NOTE: I wrote this page in 2014. Here are some updates in 2023:
- I’ve read that some C-Media CM6206 devices show up in MacOS, but no sound will flow until you send them specific configuration packets. (I have not experienced this problem with the 2 devices I tested below.) The CM6206 Enabler software was developed to fix the problem, but it’s 32bit and won’t function in modern versions of MacOS. There is a 64bit update on github.
- There are reports that recent MacOS versions broke compatibility with these devices in more serious ways. In Feb 2023 I tested on an Intel iMac with MacOS Catalina (10.15.7) and an Apple Silicon Mac Studio with MacOS Monterey (12.6.3). Everything worked fine (device appeared in Sound prefs and Audio MIDI Setup, all 8 channels worked).
In 2014 I was looking for inexpensive (< $50) audio interfaces that provide 8 analog outputs for sound art installations and surround mixing in the studio. The search led me to “7.1 channel USB soundcards” based on the C-Media CM6206 chipset. These interfaces provide 2 inputs and 8 outputs and utilize the built-in Mac OS X “class driver”. It works as soon as you plug it in. No need to install any drivers and it should stay compatible with future OS versions. (Note that many marketers like to slap a “7.1 channel surround” label on interfaces that are actually 5.1 or less, touting magical driver voodoo to simulate the missing channels. Count the output jacks in the pictures to be sure of what you’re buying!)
I bought 2 different CM6206 USB interfaces in 2014, the Sabrent USB-SND8 and the Diamond XS71U. Both seem to be based on a similar reference design and both are now discontinued but you can probably find them or their siblings somewhere online. (The StarTech ICUSBAUDIO7D is based on the same chipset but I haven’t personally tested it.)
Both interfaces share these characteristics:
- They will appear in MacOS as 2 generic devices called “USB Sound Device”. (One device is the inputs. The other is the outputs.) You’ll need to combine them as an “aggregate device” if you want full duplex.
- All audio IO is on 1/8″ stereo jacks. They sound fine in my listening tests. There is no digital noise from unfiltered USB power, or audible hiss from the analog outputs.
- One exception to the above is the mic inputs. They supply low voltage “plug-in power” for condenser mics but the gain is very low and the mic preamps are so hissy that I’d hesitate to use them even for telephony.
- The Line-ins sound fine. Use Audio MIDI Setup to select which inputs you want (including SPDIF which I’ve never tried).
- They default to stereo mode every time they are plugged-in, so you need to open Apple’s Audio MIDI Setup Utility (AMS) to switch to 4, 6, or 8 channel modes.
- They have an extra output jack that is not an independent output: it mirrors the 1/2 outputs. (It’s labeled “line out” on the Sabrent and has a headphone symbol on the Diamond).
- All outputs comfortably drive a variety of headphones. If you can live without analog volume control then there’s no need for a headphone amp in most situations. (I have used this to drive 4 pairs of headphones, each with their own mix. It worked great.)
- I tried connecting 2 interfaces simultaneously. They both showed up in AMS with the same name. I combined them into an aggregate device and selected it in Reaper, but playback stopped as soon as it started. It seems like it doesn’t work. I haven’t gotten any farther than that.
- I haven’t tried S/PDIF digital IO, sorry.
Diamond XS71U details:
I heartily recommend this one. It is made of regular shiny plastic, not the Sabrent’s gross sticky smelly stuff, and the channels aren’t routed backwards like the Sabrent (always a plus!)
Mic Input:
It has 1 stereo mic jack with terrible sound quality.
Line Input:
The stereo line input sounds great.
Output Channel mapping: (according to the router in Reaper)
| Channel Mode in Audio MIDI Setup |
Labels printed on 1/8″ jacks… | |||
| F-out | SS-out | BS-out | C/B | |
| 2 Channel | 1/2 | |||
| 4 Channel | 1/2 | 3/4 | ||
| 6 Channel | 1/2 | 5/6 | 3/4 | |
| 8 Channel | 1/2 | 7/8 | 5/6 | 3/4 |
Sabrent USB-SND8 details:
It smells like a dollar store! It’s got that rubberized matte plastic finish that will get sticky and gross after a few years. For me this is reason enough to avoid it.
Mic Input:
It has 2 mono mic jacks with terrible sound quality. They are labeled backwards (Mic 2 is Left, Mic 1 is Right).
Line Input:
The stereo line input sounds great, but it’s also backwards. (Left and Right are swapped)
Output Channel mapping: (according to the router in Reaper)
** Note the backwards panning on the C/Sub jack! So much backwards stuff on this box!
| Channel Mode in Audio MIDI Setup |
Labels printed on 1/8″ jacks… | |||
| Front L/R | Side L/R | Rear L/R | C/Sub | |
| 2 Channel | 1/2 | |||
| 4 Channel | 1/2 | 3/4 | ||
| 6 Channel | 1/2 | 5/6 | 4/3 | |
| 8 Channel | 1/2 | 7/8 | 5/6 | 4/3 |
Further Research
Improve the bass response (on 5.1 version, but PCB layout should be very similar): C-MEDIA CM6206 5.1 USB Audio Sound Card Line-In & Line-Out Bass Extension Low Frequency Response Upgrade
