Are 4 Ohms Speaker are better sound than 8 Ohm Speakers?

Audio_Freek

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Hi Friends,

Could someone clarify my doubts regards to 4 Ohms and 8 Ohms speakers.I heard and read that DOUBLE the power is required to drive the 4 ohms speaker by a amplifier which produced power at 8 ohms impedance.

i.e Amp with 100W RMS at 8 ohms will deliver only 50 watts with 4 ohms

Also a 8 Ohms impedance amplifier can even burn off ,while running 4 ohms speakers

1.If this true then, does there any difference in quality of the Sound produced in 4 Ohms speakers?
2.If not then why they are manufacturing such 4 Ohms speakers,which cannot be matched with all amps easily?
3.Are there any advantage of using the 4 Ohms speakers?
4.What are the specification to be noticed while searching a Stereo amp to match with 4 ohms speakers?


Thanks for your responses
 
Hi Friends,

Could someone clarify my doubts regards to 4 Ohms and 8 Ohms speakers.I heard and read that DOUBLE the power is required to drive the 4 ohms speaker by a amplifier which produced power at 8 ohms impedance.

i.e Amp with 100W RMS at 8 ohms will deliver only 50 watts with 4 ohms

Also a 8 Ohms impedance amplifier can even burn off ,while running 4 ohms speakers

1.If this true then, does there any difference in quality of the Sound produced in 4 Ohms speakers?
2.If not then why they are manufacturing such 4 Ohms speakers,which cannot be matched with all amps easily?
3.Are there any advantage of using the 4 Ohms speakers?
4.What are the specification to be noticed while searching a Stereo amp to match with 4 ohms speakers?


Thanks for your responses

There are amps that give double the power for 4 ohms, depends upon the design. 100w at 8 ohms, 200w at 4 ohms.

If a speaker presents a 4 ohm load, it needs twice the current as compared to a 8 ohm load.

sq has nothing to do with the impedance of the speaker.

there was another thread sometime ago on the same topic, check that, you might get more info there.
 
Impedance is not a fixed unit. It's a variable.

So even if your speaker is written 8 ohms, it can dip to as low as 3 ohms while playing certain tracks.

Similarly a 4ohm speaker does not all the time draw 4ohms, it may sit at 6 and dip to 3 and back to 4 or 6.

Sound quality on the other hand is something determined by other things combined as one, impedance is just one variable out of all those combined variables.
 
Hi Friends,

Could someone clarify my doubts regards to 4 Ohms and 8 Ohms speakers.I heard and read that DOUBLE the power is required to drive the 4 ohms speaker by a amplifier which produced power at 8 ohms impedance.

i.e Amp with 100W RMS at 8 ohms will deliver only 50 watts with 4 ohms

Also a 8 Ohms impedance amplifier can even burn off ,while running 4 ohms speakers

1.If this true then, does there any difference in quality of the Sound produced in 4 Ohms speakers?
2.If not then why they are manufacturing such 4 Ohms speakers,which cannot be matched with all amps easily?
3.Are there any advantage of using the 4 Ohms speakers?
4.What are the specification to be noticed while searching a Stereo amp to match with 4 ohms speakers?


Thanks for your responses

To me, there is no straight forward answer to this. Let me explain with a simple example - if I have a amplifier with abudant power, then I would simply go for a 4 ohm. The problem with the 4 ohm speakers is not with the speaker itself, but rather with the source which needs to feed the power hungry speakers. This example is in an ideal world.

In the real world scenario, one cannot always consider impedance alone to judge the performance of the speakers. The other aspect is the sensitivity. Higher the sensitivity indicates better efficency. In the real world, there exist only few amplifiers which can drive a 4 ohm. So if I get an 8 ohm speaker with higher sensitivity, then I would prefer the 8 ohm speaker for two reasons. First, the amplifier is not fully loaded. Second, with minimal power, the amplifier can drive the speakers with good sound levels.

