=== jta_ is now known as jta
=== Lump|AFK is now known as LumpOfCoal
holsteinzequence: im not an electornics expert22:00
holsteinso we dont have to talke about taht in the main channel22:00
holsteinzequence: i dont care22:00
holsteinim just saying, i ge more noise at lower latency22:00
holsteinwhy? im assuming something is doing more at lower latency22:00
holsteinis it power?22:01
holsteini dont know/care22:01
holsteinhypothesise away, but i assue you im not tyring to be "correct"22:01
holsteinim just stating what i have seen 22:01
zequenceI'm not making any claims that are "hypothetical"22:01
zequenceJust narrowing down what could and what could not be the cause22:02
zequenceI'm only interested in solving the problem22:02
zequenceI've sometimes experienced that a screen can cause noise to audio devices. The whiter the color, the more noise22:04
zequenceAnd it has happened that a hard drives activity has leaked into the audio signal as well22:04
zequenceIn both cases I would think it's some sort of ground problem22:05
holsteini would hypothesise a power issue there as well22:05
zequenceIf the CPU activity is audible, then it kind of sounds like the same thing. I was jusr surprised that low latency would be that audible, as it's not really that much more CPU intensive. If it is a ground problem in this case, it would make sense that anything CPU intensive, at any latency would give noise22:07
zequenceJust that there might be more noise at lower latencies when the PC is idle22:07
holsteini dont think its cpu activity22:08
holsteinits a constant noise22:08
holsteinyou start jack at that latency, and its pretty steady22:08
holsteini high pitch whine22:08
holsteinits odd22:08
holsteini solved it much the same way though.. by looking into grounding22:09
len-1304holstein, The PS for the FW unit may be a switcher.22:09
zequenceholstein: You said that the noise increased in volume at lower latencies. Does the pitch change too?22:09
holsteinzequence: i dont remeber that.. but i dont think so22:10
holsteini think it ws the same pitch and louder22:10
len-1304Sounds like the power supply22:11
len-1304 Small switching power supplies have gotten cheaper... I see them even in wall warts22:11
zequenceIt's just that I don't see how the latency would affect the FW power supply22:12
holsteinif it causes the device to pull more power22:12
len-1304If it is an old unit, I would think the caps are drying out.22:12
zequenceBut, how would it do that? It's a constant stream of data, no matter which latency22:12
len-1304The FW unit fills a buffer and sends it every so often, low latency means the cpu in the FW unit has to deal with that part of things more often22:13
zequencelen-1304: Isn't that done in the CPU?22:14
zequencethe buffering, I mean22:14
holsteinzequence: i think you are assuming a constant stream of data.. maybe its not constant?22:15
holsteinin not sure22:15
zequenceIt is a constant stream, but it's also buffered22:15
zequencelower latencies means smaller buffer sizes22:16
zequenceI'm just assuming the buffering is done in the CPU, and not in the audio device.22:17
=== LumpOfCoal is now known as Lump|AFK
zequenceAFAIK, an audio device sends and receives one sample at a time, following the clock22:24
holsteini wish i knew more about it22:24
zequenceIf you increase samplerate, the rate at which samples are sent/received increases22:25
len-1304zequence, (just had lunch) the FW unit also buffers (as does the ice1712) and sends a bufferfull of data at a time. The driver tells the IF how big the buffers are that it wants.22:44
len-1304That is why there is a lower limit to buffer size for any IF.22:44
zequencelen-1304: How about a higher limit?22:46
zequenceWhile jack has a limit of 4096, OSS can go higher22:46
zequenceBut perhaps the sound server makes up for it22:47
len-1304That would be a jack limit then.22:47
zequenceI wouldn't expect audio devices to be limitless anyway22:47
len-1304The bigger the buffer used the more shared memory must be set aside22:47
len-1304But I have three audio interfaces, the lower limit on each is different (-p128, -p64, and -p32) Jack will not even start if I try to use less... because jack tells alsa to ask the device to set a smaller buffer size than it can and the device refuses (sends an error back)22:49

Generated by irclog2html.py 2.7 by Marius Gedminas - find it at mg.pov.lt!