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can some help me pemanantly fix my speaker system?

i have this surround sound speakers i made my self and they are great but when they break i cant even listen to music. i can usually fix them my self but they never stay fixed and they just broke again. so i have tons of speakers all differant kinds and they all have differant color wire which makes connecting them difficult. they have work just fine (while working) but now the rear channel has no sound also the second set of speakers have a buzz( like on a guitar amp) when so sound is playing through
can someone please help me with this



ok so we have all realized that ive blown my left channell amp on the second speaker but what about the first?
if you look at the diagram one is connected to the other
i have tried to put just 1 speaker to the first amp but no sound comes out (the speaker has been tested and its not blown) 
why is this and can i get another speaker to work with it

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gmoon7 years ago
If they worked at one time, what did you change?

Re: understanding impedance.

Impedance is essentially AC resistance . With AC signals, other components besides resistors (inductors and capacitors, for instance) have resistive properties. Those properties change with the signal frequency (that's why AC resistance is different than DC resistance.)

The water pipe analogy is fine, but we're overlooking the difference between input impedance and output impedance . In aspects, they effect the signal in opposite ways.

See the simple (oversimplified) picture below...

-- the signal source is the left circle
-- Output impedance (of the signal source) is Zs
-- Input impedance (of the next device) is ZL. This is also termed the "Load"

In normal operation, you can think in this way:

Output impedance (Zs) is resistance that gets in the way of the signal coming through. Essentially like a resistor connected in series.

Input Impedance (ZL) is resistance that acts as a drain during the transfer between the two stages (the left stage feeding the right stage.) I.E., it's kinda like a resistor connected to ground.

The right "stage" could be a speaker, or it could be a mixer or an amplifier.

There's a general rule of thumb:
The input impedance (the right side of the picture) should be approx ten times the output impedance of the preceding stage (left side.) That's a 1:10 ratio, output to input impedance.

So a high input impedance puts a very small load on the signal, but a high output impedance puts a very large load on the signal.

If you connect a very larger resistor (1 Meg, for instance) in series (output Z), it's going to stop a LOT of the current from getting through.

If you connect the same resistor (1 Meg) in parallel to the ground, it's going to draw very LITTLE current away from the signal.

So in a way, they work as opposites...

---------------

Why you shouldn't connect different output signals without a mixer:

A speaker-driving stage (an amplifier) will have a very LOW output impedance--for instance, a amp that drives an 8 ohm speaker (that's the speakers input impedance) usually has an output impedance less than 1 ohm. That means that there is very little AC resistance to that signal coming through.

But a line-driving stage will have a much higher output impedance--maybe 500 ohms. It doesn't need as much current to drive a line input, with a input impedance of maybe 10000 ohms.

This can be very BAD for both the outputs--neither is getting the type of load it needs, so either or both can be fried...
impedance.jpg
fastcar123 (author)  gmoon7 years ago
so your sayiong all i have to do is put a very large resistor on the ground wire of the in put signal (the wire comeing from the first amp speaker to the second amp speaker and that will not only return sound to my other speakers but will reduce the buzz?
Um, not really. Actually, I'm not really understanding your question...

The Zs and ZL in the diagrams don't show actual resistors, they show the "effective AC resistance" of output and input impedance, respectively. I.E., that's how the existing circuits react electrically.

You can increase impedance. For instance, the output impedance for a speaker-driving amplifier--with a resistor, or a voltage divider. That probably will help prevent it from destroying any line outputs you connect to it.

But the signal strengths will still not be the same, because they were designed to do different things (as in: "not compatible".) If you increase the output impedance enough so it's closer "impedance-wise" to the line output, then it will not drive a speaker anymore. Doing so attenuates the signal (which is good, if it prevents damage to the line out.)

The most common cause of audio "buzz" is ground loops. See the pic.
qac2studioinst4_l.jpg
fastcar123 (author)  gmoon7 years ago
so i need to divide the volage not the current right? and a simple resistor does not just divide voltage but also current as well
 
and what i should do is disconnect ground all together to stop the buzz?
that dosent sound right maybe i misunderstood the diagram
A voltage divider will divide current, too (this is somewhat dependent on the load.)

Seems to me you're still missing the point (of most of these discussions):

It's a very BAD idea to attempt to mix power signals (the types of signals that amplifiers produce.) And to try to mix them together with line output signals (voltage amplifiers.) Its bad for multiple reasons:

-- All mixers create attenuation -- they lose signal strength. Active mixers have additional stages to recover the signal strength. It's a very efficient process at low voltage, low current levels.

-- High-current (wattage) signals need large, expensive resistors as attenuators. And in reducing the signal, all that wattage is simply wasted as heat. And then another power amp is needed to bring them back up to the original state.

-- High-current amplifiers are designed to drive inductive loads (speakers), not resistive loads (such as a resistive voltage divider or L-pad attenuator.) They don't sound nearly as good through resistors.

