Support and General Use > Audio Playback, Database and Playlists
Rockbox Audio Quality versus Original Firmware (RMAA comparison)
saratoga:
--- Quote from: wolfB on August 29, 2006, 12:27:26 PM ---I'd agree the soundquality of the dock output from a 5G iPod can be considered equal. But I can definitely recognize a difference from the headphone out, at least with my sensetive IEMs (UE-10Pro and super.fi 5Pro). Quite possibly an impedance issue, as it might be related to the different hissing noise floor, which is significantly lower in Rockbox.
--- End quote ---
Do you mean the difference between the headphone and line out jacks? That would be expected, the line out has no amplification and a higher impedance, so it should have a slightly lower noise floor.
If you mean a difference between firmwares, that shouldn't happen.
--- Quote ---2. Would it be possible to ABX two files, recorded from the iPod's headphone jack?
--- End quote ---
Yes. Hook up the Ipod to your computer and see for yourself. However, if you are concerned about impedance, then you MUST also hook up your headphones in parallel with the mic jack in order to provide a load for the headphone jack on the Ipod (otherwise you'll just test the unloaded noise floor, which you suggested is not the same).
wolfB:
--- Quote from: saratoga on August 29, 2006, 09:41:04 PM ---If you mean a difference between firmwares, that shouldn't happen.
--- End quote ---
Yes, that is exactly what I meant. To be clear, the scenario is as follows:
Low impedance high sensetive IEM on the headphone out of the 5G iPod.
Apple-FW: clearly audible hissing noise floor.
Rockbox: definitely much less hiss.
I am not sure if this is due to impedance miss match, as the hardware didn't change.
That's what is objectively reproducable. On a subjective side note I'd say the overall soundquality is improved on headphone output with Rbx (I know, I am not alone with this...see head-fi forum), IMO at least on the same level as from the dock out.
To shed some light on this subjective impression it would be great, if this could be checked in a ABX test with two files recorded from the headphone output.
I doubt I have the appropriate hardware to record the files, but I'll try.
saratoga:
--- Quote from: wolfB on August 30, 2006, 02:11:14 AM ---
--- Quote from: saratoga on August 29, 2006, 09:41:04 PM ---If you mean a difference between firmwares, that shouldn't happen.
--- End quote ---
Yes, that is exactly what I meant. To be clear, the scenario is as follows:
Low impedance high sensetive IEM on the headphone out of the 5G iPod.
Apple-FW: clearly audible hissing noise floor.
Rockbox: definitely much less hiss.
I am not sure if this is due to impedance miss match, as the hardware didn't change.
--- End quote ---
That definately sounds fishy. Could you confirm it with either ABX or RMAA results?
--- Quote from: wolfB on August 30, 2006, 02:11:14 AM ---I doubt I have the appropriate hardware to record the files, but I'll tr
--- End quote ---
You only need a PC + audio cable, so hopefully thats not too big a problem.
Edit: Well I suppose if you think the issue is the load induced by your headphones, then you need a headphone splitter so that you can have both the headphones and PC listening at once (or an audio cable that you were willing to cut and splice into).
wolfB:
Thanks for the tips, saratoga.
I'd suppose that it could be confirmed with ABX.
I'll try to record two wav files, and will post detailed results here. Just give me two or three days.
Edit: I am obviously unable to record decent wav-files, as I get rather destorted files with overemphased bass only. iPod Headphone out -> LineIn of nVidia onboard soundcard, WindowsXP, Audio Recorder 3.0. All EQ-settings flat or disabled, volume on the iPod with Rbx tried at -25db, 0db, and +6 db, but no avail. I'd think a software recorder with a peek-meter would be helpfull. Could anybody point me to a freeware download, please.
Febs:
Goldwave or Audacity would do it.
Also:
1. Check your soundcard to make sure you are plugging into the line-in, and not the microphone in.
2. If your sound card does not have separate inputs, check your soundcard's set up program to see if there is a way to set it to line-in in software.
3. If not, use the volume mixer to turn down the input volume on the mic/line input.
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version