A hi-fi system consists of a number of components that make music sound as good as possible. HiFi strives for clear, noiseless sound, not only with high volume and amplified bass. Music on a hi-fi system sounds radically better than music on the headphones that came with your phone due to many different factors such as less signal interference (and therefore less noise), higher frequency reproduction and clarity of the headphones and much better listening experience with over-ear -Kopfhörern.
People who love high-end audio are referred to as "audiophiles," and the audiophile scene is complicated and can seem hard. It describes what each part does in a hi-fi setup and how it adds to the overall sound.
Digital Audio Converter (DAC)
The DAC is essentially a very high-end headphone jack. It's the starting point for all the audio in your system. Due to electrical noise in your computer, the audio signal of the built-in headphone jack sounds very loud. You may not notice this sound on most headphones (as most headphones are loud anyway), but with hi-fi headphones, this becomes clear.
The solution is to isolate these electrical interferences with an external DAC. These components consist of components of significantly higher quality than the integrated DAC in your computer. They are often able to power higher impedance headphones and provide phantom power to microphones they need.
Most Speakers and Some Headphones Need an Amplifier Before you play the audio file, you may want to increase the sound quality, as it may be quiet when you come directly from the DAC. If you have a lower impedance headset, a USB DAC should provide power without any problem. However, if you need 250 ohms or more, you probably need an amplifier so the noise of the DAC will not ruin things.
The basic amplifier is necessary because most DACs are not designed to amplify audio beyond a certain point. Setting the DAC to 10 sounds incredibly loud (the bad sound). However, you can set the value to 5 and then set the amp to turn it up 200%, and the sound would still be clear.
Headphones and Speakers
All the above parts will digitally sound from your device via a cable. At the other end of this cable you have the choice between headphones or speakers.
Good speakers are complicated to set up and usually require a large stereo receiver to connect everything to. A good sound depends on the correct placement of the speakers and the room acoustics. This can be alleviated somewhat by suitable positioning and noise suppression fields.
Headphones are simpler and usually require only a single cable. These headphones have an impedance measured in ohms. This is the electrical resistance of the headphones. Higher impedance headphones require more power to drive properly. Most headphones are very low, usually below 32 ohms, while some headphones can reach up to 600 ohms. In general, higher impedances have better sound, but only if the rest of your setup matches in quality. If your DAC and amplifier can not handle the audio so much, you may not see any benefits – it might sound even worse than before.
When looking for headphones you should especially check the frequency response and overall clarity. Some headphones, like beats, will turn up the bass on the headphone to create the illusion of a better sound. For an untrained ear, this sounds very good, but a hi-fi setup should ideally have a relatively flat frequency response without altering the incoming audio. Overall clarity is hard to measure, but it does affect the sound quite a bit. This depends on the build quality and the price of the headphones.
Depending on usage, you may not need a microphone, but people who want to record audio simply add them to their setup. Most high-end microphones use XLR connectors, which are supported by most DACs. Some microphones, especially condenser microphones, require 48 volt phantom power, which means they need an external power source to work. However, the power is supplied by the XLR cable itself. So you do not have to connect anything extra, just turn off a switch on your DAC. Make sure, however, that you are not supplying phantom power to a microphone that does not support the microphone. Otherwise, the microphone could be damaged.
You obviously need cables to put everything together, but not all cables cut it. Since most of these components draw power from the wall, you'll need shielded cables. Normal aux cables that you can use to play music in your car are not shielded and pick up tons of static signals from nearby electrical signals. Shielded cables are an advantage, but they are necessary, because if a component in this loop is of low quality, it will ruin the audio quality. You do not need fancy, high quality, gold plated connectors or anything like that, but shielding is a must.
How does it fit together? For example, if you play a file in iTunes, your computer sends it to the DAC via USB. The DAC decodes it and then sends the actual analog audio to the amplifier (usually via a 1/4-inch cable, but sometimes over a standard headphone cable). After booting, the signal is routed to your headphones or speakers, where you can finally hear it.
The end result is amazingly clear tone.
What do I buy?
You do not need to buy crazy expensive components to have a great experience. Conversely, you can buy overpriced components and get noisy, distorted audio. It's about quality and it depends on each part itself.
The exact components of your setup vary depending on your needs, budget, and personal preference. The market is very diverse and therefore we can not simply put together a comprehensive guide to buying every single part you need. We encourage you to do your own research and read reviews by qualified audio professionals before choosing to buy.
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