What Audio Interface Makers Don’t Want You to Know
Imagine for a moment that you are in charged of a marketing team of a car maker company. And there’s one important crappy part that if everybody knows about, it will affect the sales badly. Then would you reveal that secret to the market?… Yes, what a stupid question that was. And this applies to all the audio interface makers too.
Luckily, there are not as many parts in an audio interface that we care to know about like cars.
- Heart & Soul of a Sound Card
The most important parts of an audio card or interface are a digital signal processor (DSP chip), followed by the converter – an analog-to-digital converter (ADC), a digital-to-analog converter (DAC) and an operational amplifier chip (op-amps) that defines the sound quality.
One of a few of the most important parts in an audio interface is the converter chip that only a handful of manufactures do reveal its grade. Unless, it’s a very very good converter like those 6 figures dedicated interfaces (Apogees, Pro Tools HDs, etc.), you will never know what converter they use unless you look hard enough. This fact makes the big gap between the poor and the rich interfaces. And the rest of the specifications that we often see on the side of the boxes, sadly to say, they are not as essential to your recording sound as the converter chip.
And faster a sound card’s DSP chip can process results in more accuracy timing (latency), you don’t want to hear any unintentional delay shooting back at you from your speaker after strumming a chord. But I won’t get into that technique just yet. But for the record, you should know by now that this is handled by a sound card processor chip (DSP Chip). This handle bits and sampling rate khz that are just something many of us have been fooled for so long. You must wonder why a $20 dollars sound card can offer a 24bit rate with 48 Khz sampling rate as well as those $10k cards?
This might sound a little funny but what makes an audio interface sings great and costs more is the loudness capability. Loudness? Am I stoned? Not today.
As loud as it gets, please.
Even though I am not that into loud music. But I have to appreciate the fact that the quality audio interface components or parts that directly handling audio wave, it all comes down to the loudness. The louder the better. And the quality of the converter that converts your sound live instrument sound into digital waveform that you can see on computer screen and wise versa is relying on that. Why? The higher volume (wider dynamic range) an audio interface can handle the lower the noise ratio. And that means, clearer and cleaner sound. This is because when you turn up your volume you’re not just making what you want to hear sound louder but also the unwanted noise too (it’s always there but you won’t hear any noise until you turn volume up so loud, as you may have heard).
Therefore, if an interface can handle more volume then it would mean that the noise will be lower. Consequently the sound you want to hear has less noise which makes the sound cleaner even at the higher volume. And that’s when another term like ‘headroom’ comes into play. The more headroom your DSP chip and converter chip can provide means higher the volume it can handle. That’s why 6 figures cards won’t let you have as many tracks as you want like cheap ones do since it know its capability and won’t let you overuse it that will result in low quality sound.
And these facts surely won’t be advertised as much as how many bits an audio interface has. Now the secret is out. However, remember that, the most important thing is your ears, nothing can be a better judge of sound quality than that.
- DSP Chip
An integrated circuit, usually in the form of a microprocessor, designed specifically for high-speed signal processing (i.e., data manipulation) tasks, typically in real time, and built into another device. In a typical telecommunications application, an analog-to-digital converter (ADC) samples an analog signal and converts it into digital format.
A DSP then encodes the signal into pulse code modulation (PCM) format, employing an appropriate algorithm such as A-law or mu-law to produce a standard output like a DS-0 channel. A DSP might then filter noise and remove interference from the signal, and transcode, compress, and perhaps encrypt the signal prior to placing it on a carrier of an electrically based digital circuit for transmission. A matching DSP reverses the process on the receiving side of the communication, sending the signal to a digital-to-analog converter (ADC) for decoding back into real world analog form, perhaps with improved clarity, a shifted frequency, or demodulated. DSPs are used in audio, communications, image manipulation, and video applications. DSPs are built into cellular telephones, fax machines, modems, and many other devices. Source
- Converter Chip (ADC)
A device in the form of a chipset that receives analog signals, measures the input at a regular sampling interval (or on command), and reports a digital output of the results. In a typical application, an ADC samples the analog signal at a fixed interval with enough resolution to accurately describe the analog waveform. In a typical voice application, for example, an ADC samples the audio stream 8,000 times per second at a precise interval of 125 microseconds ( 1 / 8,000 of a second) and reports a 14- or 16-bit value per sample. A digital signal processor (DSP) or other hardware then encodes the signal into pulse code modulation (PCM) format, employing an appropriate algorithm such as A-law or mu-law to produce a standard output like a DS-0 channel. At the receiving end of the connection, a matching DSP or other hardware and a digital-to-analog converter (DAC) reverses the process.
Audio Interface Simple Buying Guide
Numerous factors affect a sound card’s abilities to provide clear, high-quality sound. When shopping for a sound card, pay attention to:
ADC and DAC data capacity, measured in bits
Signal-to-noise ratio (SNR) and total harmonic distortion (THD)
Frequency response, or how loudly the card can play sounds at different frequencies
Output channels, such as 5.1 or 7.1 surround sound
Supported application programming interfaces (APIs)
Certifications, including Dolby Master and THX
Anyone investing in a top-of-the-line sound card should also have high-quality speakers. Even the best sound card cannot compensate for poor speaker quality.
Digital-to-Analog Converter (DAC)
Close-up of a sound card