solved? Re: [linux-audio-user] [OT] recording levels (mismatch)

Erik Steffl steffl at bigfoot.com
Fri Oct 15 11:19:36 EDT 2004


Erik Steffl wrote:
> Andres Cabrera wrote:
> 
>> Hi Erik,
>> Usually audio equipment is setup to output/receive at two possible 
>> levels -10dBu or +4dBV, Semi-pro equipment and home equipment usually 
>> work at -10, which comes up as very low when the receiver is setup for 
>> +4. But I would guess the soundblaster card is setup to work at -10 as 
>> well (I'd be surprised if it isn't).

   sony STR-SE581
   voltage 150mV
   impedance 10kOhms

   I couldn't find the specs for soundblaster RCA inputs (the docs just 
say it's an aux in, no details), on some sites there are some numbers 
but I haven't been able to figure out whether they apply to RCA or other 
inputs. I also found out that if I connect it to line 2 (the jack right 
below RCA inputs) and use the mic gain knob the signal gets amplified 
enough to be usable. Unfortunately it's mono (it's just one channel).

   the creative.com knowledge base search revealed:

   Line In Full Scale Input 2.0 Vrms
   Line In Impedance 10k ohms

   what is Vrms? I guess it has something to do with voltage... should 
2.0 Vrms play nicely with 150mV?

>> Maybe there's some software fader somewhere else in the chain?
> 
> 
>   I don't think so, at least I am not aware of anything. The volume is 
> too low even when I just use the alsamixer to listen to it. When I 
> connect other devices (ipod, line6 guitar pod, yamaha dd-55 percussion 
> pad) the volume is OK.
> 
>   Actually maybe I could use headphone output, I didn't think of that 
> (it should be pretty much the same as iPod or guitar pod, I use the same 
> headphones with all of these).

   looks like headphones output works pretty well. I don't get 
unprocessed signal (i.e. volume, treble/bass, effect (dolby, room 
type...) etc. are all there so I have to be careful about the settings 
on the receiver) but the signal is strong enough (matching what 
soundblaster expects).

   any comments? gotchas?

   btw I am using gramofile to split the resulting wav into songs and 
clean-up the signal. The song splitting works pretty good but I was 
wondering what other people use to clean the sound (specifically the 
signal from vinyl records).

	erik



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