Getting high quality audio from 2017 iMac

[carbontune]

Aside from the built-in speakers and the headphones socket, it appears that there is no other analogue or digital sound output on a 2017 iMac. Is there a way to get a digital bitstream for outboard DAC processing from the iMac? Additionally, is the 3.5mm audio output an amplified headphones output or can it double as a line level output?

 

[BrianBaughn]

You'd have to get a USB or Thunderbolt audio device that has your desired digital output port to get a direct digital stream to whatever outboard DAC you're considering.

 

[Fishrrman]

"Is there a way to get a digital bitstream for outboard DAC processing from the iMac?"

Yes.
Through the USB3 port or thunderbolt port.

That's the answer.
Now you have to start searching for the device that suits your needs.
I'd suggest using USB.

 

[carbontune]

I woke up halfway through the night to look into this! There's the Audioquest Dragonfly Black or Red that seems to be highly rated as a USB DAC/headphone amp. With an outboard DAC I'd need a set of speakers. I've also found the Kef Egg active speakers that seem to be quite highly rated.

I'm also going to look at traditional bookshelf-style active speakers. I'd want a very significant improvement in sound quality over the iMac built-in speakers.

 

[J.Gallardo]

I woke up halfway through the night to look into this! There's the Audioquest Dragonfly Black or Red that seems to be highly rated as a USB DAC/headphone amp. With an outboard DAC I'd need a set of speakers. I've also found the Kef Egg active speakers that seem to be quite highly rated.

I'm also going to look at traditional bookshelf-style active speakers. I'd want a very significant improvement in sound quality over the iMac built-in speakers.

Yes. Apple's internal DAC is easy to beat. USB is the way to go; and you'll have an added sound output.
I'm quite happy with a Dragonfly Red in my iMac set-up. I've configured "MIDI SetUp Utility" so systems sounds are delivered through internal speakers. All other sound goes usb-Dragonfly out (this DAC sounds terrific), to my traditional & vintage Hi-Fi deck & speakers (aux-in).
I bought the Dragonfly due to its small size, as I wanted to use it with my iPhone (I've ended using a dedicated HiRes DAP).
If I were to buy an external DAC for my desktop today, I would consider other products as well. You pay an extra for portability, and can get something even better for same price.
(I'm not an expert, but remember being tempted by some "Cambridge Audio" DACs... )

 

[carbontune]

Yes. Apple's internal DAC is easy to beat. USB is the way to go; and you'll have an added sound output.
I'm quite happy with a Dragonfly Red in my iMac set-up. I've configured "MIDI SetUp Utility" so systems sounds are delivered through internal speakers. All other sound goes usb-Dragonfly out (this DAC sounds terrific), to my traditional & vintage Hi-Fi deck & speakers (aux-in).
I bought the Dragonfly due to its small size, as I wanted to use it with my iPhone (I've ended using a dedicated HiRes DAP).
If I were to buy an external DAC for my desktop today, I would consider other products as well. You pay an extra for portability, and can get something even better for same price.
(I'm not an expert, but remember being tempted by some "Cambridge Audio" DACs... )

I spoke to a UK dealer for the Audioquest Dragonfly but he couldn't answer some specific questions about it. Does it have a line out or a headphone out?

I might look at other USB DACs as, you're right, some of the cost of the Dragonfly is related to the miniaturisation of the product. Cambridge Audio is a British company so I'll take a look at their DACs. They have a computer-oriented USB DAC called the DacMagic XS that is priced at 100GPB retail which is quite a bit less than the Dragonfly Red:

https://www.cambridgeaudio.com/gbr/en/products/hifi-and-home-cinema/dacmagic-xs

The DacMagic 100 isn't portable but appears to be a much better quality DAC than the XS:

https://www.cambridgeaudio.com/gbr/en/products/hifi-and-home-cinema/dacmagic-100

PS: thanks for the tip about using 'MIDI Setup Utility' to reroute system sounds to the iMac's internal speakers.

 

[J.Gallardo]

I spoke to a UK dealer for the Audioquest Dragonfly but he couldn't answer some specific questions about it. Does it have a line out or a headphone out?

I might look at other USB DACs as, you're right, some of the cost of the Dragonfly is related to the miniaturisation of the product. Cambridge Audio is a British company so I'll take a look at their DACs. They have a computer-oriented USB DAC called the DacMagic XS that is priced at 100GPB retail which is quite a bit less than the Dragonfly Red:

https://www.cambridgeaudio.com/gbr/en/products/hifi-and-home-cinema/dacmagic-xs

The DacMagic 100 isn't portable but appears to be a much better quality DAC than the XS:

https://www.cambridgeaudio.com/gbr/en/products/hifi-and-home-cinema/dacmagic-100

PS: thanks for the tip about using 'MIDI Setup Utility' to reroute system sounds to the iMac's internal speakers.

