ohm (resistance)

[KLA]

hi guys

regarding ohm rating, according to my studies, ohm means resistance to the current. is it low ohm better or higher ohm? i cannot work this out.

can you help to provide some examples and explain please? thanks


KL

[George M. Middius]

KLA said:

> regarding ohm rating, according to my studies, ohm means resistance to
> the current. is it low ohm better or higher ohm? i cannot work this
> out.

This is a very good question. Unfortunately, the answer is not simple.
Sometimes you want more ohms and sometimes you want less. There is a
multitude of factors to consider, some that we know of, and some as yet
undiscovered. Start with the temperature of the water as it comes from your
kitchen tap. If it's above 110F, you should adjust your ohms downward; below
80F, increase your ohmage. Also important is the color of your carpet or
rug. If it's a solid color, you definitely need to moderate your ohm
content; a pattern, such as an oriental, mandates an increase in your ohms.


> can you help to provide some examples and explain please? thanks

You might consider a mind-meld with your loudspeakers. If you have The
Talent, they will communicate their ohmage requirements. This is the
simplest approach.

[ScottW]

"KLA" > wrote in message
...
>
> hi guys
>
> regarding ohm rating, according to my studies, ohm means resistance to
> the current. is it low ohm better or higher ohm?

Assuming you mean speaker ratings... if all things equal (and thats a big
if) a higher ohm rating usually means the speaker will be easier for an amp
to drive. It will take less current at a given output level.

Usually one needs to consider the speakers efficiency as well as impedance
for fundamental amplifier compatibility.

But if you have a cheap amp... or simply don't know.... higher ohms is at
least safer for your equipment.

For most stereo amps, 4 ohm or 8 ohm speakers are fine.

ScottW

[James Lehman]

Ohms is only a measure of resistance when you are dealing with DC
electricity. When you are talking about an amplified sound signal, that is a
type of AC. Ohms within the realm of AC may be resistance or reactance or
both. In either case, DC or AC, ohms is an opposing force to the flow of
current. That much is correct. Think of it this way... Voltage is pressure
that pushes electrons through a circuit. Impedance (that's the general term
for resistance or reactance or both) is the opposing force to this pressure.
It regulates the flow of current (Amps). If you put voltage into a dead
short, (an impedance of nothing) there is no regulation of the flow and the
circuit will do its best to pass infinite current. Something that won't
happen for very long before something burns up.

Ohm's Law says that E = IR. Voltage is equal to current times resistance.
Power is P = IE. In other words watts equals amps times volts.

A stereo power amplifier usually has a fixed maximum voltage that it can put
out. That's the pressure. If your speakers have a high impedance, then you
are not going to get so much current to flow through them, resulting in less
power transferred to the speaker. On the other hand, if your speakers have a
very low impedance you might pull too much current from the amp, either
damaging the amp or causing it to distort.

The overall volume of the sound you hear from a pair of speakers has
everything to do with the efficiency of the speakers. How much of the
electrical power that is sent to them actually gets turned into sound that
you hear? All the rest of that power is turned into heat. Speakers are
horribly inefficient devices. You are lucky if 1% of the power that goes
into your speakers comes out as sound. One pair of speakers with 10 watts
going into them might sound much louder than another pair of speakers with
150 watts going into them.


"ScottW" > wrote in message
news:Iy0Ae.31634$up5.19238@lakeread02...
>
> "KLA" > wrote in message
> ...
> >
> > hi guys
> >
> > regarding ohm rating, according to my studies, ohm means resistance to
> > the current. is it low ohm better or higher ohm?
>
> Assuming you mean speaker ratings... if all things equal (and thats a big
> if) a higher ohm rating usually means the speaker will be easier for an
amp
> to drive. It will take less current at a given output level.
>
> Usually one needs to consider the speakers efficiency as well as impedance
> for fundamental amplifier compatibility.
>
> But if you have a cheap amp... or simply don't know.... higher ohms is at
> least safer for your equipment.
>
> For most stereo amps, 4 ohm or 8 ohm speakers are fine.
>
> ScottW
>
>

[Sander deWaal]

KLA > said:


>regarding ohm rating, according to my studies, ohm means resistance to
>the current. is it low ohm better or higher ohm? i cannot work this
>out.


Ohm (resistance) indeed means that, and is defined by Ohms Law V =
I*R. Where I is current, R is resistance and V is voltage (some use E
instead).
This is the most basic and important law in electronics.

But one can never say in general that high or low resistance is
"better".
Even in case of an amp with speakers, it's not a primary concern, as
long as the resistance (or impedance when we're talking about
speakers) isn't too low for the amp to handle.


>can you help to provide some examples and explain please? thanks


Do a Google on "electronics basics", there's tons of information about
that on the Internet.

--

"Audio as a serious hobby is going down the tubes."
- Howard Ferstler, 25/4/2005

[Robert Morein]

"KLA" > wrote in message
...
>
> hi guys
>
> regarding ohm rating, according to my studies, ohm means resistance to
> the current. is it low ohm better or higher ohm? i cannot work this
> out.
>
The comments are correct. However, there is a general guideline:

4 ohm speakers can work well with separate amplifiers that are large and
heavy.

