Amigaworld.net - The Amiga Computer Community Portal Website

home

features

news

forums

classifieds

faqs

links

search

6108 members

Amiga Q&A / Free for All / Emulation / Gaming / (Latest Posts)

Login

Lost Password?

Don't have an account yet?
Register now!

Support Amigaworld.net

Your support is needed and is appreciated as Amigaworld.net is primarily dependent upon the support of its users.

Menu

Main sections

»	Home
»	Features
»	News
»	Forums
»	Classifieds
»	Links
»	Downloads

Extras

»	OS4 Zone
»	IRC Network
»	AmigaWorld Radio
»	Newsfeed
»	Top Members
»	Amiga Dealers

Information

»	About Us
»	FAQs
»	Advertise
»	Polls
»	Terms of Service
»	Search

IRC Channel

Server: irc.amigaworld.net
Ports: 1024,5555, 6665-6669
SSL port: 6697
Channel: #Amigaworld
Channel Policy and Guidelines

Who's Online

22 crawler(s) on-line.

95 guest(s) on-line.

1 member(s) on-line.

fricopal!

You are an anonymous user.
Register Now!

fricopal!: 24 secs ago

Hammer: 51 mins ago

nbache: 1 hr 18 mins ago

agami: 1 hr 59 mins ago

zipper: 2 hrs 24 mins ago

Kremlar: 2 hrs 34 mins ago

NutsAboutAmiga: 2 hrs 38 mins ago

DiscreetFX: 2 hrs 45 mins ago

OlafS25: 2 hrs 54 mins ago

Luc: 3 hrs 28 mins ago

	Amigaworld.net News : AmigaOne x1000 HD Audio Driver Complete
	posted by vox on 16-Jul-2013 4:12:30 (5896 reads)

blog.hyperion-entertainment.biz
Posted by Lyle Hazelwood on July 15, 2013

I am happy to announce the release of the finished HDAudio driver for the AmigaOne X1000! The driver now supports recording as well as playback. It also now supports S/PDIF optical output.

There have been questions about whether full “32 bit” audio really makes a difference. I’d like to dig a little deeper to better understand the technical specifications....
(Please click read more.)

There are two primary factors that contribute to the quality of a digital sound recording. One is resolution, or how many bits per sample, and the other is sample rate, commonly 44100 or 48000 samples per second.

As you look at the waveform of a sound recording, these two numbers determine the vertical and horizontal resolution of the wave.

I’ll begin with the “bit width” or vertical resolution.

The original Amiga’s sound output supported four channels at eight bits of resolution. Eight bits means there are two hundred and fifty six possible vertical “steps” that can be used as the wave is generated. Now we spread those steps across a -2 volt to +2 volt span and we get 0.015625 volts per step.

At the time of the Amigas introduction, that was a pretty fair sound playback. But only 256 steps is not as “high fidelity” as we might like. As a comparison, Compact Disk Audio is reproduced at 16 bits per sample. This makes for a big improvement in resolution. 16 bits offers us 65536 possible “steps” to spread across the -2 volt to +2 volt range. Now the step size is 0.0000610351562 volts per “step” of vertical resolution. So 16 bit audio is a HUGE increase in accuracy.

Getting back to our driver, AHIPrefs offers both 16 Bit HiFi and 32 bit HiFi modes. But I’ll bet that neither of those modes gives exactly what you might expect. As AHI mixes lots of different sounds together, possibly each sound with it’s own volume and pan settings, it can be useful to have more resolution available to work with. Here’s the clue: ALL AHI modes that say “HiFi” are sending 32 bit data out to the sound device! The “16″ and “32″ only describe what goes IN to the AHI mix routines. if it says HiFi, you WILL get 32 bit output to your card!