Of course, we're talking about cheap DACs... But I think the step from built-in-dac is substantial even with a well chosen affordable DAC.
I suppose Dragonfly gives a headphone-out (I use it as a line-out, though). The good thing about a so well integrated gadget is no-cable fuss and instant plug&play (some desktop DACs need aux power supply). You loose info about audio playing (I can't see light color in Dragonfly; I don't care), and perhaps a more accessible audio-plug could be important (I never use headphones with iMac).
At the end, quality of DAC sound depends on your taste, but I have also a FiiO QII and audio quality seems inferior to me.
Every brand (and proper DAC chips) has its own sound signature... that you may like or not. Anyhow, it will surely be much better than provided quality. You'll get a much more detailed sound.
After my rendition to HiRes audio (for favourite music; I listen to AppleMusic also) I have purchased a dedicated DAP, as I told (expecting parcel in a few days). Is good to know that most of these devices that have pretty good DACs in them can also be used as external USB DAC for your mac...

 

[josduc]

IMHO it's a matter of taste. I've owned iMacs and a MBP, and now a 2017 iMac again. Had a Little Dot DAC hooked up to it. Maybe it was an upgrade for the older iMacs I owned, but the 2010 MBP and now the 2017 iMac offer an output quality I find very hard to distinguish from an external DAC.

I'm not looking for warmer or richer sound. I want it to sound as close as the artist intended. So I spent quite some time figuring out what to do. I realized the biggest improvement for me was upgrading the speakers. I now have Adam A5X monitors, just plugged in the iMac with an analogue cable. Unbelievable difference. I might upgrade this set by adding an Adam Sub8. I have to make clear I listen to music sitting at my desk, so near-field.

There is a downside however. Well maybe two: all other speakers sound like s#%t now, and if you listen to a song that is recorded at a bad quality it'll not be covered up. It will sound awful. And yes, even FLAC, CD or HiRES audio can be recorded or mixed really bad.

 

[J.Gallardo]

IMHO it's a matter of taste. I've owned iMacs and a MBP, and now a 2017 iMac again. Had a Little Dot DAC hooked up to it. Maybe it was an upgrade for the older iMacs I owned, but the 2010 MBP and now the 2017 iMac offer an output quality I find very hard to distinguish from an external DAC.

I'm not looking for warmer or richer sound. I want it to sound as close as the artist intended. So I spent quite some time figuring out what to do. I realized the biggest improvement for me was upgrading the speakers. I now have Adam A5X monitors, just plugged in the iMac with an analogue cable. Unbelievable difference. I might upgrade this set by adding an Adam Sub8. I have to make clear I listen to music sitting at my desk, so near-field.

There is a downside however. Well maybe two: all other speakers sound like s#%t now, and if you listen to a song that is recorded at a bad quality it'll not be covered up. It will sound awful. And yes, even FLAC, CD or HiRES audio can be recorded or mixed really bad.

I agree. And perhaps, dollar per dollar, investing in good speakers is the real upgrade.
I've being reading technical reviews since first Apple sound devices (and owned a few) and they always supported my subjective opinion: yes, Apple products have had nice sound always, comparing with other brands.
I would say a DAC is luxury, but good speakers are essential.
But, now that you have an ideal pair of speakers (as I do)... how could you get higher quality audio from your mac?

 

[josduc]

Well, that would indeed be by adding a DAC. But it would be quite a search to find one that doesn't "color" the sound. Another very small upgrade would be to go from RCA connectors to XLR. But that would require a DAC, or USB audio interface, with XLR outputs.

 

[Peter_M]

I use Focusrite Clarett 2pre, and compared to my iMac Pro's DAC played through a pair of EVE SC205 studio monitors, there is an obvious and easily heard improvement in sound quality. Clarett 2pre uses mic preamps, so it might not be your first choice. If you're gonna get an external sound card, get something with good quality. A cheap/lower mid-range external DAC isn't gonna be enough of a difference to be worth the hassle IMO.

 

[interstella]

There is a downside however. Well maybe two: all other speakers sound like s#%t now, and if you listen to a song that is recorded at a bad quality it'll not be covered up. It will sound awful. And yes, even FLAC, CD or HiRES audio can be recorded or mixed really bad.

Listening to anything by Oasis, Flaming Lips or Snow Patrol will confirm that you're 100% correct! Horrendously over-compressed and so loud that turning the volume up to 3 will blow your speaker cones!

 

[josduc]

Oh man, Oasis' (What's the Story) Morning Glory. Where do I start. Such a shame. There is however a remastered version of that album. It's better, not perfect.

 

[carbontune]

Just on a general note, I listened to one of my favourite radio stations on YouTube yesterday during a live broadcast and the sound from the built-in speakers was okay for an all-in-one computer. By okay I mean that it was not tiring to listen to.

