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Speakers.
Posted: Sat Aug 20, 2011 7:50 pm
by warhead052
Anyone out there who knows a thing or two about speakers? I want to build a little setup with a car speaker for my mp3 player, but I don't know what to do. I can solder, and I am not bad at it, so thats not a problem. My only problem is figuring out how to power the 6x9" speaker without having to suck all the mp3 power. Can anyone help me with this?
http://www.radioshack.com/product/index ... Id=2925200
Thats the speaker I would like to use.
Posted: Sat Aug 20, 2011 7:52 pm
by Gun Freak
Buy an mp3 speaker for like 20 bucks 8)
Posted: Sat Aug 20, 2011 7:54 pm
by warhead052
Nah, its not as fun as 92db.
Posted: Sat Aug 20, 2011 8:06 pm
by jsefcik
Those lil speakers only draw 12v volts=)
you can hook up computer speakers in your car
just buy a small cig lighter adapter with a wall socket built into it and then put the computer speakers into that,
my mp3 is reallly loud with my computer speakers in my dads truck!!1

Posted: Sat Aug 20, 2011 8:26 pm
by warhead052
Yeah, but I want to put this into something like a shoe box or a brief case and carry it around.
Posted: Sat Aug 20, 2011 8:27 pm
by jsefcik
umm, can a 12v battery pack!! lol
Posted: Sat Aug 20, 2011 8:56 pm
by mattyzip77
Dude just splice the earphone wire to the speakers and make a battery pack from a old r c car or somthin like that. Also it may sound like sheeeat if the mp3 dont have the power to push the speakers!!
Posted: Sat Aug 20, 2011 9:06 pm
by warhead052
Well, I want to know how to do it without causing electrical backflow into the mp3 player potentially damaging it. Any tips for that?
Posted: Sat Aug 20, 2011 9:10 pm
by mattyzip77
you wont as long as you dont cross any wires. take the battery out, then make all of your connections!
Posted: Sat Aug 20, 2011 9:28 pm
by warhead052
I will try at some point. I just don't want to ruin anything.
Posted: Sat Aug 20, 2011 9:42 pm
by mattyzip77
I hate to say it, but you are just better off getting those speakers that gunfreak suggested. The mp3 wont have the power to push those other speakers. If it does, you will never reach the full output capacity of them!!

Posted: Sat Aug 20, 2011 9:47 pm
by warhead052
Sigh. I suppose so. Shame I can't use a outer battery to power the speaker while the mp3 merely provides the music.
Posted: Sat Aug 20, 2011 10:37 pm
by Crna Legija
warhead052 wrote:Sigh. I suppose so. Shame I can't use a outer battery to power the speaker while the mp3 merely provides the music.
buy one of the small amplifier kit from electronics stores like radio shack.
like this:
http://www.ebay.com.au/itm/LM3886-Hi-En ... 2677wt_905
Posted: Sat Aug 20, 2011 10:47 pm
by Technician1002
Disclaimer, I made a living in Audio for many years. I now work in R&D.
You are speaking my language. Here are the issues.
#1 is the amount of current the MP3 player can produce. The electrical impedance of most ear bud headphones is 16-32 ohms. Car stereo speakers are almost all 4 ohms. Impedance is the inverse of the current draw at a given voltage. Right off the bat the speakers will try to draw the same electrical power as having 4 sets of headphones connected all at the same time.
#2 is sound quality. When drawing excess current the amplifier in the player will clip at low levels and high current for deep bass will be lacking. Sound will be thin, possibly distorted, low on bass, and low volume. Some players work with low impedance speakers better than others.
#3 is battery life. This high current will shorten battery life.
The recommended solution is to use computer speakers that can run on AA batteries. This provides a high impedance load on the MP3 player (less load) and is designed to drive the included speakers. Using rechargable AA batteries in the speakers will provide decent volume and fidelity.
My only problem is figuring out how to power the 6x9" speaker without having to suck all the mp3 power.
I you are like me and have a 12 volt gel cell, simply using a mini stereo to RCA cord with a small car amp will do the trick and drive those 4 ohm 6X9's just fine. Most RCA inputs on amplifiers are about 47K ohm so the load on the MP3 player is almost non-existent. The amp can run undistorted and full bass fidelity is preserved.
If I really need to make noise, I plug into the studio setup with a small 500 Watt RMS amp.

Posted: Sat Aug 20, 2011 10:49 pm
by Fnord
buy one of the small amplifier kit from electronics stores like radio shack.
Radio shack still sells kits for stuff?!?