Or will you? In truth, while AHI is making it’s calculations using 32 bit registers and 32 bit math, it only promises 24 bits of accuracy. Is this anything to be concerned about? Not at all. I’ll tell you why. 24 bit samples will resolve to a “step size” of 0.0000002384185 volts per step. Wow! That is about one quarter of a microvolt. Those with an electronics background can probably tell you, that attempts to accurately work at those levels are just ridiculous. We have reached an accuracy that is beyond the ability of our amplifiers and speakers to reproduce. Put simply, 24 bits is the reasonable limit of current technology, or at least affordable technology.

So our 32 bit samples are flying out of AHI and in to the HDAudio codec. While the ”container” is 32 bits wide, even the “high definition audio codec” that we have in the AmigaOne X1000 only resolves the top 24 bits. So it seems that in the end, both AHI and HDaudio agree that 24 bits is the reasonable limit for now.

And how about sample rate or the “horizontal” resolution?

How rapidly a sound is sampled and played back can also have a BIG impact on sound quality. It all starts with the Nyquist-Shannon sampling theorem or more commonly the Nyquist theorem. It’s pretty simple. As you record an audio signal, you must sample at at least twice the frequency of the highest pitch being recorded. Any sound that is higher than half the sampling frequency will be converted to noise and nasty noise at that.

So how high do we need? It is generally held that human hearing range is from 20 Hz (cycles per second) up to 20000 Hz. So any frequency above 40000 should be great right? Well Yes and No.

One simple problem is that we still must filter out all sound above half the sample frequency, and most frequency dependent volume controls (graphic equalizers) work with gradual slopes. There is no “hard cutoff” at a certain frequency, so we need a bit of headroom.

But there is another reason. As a high frequency sound approaches the Nyquist rate, we are only sampling about once per half-cycle. While this will reproduce the frequency of the original, it will do it at a bare minimum of accuracy. In other words, as frequencies get higher, they get less detail.

So what does it really matter?
Audio CDs play back at 44100 Hz. Not bad at all.
Television/DVD audio is usually at 48000 Hz. Nice.
With the HDAudio chip in the X1000 we support both of those frequencies.
We also support 88200, 96000, 176400, and 192000.
So we can double or quadruple the sample rates of common media!

At first, I really thought it was all a numbers game, but when developing the driver, I can actually hear the noise decrease noticeably as the playback rates went up!

And that is where I’ll leave off. This was enough of a lesson for one day. I am very happy that I could contribute to the completion of this driver. And the chance to “raise the bar” regarding sound capability was really very nice icing on the cake.

Like many of us, I have been using Amigas for a long time. Today, right here in front of me is an Amiga that supports high definition audio, a modern high performance video card. It uses standard, off the shelf keyboard, mouse, monitor and many USB accessories as well. Most of these we unheard of in the classic days. But with all the new and shiny, it is still AmigaOS to the core.
:)

STORYID: 6817

Most read story about Amigaworld.net News
Official OS4 Screenshots from Hyperion

Last news about Amigaworld.net News
MailSender released

Goto page ( 1 | 2 )

Poster

Thread

nexus

Re: AmigaOne x1000 HD Audio Driver Complete
Posted on 16-Jul-2013 6:52:10

[ #1 ]

Regular Member

Joined: 11-Feb-2005
Posts: 430
From: Germany

Congratulations (to all of us X1000 owners ;) ) !
Well done, dude!
nexus

_________________
dye 'em black!

Status: Offline

Nibunnoichi

Re: AmigaOne x1000 HD Audio Driver Complete
Posted on 16-Jul-2013 6:54:09

[ #2 ]

Cult Member

Joined: 18-Nov-2004
Posts: 972
From: Roma + Milano, Italia

Thank you for the lengthy explanation... even though i don't have an X1K, it's very useful
Oh, and good job with the HD audio driver

_________________
Proud Amigan since 1987
Owner of various Commodore and a SAM440ep\OS4.1FE
See them on http://retro.furinkan.org/

