Computer based Hifi

[boris81]

The AMD Fusion series sound very well suited for the task. I haven't tried them out yet but on paper they seem to fall in the golden middle between the Atom and the iCore. I think the most important features you need to consider are multi-core and HD-capable video(if you will be using it). 2 years a go I built a totally silent iCore system with no fans or spinning hard drives. The AMD Fusion should make the task much easier and cheaper.

http://www.diyaudio.com/forums/multi-way/183879-pc-crossover-software-4.html#post2486325

 

[cha_indian]

Thanks for the reply boris! My plan is to build music PC...i am not interested in Video nor Dolby nor THX or multichannel audio. I want a pure old school Stereo source to feed my Stereo amp and tower speakers ... There is a passively cooled motherboard called Asus E35M1-M Pro. Still looking for a HiFi component like cabinet that can take a Asus Xonar Essense STX sound card. Please let me know if you find any suitable cabinet.

thanks,

 

[ChrisA]

Sorry for waking up such a old thread!

I am looking to build a Music HiFi s using a AMD Fusion 350 processor motherboard and Asus Xonar Essense STX sound card after reading a lot about Xonar card. My plan is to store all my music, listen to internet radio etc. I hope to retire my popcorn hour which i was using for this purpose.

Looking forward to your replies...

Seems a lot of work when you could simply buy an iPod and an Airport Express. The shirt pocket size, wireless remote and touch screen control would be hard to build yourself. The sound quality is near perfect if you use the fiber optic S/PDIF output on the Airport Express, It is all lossless digital until the signal gets to your DAC. Total cost is about $300. The limit is the storage, the ipod holds only up to 64GB and maybe you have more music than that? If you then you'd need a computer also in the system.

If you must build something you'd get a little better audio for less $$ with something like this PreSonus. It has a pretty good headphone amp and balanced in on out. And alaog gain controlls

You don't see many Asus cards of recording studios but you do see lots of Presonus, Apogee or MOTU stuff.

One thing that is VERY important are analog volume controls. Any digital control will reduce the dynamic range. It has to, it's something engineers can't work around.

 

[Javin5]

There is a passively cooled motherboard called Asus E35M1-M Pro

There is also an Asus E36M1-I Deluxe. This has built-in WiFi, so you can remotely control the unit and your playback with an iPad or similar tablet.

I´m planning to use this mini ITX board with an SSD for the operating system and the programs. The music files will reside on a external eSATA connected 2 GB HD. Audio will be taken from a USB port to an asynchronous USB-DAC.

Music download and CD-ripping will be done on the office PC, where all music files go to a 2 GB Backup HD. The HD on the living room E35M1 is then simply updated from time to time. This concept has the following benefits:

- No network is required (apart from the WiFi connection to the iPad controller)
- No keyboard, mouse and display monitor are needed in the living room.
- No server or network or other PC must be switched on to hear music
- No TV must be switched on to navigate on its screen with an infrared controller
- An iPad tablet should be sufficient in display size for comfortable navigation
- The E35M1 music PC is absolutely silent and can use a silent, fanless power supply
- The attached (encased) USB disk is almost silent
- The (cheap) 2 GB HD should hold my entire music collection in lossless wav

I have not yet found the following:

- The ideal case
- The ideal combination of music player software plus iPad remote control software

As this project is still in the early planning stage, I can´t be of much help yet, as far as practical experience is concerned. However, I´m confident, that the E35M1 is well suited for this task. Due to the built in WiFi, the Deluxe version has about 2 Watt more power dissipation than the Pro, but should still be ok to operate without a case fan, but I would not enclose it in a tight cabinet.

 

[ChrisA]

- The ideal combination of music player software plus iPad remote control software.

the iPad itself can play music to remote speakers. It can also access music on a remote disk. or from it's own flash ram. They all come with this ability right out of the box. Notice if you do happen to have some remote speakers there is an option at the lower right to select which speaker to send the music to.


