Live Streaming Setup Update

How to setup live streaming using OBS, a video camera, and an XLR microphone.

Two posts ago, I talked about how I setup Open Broadcaster Software and my audio/video equipment to record and live stream events hosted by the Pride Alliance at my alma mater.

I have since upgraded a couple of things and wanted to share an update on how I do things now.

Hardware Setup

Video Camera

I use a Canon Vixia HF R400 video camera to record and live stream with. I setup this camera and record in camera in 1920 x 1080 px resolution with a medium quality so that my resulting files aren’t too big to upload to YouTube.

HDMI Capture Card Setup

I recently switched from using a TV Tuner Card (Hauppauge WinTV HVR-950Q) to a cheap HDMI capture card. When I ordered this capture card I wasn’t expecting much for $10, but it works perfectly fine for me and doesn’t get hot when I’m using it. Originally I bought it to mirror my camera to a larger display, but then I thought about using it for live streaming.

It is a Uoeos HDMI Capture Card that apparently isn’t available on Amazon anymore.

Audio Setup

I recently wanted some better quality audio in my recordings so I naturally asked my cousin who is a musician. He set me up with a USB audio interface and a couple of different microphones and a few XLR cables. Unfortunately the USB audio interface didn’t have a microphone level output that I felt comfortable plugging into my camera. I built a circuit to reduce the audio levels, however I wound up buying a device specifically made to connect an XLR microphone to a camera or smartphone.

XLR to camera Adapter

I needed a device to connect these XLR microphones to my camera which only has a 3.5mm mic jack. So I bought the Comica LinkFlex AD-2. It has a single XLR and 1/4″ Instrument combo jack and can supply 48v phantom power to power condenser microphones. In addition it can change it’s TRRS jack to work with a camera instead of a smartphone with the flip of a switch and it can output audio from the XLR or 1/4″ jack to a headphone jack so you can monitor the audio. Overall it works great for my needs and was priced just right. It’s a shame though that it only runs on a 9v battery. I wish it could be plugged into the wall. I was worried about the battery dying in the middle of the event, however, a fully charged 9v alkaline battery reads about 9.4V. After approximately 45 minutes of use the battery reads about 9.25v. That was with using the 48v phantom power too.

Microphones

At the last event I used an Audio Technica AT-2021 Condenser microphone that I had borrowed from my cousin. It has a cardioid pickup pattern and is more designed for recording instruments, however I found it worked very well (at least for me) for recording a person speaking.

I recently purchased a stereo matched pair of Behringer C-2 condenser microphones. These also have a cardioid pickup pattern. I haven’t had a chance to use them yet, but I’m thinking they will sound decent or maybe as good as the more expensive AT-2021. I’m a bad tester for that though with my low frequency hearing loss.

Plug for Sweetwater Music Store: This store was recommended to me by my uncle and I can’t say enough good things about the store. I made my order and they had a sales engineer (who has tons of experience and training in audio production and training on products) contact me by phone. I didn’t answer the phone because I didn’t recognize the number. The sales engineer left me a voicemail and sent me a text message to follow up with me about my order. He said he was always available if I had questions or just wanted to chat about anything audio or equipment. When I received my order I also got a Sweetwater logo sticker and a bag of a candy as a thanks for my order. This is a company that values their customers and will go above and beyond to help you out. They also pack their items extremely well. I’d give them 10 out of 5 stars if I could! I am not affiliated with them in any way; I’m just a very satisfied customer.

Cables

To connect the microphone to the camera interface, I’m just using a cheap MCSProAudio XLR Cable I found on Amazon. I bought a 50 foot cable thinking it would be long enough, but definitely should have bought a 100 foot cable. The 50 foot cable worked fine, I just had to connect another cable to it.

To connect the camera to the HDMI Capture Card I the HDMI cable that came with the camera.

Software Setup

OBS Setup & Settings

I use Open Broadcaster Software to stream to the student organization’s Facebook page.

I’m rescaling the output to 1280 x 720 px and sending it to Facebook with a Constant Bit Rate (CBR) of 2500 Kbps as seen below.

OBS Output Settings

In the video settings tab, I set the base canvas resolution to 1280 x 720 px as well as the output resolution and set the frame rate to 29.97 FPS as seen below.