Status: Offline

Hondo

Re: AmigaOne x1000 HD Audio Driver Complete
Posted on 16-Jul-2013 6:56:43

[ #3 ]

Super Member

Joined: 10-Apr-2003
Posts: 1370
From: Denmark

Thank you for the hard work. It's great the X1000 Amiga has High Definition sound

_________________
On Planet Boing Trevor is God

Status: Offline

olegil

Re: AmigaOne x1000 HD Audio Driver Complete
Posted on 16-Jul-2013 7:09:49

[ #4 ]

Elite Member

Joined: 22-Aug-2003
Posts: 5900
From: Work

quoting myself from the forum thread:
Quote:

I like how he's trying to reason with the audiophiles out there:

Quote:

Put simply, 24 bits is the reasonable limit of current technology, or at least affordable technology.

The fact of the matter is, "affordable" stops a bit short of 96dB SNR, which is what you can get at 16 bit (technically 6.02 times number of bits plus 1.761, if the signal is a true sinus of 100% amplitude, which doesn't make much sense for a recorded sound. Give it recorded music with enough headroom not to go into clipping and this drops significantly). "Reasonable limit" stops somewhere around 114dB SNR, at the broadcast standard of ±15V audio levels. That's about 19 bit. In broadcasting you use either 20 or 24 bit, depending on (at least sort of, in a simplified view) whether it's going into a mixer or going out to a consumer.

Add a volume control to your amplifier and you're already FAR below the 16 bit quantization noise SNR.

If you look at an amplifiers specification you'll most likely see both dynamic range and THD+N. THD+N of 0.1% means 60dB SINAD, which is the signal-to-noise-and-distortion. effective number of bits (ENOB) here is then (tada): 10 bits. That 8-bit output is starting to look pretty reasonable again, isn't it?

But still, higher numbers always makes us smile

_________________
This weeks pet peeve:
Using "voltage" instead of "potential", which leads to inventing new words like "amperage" instead of "current" (I, measured in A) or possible "charge" (amperehours, Ah or Coulomb, C). Sometimes I don't even know what people mean.

Status: Offline

amigakit

Re: AmigaOne x1000 HD Audio Driver Complete
Posted on 16-Jul-2013 8:33:25

[ #5 ]

Amiga Kit

Joined: 28-Jun-2004
Posts: 2651
From: www.amigakit.com

Thank you Lyle and Steven!

_________________
Amiga Kit Amiga Store
Links: www.amigakit.com | New Products | A600GS

Status: Offline

QuBe

Re: AmigaOne x1000 HD Audio Driver Complete
Posted on 16-Jul-2013 13:41:18

[ #6 ]

Super Member

Joined: 3-Dec-2006
Posts: 1075
From: Dunes of Uridia

This is a great achievement... X1000 owners rejoice!

Q!

"i am home"

Status: Offline

pavlor

Re: AmigaOne x1000 HD Audio Driver Complete
Posted on 16-Jul-2013 14:16:31

[ #7 ]

Elite Member

Joined: 10-Jul-2005
Posts: 9673
From: Unknown

Well done!

Status: Offline

fingus

Re: AmigaOne x1000 HD Audio Driver Complete
Posted on 16-Jul-2013 14:51:45

[ #8 ]

Cult Member

Joined: 20-Oct-2006
Posts: 747
From: Havixbeck / Germany

Cool!

Please update the Envy24HT-Driver to be on the same level as that here is.

_________________
I´m back in 2023 on Classic Amiga with my A1200/Blizzard1230IB@50Mhz, 32MB RAM, AmigaOS3.2 and ROMs, Indivision AGA MK3, Author of Amiga-Flipclock (OS4)

Status: Offline

Spectre660

Re: AmigaOne x1000 HD Audio Driver Complete
Posted on 16-Jul-2013 15:11:40

[ #9 ]

Elite Member

Joined: 4-Jun-2005
Posts: 3918
From: Unknown

@Fingus

Both the Envy24HT and CMI8738 drivers are good candidates for updates as new cards in PCI and PCIex1 are being produced with 5.1 and 7.1 channel audio .