This is a bit like wanting to write a "phone app" for your iPhone.

 

[i2k92]

Music server is a cheap & very comfortable way to enjoy music, providing that you understand how to play around with the OS adn software to apply necessary optimisation.

I documented the build of my music server here :
http://www.diyaudio.com/forums/pc-based/193331-my-poor-man-music-server.html

I think it can fulfill the design goals on the post above, except iPad as I don't have one..I'm an android fan, so having iPad is a heresy

Initially I used a simple & cool Atom 410 which is more than enough to do the task. I replaced it with MSI E350 board as the MSI has coax output which sounds better thru my DAC compared to old board USB interface. The new board has fans on the CPU cooler, but I can hardly hear it. Pico PSU is on the way to replace the internal PSU, I believe this upgrade can make the PC runs cooler & more silent.

Look for music player software which support uPNP protocol (foobar, j.river, etc) to be able to control it remotely via Android or iPad. I don't know about iPad, but there are some very good and free uPNP remote controller on the Android market.

 

[Javin5]

ChrisA:

Thanks for your comments. As I mentioned, I need about 2 TB to store my music; it can thus not be stored and played directly from an iPad. And I don´t have a network with WiFi accessible NAS storage, nor do I have remote speakers. I definitely want to use a USB DAC, where the DAC clock is the master clock (no PLL, less jitter).

i2k92:

Thanks for your reply and for the link, I'm certainly going to read your posts. As far as remote control is concerned, I'm not fixed regarding the iPad, any other tablet (probably Android based) of the same size and resolution would be fine as a remote controller. Regarding the Pico PSU, some have a fan on the external AC brick, no idea how loud they are.

 

[boris81]

Javin5,
I found an AC/DC brick capable of 150W without a fan. You just need to match the specs for the picoPSU. I suspect that with the AMD Fusion anything over 100W will be an overkill although more headroom is always better.

I'm looking into writing an Android app to control my Windows PC remotely. The project is still in the planning phase and may never reach completion but I'll publish whatever I get done on DIYaudio. There are probably a bunch of people interested in this and I'm take suggestions.

 

[Javin5]

boris81:

80-100 Watt should be enough. What is the fanless unit you found (brand, model)?
Aren´t there already existing Android apps for remote Windows-PC control?

 

[boris81]

The AC/DC unit is: ea11803a-120. I can't remember where I bought it from but it came together with the picoPSU. It works great.
I saw that some Android apps are utilizing the Window Remote Desktop interface but I didn't try that yet. I'm thinking of writing my own app mostly for the fun of it. I use a remote for the volume so I only need to get up and walk to the computer when loading music.

I also realized there are ways to control Winamp remotely. Here is one web site interface that should work fine on a phone.

 

[i2k92]

boris81:

80-100 Watt should be enough. What is the fanless unit you found (brand, model)?
Aren´t there already existing Android apps for remote Windows-PC control?

Even 60w is enough, some reviews mentions that Fusion power consumption on max load is still below 40w. In case of music server, it is important to disable unnecessary peripheral and services so the consumption should fall below the number above.

Using remote desktop with a tablet is IMHO dreadful, due to small screen and touch interface. To do basic remote task (shutdown, manage services, etc) I uses OneID over the android, if I need to remote the server's desktop I use my laptop (which is rarely necessary).

 

[qusp]

One thing that is VERY important are analog volume controls. Any digital control will reduce the dynamic range. It has to, it's something engineers can't work around.

yeah kinda like how engineers cant get past the fact that reducing the volume with ANY system results in lower dynamic range; its kinda what the whole thing is about

i think youve probably missed the last few years. when volume control is operating at 40bit or 64bit like quality implementations are now, you will not come anywhere near the same LACK of impact on the DNR with an analogue control

 

[phofman]

i think youve probably missed the last few years. when volume control is operating at 40bit or 64bit like quality implementations are now, you will not come anywhere near the same LACK of impact on the DNR with an analogue control