8 ohm speakers are a better choice for Japanese home theater receivers. If
you use 4 ohm speakers with a typical HT receiver these, the receiver will
run hotter.

So, neither is better, but for some applications, one may be better than the
other.

[KLA]

"KLA" wrote in message
...

hi guys

regarding ohm rating, according to my studies, ohm means resistance to
the current. is it low ohm better or higher ohm? i cannot work this
out.

The comments are correct. However, there is a general guideline:

4 ohm speakers can work well with separate amplifiers that are large and
heavy.

8 ohm speakers are a better choice for Japanese home theater receivers. If
you use 4 ohm speakers with a typical HT receiver these, the receiver will
run hotter.

So, neither is better, but for some applications, one may be better than the
other.


thanks guys, very good theory and examples.

ok, i might like to put this into my case, i m going to buy an amplifier Yamaha RX-V357, this is a 5.1 receiver with 100 RMS x 5, 6 ohms. i will also be thinking to buy this set of JBL speaker SCS 200.5, 8 ohms with 160 rms peak and 40 rms continous. so, 6 ohms amplifier to boot 8 ohms speakers, does it mean the speakers will not pull much current from the amplifier than any speaker has lower than 8 ohms speakers, and hence, the amplifier will not burn out easily? what is the role of the ohms in amplifier in this case? does it resist an current from any source?

if i were to have a 8 ohms amplifer to match with 8 ohms speakers, will it perform better in electrical sense?

cheers
KL

[Arny Krueger]

"KLA" > wrote in message

>
> ok, i might like to put this into my case, i m going to
buy an
> amplifier Yamaha RX-V357, this is a 5.1 receiver with 100
RMS
> x 5, 6 ohms. i will also be thinking to buy this set of
JBL
> speaker SCS 200.5, 8 ohms with 160 rms peak and 40 rms
> continous. so, 6 ohms amplifier to boot 8 ohms speakers,
does
> it mean the speakers will not pull much current from the
> amplifier than any speaker has lower than 8 ohms speakers,
and
> hence, the amplifier will not burn out easily?

True, but frankly, if you're worried about burning out your
receiver, you're in the wrong game.

> what is the role of the ohms in amplifier in this case?

They are saying that the amp will drive a speaker rated at 6
ohms or more, within specs.


> if i were to have a 8 ohms amplifer to match with 8 ohms
> speakers, will it perform better in electrical sense?

No.

[Robert Morein]

"KLA" > wrote in message
...
>
> Robert Morein Wrote:
> > "KLA" wrote in message
[snip]
>
> thanks guys, very good theory and examples.
>
> ok, i might like to put this into my case, i m going to buy an
> amplifier Yamaha RX-V357, this is a 5.1 receiver with 100 RMS x 5, 6
> ohms. i will also be thinking to buy this set of JBL speaker SCS 200.5,
> 8 ohms with 160 rms peak and 40 rms continous. so, 6 ohms amplifier to
> boot 8 ohms speakers, does it mean the speakers will not pull much
> current from the amplifier than any speaker has lower than 8 ohms
> speakers, and hence, the amplifier will not burn out easily? what is
> the role of the ohms in amplifier in this case? does it resist an
> current from any source?
>
> if i were to have a 8 ohms amplifer to match with 8 ohms speakers, will
> it perform better in electrical sense?
>
No, the numbers cannot be used in such a straightforward fashion.

The combination above will work very well. Don't worry anymore about it.

[George Middius]

Robert Morein said:

>> if i were to have a 8 ohms amplifer to match with 8 ohms speakers, will
>> it perform better in electrical sense?

>No, the numbers cannot be used in such a straightforward fashion.

If he gives away some of his ohms, he's likely to torpedo his amplifier. Why
aren't you warning him of this dire scenario?

>The combination above will work very well. Don't worry anymore about it.

Good advice. It's similar to what I'd tell Arnii Krooborg regarding punctuation:
"It's too complicated for you so just don't use any of it ever at all. LOtS!"

[Robert Morein]

"George Middius" > wrote in message
...
>
>
> Robert Morein said:
>
> >> if i were to have a 8 ohms amplifer to match with 8 ohms speakers, will
> >> it perform better in electrical sense?
>
> >No, the numbers cannot be used in such a straightforward fashion.
>
> If he gives away some of his ohms, he's likely to torpedo his amplifier.
Why
> aren't you warning him of this dire scenario?
>
Gentle, gentle.


> >The combination above will work very well. Don't worry anymore about it.
>
> Good advice. It's similar to what I'd tell Arnii Krooborg regarding
punctuation:
> "It's too complicated for you so just don't use any of it ever at all.
LOtS!"
>
KLA, George is right. The bottom line is, if your ohms are too low, the
amplifier of a HT receiver may be damaged.
If the ohms are "too high", nothing really bad happens.