View Full Version : Keith's new streamer
I've been using an ancient HP tower PC to stream music from my linux server to my Caiman DAC for a while. This PC was getting more unreliable (often taking a couple of goes to boot) and was still a little bit too noisy, even after me replacing the CPU cooler with a quieter one, new case fan and mounting the hard drive on sorbothane bosses. Also, I want to re-arrange the system in the room shortly which will mean hiding the tower inside a wooden chest won't be possible and I don't want an ugly PC on display.
Also, I've been using XBMC Media Centre - which is a bit over the top as a pure music solution - requiring a fast(ish) gpu etc., even though most of the time I was using the XBMC Andriod remote app rather than having the PC connected to my telly.
So I decided a new streamer was needed. My requirements were: silent - no moving parts, low power consumption, external power supply (so I can upgrade to a linear PSU in due course), headless - use an Andriod client app, software with 'audiophile' pretensions and (most important) CHEAP :)
I decided to build a silent PC based on a mini-ITX form-factor motherboard, Intel Atom processor, 1GB DDR3 RAM, fanless case and a 16GB SSD that I was given for free.
http://www.simister.com/public/streamer.jpg
(CD case shown for scale)
The PC runs Voyage MPD - a stripped-down linux distro optimised for music playing. The whole OS is loaded into memory, so there is no disc access after boot up. I'm running MPDroid Andriod client - currently on my phone - but have ordered a cheap 9" Android tablet for more convenience.
http://www.simister.com/public/mpdroid1.jpg http://www.simister.com/public/mpdroid2.jpg
http://www.simister.com/public/mpdroid3.jpg http://www.simister.com/public/mpdroid4.jpg
Cover art can be displayed, but it requires Android 4.0 or greater (which my phone doesn't have, but my tablet will)
The processor is barely ticking over when playing music, so I will investigate underclocking to further reduce power consumption.
http://www.simister.com/public/top.jpg
I'm very pleased with it so far. It sounds great (better than my old XBMC Media Centre), looks neat and tidy and is very simple to use (push power button and wait 15 seconds, play music. When finished, press power button to switch off).
Future upgrades will be galvanic isolation for the USB, linear power supply to replace the current 12v switcher and S/PDIF output via isolated BNC socket for hi-rez formats.
Total cost was:
£40 for a second-hand Intel D525 motherboard with dual-core Atom processor and 1GB DDR3 RAM
£40 for the case (ebay)
£15 for 12v 10A power brick (ebay)
99p for 15cm SATA cable (ebay)
I already had the Kingston 16GB SSD (free).
That looks great Keith, I like the case, nice and compact.
Voyage MPD has been on my list of things to try one day, ever since John mentioned it, I really like the tiny ARM board you can buy for it. I would be interested to hear how you get on with Covert Art with the tablet, as that's something I like to have. Your requirements are the same as mine, headless, totally silent and low power - what board did you go for?
That has to be one of the lowest cost streamer's I have seen too, hats off to you fella :)
(I'm sure Martin will be along to mention your CD illustration ;))
Thanks Tim. The board is the Intel D525MW - it has a soldered-down Atom dual-core (1.8GHz) processor and fixed heat sink. It's probably over the top, but I could lay my hands on one cheaply second hand (with the RAM thrown in too).
The ALIX boards are a good choice for Voyage MPD - you can buy a ready-built solution based on one of these with Voyage MPD pre-installed on a Compact Flash card for about $140.
http://store.voyage.hk/KMPD2h.php?id=72
Thanks Keith, I have an Intel DN2800MT waiting to go into my server when I can find the time and that ALIX board you have linked to is the one I was referring too - I think that's what John uses?
I am totally sold on file streaming now, not for everyone I know but being able to flick through a collection approaching 3,000 on a tablet and playing music with just a screen touch is fantastic and I love it, especially as it sounds superb too.
I still cannot get over how cheaply you have done it, that deserves some kind of award :D
http://i173.photobucket.com/albums/w63/greatgig/Trophy.png
nice one keith.
I must think about doing something like this.
Ha! Just made a few changes to the config whilst it was playing music and shut it down without stopping the music playing. When I powered it back up, it immediately started playing from exactly where it had left off :lol:
Don't know why I'm impressed, but I just wasn't expecting that to happen :cool:
That's a very neat project Keith. It's "cheapness" helped by picking up a s/hand m/board and having a spare SSD. With no picoPSU in the mix I assume your m/board has a 12V DC jack, which is not that common.
