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Why do mfg make 4 ohm speakers


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#1 of 29 Rajeev_s

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Posted February 04 2004 - 01:52 AM

I am confused as to why some speaker manufacturers make 4 ohm or lower speakers when there are not many mid priced receivers that can power them. And there are speakers with similar performance that other speaker manufacturers make that are 8 ohms. So why the need for 4 ohm speakers, can they not just get the similar performance out of 8 ohm ones ?

#2 of 29 John S

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Posted February 04 2004 - 04:03 AM

4 ohm speakers should only be used mostly with higher end stuff. Like with separates which extrenal power amps that usually just love and eat up 4 ohm loads.

Yamaha NS series speakers tend to be 6 ohms which is great for most midline AVR's and allow them to put out more power.

Just my 2 cents on it anyways.

#3 of 29 Rajeev_s

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Posted February 04 2004 - 08:13 AM

Thanks John. Any other views guys ?

#4 of 29 John S

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Posted February 04 2004 - 08:43 AM

There was a similar thread somewhere, and it does seem many receivers even mid-fi level do offer 4 ohm speaker use.


The sited JVC units as even having a switch on the back for 4 ohm loads.

#5 of 29 RyanH

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Posted February 04 2004 - 08:44 AM

With headphones (my specialty) resistance will vary anywhere from 8 ohms to 1000 ohms. It really has to do with the design goals and what the driver is intented to do and work with. Some speakers are designed to be placed with lower end components... while others are designed to be placed with higher end components. But there are many scientific reasonings behind why a speaker would be designed with more resistance, requiring more power and less current. Im no amp/speaker designer so I really cannot elaborate on why..sorry!

#6 of 29 Ray_C

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Posted February 04 2004 - 09:02 AM

I would think that most quality amplifiers want to open up a bit to sound their best. With an efficient 8-ohm speaker, at comfortasble listening levels, your probably only putting out about 8-20 watts or so, which is like whispering for an honestly-rated 100+ watt amp. I think there's more overall dynamics and richness when an amp begins to get driven, at least until you start approaching the upper limits of its range when strain and distortion set in (especially nasty with solid-state amps....but us guitarists with tube amps live for this). This is probably the reason why some amps are classified as 'Class A' operation at lower output levels, so that the amp is running hot to begin with, then switches to 'Class AB' as you get louder, applying the power appropriately for quick bursts. So when you think about it, if you have a separate quality 125-watt amp, a four-ohm load would probably make it pretty happy. I have Klipsch reference speakers, and I think they're too efficient (at 8 ohms and eff. in the mid 90 dB's!) for my Marantz MM9000 amp. I'd like to get the amp to get going a bit more without tearing down the walls.

#7 of 29 Joe Casey

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Posted February 04 2004 - 09:34 AM

Speaker impedance ratings (ohms) have nothing to do with how loud they'll play for a given amount of power. A speakers efficiency rating dictates that characteristic. Impedance ratings are included to offer an idea of how difficult a load the speakers are as far as the amp is concerned. Plugging a 4 ohm speaker into an amp rated at 8 ohms and above will fry the amp at louder levels, as it cannot handle the current demands of the lower impedance speaker.
Q

#8 of 29 Luitz

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Posted February 04 2004 - 09:38 AM

Excluding the tweeter this generally applys
Most manufactures that make a speaker with 2 4inch or bigger drivers will use 2 4ohm drivers to attain a 8ohm load. Almost all the time. Sometimes when they use 3 to 4 drivers they might use 2ohm drivers each to attain a 6 to 8 ohm load.
If a amplifier makes 50 watts into 8 ohms in 6 ohms it should produce alittle more power although it will produce more heat as well. Also a amplifier that can run 4 ohms is gererally of higher end nature.Posted Image

Think of yer garden hose when running water say its 8ohms. As u kink the hose the pressure builds up and pushes the water farther thus more power untill its stops which would be a short. You get it???

#9 of 29 ChrisWiggles

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Posted February 04 2004 - 09:51 AM

Think of yer garden hose when running water say its 8ohms. As u kink the hose the pressure builds up and pushes the water farther thus more power untill its stops which would be a short. You get it???