What matters are MSBs, not LSBs, since LSBs will be dropped before entering the maximum 24bit DACs with S/N resolution of 20bits max. Volume control in more than 24 bits brings no benefits (the first 24bits will be the same no matter how many further lower bits are used in the division, perhaps one more for dither calculation, but the 24th bit is below any real-world resolution anyway). Volume control in 32bits makes sense due to native numerical formats of CPUs. But the 64bit volume control is a nice selling point for commercial audio players developers

DSP calculations are another story since they involve thousands of multiplications by often miniscule coefficients and additions on each sample where rounding errors at LSBs accumulate. Volume control is a single operation of dividing each sample by a static reasonably-sized number.

 

[qusp]

you misunderstand me, the dacs i'm talking about, like sabre 9018 (which is multichannel of course), the new AKM 32 bit parts, etc have an internal DSP/filter section which acts independently to the dac, also the DSP in my multichannel usb-i2s and also in completely software DSP. they all have integrated volume controls and i'm afraid the bits DO matter to the effectiveness and in some cases steepness of the filter (depending on the application), of course theres no free lunch, but compared to even the best analogue controls there is very little impact. channel matching is perfect all the way through the range, impedance is not effected, no extra parts are in the signal path, its far cheaper, it can be controlled in any number of ways including remotely, it doesnt wear. you can control as many channels as you want with one number etc etc.

analogue controls add noise of their own, the more you turn them down, but they attenuate the input noise, so DNR is impacted in 2 ways, digital the noise stays the same with respect to the signal, so when turned right down the ratio is of course higher, but given a noise floor that is low enough not to matter its a non-issue.

 

[phofman]

I am not saying digital volume control is inherently worse than the analog one. My argument is that more bits in volume control do not raise the headroom since the actual DAC circuitry does not transfer more than 20 most significant bits of resolution. No matter what is the number of bits below this level, some are hidden in the noise, the rest is dropped before entering the DAC.

DSP is performed before volume control, so that calculations are carried out on maximum information possible.

32bit DACs are built for convenience since 32 bit samples are natural language of CPUs, many transfer mechanisms (e.g. PCI controllers, Intel HDA) work at 32 bits only, and the samples had to be converted down to 24 bits before entering older 24-bit DACs. The actual resolution of 32bit DACs is the same as that of 24bit DACs, in fact I presume the actual DAC circuitry ignores the last 8 bits as it is way below physical resolution of the circuit and implementing them would be waste of energy and resources. And from outside of the chip only an electron microscope could tell

 

[qusp]

no, you really still dont get it. you have read some, but not all and understood some, but not all of what i said. lumped some bits in together, when i was talking specifically about something similar but different. i suggest you reread it, the 40 bit control i mentioned is NOT EVEN IN the DAC, neither is the 64bit, they are part of a multichannel usb-i2s convertors DSP and a piece of DSP software respectively. so i'm afraid they very much DO provide more bandwidth for the digital volume control, Crossover steepness and noise shaping filter. i'm just finishing up a multichannel digital XO, with dedicated individual i2s->dac->amp->driver path, the volume and filter are inseparable and calculated at the full bandwidth.

sabre also has one 256 step volume control, i spoke less of this, but there are all manner of processes running in it at higher bit depth and often at much higher bitrate if async is in use. it is a collection of parts in the one unit, the DSP and FIR filter section is actually operating at 48bit. i suggest you read this for some insight.

also the intel codec has little to do with 32bit support, 32bit float PCM has been in use on macs for years for audio mixing purposes

 

[phofman]

I do not argue about DSP. All I am saying is that doing volume control in significantly more bits than physical resolution of the DAC circuit gives no advantage since only as many most significant bits as is the resolution of the DAC will be used in the end and the rest of the bits will be dropped. If you disagree, please show us an example where this does not hold. I do not know of any since this is simple logic.

Merry Christmas