So I can say like this - An higher ohm speaker with higher sensitivty will be as powerful (interms of sound level) as that of a lower ohm speaker. In case if you get a lesser ohm speaker with high sensitivity and a matchinh amplifier with abundant power, then that would be the greatest combination. But this combination will cost you a lot. So even if you go for a higher ohm speakers, having a very high sensitivity would be more than enough.
 
So 4 Ohm speakers could be classified for Hi end audio gear? as cost of Amp and Speakers would be more than 8 ohm set up
Ex: 100w @ 8 Ohms with amp for 8 ohms 100w at 85 db will cost low compared to
50 w @ 4 Ohms amp for 8 ohms at 85 db also the performance will be not with big difference between two.

I have seen class A or Mono Blocks well support the 4 Ohms spec( which are pretty costly than the other category like AB,D etc).

So does the Less Ohm speakers are so costly than more ohms speakers?

And what could be the "Marketing strategy" behind the 4 Ohms speakers, as they dont match with the most of the amps out in the market and the people who chose those needs to invest lot ? they could go with 8 or 6 Ohms speakers setup saving money.

though we feel Music is a passion for people, its a Business for the company and Why the produce are non-moving products.

Have anyone used 4 ohms speakers and matched with right pair ? any ideas on any modles which can drive those speakers well say for 100 W 85 DB
 
Impedance is not a fixed unit. It's a variable.

So even if your speaker is written 8 ohms, it can dip to as low as 3 ohms while playing certain tracks.

Similarly a 4ohm speaker does not all the time draw 4ohms, it may sit at 6 and dip to 3 and back to 4 or 6.

Sound quality on the other hand is something determined by other things combined as one, impedance is just one variable out of all those combined variables.
Brother you are absolutly right, any music or track would have frequencies which go low and high alternately

But am afraid that some articles says " 8ohms amp will be in danger while running 4 ohms", and certainly its not recommend to use though
 
There are amps that give double the power for 4 ohms, depends upon the design. 100w at 8 ohms, 200w at 4 ohms.

If a speaker presents a 4 ohm load, it needs twice the current as compared to a 8 ohm load.

sq has nothing to do with the impedance of the speaker.
.

So whats the use of using a high cost low-impedence speakers and Amp ,if there is no great to feel on SQ:(

So its better to be away form 4 ohms speaker set-up and enjoy with the normal 8 or 6 ohms which is comparably low cost and equal performance
 
So whats the use of using a high cost low-impedence speakers and Amp ,if there is no great to feel on SQ:(

So its better to be away form 4 ohms speaker set-up and enjoy with the normal 8 or 6 ohms which is comparably low cost and equal performance

Like I said, impedance is just one of many variables. Impedance itself does not determine the quality of a speaker or an amp. If it were so then tube amps and full range drivers would have gone the way of the dinosaur long ago.

Every combination has a certain sound signature.
 
So 4 Ohm speakers could be classified for Hi end audio gear? as cost of Amp and Speakers would be more than 8 ohm set up
Ex: 100w @ 8 Ohms with amp for 8 ohms 100w at 85 db will cost low compared to
50 w @ 4 Ohms amp for 8 ohms at 85 db also the performance will be not with big difference between two.

I have seen class A or Mono Blocks well support the 4 Ohms spec( which are pretty costly than the other category like AB,D etc).

So does the Less Ohm speakers are so costly than more ohms speakers?

And what could be the "Marketing strategy" behind the 4 Ohms speakers, as they dont match with the most of the amps out in the market and the people who chose those needs to invest lot ? they could go with 8 or 6 Ohms speakers setup saving money.

though we feel Music is a passion for people, its a Business for the company and Why the produce are non-moving products.