OBS Video Settings

HDMI Capture Device Settings

In the “Sources” panel I have the resolution of the HDMI capture card set to 1280 x 720 px.

In the “Advanced Audio Properties” screen of the HDMI Capture Card’s settings (in the “Audio Mixer” panel) I have the HDMI capture card’s “Audio Monitoring” setting set to “Monitor AND Output”. This setting has caused me issues previously where I have forgotten to click the setting with output otherwise it won’t send audio to the live stream. I use this setting to monitor the audio I’m getting through the HDMI Capture Card.

I check the audio levels on the camera and adjust the Comica LinkFlex AD-2’s gain control to get the audio level right in the camera, then I adjust the audio level in OBS to get the right audio level output for the live stream. I typically monitor the audio level through OBS on my laptop so I know what the audio sounds like on the live stream.

Live Streaming & DIY Microphone

Backstory

During 6 and 1/2 of my 7 years of college (part time), I was President of and helped build a student organization for LGBTQ+ students and their allies. Every year we host an event comprised of speeches from students, faculty, and staff that I video tape. Eventually we began streaming the event live on Facebook. The event is always around the 2nd week of October.

Now I’m an alumni advisor to the organization and I’m still recording/live streaming the event. I wanted to post about how I do this, mainly for my future reference.

Recording/Live Streaming Setup

The event is held in a small, but beautiful chapel on campus. I normally setup the camera in the back corner of the room and the speaker is in the opposite corner in the front of the room. The recorded audio has always been decent, but it could definitely be better.

I connect the camera’s A/V output into the composite input cable on the TV Tuner, which is then plugged into the computer’s USB port. I use the software that came with the TV tuner or VirtualDub to set the channel on the TV tuner to the composite input. Then I can close VirtualDub or the TV tuner software and open OBS.

Computer Specs

OBS Setup

In OBS, I have a scene with just a photo source (the club’s logo). In another scene, I have the TV tuner’s video and audio sources. I run the photo a few minutes before we start and then switch over to the camera when the event begins. I do the actual recording in the camcorder at 1080p 30fps. Composite video has a standard resolution of 480i or 576i, so I set OBS to stream at a resolution of 640 x 480 to Facebook using a bit rate of 2000 kbps.

DIY Electret Condenser Microphones

Disclaimer

I am NOT responsible for any loss or damage resulting from the use or building of this project. PLEASE make sure your camera/device accepts this type of powered microphone before connecting it. I am NOT going to be responsible for any damage you may cause by building or using this microphone.

Parts list

  • 6 Feet of 2 Conductor Audio Cable – I used thin coax cable, RG-174.
  • 2 Mono 3.5mm (1/8″) Phone Plugs (male)
  • 2 Capacitors (100nF – Code 104) – I used the ceramic disc type.
  • 2 resistors (680 Ohm) – Value should match the impedance of the microphone elements you purchase.
  • 2 Microphone Elements – I used PUI Audio AUM-5047L-3-R.
  • 2 short lengths of PVC Pipe – I used 1/2″ Sched. 40 PVC cut at 6.5″.
  • 2 PVC End Caps – Size needs to match the PVC pipe.
  • Spray Paint
  • 1 Length of wood or PVC pipe cut at 26″
  • 2 Bolts – 6-32 size. Use a length that will go through 1/2″ PVC (OD = 0.84″) and your piece of wood/pipe. (I used 2.5″ bolts and they were a 1/2″ too long).
  • 8 Flat Washers – #6 Size
  • 2 Hex Nuts – 6-32 Size
  • 2 Wing Nuts – 6-32 Size
  • Heat Shrink Tubing (various sizes)
  • Air Conditioner Foam Filter
  • 3 Panel Mount 3.5mm Phone Jacks (female)
  • 9V Battery
  • 9V Battery Holder

Tools

  • Soldering Tools
    • 15W Soldering Iron
    • Solder – I used 63% Lead / 37% Tin with a rosin core.
    • Desoldering Wick
    • Flux Pen
  • Pliers
  • Wire Cutters
  • Wire Strippers
  • Tweezers (optional)
  • Lighter
  • Audacity Recording Software

I’m not going to go into painting the PVC and putting the bolts through it. Nor will I cover cutting the slots in the PVC pipe or the sewing of the windscreen foam.