_________________
Sam460ex : Radeon Rx550 Single slot Video Card : SIL3112 SATA card

Status: Offline

klx300r

Re: AmigaOne x1000 HD Audio Driver Complete
Posted on 16-Jul-2013 15:45:58

[ #10 ]

Elite Member

Joined: 4-Mar-2008
Posts: 3857
From: Toronto, Canada

Big Thanks Lyle

_________________
____________________________
c64-2sids, A1000, A1200T-060@50(finally working!),A4000-CSMKIII
! My Master Miggies- Amiga 1000 & AmigaOne X1000 !
mancave-ramblings
X1000 I BELIEVE

Status: Offline

Plexus

Re: AmigaOne x1000 HD Audio Driver Complete
Posted on 16-Jul-2013 16:26:47

[ #11 ]

Regular Member

Joined: 29-Sep-2003
Posts: 290
From: SWEDEN (Sverige)

Yeeeah I use the optical output now on my X1000 and its works great!

Amazing work and thanks to all involved!

Last edited by Plexus on 16-Jul-2013 at 04:27 PM.

_________________
AmigaOne X5000, AmigaOS 4.1 Final Edition Update 2 special super 2 cores prepared super edition v75 christmas speciale uniqe quadro prepared AmigaOS... TWO MORE YEARS IS NOTHING IF YOU BEEN WAITING SINCE 1994..

Status: Offline

ssolie

Re: AmigaOne x1000 HD Audio Driver Complete
Posted on 16-Jul-2013 17:58:16

[ #12 ]

Elite Member

Joined: 10-Mar-2003
Posts: 2755
From: Alberta, Canada

Note the original blog entry at http://blog.hyperion-entertainment.biz has some nice pictures to go along with the text.

_________________
ExecSG Team Lead

Status: Offline

Hondo

Re: AmigaOne x1000 HD Audio Driver Complete
Posted on 16-Jul-2013 20:34:48

[ #13 ]

Super Member

Joined: 10-Apr-2003
Posts: 1370
From: Denmark

@Solie

Are we talking about the cake ?

_________________
On Planet Boing Trevor is God

Status: Offline

TrevorDick

Re: AmigaOne x1000 HD Audio Driver Complete
Posted on 17-Jul-2013 4:23:01

[ #14 ]

Elite Member

Joined: 30-Dec-2004
Posts: 2678
From: Wellington

Well done Lyle (and Steven). We salute you.

TrevorD

_________________
No, I don't need no reason, I'm just breezin'

Status: Offline

Slayer

Re: AmigaOne x1000 HD Audio Driver Complete
Posted on 17-Jul-2013 7:45:23

[ #15 ]

Regular Member

Joined: 4-Jan-2005
Posts: 416
From: New Zealand

Nicely done!

Great Stuff and Many thanks!

_________________
~Yes I am a Kiwi, No, I did not appear as an extra in 'Lord of the Rings'~
1x AmigaOne X5000 2.0GHz 2gM RadeonR9280X AOS4.x
3x AmigaOne X1000 1.8GHz 2gM RadeonHD7970 AOS4.x

Status: Offline

samo79

Re: AmigaOne x1000 HD Audio Driver Complete
Posted on 17-Jul-2013 8:45:55

[ #16 ]

Elite Member

Joined: 13-Feb-2003
Posts: 3505
From: Italy, Perugia

Well done

_________________
BACK FOR THE FUTURE

http://www.betatesting.it/backforthefuture

Sam440ep Flex 800 Mhz 1 GB Ram + AmigaOS 4.1 Update 6
AmigaOne XE G3 800 Mhz - 640 MB Ram - Radeon 9200 SE + AmigaOS 4.1 Update 6

Status: Offline

gregthecanuck