Have anyone used 4 ohms speakers and matched with right pair ? any ideas on any modles which can drive those speakers well say for 100 W 85 DB

Basically, the designer of a speaker does not choose the impedance. Generally, when one designs a system (any system), the design is dictated by the "requirements". In case of designing a speaker, having 4 ohm or 8 ohm impedance is not considered as part of the requirements. It is the other way where the overall impedance is dictated by the design. For example, the number of drivers and crossovers used as part of the speaker design will determine the impedance. So impedance should not be considered as a requirement.

I am not very much sure if a manufacturer advertises his speakers explictly based on the impedance rating. By their speaker design, if the impedance comes to 4 ohm, the maunfacturer will simply document it in their spec sheet. Having said that, you have asked a very valid question on what the marketing strategy could be for a 4 ohm speaker. The answer is simple - As I said before, I don't think the manufactures explicitly uses the 4 ohm rating for that. They will only advertise how powerful and efficient their speakers are. There may not be enough number of budget oriented Av receivers/amplifiers for those 4 ohm speakers, but there are still some very high end/powerful/bulky amplifiers (e.g NAD, Machintosh) which can drive those 4 ohm speakers with ease. And there is a segment of audioholics who will prefer a powerful amplifier and a 4 ohm speaker. It is like Ferrari manufacturing cars only for a small and elite segment of people. Another example is NAD where they don't sell in mass like Denon or Marantz or Yamaha, but the are people (audioholics) who look for 200% perfection in audio rather than giving importance to overall look and features. If you take a NAD amplifier, the external design won't look as great as Onkyo/Yamaha/Denon/Marantz or it won't even have the cosmetic features of other brands. Instead, it purely focuses 100% on the sound quality and there is a segment of audioholics who will prefer that.
 
Adding more to what I said - Even with 8 ohm speakers, the designer can design them with high efficiency. Like what corElement said, there are other vaiables that designer will consider for making a speaker powerful. Having said that, the designer might try to make a speaker as powerful with 8 ohms rating, but beyond a point, in the course of making the speakers still powerful, it might ultimately lead to lesser impedance.

To give a simple analogy - It is like trying a design a smaller engine (equivalent to 8 ohm speaker) efficiently and try to squeeze more power as much as possible from that small cubic capacity engine. If the engine designer wants more and more power, then he will ultimately design an engine leading to increased engine cubic capacity. The best example is the 1.3 Fiat Turbo Diesel engine running on Maruti swift and even though the engine capacity is small, it is powerful than some of the 1.4 diesel engines. Fiat has done it's best to make such a small engine highly efficient and churn out enormous power. In the pursuit of making it more powerful, Fiat hit the design limitation and that is why they designed 1.5 Turbo diesel engine (yet to be out in Indian market). Same applies to 8 ohm speaker vs 4 ohm speaker.
 
look at it this way..

a. A Speaker DRAWS current from the amplifier.

b. the amplifier DOES NOT SEND current to the speaker

c. If the speaker impedance reduces..the speaker will try to draw more current from the amp.. then the amp must be in position to deliver the higher current requested by the speaker. If not.. then clipping etc..

d. If the speaker is of high impedance.. then even a moderate power amp
( read current ) will be able to drive it. This is reverse of point c.

e. In reality.. no speaker impedance is EVER constant.. it varies with frequency. What is to be seen is the constancy of impedance over the freq range and THIS IS what decides which speaker is better than the other.

f. If speaker A provides a constant impedance over the freq spectrum evben though it may be 4 ohms.. then that will be preferred to the over where impedance varies ( though it may be rated avg 8 ohms )

Point E is where system matching comes in and this is the subjectivity of it all..

I stand ready to be chided and corrected !

;-))

regards,
mpw
 
Speaker impedance has nothing to do with quality. It depends on components used to make the speaker.

A speaker's rated impedance is the impedance seen by amplifier at 1kHz. The impedance is usually lower for lower frequencies as woofers draw more current to generate low frequencies. A speaker is a reactive load (including cross overs). So the current they draw is different from a resistive load of an equal "Ohm" value. Amplifier manufacturers understand this and state amplifier's load driving capability at lower loads. So an amplifier rated at 60W for an 8Ohm speaker may have a capacity to produce 100W at 4Ohm.

