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abduct
Apprentice
Joined: 19 Mar 2015
Posts: 215
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 Posted: Sun Apr 29, 2018 9:08 pm Post subject: Alsa support for 2.1 channel HP laptop |
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I am using a HP Envy-4 (https://support.hp.com/us-en/document/c03377593) which supposedly has 2 speakers (left and right) and a "Beats" subwoofer.
I was poking around `amixer' to add some more blocks to my bar for X11 and I noticed that amixer is in mono mode:
| Code: | $ amixer sget Master
Simple mixer control 'Master',0
Capabilities: pvolume pvolume-joined pswitch pswitch-joined
Playback channels: Mono
Limits: Playback 0 - 127
Mono: Playback 109 [86%] [-13.50dB] [on]
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On this discovery I went to `speaker-test` and ran it with the flags `-t wav -c 3` to see what was happening. The results were that it would play "front left", "front right" and then skip the subwoofer:
| Code: | $ speaker-test -t wav -c 3
speaker-test 1.1.6
Playback device is default
Stream parameters are 48000Hz, S16_LE, 3 channels
WAV file(s)
Rate set to 48000Hz (requested 48000Hz)
Buffer size range from 2048 to 16384
Period size range from 1024 to 1024
Using max buffer size 16384
Periods = 4
was set period_size = 1024
was set buffer_size = 16384
0 - Front Left
1 - Front Right
2 - Unused
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You can audibly hear the two separate speakers on the laptop.
So my question is:
Is alsa really outputting in mono, and is it possible to enable the built in sub woofer. To be honest I did not even know there was a sub woofer present as I have never heard it (the sound is really quite tinny).
Is there a way to test and trouble shoot this?
Edit:: Also is there a way to get the levels from alsamixer for the Master channel? Parsing and comparing `amixer sget Master` shows a vast difference between the alsamixer level and what the amixer command outputs. For example at the moment alsamixer states the Master channel is at 58, but amixer states that it is 86%. I prefer the alsamixer values.
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abduct
Apprentice
Joined: 19 Mar 2015
Posts: 215
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| Posted: Sun May 06, 2018 6:09 pm Post subject: |
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After some researching it turns out these `beats' 2.1 speaker setup in laptops are not supported under linux due to beats not releasing firmware for its amplifiers or something of the sort. There has been some long winded work arounds involving pulse and some patches but I don't think it is worth the time to jump through the hoops to get the subwoofer working, let along being forced to use pulse to get it to work.
If anyone has any ideas that would get it to work using alsa let me know. |
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eccerr0r
Watchman
Joined: 01 Jul 2004
Posts: 9679
Location: almost Mile High in the USA
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| Posted: Sun May 06, 2018 6:58 pm Post subject: |
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I don't have an ear for sound so I can't tell of my Envy4 is really using its supposed subwoofer. On the other hand, the speakers seem simply louder in windows.
I am running PA however. There was a utility to "reconfigure" connections but it didn't seem to affect the sound.
My laptop is reporting stereo sound and not mono. Playing speaker test does distinguish left and right, but sending output to the supposed LFE port does not seem to produce any sound. Unsure if there's a LPF that causes LFE to ignore voice for the most part, however.
_________________
Intel Core i7 2700K/Radeon R7 250/24GB DDR3/256GB SSD
What am I supposed watching? |
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