Quick Question on Gain

deathcloud · Post by **deathcloud** » Fri Nov 27, 2009 5:48 pm

So I am familiar with the gain setting. However I just thought of something. Forgive me if someone else brought this up. But it makes sense in my mind.

So I understand the simple principle of gain matching your headunit or line driver to your amp.

Aka at the RCA ends I get bout 8volts rms at 3/4 volume thanks to my trusty line driver hahaha.

Anyways I was thinking... I put a 60hz CD in and run it 3/4 volume to that. BUT I use my ipod/iphone 100 percent of the time. CDs are so 90s.... so I was wondering should I set my gain according to a 60hz test tone playing from my ipod/iphone so that I don't get a clipped signal via using two different methods of playing. if that makes sense...

I hope it does.

Someone should know this.

deathcloud · Post by **deathcloud** » Fri Nov 27, 2009 5:52 pm

BTW I understand if you get a cd it is usually all the same bit rate and sound levels? Correct me if I am wrong.

I know some said that if you get mp3s then they are usually some soft some loud and that could effect your sine wave from distorting. I don't want that so I honestly download all my stuff from itunes so I know it has the same compression and hopefully volume levels and stuff if that makes sense.

I know the illegal shit can be too soft.... too loud... and I was affraid of getting a song that is too loud and mess up my gain settings... and clip the signal.

Post by **fuzzysnuggleduck** » Fri Nov 27, 2009 6:23 pm

I would still set it using the CD with a properly normalized 60Hz tone. If anything, your iPod will produce less output than the CD player. If from there you find the iPod to be too quiet at 3/4 you can lightly adjust from there to taste realizing that your CD will now not take as much volume on the dial to get loud as it did before. Do you use the line out from the headphone jack? Unless the HU has independent input channel gains for AUX and CD, you might have a hard time matching them well unless I suppose if the HU by default has more gain on the AUX input.

My HU reads the iPod files digitally and uses it's own DAC to decode them so that arrangement does not include the same problem as an AUX channel for volume level matching between that input and CD.

Now I'm ranting...

In the file sharing world quality does vary, especially on the P2P networks where people have lots of individual songs and not consistent full album rips... and even then from torrent to torrent you're possibly getting different quality acros albums. Torrents will often give you the quality metrics are made obvious so you can know what to avoid.

I prefer to rip my own albums into AAC.