How to Build The electronics

wiring the microphones & connectors

  1. The first thing I did was solder the connectors onto the ends of the coax or audio cable. Make sure you put the plug’s cover on first. I did not care about interoperability so I soldered the center conductor of the coax to the center pin and the shield of the coax to the sleeve of the connector. Put one connector on each 3 foot piece of cable.
  2. Put heat shrink over the cable first. (we’ll shrink this later).
  3. On the other end of the cable we’ll solder the microphone element to the wire. The center pin goes to the positive and the shield of the coax connects to the negative on the mic element. Try to do this quick and precisely or you’ll ruin the mic like I did on my first try. I had to order another one after ripping the solder pad off the mic element. The mic’s solder pads are tiny, about 1mm wide by 3mm long. Don’t short the two solder pads either.
  4. Slide the heat shrink tubing up enough to cover the wires a bit, but do NOT cover the back of the microphone element. Shrink it over the wire. Don’t over heat the wire or mic element.
  5. Make sure you’re soldering the center conductor to the positive solder pad on the mic element. I messed this up on one microphone and could not figure out why neither microphone worked with the circuit.
two microphones
Two completed microphones.

create the circuit

Mono Directional Electret Microphones – Power Supply & Mono to Stereo Connection Schematic

Using the above schematic, we’ll create the circuit used to power the microphones.

Basically, the resistors provide bias to the microphone elements. The value of these 2 resistors should match the impedance of the microphone elements you bought. Mine were 680 Ohm. These resistors should be 1/2 Watt resistors.

The capacitors block the battery’s direct current (DC) from getting into the camera. While capacitors block DC current, they allow AC current, such as an audio signal, to pass through.

NOTE: Some capacitors are polarized and must be installed with the positive leg facing the microphone elements. If you install the capacitor backwards you could damage your camera and/or the microphone elements. The capacitors used in this schematic are NOT polarized.

Project box with power switch.
Project box with power switch

Test for DC on the Output before use

Just to be on the safe side, I tested for any DC voltage on the output before I plugged this into my camera. Plug in the battery, turn the switch on and test the output connector with a multimeter for DC voltage to make sure there will NOT be any DC getting into the camera. If your multimeter detects DC voltage on the output do NOT plug it into the camera. Go back and check your connections.

Project box output side
Output Side of Project Box

Creating the Stereo Effect (Extremely Basic)

This part is a little over my head, but according to what I’ve read, you can create a stereo effect in one of many ways. Since I couldn’t find microphone elements with the correct polar patterns to create a single stereo microphone, I made two mono microphones that get connected to the circuit which connects both of them to the stereo mic input on my camera. By separating the microphones at least 24 inches using the piece of wood or pipe, you will get a “stereo” sound effect.

completed microphones showing spaced stereo positioning
Showing Spaced Stereo Positioning of Completed Microphones

Matching the microphones

Typically, when a stereo microphone is built, the two elements are “matched” to be sure that the sounds they record are the same volume and gain on both the left and right channels. This is done so that the volume of one channel is the same as the other, else the audio would not sound right.

I personally did NOT match my microphone elements. I am not recording professional audio and I needed something cheap. I also wasn’t 100% sure how to do it at home (it can be done fairly well at home though).

That said, the two microphones are from the same manufacturing lot, the audio sounds the same on both channels to me and the gain of each channel is extremely close when looked at with Audacity.

Results

The microphones sound MUCH better than the camera’s internal microphone. They’re fairly clear and provide decent audio for a “home” video. The volume of the recorded audio was almost exactly the same as the source audio I recorded.

The internal camera microphones sounded quieter than the source I was recording. While they were clear, the audio didn’t sound as clear or as full as the microphones I built. The audio from the camera sounded like it was too deep.

Sources

I used many sources and forums to find the information necessary to build my microphones. I originally was trying to build a shotgun microphone (a very directional microphone employing an interference tube design), but there was significantly more information on building a DIY Directional Microphone, so I went with that. I did research over the course of a couple of weeks trying to learn enough to build this project. The circuit is the basic manufacturer’s recommended design for a single microphone element that has been modified to connect two microphone elements to the same battery and stereo output connector.

I want to thank everyone who put this information out there for others to use.