Which sound frequency setting is closest to original Amiga

[rsn8887]

First of all thanks to Toni for the best WinUAE yet! The no latency Vsync mode is a gift from heaven!

Just thought I'd ask about this in case somebody knows in here:
What is the max. sound frequency of a real Amiga 500 and 1200? Which WinUAE sound frequency gives the closest approximation of the real sound?

I would be astonished if the real thing was able to to 48 kHz, but maybe I am wrong. I have read conflicting statements on the internet about the best value for this setting, and thought I'd just ask in here.

I think the sound is maybe "too clear" at 48000, so I set mine to 44100. But it would be cool to be able to set it to a value that's the closest to a real Amiga.

Maybe it's just me but somehow I feel my old Amiga 500 output sound had more "ooomph" than my pc, and that was on a crappy boombox back then.

I don't think this has anything to do with emulation, since there are no scratches or other sound artifacts, and I am using asio4all. Are pc soundcards just worse than Amiga sound, or is there some analog magic in an Amiga that can hardly be emulated, like on the C64?

[musojon74]

The Amiga was a bit different in that each sound channel had a variable frequency. They could play up to about 22khz ish (someone will give exact number) when using tv screenmodes and a lot higher using scan doubled modes. The pc just mixes as many sounds as required into the sample rate on your card. Since they'll never match up exactly you want the highest mixing rate you can get and leave the emulation to do what it does. Have fun :-)

[Toni Wilen]

Yeah. Most likely reasons are:
- filter emulation disabled (A500 always filters the audio, led on = lots of filtering, led off = less filtering)
- different quality audio equipment
ADDED:
- quality of analog signal path inside Amiga may not that good vs completely digital in emulation.

[thomas]

Originally Posted by musojon74

The Amiga was a bit different in that each sound channel had a variable frequency. They could play up to about 22khz ish

The Amiga's hardware can go up to a bit more than 28 kHz for normal screen modes and even twice as much on AGA chipset with double scan screen mode activated.

[LocalH]

The same is possible with ECS Denise and the use of a faster horizontal scan rate.

[Doc Mindie]

In emulation, I usually set the reate to 22.5, as I think it sounds more like a "real" amiga than 44.1 and those... mayhaps that's just my ears been wonky

[Photon]

Heh, at first I misread this question. Anyway, select the next higher rate that the emu+your card support, above 28867 Hz, and you can be sure you can hear the max. quality the Amiga can muster. Note that there are specialized (demo/mp3) players that can do > 28867 Hz and > 8-bit, but for ordinary uses the above makes sure you don't make high quality sound work on Amiga sound worse than it is.

If you never watch modern demos in WinUAE, you can safely set the frequency to 22050 Hz without missing anything. PAL/NTSC max frequency is much higher than has been used in 99.99% of games, old demos, etc so far.

[daxb]

I havn`t experiences with WinUAE but I guess it is just the max. mixing frequency you can set (and no effect process between). If that is right you should use best value that your sfx card supports. In case of a classic game the source sfx qualtity is 8bit <=28kHz (except games that support AHI). This source will be send to/through your sfx card. If 44,1 or 48kHz frequency is set the output sound quality is technically 44,1 or 48kHz but should sound like original source (8bit <=28kHz). This means you cannot get better quality by seting WinUAE frequency higher then the source quality is. But you can shrink qualtiy by lower WinUAE frequency a lot (< 22kHz).

If this is wrong please let me know.

[khph_re]

Originally Posted by Photon

If you never watch modern demos in WinUAE, you can safely set the frequency to 22050 Hz without missing anything. PAL/NTSC max frequency is much higher than has been used in 99.99% of games, old demos, etc so far.

Unless you listen to ADPCM or MP3's from demo's or CD's. Then you might want to run them in the double scan mode.

[musojon74]

Originally Posted by daxb

I havn`t experiences with WinUAE but I guess it is just the max. mixing frequency you can set (and no effect process between). If that is right you should use best value that your sfx card supports. In case of a classic game the source sfx qualtity is 8bit <=28kHz (except games that support AHI). This source will be send to/through your sfx card. If 44,1 or 48kHz frequency is set the output sound quality is technically 44,1 or 48kHz but should sound like original source (8bit <=28kHz). This means you cannot get better quality by seting WinUAE frequency higher then the source quality is. But you can shrink qualtiy by lower WinUAE frequency a lot (< 22kHz).

If this is wrong please let me know.