You mentioned a possible future upgrade of a linear PSU but if it has a single rail input will you not still have to rely on the m/boards regulators for +/-5V and 3.3v? Does this defeat the object? I know little about electronics, but wonder if the typical voltage regulation on m/boards can reject PSU noise, or does it simply add to it and what are the relative magnitudes of supply and on/board regulation "noise". I still wonder if such an upgrade is worth it.
You said: "the whole OS is loaded into memory" , I know about the "toram" boot option that can used with Linux LiveCD/DVD/USB stick, but wondered how your are doing this? MPD will exist in memory too. Have I missed something obvious?
Thanks Chris. The case has a built in dc-dc power supply feeding the mobo via the usual 20+4 and 4 pin power connectors.
Regarding the os running from ram, that's how Voyage works - everything is in ram. If you edit (say) /etc/fstab what you are actually editing is the copy of that file in ram. The changes get automatically synched back to the ssd on shutdown.
Nice.
There must be cut down versions of Linux for all sorts of applications, like music servers, Digital Audio Workstations, even manufacturing process control and all out there for free.
That's a very neat project Keith. It's "cheapness" helped by picking up a s/hand m/board and having a spare SSD. With no picoPSU in the mix I assume your m/board has a 12V DC jack, which is not that common.
I would have thought you could do this on lesser hardward too, stuff that's being recycled. Certainly dual-core processing is common to find thrown out and constitute my last two finds (three if you also count the Dell server with 2 x Xeons, but a bit noisy to say the least).
i.e. the only thing you need pay for IMO is reliable storage. The rest is down to fitting it in aesthetically and making sure it runs silently.
I wonder what those tvs with DVD players in the side have running in them. Probably Atom based SBCs (Single Board Computer)..
Thanks Chris. The case has a built in dc-dc power supply feeding the mobo via the usual 20+4 and 4 pin power connectors.
Regarding the os running from ram, that's how Voyage works - everything is in ram. If you edit (say) /etc/fstab what you are actually editing is the copy of that file in ram. The changes get automatically synched back to the ssd on shutdown.
Certainly the last time I looked VoyageMPD Linux mounts read-only, which is not quite the same thing as "the whole OS loads into memory". Have you for instance run IOTOP to monitor disk access after booting? I'm not picking holes here, I'm just genuinely curious.
I would have thought you could do this on lesser hardward too, stuff that's being recycled. Certainly dual-core processing is common to find thrown out and constitute my last two finds (three if you also count the Dell server with 2 x Xeons, but a bit noisy to say the least).
i.e. the only thing you need pay for IMO is reliable storage. The rest is down to fitting it in aesthetically and making sure it runs silently.
I wonder what those tvs with DVD players in the side have running in them. Probably Atom based SBCs (Single Board Computer)..
There's no doubt that Linux can re-vitalise older hardware, and recycling should not be discounted. But it's debatable if it's a greener solution, especially when older hardware is not necessarily very energy efficient.
The trick here is to work out the minimum specification required to support the audio SQ you are looking for. Linux, and the popular MPD software, has been successfully run on low powered devices like routers, plug computers and basic NAS boxes.
Certainly the last time I looked VoyageMPD Linux mounts read-only, which is not quite the same thing as "the whole OS loads into memory". Have you for instance run IOTOP to monitor disk access after booting? I'm not picking holes here, I'm just genuinely curious.
Hi Chris - no worries; pick away :ner:
I've not run iotop as to install it plus the raft of dependancies (python etc) needed isn't something I really want to do. I'm pretty sure I've read somewhere that Voyage works as I've described. Not scientific I know, but the hdd led never flashes other than during bootup and shutdown. I'll post any referrences should I come across them.
There's no doubt that Linux can re-vitalise older hardware, and recycling should not be discounted. But it's debatable if it's a greener solution, especially when older hardware is not necessarily very energy efficient.
The trick here is to work out the minimum specification required to support the audio SQ you are looking for. Linux, and the popular MPD software, has been successfully run on low powered devices like routers, plug computers and basic NAS boxes.