You've got it backwards. A more kinked hose would be 8 ohms. Unkinking it a bit more would be 4 ohms, and would allow a larger volume of water (electricity) to flow through. No resistance (i.e. no kink) is a short.

As for why 4ohm? Perhaps in that design and configuration things sound better.

#10 of 29 RyanH

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Posted February 04 2004 - 10:22 AM

Hmm, no i think you have it backwards. A more kinked hose would cause more resistance. The lower the ohms, the higher the resistance. Hence more power is needed to "push through" the resistance (the kink)(the ohms). Hence the output (psi?) is higher.

#11 of 29 John S

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Posted February 04 2004 - 10:26 AM

No RyanH, the lower the OHMs the lower the resistance.

You have it backwards..

Basic OHMs law at work here.... lol

#12 of 29 RyanH

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Posted February 04 2004 - 10:32 AM

oh yeah sorry... I get ahead of myself sometimes.

#13 of 29 ChrisWiggles

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Posted February 04 2004 - 10:35 AM

Posted Image

#14 of 29 ken nomimashita

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Posted February 04 2004 - 10:35 AM

4 ohms is a good resistance for the kind of amplifiers that are used for most home audio stuff. BTW on most amps that arent peices of crap you can run them under impedence for a little while, they will just get hotter.

#15 of 29 John Garcia

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Posted February 04 2004 - 10:54 AM

Quote:
Plugging a 4 ohm speaker into an amp rated at 8 ohms and above will fry the amp at louder levels, as it cannot handle the current demands of the lower impedance speaker.

When you run out of current, you will fry speakers before you fry amps.
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#16 of 29 Luitz

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Posted February 04 2004 - 11:07 AM

DOh :b

See even I made a mistake
And why I edit so many dam times on a post..lmao

Here read this
http://www.carvin.co.../drsound04.html

#17 of 29 Robert Cowan

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Posted February 04 2004 - 03:33 PM

i dont know if its been mentioned before, but lower impedence speakers are also sometimes just that way because of design. planars and electrostats are sometimes VERY low (less than 1 ohm for some of the apogees), because they have almost no resistance (no moving cones). these of course need pretty decent gear to drive them, and are not made for lower end stuff.

#18 of 29 LanceJ

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Posted February 04 2004 - 07:55 PM

A looooong ago time in an era called The Early 80s Posted Image when Acoustic Research, Infinity and other manufacturers still built acoustic-suspension speakers, lots of those manufacturers purposely designed their speakers to present a 4 or 6 ohm load to the amplifier. Why? Because of their design, acoustic-suspension (i.e. sealed) speakers are more inefficient than certain other systems. So, the 4/6ohm "feature" was used to help make up for this by allowing the driving amplifier to generate more power.

But as others have mentioned, for some cheesy amps this can cause problems. But then again, generally speaking amps back then weren't quite as cheesy as many are nowadays so this wasn't a big issue.

LJ

#19 of 29 cabreau

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Posted February 05 2004 - 12:07 AM

So tell me...why, when you put two 8 Ohm speakers together in a parallel?/serial? configuration, doesn't it ADD the resistance together to make a 16 Ohm resistance? I understand that less Ohms is less resistance, therefore LETTING more current flow through and frying the amp. What I can't understand is why when you add two speakers together, it lowers the resistance.
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#20 of 29 John F. Palacio

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Posted February 05 2004 - 01:04 AM

Quote:
So tell me...why, when you put two 8 Ohm speakers together in a parallel?/serial? configuration, doesn't it ADD the resistance together to make a 16 Ohm resistance? I understand that less Ohms is less resistance, therefore LETTING more current flow through and frying the amp. What I can't understand is why when you add two speakers together, it lowers the resistance.


If you wire two speakers in parallel you will LOWER the impedance. If you wire them in series you will RAISE the impedance.

Two 8 ohm speakers in series will present a 16 ohm load, whereas two 8 ohm speakers in parallel will present a 4 ohm load.

Ohm is a measure of resistance. Or more acurately impedance, in the case of a speaker, because it has inductive and capacitive components and will vary with frequency. As such; The higher the ohms the more resistance.
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