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Mac Start Sound on PC?

LC_575

Well-known member
I have always wanted an actual WAV quality sound to be the POST beep, just like on any Mac. But is it possible, at all?

I guess it would require some kind of custom BIOS using a built-in sound chip on the logic board. I doubt it could be actually implemented in place of the POST beep, but then again I have seen some rather advanced BIOSes, such as those on Asus boards like mine. If not during the POST, then perhaps as part of the OS bootup. I couldn't see Windows doing it, but perhaps in some mod for Linux.

 

MacJunky

Well-known member
My ASUS G2S-A1, instead of a beep plays an explosion sound+animation. One would need to manually edit that section of the BIOS though.

The easiest way imo is to just change the windows login sound I guess. I dunno about XP, but in Win7 it is C:/Windows/Media/Windows Logon Sound.wav

 

Dennis Nedry

Well-known member
Conceptually, that's WAY easy of a thing to do if you're up to a little digital design. Here's how:

Grab a parallel ROM chip, burn it with the raw Mac sound. Hook the data outputs of the ROM straight up to the inputs of an DAC chip. Tap the DAC outputs (i.e. analog audio) to your sound card. Garb a timer and/or crystal and have yourself an 11.025 kHz wave. Run that into the clock of a counter. (you may need multiple counters) Hook the counter outputs to the address inputs of the ROM. Lastly, add some simple logic to ensure starting at address 0 and to stop counting at the end of the ROM. Extra credit to play the sound backwards after shutdown.

It's more of a project for geeks with breadboards and tinkering; don't expect to follow this advice for a quick and easy solution!

 

MacJunky

Well-known member
Get one of those stupid "yakbak" things from the 90s that kids used to play with, record the desired chime then mount in the case and it's play button (relocated) poking through the case. Press chime button after hitting the power button and there is your chime!

hahahahaha

 

Dennis Nedry

Well-known member
You could put a little Mac LC-style logic board inside your PC and power it off of the PC's power supply. The 5500 is common and has a pretty small board if you need the PPC sound. Rudimentary but effective.

 

LC_575

Well-known member
I'm wondering now if we could make these ideas into an actual tutorial for the wiki.

 

techknight

Well-known member
not sure how big the actual size of the RAW chime sound is.

But, you could probably fit it inside the ATmega128 CPU and it has an on-board PWM which should be sufficient enough to work as an 8-bit DAC. even though the PWM is capable of 16 bits using the whole timer.

then you can setup another timer register in your code as your sample rate, append the raw data at the bottom of your code and then have the code read in the RAW data, output the PWM. use an R/C filter on the output of the PWM of the AVR, use an LM386 style audio amplifier, bingo, instant chime.

The output of the LM386 could be capacitor-coupled to the green audio output jack of the system board. And you can have the code set to chime on power-up and have another wire hooked to the system RESET pulse on the PCI bus.

So when you power up your computer, the AVR circuits power, and chimes through your speakers.

if you restart the computer or hit the reset button, the PCI bus will do a master RESET, and your code is setup to see the pulse, you will get another chime

done...

 

protocol7

Well-known member
The startup chime is about 30k (looking at the copy Basillisk II extracted here). 8-bit, 22.5kHz, mono. You can also extract it from a ROM file using Audacity:

Set the project sample rate to 22050Hz

Import the ROM as raw data (unsigned 8-bit PCM, Big-Endian, Mono, 22050Hz)

You'll see the chime near the end of the file.

Crop away all the other data and save the file out.

 

LC_575

Well-known member
What about implementing the sound via after-the-bios software, such as a bootloader?

 

techknight

Well-known member
I dont know, its just a random idea I came up with.

But its feasable with a little time and effort. The Hackintosh SE project i was going to do that never materialized, I was going to implement this.

using a Micro-ITX motherboard, a CRT VGA board using its original CRT, i was going to use an ADB to USB adapter so i could still use the original keyboard and mouse.

Then i was going to wire that circuit up as the chime sounder.

 
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