Hadn't realised that energy consuption was part of the equation.
If it is, you must realise that pre-heating your oven for 15 minutes longer than necessary will have wasted the equivalent of keeping the server on for probably a whole day in full power consuption mode, let alone the power saved from the difference in consuption between older tech and newer tech.
In the world of energy saving, the matter of magitude is often lost on people, with people saving 10 Watts here and there concisously (like turning the TV off standby) whilst ignorantly wasting magintudes of 10 or 100 more via re-heating food, putting too much water in the kettle, leaving ovens on, even to choices made in what food you eat and the energy consuption of eating one thing over another, like a cooked muffin v some locally grown fruit, blah blah.
All much more than saving 10Watts on the difference between tech. But it's too much of a head err, feck to keep everything in check, so just concentrate on the major things like anything that is used for heating or cooling and re-using 'wasted' energy for other purposes like using a big Class A amp during the winter so that the central heating doesn't have to work so hard.
Then on top, you must include the cost of energy of producing the new hardware and environmental impact of destroying/recycling the old hardware.
Then again you can just run the thing off a solar charged 13.8V lead acid cell into the DC-DC internal converter. Maplin do a large solar, leisure battery charger ..
The trick here is to work out the minimum specification required to support the audio SQ you are looking for.
In my mind, an old beige G3 mac should be able to handle it all ok as that was the standard for recording multi channel audio back in the day when things moved to native processing rather than external DSP in the home studio world.
The problem is not with the audio but the interface and graphics etc. Those should be shared with the tablet used and the server only acting as a kind of database plus outputing low capacity data stream to s/pdif.
Hell, a really old iPod can handle that even. It is only the implementation that stops it being the sonic delight that people want.
Nat,
I don't disagree with your analysis. I suppose I was wondering just how old is this old computer hardware. And yes, my Quad 306 helps keep me warm in winter.
Could even an old Via based Mini-ITX do the job? Single Core around 800MHz - I don't see why not seeing as a friend had built a 12 DAW successfully about 10 years ago that could run plug-ins smoothly enough too, whilst still maintaining smooth running of Cubase. Just an old Shuttle PC (I found one of them too with Ubuntu on it. Is just a little noisy).
Hi Chris - no worries; pick away :ner:
I've not run iotop as to install it plus the raft of dependancies (python etc) needed isn't something I really want to do. I'm pretty sure I've read somewhere that Voyage works as I've described. Not scientific I know, but the hdd led never flashes other than during bootup and shutdown. I'll post any referrences should I come across them.
Keith,
And you wont want to disconnect your SSD after boot either :) Does df -h show if VoyageMPD is using any kind of RAMDISK? It's a while since I've used it either in a VM or installed on a spare partition on my PC.
One audio test I tried was to remaster a stripped down Lubuntu in a VM with MPD and ncpmcpp set up to use some local audio files and with no graphical DE. Copied the iso and burn it on the host. Disconnected my hard drives and booted the LiveCD with the "toram" option and ejected the CD after system boot. Thus no doubt that OS and MPD and audio files where all in memory. The perfect memory player.
Did it sound any better than a more standard config? Not really :doh:. On better kit and with different ears, who knows?
Could even an old Via based Mini-ITX do the job? Single Core around 800MHz - I don't see why not seeing as a friend had built a 12 DAW successfully about 10 years ago that could run plug-ins smoothly enough too, whilst still maintaining smooth running of Cubase. Just an old Shuttle PC (I found one of them too with Ubuntu on it. Is just a little noisy).
Quite possibly, I don't know that much about VIA kit. There seems to be a ready supply of s/hand Eden family 800Mhz m/boards on Ebay. A single core 800Mhz CPU (with real floating point) should have a enough grunt for decoding and playback. You'd have to run the numbers on what must be a 10/100Mb NIC to check it's not a bottleneck for your intended use, and there's no SATA. I don't see older memory standards as much of a drawback, assuming you have or can pick up old RAM modules cheaply. Last thing I can think of is what ATX standard/pin config is used on these older m/boards.
As fas as overall hardware compatibilty with Linux the Debian HCL list is a pretty good guide: http://kmuto.jp/debian/hcl/VIA
Where's my old Duron and KT133? That bugger ran hot enough to fry eggs and was noisy as hell.
