This is spl in db at 1 watt 1 meter. The other is to apply 2. Now I think you can see that a 4 ohm speaker will have a higher rating with the later method as it will be taking more power. Power is voltage squared divided by resistance. Now the db scale is log. So under the same conditions of test a speaker with a 3db increase in sensitivity has the same effect as doubling the amp power to the less sensitive one.
The other thing is max spl, which is not usually quoted, and varies with frequency usually. For instance power is often limited in the bass because of limitations of cone movement xmax. Speakers seemingly so simple are in fact complex. There are a lot of specs that are hidden by manufacturers. One of the most useful pieces of information is the waterfall plot.
Only the best manufacturers publish those. Specs are easily and often manipulated by manufacturers to their advantage. Even then you can not judge a speaker by the specs. You have to listen. A good spec. As long as your amp is capable, you can use a 4ohm speaker to get more out of your amp so to speak Rickster71 said:. An amp that is 4 Ohm capable will have no issue driving an 8 Ohm load, so the amp side is not so much a factor unless it is insufficient for the load.
So back to the speaker itself, a 4 Ohm of the same sensitivity will draw more current from an amp than an 8 Ohm one. I currently own 8 and 4 Ohm variants of the same family of speakers and they do not sound noticeably different.
HDOM said:. Last edited: Mar 15, I think it was meant in the context of having an amp that wasn't necessarily up to the task of lower impedance. A W amp isn't likely to have that issue relative to the original question, though if one were using something that is fine with an 8 Ohm speaker but might be pushing its limits with a 4 Ohm then clipping would be more likely.
A situation that is likely to occur when the amp is already in place and then speakers that exceed that capability are chosen after the fact. There is far more to this then 4 ohm verses 8 ohm and everyone keeps forgetting the affects of phase angle. A 4 ohm speaker with a low phase angle is by far an easier load to drive than a 8 ohm speaker with a high phase angle. Talking about speaker impedance without including phase angle is meaningless. You must log in or register to reply here.
Latest posts. Incongruous media coverage of Rittenhouse vs actual testimony Latest: lovinthehd A moment ago. The Steam Vent. This is one of those questions that get asked a lot. In this blog post, we will be explaining everything you need to know about these two types of speakers, including the differences between them, and why impedance matters. A lower impedance rating means less power will be lost in transmission, but this can also mean more amplifier power is needed for adequate volume levels.
The lower the impedance, the more power it takes for adequate volume levels and vice versa. A typical home speaker will have an impedance in the range of 4 to 8 ohms or multiples thereof. Home Theater. Joined Jan 5, Messages 7 Points 0 Location new york.
CorElement, If I have a 4ohm 86db w 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. A bit confusing for me, will you please enlighten me in what I am missing.
CorElement, Thanks a lot. Confusion cleared completely. Some FAQ insight from here, shared. 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 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? 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 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. 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 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.
0コメント