Re: [LAU] hardware - Intel CPUs

On Wed, 16 Apr 2014, david wrote:

> On 04/16/2014 03:17 AM, Len Ovens wrote:
>> I was talking about through air. I can only play as fast as I can hear
>> and at thirty feet or so from the sound source, my instrument sounds
>> delayed from the rest of the band because I hear their sound that much
>> later and play my part that much later. I don't normally play at that
>> distance, but ten feet is pretty standard.
>
> You're a few orders of magnitude better than me! I don't think I'd notice
> that much difference.

I used to play and try to adjust sound while practicing, so I had 50 feet
or so of cable. By the time I got to the sound board it was getting hard
to play.

> I use headphone monitor.

I find monitoring with headphones when playing bass is hard. I use a small
amp tilted back about 10 feet ahead of me... so 13-14 feet to my ear I
guess. Bass needs some space to work. My amp just gives me enough for me
and the board can add whatever they want to the mains. I go a bit heavy on
the high end for my monitor and the mains can roll that off for house
sound.

> That's my understanding, too. Things like staying away from USB mice and
> keyboards, making sure the USB audio is the only device on that bus, yah?

On that irq... same for pci(e) really even prioritizing shared irqs, lone
irqs are still best.

>> However, it looks like I can still get lots of MB with PCI slots in
>> them. I will probaly do that. Hopefully with three PCI slots I can get
>> one that is irq clean.
>
> My desktop has 2 PCIe slots; the other 4 are PCI. It also has 4 USB ports +
> 2 more USB connector points on the mobo, 4 SATA connectors, an EIDE
> connector, a floppy connector, plus the built-in audio and video and
> Ethernet. I haven't checked to see what's sharing interrupts and what isn't.
> I wouldn't be surprised if there aren't a bunch of shared interrupts!

cat /proc/interrupts will tell you that quick enough. For some reason a
lot of MB share irq16 with 3 or 4 things... worse one of those tings is
often one of the PCI(e) slots. No need really as most modern MB have
access to 48 plus irqs. My old board has 24 but 2-7 are unused (for
hysterical reasons?) and 10 and 13 seem to be skipped too. I think 20 goes
to my internal audio which I have turned off (AC97) so it doesn't show.

I have noticed that on any of the MB I have checked or seen irq maps for
that the internal audio always has it's own irq and quite often it is the
highest one which in most systems these days has the most priority. I
found this out because I had the card I was using for midi in the higher
of the two slots and my audio below. I had trouble with xruns on the
audio, but when I put the audio on the higher irq I had no more trouble.

I know that in theory that shouldn't happen because there are two part to
the irq drivers, a stub to answer the IRQ and save enough info to work and
the other part that the os prioritizes and does all the work. So the os
should be able to prioritize by the module name. I just know what I have
found works best.

I have heard the words "in a modern system" too many times. I think any
system can do better audio if it is tuned/tweaked.

--
Len Ovens
www.ovenwerks.net
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