Acoupower

In a typical home hi-fi system what is the potential difference across the amplifier terminals that feed a loudspeaker? What is the typical current the loudspeaker wires carry? What is the typical resistance of a loudspeaker?

Loudspeakers are typically 4 or 8 ohm, though there are other impedances.
Note it’s Impedance, not Resistance - as they have a wound coil (effectively an electromagnet), the actual resistance is low at low frequencies and higher at high frequencies.

As an example, assuming an 8 ohm speaker (calculated as a resistance for simplicity) with ten watts RMS power in to it from the amp.

The RMS voltage (think of it as the equivalent DC to give the same power) would be 8.94V
The current would be 1.12 Amps

As the amp signal is AC, the actual voltage & current would be peaking at about 1.4x those figures and dropping to zero at each half cycle.

Power out is ’square law’ ratio to voltage or current, so eg. at 40W RMS, both the voltage and current would be doubled. (Watts are Volts times Amps, so doubling both gives four times the product).

Just wondering if technology has it such that the frequency no longer allows this.

(Two years ago, someone’s cell conversation at my work was heard over the intercom speakers … and there was a lot of cussing going on.)

Nothing is impossible, as your story demonstrates. But even two years ago, that was an extremely freaky set of circumstances that could allow it. Very doubtful that you could re-create that incident using the very same cell phones in the very same locations with the same intercom speakers.

The radio of my Ranger 1996 is broken and I´ve bought a new one but I can´t get sound, I´ve tried to identify which wires connect to the loudspeakers but I got no signal. Thanks for the answers.

I actually replaced all my speakers in my 1997 ranger (exact same truck new year), I made my own connectors for the existing radio but after replacing the radio a couple years later I ran into your problem. You must check the OHM rating on the new radio, it can’t exceed that of your speakers. Also make sure that the fuses in the fuse box (to the right of the steering wheel) have not blown and then make sure you have the correct connectors for antenna as well as the speakers (they are not all the same).

Hope this helps.

I am an electronics student and I want to make a car audio power amplifier myself because I heard that the labor cost too high and its why amps cost alot. But the point I am making is that I want to find a website that sells the car amp board and kit along with the schematics but I can’t find it. Can you help me find the website?

There are some nice schematics on this site. You’ll have to convert your power supply for car use, but this site should help get you going … http://www.diyaudio.com/

i have a sub woofer that has speaker wire which has two connections the black and red and hooked up to my receiver. i wanted to hook it up to my other receiver but it only has one RCA black input. i went to radio shack and they told me i have to convert it some how but i don’t know how if it is possible?

Two speaker wires into a single RCA? Well its splicing time my friend! The negative wire from RCA is the one that is under first layer of insulation and the positive would be under the second making it a very thin wire and you will need to use care in order to strip it. If this is for the sub like you say then it should work out ok for you. Subs dont need fancy signal wires to sound good as long as its able to filter high frequencies out it will be all good. Time to upgrade to a receiver with the proper pre-outs though man.

EDIT EDIT EDIT—-

Just got a clearer idea of what youre asking and the above poster brings up a good point. IF this is what youre trying to do then STOP! The impedance on the sub from a home theater in a box will rarely be the same and will definitely be lower and probably 3 ohms causing a heavy load on the amp that is designed for 8 ohm speakers. If you are trying to hook the sub up to the receiver through the preamp on the receiver dont bother as the sub from the HTIB will not have a built in amp and will receive nothing but a signal from the receiver itself or in Jethro tech talk- You aint gonna get no boom for the boom box!

I want to put 2 x 250watt 8w7 JL sub woofer in my car, will my car power supply be enough to power all the stereo, amps etc?

Yes, the average vehicle on the market is equipped with roughly a 100 amp alternator, at 14.4 volts that’s in excess of 1,400 watts for your entire electrical system, or 12v @ 1,000 watts. If power consumption is your concern, consider purchasing a class D amplifier, they utilize energy more effeciently than ab classes. If you have any issues, it will be headlights dimming, consider purchasing a stiffening capacitor, 1/2 farad would be ideal for your application and would most likely resolve the issue. Aside from that, simply ensure that you have a professional install done, or if you do it yourself make sure your ground connections are solid, this will help preserve your power as well.

I have a timer on my charger. I was planning on letting the battery charge for 2 hours on 10 amps or maybe 6 hours on 2 amps. What do you think would be best. The battery is not totally discharged it has about half of the charge left according to a meter I have. Any ideas I would be happy to hear them but please keep them simple. Thanks.
The sticker on the battery says 200 minutes @ 23 amps. I know this is the numbers that it discharges at.

Low an slow will do the "best" job. You have a good sized battery. So 10 amps is not really a high charge rate. It is hard to say how long you will need to charge the battery to get it to fully charged. Lots of variables.. Try charging for one of the amounts you are thinking of… Wait an a hour or two then check the battery. You see where you are at. Then do or don’t do what seems right to get you to the level you want. Make a note of the time an setting for future use. You just experiment till you know…

What song has a music video with car going across desert (or something like Nevada) with ufo on antenna and after bass solo was sky full of ufos. This song is rock and maybe from 1997-2000 i think, i hope, you will know it They have driven old ameican combi
and it was all about ufo

i thiiiiiiiiiiiiiiiink it may be a placebo song… or rem… ok i have no idea i just hava a kinda deja vu about this vid.. :S

In the series of Mighty Car Mods videos, there is an episode called "How to buy a Japanese car". At 11 minutes and 40 seconds into the Youtube video clip, a piece of music appears. I can’t find that particular piece of music on their website, and I’m not sure where to find it. It has the words, "all systems go" repeated a few times throughout.

The song is called ‘Dont Lick The Octopus’ by MOOG. Its currently unreleased but as many people have been asking for it, it will probably end up getting uploaded to iTunes.

You can follow the music page here for updates on music:

http://www.facebook.com/blairjoscelyne

Why is it Ferraris are rarely ever in any car video games like NFS or Midnight Club

I know they used to be in old NFS games but not any newer ones. I know Ferrari has a few games with just Ferraris, but they are rarely in games with other cars. Why is this? Does Ferrari just not give out the liscence?

the biggest issue with (ferraris in games) is that a lot of the tech behind the car is secret..not all but some.

when putting a car in to a game..the developer must first research the vehicle in question..keep in mind its not the first time a car company pulled its cars from a game or denied licensing rights..honda did the same thing just a while back (article not found) due to a concept car that was made in germany using the civics design found in [NEED FOR SPEED:underground 2]..big issues led to the removal of the cars from certain if not all games.

as for ferrari they argue that they don’t want to make the cars new tech or build public(everyone knows how secretive ferrari is about their cars) and even more having their cars damaged in a game for fear that the developers wont honor there word in minimal damage..this was the biggest problem they had with grand tourismo 5. but after all allowed sony the license to use the car.

this isn’t the case with all games..some games like NFS feature street racing and cop chases which im sure ferrari also has issues with..they have made it public that they do not encourage street racing…