• Please review our updated Terms and Rules here

Tandy Sound Compatible PCB

Allright ignore that complaint about hissing.


It's not even noticeable during normal usage. Maybe I had the PC speaker volume turned up too much or something at that point...
 
Last edited:
That sounds great! You gotta do Space Quest 1! You can force Tandy audio by adding -t as argument
 
The PC-speaker OUTPUT header doesn't seem to be doing anything, or my pc speaker is broken.

The kids are all in the basement watching movies so I doubt I'll get much of a chance to get clean recordings for the rest of the night.

*edit* I didn't use the right kind of PC speaker output component. Mine only has three connectors, not the five the auto-switch would need.

I jumpered the audio line directly to the pc speaker audio pin and it works with pc speaker.

Also, Space Quest I started up in EGA mode and played music through the Tandy board with no problems. I'll try to get some recordings.

*/edit*
 
Last edited:
OK, I told the kids to pause the movie and made them suffer through two minutes of state-of-the-art 1986 audio glory.

Here you go, CarlosTex:

 
The squeal is from the PC speaker. If I turn it up enough to be audible during boot, there's a tremendous amount of high-frequency noise.

Would a ferrite bead filter that? It looks like most of my soundcards with a PC-speaker input have a FB on the audio input line, and aren't those supposed to filter EMI interference?
 
They provide low pass filtering basically. Are you able to measure the frequency?
 
keenerb said:
OK, I told the kids to pause the movie and made them suffer through two minutes of state-of-the-art 1986 audio glory.

Here you go, CarlosTex:

Click to expand...

Thank you for that!! Sounds awesome!

Hope your kids weren't too bored by the 2 mins of ancient 3 voice square wave tones!
 
keenerb said:
Allright ignore that complaint about hissing.

It's not even noticeable during normal usage. Maybe I had the PC speaker volume turned up too much or something at that point...
Click to expand...

Sounds great!
By the way, if you didn't recognize the tune, it's from INTROjr, the first and only demoscene production on PCjr, by Hornet (Trixter and Phoenix basically). Here it is captured directly from a real PCjr:
 
Trixter said:
This is why there can be is no generic solution, and patching each game (ugh) is the only way to go. Sounds like someone needs to create a Tandy-audio-force-patched archive.



There are an extremely small number of games that support 3-voice only *and* cannot be individually selected in a setup program *and* aren't AGI games which can redirect 3-voice to something else. The audience for such a configuration would be limited.



The method in question is V8086 mode, and if you're going to go through all that trouble, you might as well write a Tandy 1000 emulator so that you can intercept the graphics as well (which is almost exactly what Tand-Em is).



That is way more difficult than patching autodetection, because the existing code looks like this:

Code: 
E6C0              OUT     C0,AL

...but you want to change it to this:

Code: 
52                PUSH    DX
BAE001            MOV     DX,01E0
EE                OUT     DX,AL
5A                POP     DX

If there's no room to space-optimize near the patch, you're in trouble.

I really don't think this board is practical to support in >8086.
Click to expand...

Is there an alternate address less than FF that would be easier to patch into game code and is free on AT-class systems?

E0 - E7?

We're supporting 1E0 but game support at that address is negligible enough to discount anyway, isn't it?

Maybe a non-standard port would be better.

http://bitsavers.trailing-edge.com/pdf/ibm/pc/at/1502494_PC_AT_Technical_Reference_Mar84.pdf says that E0 is free on at least that particular 286 system.

https://www.manualslib.com/manual/161795/Sony-486dx.html?page=11 says the same.
 
Last edited:
I think adding support for an unused, atypical, nonstandard port is against the spirit of the project. At that point you're making a custom piece of homebrew for just you, as opposed to something that can be utilized by hundreds of existing software titles. If my vote matters, I would be against changing the design to add this.
 
Trixter said:
I think adding support for an unused, atypical, nonstandard port is against the spirit of the project. At that point you're making a custom piece of homebrew for just you, as opposed to something that can be utilized by hundreds of existing software titles. If my vote matters, I would be against changing the design to add this.
Click to expand...

It's not opposed to, it's complementary to, isn't it? I think the spirit of the project is perfectly intact by virtue of the C0 default port.
 
Last edited:
You must log in or register to reply here.
Back
Top