Android Tablet Install with pops and crackles
 

Hey guys,

A little background: I have a 2005 V6 that originally had a Shaker500 in it but all together quit working so I moved to my project of installing an android tablet to run all my media in the car. The tablet that I chose is an Acer a500 since it has a powered full size USB and I was able to get it for pretty cheap. I replaced all the main speakers (2 in front and 2 in back), ran all new wiring, and put in a Boss 1000w amp.

I will say that I still need to do some clean up with wires and just the over all look of it but I am wondering why on some songs I get some pops and crackles. It has only been on a few songs and those songs normally have a little bit of a higher end to them. I have tried changing the EQ (since I use PowerAmp application to place my songs and it has a full EQ built into it) but nothing seems to stop the bits of pops and crackles. If any one has any idea why it is happening let me know.

Thanks in advance

How are you controling your volume in the car?

Everything is done through the Acer tablet. The PowerAmp app has everything from library control to the full EQ to volume control. That's why I decided to pay the 6ish dollars for the app. The tablet is directly hooked up to the amp as well and if I wanted to I can use the "remote volume control" the amp came with but I didn't want to add more wiring for something that I don't actually need.

Ok, what's the gain or volume control on the amp set to, 100%?

Your amp should be at 75-80% of its maximum volume. If it's at 100% I can almost guarantee that's the problem.

When you have two devices with independent volume control, the device that will not be adjusted should always be about 75-80% maxiumum volume because at 100% you get 100% of the rated distortion. By itself is no big deal. But, it's magnified when your source introduces its own distortion as you reach its limit.

I have the over all out put of the amp set to lowest settings. I have gone through and made sure nothing was even over 50% on the amp. Again it is only a few songs that have more of a higher end to them then a mid or lower end to them. For all I know it could just be the cleanup that is needed to make the few songs stop popping.

Can you get a different file of the same songs (that someone else made)? That would be the easiest way to test the quality of the song or if you know how many bits it is 128kbps, 192kbps etc?

I find that anything less than 160 or 192 Kbps gets really rough sounding. Especially if it's an intricate sound file or has some really stand-out sections.

Nope don't know what the bit rate is. I would presume it is a little higher since I downloaded it straight from a CD, but I could be wrong. I will say that I have duplicates of the songs from 2 different CDs but both do the same thing when I go to play them. Also they aren't as intricate as most of the "electronica/techno" stuff that I normally am playing, but I will look into it some more.

Ooh. This looks really interesting!

Are you running your audio out of the headphone jack on your tablet or through some kind of USB to RCA style adapter?

When I was looking into doing something like this (I still really want to, but my nook color isn't fast enough for my liking), everything seemed to lean towards going through a preamp or equalizer before you reach an amp, just to clean up the signal and stop any pops or crackles.

Do you have a build thread or blog with your set up though? I'd love to do one myself one day...

As Derf said I believe it is only in the actual audio quality I had ripped from the CD. Didn't realize that wmp, by default, is only ripping CDs in 128. I still have yet to try the songs with a higher sound quality, though everything else works great. I even tried some songs I had downloaded a good 5+ years ago and they seem to be working just fine.

To answer your first question. I am running it out of the headphone jack since the stock wiring for the speakers on the tablet didn't produce a sound quality worth even trying. From the headphone jack I have a splitter to RCA cables.

As for the EQ from what I had read in the few things that were posted about installing android tablets those were used, more or less, in conjunction with the stock radio system. Since I deleted the stock Shaker500 all together, there is no need for a preamp or separate EQ with the PowerAmp app I am using.

When most people install their own audio systems in their vehicles they leave out the simple thought of keeping the power wires separate from the audio wires causing them to normally pop and crackle.

Lastly, I do not have a build thread or a blog for it but if there are enough people interested I can make one since I still have to go through and do all the clean-up of the wires and making it look like it is suppose to be there.

There seems to be at least a little interest in my tablet install so in the next few weeks (after I get all my moving done) I will go through and make a build thread when I get everything cleaned and finalized.