Getting JackTrip Virtual Studio devices working

[Dan Lyke]

Hi! I'm a Jamulus user, but my voice teacher has had trouble keeping her Jamulus client configuration stable, so I bought a pair of JackTrip Virtual Studio devices, and now I'm trying to get those working.

First problem was that I got my mic cables from Sweetwater shipped USPS, and a week later they're still "in transit". But I'm hoping to be able to drop a device on my voice teacher's door step tomorrow, and would really love to get these things working. So, I'm trying to get things working with what I've got. With that, three questions:

1. I have the JackTrip Virtual Studio device plugged in. I logged in with jacktrip.local, created an account, saw the device. I created a server, connected to the server, and am getting nothing, with several different microphones and headphones.

Headphones are plugged into the RCA jacks via an RCA to 1/8" female adapter cable.

Microphones have been plugged into the 1/8" jack above the power connection (there's also a 1/8" jack to the right of the power connection, past the two... I dunno, mini HDMI? ... connections, I've been assuming this is the Pi audio jack and ignoring it).

I have tried 3 microphones:
* Random computer conferencing mic with a mono 1/8" jack.
* Cheap Logitech headset with separate mono mic & stereo headphone jacks.
* Sennheiser e935 mic + Monoprice XQ-16-MF-06 XLR to mono 1/4TS cable+RadioShack 1/4" stereo female to 1/8" stereo male cable.

A few times I've gotten it into a state I can hear noise in the headphones when plugging and unplugging the mic cables, so I *think* I've got the correct connections, and I don't know whether the Monoprice cable is balanced or unbalanced, though the TS jack is mono so I think that means unbalanced.

If I turn all the volume to max and the reverb up high, should I be hearing some sort of monitor? Is there a way that I can test the headphones side of things? Am I totally barking up the wrong tree and should just wait for the Sweetwater cables?

2. I see mention of Jamulus servers. I would *love* to be able to configure these devices so that when you plug them in they just connect to my (home, Sonic Fiber, on an Ubuntu box) Jamulus server, so that my voice teacher has to do nothing but flip the switch on 5 minutes before our lessons (and I don't have to admin more software). Putting an IP address in the server connection box doesn't seem to let me connect. Is there an easy way to connect to a Jamulus server?

3. If I configure one of these devices and hand it to my voice teacher, will I see it as part of my devices, or, because it's on her network, will she have to log in and admin it?

4. Okay, a fourth question: I have cables I can cut apart. I have a soldering iron. Anyone have a favorite wiring diagram and I'll solder something up?

Thank you for any insight you can offer...

Dan

[Wm Leler]

1. The 1/8 inch mic jack (to the left of the two RCA jacks) is stereo unbalanced TRS (and not balanced). Unfortunately, the Monoprice mic cable is balanced, so it won't work. That is one problem. Also, make sure you are not using any condenser microphones, as the VS box does not supply bias voltage. Your Sennheiser e935 is a dynamic mic, so it should work (with the right cable). If plugging and unplugging the mic makes noise come out of the headphones, the mic or its cable are definitely the problem.

2. As for your server question, you have to set up an unmanaged server. This is just a front end to your own server. See https://help.jacktrip.org/hc/en-us/articles/360056926013-Creating-Unmanaged-Servers

3. To manage a device, it must be on the same local area network (LAN). You cannot control a remote device. If you have registered your voice teacher's device, you will have to unregister it, and give it to her, and she will have to register it and manage it.

4. I tried soldering up my own mic cable, and it caused a ground loop. Now that the snowpocalypse is over, hopefully you will get the cable you ordered soon.

good luck!

--wm

[neal rhodes]

I agree/disagree with master Leler.  The VS box as delivered does not supply bias voltage.  Set jumper pins J1 and J3, and turn on bias voltage with amixer and it certainly WILL supply bias voltage and run any common PC desktop mic which wants 2.5V bias to run.  There are some nice/cheap mics which work very well.  All 10 of our boxes in use have desktop PC mics. 