It's generally advisable to buy speakers with 8Ohm impedence, since most speakers are made with that specification. Most amplifiers are also designed for 8Ohm speakers, although they _can_ drive 4Ohm speakers.
 
@mpw, @shanmune @ coreElement,

So in other words is it always rewarding to go for a higher impedance speakers of say 8 ohms and 6 ohms, so that the AVR would be less burdened to release its power.

BTW, I am using an AVR which states in the specifications as:
130W + 130 W at 6 ohms EIAJ
75W + 75W at 8 ohms EIAJ
(20 Hz-20Khz with 0.08 % THD) for the front channel

and my tower speaker's impedance is rated 6 ohms and sensitivity is 90. So since my speakers are 6 ohms does my set-up falls in the bracket of 130W +130W at 6 ohms.

Are my AVR-SPEAKERS matched.
 
@mpw, @shanmune @ coreElement,

So in other words is it always rewarding to go for a higher impedance speakers of say 8 ohms and 6 ohms, so that the AVR would be less burdened to release its power.

Nope, that's not what we're saying.

Because there are other variables other than just impedance to selecting a speaker. Not to mention written/specified impedance is usually always inaccurate since fixed impedance speakers do not exist other than probably electrostatic speakers.

If I have a 4ohm 91db 130w speaker and my amp is 80w at 8ohm I would happily pair it.

If I have a 4ohm 86db 130w speaker and my amp is rated 80w at 8ohm then I would think twice. Because the sensitivity is showing that the speaker draws 2x more db than the 91db speaker, add 4ohm to that and you have two variables saying "no".

An amp being able to drive a speaker vs the sound quality a combination puts out are two entirely different things. A lower power amp from x brand may sound better than a higher powered amp from y brand. And the reason would not be just because of impedance.
 
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it can dip to as low as 3 ohms while playing certain tracks.
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CorElement,

If I have a 4ohm 86db 130w speaker and my amp is rated 80w at 8ohm then I would think twice. Because the sensitivity is showing that the speaker draws 2x more db than the 91db speaker, add 4ohm to that and you have two variables saying "no

In your first situation you had given the example with sensitivity of 86 db. In the above ex. the sensitivity is for 91 db (i.e. a difference of 5 db) but you say the speaker draws 2 times more db than the 91db speaker. A bit confusing for me, will you please enlighten me in what I am missing. Regards.
 
CorElement,

If I have a 4ohm 86db 130w speaker and my amp is rated 80w at 8ohm then I would think twice. Because the sensitivity is showing that the speaker draws 2x more db than the 91db speaker, add 4ohm to that and you have two variables saying "no

In your first situation you had given the example with sensitivity of 86 db. In the above ex. the sensitivity is for 91 db (i.e. a difference of 5 db) but you say the speaker draws 2 times more db than the 91db speaker. A bit confusing for me, will you please enlighten me in what I am missing. Regards.

Suppose you have a speaker that is 91 db sensitivity at 100watts and a speaker rated 85db, there is 6 db difference in sensitivity. Every 3db reduction in sensitivity, the power requirement multiplies.

So suppose I have a 90db sensivivity 4ohm 120watt speaker and a 3 watt 2a3 amplifier where 1st watt is 60db spl, 2nd watt is 30 watt and 3rd watt is 15. The first two watts of 60+30 meets the requirement of the speaker of 90db and the remaining 1 watt which is 15db spl is the remaining headroom.

Within that 90db the sound signature has been established and you have 1 watt headroom which can drive the speaker but it wont play very loud.

I could have easily gone for say a 6watt amplifier but I love the sound of the 3watt over the 6watt. So I stuck with the 3watt and 15db headroom instead of a higher powered amp with a sound signature I don't like.

