Audio Learning Series For Selecting Best Product - INDIQAUDIO

LEARNING SERIES

This series is aimed at providing insights on Audio domain while ensuring the ease of understanding. Don’t miss this opportunity of voyaging through maze of thousands of concepts, articles, thereby mastering the art of determining the best product. Your perfect setup is just few guidelines away.

  • Chapter  6  :   Selecting right speakers for a Stereo setup

    • Are you primarily into movies or music?

    • If you’re a die-hard music aficionado, you must select bigger tower speakers

    • If you are a movie-buff, you must undoubtedly invest in a configuration of bookshelf, towers and a high power subwoofer. If music is your thing, you may go for high quality tower speakers

    • Bigger speakers are less likely to be overdriven when compared to smaller ones

    • Bigger speakers with multiple drivers have better dynamics then 2 driver smaller speakers

    • Bigger speakers are versatile and provide flexibility to be moved to a bigger room later

    • One can never go wrong with bigger speakers as against smaller ones, irrespective of the room size

    • Bigger speakers inherently have better and refined bass since bass is a function of the cabinet volume and size

  • Chapter  7  :   Ideal Speaker Height  

    • Ideal speaker height depends on the design of the speakers, whether it is a point source or a line source

    • For point source, speaker height should be such that the tweeter is generally at the ear level of the listener

    • For line source, tweeter height is not very important since the speaker would have large number of tweeters and mid-range drivers in a vertical line

    • In a home theatre configuration, place the center channel speaker below or above the TV or below the home theater screen. As far as possible, it should be at the ear lever. Surrounds should be placed about 1 – 2 feet above the ear level on the rear and the side walls

    • Never place a small bookshelf on the ground pointing upwards. This will make them sound terrible. The bass will become boomy because the speaker is coupling with the floor. Treble will be weak because it's off axis. The situation will be more complex due to floor reflections

    • In case the tower speakers sound too bright with tweeters pointing at us, tilt the speakers slightly upwards by placing some cardboard or plastic sheets under the front rubber feet of the speakers. This will divert the high frequencies above the ear level, thus softening the brightness

  • Chapter  8  :   Speaker Placement and Imaging  

    • Speakers should be laid out so that they play along the length of the room

    • If possible, have a minimum distance of 1 foot between the speaker and the back wall

    • If the listening distance is equal to the distance between them, then higher toe-in is required

    • Toe-in is specific to speakers and the way they disperse the sound and their ON/OFF axis response

    • Place the speakers so that they form an equilateral triangle with the listener. Keep the starting toe-in zero

    • If the listening distance is much higher than the distance between the speakers, then zero to minimal toe-in is required

    • If you get too much of mid bass, increase the distance between speakers by 6 inch at a time until the sound is fairly balanced

    • For surround sound installations, the subwoofer should be placed at least 30cm from a corner to prevent unnecessary reverberation and echo

    • Lot depends on what kind of center image is preferred. For a clear and narrow center image, higher toe-in is required, for wider center image, less or no toe-in is required

    • Experimentation is required to finalize the toe-in. Usually, voice delivery should be around the center stage

    • If possible, have the setup done using REW and a calibrated Mic

    • For reducing room reflection, please refer to the Chapter 3

  • Chapter  9  :   Classes of Amplifiers  

    • Amplifiers can be divided into A, B, AB, D, G, H, I classes. But for now, we will focus on A, AB & D only since they are commonly available

    • Class A and AB belong to analog category

    • Class A draws full current even when no input signal is passed which gets converted into heat. The output devices (Transistors) are always kept ON so that they don’t go through ON/OFF cycle which keeps crossover distortion to the minimum making it sound more sweet

    • Due to inherent low efficiency of class A, high efficiency (>92 dB) speakers are recommended to be paired up with these amplifiers

    • Class AB draws majority of the current only when signal is provided. With no signal, minimum current is drawn. The output devices (Transistors) keep on toggling between ON/OFF cycle that results in a bit of crossover distortion. It is up to the designer to keep the distortion beyond the audible range

    • Based on the design, Class AB exhibits Class A characteristics at low outputs and Class B beyond that Hence, class AB are more versatile

    • Class D belongs to digital category and works on PWM (Pulse width modulation) technology. The output devices (Transistors) work at their maximum efficiency generating minimum heat. Since the pulses happen millions of times per second, it results in switching noise. To attenuate this noise, a network of Low pass filter and a complex feedback mechanism is implemented. Class D are normally preferred in active subwoofers and car audio due to their compact size

    • Class Ds are more of a design implementation whereas ABs are more of a grounds-up design. Hence, Class D will carry forward inaccuracies of the design being implemented, whereas AB being discrete, have ample opportunity to have the design inaccuracies sorted

    • Some Class D designs produce varying sound quality depending on speaker load and can become very specific to a speaker pair in terms of preferred sound quality. Therefore, majority of the people lean towards AB topology for home audio

    • As a ground rule, amplifiers should always be selected in conjunction with the speakers to be driven. Please refer to the Chapter 1 for the speaker selection & audition

  • Chapter  10  :   Choosing the Right Amplifier

    • You can barely go wrong with a high-power amplifier, since they have the benefit of good headroom for distortion free music reproduction.

    • It is not advisable to go with a low power amplifier as there is a risk of distortion due to clipping and maxing out the power during demanding music passage

    • Specifications (Power, THD, Linearity etc) of any amplifier only tells its capability and not how it sounds. That’s why personal audition is so important rather than relying on online reviews

    • The sound signature of an amplifier is dependent on its design, category, quality of components, type of feedback, slew rate etc.

    • For a simple setup an Integrated amplifier might be sufficient, but serious listeners might go with pre/power combination

    • Higher power amp will drive low impedance speakers with ease as they have lot of reserve power for that “Dynamic Shift” in the music resulting in impedance dips

    • Higher power amplifiers are also kind of future proof in case you decide to move to a bigger room with a large listening distance in future

    • Every increase of 3dB in the output, power required gets doubled. (90dB efficient speaker means speaker needs 1 watt to produce 90dB at 1-meter seating distance, 93dB at 1-meter needs 2 watts and so on)

    • Similarly, if the listening distance is increased, perceived loudness decreases by the order of 6dB with every doubling of the distance. 0dB at ref point (1 m), -6dB at 2 m and so on. So, if a speaker is 90dB at 1m, it will be 84dB at 2m and so on

    • If you are inclined towards Bi-amped setup, you would need at least 2 amplifiers or a single multichannel amplifier to drive individual speaker drivers independently

    • Bi-ampling is further divided into horizontal and vertical, which we will cover in subsequent chapters


DISCLAIMER : The above information is only meant to provide useful and helpful insights on the subject discussed and in no way meant to challange existing practicies, beliefs, products and processes.