Guidance/info on these speakers/woofers?

[Reli]

Amp output definitely increases with lower ohm speakers. You can see this in the datasheets for any amplifier. They tell you how many watts it can deliver at specific ohm levels, voltage levels, and distortion levels. Lower ohm = more watts, all other conditions held equal. But the amp needs to be rated to handle it. Going below the rated ohm range for that amp might over-stress it.

 

[floyd]

Therefore if you use a larger ohm speaker, your amp may or may not be able to handle it. If you were using a lower ohm speaker I would think you are in the clear.

This is something I learnt in physics in College...but didn't fully pay attention...so hopefully others can chime in and clarify / confirm.

This is incorrect. A higher numerical impedance load is less stressful on an amplifier than a lower numerical impedance load. So it is safer to stick with 4-ohm drivers opposed to 2.8 ohm drivers.

It suprises me how many get it wrong. Not to mention confusing Output power with Music power. The output power of the amp stays the same however you can increase music power by lowering the resistance.

That's simply not true.
Increasing the resistance causes the amplifier to increase output but it also increases strain on the amplifier circuit's.
Decreasing the resistance decreases the amplifiers output.

Just remember the lower the impedance of the speaker the more strain it puts on the amplifier. For example a 4 ohm woofer puts twice the load on an amplifier as an 8 ohm woofer

A simple scientific fact lowering the impedance increases the load on the amplifier.

The lower the impedance the more the resistance.

 

[Superduper]

Floyd, lower impedance = lower resistance &
higher impedance = higher resistance.

To impede is to resist.

Amplifiers can usually pass enough power to fry themselves to a smoldering heap. The heat sink is there to absorb the heat from the output devices & release it but there is a limit to how quickly it can do this. Heatsinks are rated in how much power they can dissipate. If an amp “chip” is rated at capable of handling 4 ohm load, but a smaller heatsink is used instead, it might be that the system is intended for a 8 ohm system. Operating it with a 4 ohm load in that situation, even though the amp chip itself is 4 ohm capable could burn out because it won’t be able to dissipate heat fast enough.

 

[floyd]

I know that Norm what I meant to say the lower the number the more the impedance I know that to impede is to resist but a 4 ohm woofer has more resistance than an 8 ohm woofer it's one of those formula things . you misrepresent one number the s*** don't work on paper.

3 x 12 ohm woofers wired in parallel =4 ohms load.
3X 8 ohm woofers wired in parallel = 2 ohm load.
3 X 4 ohm woofers wired in parallel= 1 ohm load.

 

[Superduper]

Floyd, you got the general idea that the higher the amplifier output, the greater the strain on the amp, mostly due to the fact additional amplifier output generates additional heat and reduces amplifier stability. At a certain point, the heat produced by the amplifier exceeds the heatsinks ability to remove and dissipate the heat from the amp and could go up in smoke. Furthermore, the heat/cool cycles are more extreme which reduces amplifier life.

You also understand that running multiple drivers in parallel lowers the ohms load. Your computations are close although 3x 8-ohm woofers in parallel = 2-2/3 ohms and 3x 4-ohm woofers in parallel = 1-1/3 Ω.

However, the Ω is a unit of measure of resistance. Therefore, higher numerical Ω = higher resistance. IF 1 Ω = 1-unit of measure of resistance. Accordingly, 2 Ω = 2x resistance. Therefore, higher Ω = higher resistance.

On speakers, we generally don't use resistance which is a DC measurement. Instead we use Impedance which is used with AC (music). Impedance IS resistance coupled with reactance. Impedance = (resistance + reactance). So if resistance increases in that formula, then impedance will also increase. This is the reason why speaker drivers when measured with a meter almost never coincides with it's impedance spec., almost always lower (an 8-ohm impedance driver could measure 6.8 ohms resistance). That's because we are measuring DC resistance of the coil which is not the speakers impedance.

