How to increase sound volume on eMac P69 running FreeBSD 10.3?

I've got FreeBSD 10.3 (PowerPC) installed on eMac P69. I'm using MPlayer to test loudness. I already use -af volume=10:1-like options but they tend to distort sound pretty quickly + it is not really a solution. From what I read online I should be able to change volume using systcl hw.snd.vpc_0db or mixer(8). Unfortunately: - systcl hw.snd.vpc_0d=45 is too quiet - systcl hw.snd.vpc_0d=10 is quite ok but still it could/should go louder - systcl hw.snd.vpc_0d=1 is distorted and really not that louder than 10 - mixer returns: > mixer: /dev/mixer: No such file or directory From what I remember when this machine still had Mac OS X its speakers were way louder comparing to what I get on FreeBSD. ### Questions 1. Why is /dev/mixer missing? 2. Is there any other way to increase speaker volume? ### Other details They might come in handy: - _/boot/loader.conf_ sound_load="YES" snd_driver_load="YES" - I tried kldload snd_hda but it didn't help. - kldload snd_driver results in > kldload: can't load snd_driver: No such file or directory Also, there are interesting messages in the system message buffer displayed with dmesg: > link_elf: symbol isa_dma_release undefined > KLD snd_driver.ko: depends on snd_sb8 - not available or version mismatch