Wow, lots of useful informations, thank you all.
@jcfelice88keys
Nice link to beavis, thanks. Transformers or JFETs, hm, I guess I would prefer OPA today for linear audio.
@Luc Henrion
USB audio interface is not an option for me at the moment, thanks. I have excellent latency out-of-the box with onboard sound on that HP 635 notebook. I already have a highly tuned eeePC with USB-soundcard Behringer UCA222, which I use exclusivly as "sound-engine". I was hard work, but it has good latency after many tweaks and there are two describing threads in this forum (netbook thread and zero latency thread iirc). Those tweaks were on kernel 2.6x and may not work the same on kernel 3.2 eventually. Another reason is, I'd like to use the HP 635 for other, more standard purposes and keep the setup straight-forward this time.
@skip
skip wrote:There is no guarantee that the sound you hear with the headphones plugged into the notebook is the "right" sound, just because you prefer it - it is possible that the sound you hear from the mixer is actually more accurate.
Good point. If there is "sounding", it is more likely the impedance interaction between headphone-output and headphone, than the interaction of headphone-output with a typical line-input. To make the comparison more fair, I plugged the headphone (audio-technica ATH-M40fs) now into headphone-out of the notebook directly and after that into the headphone-out of the Yamaha mixer. It is not as far away, as it was yesterday (?!). The direct headphone-connection is a little brighter, but as you said - "sounding" is more likely happening with this direct connection. All controls were neutral and no hiss nor hum. Important is to adjust the headphone level to max in the software-mixer. It is not impossible, that it was not fullscale yesterday, sorry if that happened!
skip wrote:Just btw, the notebook's output level may not be all that low.
I will measure it when I have more time. It would be interesting, if those energy efficient APU notebooks use low voltage for sound output, though I don't think so.
Luc Henrion wrote:just out of curiosity: did you use the input 7/8 on the Yamaha or one of the 3/4 - 5/6 ? On the input 7/8 you don't have any control of the input level (it's fixed to -10dB) ... try input 3/4 or 5/6 (+10 to -34)
Normally I use 7/8, because it is the best sounding input. Yesterday I tried also the 5/6 with its additional input gain control but it was no big difference soundwise. Something else went wrong, as I guess above. For a while I was connected with my keyboard combos and you all know, how big the contrast between headphone and loudspeakers can be
With output level full scale on the notebook, I can use 7/8 ok. Another interesting measurement would be the output-impedance of that notebook. Maybe a little sound degradation is possible if it should be exceptionally higher than average 120 Ohm. A workaround could be just to use the treble controls on the mixing console or the keyboard amps
Thanks for reading english, not my world
- groovy