Re: kern/51784: "Synthesized" speaker hums

[Nathanial Sloss <nat%netbsd.org@localhost>]

Hi,

I've just finished a better implemetation of audiobell that should have little 
to no hum.  The probelm with the existing audiobell.c is that the maximum bell 
pitch is just 4 kHz with the patch it would be 22 kHz.

The resolution of the data used to generate the sine wave has been increased 
from 65 bytes to 2049 bytes, as the original 65 byte version genetated a 
rather square-ish sinewave at some frequencies and the hum would be a 
harminic.

The hires version generates a better looking sine wave.

To use apply this patch:
ftp.netbsd.org/pub/NetBSD/misc/nat/hiresbell.diff
and add the following to your kernel config:
options HIRES_BELL

Please let me know if this resolves the "hum".

Best regards,

Nat


On Mon, 22 May 2017 21:10:00 Paul Goyette wrote:
> The following reply was made to PR kern/51784; it has been noted by GNATS.
> 
> From: Paul Goyette <paul%whooppee.com@localhost>
> To: gnats-bugs%NetBSD.org@localhost
> Cc:
> Subject: Re: kern/51784: "Synthesized" speaker hums
> Date: Mon, 22 May 2017 19:05:36 +0800 (+08)
> 
>  FWIW, this is still an issue with 7.99.72