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How does cable length affect sound quality?
How does shielding and insulation help?
Separate fact from fiction in this ultimate guide!
When we set up an audio or video system, we usually don’t have control over the size or layout of a room. We have to snake our cables around furniture, connect speakers on opposite walls, or place any front gear of amplifiers wherever they can fit. If we’re setting up the sound for an event, we may even have to clear a huge space for performance areas or for audience passageways.
Unfortunately, this also means that all our audio equipment has to be connected with really long cables and interconnects. The messy jumble of wires is already bad enough, but audiophiles say that leads to signal loss, noise, series resistance, and a general deterioration in the quality of the sound.
On the other hand, there are plenty of people who say that any sound loss makes no difference–unless you have superhuman hearing. They actually think all the “fuss over cable length” is an overreaction.
So in this article, we go into the heart of the debate. Does cable length affect audio quality? Are shorter audio cables always better? What kind of devices or types of cables are more prone to sound deterioration? Let’s get started.
So, Does Cable Length Actually Matter?
Yes, cable length does matter when it comes to sound quality, and it is something you will need to consider. However, the extent to which this is true varies from situation to situation.
The good news is the cables you already have are probably fine even if they are long. But if you have tried – and failed – to use even longer cables without noise creeping in, there are a number of factors you might want to investigate here.
First, let’s look at how a speaker cable works. These cables must transmit signals from the speaker to the amplifier. The most important factor in the quality of the signal is the cable wire’s electrical resistance.
Electrical resistance is the opposition to the flow of current. The higher the resistance, the more energy is converted to heat. The lower the resistance, the more power (and in the case of a speaker cable) and sound stay intact.
Electrical resistance is affected by both the cable length and thickness. So yes, a longer cable can affect your sound quality—but the question of how much it affects it depends on other factors. This includes:
A thicker speaker wire will have less resistance, which helps preserve your sound quality even for long cable runs. For example, very heavy speaker cables of about 16-gauges can stretch for as far as 50 feet (15 meters) without affecting your listening experience. So its thickness is able to compensate for the distance.
Thickness is measured in SWG (standard wire gauge) and AWG (American wire gauge). The smaller the SWG or AWG number, the thicker it is. In some cases, a cable manufacturer will also measure thickness by giving the strand count.
If you are designing your home or office audio system, look at how long the cables will need to run. Then, you can select the appropriate gauge wire thickness for each distance limit.
Use this guide to help you:
3 to 12 feet
5 to 20 feet
8 to 32 feet
12 to 48 feet
20 to 80 feet
30 to 120 feet
50 to 200 feet
Note that there is a range given in feet rather than a strict length because the resistance is also affected by your speaker impedance. A 2 OHM speaker can have a maximum length of 3 feet for a 22 AWG, while an 8 OHM speaker can have a maximum length of 12 feet.
Quality of the Wires and Insulation
Most speaker cables are made of copper wire or copper-clad aluminum. That’s because this metal has low resistance and is generally more affordable than other metals. Some of the cheaper cables don’t use good quality copper or use bad insulation that either exposes it or reacts to it.
This turns copper into copper oxide, which has a higher resistance and will cause a lot of signal loss. That interference can be more apparent with a longer cable.
You can also find speaker wires made of silver or gold, which have their own resistance qualities.
While the cable length, thickness, and material changes resistance, that still leaves the question of how it will affect the actual sound quality.
As a general rule, the resistance will only have an audible effect if it is greater than 5% of the speaker impedance, which is measured in OHMS. The lower the impedance, the more likely that it can be impacted by resistance and the length.
However, audio and sound experts say that speaker impedance is not a single value. It can fluctuate according to the frequencies. A sudden increase in frequency can show a higher impedance. In terms of your listening experience, you’re more likely to notice any RF interference if you’re listening to something with very high or very low frequencies.
Other factors that can alter output impedance is whether the device is in a sealed enclosure, or if it is in open air.
The most common balanced cables are XLR cables, followed by TRS cables. Because balanced connections are designed to eliminate noise and interference, they can theoretically be of any length. In a live setting, it’s not uncommon to see XLR cables that are long enough to bungee jump with.
How Do Cable Lengths Affect Subwoofers?
The sound quality deterioration also depends on the kind of devices you’re using and the kind of audio signals you’re sending. In one forum, a sound engineer observed that subwoofers seem to be more affected by the cable transmission. That’s because it feeds a weaker audio signal at pre-amp levels (millivolts) to an amplifier inside a remote speaker cabinet. So it is more likely to suffer signal loss than stronger volt-level signals sent by speakers.
But like speaker cables, the quality of your subwoofer connectors can make a big difference in reducing noise. An RCA cable can pick up electromagnetic interference (EMI), particularly if it is positioned near other household electrical connections. That can cause a low humming sound when you try to listen to music or watch a movie on your home audio system.
In one forum, a sound technician suggested replacing the RCA cable with a shielded coaxial cable between the amplifier’s subwoofer output and a remote subwoofer. He explains that any pick up will be intercepted by the shield and routed to the ground of the subwoofer power amplifier.
You can also get a high-quality subwoofer cable that is thicker and more resistant to EMI. Look for braid or dual braid shielding, or sidestep the problem entirely and get wireless subwoofers.
If you’ve already got a subwoofer, you can hook it up to a wireless subwoofer kit that can then transmit the signals. These products usually have an operating range of 12 meters.
How Do Cable Lengths Affect Headphones?
People are willing to spend top dollar for headphones that retain the integrity of the sound. That’s true for audiophiles or music lovers who want to get the best possible listening experience, or music professionals and sound technicians who need accurate sound to create quality work.