Keith,
And you wont want to disconnect your SSD after boot either :) Does df -h show if VoyageMPD is using any kind of RAMDISK? It's a while since I've used it either in a VM or installed on a spare partition on my PC...
Hmm. less sure now
http://www.simister.com/public/millhouse_filesystems.jpg
All the tmpfs mounts are ramdisc.
Anyway - it sounds good :)
Keith,
I don't think the whole OS being in memory really matters. As I'd expect, it sounds great, and your happy. Job done.
I'd expect, it sounds great, and your happy. Job done.
:D absolutely, but 'audiophiles' do seem to like picking over the bones somewhat ;)
Tim,
All is fair in love and war and the purist of audio nirvana.
It's a great combo you have in your main system. Can't we tempt you to make a cf between Linux and Windows on your streamer? Assuming the BIOS allows for booting from a USB stick, I'd would have thought VoyageMPD could be installed on and run from a pendrive.
It is something I have been intending to do for sometime now Chris, but I never seem to find the time. Thing is I can't bring myself to stop listening to music when I have spare time at home, as I spend my days working with computers so want to relax at home. I hope to retire soon and will throw myself at it a lot more then, especially Linux, I want to try and build the leanest, most energy efficient and obviously best sounding server I can, as I hope to sell them to top up my pension.
I'm due to update my current server imminently, so I'll have lots of spare components to tinker with, VoyageMPD is top of my list (I knew John (Welder) would get me in the end)
It will be similar in design principle to the Bryston with an on-board bespoke linear PSU and hopefully an app in the same league as Squeeze Commander to control it, which I think is very good ;)
It is something I have been intending to do for sometime now Chris, but I never seem to find the time. Thing is I can't bring myself to stop listening to music when I have spare time at home, as I spend my days working with computers so want to relax at home. I hope to retire soon and will throw myself at it a lot more then, especially Linux, I want to try and build the leanest, most energy efficient and obviously best sounding server I can, as I hope to sell them to top up my pension.
Good luck with the project ... Some of this a moving target, I wonder what ValleyView/Haswell will throw up?
I'm due to update my current server imminently, so I'll have lots of spare components to tinker with, VoyageMPD is top of my list (I knew John (Welder) would get me in the end)
I've exchanged a fair number of posts with John (Welder) re: Linux. It will always be my OS of choice, but I acknowledge Linux users are minority. I'd be very tempted to use the Intel DN2800MT but curse the day that Intel decided to base the GPU core on PowerVR SGX 545 which is poorly supported in Linux.
It will be similar in design principle to the Bryston with an on-board bespoke linear PSU and hopefully an app in the same league as Squeeze Commander to control it, which I think is very good ;)
I'm no electronics/audio engineer so it's hard to know just how crucial the PSU is to the quality of the Bryston player. The cynic might say they simply took the ALIX + VoyageMPD idea and turned into a high-end boutique device.
The cynic might say they simply took the ALIX + VoyageMPD idea and turned into a high-end boutique device.
:lol: that's exactly what they did, IMHO of course. But same as anything . . . they did it, did a good job, made some money out of it and made a lot of people happy in the process - they are a company after all, trying to make a profit whilst providing jobs and keeping their products in-line with current trends and it is a very good player, with I think a 5 year warranty.
Not many people in all honesty would ever think to build their own and its not until you pull this stuff apart, that you realise what its made off. Even when you do, there's still not that many people who tackle it, even with help.
Keith,
I'm hoping you're still monitoring this thread as I have a couple more questions.
1. You said your m/board is an Intel D525MW used with an external 120W power brick. The specs say this m/board has an ATX12V power header. So should there have been a picoPSU, or equivalent, on your parts list, or is it possible it's actually a different m/board?
2. Do you have the means to measure your streamer's power consumption?
3. Assuming frequency scaling (Intel Speedstep) is active on your system, what does the "cpufreq-info" command return when you're playing music?
4. Does the BIOS allow you to turn one core off? If so, can your system run just as well on a single core?
5. I wasn't clear, but are your audio files stored on a NAS?
6. Have you loaded lm-sensors on your streamer and monitored the operating temps, or at least checked them in the BIOS?
FYI, when using the "top", hitting "1" will show the load for each of your two CPU cores as opposed to a single aggregate line. An alternative program to try is "htop".
