What Does A DAC Do?

If you’ve begun your journey down the rabbit hole of audiophile equipment, you may have come across the term DAC – or ‘digital-to-analog converter’. What is this piece of equipment? Is it a necessary part of the audio chain?

This article aims to demystify DACs and leave you in an informed decision to decide how to explore your next audio equipment.

MSB Technology Discrete DAC

What Is A DAC (Digital-To-Analog Converter)?

A DAC simply transforms a digital sound wave to an analog signal, which may then be played through speakers or headphones. The DAC processor is located in the primary part you’re listening to, whether it’s a mobile music player or a smartphone.

Similar to headphone amplifiers, standalone DACs were developed in response to consumer-level audio quality problems. High-end headphones and speakers may show the weak spots in the sound chain as DACs, source components, and output stages. This became more clear when people began utilizing their PCs as audio sources.

Cayin IDAC-6 (From Cayin)

The DAC’s screening were often weak, poorly insulated, creating noise, or the power supply could be poorly controlled, affecting the clarity of the produced output. Lower sample rates and poorly encoded MP3s were a slew of issues that people in the previous decades had to cope with when it came to sound.

But, in the intervening years, digital music has upgraded. Better technology has rendered the flaws of even the most basic processors virtually inaudible, while digital music has increased in clarity beyond the point of declining returns. Whereas it used to be that your digital Walkman or laptop’s inbuilt DAC chip couldn’t handle high-bitrate listening, there are now lots of portable devices that can.

How Does A DAC Work?

When replayed, any audio, whether saved in an MP3 or on vinyl, produces a compressed wave. When a computer records an analog signal, it typically displays it as a waveform, which is a representation of the wave with the Y axis showing amplitude and the X axis representing time. Each wave has a crest and trough, which is referred to as a cycle, and the number of cycles in a second is referred to as frequency, which is shown as Hz. The higher the note, the greater the frequency.

The DAC’s purpose is to convert the digital signals that make up a saved audio into a smooth analog output. To do so, it must convert bits of data from digital records into analog electrical signals at thousands of preset times per second, also known as samples. The mechanism then generates a wave that connects all of those spots. Because DACs aren’t ideal, this can occasionally cause issues. These issues include high frequency mirroring, jitter, a small dynamic range, and a low bitrate.

Before delving into the specifics of how everything works, you should be familiar with three terms: bit depth ,bitrate, and sampling rate. The term “bitrate” basically means to the amount of data expressed per second. The sample rate is the number of data samples captured each second, and the bit depth is the amount of data recorded every sample.

What Is Aliasing?

Aliasing happens when there are less than two samples each cycle and a group of sampled pieces of data can be misconstrued. Aliasing occurs only when a data is sampled during analog to digital conversions in a digital downsampling or an ADC and applies to inaccuracies in the signal spectrum caused by sampling just beneath Nyquist rate.

5: An example of aliasing in the time domain. The two signals have the... |  Download Scientific Diagram

Aliasing does not occur at a DAC’s output. If there isn’t an appropriate lowpass restoration filter at the DAC output, pictures of the original signal spectrum will recur at multiples of the DAC frequency response. If not appropriately filtered away, the image spectrums created by high frequency mirroring might cause multiple conflicting in the audible signal.

Because the highest limit of human hearing is thought to be 20kHz, or 20,000 cycles per second, when you double the rate yields at 40,000 samples per second. Applying 10% for the rolloff of the lowpass reconstruction filter results in 44kHz.

What Is Jitter?

Jitter is largely a hypothetical issue at this moment, and it is exceedingly improbable to appear in any technology manufactured in the recent decade. However, knowing what it is and when it can be an issue is still essential, so let’s get started.

So, recall how we mentioned that sample rate can cause issues? Jitter is one that garners a huge amount of interest but little comprehension. Jitter arises when the clock, which instructs the DAC when to transform each sample, is not as exact as it should be. When sample points are not processed in a timely manner, this might result in a shift in tone for brief periods of time. The greater the pitch mistake, the higher the note being duplicated.

Nevertheless, it should be noted that this is another of those issues that is no longer as widespread because DAC devices nowadays are far superior than those of the past. High-frequency sounds, on the other hand, are less likely to be noticed because they are more prone to this type of inaccuracy.

What Is Dynamic Range and Bit Depth?

If you’ve listened to very old MP3 format from your old devices, you’re surely aware that the volume level in a particular music track is quite constant, or that conflicting sound instruments are truly hard to select out when they’re all playing simultaneously. This is how a low dynamic range sounds. In this case, dynamic range basically applies to the gap between the lowest and highest attainable output volumes.

The bit depth of a sound version determines the potential limitations of its dynamic range. Essentially, every sample has details, and the more details a sample has, the greater possible output values it has. In other words, the higher the bit depth, the higher the spectrum of possible note loudness.

