[LAU] Crackles in audio - how to troubleshoot ? Tim's TEST RESULTS:

[Len Ovens]

On Fri, 26 Aug 2016, jonetsu at teksavvy.com wrote:

> On Thu, 25 Aug 2016 18:19:17 -0400
> termtech <termtech at rogers.com> wrote:
>
> Replacing the capacitors could be something to do.  Are they easy to
> get ?  How many of these are on the card ?
>
> OTOH, I was at the music store recently and upon mentioning 1010LT the
> remarks went on about age and who is older.  Maybe it could be time to
> upgrade to a newer card.  Maybe.  I have no idea on what's on the
> market that plays very well for Linux.  I'll start another thread.

All reasonably priced audio interfaces with at least 8 ports are USB2.0. 
Yes they work... But none of them are a match for the 1010 in stability or 
latency. The other side of the arguement is that PCI itself is dead. Even 
on the MB that still have them (I bought a new MB with three of them just 
so I could choose the best one for my ice1712) they are possibly bridged 
via PCIe.

The general thought in the Computer Audio community is that USB is what we 
have to "put up with". Very few people have spent the time with USB that 
in the past was spent on PCI audio, because it is just expected to have 
poor(er) performance. Latency changes depending on what time it is when 
the port is opened... etc. At least one person has found that the USB host 
chipset makes a rather large difference in performance... The ones on 
almost any motherboard will use Intel technology which just like some of 
their USB 3 chips are not very good for Audio. Buying the right PCIe to 
USB card can improve things a great deal. It can have it's own IRQ as well 
as a good chipset.

(see 
http://crimeandtheforcesofevil.com/blog/2016/07/25/so-hey-usb-chipsets-totally-matter/ 
)

Another thought that hits me about this is that the 1010 (not the LT) was 
not cheap when it first came out. Allowing for inflation perhaps some of 
the Audio Science (and other) PCIe cards are not so far off.

There are also some USB3 kinds of things starting to show up. Like:
https://www.blackmagicdesign.com/ca/products/ultrastudiousb3
While it shows as a video interface... it does have at least 8 Audio i/o 
as well. The problem is that while the price is not bad... there are only 
4 analog connector sets and they are line level (+4dB). There are some 
extra AES but at least some of those are shared with the analog lines. The 
real audio expansion would be with SDI or HDMI inputs and outputs which 
are 8 audio channels each. Costwise $900 plus $300 for one of these:
https://www.bhphotovideo.com/bnh/controller/home?O=&sku=1082829&gclid=Cj0KEQjw0f-9BRCF9-D60_n4rKcBEiQAnXW4-4CSe2dKMXNOawl5XGYp9Du0MNCUe5wi7j-LLlhrKoMaAt928P8HAQ&Q=&is=REG&A=details
to get some extra inputs. Add the cost of preamps to that... (though the 
delta 1010, 66 and 44 would have the same requirement so you may already 
have preamps or a mixer)

I would suggest that this would be cheaper:
http://www.audioscience.com/internet/products/sound_cards/asi574x.htm
While they call it 4 channel they are 4 strereo channels for 8 audio lines 
all together. There is also the:
http://www.audioscience.com/internet/products/sound_cards/asi578x.htm for 
16 audio i/o.
These do both have alsa kernel modules and there is linux commandline 
tools for setting the internal mixer. If you can find 8 pcie slots on your 
motherboard... you can keep adding these till you fill your computer and 
they will all be sample synced. Again these are line level devices. Quite 
honestly, these are the devices I will be looking at to replace my delta66 
when I am forced away from PCI in a future motherboard choice. (when I can 
no longer find MB with PCI slots) I have not seen any USB AIs I would 
consider using. Yes the USB boxs have preamps, but the quality is 
questionable anyway. They are expandable but it seems USB chipsets that 
work with them are few or they stop working with some kernel releases. USB 
is not really designed for low latency audio. It has always been a 
consumer grade, cheap and easy solution for both the manufacture and the 
user.

In the end, good audio costs. If you are doing live work, latency matters. 
For recording not so much. If you are currently using monitoring that 
goes through the computer, buy a mixer! At least get an AI that has an 
internal mixer for monitoring. In my opinion, no one should be recording 
with through the computer monitoring.

Anyway, I am sure lots of other people will have comments to balance out 
my biased thoughts.


--
Len Ovens
www.ovenwerks.net