1. You said your m/board is an Intel D525MW used with an external 120W power brick. The specs say this m/board has an ATX12V power header. So should there have been a picoPSU, or equivalent, on your parts list, or is it possible it's actually a different m/board?
I'm using a dc-dc psu (ie. a picoPSU equivalent) that came with the case
2. Do you have the means to measure your streamer's power consumption?
No, not really. I guess it's around 35 watts or so.
3. Assuming frequency scaling (Intel Speedstep) is active on your system, what does the "cpufreq-info" command return when you're playing music?
I'd need to look more into this as cpufreq-info reports "no or unknown driver" for each core.
4. Does the BIOS allow you to turn one core off? If so, can your system run just as well on a single core?
I've not found an option to do that. Will look again next time I connect a keyboard and monitor
5. I wasn't clear, but are your audio files stored on a NAS?
Yes - actually on a linux box that I use as a fileserver, LAMP server etc. Audio files are accessed by a NFS share.
6. Have you loaded lm-sensors on your streamer and monitored the operating temps, or at least checked them in the BIOS?
No, I've not loaded lm-sensors nor checked the temp readings in the BIOS. The case only gets slightly warm after its been on for several hours.
FYI, when using the "top", hitting "1" will show the load for each of your two CPU cores as opposed to a single aggregate line.
Yes, I knew that.
A case with a a DC-DC psu for £40 (new or s/hand?) was a good deal.
I was wondering just how little CPU grunt you could get away with doing file transfer and audio playback, but actually I doubt whether there is any BIOS option to turn off a core.
You could try a "modprobe acpi-cpufreq". but perhaps "SpeedStep" is off in the BIOS if you have no frequency scaling. This would imply your CPU is operating at full tilt and max V core. So there's no potential to save energy. It would be interesting to know if you get the CPU working in a lower state and freq if it has any bearing on SQ.
A case with a a DC-DC psu for £40 (new or s/hand?) was a good deal.
I was wondering just how little CPU grunt you could get away with doing file transfer and audio playback, but actually I doubt whether there is any BIOS option to turn off a core.
I think Keith's case was a good deal as you say. I have yet to come across a BIOS that allows you to shut down a core, undervolt yes, but turn off a core is a new one on me. My current motherboard which includes 4GB RAM, 1 x SSD and an nVidea ION GPU (very power hungry) draws 43W at the wall. The new Intel board is going to draw around 10W - I would expect that a board of Keith's specs would draw around 20W or less, and the entire system around 25~30W without internal HDD's and only 2GB RAM.
Keith's case looks like this one
http://www.it-tech-uk.com/72-black-e-mini-q6-e-q6-mini-itx-aluminum-pc-case.html
Only Keith can vouch for the DC-DC PSU quality.
But, as like you, I estimated the overall system power draw to be around 30W, you might be able to get away with 90W power brick. I believe there are some Seasonic and FSP DC power bricks around with pretty high efficiency ratings.
It's a long time since I've used Intel kit, so perhaps BIOS with core control is limited to the AMD world. My current PC has a GA-880M-UD2H m/board with a quad core 960T. You can disable cores if you wish.
Tim, wlil you have your DN2800MT working soon?
Keith's case looks like this one
http://www.it-tech-uk.com/72-black-e-mini-q6-e-q6-mini-itx-aluminum-pc-case.html
Only Keith can vouch for the DC-DC PSU quality.
But, as like you, I estimated the overall system power draw to be around 30W, you might be able to get away with 90W power brick. I believe there are some Seasonic and FSP DC power bricks around with pretty high efficiency ratings.
It's a long time since I've used Intel kit, so perhaps BIOS with core control is limited to the AMD world. My current PC has a GA-880M-UD2H m/board with a quad core 960T. You can disable cores if you wish.
Tim, wlil you have your DN2800MT working soon?
Yes Chris, that's the one.
As to the quality of the dc supply, it's an unknown, but as I plan to play with a better supply in due course it is only a stop gap until I can afford to upgrade.
Tim, wlil you have your DN2800MT working soon?
That's a good question, its actually under review as I have been thinking about some differing options now, so no, its still in the box..... had it since August now and still haven't got around to it - where does all the time go :rolleyes: (that sounds like a good song title)
I am 'considering' going another route and buying a different case and power supply at the moment.
