GeorgePaul wrote:I keep hearing from Notion Support (Since version… 1. something...) I could get better sound quality out of an external audio interface rather than using the laptop's built-in card.
This is excellent advice, but understanding it might not be so easy . . . 
In the Apple universe, which for reference in some respects will be identical to the Windows universe, what one might call "primary audio' or "onboard audio" is handled by Intel High Definition Audio (a.k.a., "Intel HD Audio"), which is fine, but as with all all hardware, firmware, and software there are levels with respect to performance, quality, and so forth . . .
Intel High Definition AudioOn the Mac, audio is handled by Mac OS X Core Audio in conjunction with the various onboard hardware and firmware, and it is possible that Apple requires Intel to enhance some aspects of audio, although Apple certainly has custom requirements for other aspects of the Intel processors it uses . . .
With the Mac Pro, audio functionality can be enhanced in two ways, as is the case for a Windows desktop or server class machine with PCI Express or similar slots and various types of external ports (FireWire, Optical, USB), but for "all-in-one" Macs enhancing is done via external digital audio interface devices like the MOTU 828mk3 Hybrid, which works with Windows machines, as well . . .
Internally, digital music production applications work with digital audio, but at some point the digital audio must be converted to analog for purposes of reproducing the audio in the analog universe of signal processors, amplifiers, and loudspeakers, and this is where the difference in onboard audio and external audio become important . . .
If you rollback the clock to the early-1950s and consider an electric guitar rig where there is a Gibson Les Paul or a Fender Telecaster played through a Fender vacuum-tube combo amp (amplifier and loudspeakers), then this is purely analog, because there were no solid-state devices at the time other than perhaps in research laboratories, where as I recall the "transistor radio" did not become ubiquitous in the US until the late-1950s, at which time it was the equivalent of an iPod, even though transistor radios only played AM radio stations and were monaural . . .
Over the next few decades, solid-state devices became more prevalent, but there continue to be significant differences in solid-state power amplifiers and vacuum-tube power amplifiers, although it is
not uncommon for a vacuum-tube power amplifier to have solid-state rectifiers, but so what . . .
So what! The computer (Mac and Windows) works with digital audio, where the sound is represented by binary bits, but when it is time to reproduce the sounds in the physical world, the digital audio information needs to be converted from digital to analog, which is the reverse of what happens when the analog output signal an analog device like a microphone or electric instrument is digitized, where the analog output signal is converted to a digital signal . . .
By convention, analog-to-digital is abbreviated as "AD", and digital-to-analog is abbreviated by "DA", so for example if you want to get the analog output signal from a passive electric guitar into a computer, then you need an AD converter, and similarly if you want to use the digital audio from a computer to feed analog devices, then you need a DA converter, which from a practical perspective is one of the roles of what I call "external digital audio devices" like the MOTU 828mk3 Hybrid, since these types of devices provide AD/DA converters, as do PCI Express sound cards and so forth . . .
There are different types of AD/DA converters, where some are lower resolution and others are higher resolution on the digital side, and on the analog side there also are different implementations and technologies with respect to high-fidelity and other considerations, where one very important aspect involves balanced and unbalanced analog signals, where balanced analog signals map to the lowest noise, and the two most common strategies are TRS (Tip, Ring, Sleeve) and XLR, but impedance also is a key factor, and low-impedance devices like some high-quality studio microphones require preamplifiers and in some instances "phantom power" for the microphones . . .
Electric guitars with passive pickups and circuits nearly always are are high impedance devices, and in some scenarios it is possible for the electric guitar, guitar cord, and amplifier to function as an AM radio player, and in some instances a vacuum tube will behave as if it were a microphone, which is a clue that the vacuum tube needs to be replaced, among other things . . .
[
NOTE: In the early-1970s, Gibson made a low-impedance Les Paul guitar, which was intriguing . . . ]
And then there is the matter of everything in the analog universe being interdependent, where instead of everything being a set of one-way "pipes", the "pipes" typically are at least somewhat two-way, which affects the way everything works . . .
If you consider only the size and weight of a MacBook Pro and a MOTU 828mk3 Hybrid, it should be obvious that they are similar, which then raises the question, "Why?" . . .
Part of the reason is that the MOTU 828mk3 Hybrid has a virtual festival of 1/4" TRS ports, as well as two XLR/TRS ports, front panel Main Output stereo and headphone jacks, and on the back panel some Optical, Digital, and MIDI ports, as well as an internal power supply, LED displays, knobs, and so forth and so on, but even then there is other stuff, and the "other stuff" is focused on AD/DA conversions . . .
The problems with using the built-in output of a MacBook Pro, iMac, Mac mini, or Mac Pro are (a) that it is analog and (b) that it is unbalanced, although it is shielded . . .
The difference in "balanced" and "unbalanced" is that for example a 1/4" TRS to 1/4" TRS cable has two conductors and a ground shield, so that when the signal is balanced monaural, the two internal conductors carry signal and the ground via Tip and Ring, but the two internal conductors additionally are shielded by the outer metal ground shield (a.k.a., Sleeve), but when the same connectors and cable are used for stereo, then the inside two conductors carry the left and right channel signals, respectively, but they share the common outer ground shield, which makes it "unbalanced", where the important consideration is to have the signal traveling in both directions but inside a common outer grounding shield, since by having the signal going in two directions, this causes external noise, interference, and so forth to cancel, which makes everything very quiet . . .
With the MOTU 828mk3 Hybrid, the "stereo" output actually is a
pair of balanced 1/4" TRS ports, where one port is the left channel and the other port is the right channel . . .
There also are difference in the quality of the DA converter hardware, firmware, and software, where in the external digital audio interface strategy, the idea is to send the digital information from the computer to the external digital audio interface, where the DA conversion for output is made in the external digital audio interface using what in nearly every instance are higher quality components . . .
Whether it is possible actually to discern the difference in quality is another matter, and it is highly dependent on a variety of factors, where for example if the amplifier is a solid-state device and is a class D amplifier, then one should not expect the same listening experience as when the amplifier is a solid-state device but instead is a class AB amplifier, and there also is the matter of the loudspeakers and their characteristics, including frequency range, as well as the way the entire audio reproduction system is equalized and calibrated . . .
With the same set of loudspeakers, there will be difference if the amplifier is solid-state class AB, solid-state class D, or vacuum-tube based, and there are other solid-state classes . . .
Explained yet another way, if the amplifiers and loudspeakers are incapable of reproducing the analog signal with high fidelity, then there might be no easily discerned differences, but this does
not imply that there are no differences. Instead, it only implies that the amplification system is
not so good, which effectively blurs the actual differences . . .
But, as explained with examples in the Ethan Winer's audio workshop YouTube video, some of the differences are
not so easily perceived, where for example in the real world, the differences among 16-bits, 18-bits, 20-bits, 22-bits, and 24-bits are not so obvious when other stuff is happening, which is one of the reasons that standard CD quality is 44.1-kHz at 16-bits . . .
By the time the volume in the listening room is in the range of 85 dB SPL, nobody easily can determine much of anything in a very detailed way, and for nightclubs and similar venues this is not an unusual volume level and in fact probably is bit low . . .
However, 85 dB SPL is the
preferred sound pressure level for final mixing and mastering, at least here in the sound isolation studio, for a variety of reasons, most of which are explained in my ongoing topic in the IK Multimedia FORUM, which is focused on affordable
full-range calibrated studio monitor systems, which is fabulous . . .
The Fabulous Affordable Studio Monitor System Project (IK Multimedia FORUM)Fabulous! 
Posted: Mon Sep 10, 2012 9:40 pm
