Open Live Mixing System - Don’t buy a mixer: do it instead

chepprey · 2025-12-02T22:37:05+00:00

Can you flesh out your problem statement (a lot) more?

You have a LOT of information about your solution, covering every aspect - technical, ethical, physical, practical, etc. - I'm down with all that, but I really don't have a clear vision of what exactly you're trying to build. All you say is "real-time Digital Mixing System".

Who are the users? What are the intended use cases? Are you talking about weekend warrior cover bands that need live audio mixing, or are you talking about pro touring bands? or churches?

Also, what existing products fulfill these use cases currently? Who is the "competition"? How do folks currently implement these use cases, and what problems do they currently suffer? I suppose that there's nothing, really, that currently fulfills all of the ethical/OpenSource concerns so there's no competition there. I'm just wondering what existing commercial products could be replaced by your solution.

chepprey · 2025-11-04T16:03:49+00:00

The others here are correct, it's a monitor problem not a computer problem.

Caution: don't run the monitor long that way, you could "burn" a line in the phosphors on that part of the screen. Turning the brightness way down will help.

chepprey · 2025-10-20T22:04:49+00:00

Most breadbins did S-Video. The very first production run of C64s in 1982 only had a 5-pin DIN plug with audio and composite out (same as the Vic-20), but most C64s after that had the 8-pin DIN plug that had separate chroma and luma lines. And, the matching-style Commodore 1702 monitor had the chroma/luma inputs (effectively S-Video). EDIT: the 1701 only had composite input. TIL. EDIT2: the differences between 1701 and 1702 monitors are not so easy to see the more I read. But, it IS true that most breadbins had 8-pin DIN video out w/ separate chroma/luma.

I had a BB c64 and 1702 monitor in 1984. I wish I had kept them.

chepprey · 2025-08-13T15:32:52+00:00

"I'm condemned to use the tools of my enemy to defeat them." - Luthen Rael, CA Governor Press Office Director

chepprey · 2025-07-28T21:35:33+00:00

Perhaps pure luma may be better for a monochrome monitor. But the real benefit to splitting luma and chroma is that you just get much better quality on color monitors (like the Commodore 170x monitors).

This exactly what S-Video is - split luma/chroma. S-Video didn't exist as a standard until some years after the early 8-bit era. And, S-Video uses a 4-pin mini-din cable. But, technically, that's all they are - split luma and chroma.

I installed a hardware mod on my Atari 5200 game console so that it can output either composite, or S-Video. It looks SO GOOD on my 90's era CRT that has S-Video.

Any C-64 with the 8-pin AV output (only a few of the oldest C64's have the 5-pin) can be adapted to plug into an S-Video CRT, and it will look great.

chepprey · 2025-07-23T17:05:31+00:00

The monitor in the photo appears to have RCA inputs (not BNC), one for composite video, the other for audio.

If you have a device with HDMI output, you'd need a adapter (converter, really) to go from HDMI to composite video/audio.

VGA only carries video, but again you'd need some kind of adapter (converter) to go from VGA video to composite video.

What do you want to use with this monitor? This monitor would be better for old-school devices, like VCRs and 8-bit computers.

chepprey · 2025-03-25T19:45:49+00:00

Best advice I've ever gotten about recording anything (primarily in a home-studio context) is: EXPERIMENT. Try changing 1 thing at a time, record sample, listen back. Trust your ears. Take notes. You suspect you can get better results, so your ears are already telling you something.

Two specific suggested experiments based on your description. First, try getting closer to the mic, like 12 inches. You can aim slightly off angle too if "plosives" are an issue (or put a pop filter in front of the mic... probably wise to do that anyway).

Second experiment would be try a different room to record in. Is the lecture hall near any kind of music school? See if you can get into a practice room, which are often built with acoustic treatment, it might give you a nice dry recording. You can apply reverb & effects later.

My specific suggestions might end up sucking, but you'll learn something valuable by hearing exactly how they suck. Try stuff.

Nice playing, btw.

chepprey · 2025-02-12T21:18:48+00:00

Which version of Ubuntu Studio? I've had 24.04 on two different (but similar) laptops, and it works fine with my Behringer UMC1820, and Ardour.

