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Support and General Use => Audio Playback, Database and Playlists => Topic started by: Pingouin on May 09, 2019, 01:37:49 AM

Title: I'm an enginner and don't know how volume works
Post by: Pingouin on May 09, 2019, 01:37:49 AM
Hi all,
I've got a Ford Focus and when listening to the radio, I can't get it past 9 out of 30, otherwise it's just too loud (I'm not a rave party guy).
However, when I connect my Fuze+ to the audio input, I have to crank the volume to 20 on the stereo, and pretty much all the way up on the Fuze+, otherwise it's too dim and I can barely hear anything. I tried with my phone, and it's a bit better, i.e. I don't need to crank it up all the way up, and I have acceptable volume level by setting the car stereo at 15.
So my question is, am I doing anything wrong? I reset the Fuze+ and selected "Rest of the world" as region, but I'm pretty sure that doesn't impact Rockbox.
Also, from a sound quality point of view (e.g. noise) and being gentle on the hardware, is it better to crank both Fuze+ and car to, say, 75%, or the Fuze+ all the way up, the car all the way up, or both?
Thanks!
Title: Re: I'm an enginner and don't know how volume works
Post by: saratoga on May 09, 2019, 10:37:15 AM
Your car has a line in jack which is expecting to be connected to a line out on a device. If you use a headphone jack, you need to have the volume at close to 0dB to reach the line out voltage level. Ideally you should put the fuse to 0dB and then adjust volume using the car stereo. In practice everything else in the car is so noisy you don't really have to worry about this.
Title: Re: I'm an enginner and don't know how volume works
Post by: gomezz on May 09, 2019, 02:37:27 PM
Your car radio may have a setting to adjust the sound level from each input so you can switch sources at will without having to keep adjusting the master volume control.
Title: Re: I'm an enginner and don't know how volume works
Post by: Pingouin on May 09, 2019, 02:57:46 PM
Thanks to both of you!

saratoga: yes, I think you are bang on in that there isn't anything wrong, just that the AUX line expect a higher signal level than a headphone jack. Hence why I have the same problem with my phone, but both Fuze+/phone work great with headphones.

gomezz: yes also! I noticed that my car stereo (a Sony branded Ford OEM audio) has some sort of equalizer (obviously), but the good thing about it I didn't know is that it keeps the setting separately for each source! So I cranked up the AUX input to +7 (db? it doesn't say), but left the radio as is, so that if I switch from AUX to radio, I don't get my eardrum blown away.

Again, thanks to both, you were spot on!
Title: Re: I'm an enginner and don't know how volume works
Post by: Pingouin on May 09, 2019, 03:05:15 PM
Sorry, another question to saratoga:

>you need to have the volume at close to 0dB to reach the line out voltage level. Ideally you should put the fuse to 0dB and then adjust volume using the car stereo

Is that just in theory? Would that be bad for the MP3 player, being used constantly as top volume? Would it make the battery deplete faster, make the battery and player heat more, and potentially lead to premature failure? And wouldn't that decrease signal to noise ratio?

Thanks!
Title: Re: I'm an enginner and don't know how volume works
Post by: saratoga on May 09, 2019, 05:03:57 PM
Sorry, another question to saratoga:

>you need to have the volume at close to 0dB to reach the line out voltage level. Ideally you should put the fuse to 0dB and then adjust volume using the car stereo

Is that just in theory? Would that be bad for the MP3 player, being used constantly as top volume? Would it make the battery deplete faster, make the battery and player heat more, and potentially lead to premature failure? And wouldn't that decrease signal to noise ratio?

Probably uses very slightly more energy, but it improves SNR (not that you care).
Title: Re: I'm an enginner and don't know how volume works
Post by: Pingouin on May 10, 2019, 06:47:28 AM
Ok, thanks!
Title: Re: I'm an enginner and don't know how volume works
Post by: gomezz on May 10, 2019, 02:42:11 PM
I have actually got into the habit of setting my Sansa Clip+ to -3dB below line level as otherwise on those occasions I was feeding my Satechi FM transmitter rather than a direct connection is was overloading it and running it into clipping and distortion.
Title: Re: I'm an enginner and don't know how volume works
Post by: Pingouin on May 10, 2019, 04:26:48 PM
Yes, that's why I was asking is setting up at db wouldn't result in poor SNR, but saratoga hints that it's actually the opposite?
I still don't push my Fuze+ all the way up (but close) as I now get decent volume by having set up the EQ on my stereo for AUX input up.