[fur]

I found out that the headphone out on my ihp sounds kinda dark and a little veiled & bassy compared to the line out. Also the line out gives more transparency, less noise (turn volume to 0, you'll hear a big difference between head and line out) and better stereo image. I wonder i'm the only one noticed that because i think it's pretty easy to hear the difference. I'm using the shure e3c, eq/srs switched off ofcourse.
EQ affected the line out noticebly less than headphone out. I really wonder whats going on there

 

[ASDFer]

Better stereo image, perhaps. There's no amplifier on the line out so there's probably less crosstalk on the power rails. However, you pay the price with rolled off treble and bass (unless this is what you like) since the line out can't properly provide the current to low impedance loads. You'll also get a lot more distortion.

Proof:
http://uberfast.ece.ucsb.edu/~mgrund/audio/lineout.htm

(The load is a set of headphones, so the treble is actually rolled off, not emphasized as the graph would appear to indicate. If you need a better explanation I will gladly go into the math.)

Yeah, so I use the headphone out.

 

[terrymx]

well you would have to use the headphone out. you would use the line out if you have an amplifier or connect it to the speakers.

 

[fur]

thanks for your points, but i really wonder why the volume on the line out changes when i change it in the player?_? what would be the right volume to have lineout act like a lineout? i also noticed lineout and headout have same volume with the shure's which means i can't go over 20 without going deaf

 

[waffenschmidt]

This has been covered in another thread in the last few days. As I understand it, volume control is done digitally in the iHP and some other portable devices, not in the amp, thus the volume control affects both the headphone out and the line out signals.

The line out is a line out no matter what the volume is set at, but most recommend setting the volume at maximum.

 

[Traveller]

Quote:

Originally posted by ASDFer Proof

Jesus H. what the hell is going on @ the 1KHz intervals??? The THD graph looks nuts - even for Head out load

Btw, do you think it would somehow be possible to run such a test using an external amp, preferably a portable, w & w/o load...?

If so, I'd be thrilled...

 

[ASDFer]

Those 1kHz intervals are the harmonics. The THD for the headphone out isn't that bad- those peaks are below -90dB. If you look at the end result, the THD is about .01%- really not that bad for portable audio. It's on par or better than the Karma at least and should be about the same as the iPod - all three measure about the same, with slight bass rolloffs for the iPod (maybe not now?) and Karma.

It is indeed possible to test with a portable amp, but I don't have one.

 

[Traveller]

Quote:

Originally posted by ASDFer Those 1kHz intervals are the harmonics. ...It is indeed possible to test with a portable amp, but I don't have one.

Ah, yes, the harmonics (2nd & 3rd order?) of course.

Well, I do have an amp + just downloaded RIAA 5.3. but have no clue how to use it. I've only managed to create an auto test signal - some wierd combo of tones @various frequencies.... If you could give me an idea how to test, I would be happy to

 

[ASDFer]

You'll need a test harness that can sample the voltage across your headphones if you want to do load testing. Otherwise, just put the sound files on your player, then hook it up to the line-in on your sound card. Calibrate the input/output levels and then test.

 

[Traveller]

Quote:

Originally posted by ASDFer ...just put the sound files on your player.... Calibrate the input/output levels and then test.

I saved the RMAA's "test" signal + calibration 1KHz tone wav files to the iHP-120. I then played the calibration tone (from the iHP) and adjusted line-in until I had ~ -1dB (iHP o/p vol set to max - 40).

So far, so good. I then selected the "Recording only" RMAA test, started playback of the "test" wav file on the iHP (before the RMAA recording was further than 40%) and I got an error message that RMAA couldn't find the test signal. But I could hear the test signal, so I don't know what the hell's going on

Btw, why is the auto-generated test signal a 20sec WAV file and the RMAA recording test goes on for a good 60secs??? I even set the iHP on repeat mode, but still, same bloody error. What am I doing wrong...?

Last but not least, when calibrating the level from Line-out and Headphone-out, I had the line-in level at 47% and 55% respectively. This implies that the line-out signal is stronger than the Headphone-out, which makes absolutley no sense....

 

[Traveller]

Btw, the answer to our questions, or at least more info towards it, might be in Head-Fi's post, Inside the iHP-120.

cheers