22 March 2021

Acceptable noise (dBA)


 The above images extracted from : http://www.benjaminjaffe.net

dB(A) - the A weighted noise or sound measurement - is

  • its adaption to how the human ear responses to sound - the human hearing, and
  • the possibility to measure noise with "low cost" instruments

Maximum acceptable Equivalent Sound Level - Leq - at some locations:

 The above sound level extracted from: https://www.engineeringtoolbox.com/decibel-dba-levels

Caution:  Please be alert not to subject your hearing with a noise level of more than 85 dB(A) each day, doing so will increase the risk factor for hearing damage.

17 November 2020

Soundproof vs Acoustic treatment, is it the same?

This is a very common question, many will says that it is very easy to sound proof a wall, just add acoustic foam to cover the whole walls and that it. My friend, doing this does not make your room sound proof or the wall soundproof. all it does it, it just modify the sound reflect onto the wall i.e. it absorbed the sound. Acoustic foam is usually used for acoustic treatment.  Acoustic treatment is a method to control the echoes and reverberations inside the room. Whereas soundproof is about isolating the room from outside noise coming into or noise from inside going out of the room.   

Let us discuss some basic acoustic for us to get an idea and a better understanding of these confusing subject.

    Extracted from: https://auralex.com/alpha-dst-roominator-kit/

Acoustic treatment:

(the following statement is extracted from Acoustic 101(Auralex) by Eric T. Smith, page 6, 7 . 2014).

    One of the single biggest concepts to understand and appreciate is that (Auralex) acoustic foam, one of our core products, is not going to "soundproof" your room. It is an extremely effective absorber of ambient, reflected sound and helps make rooms "sound better." Acoustic foam does contribute some sound isolating properties (mostly high frequencies), but is not sufficient by itself to keep sound in or out of a room. 

    Thicker acoustic foam is better at absorbing low frequency sounds. Controlling reflected sound within a room is extremely important in producing good sounding recordings. 

Image extracted from : https://all.biz/tr-en/bondex-30mm-g278659

Sound Proof:

(the following statement is extracted from Acoustic 101(Auralex) by Eric T. Smith, page 6 . 2014).

• When sound strikes a surface, some of it is absorbed, some of it is reflected and some of it is transmitted through the surface. Dense surfaces, for the most part, will isolate sound well, but reflect sound back into the room. Porous surfaces, for the most part, will absorb sound well, but will not isolate.

• The best way to stop sound transmission through a building structure is to isolate the sound source from the structure before the structure has a chance to vibrate.

• Walls need to be isolated from ceilings and floors, usually by means of dense, pliable rubber.

• The main ways to minimize sound transmission from one space to another are adding mass and decoupling.

• Limp mass is most often better than rigid mass (actually, a combination of the two is really what you are after).

• Every object, every construction material has a resonant frequency at which it is virtually an open window to sound — kind of like a tuning fork that “sings” at its particular resonant frequency.

• Different materials have different resonant frequencies.

• Trapped air (a.k.a., air spaces and air gaps) is a very good decoupler.

• Airtight construction is a key concept. Sound, like air and water, will get through any small gap. (Sound can leak through openings as small as 1/32” – in some cases even smaller.)

• Sound bounces back and forth between hard, parallel surfaces.

Soundproofing is not an easy Job and it is recommended to refer the job to professional team or acoustic consultant who has experience building soundproof structure. It should by no mean attempted by DIY or laymen as there are many areas if not done properly can cause sound to leak through gaps or flanking path or faulty structure which may cost more to amend then to build. In addition, there are measurement (acoustic report) need to be carried out before and after the job is done. 

Reference :

Acoustic 101, Practical Guidelines For Constructing Accurate Acoustical Spaces by Eric T. Smith Edited by Jeff D. Szymanski, PE July 2004 Version 3.0


27 May 2020

Build an Online Radio

For those who are planning or about to plan to start an online radio, the above info will get you run at no time. Call the number or whatapps +60162798533 (Ts.C. G. Simon, Senior Broadcast Engineer) . We will help you get started and assist you in whatever question you may have regarding online radio.

