. You can pick one up for $20 as part of the Ultimate Ears toolkit for universal IEMs.

 

[Shizam]

And that thing doesn't adversely affect quality?  Can't tell from what google is giving me

 

[albertnam]

Well it's basically making your IEMs have a higher impedance in effect, so I don't believe it will degrade sound quality, especially considering UE's track record. 
 
I have found that it actually tightens up the sound while increasing impedance of course, which has the effect of lowering overall volume.

 

[Shizam]

Thanks,
Thats perfect!  I ordered a kit.