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Mono metalspeaker sounds like crap and too silent

Posted: Sun May 29, 2016 6:00 am
by Kharmeleon
I've bought an 8 ohm metalspeaker from adafruit (the one that is suggested in the GBZ tutorial). No matter how i connect the speaker to the Class D mono amp it will always be too silent and sound like crap. Otherwise when i plug in the headphones they sound good and everything's just fine. My oppinion is that the speaker is broken. That would be very annoying because it was new. What do you think?

For details: I'm using a Raspberry Pi 3. To sum the stereo signal i've soldered a resistor of 470 ohm on each the L and R output of the RCA jack and joined them together. There where they join i've soldered a 20k ohm resistor which goes to ground. Then i connected the top of the joined connections to the A+ pin of the amp. The A- goes directly to ground where the RCA jack was.

Help is appreciated. Thanks in advance.

Re: Mono metalspeaker sounds like crap and too silent

Posted: Thu Jun 16, 2016 12:01 am
by myunholysins
I ran into this problem, if you have retro pi on the sd, boot up the pi with a keyboard, and go into the pi settings. its in The main menu, with all the emulator names. I think it's called retro pi. Once in there the first thing you will see is sound, click that and than it will bring you to a new menu. So go down I think the 4th one, it's called the mixer something. An turn that up to a decent level. When I first tested it mine it was extremely low,): an also had me worried that the speaker was broken.

Re: Mono metalspeaker sounds like crap and too silent

Posted: Thu Jun 16, 2016 11:44 am
by wermy
Yep, definitely do what @myunholysins suggests. You can also adjust the built-in potentiometer on the amplifier itself (the little silver metal disk that looks like a screw).

Re: Mono metalspeaker sounds like crap and too silent

Posted: Sat Jun 18, 2016 3:32 am
by Kharmeleon
myunholysins wrote:I ran into this problem, if you have retro pi on the sd, boot up the pi with a keyboard, and go into the pi settings. its in The main menu, with all the emulator names. I think it's called retro pi. Once in there the first thing you will see is sound, click that and than it will bring you to a new menu. So go down I think the 4th one, it's called the mixer something. An turn that up to a decent level. When I first tested it mine it was extremely low,): an also had me worried that the speaker was broken.
Thank you so much for that tip! I wasn't even thinking about that simple solution.. With the potentiometer of the amp at max the sound volume is "ok" now. I'm not quite satisfied but it's much better than before. When the pi 3 boots for example or between loading times of the emus i encounter scratchy noises (interferences or something like that). Think you get what i mean. But ingame it seems that everything's alright. Any idea about that and how to solve this? Is there a code or a line i can add to the config.txt to force the audio jack to output mono sound on both left and right? Thanks for your help guys! I appreciate that.

Re: Mono metalspeaker sounds like crap and too silent

Posted: Mon Jun 20, 2016 11:56 am
by Ford873
Not sure if this applies to the pi 3 but I am using a pi 2 and had terrible audio hiss from it when in menus and when the pi was working.

I added the following code to the boot/config.txt and it stopped it completely.

disable_audio_dither=1

Hope this helps.