Tuesday, 3 January 2017

'LIVE' recording from Mixer

 Recording From Mixer?

In church, some always talk about budget in recording. As well as the church I attend. In recording, we emphasized on a few important key points:


  1. Low noise
  2. Strong signal
  3. Small size and high quality softcopy. 

Recommendation? There are so many in the market. Some are costly.

I found this, it is cheap and reliable and I have tried it.

Behringer UCA222

This device can be used for recording input from mixer and output the audio signal to mixer. It acts as a interface for the conversion of analog to digital. Please refer to manual for more information at this link. Furthermore, it can be purchased online via Lazada website.

 Using mixer for recording to PC

Procedure to use is simple. Simply plug-in the device into USB port, Windows 7/ Mac supported, no need to install driver. When there is needs to listen from the headphone, turns ON the device. Furthermore, there are many freeware that support this device. You can refer to this Youtube video clip below:

Review of the device

Recommendation of freeware for recording??

  1. Audacity
  2. Simple MP3 Maker
  3. Others

What type/ brand of mixer do you used??

Answer: Any mixer will do. But how to record with high quality sound??

Okay! The church I attend is using ALLEN&HEATH GL2400 mixer, 42 channels. Where should I connect then?

Allen & Heath Mixer

Back of the mixer

The manual of the mixer can be downloaded at this link.

Question: Which one should be used as output for recording? How about either one or two of the Auxiliary (1,2,3,4,5,6)?
Answer: Yes. But You will lost the port for Aux which you might use in the future or any monitors.

Question: How about using the track out?
Answer: Yes. But you might be more noise, during worship, the vocal might be imbalance. It could be louder or softer. Is there any alternative?

Using Matrix of the mixer

Please refer to this slide below for more information:

Slide uploaded by

Youtube video explains the definition of Matrix

Advantages of recording using Matrix

  1. Select the signal you want to be recorded. During grouping 1-2, 3-4. Let say Grp 1-2 is vocal, Grp 3-4 is instrument. If the vocal is louder than instrument in recording signal. Hence, the sound man needs to turn up instrument and reduce the vocal. The turning of volume will not affect the FOH.
  2. Mixer will have spare AUX to be used if Matrix is selected for recording.
  3. The sound man also can add additional signal into the matrix during recording, for example the effect. This can increase the dynamic of sound during recording.

That all guys!! If you need any further information on this kindly contact me by email or phone number as shown at the right corner.

Happy New Year 2017. This is my first post this year. Have fun and happy mixing.

Catch out for my next post soon!!!

Friday, 25 November 2016

VNC (Virtual Network Computing) for Raspberry Pi

It's been awhile since my last post. Today, I will talk about the VNC of Rpi. This post was cited from this link.

Headless Connection

By using this method, we do not need to connect the Raspberry Pi to any keyboard, mouse and monitor. You can access it from any PC, Android device or iOS device.

My current Rpi setting: 


1. Raspberry Pi Ver3.
2. Wireless Dongle
3. Power adaptor


1. Install SSH software in your Raspberry Pi. Please refer to this link for details.
2. Find the IP address using command ifconfig. Please refer to this link for details.
3. Install tightvnc in the Raspberry Pi. Please refer to this link for details.
4. Setting fix IP address for Rpi. command nano /etc/network/interfaces and add under wlan0 the text below:

5. Restart and install VNC on your PC and gadget. It is available at playstore for Android device.

6. Done. You are ready for VNC of Rpi.

Please contact me if you more information on the setup.

Stay tune for more posts.

Monday, 22 August 2016

Control DMX Lighting Using USB Interface


Have you ever think of using PC to control DMX lighting fixture instead of using DMX mixer? Recently, I bought lighting fixture and USB to DMX converter to try control using PC.

Item Required:

1. USB to canon jack (DMX).

2. Lighting fixture

3. Freestyler software

This software can be downloaded from: http://www.freestylerdmx.be/ It is free for download. However, you can choose to donate to the developer.


1. Connect PC to DMX lighting using USB cable. Launch FreeStyler software, at the interface setup choose uDMX and click save.

2. Next, go to add and remove fixture. Choose the lighting fixture that is similar to the one you connected. For example, if it is 6ch. Choose other brand with 6ch, it is fine.

3. If you have more than 1 lighting. E.g: 10 lighting fixture. Split it, 5 left same address A001 and 5 right same address A009. How to set the address? The address is shown in the fixture in dot matrix display or DIP switch. Click this video for setting up address.

Figure below shows the lighting fixture address.
Note: Most of the lighting fixture has own program. E.g.: static colour light, fade in out light, fast transition light, sound detector light and etc.

4. After all these are done. Now, lets go to program a chase/ Cue. Select different colour of light, click add step. Select the desire fade and speed. Once done, save it as cue.

Once done, try it and you will like it. Go to CUE page and the speed of the CUE is adjustable as per highlighted part.

I have done my demo in one of the church in Kuching. Please click on this video.

And my PC setup looks like this:

If need further advise and suggestion. Kindly contact me. Thanks

Sunday, 12 June 2016



On the Year 2013, I attended the Chargeman Underground cable course. The Chargeman course required strength in practical. It is the same and apply to all Chargeman related courses. The basic requirement for the Sarawak Regulator, Electrical Inspectorate Unit (EIU) is that the person needs to have at least 3 years experience in electrical field.

For those who has Degree in Electrical Engineering, taking this course can be helpful when you go for BEM PE interview or even Electrical Supervisor/ Competent Electrical Engineer in the future.