But when people shop for headphones and other products, cable measurement is often the last thing they are thinking of (as long as it’s long enough, right?). Does cable length matter for headphones, or is this only an issue for speakers or other equipment?
The thing is, headphone cables are vulnerable to interference because of the weak voltages. As the sound passes through conductors, there’s an inevitable loss in the sound quality. So, the shorter the cable is, the better your output will be.
However, some people need to have longer headphone cables. If you’re a DJ or a musician, or in charge of the sound on a stage or event, then you want more mobility. Luckily, the material and construction of your headphone cables can help minimize interference and noise.
Headphone cables are frequently made from gold, copper, silver, or rhodium and budget headphones often use silver-plated copper. But if you can afford it, look for one made from high-quality copper. This low-resistance metal can help slow down any signal loss.
There are also premium headphone cables that have oxygen-free copper clad wire. This means that it won’t oxidize, even if you’ve used it for a long time. As we mentioned earlier, copper oxide has a high resistance and will result in more interference.
You can also invest in a low pass filter cable, which controls capacitance and inductance to minimize signal loss. Choosing a thicker cable can also help balance any issues caused by length—and has the added bonus of not getting tangled up. We all know the frustration of tangled headphone cords!
Does Cable Length Affect Microphones?
According to audio professionals, it depends on many factors. Theoretically, any audio loss would be too negligible to affect your sound quality. There are cases where people have used 35 feet XLR cables with no problem at all.
However, the problem arises when the noise is generated in the microphone cable itself (aka microphonic noise). This can occur when the cable is flexed or bent, which leads to static discharges. The cable then acts like an antenna, which picks up the RF and amplifies it.
Unfortunately, the longer your cable, the higher the chances that it’ll get twisted or tangled along the way. If you really do need a long cable, this can be solved by using a higher quality XLR cord. Unlike thin, low-quality cables, this can neutralize distortion or noise, and help keep your recording “clean.”
Other audio pros say that it depends on the type of impedance sources. One forum user, who says he works for a radio station, said that if the Hi-Z source is resistive, then the long cable produces an attenuated high-frequency response.
But if that Hi-Z source is capacitative, you may hear a reduction in output but with no difference in the frequency response. In both cases, you are more likely to notice changes in the AM bandwidth.
Lastly, cable length is less likely to affect microphones that have less than 1000 OHM. Some recommend sticking to a 150/600 OHM mic if you expect that you will have to use it with longer cables.
Are HDMI Cables Also Affected By Length?
HDMI cables send digital video and audio signals between devices. Even if you’re not an audiophile or music professional, you probably already have these in your home. They’re often found on the back of your TV, game console, or sound system—and look a bit like the USB port on your computer. No home theatre system can work without one.
Most manufacturers will sell 50 feet HDMI cables, which may lead users to think that it’s the “standard” or “optimum” length. However, like all other audio cables, the signal deteriorates as it passes through it. If you read the fine print or the manufacturer’s website (and let’s be honest, most of us don’t), you’ll find that they recommend using some kind of signal booster beyond 20 feet.
For most home users, the difference is too small to notice. If you’re watching a 720p or 1080p video on Netflix, you may even have 70 feet HDMI cable and feel perfectly happy with the audio quality.
But if you’re an audiophile, or in commercial situations where noise and interference can ruin a recording or broadcast, HDMI cable lengths can become quite a headache. There are cases where the cable box or TV blanks out right in the middle of a job!
Another common issue is when set-up requires multiple HDMI cables, which can “cross-talk” and eventually overcome the broadcast signal. In this situation, you may need special equipment—coax cables, a special transmitter box, and a receiver box—to help transmit RF outputs with minimal distortion.
Nothing like 4K resolution, so if you have a great 4K TV great 4K player you better get good 4K cables. The length of the ibirdie HDMI cable is from 3 feet to 328 feet, all cable compatible with 4K resolution of HDMI 2.1 TV.
How Do I Protect Audio Quality If I Have A Longer Cable Wire?
So we have good news, and we have bad news: audio quality is affected by the wire length, but some cables are better at protecting the sound and minimizing interference.
Common workarounds are getting thicker cables, or getting cables with high-quality copper wire. Depending on your device compatibility, you can also try getting XLR or balanced cables. These can stretch up to about 100 feet or more and yield absolutely no distortion.
You can also get signal boosters, or adjust your pre-amplifier’s output impedance. Audiophile forums are full of great suggestions from other sound experts who have struggled with similar issues with distance and length, and were able to find specific solutions based on their device and setup.
So in other words, you don’t have to feel stuck with bad sound quality just because you can’t shorten your cable. For every problem, there’s a solution.
As one audio expert said, “every audio setup is about making compromises.” You may have to adjust the position, switch to an XLR connection, move around the power supply, or endlessly tweak your settings. It may take time, but eventually you’ll solve the problem.
Just like having the “perfect” cable length won’t guarantee the perfect sound, having really long cables won’t necessarily mean you’ll have to live with RF pickup and distortion forever.
And – to put perspective into this dilemma – the amount of sound loss may or may not actually make any real difference to your listening experience. That depends on your needs, devices, and the kind of audio or video that you’re working with.
For home theater setups, cable distance is not likely to ruin your Netflix marathon. For professional studios, even the slightest distortion can make a difference.
But if you’re noticing your home theater sound is dull or noisy no matter what you do, there’s a good chance the cable length could be to blame. Check to see if you can replace your cables with shorter ones and opt for high quality, durable cables that will last a lifetime over cheaper cables with less shielding.
At the end of the day, once you consider your specific needs and do a bit of extra research you really can’t go wrong!