What Is Dynamic Range, and Why Does it Matter? - Yamaha Music
From Yamaha

A low bit depth, either during the recording process or in the file itself, will inevitably result in a poor dynamic range, causing numerous sounds to be inappropriately exaggerated or muted entirely. Because there are only so many distinct loudness levels within a digital file, the lesser the bit depth, the poorer the file will sound. So, the more bit depth, the better, right?

The most typical bit depth is 16, which means that each sample can include up to 16 bits of details. That translates to a dynamic range of 96.33 dB in audio. In theory, no sound less than 96 dB below the maximum point should be lost in the noise.

So, why do so many people insist on 24-bit audio when 16-bit is perfectly adequate? Since that is the bit depth at which human hearing should never have any issues. If you like listening to songs that are incredibly quiet — and you have to turn up the level to hear everything — you need a lot wider dynamic range than you would with an excessively produced, too-loud pop song to be effectively heard.

While you’d never crank your amplifier to create 144 dB (SPL) peaks, 24-bit encoding would enable you to go close without worrying about the noise floor on the recording.

Furthermore, while recording music, it is usually preferable to capture at a high sample frequency and subsequently downsample, rather than the other way around. As a result, you escape having a high-bitrate file with low dynamic range or, worse, extra noise.

What Is A Good Bitrate?

While bit depth is crucial, most listeners associate terrible audio with either inadequate bitrate or severe input audio reduction. Have you ever listened to music on YouTube, then switched to an iTunes song or a high-quality streaming site and quickly noticed the distinction? You can tell there’s a variation in data reduction performance.

If you’ve read this far, you’re presumably familiar that the higher the bit depth, the more data the DAC has to process and produce simultaneously. This is why bitrate, or the speed at which your audio input is decoded, is significant.

So, how much is too much? We normally recommend 320kbps for most purposes, supposing you’re listening to 16-bit files. A few of you favor FLAC files, but what about for mobile listening? Simply use a 320kbps Opus file or MP3; audio reduction has come a long way in the previous 20 years, and newer compressing methods can accomplish a lot more with a lot less than they used to. A low bitrate isn’t a dead indication that your audio will be awful, but it’s also not a good indicator.

If you have extra space, you may not care as much about the size of our files—but smartphones do not all come with 128GB standard storage… yet. However, if you cannot detect the variation between a 320kbps MP3 and a 1400+kbps FLAC, why would you waste 45MB of capacity when 15MB will suffice?

Why Do You Need a DAC?

The major reason you’d purchase a new DAC currently is if your present system—whether it’s your smartphone, computer, or home system—has noticeable unpleasant distortion, noise, or artifacts, or is unable of running at the bitrate of your audio files. If you already own an external DAC and are experiencing any of the aforementioned concerns, you should read this post.

Alternatively, if you’ve persuaded yourself that your current DAC is the major bottleneck in your listening setup and that replacing it will result in a significant upgrade, that could be regarded a justification to invest as well. This would also be classified as “searching for something to spend money on,” which is not the optimal use of your funds in terms of upgrading prospects.

FiiO E10K DAC (From FiiO)

Because DACs are generally component products, you can nearly always tell which one you need just by checking at the box. FiiO makes a lot of fantastic items for a low price, and if you want an amplifier to go with the DAC so you don’t have to bother about that, their E10K is a great choice for around $100. You could also throw money at the issue by purchasing an ODAC or O2 amp + ODAC combo, but this may be overkill. But, really, don’t invest too much money in this. It’s simply not worth it.

Frequently Asked Questions

1) Is it possible to utilize a DAC without an amplifier?

A DAC cannot be used in the absence of an amplifier. A DAC’s main function is to transform digital signals into analog waveforms. The audio stream is too weak to be detected by the sound source after the conversion. As a result, an amplifier is required to enhance the signal to an acceptable level.

2) I have high impedance headphones. Can a USB DAC assist?

Yes, if the USB DAC contains a headphone amplifier with a sufficient output power, it will assist in correctly driving your headphones and get the most out of them. However, the amplifier is the most significant factor in your case. A solitary amplifier might also suffice.

3) Is A DAC required if I use Bluetooth headphones?

No. Do not purchase a DAC for Bluetooth headphones, as they already include a DAC chip to transform the digital signal to an analog signal for transmission to the headphone’s drivers. A second DAC would be unnecessary.

Conclusion

The end goal is great sound, and a good DAC can help you get there. Any of these alternatives can enhance the sound generated by your current audio system. All you have to do is pick the correct DAC for you, connect it in, and relax.

Whether you’re updating your home theater system or simply looking to boost the sound on your laptop, a high-quality DAC may make all the difference.

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