I think rumour-control needs a reality check here - not under discussion or even consideration AFAIK
Ok and out of interest, you are only the second person I have seen using ‘AFAIK.’ The first was my sw guru colleague.
The problem with USB is that it sometimes struggles to keep up wth the exacting demands of recording digital audio, particularly on slower older processors - recording the audio is absolutely real-time any interrupt and audio gets lost - and in extreme cases the USB device appears to go AWOL and just generates “noise” until the whole system is reset.
Interestingly, I seem to recall Sombunya only had to stop the recording (I only have to pause) and re-start to remove the problem and not reset his system.
My sw guru has been reading this discussion and, completely without provocation, wrote the following:-
"In case of a HW bit error rate of 10^-9 for a 192kbps@32bit stereo (extreme case recording) you would get an error for every 81sec (as total audio bitrate is only like 12Mbps and not 480Mbps) and not every 2nd second as you mentioned in the thread, but it’s just a minor detail => What you see is certainly not USB HW bit errors I’m 99% sure.
In case SW can’t follow the speed, I would as well find it very strange. After all 12Mbps is nothing on a newer PC. (like 2.5% USB utilization). I recognize the hard real time requirement and being coded wrong it could be a problem, but I find it strange to believe. A 15fps VGA Web camera would need 15640480*8 = 36Mbps (just as an example)…
Even in case of storing data to USB hard drive connected to same USB Host controller, it would still only yield like 5% total USB but utilization with 2.5% being able to get moved to when it would fit in time… As you mention as well storage to Harddrive is guaranteed to be 100% fail safe (as it’s bulk). Only the potential isochronous input won’t be…
The above has been copied verbatim. I think on this point we ought to agree to differ. There are a number of persons that will agree with your statement that USB causes problems and FireWire does not even though they are both isochronous and, give or take, operating at similar speeds. Having designed USB interfaces and been responsible for stress testing to prove hw design and PCB layout, which does have consequences at 0.5GB/sec (the edges are much higher frequency than 0.5GHz), it will be extremely hard to convince me. My sw guru was my cohort when we were working at TI in Denmark, hence the understanding between us. I do not dispute that you have seen problems with USB interfaces but I do not believe for one moment Sombunya’s problem is the data rate on the USB link. As I said, I think we ought to let this one die a death, especially as I am not using USB. If you wish, I will allow you the final word I can’t be any fairer than that can I 
and in effect you almost seem to be agreeing with me with and I quote:-
I personally have used USB devices with Audacity from 1.2 4 to current to transcribe hundreds of LPs and tapes, initially with a USB TT which was rubbish (electronics good but platter lousy with too much wow & flutter) and latterly with an ART preamp and an Edirol UA-1EX USB soundcard with my old Technics TT and SME 3009. These have produced excellent recordings throghout with no USB or Audacity problems (and I listen on high-end kit QUAD electrostatics ESL-57’s and QUAD pre and power amps).
You have ripped hundreds of albums using a USB connection and I assume, though you never stated, did not have any problems. Surely if USB is such a big problem you would have had many many problems with rips going wrong or is it you did have problems and have not reported these problems in this post?
You also state:-
One thing I have noticed from several years of reading and working on this forum is that folk who deploy high-end-kit running at extreme settings seem to be the folk that often post issues - those who stick to industry “standard” bitrates etc. for CD/DVD production seem to suffer less of these problems.
and I have to wonder why as well; I believe I now know the root cause of the problem or at least a strong pointer to the problem in my system but more on that later…
@Gale:
VinylStudio ( > http://www.alpinesoft.co.uk/ > ) apparently records up to 32-bit 192 kbps. What quality do you use in that program?
I am making all my rips at 24/96 and for testing purposes I use 24/192. I have run Vinyl Studio on my, very slow, XP system capturing audio at 24/192 until the 4GB file limit is reached. I have run three successive tests and there was no problem. I can run more tests, and also run the same tests on my Win7, if you think this can be of any benefit. The 24/192 is only set in sw because, although my ADC box will do 24/192, I have not succeeded in getting the S/PDIF interface on my M-Audio card to lock to the higher sampling frequency. The M-Audio card seems to divide any sample rate above 96kHz by 2. I could use the 24/192 card to generate samples at 24/192 if you think this could make a difference though I do not see how running the sw at twice the sample rate of the ADC box could be a problem.
I know you (Dennis) are not using USB but I guess if you are not present during any recording you could try not using Software Playthrough.
I am always present during recording or at least the recording process is always within earshot so I do not wish to turn off play-through especially as I would then have to listen to everything ripped later. I have about 900 albums to rip in 90 days. This is quite a task ahead so I have little time for repeat playing or ripping.
