Support and General Use > Recording

Recording Level vs Playback Level

(1/3) > >>

johnp_g:
Hello,

I've been a happy Rockbox user for a few years now and I'm really pleased at
the functionality improvements over the OF of the iRiver H120.

I record a lot of stuff via the line in socket, from shortwave radio
receivers etc. and adjust the recording gain to peak at Full Scale Deflection on the peak
level meter on the WRS. Audible distortion occurs if I increase the gain, or input level,
beyond this, so this would imply that the metering is a true indication of the input level, and it's limitations.

However, when playing back any of my recordings on the player, or on the PC in an editor such as Audacity, I see the amplitude is only 50% of the maximum.

I can use Audacity to normalize, i.e. amplify to put the peaks at "1" (100%), or more usually at -3dB of max, but I'd rather fix the peak levels at the recording stage, not afterwards.

I'm confused about the disparity between the recording level metering, and the playback level meters. Files that are amplified in Audacity to peak at "1" sound okay when played back on the iRiver, and the WPS peak level meters now reach the max deflection.

Am I doing something wrong? I generally turn AGC off, and adjust the input
level and/or gain to peak at 100% (on the WRS meters) for the loudest input signal I'm likely to have.

I've searched back through the forum "recording" section, and tried to trawl the mailing list archives for some pointers on this, to no avail.



Cheers,

John
Shetland UK

petur:
Thanks for bringing this to the forum

I tried yesterday using mic-recording on my h380 and the signal was as saturated as the peakmeter indicated.

Can you verify that your peakmeter settings haven't been changed? You can set min and max peakmeter levels - this can cause the peakmeter to show 100% at 50% signal.

johnp_g:
Thanks for the reply Petur!

I've just done some tests with a variety of sources (internal mic, external mic, FM tuner and line in fed from a Lindos Audio test set).

The confusion over levels appears to have been a misunderstanding of mine about the recording setting for "Channels: mono/stereo".

I select "mono" - since I only generally record mono sources, fed into one channel, and set the recording gain to give 100% on the peak meter on the channel concerned, playing back the file I notice it only registers 50% on the meter, on both channels! My confusion I think, about how stereo/mono recording and playback is defined?

If I record in "stereo" but only to one channel (eg Left) and again set the single channel to peak at 100% when recording the resulting file shows 100% level on that channel, and nothing in the other one.

How can I record a mono source, to a mono WAV file, and still have 100% amplitude on the output file?

I will start to record "single channel ,stereo" from now on.

Cheers,

John

petur:
Ah, these details are interesting... I'll try to reproduce it this way as soon as I find the time

petur:
I just reproduced this and I think the code tries to add the left and right channels together, so if you ave a 100% left and 0% right, you'll end up with a 50% waveform...

Maybe we should offer settings to do L/R/L+R if mono is selected?

Navigation

[0] Message Index

[#] Next page