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test of speaker....

M

mainmansam

New Member
This may be a really stupid question but here goes....If I test a 16 ohm speaker with a direct lead from my reciever for an 8 ohm speaker do I risk blowing it out? If so, is there a safe way to test this 16 ohm speaker? Thanks in advance
 
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it's only dangerous if it's a tube amp w/ output transformers. solid state amps should typically do fine with a 16 ohm load.
 
very novice to electricity with a multi-task voltmeter, am I to gather that a 16 ohm speaker since has twice the ohm rating should need twice as much wattage to operate than my 8 ohm speaker? There is a crossover and I'm wanting to make sure the wires frfom it go to the correct speakers in the cabinet.
 
Ohm's are a very confusing thing, or at least I have always thought so. What makes it confusing is the value (number) of the ohms really relates to power needed (lower value, means more flow of power), and is not really a measure of unit resistance (in value) as one would think. As I understand it, a lower ohm value means that more current is needed to drive the speaker and conversely, a higher value means less power is needed. One would logically think that, numerically, it would be the opposite (i.e. higher ohms means higher resistance, thus higher current is needed). The concept of ohms (in terms of numeric value) is not consistent with watts, volts and amperes, where a higher number means MORE of something. I think the reason for this is the fact that it is all based on mathematical formulae.

Another strange thing is wire gauges, where the higher the gauge, the thinner the wire, which is also VERY bizarre. One would think they would have used a more intuitive measuring standard for wire gauges, but instead they measure it by manufacturing methods. The number of 'drawing' operations needed to reduce the size of the wire is where numeric gauge values come from.

Based on what I have read, the whole area of electrical engineering is littered with illogical paradigms, in that they don't follow a natural 'common sense' approach.
 
thanks......now I'll search out the idea behind crossovers and if I can't find the answers I'm looking for I'll ask. I like to read all I can first then formulate questions. what a great site for information this is
 
As I have always understood it, a lower ohm rating on a speaker puts less of a load on the amp. With less of a load an amp is more likely to overdrive itself, like running a car motor to too high a rev too easily when the transmission is out of gear. A 16 ohm load will keep the amp from operating at it's full wattage output because it will start to clip, which is why you have to be more careful with high ohm loads. It would be like the car motor in gear but hauling an extra heavy trailer. The extra weight is not a problem but you don't want to push it too hard.

If this analogy is way off base I, for one, would like to know.
 
King bubba, good analogy.

I like to use this one, someone could poke holes in it but here it goes--

Think of a pulley and rope. As you pull one end, then the other, back and forth, this is your "AC". The impedance (resistive) is like putting a disc brake on the pulley, "impeding" the rotation back and forth. The braking power is less at 16 ohms than 8 ohms, thus less heat, less power applied.

A short circuit would be a brake disc and pads that are "frozen"

A very simpleton explaination.

A "warped disc rotor" would be a speaker with terrible linearity.
 
MaxSeven said:
One would logically think that, numerically, it would be the opposite (i.e. higher ohms means higher resistance, thus higher current is needed). The concept of ohms (in terms of numeric value) is not consistent with watts, volts and amperes, where a higher number means MORE of something. I think the reason for this is the fact that it is all based on mathematical formulae.
Click to expand...

You're just thinking about it backwards. The current in question isn't what is "needed" but what is "allowed". Higher resistance will let less current flow.

Think of a hose. If you crimp it, but not completely, you've created a higher resistance and less water will be able to flow through it, i.e. less current. That help?

Ray
 
BillR mastering said:
The braking power is less at 16 ohms than 8 ohms, thus less heat, less power applied.
Click to expand...

That is the quintessential sentence that shows why ohms are such a confounding concept. Most anywhere in life, when you have a larger number, it means 'more' of something and not 'less'. Where in this analogy, a braking power of 16 is actually less braking power than 8.
 
RayW said:
You're just thinking about it backwards. The current in question isn't what is "needed" but what is "allowed". Higher resistance will let less current flow.

Think of a hose. If you crimp it, but not completely, you've created a higher resistance and less water will be able to flow through it, i.e. less current. That help?

Ray
Click to expand...

I'm referring to the numerical logic, not the mechanics of it.
 
