Re: [LAU] Value of low-latency in audio?

Jonathan E. Brickman wrote:
>
>> Just wondering. Without an RT kernel here, my 2 laptops seem to run my
>> simple audio needs pretty well at 64msec latency. At least, it's never
>> bothered my playing along with computer-generated audio.
>>
>> I don't do any heavy-duty audio work here. Once I tried Jackrack, put
>> one effect in it (that worked) or one amplifer (that worked) but trying
>> to use both didn't. But I don't know if that had so much to do with
>> latency or lack of RT kernel as with a smallish amount of memory and an
>> underpowered processor driving the whole thing. Now that I''ve upgraded
>> the memory on both laptops, perhaps it would work? On musicbox, with
>> 512MB, using a single good quality (larger) soundfont was enough to
>> cause problems. With 768MB in it, it works without problems.
>>
>> I see people on the list running much lower latencies than 64msec, and
>> seemingly trying to get even lower ...
>>
>> So, just wondering.
>>
> Depends entirely on specifically what you're trying to do. I'm using my
> setup as a live-gig MIDI module, in the sense that when I play a note on
> my keyboard, it sends noteon/noteoff via MIDI to the box, which either
> (a) puts out that note as close to zero-latency as possible or (b)
> delays everything, which hurts live cohesion in many ways, not the least
> being my fellow band-members taking cues from the positions my fingers
> are in.

That's sort of what musicbox is headed for.

> It's true that RAM and CPU are both needed if you're going to use your
> laptop for effects. A good sound system can ease the CPU needs some,
> but not much in the effects zone. Apart from MIDI event processing,
> soundfonts are actually perhaps the least resource-intensive
> music-generation task in my current experience, as long as your sound
> system is reasonably tweaked, except some simple sound synthesis tasks
> in well-written code, e.g., some organ-only simulators. Sophisticated
> sound synthesis will eat your CPU alive (that's why I bought this AMD
> X4), as will anything but the simplest effects setup.
>
> Which brings me to a 'hmmm'. CPU. GPU? :-) Not yet, but we can pray
> for it :-)

CPU in musicbox is a 2.8GHz Celeron processor. Not the Celeron M, the
non-M version.

The "GPU" is old Intel 8xx series junk, and probably the source of about
half of the xrum problems ... I tried a music distro on it that used
KDE3 with Compiz, and having any of the video effects turn on would peg
the CPU and bring sound processing to a silent halt.

-- 
David
gnome@email-addr-hidden
authenticity, honesty, community
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