HiFi & Professional Audio Forum  

Kako da kompjuter zasvira tj. HTPC & DAC how-to

A/V risiveri, DVD / Blu-Ray plejeri, (O)LED i LCD paneli..

Topic author
speedym
Nov korisnik
Nov korisnik
Posts: 20
Joined: 08 Jul 2010, 20:29

Re: Problem sa svetlostnim dimmerima i audio sistemom

Post by speedym » 14 Jul 2010, 12:29

Gerner,

A friend has PowerBook Mac + external DAC - excellent results.

I'm going to try micro-ITX with no fans / no HDDs + external DAC - will see if a PC can match "the sound of Mac". Fan-less linear supply would be great, but is hard to find.

Cheers! :innoc


Topic author
speedym
Nov korisnik
Nov korisnik
Posts: 20
Joined: 08 Jul 2010, 20:29

Kako da kompjuter zasvira tj. HTPC & DAC how-to

Post by speedym » 15 Jul 2010, 01:42

(nastavak diskusije sa: http://www.audiohard.com/phpBB3/viewtop ... 489#p15489)

Gerner,

I agree with your point about PCs having a 'harsh' sound signature. I would be curious if those are due to unwanted harmonics in D/A conversion, or higher noise floor due to EMI / switching PSU inside the PC case, or perhaps due to the clock on the PCI sound card(s) being jittery.

On the other hand, I hope/think a well made external DAC with good quality D/A chip, input re-clocking, jitter-minimized internal clock and separated power lines could solve most of those issues w/o refraining to big sound buffers, and sending the data via unorthodox protocols. I'd like to play stereo, 5.1 HD movies and play games on the same system, and buffers causing sound latency can be a big issue there. Basically, what I'm trying to say is that, IMHO, they shouldn't win you any SQ if other parts of the DAC are well done.

Pls, do keep in mind that I'm just hypothesizing, and until I try and hear buffered and unbuffered DAC implementation to cross-compare, this is all talking out of my ass.

Cheers!

ps. Couple of nights ago, I was watching Battlestar Gallactica HD with a friend, a we were amazed that a solid sounding sound system can offer a better viewing/listening experience then the sound in most of the Belgrade's cinemas. :shock: I was short of amazed, at that moment, so, you know, that's where I come from and would like to go further.


sdanicic
Audio Expert
Audio Expert
Posts: 2474
Joined: 16 Mar 2006, 13:46
Location: Beograd

Re: Kako da kompjuter zasvira tj. HTPC & DAC how-to

Post by sdanicic » 15 Jul 2010, 09:59

Admin note:

regarding request for split of HTPC topic - at the moment I'm over-utilized with regular business activities on project I'm currently running, so I don't have time to participate on Forum.

Please feel free to open new topics and run discussion according to your needs.

Cheers :mr

User avatar

PrekoBare
srebrni korisnik
srebrni korisnik
Posts: 538
Joined: 03 Dec 2008, 20:39

Re: Kako da kompjuter zasvira tj. HTPC & DAC how-to

Post by PrekoBare » 15 Jul 2010, 15:52

speedym wrote: I'd like to play stereo, 5.1 HD movies and play games on the same system, and buffers causing sound latency can be a big issue there. Basically, what I'm trying to say is that, IMHO, they shouldn't win you any SQ if other parts of the DAC are well done.
Speedy, slazem se sa vecinom stvari koje si napisao, pa ajde da napisem po nesto sa cim se mozda neces sloziti ali cete verovatno zainteresovati da sam proveris. (Unapred se ogradjujem jer sam na "onom" forumu 5 godina bezuspesno gurao neke stvari pa znam kako to obicno ide).

Digitalna tehnika a pogotovu ona koja ukljucuje PC je tehnika uz pomoc stapa i kanapa (kao sto je bio VCR na primer). Ja to zovem nezrela tehnologija. Konacno resenje ce biti verovatno nesto drugo od ovog koje danas koristimo. Ali posto zivimo danas, treba da izvucemo maksimum od onog sto danas moze da se nabavi, a da pri tome potrosimo sto manje.