So It makes NO sense to create a high-current (wattage) signal, simply to chop the wattage down to a point where it can be mixed with a low-current line output.

Mix all your signals together at line levels--then feed that into a power amp. Don't amplify them first, it's a complete waste of the amplification.
gmoon gmoon7 years ago
Did you read the link about ground loops, rather than just looking at the pic?
fastcar123 (author)  gmoon7 years ago
yes
fastcar123 (author)  fastcar1237 years ago
ive read the and would the position of my amp have anything to do woth the buzz/hum?
the speaker sets between a tube tv an lcd monitor a modem a wireless router a pc a radio and a stand alone subwoofer (not the one included in the pic)
fastcar123 (author)  gmoon7 years ago
so you are aying instead of connecting theamp in seris as ive done her i should just plug them both into the computer and operate the volume controls on both manualy
cvianna17 years ago
Do you know if your speakers correctly match the output impedance of your amplifier? If not you may end up overloading your amp and burning it out.

It also looks like you are amplifying your signal twice from this diagram, any distortion in the signal would also be amplified twice which could cause the buzz or it may be that due to an impedance mismatch and you're over-driving your amp and causing distortion and burning out your channels.

The lower the the impedance of the devices connected to your amps the more power needed to drive them. Check to make sure your amps can handle the load that they're connected to.
fastcar123 (author)  cvianna17 years ago

im not too famillier with impedace but what i can tell you is that none of them have any resiters and that they all have differant voltage and amp levels

Impedance is usually measured in Ohms and is related to resistance but it is not quite the same. Think of a pipe and water flowing through it. A really wide pipe has low impedance and power/water flows at a high rate and it takes a really big pump/amp to fill it and push the signal through.

A narrow pipe / higher impedance would give more resistance and restrict the flow of water/signal. A smaller pump could maintain the pressure needed to push the signal through. 

If you have an under powered pump/amp and you have all kinds of different pipe diameters, most likely the amp can't deliver the correct power needed to drive your speakers. Another thing about impedance is that it also changes with frequency, so different signal frequencies will cause changes in output impedance.

Most amps have their impedance requirements written on the back. So do a lot of speakers. You also have to note whether your speakers are hooked up in parallel, or in series as this also has a huge effect on the amount of power needed to drive them. I'm not sure but you may be able to purchase an impedance matcher for the output of your amp.
fastcar123 (author)  cvianna17 years ago
ok so higher impedance the smaller the amp can be right?
they are in parrallel
i dont think they say any thing about impeadance on the back ( if im wrong tell me) because they are just a bunch of random computer speakers intigraded into one set so they are pretty primative 
If you can't  find the impedance written on the back of the speakers, you may be able to look it up online by the speakers part number. You also need to know what your amp is rated and may be able to look that up as well. Parallel hook up is the safest. Serial setups can get tricky and shouldn't be done if there is any other way.

fastcar123 (author)  cvianna17 years ago
serialis what i have right?
what do you mean by amp rateings?
By amp I am referring to your amplifier. Series connection means items hooked up in line one after another :

-----(+) speaker1(-) -------- (+)speaker2(-) --------(+) speaker3(-) --------

Parallel + and - connected to the same place:

(+) ------speaker1(-) --------
(+) ------speaker2(-) --------
(+) ------speaker3(-) --------
fastcar123 (author)  cvianna17 years ago
well yea im running in paralell
I wish I could be more help. But without the specs for your system I don't know what else to advise other than going to an av store and seeing if they can tell you what your specs are.
I can't offer much more than the others here, but the buzz you described sounds like distortion to me.  Distortion in this case may occur if the signal from the receiver is already amplified to drive a speaker but is being amplified again by the setup you built.  If this is the case, there are several ways to prevent this but each way depends entirely on the types of speakers in each enclosure, how many watts they're rated for (and how many watts the receiver is outputting to them), whether they require crossovers, &c.
fastcar123 (author)  MahavishnuMan7 years ago
i dont know about that but your idea makes sense what is strange to me is that it worked fine in january then stared buzzing
frollard7 years ago
Why do you have so many different powered speakers on so many different supplies?

Wouldn't it make more sense to get an amplifier and do a home-run wire from each speaker to the base?
fastcar123 (author)  frollard7 years ago
actually i picked up thes speakers from differant places as differant sets

and wat i was triing to do was put an amp on the rear and an amp on the front and have the front as a master controller but the front right speaker stopped working due to the fronts faulty out jack 
I have no idea what to suggest then - other than run them all on the same amp design with the same voltage.
fastcar123 (author)  frollard7 years ago
humm yes its very strange
fastcar123 (author)  fastcar1237 years ago
how about the buzz would you know about that
.  If it's 50/60 Hz hum, then I'd look for a faulty filter capacitor on a power supply and/or a bad ground.
fastcar123 (author)  NachoMahma7 years ago
how could i tell what level of Hz the humm might be at?