However, I think my longer term project will be to use an outboard DAC with active speakers. Having decluttered my tiny computer room at home, anything that can be hidden away or saves space will be on my wish list.

 

[josduc]

Just on a general note, I listened to one of my favourite radio stations on YouTube yesterday during a live broadcast and the sound from the built-in speakers was okay for an all-in-one computer. By okay I mean that it was not tiring to listen to.

However, I think my longer term project will be to use an outboard DAC with active speakers. Having decluttered my tiny computer room at home, anything that can be hidden away or saves space will be on my wish list.

Try to get a set of second hand Adam Artist 5 speakers. I have them in the living room. Has the DAC built in, connects with USB. Keeps your setup very minimal and they sound pretty close to my Adam A5X set.

 

[carbontune]

Try to get a set of second hand Adam Artist 5 speakers. I have them in the living room. Has the DAC built in, connects with USB. Keeps your setup very minimal and they sound pretty close to my Adam A5X set.

Thanks for the suggestions - both the Adam Artist 5 (and 3 models), plus the A5X look like exactly what I'm looking for! The white models with the desk stand look amazing (I'm a sucker for aesthetics and like things to look nice as well as performing well).

One other issue that I'm trying to address is lag with Airplay. I have several Audyssey Lower East Coast Audio Dock Air speakers in different rooms and these sound very, very nice with a rich, warm bass-heavy sound. However, they are far from audiophile speakers, but the sound is pleasing and they are compact and wireless. They're great for playing iTunes music through, but listening to video is a no-no due to the several seconds of lag. One disadvantage of these speakers is that, due to their form factor being a single unit, they are designed to fill a room with sound so there's not much perception of a soundstage at all. Hence, my search for an alternative sound system for the iMac.

Do USB active speakers suffer from lag when watching a vide as my Airplay speakers do?

 

[josduc]

Never noticed lag, should be fine.

 

[J.Gallardo]

Never used Airplay to watch movies, but I can figure a quick patch for your problem:
A few players (as VLC) allow you to adjust image/video timing. Make soundtrack “sooner” and try to find the spot where the stream works.
(I thought Airplay lag would affect image & sound...)

 

[carbontune]

I found an old headphones amp/DAC in a storage box at home. I remember buying it around a decade ago and it was quite highly regarded then.

It's an entry-level DAC with up to 24-bit/96K conversion. Unfortunately, it only has Toslink and Coaxial digital inputs and does not have a USB audio inout. To use this DAC, which is obviously a no-cost option to me, I'd have to get a USB to Toslink adapter. I'd then have to connect up the adapter output to the Beresford DAC and then feed the analogue output of the DAC to a set of (non-DAC) active speakers. From a cabling point of view, this is going to be quite ugly.

The neatest solution is to get a set of active speakers with a built in USB DAC.

 

[carbontune]

Does anybody know whether this Apple website is showing the wrong information for a 2017 iMac? It seems to suggest that the headphone jack supports a digital audio output too, as per earlier iMac:

https://support.apple.com/en-gb/HT204392#2017

---------------------------------------------------------------------------------------

Rear panel
3.5mm headphone jack

The headphone output supports a stereo data stream at bit depths of 16, 20, or 24 bits per sample and at sample rates of 44.1 kHz or 48 kHz. The headphone output volume can be adjusted from 0.0 dB to -43.0 dB.

During playback of a 1 kHz sine wave at -3 dBFS voltage level, 24-bit sample depth, 44.1 kHz output sample rate, 100 k load (unless otherwise specified), the audio output has the following nominal specifications:

• Jack type: 3.5 mm (1/8-inch) stereo combo
• Maximum output voltage: 1.4 VRMS (+5.15 dBu)
• Output impedance: <24 ohms
• Frequency response: 20 Hz to 20 kHz, +0.5 dB/-3 dB
• Signal-to-noise ratio (SNR): >90 dB
• Total harmonic distortion + noise (THD+N): <-80 dB (0.007%)
• Channel separation: >85 dB

---------------------------------------------------------------------------------------

It seems to suggest that a digital audio output exists, albeit at only up to 48kHz sampling rate.

 

[J.Gallardo]

Does anybody know whether this Apple website is showing the wrong information for a 2017 iMac? It seems to suggest that the headphone jack supports a digital audio output too, as per earlier iMac:

https://support.apple.com/en-gb/HT204392#2017

---------------------------------------------------------------------------------------

Rear panel
3.5mm headphone jack

The headphone output supports a stereo data stream at bit depths of 16, 20, or 24 bits per sample and at sample rates of 44.1 kHz or 48 kHz. The headphone output volume can be adjusted from 0.0 dB to -43.0 dB.