This. Because pcs have to use mixing whereas the Amiga could do individual changeable sample rates per channel. As an example play a 4 channel mod through Soundstudio in 4 channel mode. Perfect. Now do it in mixing mode and check out the aliasing ( buzzy sound quality issues ). Using low rate on a pc is equivalent to using mixing mode for all audio. So hence why it shouldve nice and high and stay out of the way. For the real audio techies we don't want that nyquist limit being brought down to mess up our less affected Amiga channels. :-)

[clauddio]

I tried several frequencies on winuae and the most accurate I found is 32000

[Photon]

Originally Posted by musojon74

This. Because pcs have to use mixing whereas the Amiga could do individual changeable sample rates per channel. As an example play a 4 channel mod through Soundstudio in 4 channel mode. Perfect. Now do it in mixing mode and check out the aliasing ( buzzy sound quality issues ). Using low rate on a pc is equivalent to using mixing mode for all audio. So hence why it shouldve nice and high and stay out of the way. For the real audio techies we don't want that nyquist limit being brought down to mess up our less affected Amiga channels. :-)

Nothing to do with Nyquist frequency, and mixing is to 16-bit or higher on PC, so 4 channels x 8 bit will fit easily without aliasing. I think you can set any frequency and subjectively hear that something is better or worse, but >= 28867 ensures you don't miss anything. I'd be more worried about time-line antialiasing techniques, frankly. Audio techies will of course use 96 KHz 24-bit.

[khph_re]

Originally Posted by Photon

better or worse, but >= 28867 ensures you don't miss anything. I'd be more worried about time-line antialiasing techniques, frankly. Audio techies will of course use 96 KHz 24-bit.

So if i'm playing stuff that should be on a 56khz double scanned screen, at 14bit, will this rate cover it do you think? I've got a load of music i've converted to ADPCM and i'd like to test in UAE for quality before I put the CF back in the A1200.

[musojon74]

@Photon - aliasing not quantization noise. I will whip up a little demo proving that it needs to be nice and high (sudden edit - might be time to try on WinUAE again in case it is nicely oversampling everything and you can't hear what I'm worried about in it!) Unfiltered it will definitely show up playing high frequency synth sounds or whistly stuff. And yes 24 x 96 is always the way

[Photon]

khph_re: I don't understand the screen reference, but yes, >= 28867 in 16-bit covers up to 4 channels x 14-bit, and 28867x2 Hz=56KHz will handle un-interpolated (in emu) better. I can't answer about interpolation settings in emu because I don't know the algorithm used, but generally this requires the higher setting to not just be a "sound smoother". So that should be good.


musojon74: aliasing is the same phenomenon as quantization, just different axes.

The trick is comparing to how it sounds on a real Amiga (with the _Amiga_ filter set to whatever the original author of the sound intended, nothing else), so you're not being fooled by any post-processing in the emulator that makes it sound 'better' (remove some artifacts) and therefore making you think that's how it 'should' sound.

For example, plenty of early ST-xx samples or games have sound artifacts due to the quality of samplers then. Authors used audio filter on Amiga until it became non-standard about 1989-1990. Therefore they sound ok with filter and they sound as the author intended. Simply disabling filter in WinUAE is enough to scream "artifacts! I must change emulator settings / emu sucks!!" but this is not the case.

Compare to SID filter emulation for C64s with different filters.

It 'should' sound like the Amiga output, so any comparison should be made to an output from a real Amiga sampled at the same frequency as you use in the emulator. This is how to decide the accuracy of sample conversion, digital sampling oscilloscope on Amiga output vs recorded audio wave from emulator. Not by ear. If you are older than 30 years you can't trust your ears even if you are a studio musician, like you and me. A younger person with better ears would hear things we don't.

This is why I go by a minimum sampling frequency. This will only ensure that you don't miss anything.

If you use any postprocessing such as interpolation, you should only use a much higher frequency. If you don't, you should also use a much higher frequency.

[ancalimon]

We were desperate for 16bit sound and high frequencies when using our Amiga's 20 years ago and today we have it but want the lower sound quality back?

[daxb]

If you are older than 30 years you can't trust your ears even if you are a studio musician, like you and me. A younger person with better ears would hear things we don't.

In most cases this is true but "better ears" is independent (in most cases) from the age. In fact audibility can be equal with an age of 1-80. Industrialization is the problem with every day noise. E.g. old people living in the jungle can hear as good as they were young. However, that is off topic.

[LocalH]

As someone mentioned before, the issue is that the Amiga can independently output multiple sample rates. Let's say you have WinUAE outputting 28867Hz. Now what happens when the emulated Amiga outputs, oh, let's say a 9622Hz sample on channels 0 and 3, and a 19245Hz sample on channels 1 and 2. Good luck getting that 28867Hz output to sound anything like a real Amiga. And I made it slightly easier for you by using values 1/3 and 2/3 of 28867Hz. Now output a straight 8KHz sample on channel 2 and a 16KHz sample on channel 3. I think you'll find it impossible to output that mix at 28867Hz without interpolation while having it sound like the original.

My recommendation is the find the native sample rate of your soundcard, and set WinUAE to that rate.

[ancalimon]

would using asio4all have any advantage (latency and sound quality) when using WinUAE ?

http://asio4all.com/

[AmigaFriend]

Originally Posted by LocalH

My recommendation is the find the native sample rate of your soundcard, and set WinUAE to that rate.

Ditto. Do that and bother with nothing else.

Originally Posted by ancalimon

would using asio4all have any advantage (latency and sound quality) when using WinUAE ?

http://asio4all.com/

Yes in latency. Use PortAudio to select your ASIO driver. Remember that ASIO overrides any setting you've in Winuae audio panel.