RayW said:
So am I. If there is more resistance then less current will be allowed to flow. That's logical.

Ray
Click to expand...

I agree with you, but the number (i.e. 8 ohms) should correspond to the resistance, not the current. And since an ohm, by definition, is a measure of impedance, there seems to be a disconnection between the number and the term.
 
MaxSeven said:
Ohm's are a very confusing thing, or at least I have always thought so. What makes it confusing is the value (number) of the ohms really relates to power needed (lower value, means more flow of power), and is not really a measure of unit resistance (in value) as one would think. As I understand it, a lower ohm value means that more current is needed to drive the speaker and conversely, a higher value means less power is needed. One would logically think that, numerically, it would be the opposite (i.e. higher ohms means higher resistance, thus higher current is needed). The concept of ohms (in terms of numeric value) is not consistent with watts, volts and amperes, where a higher number means MORE of something. I think the reason for this is the fact that it is all based on mathematical formulae.
Click to expand...

umm, that'd be Ohm's Law, which is pretty simple: E = I x R
(volatage = current times resistance)

Virtually all of DC circuit design flows from Ohm's law -- which also applies to things like water flowing through garden hoses!

Actually, since impedance (the AC analog of resistance) also obeys Ohm's Law, most AC theory flows from Ohm's Law, too.

EDIT: The only other thing you need to know is P = E x I (power = voltage times current). Substituting "E" from Ohm's law readily gives you: P = I^2 x R (power = [current squared] times resistance). This is, for example, the equation of 'resistive heating', or "I^2R heating", which governs how much juice your toaster's NiChrome heating wires will draw out of the wall.
 
I=E/R

Consider E constant

Amps are constant voltage (E) devices.

Well, not actually, but for the sake of understanding.

With voltage constant, current (I) and impedance (resistance, R) are related reciprocally.

Put a 16-Ohm speaker on the same amp as an 8-Ohm one, and, at the same volume (voltage) setting, it will draw half as much current, and produce half the power output.

Y'all need to study up Ohm's Law to figure this stuff.... :yes:
 
My simpleton explaination is just that, simple. Of course we could get into Qms, Qes, Qts, Back Emf, Baffle effects, room effects (yes, how you load your speaker system into the room can and will change the impedance curve)..and so forth. Dynamic speakers by virtue of physics do not maintain a flat impedance VS Fq as well...

Basically, if your amplifier is safe at a nominal 8 ohm impedance, it is "more than safe" at 16..but less maximum output power is the result. (not to include transformer output devices,/most tube amps)..then we can get to OTL.... ( I better not.. :) )
 
MaxSeven said:
I agree with you, but the number (i.e. 8 ohms) should correspond to the resistance, not the current. And since an ohm, by definition, is a measure of impedance, there seems to be a disconnection between the number and the term.
Click to expand...

I guess I'm still not seeing your reasoning. As impedance goes up the number (ohms) goes up. As impedance in a constant voltage circuit goes up, current goes down. Go back to the hose analogy. If you increase the resistance, squeeze the hose tigher, then less water flows, i.e. less current. Where is the numerical disconnect? I'm really trying to understand where you're coming from, not trying to be a jerk.

Ray
 
Sorry but there is some misinformation that has been posted earlier on the first page of this thread.

The LOWER the resistance--the lower the "Ohms"--the MORE load (current) is put on the amp. Why? The SS amp is (usually) a constant voltage source (Zilch is exactly correct). And V=IR. For a constant V, if you lower R, then I must increase. (I believe there's a "sticky" that also explains this under the Vintage Solid State forum.)

The "braking pulley" analogy wasn't applied properly to this. The analogy would kinda work if you hung a weight over a pulley, though, and let the weight fall with only the braking action of the pulley to slow it down. For a constant weight, if you increase the braking action (resistance), the weight would fall slower (less current flow). Decrease the brake (resistance), the weight falls faster (more current flow). (Yes I know speed isn't *really* equivalent to current, I'm just showing the proportional effect)

Bottom line, for most solid state amps--transformerless designs--if you can run with an 8 ohm load, you can run with a 16 ohm load without fear. The opposite is not necessarily true: some amps can run 8 ohm loads but cannot deliver enough current to run a 4 ohm load.
 
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