Speakers on iMac sound like a cheap cellphone

[andinus]

Found this related thread: https://mailing.openbsd.misc.narkive...penbsd-on-imac

> high pitched and a narrow with a narrow bandwith

> 1) The sound from the speakers sound like they come from a cheap cellphone.
> 2) When plugging in headphones the main speakers are muted, but there's
> no sound from the headphones themselves. I tried setting sndiod to
> channels 0:1 (default - main speakers), 2:3 (main speakers) and 4:5 (no
> sound)

^ This describes it.

mixerctl -v:
inputs.dac-2:3_mute=off [ off on ]
inputs.dac-2:3=126,126
inputs.dac-0:1_mute=off [ off on ]
inputs.dac-0:1=126,126
record.adc-2:3_source=line-in [ line-in ]
record.adc-2:3_mute=off [ off on ]
record.adc-2:3=124,124
record.adc-0:1_source=mic [ mic ]
record.adc-0:1_mute=off [ off on ]
record.adc-0:1=124,124
record.dig-adc-0:1_sou=SPDIF-in [ SPDIF-in ]
outputs.spkr_source=dac-2:3 [ dac-2:3 ]
outputs.spkr_boost=on [ off on ]
outputs.hp_source=dac-0:1 [ dac-0:1 ]
outputs.spkr2_source= [ ]
inputs.line-in=85,85
inputs.mic=85,85
outputs.mic_dir=input-vr80 [ none input input-vr0 input-vr50 input-vr80 ]
outputs.SPDIF_source=dig-dac-0:1 [ dig-dac-0:1 ]
outputs.hp_sense=unplugged [ unplugged plugged ]
outputs.line-in_sense=unplugged [ unplugged plugged ]
outputs.SPDIF-in_sense=unplugged [ unplugged plugged ]
outputs.spkr_muters=hp { hp }
outputs.master=126,126
outputs.master.mute=off [ off on ]
outputs.master.slaves=dac-2:3,dac-0:1 { dac-2:3 dac-0:1 }
record.volume=124,124
record.volume.mute=off [ off on ]
record.volume.slaves=adc-2:3,adc-0:1 { adc-2:3 adc-0:1 line-in mic }
outputs.mode=analog [ analog digital ]
record.mode=analog [ analog digital ]
record.enable=sysctl [ off on sysctl ]

pcidump:
0:27:0: Intel 6 Series HD Audio
[...]
1:0:1: ATI Radeon HD 6670 Audio

pcidump -v:
0:27:0: Intel 6 Series HD Audio
0x0000: Vendor ID: 8086, Product ID: 1c20
0x0004: Command: 0006, Status: 0010
0x0008: Class: 04 (unknown), Subclass: 03 (unknown),
Interface: 00, Revision: 05
0x000c: BIST: 00, Header Type: 00, Latency Timer: 00,
Cache Line Size: 40
0x0010: BAR mem 64bit addr: 0x00000000a8900000/0x00004000
0x0018: BAR empty (00000000)
0x001c: BAR empty (00000000)
0x0020: BAR empty (00000000)
0x0024: BAR empty (00000000)
0x0028: Cardbus CIS: 00000000
0x002c: Subsystem Vendor ID: 8086 Product ID: 7270
0x0030: Expansion ROM Base Address: 00000000
0x0038: 00000000
0x003c: Interrupt Pin: 01 Line: 00 Min Gnt: 00 Max Lat: 00
0x0050: Capability 0x01: Power Management
State: D0
0x0060: Capability 0x05: Message Signalled Interrupts (MSI)
Enabled: yes
0x0070: Capability 0x10: PCI Express
Max Payload Size: 128 / 128 bytes
Max Read Request Size: 128 bytes
0x0100: Enhanced Capability 0x02: Virtual Channel Capability
0:27:0: Intel 6 Series HD Audio
0x0000: Vendor ID: 8086, Product ID: 1c20
0x0004: Command: 0006, Status: 0010
0x0008: Class: 04 (unknown), Subclass: 03 (unknown),
Interface: 00, Revision: 05
0x000c: BIST: 00, Header Type: 00, Latency Timer: 00,
Cache Line Size: 40
0x0010: BAR mem 64bit addr: 0x00000000a8900000/0x00004000
0x0018: BAR empty (00000000)
0x001c: BAR empty (00000000)
0x0020: BAR empty (00000000)
0x0024: BAR empty (00000000)
0x0028: Cardbus CIS: 00000000
0x002c: Subsystem Vendor ID: 8086 Product ID: 7270
0x0030: Expansion ROM Base Address: 00000000
0x0038: 00000000
0x003c: Interrupt Pin: 01 Line: 00 Min Gnt: 00 Max Lat: 00
0x0050: Capability 0x01: Power Management
State: D0
0x0060: Capability 0x05: Message Signalled Interrupts (MSI)
Enabled: yes
0x0070: Capability 0x10: PCI Express
Max Payload Size: 128 / 128 bytes
Max Read Request Size: 128 bytes
0x0100: Enhanced Capability 0x02: Virtual Channel Capability
0x0130: Enhanced Capability 0x05: Root Complex Link Declaration 0x0130: Enhanced Capability 0x05: Root Complex Link Declaration
[...]
1:0:1: ATI Radeon HD 6670 Audio
0x0000: Vendor ID: 1002, Product ID: aa90
0x0004: Command: 0006, Status: 0010
0x0008: Class: 04 (unknown), Subclass: 03 (unknown),
Interface: 00, Revision: 00
0x000c: BIST: 00, Header Type: 80, Latency Timer: 00,
Cache Line Size: 40
0x0010: BAR mem 64bit addr: 0x00000000a8840000/0x00004000
0x0018: BAR empty (00000000)
0x001c: BAR empty (00000000)
0x0020: BAR empty (00000000)
0x0024: BAR empty (00000000)
0x0028: Cardbus CIS: 00000000
0x002c: Subsystem Vendor ID: 106b Product ID: aa90
0x0030: Expansion ROM Base Address: 00000000
0x0038: 00000000
0x003c: Interrupt Pin: 02 Line: 00 Min Gnt: 00 Max Lat: 00
0x0050: Capability 0x01: Power Management
State: D0
0x0058: Capability 0x10: PCI Express
Max Payload Size: 128 / 256 bytes
Max Read Request Size: 512 bytes
Link Speed: 5.0 / 5.0 GT/s
Link Width: x16 / x16
0x0100: Enhanced Capability 0x0b: Vendor-Specific
0x0150: Enhanced Capability 0x01: Advanced Error Reporting
0x00a0: Capability 0x05: Message Signalled Interrupts (MSI)
Enabled: no


Looks like on pulseaudio changing some option to "surround" fixes it.

[jggimi]

The OP for your link is OpenBSD developer martijn@. You might try reaching out to him directly regarding his iMac audio experiences, in the event he found a solution in the last six years.

[andinus]

I did try sending them an email earlier (from the list) but looks like the account doesn't exist anymore.

Do you know how should I contact them? (@openbsd address?)

[jggimi]

Yes.

[andinus]

Looks like they don't use the device anymore and didn't find any fix when they did.

I actually booted up Fedora on this and "Surround" made it sound like cheap cellphone, keeping it "Stereo" worked fine.