To me the most likely reason is the very high sample rates combined with some event when the computer has to do some short intensive task. Possibly this is more likely to happen if you are using playthrough. Possibly if Vinyl Studio does not distort, it may be that it is a lighter footprint application or doesn’t write blocks every few seconds. 1.2.6 may be sufficiently “lighter” to record properly under circumstances where you are at the point of tipping over the edge into distortion to the high sample rates/bit depth.
I agree, it seems as if something is overloaded but the rate is not so high for hardware or software so I am not sure I can agree with you. There is enough going on here to leave me very puzzled.
I don’t recall, but is there anywhere else in your chain where you are using a different sample rate and bit depth than you are setting in Audacity?
No, when I am recording everything is set identically. I only use a higher sample rate for testing and never a lower rate. My tests have shown virtually identical 2:1 ratios when I halve the sample rate.
Are you choosing Windows Direct Sound as Host in Audacity Device Toolbar? DirectSound should have much lower latency than MME on XP.
I have been using the default which, I believe is MME.
To me the most likely reason is the very high sample rates combined with some event when the computer has to do some short intensive task. Possibly this is more likely to happen if you are using playthrough. Possibly if Vinyl Studio does not distort, it may be that it is a lighter footprint application or doesn’t write blocks every few seconds. 1.2.6 may be sufficiently “lighter” to record properly under circumstances where you are at the point of tipping over the edge into distortion to the high sample rates/bit depth.
Agreed, it seems like a work loading and task conflict. In the following paragraphs I would hope you can see why one has to keep an open mind when trying to diagnose problems.
Ok, now to the crux of the problem, this is part of the email I sent today to my sw guru:-
I have changed to Vinyl Studio and no problems, that is, until a couple of hours ago i,e, the rip of my 5th album today, prior to this I had ripped 24 albums with Vinyl Studio. On the 5th album there was severe distortion at the start of the recording, press pause, and start and everything is okay. Why one asks. Hopefully the reason is simple. Last night I changed my Audio card I use for the S/PDIF interface back to the 24/192, I am using the 24/96 card for testing on my XP system. I suspect the S/PDIF interface, RAM or some other hw, on the 24/192 card is not behaving properly. I not only changed to Vinyl Studio when I had the distortion, I also changed my hw set-up from the S/PDIF interface using the 24/192 M-Audio card to one using the 24/96 card. I know I know, one change at a time. So now I am back to ripping using the 24/96 card as the S/PDIF interface. However, our discussion regarding the USB distortion, which is were we came in, is still valid. It just goes to show you have to keep an open mind on these issues. I was convinced this was a sw issue but now it seems, almost certain, there is a problem with the S/PDIF interface/hardware circuitry on the 2nd audio card. I also had other recording issues today whereby the record function did not work i.e. Vinyl Studio was not communicating correctly with the sound card drivers and I had to re-boot my Win7 system + the S/PDIF interface lost sync on two occasions after stopping a rip which required the M-Audio interface and Vinyl Studio to be restarted. (The previous sentence has been added for completeness.) I have not seen these types of error before in all of the rips. Problems problems and no test gear to be certain as to the root cause.
I was so surprised at the distortion I did not think carefully and I failed to record the sample, actually I overwrote the sample. In Vinyl Studio you have to give the file name at the start of the rip. I do not know if the distortion has occurred at capture, replay or even in the ADC or DAC boxes.
I do not believe Audacity could have random data capture buffer errors so unfortunately that only leaves an error on my part. Put into words of one symbol, I must have missed the distortion when I was monitoring the album rip. How, why, I could have missed this I have no idea. I still have doubts that I could have missed distortion that is so bad. Maybe the monitor function was switched off but I do not think this was the case. Suffice to say I cannot give any concrete root cause but I no longer believe Audacity is at fault unless of course there is a common function or library that both Audacity and Vinyl Studio are using. I still have a long way to go with my rip so there may be more progress…
There are only two good things that may have come out of this discussion:-
i) It is most important to keep an open mind
ii) At the present time-slice my noise seems to be caused by a faulty audio sound card; it will be interesting if I have another occurrence of distortion. Now that would really put the cat amongst the pigeons, as we say.
I will have to make the appropriate connecting cables and then I will start to rip using the suspect, 24/192, M-Audio card do digitise the audio thereby removing the ADC box and S/PDIF input interface from the data collection path. This is not a 5 minute task as I do not have the appropriate connectors to make the required cables so please be patient and of course, I may have to rip a large number of albums to have a high confidence level.
Let me ask a question, how can the identical symptoms that both Sombunya and I have experienced be caused by USB in his case and a hardware sound card in my case? The identical symptoms was described by Sombunya as if the LP was a bad pressing, static, loose connections etc. and sibilance by myself. These errors were resolved by breaking the audio capture process. Using both Audacity and Vinyl Studio, my error was resolved by pausing, maybe Sombunya stopped and restarted his recording session. Something still does not seem correct here but what, I do not know.
If I have any news I shall update this post.