The Course Content (Theory)

Section 1
1. Electrical Safety & Electricity Rules
2. Underground Cable Basic Testing

Section 2
1. Conductors
2. Conductor Screen
3. Cable Insulation
4. Insulation Screen
5. Bedding
6. Armour

Section 3 Cable Laying Methods
1. Cable Laying Methods

2. Direct Laid System
3. Duct Laid System
4. Site Inspection and Trial Holes
5. Minimum Installation Bending Radii
6. General Wiring Cables
7. Laying Cable in Pipe and Duct
8. Protection Cover

Section 4
1. Conductor Lossess
2. Skin Effect
3. Proximity Effect
4. Sheath Losses

Section 5
1. Cable Sealing
2. Installation of Cable Sealing End Caps
3. Cable Seal XLPE and Lead Sheaths
4. Civil Works

Section 1 - 4 come out in the exam.

The Practical
1. Cable Sealing End Caps

2. Flaking and Unflaking of Cables

3. Cable laying

Please click video for the short clip on CH U/G practical.

If you need further explanation, please contact me by email: yhckelvin@gmail.com

Tuesday, 12 April 2016

Raspberry Pi Customer Satisfaction Survey

This is a simple project to capture customer satisfaction survey using Raspberry Pi. This survey only has 5 rating ranging from very poor, poor, average, good, & excellent.

Figure 1 Rating of Customer Survey Satisfaction

Material Required
Figure 2 Raspberry Pi connected to push button & 16X2 LCD

1 - Raspberry Pi Ver B.
1 - LCD Monitor, 1 - HDMI cable, 1 - 5V Adaptor, 1 - keyboard, 1- Mouse, 1 - Wireless Dongle
1 - Breadboard
1 - 5 Push button (5 rating selection)
1 - IDE Cable
10 - Male to male jumper

Source Code & Result
Figure 3 Declaration of GPIO for both LCD, Push button, & LED

1. Once a customer finishes his/ her consultation with the customer service personnel. The person will ask the customer to rate the customer service by pressing on the push button.

2. When the customer press the push button for 1s (e.g. Average). It will appear on the LCD screen, LED will ON for awhile and captured at the data log.

3. In the end of the month, the officer in-charge can tabulates it using excel sheet.

1. Reduce paper work
2. Convenient and more I.T savvy

Figure 4 Data Log Captured with time frame

Short Video Clip:

Figure 5 Video clip of the system

Please contact me at:
011-38660076 or yhckelvin@gmail.com
For more information on the source code and hardware

Thursday, 17 March 2016

Sound System for Studio in Gymnasium

Welcome again to Audio & Visual blog, this week I would like to share with all of you regarding the sound system for the studio. Before that, what is the criteria for it?
1. Less humming
2. Good quality cordless microphone
3. Good Sub woofer for better bass (keep the people excited and more energetic in exercise)

Case study, give comment and improvement on one of the exercise facility (gym) in one of state in Malaysia.

Figure 1 Mixer and Amplifier of Sound System

This set of sound system looks okay. It comes complete with mixer, compressor for the main speaker, amplifier, cordless microphone, DVD player.

Figure 2 Closer looks of the mixer (4 Channels)

Figure 3 Two types of transmitter are used in studio

Figure 4 Type of microphone used

This set of system is okay but however, the type of wireless module used are not good enough in such a way that the sensitivity (gain). Turning on too loud will cause humming/ feedback.
I suggest to use better wireless module (e.g: Senheiser or Shure) and the better wireless microphone (e.g: aeromic).

Instructor is the person that required good microphone during the exercise. This is important when sweat stick on the microphone cable and microphone. Hence, it is essential to have sweat proof microphone and the wireless module (transmitter) to be attached behind the microphone. Figure 5 shows the recommended microphone to be used by instructor. He/ She will not feel the cable disturbing and more convenient in teaching the class.

 Figure 5 Suggested wireless microphone

Stay tuned for more blog.

Sunday, 14 February 2016

Loud or Soft Monitor Speaker for Vocalist in the Church's Setting?

It is quite common for backup and worship leader to say "Guys, I cant hear myself can you boost the monitor volume". Does monitor volume so important and affect the worship session?

What is a monitor speaker?
Monitor speakers are designed to provide a flat frequency response so that that the audio signal is in original condition. The default monitor design does not have artificially boosting bass, treble or other frequencies to avoid resonances from the speaker and sound "nice".

Figure 1 Sample of Floor Monitor with Wedges for Vocalist

There are two types of speaker, based on where the signal is amplified. The characteristics of each type is described below.

1. Passive speakers

This types of speaker only provide basic feature of a speaker, in other words without built in amplifier.
Figure 2 Passive speaker setting

2. Powered speakers

This types of speaker does not need any external amplifier. It has built in amplifier and power cord needs to be connected to it. It is also called as active speaker. Most of the portable speaker is this types of speaker.
Figure 3 Active speaker setting direct from mixer

Figure 4 Active speaker setting direct connect to Microphone

Let me share with you the case happened in my church for vocalist floor monitor. All three monitor shared the same line/ Aux and it has caused inconvenient to everyone. Worship leader always complaint that the backup singer is louder than him/ her during the worship session. Nevertheless, backup singer also complaining not hearing themselves. In this scenario, shall we 'sacrifice' the backup singer and focus on worship leader only?
Solution 1:
Split the monitor into worship's leader monitor and backup singer's monitor. In this case, the worship leader will have his own monitor and backup singer will share one or two monitor among themselves.
Solution 2:
Always set the volume of worship leader louder than the backup singers. Take note that the backup singers volume must be satisfactory to them.
Solution 3:
In ear monitor for each singers on stage.

In the end, I chose solution 1 because that is the cheapest way (without purchasing new equipment, perhaps just one cable)

How to ensure the monitor volume is suitable?
When performing sound check, sound man needs to lower the volume of FOH. From there sound man will fix the suitable volume for the monitor based on singers feedback.

For more information, kindly contact me. Kelvin Yong