When it comes to speakers and audio systems in general, one term that often confuses consumers is “ohms”. Understanding the concept of ohms is crucial for ensuring compatibility and optimal performance of your audio equipment. So, in this article, we will briefly delve into the world of ohms and what it means for your audio setup.
First, it is important to get a general understanding of what we are talking about. Ohms measure the electrical resistance of a device, such as a speaker. In the context of speakers, ohms indicate how much electrical resistance the speaker presents to the amplifier. The impedance of a speaker is usually expressed in ohms and plays a significant role in determining how much electrical current the speaker will draw from the amplifier.
Some of the most common impedance ratings you’ll find with speakers is 8-ohm and 4-ohm. With 8-ohm speakers being the most common type found in home audio systems. The 8-ohm rating means that the speaker has a higher resistance, requiring less current to flow from the amplifier to produce sound. These speakers are generally more compatible with a wide range of amplifiers and receivers. They are ideal for home setups where the speakers are placed relatively far from the amplifier. So you will typically find this with most speakers you buy from common retail outlets (Sony, Bose, Klipsch, Polk Audio, etc).
8-ohm speakers are less likely to overload the amplifier, ensuring a longer lifespan for both the speaker and the amplifier. Additionally, 8-ohm speakers often offer a smoother frequency response and better power handling capabilities, making them suitable for various listening environments.
On the other hand, 4-ohm speakers, have lower resistance and require more current to produce sound. Potentially delivering higher volumes and better performance in certain situations. These speakers are commonly used in car audio systems and some high-end home audio setups.
However, there are considerations to keep in mind when using 4-ohm speakers. They can put more strain on the amplifier if the it is not designed to handle low-impedance loads, leading to overheating and distortion. Therefore, it is crucial to check the compatibility of your amplifier and speakers before making a purchase. Some amplifiers are limited to one or the other, while others can switch manually (usually a small sliding switch on the back) or automatically between both impedance ratings.
In most cases, you want to start by finding (and listening/previewing) the speakers you like best. Then pairing them to an amplifier that is formidable enough to drive them. 8-ohm speakers are typically the go-to for consumers who aren’t looking to call themselves audiophiles and it is easy to find an amp capable of driving them since most amplifiers will. Although it is common for an amplifier to support both, it isn’t always the case.
Then you have the practice of wiring speakers to each other (chaining them onto a single output/channel). This is something else you should be careful with since this changes the resistance the speakers present to the amplifier. It also depends on how you wire these speakers together. The two common ways is in “series” or “parallel”. When wiring two in series, you would add their impedance ratings together (two 8-ohm speakers will result in a total of 16 ohms to the amplifier). When wiring two in parallel, you would decrease the rating by half (two 8-ohm speakers would result in a total of 4 ohms).
In most cases, you wouldn’t be daisy-chaining speakers together though. You would be wiring a single speaker to each channel (left and right, or multiple channels for surround). This is usually for creative design, custom built cabinets, and other unique situations. So if you find it confusing when it comes to wiring them together, it’s best not to venture down this path (or let someone else advise you on the process).
Understanding the difference between 8 ohms and 4 ohms is essential for creating a balanced and efficient audio system. Consider your listening environment, amplifier specifications, and power requirements before making a decision. By choosing the right speakers for your setup, you can enjoy optimal audio quality and prevent potential damage to your equipment, ensuring a satisfying listening experience for years to come.
Of course, wired headphones are a completely different beast. Mostly since you likely won’t be building your own headphones. So you only have the option of matching a single impedance rating (of a pair of headphones) to an amp/source (headphone amplifier, mobile device, computer, etc). The average mobile device or computer is capable of handling a reasonable range since headphones come in all sorts of impedances.
Specifically, headphones can usually range between 8 and 600 ohms with the average being 32 ohms. Almost all devices will support up to 32 ohms since you don’t need to really amplify anything. Once you go above 32 ohms, amplification may become needed and the amp source may have to support this (mostly as you go above 80 ohms). This is why some computers and mobile devices brag about having a “built-in DAC” to help deliver exceptional headphone performance.
So you can go with headphones that feature an impedance between 8-32 ohms with virtually any device. Up to 80 ohms will also be supported by most devices, although those that provide amplification could get a little more volume out of those closer to 80 ohms. Once you breach 80 ohms, you definitely want amplification, else you will quickly start losing volume.
So if you pair a 600-ohm pair of headphones with a basic mobile device, like these Beyerdynamic 880 SE Premium 600-Ohm Headphones, you likely aren’t going to get much volume at all. Before we had mentioned that higher impedances lead to less current from the amplifier. However, although you may require less current, it does requires additional voltage to obtain the current needed. Since many of these devices are dependant upon battery power and are not plugged into the wall, you can imagine why this could become an issue. So nicer devices will take advantage of DACs for increased amplification and handling.
This is where solid-state and tube amplifiers come into play. They typically plug into the wall and offer various build qualities. Some can still be limited to lower impedance headphones while others can drive 600-ohm headphones easily. Of course, the latter will usually cost you a bit more (sometimes, a lot more).
So it is good to make sure when shopping for a pair of wired headphones that the device you plan to drive them with is capable of properly handling their impedance. Check the compatible impedance range of your device against the rated impedance of the headphones. With the exception of using wireless headphones in Bluetooth mode as this will take advantage of amplification built directly into the headphones themselves and not from your connected device.
Co-Authors: Kryton Bailey