Notice how I did not give ohm's much attention. Reason being most of the times the 1st watt of 60db itself is often enough to comfortable listen and the speaker will not draw anything close to it's lowest impedance. If one wants to play things very loud, then it's a different story.
 
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Some FAQ insight from here, shared.
Speakers
QUOTE
Are 4 Ohm Speakers better than 8 Ohm Speakers?

NO!!! The Ohm rating of a speaker has nothing to do with the quality of the speaker!
What is an "ohm" rating anyway?

All speakers have a characteristic known as impedance which is measured in units called ohms. The most common values for speakers are 8 ohms and 4 ohms. Many older speakers have ohm ratings of 16 and even 32 ohms (this is because in the old days amplifiers used vacuum tubes, and higher impedance speakers were more compatible with the output impedance of vacuum tube amplifiers). A speaker with a lower ohm rating represents a more demanding load for an amplifier to drive. As stated before, the impedance of a speaker has no relation to the quality of the speaker.
Why do speakers come in 8 ohm and 4 ohm versions?

Many manufacturers of speakers (especially raw drivers) offer a choice of impedance... 8 ohms or 4 ohms. Often, the remaining specifications are very similar (except that the lower impedance versions of the speaker usually have a smaller sensitivity value). The reason for offering two versions is for special applications. For example, in a speaker system with dual woofers, two 4 ohm woofers can be wired up to form an 8 ohm system.

Some musicians prefer the "sound" of a 4 ohm speaker as compared to an 8 ohm version. I believe that this "sound" is not so much a result of the speaker itself, but a result of the heavier loading that a 4 ohm speaker places on an amplifier.

In the car stereo market, virtually all speakers are 4 ohms. The reason is due to voltage limitations available in cars (namely the 12 volt battery). More power can be driven into a 4 ohm speaker as compared to an 8 ohm speaker (assuming the same driving signal!).
What should I know about using 4 ohm speakers?

4 ohm speakers place a significantly heavier demand on power amplifiers as compared to 8 ohm speakers. Because of their lower impedance, twice as much current will flow through a 4 ohm speaker (as compared to an 8 ohm speaker) for a given volume control setting (assuming the amp can keep up). This translates to amplifiers getting significantly hotter (and heat is among the top enemies of electronic devices!).

If you use 4 ohm speakers, your speaker wiring will have to be (or should be) larger. This is because the resistance of the speaker wires becomes more significant with respect to that of the speaker. The result is that more power is "wasted" (in the form of heat) in the wires leading to the speakers! Amplifier power is relatively costly, so it does not make sense to waste that power in the lines leading to the speakers.

If you run two sets of 4 ohm speakers from a single amplifier (and the amplifier puts them in parallel), you are asking for trouble. The reason is that the combined impedance will be down around 2 ohms (and could actually be lower still... see below). A 2 ohm load is a load that only the most robust amplifiers will tolerate. There are amplifiers which are rated to be able to handle 2 ohm loads with no problems; however in my opinion operating a system in this configuration should generally be avoided. Despite the fact that the amp may be designed to handle the load, operating in this fashion places more stress on circuits and can lead to less reliability. You CAN drive a very low impedance load with most amplifiers so long as you keep the volume low. However, for practical reasons this is not often done.

Incidentally, you CANNOT make a 4 ohm speaker into an 8 ohm speaker by wiring a 4 ohm resistor in series with it (I once saw someone trying to do just this at Radio Shack). This will make the amplifier happier, since as far as it is concerned it has an 8 ohm load (which is easier to drive). However, resistors dissipate energy, they DO NOT generate sound. Wiring a 4 ohm resistor in series with a 4 ohm speaker will halve the amount of power which reaches the speaker (it will also degrade the damping factor, which won't hurt anything but it can degrade the sound quality!). Since amplifier power is relatively expensive, it would be extremely foolish to "throw away" half of it by wiring a resistor into the speaker's electrical path! Again, if you have 4 ohm speakers, you cannot change them into 8 ohm speakers... get an amplifier that is capable of driving 4 ohm systems!
Is an 8 ohm speaker really 8 ohms?