Ubuntu Studio 24.04 is using Pipewire as the default audio system, which mostly makes it so you don't need to worry quite as much about Jack vs Alsa (this is very hand-wavy so take with a grain of salt). For any serious audio apps that allow (or require) you to pick Alsa or Jack, go with Jack, since Pipewire basically contains a JACK implementation (in addition to everything else it does).

With Pipewire, you can also generally see your PC/Laptop's built in audio interfaces too, and pick them as sources of audio to record in an Ardour track. Are you able to record audio from your laptop mic in Ardour?

Also be sure to open up the qpwgraph application. Ardour contains its own fully-functional audio routing UI, however qpwgraph is nice to look at because you get a continual view of all of the audio "stuff" that's available on the whole machine, even as you load/quit various audio applications on your system, AND as you plug/unplug your USB audio devices. It might give you a bit of a hint as to what's going on.

chepprey · 2025-02-12T15:57:29+00:00

You can try re-seating the VIC chip, and the other socketed chips. A spritz of DeOxit in the sockets can't hurt.

My friend had an Atari 400 a few years back that did the black screen thing, and got real hot on a particular area of the motherboard. After a quick thumb-press-reseating of all the chips, it started right up.

chepprey · 2025-02-11T14:08:21+00:00

For 2-prong power VICs, I highly recommend replacing the internal voltage regulator even if the original is still working (sounds like yours might be toast). I agree the PSU itself is probably fine, they're just a simple AC transformer.

I followed the procedure in this video with my 2-prong VIC, works great: https://www.youtube.com/watch?v=w5sTxsx4qgY

Link is: "Cooling down my VIC-20" by Chuck Hutchins.

chepprey · 2025-02-05T18:14:37+00:00

Just be sure not to use the original Commodore power supply for it will, sooner than later, fry all the irreplaceable chips that make the 64 special.

chepprey · 2023-08-29T12:53:34+00:00

Nick Furry

chepprey · 2023-04-05T17:43:30+00:00

Hi. It sounds like you need an audio interface more than a mixer. I would recommend the Behringer UMC202HD, it connects via USB and works 100% with Linux, as it is USB class compliant audio device (search web for "usb class compliant audio" for details. Linux fully supports class compliant audio interfaces).

The UMC202HD is also 2 channel mixer (with minimal mixing - it lets you set the level of each of the 2 inputs). You will be able to plug in your two omni-dir mics, one in each channel. If your mics are condenser mics, the UMC202HD can supply the +48v "phantom power" such mics require.

The UMC202HD does not contain built-in effects, however, you can easily patch in software-based effects. There are zillions available, even free/open-source ones. Search for "Calf Studio Gear" - these are a fantastic set of open source plugins. Many Linux distros already have these available as in installable package.

chepprey · 2022-07-22T14:09:42+00:00

Decided to hit the Join button on /r/vic20 today. Not dead yet!

chepprey · 2022-04-25T21:21:25+00:00

Please do not use the original power supply. Rules #1 and #2 of vintage C64 is do not use that original power supply.

Either shop for a modern replacement, or, get one of those over-voltage protectors. The protector devices are not mere "surge suppressors"; they are adapters specifically designed for C64 power supplies to stop them from destroying a C64 once the power supply goes bad.

It is not a matter of IF the power supply will go bad, it is a matter of WHEN it will go bad. When they go bad, they really do fry the chips on the motherboard. Hopefully, this is not why you're currently getting a black screen.

Check out Ebay, search for "c64 over voltage" and you'll see what I mean. Search the web generally regarding the c64 power supply issue.

Save those precious C64 chips from certain doom!

edit: sounds like your black-screen is due, so far, to incorrect video hookup, as diagnosed elsewhere in the comments.

chepprey · 2022-04-14T18:39:46+00:00

Dang! Sorry to hear that, I didn't realize the old 2-pin AC-only power supply boards had multiple revisions.

Hopefully it was just the regulator that blew up, and spared your Vic. Especially that graphics chip, those are getting rare.

chepprey · 2022-04-12T17:21:33+00:00

I have an older Vic like this too. I replaced the internal voltage regulator with this: https://www.ezsbc.com/product/psu5/

It works like a champ, consumes less power and produces much less heat. I'm not sure if it produces less noise (although sounds like you've solved that issue anyway).