Ima jos faktora koje nisi naveo. Pokusacu sve da ih pobrojim, izvini na ponavljanju.


1. Strujno napajanje - treba razmotriti u celini i za svaki uredjaj posebno, pre svega da li "uzvodni" uredjaji ubacuju smetnje za one nizvodne.

2. EMI i RF - svi pokretni delovi prave magnetno polje (n.pr ventilatori, hard drajvovi) i to treba uzeti u obzir prilikom fizickog razmestaja komponenti.

3. Vibracije - sve su negativne kad se ticu hardvera. Treba ih napasti na makro i mikroplanu.


Kad je ovo temeljno razmotreno, treba posmatrati sistem PC - konekcioni kabl - DAC kao jednu celinu, pa ga rasciniti na delove:


4. PC hardver kao izvor navedenih smetnji. Razmotriti optimalan odnos grejanja komponenti (performanse sistema) i hladjenja (tisina, otklanjanje vibracije
izazvane ventilatorima i obrtno magnetno polje)

5. Operativni sistem optimizovan za audio plejbek (to je kao stelovanje ventila na motoru)

6. softver optimizovan za audio plejbek (to je kao balansiranje tockova )

7. s/w plejer (zvuce razlicito)

8- tip fajli koji se koristi (nekompresovani wav ili lossless flac, wv, ape, apple - zvuce razlicito. Redbook ili hi-rez? )

9 - odakle fajla svira - sa hard drajva, sa memorijske kartice ili memorijskog bafera?

10 kako se digitalni signal eksportuje u DAC ? (USB, firewire, COAX, toslink, CAT6? ) Moje misljenje (za moje pare) je da je USB2 za audio corsokak. Gernerov pristup mi se cini kao jednino do sada prihvatljivo resenje koje sam video koje pokusava da otkloni osnovne probleme koriscenja USB.

11. DAC (srce svega)

Iz gore navedenog je jasno da PC ne moze biti optimizovan i za audio i za HT i za igrice, jer su to potpuno razliciti zahtevi. Moze gaming PC da svira muziku, ali to nece biti audiofilsko resenje. A audiofilski PC je nula kao gaming PC. HT je negde izmedju.

Srednje resenje je dual - boot PC. Jedan OS optimizovan za audio, drugi za sve ostalo.

Po mom iskustvu netbook sa bateriskim napajanjem moze da bude cudo od audio plejera za smesne pare pa i o toj opciji treba razmisliti. Netbook kao audio plejer, PC za sve ostalo.

Neposredni rezultat mog dugogodisnjeg bavljenja PC kao izvorom zvuka je CD plejer vise ne koristim a da gramofon slusam vise nego ikad :-)
"Najbolje je neprijatelj dobrog"

Volter

User avatar

PrekoBare
srebrni korisnik
srebrni korisnik
Posts: 538
Joined: 03 Dec 2008, 20:39

Re: Problem sa svetlostnim dimmerima i audio sistemom

Post by PrekoBare » 15 Jul 2010, 17:34

Gerner wrote:
•T USB Audio is different (USB -> DAC):
•Bulk USB mode, USB High Speed and big 100ms buffer in DAC <> no data loss, data guaranteed correct (bit for bit)
•Asynchronous data transfer and ultra low phase noise master clock at data destination (DAC) <> no influence on sound (only clock jitter of master clock)
•No sample clock recovery <> Sample clock of the DAC controls data stream from the PC > no influence on sound (only clock jitter of master clock)
•Quality of PC and USB cable <> no influence on sound (only clock jitter of master clock)
•No audio processing under Windows. PC software only copies audio data from HD to the DAC directly <> no influence on sound
•Decoupled and galvanically insulated clock domains <> jitter is reduced to the inherit levels of the master clock
•Significantly improved TD technology (TD PRO Core – without data manipulation etc.) <> improved sound quality in direction analog, battery supply unnecessary
•0.8mm/4 layer ultra high speed printed circuit board <> sharp and crisp digital signals <> decreased jitter
•Ultra low noise design, optimal decoupling of supplies and IC <> decreased jitter
•Custom designed high speed IC <> decreased jitter
•Optimal decoupled digital and analog domains <> Analog domain stays clean

