Surround (garbled) sound played to headset port

When using analog headset plugged into the audio port, sound is mono and processed so voice is silenced

If played to speakers it works fine

After killing pulseaudio at a bit of trouble, once can test using:

speaker-test --channels 2 --nloops 1 --device plughw:PCH,0

which works fine for internal speakers, but is mono for headset
If you watch youtube video, dialog is suppressed while other sounds may work

This can be somewhat patched by going into alsamixer and set the left and right Headset channels to different levels using q/z and e/c keys

This appears to be a bug in snd_hda_intel

MacBook Air 2011
MacBookAir4,1
MacBook Air (11-inch, Mid 2011)
chip: Cirrus 4206BCNZ

0:1b.0 Audio device [0403]: Intel Corporation 6 Series/C200 Series Chipset Family High Definition Audio Controller [8086:1c20] (rev 05)
        Subsystem: Intel Corporation Apple MacBookPro8,2 [Core i7, 15", 2011]
 [8086:7270]
        Kernel driver in use: snd_hda_intel
        Kernel modules: snd_hda_intel

ProblemType: Bug
DistroRelease: Ubuntu 17.04
Package: linux-image-4.10.0-22-generic 4.10.0-22.24
ProcVersionSignature: Ubuntu 4.10.0-22.24-generic 4.10.15
Uname: Linux 4.10.0-22-generic x86_64
ApportVersion: 2.20.4-0ubuntu4.1
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/pcmC0D0c: foxyboy 21762 F...m pulseaudio
 /dev/snd/controlC0: foxyboy 21762 F.... pulseaudio
CurrentDesktop: GNOME
Date: Mon Jul 3 23:18:14 2017
HibernationDevice: RESUME=/dev/mapper/vg0-swap
InstallationDate: Installed on 2015-10-28 (614 days ago)
InstallationMedia: Ubuntu-Server 15.10 "Wily Werewolf" - Release amd64 (20151021)
MachineType: Apple Inc. MacBookAir4,1
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-4.10.0-22-generic.efi.signed root=/dev/mapper/vg0-rfs ro
RelatedPackageVersions:
 linux-restricted-modules-4.10.0-22-generic N/A
 linux-backports-modules-4.10.0-22-generic N/A
 linux-firmware 1.164.1
SourcePackage: linux
UpgradeStatus: Upgraded to zesty on 2017-04-09 (86 days ago)
dmi.bios.date: 06/08/2015
dmi.bios.vendor: Apple Inc.
dmi.bios.version: MBA41.88Z.0077.B12.1506081728
dmi.board.asset.tag: Base Board Asset Tag#
dmi.board.name: Mac-C08A6BB70A942AC2
dmi.board.vendor: Apple Inc.
dmi.board.version: MacBookAir4,1
dmi.chassis.type: 10
dmi.chassis.vendor: Apple Inc.
dmi.chassis.version: Mac-C08A6BB70A942AC2
dmi.modalias: dmi:bvnAppleInc.:bvrMBA41.88Z.0077.B12.1506081728:bd06/08/2015:svnAppleInc.:pnMacBookAir4,1:pvr1.0:rvnAppleInc.:rnMac-C08A6BB70A942AC2:rvrMacBookAir4,1:cvnAppleInc.:ct10:cvrMac-C08A6BB70A942AC2:
dmi.product.name: MacBookAir4,1
dmi.product.version: 1.0
dmi.sys.vendor: Apple Inc.