27 June 2017

Guide to Mixing by Soundcraft

The Soundcraft Guide to Mixing

A great introduction to "how to use a mixer for live music production", for novices, or to get tips, or as an educational aid for Media Colleges and Schools. 
Even though the last update was in Jun 29, 2014 but the information provided in most of the videos are still relevant for beginners or armature or even for the experience sound engineer. 

02 April 2016

Amplifier (dB calculation)

There are two important dB calculation for amplifier output. 
  1. How many dB SPL between two wattage levels.
  2. The difference in watts that need to be achieved for a given change in dB SPL.
WATTS TO dB ( Watts to SPL):
You want to change a 100W amplifier to 350W amplifier. How many more dB you can get out of your loudspeaker?
Answer : dB = 10 x log ( watts 2 / watts 1) or 10 log ( 350/100) = 5.4 dB

20 January 2015

Handy dB Reference Chart

I have enclosed herewith one of the notes from the Seminar I did years ago in Sound Reinforcement System. I Thought this might be handy for those who wants to know how much power increase in relation to dB increase.

23 June 2014

Simple Tools

At present day, most of us involve in audio reproduction will certainly encounters problem with managing the audio for reproduction or processing. For instant, one of the most common fault is to do with ground loops which caused buzz, hum or hissing. A simple thing like cable defect, mismatch audio input level, improper cable conversion form balanced to unbalance, improper audio splitter can more or less introduce undesirable audio i/o which can degrade the quality of the audio.   

An example of such tools are: Rolls BUZZ OFF HE18, Rolls Cable Detect CT1 PRO, Behringer ULTRA-DI20, behringer CT100, Henry Engineering PatchBox II, galaxy Pro JIB/S 4 Way Splitter.

Hence, the following simple solution can somehow improve the audio ( i.e. removes buzz, hum caused by ground loop, matches level, detect faulty cables, convert high level to low level and so on and so forth).  I will discussed each one of these tools later. So in the meantime, stay tune.

30 December 2013

Newly installed Broadcast Conty

We have successfully completed the job of installing the above On-Air Studio on the 8 Jan 2014. This on-Air Studio is ready for use. Notice the mixer is embedded into the table and look more tidy without all the cables laying around/on the tabletop.

The conty is equipped with the latest professional broadcast equipment from branded name such as AKG, Allen & Heath, Warfadale, Behringer, HP workstation, Presonus, Dell workstation, Arrakis System ( Radio Assist Application ) and so on.

 Partially completed broadcast conty (refer below), just few days before Christmas ( on the 23 Dec 2013 ).
As seen above, the student are trying out the soon to be completed broadcast equipment.

08 October 2013

Radio Online Streaming Part 3

Steps 3:

WINAMP STANDARD (to download go to http://www.winamp.com/media-player/all ) Once you have successfully downloaded the application and you may run the setup program as shown graphically below:

A ) Go to www.winamp.com/media-player/all and
Click the “ FREE DOWNLOAD” to download the

 B) click OK.

C) Click “Next”

D) Click “ I Agree”

E) By default the destination folder of the
Winamp shall be located at c:\Program
Files\Winamp…you can change the location
but not necessarily, it best to leave as it is.
Click “ Next” to proceed.

12 September 2013

Constant Voltage Speaker System

Recently I was involved in setting up an audio distribution system (100V) and the hardest part is to choose the type of speakers that suit the client requirement such as wide dispersion speakers, horn type speakers, indoor and outdoor type, interior type wall mount speakers and so on and so forth. In the end I manage to figure it out and the result is shown below:

The total power of the speakers is 91Watt which is less than the PA Amplifier output power of 120Watt. The system should function as required and what important is the client satisfied.