Also, note that the Jambox boot image CAN work with HiFiBerry with a little dinking, and it does seem to set the bias  voltage on.

regards,

Neal

[Wm Leler]

Neal is correct that the VS box CAN be modified to supply bias voltage, but it requires both a hardware and a software change.

Neal, now that the VS software is open sourced, we would love it if you would submit a pull request to turn on the bias voltage. If you do that, I'll talk them into installing the jumpers.

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[neal rhodes]

Master, you speak in riddles...

Not clear on pull request.   What that means.  The necessary software command is:

/usr/bin/amixer set 'ADC Mic Bias',0 'Mic Bias on' 

I'm pretty sure this can be done for all hifiberry;  without jumpers I don't think you get voltage even with the command.

What seems slightly weird to me is that all the USB adapters I have tried already have this voltage set.  Only HiFiBerry does not.

Note that I have not tried this with the latest boot.   Our recent builds have been USB.

I never did decipher the startup process, so I just stuck that command in a shell script, and invoked it from rc.local.   eg:

mount -o remount,rw /
cd /usr/local/bin
vi biasOn.sh

echo "Starting biasOn.sh script...."
sleep 15
echo "Turning on Bias Voltage on Mic; Set Jumpers J1, J3"
/usr/bin/amixer set 'ADC Mic Bias',0 'Mic Bias on'

chmod a+x biasOn.sh
cd /etc
vi rc.local

add: /usr/local/bin/biasOn.sh &

sync
reboot

Not too bad if you have the device in your hands, but a real booger if your singer bought one and lives 200 miles away.

regards,

Neal

[Newport Dances]

I'll chime in on one point of the mic cables.

The Hosa cables in the Sweetwater configuration are pretty much worthless. In 8 mics tested with 4 cables and 4 JT boxes, none of them could deliver enough volume unless singing loudly with lips directly over the mic.  The JS site came up with a new recommendation of Cable Matters from Amazon.  Their 6' cable is $9.99 is a really nice cable!  This change of cable roughly increased the volume delivered to the box by 4X.  In practical terms, I can sing at moderate volume 18" away from the mic and be equal to the volume of singing loudly lips-on.

https://www.amazon.com/gp/product/B00ZIY06CA/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

Best,

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[JS]

This is only an issue if the Hifiberry board is not the "pro" version of the "DAC+ ADC". If the VS device is intended for use with vocalists, I'd suggest building your own with the Hifiberry "DAC+ ADC pro" (https://help.jacktrip.org/hc/en-us/articles/360055205193-Recommended-Build-HiFiBerry-ADC-DAC-Pro) which provides built-in mic gain adjustment via software. app.jacktrip.org would also recognize that it's a "Pro" device and would provide a slider for adjusting the gain on the device.

[Dan Lyke]

Just wanted to acknowledge a huge thank-you to everyone who answered my questions on this thread. The answer seems to be "wait for my cables to arrive from Sweetwater and hope I get lucky with them" (pout), especially since we just dropped Prime, so the Amazon cables would cost me extra for shipping.

Dan

[Dan Lyke]

Further follow-up: Hosa cables arrived from Sweetwater, everything appears to work although, yeah, a little mic preamp probably wouldn't be a bad thing, but I'll deliver this to my voice teacher and hopefully it'll all just plug-and-play, and when we can rent servers I'll do that rather than trying to run one myself because at this point it's easier to let someone else deal with admin. Thanks, y'all!

[Elizabeth Brown]

Just a quick comment, once you've registered both devices it is absolutely possible to remotely connect your registered devices using virtual studio - I have tested this successfully, and it really simplifies things if you are dealing with multiple musicians - all they have to do is plug everything in and power the box, then you connect the devices using the Virtual Studio app.

As a side note, if a server is public on Virtual studio and you connect to it using the command line instead of a jacktrip box, you absolutely connect correctly, but the server owner cannot see you on the server page. stealth mode! haha.