pbowne Posted August 22, 2014 Share Posted August 22, 2014 I have a home-built PC music server that has been wonderful to listen to. Just recently I got new SATA cables and used 3m AB5030 EMI/RFI to shield the cables and some of the chips on the motherboard. When I start listening to music it sounds fantastic, but after 30-60 seconds it starts exhibiting major distortion and, get this, the music drops a half to full step in pitch. I've never experienced a change in pitch in the digital domain before. For background, I am using the following: Intel Celeron G1620 cpu with Integrated HD Graphics (so I don't have to use a video card) MSI B75MA-E33 (Military Class III with solid caps) LGA 1155 MicroATX motherboard Patriot Viper 3 DDR3 1600mhz 4gb (1 stick - I can add another if I need to) Seasonic S12II SS-330GB 330w ATX 80 PLUS Certified PSU Kingston SSDNow 200 64gb 2.5" SATAIII solid-state drive 2 Hitachi hard drives with a lot of music (and room for more of it) one 3tb and one 2tb. An Anker Astro E4 13000mAh Portable Battery pack to power the SSD drive ASUS Xonar DS PCI soundcard with upgraded opamps Microsoft Server 2012 None of the equipment other than the SATA cables has changed. _______________ What could be the cause of the increasing distortion and change of pitch? Peter BTW. I really appreciate all the good articles and advice I've gleaned from this website. Link to comment
Foggie Posted August 23, 2014 Share Posted August 23, 2014 Have you tried installing the original SATA cables back in (assuming everything was working fine prior to the cable switch)? My rig Link to comment
PeterSt Posted August 23, 2014 Share Posted August 23, 2014 Peter, Something can't keep up, and this coincidentally expresses as skipping samples. With this latter I mean : this will change the pitch (skipping one of the other sample will make the pitch twice as low). If you really only changed the SATA cables (and that shielding) it is likely that something is bad and noise is implying "re-tries" which consume resources. That you only notice after a while is because at some stage the work to be done to correct is conflicting with the resources needed for audio playback itself. This is a bit hard to explain, but what happens is not strange. Lastly, whatever your shielding is supposed to do, notice that no EMI/RFI/etc. can be absorbed or something; so what can easily happen is that what you guide away from one place now collects in another (think high beam) and there things can't bear it. So removing that shielding can already solve the problem. Regards, Peter Lush^3-e Lush^2 Blaxius^2.5 Ethernet^3 HDMI^2 XLR^2 XXHighEnd (developer) Phasure NOS1 24/768 Async USB DAC (manufacturer) Phasure Mach III Audio PC with Linear PSU (manufacturer) Orelino & Orelo MKII Speakers (designer/supplier) Link to comment
mac_and_dac Posted August 23, 2014 Share Posted August 23, 2014 Just a punt - maybe an unlikely one - but could the change of pitch also theoretically be a result of the incorrect detection of sampling rate by the dac, as a result of some other issues? </ducks> Front End: Neet Airstream Digital Processing: Chord Hugo M-Scaler DAC: Chord Dave Amplification: Cyrus Mono x300 Signatures Speakers: Kudos Titan T88 Link to comment
PeterSt Posted August 23, 2014 Share Posted August 23, 2014 If you ask me ... During playback ? no. At the start of it theoretically yes, but the chance that some data (byte) is coming across in wrong fashion and then implies exactly this, is so unlikely that I better say "theoretically also no". This, while it is very easy to skip one of the other sample and perceive what happens (or one out of 10 etc. with a just 10% lower pitch). Notice that it is NOT easy to mimic such behavior with just wrong buffer settings as such; it is a behavior of what the CPU is held up with and priorities for it. Since this must be interrupt related (to let the lower pitch happen) it is also likely that it is about hardware errors hence re-tries. So, we can imagine that audio playback has priority over about all or otherwise we would never be able to play fine music, but once the music data itself can not be read in well fashion, what to do. Lush^3-e Lush^2 Blaxius^2.5 Ethernet^3 HDMI^2 XLR^2 XXHighEnd (developer) Phasure NOS1 24/768 Async USB DAC (manufacturer) Phasure Mach III Audio PC with Linear PSU (manufacturer) Orelino & Orelo MKII Speakers (designer/supplier) Link to comment
jriver Posted August 25, 2014 Share Posted August 25, 2014 Just a punt - maybe an unlikely one - but could the change of pitch also theoretically be a result of the incorrect detection of sampling rate by the dac, as a result of some other issues? </ducks> I agree that it's on the playback side if the pitch changes. It's not anything related to getting the data to the player. Either the player or the driver are having trouble. Jim Hillegass / JRiver Media Center / jriver.com Link to comment
pbowne Posted August 26, 2014 Author Share Posted August 26, 2014 Since I had used the original SATA cables to shield, I've ordered new plain SATA cables to substitute. I'll try them as soon as I get them. If that doesn't work then I'll have to go back and , bit by bit remove shielding from wherever I put it. Link to comment
pbowne Posted August 26, 2014 Author Share Posted August 26, 2014 Makes a lot of sense. I had been thinking along lines that EMI/RFI is absorbed/removed so I have to rethink the process. If the plain SATA cables don't change it back then I'll do a step-by-step removal of the EMI shielding until it works properly again. Link to comment
pbowne Posted August 26, 2014 Author Share Posted August 26, 2014 The player or drivers haven't changed (forgive me, but I've used MediaMonkey Gold as I like the way it's organized) so PeterSt's comments that EMI beaming causing overload in reading cycles in a chip somewhere seems to make the most sense. But I am willing to learn throughout the process of correcting this problem. Link to comment
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