Now, it would seem natural that a higher resistive load should increase strain on an amplifier since it would have to work harder on a higher resistive load right? But an amplifier doesn't work like you or I and get tired or fatigued. Instead, it's all a mathematical computation and increasing impedance simply ends up reducing the amplifier output, which means less current passes through it, so it does not heat up as much. Lowering the impedance means current has an easier time passing through the amp and this increase in power is what causes high heat and therefore strain on an amplifier. It's not strain like you or I lifting a sack of potatoes.

I think where some confusion comes is that 3 speakers combined, each possessing a certain amount resistance, might seem like the total resistance therefore increases. And this certainly is true in a series connection. But in a parallel resistance arrangement, I think the following analogy might be better: think if the speakers impedance is represented by hoses. If you blow through one, there is some resistance. But if you put 3 of them in your lips and blow through all three at once, you will observe far less resistance because the "air charge" has 3 alternate paths it can travel. On the other hand, if you connect the hoses end to end, the blow effort will increase. Therefore, in parallel, resistance is lower and if resistance in series is always higher -- either form of connection can be predictably calculated via a mathematical formula.

 

[floyd]

You're right Norm there's a lot more to it than just simple numbers me I know all these things I just have a hard time explaining them. I also understand that an ohm rating is generalized and you have to test the woofer to see what the actual impedance is. I also understand that with speakers it's more load than resistance.

 

[BassHead]

Well. I don't believe any of you!

 

[hopey]

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Therefore if you use a larger ohm speaker, your amp may or may not be able to handle it. If you were using a lower ohm speaker I would think you are in the clear.This is something I learnt in physics in College...but didn't fully pay attention...so hopefully others can chime in and clarify / confirm.

This is incorrect. A higher numerical impedance load is less stressful on an amplifier than a lower numerical impedance load. So it is safer to stick with 4-ohm drivers opposed to 2.8 ohm drivers.

It suprises me how many get it wrong. Not to mention confusing Output power with Music power. The output power of the amp stays the same however you can increase music power by lowering the resistance.
Incorrect.




Hi Jimmy I know we have had this debate before but I am correct. All the banter above is all hypothetical.

It just Ohms Law plan and simple. The Power output of and amplifier is fixed. When you reduce the Impedance from 8 to 4 ohms you effectively gain full Amplifier output at half volume, which on 8 ohms load would be the same as full volume. So when you go past half volume on 4 ohms load your amp chip burns up due to poor voltage regulation.

 

[Superduper]

I have resisted calling out Hopey for a very long time now. Even when he dangerously stated, in a matter of fact manner that the ground in an AC system is connected to the secondary side of a transformer and has no relation to the primary side, I didn’t say much. Such a claim is preposterous and completely untrue. All he needs to do to confirm this is to touch the hot conductor of an AC transformer primary with one hand and touch the ground conductor with his other free hand, he will be immediately enlightened. On the other hand, he can touch any conductor on the secondary side of transformer winding and likewise touch the ground (earth) wire, and he might begin to understand.

Sometimes, I’m unsure if he is trying to be facetious or really believes what he is saying because I find it hard to believe that he could get things so very wrong. He is either really really wrong, or I have been a total idiot my whole life for getting everything so very wrong.

So tonight, I have blocked Hopey. That way, I no longer have to see his posts, and won’t have to get all worked up anymore. I also happen to like being an idiot and wish to remain as such, so there will no longer be any danger of being enlightened and ruining my idiotic state of being through accidentally seeing your posts. But in reality, mostly because I don’t want to throw my newly acquired and very expensive iPhone X across the room when I see those utterly absurd posts.

And Mr. Hopey, please block me too. There is no need for you to see any of my idiotic and completely wrong opinions. But mostly, please block me because I don’t wish for you to accidentally reply and quote any of my posts, nor accidentally view any threads that I’ve started. You go right on and continue advising new members to ruin their boomboxes or put themselves in dangerous situations with your “I am right” but “can’t be more wrong” posts.