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Gear / Technical Help => Recording Gear => Topic started by: atxwolfattack on August 09, 2007, 11:42:58 AM

Title: Weird thing thats happening between 2 recorders
Post by: atxwolfattack on August 09, 2007, 11:42:58 AM
Okay, so normally if i can get a board patch, i tape from my mics, and from the board because i have 2 iRiver ihp-120's. The other day i was at a show and i wanted to get a patch but the sound guy wouldn't let me, so i tried an experiment.

First, i hooked up my main iriver to the preamp and my mics, with 10db of gain added from my preamp and none on my recorder. Then, i went line out from that recorder into the line in on my other recorded. Normally i run semi conservative on my levels, so i thought that i could keep my first recorders levels conservative, while i could boost the second one a good bit and see if i don't clip.  So once i hooked up the second one, i noticed that while the gain on that 2nd recorder were at 0 too, my levels were significantly lower than the first recorder.

This seems weird, because, wouldn't you think that if the preamp was sending out 10db of gain, and the first recorder and the second were chained together through the line in and out, they would have the same levels? I literally had to add 10db more of gain to the second recorder for the levels to get level with the first recorder.

Am i wrong about this? It seems like this second recorder would now have 20db of gain added with the first only having 10db, but they have about the same levels now???

I'm confused.
Title: Re: Weird thing thats happening between 2 recorders
Post by: OOK on August 09, 2007, 12:45:19 PM
I am not familar with the irivers, but I have a question.  Is the line out also the headphone out.  If so was your headphone volume turned down?
Title: Re: Weird thing thats happening between 2 recorders
Post by: atxwolfattack on August 09, 2007, 01:04:46 PM
Naw, its not the headphone out, they have a dedicated Line Out.


I am not familar with the irivers, but I have a question.  Is the line out also the headphone out.  If so was your headphone volume turned down?
Title: Re: Weird thing thats happening between 2 recorders
Post by: Arni99 on August 09, 2007, 05:13:42 PM
was the output-level of your 1st iriver at 0(in rockbox) =>max-volume?
you can change line-out level´s volume ;).
Title: Re: Weird thing thats happening between 2 recorders
Post by: atxwolfattack on August 09, 2007, 05:15:52 PM
oooh, thats probably it, i thought that the volume was just for headphone jack, so in rockbox, the volume changes the line out as well? Thanks!

was the output-level of your 1st iriver at 0(in rockbox) =>max-volume?
you can change line-out level´s volume ;).

Title: Re: Weird thing thats happening between 2 recorders
Post by: Arni99 on August 10, 2007, 03:27:52 AM
oooh, thats probably it, i thought that the volume was just for headphone jack, so in rockbox, the volume changes the line out as well? Thanks!

was the output-level of your 1st iriver at 0(in rockbox) =>max-volume?
you can change line-out level´s volume ;).

yes, you can change volume on line-out aswell with rockbox.
set "Volume"(NOT "GAIN"!) on the rockbox recording screen to max. value of "0" for achieiving max. line-out volume.
Title: Re: Weird thing thats happening between 2 recorders
Post by: petur on August 10, 2007, 04:42:24 AM
Naw, its not the headphone out, they have a dedicated Line Out.
Yes, impedance-wise it is line-out, but the volume setting applies to both line-out and headphone. It's a hardware thing, nothing Rockbox can fix sadly....
Title: Re: Weird thing thats happening between 2 recorders
Post by: atxwolfattack on August 10, 2007, 10:29:16 AM
well, i dont really know what is going on here. I taped a show last night and i tried the same thing, and had to boost my second iriver like 4 decibels more. Its not really a big deal, i just wanted to figure out what was going on.
Title: Re: Weird thing thats happening between 2 recorders
Post by: petur on August 10, 2007, 04:55:00 PM
well, i dont really know what is going on here. I taped a show last night and i tried the same thing, and had to boost my second iriver like 4 decibels more. Its not really a big deal, i just wanted to figure out what was going on.

In fact it's quite simple:

Since quite some time, the line-in signal is no longer just passed through to line-out in hardware (using the mixer feature of the audio chip), but passes through the processor. So what you get is:

Line-in -> ADC -> DAC -> Line-out/Headphone

Of course this means that the amplitudes of both signals have no relation to each other
In fact, it also means that taping the output of the iriver is probably not such a good idea (it may be a backup but quality will be less)

I should have remembered and told you this before, my memory must be going :/
Title: Re: Weird thing thats happening between 2 recorders
Post by: atxwolfattack on August 11, 2007, 02:57:34 AM
Ahhh, i see. Well, i was just doing it to be safe. I thought that since i wassn't using my other iriver, i might as well try to record with it in case something were to happen during my main player. Now that i think about it though, if something were to happen to the first player, then it would happen to the second player..... haha, dumb of me.

thanks for the info though!!!!


well, i dont really know what is going on here. I taped a show last night and i tried the same thing, and had to boost my second iriver like 4 decibels more. Its not really a big deal, i just wanted to figure out what was going on.

In fact it's quite simple:

Since quite some time, the line-in signal is no longer just passed through to line-out in hardware (using the mixer feature of the audio chip), but passes through the processor. So what you get is:

Line-in -> ADC -> DAC -> Line-out/Headphone

Of course this means that the amplitudes of both signals have no relation to each other
In fact, it also means that taping the output of the iriver is probably not such a good idea (it may be a backup but quality will be less)

I should have remembered and told you this before, my memory must be going :/