[pulseaudio-discuss] Pulse Audio 4.0 gets killed by 300 Hz tone...never recovers

[Robert Krakora]

The Speex sample rate converter has problems it appears and consumes and
inordinate amount of CPU upwards of 57% when converting from 44.1 to 48 and
it still sounds bad.  Even with the Audacity generated 300Hz tone at 44.1
the quality does not improve.  If I suspend PulseAudio 4.0 and play with
straight ALSA, all of the problematic wave files at 44.1 play beautifully
with little burden on the CPU.  I have tried the 'tsched=0' recommendation
on the udev module load line and still get the same poor quality.  I use
PulseAudio primarily for echo cancellation during video conferencing for
which it performs beautifully.  Is there a way to bypass the
mixing/resampling in PulseAudio and let ALSA perform these functions?


On Tue, Jun 25, 2013 at 12:03 AM, Robert Krakora <
rob.krakora at messagenetsystems.com> wrote:

> Hi Peter,
>
> If I convert all four files, which sent you, to 48K then they all play
> fine via PulseAudio 4.0 (no motor boating).  The frequency spectrum of the
> 300Hz tone at 44.1K looked a lot different from the 300Hz tone generated by
> Audacity at 44.1K.  I agree that the tone is not perfect.  However, the
> other three files also play poorly on PulseAudio 4.0, but play fine on ALSA
> 1.0.25.
>
> Best Regards,
>
> Rob
>
>
>
> On Mon, Jun 24, 2013 at 8:26 PM, Robert Krakora <
> rob.krakora at messagenetsystems.com> wrote:
>
>> Hi Peter,
>>
>> Thanks, I suspect the resampling as well.  I will take a look at the wave
>> file with audacity and generate a pure 300 Hz tone.  Thank you for your
>> time.
>>
>> Best Regards,
>>
>> Rob
>>
>>
>> On Mon, Jun 24, 2013 at 7:23 PM, Peter Meerwald <pmeerw at pmeerw.net>wrote:
>>
>>>
>>> > I just provided the files to you via YouSendIt.  You should be
>>> receiving an
>>> > e-mail with a link to them.  Thanks in advance for your help.
>>>
>>> the mysterious 300HZ.wav is not a pure 300Hz tone;
>>> it plays distorted (on ALSA and PA) because the signal is distorted
>>>
>>> when you look at it in Audacity (Analyze -> Plot Spectrum) you see plenty
>>> of frequency components besides 300Hz; you can generate a pure 300Hz tone
>>> using Generate -> Tone and compare
>>>
>>> I do not know why ALSA and PA sounds differently for you, it might be
>>> resampling
>>>
>>> regards, p.
>>>
>>> --
>>>
>>> Peter Meerwald
>>> +43-664-2444418 (mobile)
>>>
>>
>>
>>
>> --
>> Rob Krakora
>> MessageNet Systems
>> 101 East Carmel Dr. Suite 105
>> Carmel, IN 46032
>> (317)566-1677 Ext 212
>> (317)663-0808 Fax
>>
>
>
>
> --
> Rob Krakora
> MessageNet Systems
> 101 East Carmel Dr. Suite 105
> Carmel, IN 46032
> (317)566-1677 Ext 212
> (317)663-0808 Fax
>



-- 
Rob Krakora
MessageNet Systems
101 East Carmel Dr. Suite 105
Carmel, IN 46032
(317)566-1677 Ext 212
(317)663-0808 Fax
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