LP
G :D
Gerner, can it play 96/24 or higher?
"Najbolje je neprijatelj dobrog"

Volter


Topic author
speedym
Nov korisnik
Nov korisnik
Posts: 20
Joined: 08 Jul 2010, 20:29

Re: Kako da kompjuter zasvira tj. HTPC & DAC how-to

Post by speedym » 15 Jul 2010, 21:25

PrekoBare,

Da, slazem se oko generalnih principa i stavki koje pominjes. Kada si to sve lepo nabrojao, da iskoristim priliku da prodiskutujem par detalja.

Za pocetak, sto se tice perspektive gledanja na PC - lepota, a istovremeno i prokletstvo, PC platforme je u tome da moze posluziti za najrazlicitije namene, a zbog otvorenosti specifikacije, mogu se napraviti i razliciti kompromisi u izgradnji. Generalni princip je da cena bude sto niza, time i, razumljivo, sve te funkcije sto dostupnije ljudima, ali se svakako usput gubi na kvalitetu. Takodje, software je pisan na slican nacin i Microsoft se uopste nije proslavio u tome sto radi.

Mislim da faktori implementacije u praksi ostavljaju utisak nedorecenosti i nezrelosti (stapa i kanapa) koji pominjes, i, dakle, generalno se slazem oko toga.

Sa druge strane, ozbiljniji PC-ji u rack mount serverskim izdanjima sa linux/unix OS-ovima su potpuno druga prica, i pokazuju da je na PC platformi moguce izgraditi i solidan uredjaj.

Ono sto mi je zanimljivo, u diskusiji se tvrdi da wav i flac ne zvuce isto, takodje da winamp i foobar ne zvuce isto, sto je meni prilicno neverovatno. Takodje mi je neverovatno da od medijuma (HDD, data CD, flash) zavisi kvalitet zvuka. Osecaj mi kaze da se to svodi na bagove u software-u i na lose uradjeno razdvajanje onoga sto prima DAC od onoga sto salje PC, ako je to uopste moguce razdvojiti u potpunosti, tj. srediti signal tako da se inherentni problemi PC-ja 'ne cuju'.

Trenutno sam misljenja da vecina tih problema mogu da se rese pustanjem preko LAN-a, izbacivanjem rotacionih komponenti iz HTPC sistema, i dobro uradjenim DAC-om. Ali, time will tell. Mozda i ja na kraju zavrsim na MacBook-u ili nekom dedicated/buffered uredjaju kao Gerner. :cafe


Topic author
speedym
Nov korisnik
Nov korisnik
Posts: 20
Joined: 08 Jul 2010, 20:29

Re: Kako da kompjuter zasvira tj. HTPC & DAC how-to

Post by speedym » 18 Jul 2010, 01:30

Tja, isprobao sam, foobar stvarno zvuci bolje nego winamp. Razlika se jasno cuje, pogotovo bolje definisan zvuk u nizim frekvencijama. Koji blam za winamp, posle 10+ godina razvoja.. verovatno imaju bug u FLAC dekoderu ili DS outputu.

ps. Nisam primetio razlike izmedju Foobar "Direct Sound" i "Kernel Streaming" moda.