Keith,
After checking, I now realise "SpeedStep" is not a feature of the D525 ATOM. The N2800 on the DN2800MT Tim was thinking of using does have EIST.
(http://ark.intel.com/products/49490/Intel-Atom-processor-D525-1M-Cache-1_80-GHz)
I'm not sure what's going on here as they quote the CPU as having a Vid range of 0.8 to 1.175V. I suppose this relates to c states rather than p states.
I found this post which may offer some control over the CPU operating freq in Linux.
http://lukas.zapletalovi.com/2011/04/ondemand-governor-cannot-work-on-intel.html
I'm not sure it's worth messing with as any power saving is likely to be minimal.
Keith,
My old brain is getting addled, I stupidly forgot the obvious test which is to boot your Linux audio server with a maxcpus=1 option. Everything will run on a single core and it would be interesting to cf "top" output for CPU usage and see if this has an bearing on SQ from your audio server. In other words, would it have made any diiference if you were running on a single core ATOM CPU?
Tim,
I'm intrgued to know what alternatives you're exploring. If your DN2800MT is now redundant I might have a use for it. After a bit more googling, VoyageMPD Linux appers to run OK on this m/board. Power usage might not be a low as possible without the proper graphics driver, but it's still < 20W. Rather than using a mSATA card, you can get away with a 2 or 4GB CF card in a cheap SATA adapter, total cost around £15-20.
Thanks Chris. I'm now running with maxcpus=1 added to grub config. top confirms that only one cpu is being utilised at around 1 to 2 percent (as opposed to <1 percent when using all cores)
There are less active tasks and more free memory when limited to a single core too.
Sound quality? - couldn't hear any obvious changes on first listen, but i have a bad cold at the moment and don't feel my hearing is at its best right now. I'll do some more comparisons in due course and report back any conclusions.
Tim,
If your DN2800MT is now redundant I might have a use for it.
If I don't use it I'll let you know Chris, as it will go on eBay or be offered here. Its never been powered up yet, still not 100% what I'm going to do yet as I have some testing to do with what I have before I make a final decision.
Reid Malenfant
30-11-2012, 21:15
Just seen this! Wow, hats off to you Keith :D
Well done that man, brilliant!
Enjoy as I'm sure you are doing :cool:
Sound quality? - couldn't hear any obvious changes on first listen, but i have a bad cold at the moment and don't feel my hearing is at its best right now. I'll do some more comparisons in due course and report back any conclusions.
I hope your cold is soon gone. I had a real stinker last week and all sound has turned into a cross between rice crispies and having a sea shells clamped to your ears Now I've got to do battle with the dreaded earwax again, which is a royal pain.
If your in the mood for further experimentation, here's a collection of possible software tweaks for Linux and MPD:
https://sites.google.com/site/computeraudioorg/linux-for-audio
http://www.symphonic-net.com/kubotayo/articles/voyagempd.html#update
The second includes a kernel config supposedly fine tuned for ATOM and tips on how to use RAMDISK for playing from memory in MPD, real-time kernels and irq priorities and using OSS4 instead of ALSA.
Personally, I doubt if messing with RT will make any audible difference, particularly if you asked the question is real-time relevant for audio playback at somehwere like the "Linux musicians" forum. But if you have the time it's free to try.
I think you should give the Kernel idea a try. I recently installed the low latency kernel as a test of concept on Ubuntu and I'm pretty impressed with the results. I've not sanity checked it against the generic kernel yet, plus Ubuntu isn't a stripped out distribution so it may not be as effective if you are using one of those.
I think you should give the Kernel idea a try. I recently installed the low latency kernel as a test of concept on Ubuntu and I'm pretty impressed with the results. I've not sanity checked it against the generic kernel yet, plus Ubuntu isn't a stripped out distribution so it may not be as effective if you are using one of those.