Not really! Due to the highly complicated nature of a loudspeaker, its impedance is NOT a simple number such as 8 (or 4) ohms. When a speaker is said to be 8 or 4 ohms, this is understood to be its nominal impedance.

A speaker system is an extremely complicated electromechanical device, and its behavior is correspondingly difficult to quantify. The impedance of a speaker system in actuality is said to be reactive; that is, in addition to resistance it can take on inductive and capacitive characteristics. An inductor is a device which stores energy in a magnetic field, and a capacitor is a device which store energy in an electric field. These characteristics are not "designed into" a speaker system; they are characteristics that are "inherent" (based on the physical laws which govern the way things work in our world).

Why do speakers take on reactive properties?
As stated, speakers are very complicated devices, so this answer will be highly simplified. When a signal is first applied to a speaker, there is a time delay which occurs before the speaker cone starts to move. This is because the speaker cone has a non zero mass. Basically, it is like a person trying to start a heavy cart in motion the cart will fight and tend to not want to move at first. Then, once the speakers cone is moving, and the input signal suddenly says "go the other way", the cone will resist the change in motion (again because it has mass and is moving in a particular direction). Basically, it takes effort to start a mass moving, and once in motion, it takes effort to stop it and make it go the other way! An amplifier must deliver more current in order to start a speaker cone moving, and when the amplifier signal tells the speaker "now go in the other direction", the speaker responds by generating an electrical signal which "fights" the amplifier! Again, this explanation is highly simplified. The best way to handle a difficult speaker load is to use an amplifier which has the ability to deliver tremendous current (and has zero output impedance). This will better keep a wild speaker "in line".

So, why do I need to know or care about this?
It is important to realize that even though a speaker may have a rating of 8 ohms, the actual value can vary greatly. The impedance of a speaker varies as a function of input signal frequency. As stated above, speaker impedance is in general reactive. This means that the impedance consists of a resistive part and either an inductive or capacitive portion (inductive and capacitive impedances cannot exist at the same time). The actual impedance (for an 8 ohm system) might vary from around 5 or 6 ohms up to as high as 50 or 60 ohms! The high numbers (50 or 60) are not so much the issue; it's the low numbers that cause trouble for amplifiers. Most amplifiers can easily handle the load of a "typical" 8 ohm speaker; the trouble comes in when one tries to drive two systems (in parallel) from the same amplifier. If you have an amplifier that is not too good with low impedance loads AND you have two "difficult" 8 ohms systems connected to it, you are inviting trouble. In general, amplifiers do not like to drive reactive loads (which all speakers are of course). The best way to combat this is to use an amplifier that can dish out substantial current (i.e. one that claims it is good with 2 ohm loads). Lesser amplifier designs will be the first to "quit" whenever difficult speaker loads are connected to it.

Advanced topics... As stated, the impedance of a speaker varies with frequency. If one looks at a complex impedance plot (generated with a variable frequency sine wave input), it can be seen that the impedance makes several "loops" on the plot. There will be several frequencies where the impedance is "real" (purely resistive). The first occurrence (starting from the low frequency end of the plot) of a purely real impedance occurs at the resonance frequency of the system (technically DC is the first "real" impedance, but is of little interest because normally DC is not applied to speakers). For most systems, this value will be somewhere between 40 and 80 Hz. The impedance at resonance is high, perhaps the highest value for the system (it might be anywhere from 20 - 70 ohms). A speaker system is very efficient (relatively speaking) at resonance. For bass-reflex speaker systems (which most DJ speakers are), the vibration of the woofer cone at resonance will be very small (however the amount of air coming out of the vent will be tremendous). The speaker system presents an "easy" load to the amplifier at resonance because (a) the impedance is purely resistive and (b) the impedance is relatively high.
UNQUOTE


Hope this helps.:)
 
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