My system consists of a 2011 iMac running Mavericks, and using an external audio interface (iConnectAudio4+) along with a Bluetooth speaker and Airfoil to create a "surround" effect for music while I'm working.

The issue is specific to SoundFlower, which I must use or I can't adjust the computer volume at all (volume control gets greyed out). My routing for this setup is as follows:

Mac Audio Output > SoundFlower > iConnectAudio4+

Airfoil's audio source is typically iTunes and its speakers are the computer, and the Bluetooth speaker. When I have this set up, everything works fine, except that periodically audio will begin to drift and sounds a lot like a warped cassette tape. It's very noticeable especially on any sort of sustained notes (pianos, voice, etc.).

If I remove SoundFlower from the equation and simply route System audio direct to the iConnectAudio4+, the problem goes away but I am no longer able to adjust the Mac audio levels via the OS.

In my experience getting this to work, I have to use Airfoil because any other solution such as simply creating a multi-output device of the audio interface and BT speaker, results in a significant and non-adjustable delay between the two. Airfoil allows for dialing in the latency so that everything is in near perfect sync around me.

My question could be seen as 2 part:

  1. Is there a way to use this setup as I have described but eliminate the audio warping?
  2. Is there a different way to set my system up which would give me the same end result (including ability to adjust Mac volume via the OS) but without audio warping?
  • Which version of Soundflower? There are a few kicking around, by different authors. Rogue Amoeba I think even gave up hosting the old Cycling74 version now. Frankly, it's been flaky since about Mavericks - I gave up on it a long time ago. Audio Hijack or Loopback (both Rogue Amoeba ) would be modern [paid] alternatives.
    – Tetsujin
    Commented Jan 1, 2017 at 10:00
  • I just gave Loopback a try but unfortunately it disables the Mac volume control when passing system audio through it. This was actually the only reason I used SoundFlower, it did not have this issue.
    – JVC
    Commented Jan 1, 2017 at 17:04
  • Hmmm... idk then. I hadn't realised it did that; my rig has a hardware volume control so I never adjust at the Mac itself & actually I have system audio [beeps etc] always routed to the Mac's speaker, never through my audio rig.
    – Tetsujin
    Commented Jan 1, 2017 at 17:23
  • I've got an email in to Rogue Amoeba asking about this issue, will update with whatever I find out from them.
    – JVC
    Commented Jan 1, 2017 at 17:24
  • RA are usually pretty good at responding, so keep us updated. Make sure I get pinged by the system by putting @Myname [it won't let me put my own name in as an example] somewhere in the response.
    – Tetsujin
    Commented Jan 1, 2017 at 17:27

1 Answer 1


Apparently the issue may lie in SoundFlowerBed, not SoundFlower itself. But since SFB is an abandoned project... it is unlikely to ever be made more robust.

Fortunately I think I've found a solution, which is Sound Siphon. I'm using it exactly as I would have with SoundFlower - routing my system sound and AirFoil to Sound Siphon, and sending Sound Siphon out to my audio interface.

Seems to be working perfectly, no audio warbling, and I can still adjust my overall system volume with the usual OS controls. Plus, the demo version allows unlimited use of System Audio, which is all I was after... so this solution is even free!

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