Which performs better 3.5mm or USB for audio output?

I am evaluating and researching a new pair of active speakers for my ~2 year old mac-mini. I mostly listen to classical, jazz and some ambient sounds. I am currently favouring the Audioengine A2+ which connect via USB. Their physical size is also ideal for my current space.

However, I have been reading about other top reviewed active speakers which can only connect via analog 3.5mm stereo jack. I am under the impression that USB is a digital connection which has less loss than its analog counterpart - therefore a superior audio output quality. Is that technically accurate?

The other challenge I have is that a few times a week, I need to connect my headphones to the 3.5mm jack on my mac mini which would mean I would have to disconnect/reconnect my speakers and the jack is in the back of the computer.

I am curious to learn more about 3.5mm analog vs USB digital which, I am hoping, will result in helping me make my final choice. I look forward to hearing from you. Thank you.

This might be helpful:

As far as whether to use an external DAC or not, it can be a really religious argument, with lots of subjective opinions. I tried a friend’s DAC (dragon fly?) on my 2015 MBP and couldn’t hear any difference (at the time I really wanted to justify buying a DAC too). I think I have a pretty good ear, and can hear the difference in Apple Music’s version of songs and HD Tracks’ FLAC versions. Amazon has a liberal return policy, so you could order a few things an audition them to see what you like.

Our brains seem to, though.
Thanks to the missing fundamental, we seem to hear frequencies lower than the ones actually in the sound we’re hearing. If a sound has 200, 300, 400Hz components, we will “hear” a 100Hz component too.

This is why AirPods, etc. seem to have good bass response, even though they can’t produce those low frequencies. Of course while you will hear those low frequencies, you won’t feel them in your belly, which takes a larger speaker and power.

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There is no real difference between transmitting the signal digitally or in analog as long as your equipment is well-grounded. The difference will come from where and how the signal is converted between digital and analog (via a DAC). It also depends on how sensitive your ears are to the quality of the audio source and the quality of the audio source. If you’re running basic streaming (like a 256 kbps AAC file) then that will be your quality bottleneck if your speakers are good quality. If you have a higher resolution file (like the CD quality or higher stuff on Apple Music) then the DAC will determine the quality of the final output. In that case the DACs in apple products are good for up to 24 bit/48khz which is more than enough for my ears and you likely don’t need more equipment besides the $10 dongles apple sells or the 3.5 mm jack in your Mac.

Hope this helps.


Using USB will convert the digital signal using the speaker’s built-in DAC, while using the analog input will convert the signal using the DAC in your Mac Mini. Easy enough to test both options to check if you can hear any difference.

The one advantage to using the “pre out” analog from the Mac would be that you can then control playback volume from the Mac. From the looks of it, the volume control of the speaker was on the back, and I didn’t see a remote in the kit.

Thank you @JohnAtl @jsingh @SpivR for sharing deeper audio knowledge which you have made easy to understand. Cheers!

@airwhale Thank you too and … are you saying that a USB connected pair of speakers could not have their volume output be controlled by our keyboard or volume menu icon? The A2+ volume is indeed in the back and also not too difficult to reach. However a front volume knob would make it easier. I may need to expand my search!

The A2+ also have a bluetooth option. Two questions if I may:

  1. How is the volume controlled with bluetooth?
  2. How does the sound quality compared to analog (3.5mm) or digital (USB)?
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I can try to answer:

  1. My experience with audio over USB on the Mac is that you can control volume using your keyboard once they’re wired in unless you use a hub that cannot work with audio over USB (these are rare). If you stream to a Bluetooth speaker then it will definitely work from speaker.
  2. again, sound quality is dependent on the quality of your source and the quality of your DAC. More than that, the room acoustics will make a huge difference there too. Assuming the source is the same, the Mac’s DAC is perfectly good for quality. I can’t tell you much about the speaker’s DAC itself but once you have the speakers in hand you can easily test this by switching between the USB in, 3.5 in, and Bluetooth source in and compare them. Like I mentioned above, the room acoustics will determine how the speakers resonate in your room and will most likely make a bigger difference than the way you connect them (although generally Bluetooth degrades the quality a bit by requiring compression vs relatively lossless wired transmission).

Another important consideration when working with lossless output from a Mac - the Mac, unlike iOS devices, does not automatically temper the output to meet the maximum output capability of a connected DAC. To make sure the Mac is outputting audio in the best quality you need to open Audio MIDI Setup and manually adjust the output bitrate and sample rate for each connected audio output.

Bluetooth will always sound worse than the analog output of the Mac or a USB audio interface.

If you are trying to decide between speakers based on the way they sound, any difference between the design/quality of the speakers themselves will have way way way more influence than whether they are connected via 3.5mm or USB.

Thanks for this - I had entirely overlooked the entire section.

I assume the bitrate/depth should match the max capacity of my DAC and that any lower bitrates will simply be passed unchanged (not upsampled by the Mac)?

Agree totally with this Kevin. Bluetooth is often fine too, unless you are in an active listening mode. For background music at lower volumes, esp. when focused on something else, it usually makes no practical difference.

Yes that is my understanding!

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Yes, I said that, didn’t I. Turns out I’m wrong - there is a setting that can be activated to control this via the Mac. (I run my own DAC/AMP with external volume control only, not considering the other option.)

Of course, the volume will max out at the level set by the volume control on the speaker itself. I suggest you start at a low level on the speaker while maxing the Mac output. Then turn up on the speaker until you reach your desired max volume in the room. Now you can reduce the volume using the keyboard or volume icon.