Emmett,
I know better interfaces have better converters. How much difference does it actually make? Is it worth it?
Ethan
Hey Ethan,
In case you wanted a short answer, it’s a very subtle difference — one of the most subtle improvements you can make, in fact. That’s only really true with voiceover. If we were discussing music, my answer would differ.
For those playing along at home, the term “converters,” refers to analog-to-digital converters, and digital-to-analog converters. These are actually two different components that could behave very differently, but they tend to be very closely matched, in terms of quality. Thus, when discussing conversion, we’re typically referring to all aspects of the conversion process, in both directions.
I’ll simplify it even a little more. Or, rather, make it more complex, but in simpler terms. Analog-to-digital conversation is what takes the constant electrical signal from, say, a microphone, and converts it into a digital binary code. Digital-to-analog reverses the process, and converts digital binary code into a constant electrical signal, which will play back through headphones or speakers. Our ears hear only analog, but our DAWs only understand binary code. So a converter is the translator between the two worlds.
In a theoretical situation, these process would be 100% perfect, without the smallest deviation from each other. And actually, even inexpensive converters get very, very close to perfect. All converters designed for recording are currently very, very good. As technology has advanced, it’s just gotten better and cheaper. I’m not aware of anything on the market, designed for recording, that doesn’t sound good. Like so many other things, we’re talking about minuscule differences. But if you add enough tiny improvements together, you can achieve more serious improvement.
As I mentioned, they all do the job well. Several things contribute to differences. No matter how good the design is, digital is numerical, and therefore, finite. Eventually, we run out of decimal places. Eventually, between two numbers, we round. Analog is theoretically infinite. There is no division of numbers. To clarify, that doesn’t refer to analog recording, simply analog sound and electricity. Analog recording is limited by other factors. Being finite, errors will occur when capturing a sound, digitally. These errors present as noise. Better converters are able to get closer to the ideal, and exhibit less noise. Better precision, less noise.
Noise can also be caused by the analog circuitry that is coupled to the converter. The design choices of the analog part can also impact the overall sound quality in other ways. Once again, better converters do it better. Better components, better sound.
In every converter, there’s a word clock generator. This clock is what ensures the accuracy of the timing of each sample. That accuracy can vary by very, very small amounts — think accuracy down to 1/1,000,000 of a second. But the very best word clocks can be as much as ten times as accurate. That tiny bit of accuracy can make a difference. Because most professional converters are so good, the word clock is often what gives high-end converters different sound qualities. Two converters can sound equally as good, and can measure equally as good, but still sound slightly different. Just like with other high-end gear, it becomes subjective.
If you really want to get technical, you can read more in this study from MIT: https://www.mit.edu/~klund/A2Dtesting.pdf
When it comes to VO, a single voice isn’t a very complex signal, so it can be nearly impossible to hear differences with conversion. Music is considerably more complex, so differences are more obvious, and often present within the perception of the stereo field. With voice, we’re working with mono, and there is no other content sharing the space, which means the differences are more rudimentary.
Most audible differences for voice, can be attributed to the analog circuitry coupled to the converter, more than the converter itself. Everything about the design contributes something small to the sound, for better or worse. Even the quality of the power supply, and its proximity to the converter, can make a difference. Above a certain point, listening to the differences in converters requires both a complex signal, and an incredibly good listening environment, with very high-quality playback equipment.
Is it worth it? Well, I wouldn’t recommend a $7,000 rubidium clock, driving a $4,000 set of converters for any voice actor. So in that sense, no, it isn’t worth it. But when you take into account the other advantages of a premium interface, high-quality converters are part of what makes those units fall into the premium category, so in that sense, yes, at a certain professional level, I think a professional interface, with professional converters, is a worthwhile investment.
When it comes to more budget-friendly interfaces, conversion is, again, part of the package. Since almost all converters are very good, it’s not necessarily a high priority, but I do factor it in, when comparing interfaces. More than anything, it’s one extra thing to consider, but probably not something on which to base a decision.
Emmett
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