The SC-55 has a line-in. Connect the MT-32 to the SC-55 then to the sound card.

Also the USB cables you show probably only work to digitize sound but not to echo it back to your speakers. Finally, you'll be adding needless CPU overhead since USB is far from efficient as it requires cpu polling.

When using the MT-32, just press 'ALL' and then 'MUTE'. This will silence the SC-55 part, and let the MT-32 pass thru.

Wait, are you saying that your port on your PC double as a mic and line in?
Maybe try and see if you can force the port to have zero gain.

SierraGamer wrote:

without having to use an external mixer

Just curious, but is there any particular reason you're avoiding an external mixer? Because of all the options, it seems the most straightforward as far as a "set it and forget it" type of setup.

tpowell.ca wrote:

Also the USB cables you show probably only work to digitize sound but not to echo it back to your speakers. Finally, you'll be adding needless CPU overhead since USB is far from efficient as it requires cpu polling.

Thanks, very good to know. Looks like I'll have to scratch off the idea of getting those USB cables.

tpowell.ca wrote:

Wait, are you saying that your port on your PC double as a mic and line in?
Maybe try and see if you can force the port to have zero gain.

Yep, that's right, the port doubles as a mic and line-in. [SEE PIC ATTACHMENT SHOWING PORT COLORED HALF IN PINK AND HALF IN BLUE] I would love to be able to just use that port, and I have driven myself crazy trying to get it to work. How do you force the port to have zero gain?

I have set up a few computers with MT-32 units for family members, and each time I've avoided using computers with those combo ports. Unfortunately, many cheaper, small form factor computers have those combo mic+line-in ports.

Shponglefan wrote:

SierraGamer wrote:

without having to use an external mixer

Just curious, but is there any particular reason you're avoiding an external mixer? Because of all the options, it seems the most straightforward as far as a "set it and forget it" type of setup.

I have a mixer that I like very much. But here's how I (perhaps under false assumptions) arrived at thinking I could get by just as easily without a mixer:

My line-in+mic combo port was leading to distorted sound. So I bought a Sound Blaster Audigy Fx PCIe card in order to get the separate line-in port. But my computer didn't recognize the sound card, and Creative Labs tech support said, after I tried all their other suggestions, that I should switch PCI slots. Unfortunately, I didn't have any other slots available. So I returned the Sound Blaster card and thought I should look into an external sound card in order to get a separate line-in port. It was then that I learned about those USB line-in converters that I linked to in my original post. Right now I have both Roland modules connected to an external Behringer mixer, which has worked great when I was using another computer, but I thought that I would be able to just connect both modules separately to USB ports on my computer, thus freeing up desk space, as I imagined I wouldn't need a mixer, if that set-up were to work. But, after reading the first response in this thread, now I'm thinking those USB converters wouldn't even work.

So, bottom line, I'm perfectly fine using a mixer, if I have to (since I do like not having to re-plug and unplug after the initial set-up), but if it were possible to get by with less hardware on my desk, I would be interested in looking into such an option. However, if the choice were having to have another piece of hardware on my desk, on one hand, and having to adjust cables over and over, I'd happily go with needing an additional piece of hardware on my desk.

Anyway, even with the mixer, I'll still have to contend with the weird combo mic+line-in port issue on this computer. I am going to try the "zero gain" idea, mentioned earlier in the thread, when I get home later. If that doesn't work, maybe I'll have to get an external sound card?

Sorry for the long response. Just wanted to explain things as clearly as I could.

I really do appreciate your help.

You also do NOT need two separate usb midi interfaces either. Use the midi thru on the SC-55 and plug it into the midi in on the MT-32. Yes the SC-55 will also receive the same midi messages that you want to the MT-32 but it will still pass them through. That is how I have my MT-200 with my MT-32 setup. I then have both of their outputs going into a simple AV switcher with the audio out going back into the line-in on my sound card.My sound card also has a combo mic/line-in, but in the sound card software I have to specify if I'm using it for Mic input or line-in and I never use a mic so line in it is. But you really don't need all that hardware to connect these two up together when one USB Midi interface will do the job.

CrossBow777 wrote:

My sound card also has a combo mic/line-in, but in the sound card software I have to specify if I'm using it for Mic input or line-in and I never use a mic so line in it is..

Yep, having the option to select "Line In" and not just "Microphone" is exactly what I need. I can't figure out how to do that with on-board audio (no separate sound card) on my Dell Optiplex running Windows 7. And you make a good point about needing just the one interface.

Would something like this external sound card linked below allow me to bypass the line-in/mic combination port issue and get the "Line In" option to select and not just "Microphone"?:
https://www.walmart.com/ip/Startech-7-1-USB-A … -Audio/14291558

I could run an audio cable from the "main out" on my mixer to the "line-in" on that external card linked directly above, no?

UPDATE:
- Distortion is only an issue with the MT-32 music, and it's pretty bad. Sounds very screechy with static. The SC-55 music doesn't seem to have any distortion. This is on a Dell Optiplex 7010.
- I tested out the MT-32 on another computer I have, and the MT-32 sounded fine without any distortion that I could hear.
***** Note that this other computer, a Lenovo, has a separate line-in port and shows a "line-in" device option in the "Recording" tab in the Windows 7 sound settings window. The Dell Optiplex 7010 that I need to set up the MT-32 on has the combination mic/line-in port and only shows two "Microphone" devices in the same "Recording" tab, even when I select "show disabled devices" and when I have the audio jack plugged in. In "properties" for the selected device (which is "Microphone" on the Dell and "Line-In" on the Lenovo), I check the box next to "listen to this device" in the "Listen" tab. I think it's interesting that the MT-32 sounds very distorted when "Microphone" is selected, but the SC-55 seems to handle it fine. And both work on the Lenovo (a computer I won't have much longer), which has "Line-In" as a listed device option that I can mark as "default device" in the "Recording" tab. Again, the Dell, which has the combo mic/line-in port, lists only "Microphone" on the "Recording" tab.
- Also, I have a second Dell Optiplex 7010 computer, and the MT-32 was also distorted on that one, with the same settings, while the SC-55 sounded fine.
- I'm testing out the music using various Sierra games through DosBox.

My conclusion: the problem is not that I have a defective MT-32 or defective audio or MIDI cables. My guess is that my MT-32 is not doing anything differently than what other first gen MT-32 units would do under similar circumstances. The problem seems to be that the MT-32 doesn't work properly when I'm having to select "Microphone" instead of "Line In" as the default recording device. It's interesting that the SC-55 seems to work fine both ways.

P.S.- is it normal for the MT-32 power adapter to get very warm? I'm using a cheap generic adapter that was advertised for the MT-32 and listed these specs: Input -- 100-240V, Output -- 1A(Fit current 1000mA and below).

LATEST UPDATE: SUCCESS!!! The problem was that I needed to update my Dell computer drivers for my computer model for Realtek HD Audio. Now I'm able to select whether I want to use "line in" or "mic" in the combo port. Apparently a Windows update had messed things up around 2016, so if any of you out there have a Dell and are having this problem, then visit the Dell website and get your latest Audio or Realtek audio drivers for your model.