During playback of a 1 kHz sine wave at -3 dBFS voltage level, 24-bit sample depth, 44.1 kHz output sample rate, 100 k load (unless otherwise specified), the audio output has the following nominal specifications:

• Jack type: 3.5 mm (1/8-inch) stereo combo
• Maximum output voltage: 1.4 VRMS (+5.15 dBu)
• Output impedance: <24 ohms
• Frequency response: 20 Hz to 20 kHz, +0.5 dB/-3 dB
• Signal-to-noise ratio (SNR): >90 dB
• Total harmonic distortion + noise (THD+N): <-80 dB (0.007%)
• Channel separation: >85 dB

---------------------------------------------------------------------------------------

It seems to suggest that a digital audio output exists, albeit at only up to 48kHz sampling rate.

...Sure. "A digital audio output exists", as that's what the computer DAC is able to work with: "a stereo data stream at bit depths of 16, 20, or 24 bits per sample and at sample rates of 44.1 kHz or 48 kHz" (with usb-plugged DAC I'm listening to FLAC 24bit/96kHz right now). Then, DAC converts to analog to the headphone output (headphone output volume can be adjusted from 0.0 dB to -43.0 dB).
After that, the nominal specifications of analog sound follow. And, as said, Apple's internal DAC is pretty good.
I'm not a sound engineer, but I think when we talk bits/kHz is digital stream. When we change to decibels, we're going analog.

 

[carbontune]

...Sure. "A digital audio output exists", as that's what the computer DAC is able to work with: "a stereo data stream at bit depths of 16, 20, or 24 bits per sample and at sample rates of 44.1 kHz or 48 kHz" (with usb-plugged DAC I'm listening to FLAC 24bit/96kHz right now). Then, DAC converts to analog to the headphone output (headphone output volume can be adjusted from 0.0 dB to -43.0 dB).
After that, the nominal specifications of analog sound follow. And, as said, Apple's internal DAC is pretty good.
I'm not a sound engineer, but I think when we talk bits/kHz is digital stream. When we change to decibels, we're going analog.

It seems to be a coaxial digital output on the 3.5mm headphones socket rather than an optical out of previous generations of iMac. I would say that the onboard DAC in a 2017 iMac is quite poor since the maximum bitrate is just 48kHz.

 

[J.Gallardo]

44.1 kHz is CD quality... Not so bad. Other specs are similar to known brands, medium price players (HiFi sets, for example).
Be sure you'll need very good speakers (and amp) to tell the difference (but you will).

 

[carbontune]

44.1 kHz is CD quality... Not so bad. Other specs are similar to known brands, medium price players (HiFi sets, for example).
Be sure you'll need very good speakers (and amp) to tell the difference (but you will).

I've got a DAC and studio monitors arriving this week so it'll solve my Airplay speakers lag issue (with video) and hopefully get some better sound to listen to my lossless (CD) files to.

I had a fairly small budget for DAC and speakers so opted for an SMSL M6 DAC and a pair of KRK Rokit RP5 G3 studio monitors - both of those I bought for a fairly good discount. I'm hoping it'll all match up. The DAC has a USB input so that was the prime requirement.

 

[theluggage]

I'm not looking for warmer or richer sound. I want it to sound as close as the artist intended.

Reality check: in the modern world of recorded music, the artist (or, rather, the sound engineer who mastered the artist's work) probably intended the sound to be heard on regular earpods or cheap'n'cheerful consumer audio speakers in a noisy environment - and liberally applied EQ, effects and analog compression accordingly.

As you've found, If you switch from regular 'consumer' speakers to semi-decent "monitor" speakers (which aim for a flat 'uncoloured' response) the main effect can just be to hear all the faults in the recording...

It seems to be a coaxial digital output on the 3.5mm headphones socket rather than an optical out of previous generations of iMac. I would say that the onboard DAC in a 2017 iMac is quite poor since the maximum bitrate is just 48kHz.

No - its just an analog output. The specs are confusing but I think they're just referring to the internal DAC used to generate the analog signal. There's no mention of "S/PDIF" which would specify a digital output format (either optical or co-ax). Thats a pain in the backside if you've got old but perfectly good SPDIF kit, but most new products are using YUSB, Thunderbolt or (for A/V stuff like surround systems) HDMI.

Note that the bitrate isn't the ultimate measure of DAC "quality" - an "audiophile" DAC will offer better precision conversion, better filters and other analog components etc. plus, possibly, things like balanced speaker outputs (for lower noise/interference). Realistically, there's probably no advantage to anything more than CD-quality 44.1kHz/16 bit for listening to pre-recorded material - the advantage of higher rates & resolutions is to provide extra "headroom" for production where samples are going to be amplified, compressed, expanded, mixed, sped up, processed and re-re-re-sampled causing otherwise inaudible "artefacts" to accumulate and become magnified.