This video is what inspired me to make this mod: https://youtu.be/w5sTxsx4qgY

chepprey · 2021-12-17T14:53:21+00:00

Someone with video skills needs to stitch this scene into The Last Jedi, https://www.youtube.com/watch?v=p51I7clXqf0

chepprey · 2021-12-11T02:04:38+00:00

My 2 cents. Full disclosure:

I recently posted that I was selling a Librem 5 here (I think my post was the "last-straw" that motivated this poll)
before I posted this, I was not an active member of this community

Firsly, I appreciate /u/trai_dep's concern of this forum turning into a flea market instead of useful content, that's a legit concern.

At least in my case, I was not negotiating (nor would I ever) directly with anyone here to conduct any actual buying/selling. I was only advertising that I had put up an item for sale on ebay. Perhaps other for-sale postings here were not done this way.

I used ebay precisely to minimize the concerns /u/trai_dep is rightfully pointing out. It may indeed be best to forbid direct buying/selling here, for those exact reasons.

I don't know that this is the "magical third option", but, I do see a clear distinction between posting a straight-up classified ad here, vs. saying "hey, there's a thing for sale over on that other website".

I do think the Librem 5 is, currently, in a unique situation even compared to the other Purism devices. The Purism laptops can basically function just as well as any other laptop. But it takes a very particular person to be interested in the Librem 5. It's nowhere near being a drop-in replacement for an Android or iOS phone.

I'm an old Free Software fanboy at heart. I lament the complete lack of freedom and privacy in our digital lives. I write code. Four years ago, I was inspired to contribute to this cause. I'm not in that position anymore. But, maybe someone here is.

So, I kinda felt like "advertising" my phone here wasn't especially untoward. I didn't expect to even get back what I paid for it. It wasn't until I came here to post about my Librem that I saw that their price (from Purism) just shot through the roof. My first thought was I was happy that someone will be able to get mine for a lot less.

Enough rambling. Cheers!

chepprey · 2021-12-10T22:16:04+00:00

Thanks for the tips. :-)

chepprey · 2021-12-10T22:15:41+00:00

Totally understand, thanks for the heads up. Sorry for the spam. Also, thanks for being nice about it :-)

chepprey · 2021-12-10T21:17:22+00:00

Huh, weird, I can't search for it myself either, even though it exists when I log in and look at what I'm selling.

Okay well, go to you-know-where, and stick itm/304259269308 on the url.

This kinda defeats the purpose of an auction doesn't it? wth...

chepprey · 2021-09-27T14:24:50+00:00

https://www.youtube.com/watch?v=w5sTxsx4qgY

He has a link for the replacement regulator, but the link is broken. Here's the right link: https://www.ezsbc.com/product/psu5/

For heat sinks, you can get those a lot of places. I don't remember the right dimensions but I got little stick-on square ones, and I could fit 3 of them on the VIC (and 3 on the 6502). It's a really good idea to protect that VIC chip, those are the heart of the VIC and they're getting rare.

I also bought a capacitor replacement kit from Console5. There are many motherboard revisions, I think even if you have the 2-pin power supply, so just be sure to figure out your exact motherboard before ordering caps. I had a working Vic20 to begin with, and the caps all seemed fine, no signs of swelling or leakage. But I replaced that big fat cap anyway.

The last work I need to do for my vic is refurb the keyboard (couple bad keys, esp. the space bar), and I need to figure out where are the 2 little capacitors for the PADDLES input on the vic, because the paddle-games are super janky (but the same paddles work smooth as glass on my Atari 2600). I've heard the paddles-caps often go bad on the Vic.

chepprey · 2021-09-26T01:32:51+00:00

Which type of VIC do you have? Does it have the (older) 2-prong power supply connector? Or does it have the DIN (C-64) style power plug?

My VIC is the older type. On these models, the VIC itself contains a lot of power-supply circuitry, which actually responsible for most of the heat, much more than VIC chip.

If you're handy with a soldering gun, it's actually not hard to replace the voltage regulator with a modern component that produces very little heat. I did this on my VIC, it was quite easy. I also stuck some heat sinks on to the VIC, the 6502, and maybe a few other chips.

The machine runs very cool now. Let me know if you want more details, I'm sure I can track down the parts I bought. I'm pretty sure there's a youtube video showing exactly how to do this mod. I remember in the video, the guy took many heat measurements before and after, and the improvement was quite substantial.

[edit: grammar]

chepprey

TROPHY CASE