RIVIERA
srebrni korisnik
srebrni korisnik
Posts: 356
Joined: 18 Jan 2009, 20:45

Re: Kako da kompjuter zasvira tj. HTPC & DAC how-to

Post by RIVIERA » 18 Jul 2010, 12:02

Hi Fellows
(hello to Gerner and Speedy)
:oky
I am here
will reply latter, have to go, cheers


Topic author
speedym
Nov korisnik
Nov korisnik
Posts: 20
Joined: 08 Jul 2010, 20:29

Re: Kako da kompjuter zasvira tj. HTPC & DAC how-to

Post by speedym » 20 Jul 2010, 17:58

Cheers, maestro Riviera! Welcome to our HTPC mussings. ^_^

@Gerner: Heh. I'm amusing myself with an almost-vintage mazda sport car these days. If I manage to fix it, we'll be in VS in a jiffy. It's quite adorable but in an awkward condtition, will require a lot of work to bring her up to speed. Pic: http://speedy.rs/pics/IMG_0136%20small% ... 0plate.jpg


Topic author
speedym
Nov korisnik
Nov korisnik
Posts: 20
Joined: 08 Jul 2010, 20:29

Re: Kako da kompjuter zasvira tj. HTPC & DAC how-to

Post by speedym » 25 Jul 2010, 19:58

Just a short update - friend and I did some improvised A-B testing between foobar & winamp playing flac, and although I thought I could distinguish the difference, seems it's very hard. The second test, between .mp3 320k CBR and .wav was much easier to distinguish. MP3 sound signature adds roughness / peaks to the vocals. (sq is not that bad considering the file is 1/5 of the original size, 5:1 compression)

I'm curious about winamp vs. foobar because I was positive I heard the difference previously, esp. in the bass definition.

@Gerner: I'll drop by waaay-waaay before 'zito and sitni kolachi' day, no worries!! :oky


Topic author
speedym
Nov korisnik
Nov korisnik
Posts: 20
Joined: 08 Jul 2010, 20:29

Re: Kako da kompjuter zasvira tj. HTPC & DAC how-to

Post by speedym » 12 Sep 2010, 03:06

I've tried playing music from a brand new HP ProBook laptop, Windows 7, run from battery - noise floor is lower then my amp's very quiet hissing noise when it is idle. Laptop analog output sounded ok, but needs more testing - i'll update this thread when I test it some more.


sdanicic
Audio Expert
Audio Expert
Posts: 2474
Joined: 16 Mar 2006, 13:46
Location: Beograd

Re: Kako da kompjuter zasvira tj. HTPC & DAC how-to

Post by sdanicic » 12 Sep 2010, 10:07

speedym wrote:I've tried playing music from a brand new HP ProBook laptop, Windows 7, run from battery - noise floor is lower then my amp's very quiet hissing noise when it is idle. Laptop analog output sounded ok, but needs more testing - i'll update this thread when I test it some more.
Sta se podrazumeva pod tim "tried" - ako moze malo vise detalja?


Inace u letnjem dvobroju WHF-a sam pisao uvodni tekst o trenutno najjacoj seriji HP laptop racunara - Envy, model Envy 17. Prema dogovoru sa urednikom, nadam se da ce do kraja godine biti uradjen jos jedan test gde ce se malo detalnjije istestirati funkcionalnosti vezane primarno za audio i DVD/Blu-Ray sekciju.


Topic author
speedym
Nov korisnik
Nov korisnik
Posts: 20
Joined: 08 Jul 2010, 20:29

Re: Kako da kompjuter zasvira tj. HTPC & DAC how-to

Post by speedym » 12 Sep 2010, 17:48

Za sada nisam radio listening testove, samo sam ga prikljucio, poslusao prag suma, pustio par pesama da se vrte u pozadini dok sam radio nesto drugo.. Nisam obracao paznju na kvalitet zvuka, ali nista ocigledno nije bilo lose.

Svidja mi se nizak nivo suma na audio out-u, jer to daje solidnu osnovu da se na njega zakaci dobar externi DAC preko firewire-a (za stereo) a CPU/GPU je dovoljno mocan da se usput moze koristiti i kao HTPC za pustanje videa.

Post Reply