The kernel in VoyageMPD is “low-latency”. The standard kernels used in Ubuntu and its derivatives are not, hence the need to install a new kernel. I wrote about this earlier in the year.
http://theartofsound.net/forum/showpost.php?p=292606&postcount=142
While the HPET timer is enabled in these kernel configs, you'd have to use the correct clocksource option at boot time to use it. Despite its name the HPET 's not necessary the fastest kernel time source, most systems will use use the time stamp counter (TSC). You can check with these commands:
To find your current clocksource
cat /sys//devices/system/clocksource/clocksource0/current_clocksource
To see available clocksources
cat /sys/devices/system/clocksource/clocksource0/available_clocksource
See:
http://en.community.dell.com/techcenter/b/techcenter/archive/2011/04/28/clock-accuracy-in-linux.aspx
http://www.chromium.org/chromium-os/how-tos-and-troubleshooting/tsc-resynchronization
The links a I gave Keiths included refs to real-time kernels etc., which are as much to do with determinism as low-latency. Conventional wisdom says while RT may be important in recording audio on computers, it's not relevant to playback. Yet some swear by a combination of RT kernels,.jack and brutefir. I'm sceptical.
No offence guys, but all this is why I avoid Linux. :)
No offence guys, but all this is why I avoid Linux. :)
Horses for courses, forget the "all this" and just go back to Keith's original post and his very neat solution.
The rest of it is just technobabble which you can safely ignore unless the finer points of Linux are of interest to you.
Let's not forget the highly popular SBT runs Linux and has been tweaked to hell and back.
By all means stick with Windows7/8 + jplay or whatever, but unless you've tried Linux you'll never know what you might have missed.
No offence guys, but all this is why I avoid Linux. :)
It does seem like I have just walked into a top secret weapons facility trying to sell a crossbow. :lol:
I haven't read all the linux thread so I will need to take a look, my Linux journey is still in its early stages.
Thanks for the information Krisbee. I tried looking the the irq's and they look pretty spread out and it looks like the TSC is used.
Just seen this! Wow, hats off to you Keith :D
Well done that man, brilliant!
Enjoy as I'm sure you are doing :cool:
Cheers Mark. It's a fun little project.
Great to see you back on here by the way.
I hope your cold is soon gone. I had a real stinker last week and all sound has turned into a cross between rice crispies and having a sea shells clamped to your ears Now I've got to do battle with the dreaded earwax again, which is a royal pain.
If your in the mood for further experimentation, here's a collection of possible software tweaks for Linux and MPD:
https://sites.google.com/site/computeraudioorg/linux-for-audio
http://www.symphonic-net.com/kubotayo/articles/voyagempd.html#update
The second includes a kernel config supposedly fine tuned for ATOM and tips on how to use RAMDISK for playing from memory in MPD, real-time kernels and irq priorities and using OSS4 instead of ALSA.
Personally, I doubt if messing with RT will make any audible difference, particularly if you asked the question is real-time relevant for audio playback at somehwere like the "Linux musicians" forum. But if you have the time it's free to try.
Thanks again Chris. I may well have a play with those in due course. At the moment I'm just enjoying playing music on it.
I'm just enjoying playing music on it.
Precisely, the rest is just a bit of a lark ....
Robert,
Glad you're giving Linux a whirl, look out for John's (Welder) post on using Linux.
Reid Malenfant
02-12-2012, 20:14
Cheers Mark. It's a fun little project.
Great to see you back on here by the way.
I'm sure it is fun, bet it puts a big smile on your face thinking about what you have achieved :D
Great to be back to, it's no fun being without a working computer :eek:
Enjoy the fruits of your labour.
Horses for courses, forget the "all this" and just go back to Keith's original post and his very neat solution.
The rest of it is just technobabble which you can safely ignore unless the finer points of Linux are of interest to you.
Let's not forget the highly popular SBT runs Linux and has been tweaked to hell and back.
By all means stick with Windows7/8 + jplay or whatever, but unless you've tried Linux you'll never know what you might have missed.
I have tried Linux Chris, didn't like it.
Quite involved in the SB Touch linux side of things actually, did a few of the UV meter screensavers :)
Naa..why over complicate things.
Each to their own though. :)
I have tried Linux Chris, didn't like it.
That's exactly what my mate said about work. He tried it once, and didn't like it.
That's exactly what my mate said about work. He tried it once, and didn't like it.
:lol:
I've programmed in it...and still think its pish!
:lol:
I've programmed in it...and still think its pish!
Well, if that's your considered opinion, all I can say is thankfully a lot of developers think differently.
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