Archive for July, 2010

What Do Amplifier Classes Mean?

Tuesday, 27 July, 2010

The different circuitry design within an amplifier can be determined by classes. The audio amplifier’s class refers to the output stage of the amplifier. There are several classes:

Class A – Class A amplifiers produce very low distortion. The distortion is the lowest when the volume is low. However, Class A amplifiers are extremely inefficient, thus they are not suitable for designing high power models like most multi zone amplifier in the market.

Why do they manage to produce low distortion? The transistors in Class A amp are biased in a way that they are only half working when the device is idle (at this point the semiconductor devices are most linear in behavior). From this, a lot of power is wasted even though there is no audio from the device.

Due to the working mechanism of Class A amps, they are often used for signal level circuits. Premium Class A audio amp are sometimes used by the choosiest audiophiles.

Class B: Class B amp are meant for lower cost circuit designs. Sound quality is not a priority. However,do bear in mind, Class B amplifiers are more efficient than Class A amplifier. However, distortion is rife when signal level is low (the term is called “crossover distortion”).

This is selected when design cost is emphasized. This class of amp is formerly used in pocket transistor radio, clock radio and anything portable whereby sound quality is not important.

Class AB: This class is widely used in home stereos and normal audio amplifiers. Class AB amplifiers boast about the best of A and B. Think of the efficiency of Class B and the better distortion performance of Class A amplifiers.

In AB amplifiers, distortion would deteriorates when the signal gets lower. They usually make use of pairs of transistors which are biased slightly “on”. The reason is to eliminates crossover distortion which happens in Class AB amps.

Class C: Never used for audio circuitry and usually operate the output transistor in a state that produces tremendous distortion. C amplifiers are most commonly found in RF circuits whereby such crude signal is acceptable. They are extremely efficient though.

Class D: This class of amplifier is the most employed in Multi Zone Amplifiers and Multi Zone Audios. D amplifiers use a different method of amplification as compared to earlier classes mentioned.

Class D amplifier operates the output semi-conductor devices as switches (On or OFF) which is vastly different from Class A,B, AB and C operate in the linear mode. Class D ’s input signal is compared with a high frequency triangle wave, resulting in the formation of “pulse width modulation (PWM) type signal. This type of signal is also known as ‘digital’ signal by layman.

PWM signal would go through a special filter which removes all unwanted high frequency by-products of the PWM stage. The output of the filter would drives the speaker. One of the major advantage of using a Class D amplifier is its high efficiency or low power wastage.

Learn more about amplifiers in http://MultiZoneAmplifier.com/.

OmniMount Speaker Stands

Monday, 26 July, 2010

There are many great OmniMount speaker stands to choose from, but the most popular two are the OmniMount Gemini and EL0, which we will describe below. All in all, this is one of the favorite speaker stand brands, which beats many of their competitors both, by price and value.

OmniMount Gemini

This is probably the most favored model. They are affordable and attractive. The units have 4 interchangeable base inserts, making it easy to match them with most designs (you can match with your television stand or anything else in the room). They also have a beautiful finish. These stylish and functional stands can accommodate any large bookshelf speakers. The wires are hidden in thick tubes, and plastic caps will hold the wires at the base. They are easy to assemble – they come with one of the easiest to follow instruction manuals. All you need is a screwdriver and pliers (for the wires).

These stands have carpet spikes included, a wide base, and wide speaker platform, making them sturdy and safe for your speakers. The weight of bookshelf speakers creates a steady base, and the stand will not wobble. They can handle the weight of some of the heaviest speakers. Their height can be adjusted either to 25″ or 32″ from the floor (the recommended height for bookshelf speakers is 30-33″).

OmniMount EL0

This is the second popular option for front/surround speakers. It’s a floor-standing mount with an attractive high-gloss black finish; it’s made of tempered glass (base) and steel. This unit is also easy to assemble. It has an adjustable height. It’s stable on carpet with its rubber feet and a large glass base. It has a cable management system to accommodate a 14 gauge wire. These OmniMount speaker stands have 3 mounting options.

If you’re looking for OmniMount speaker stands you should probably visit the website I personally use to do all of my own speaker stands shopping. It’s kind of like a hidden secret and I don’t know how long it’ll be live so make sure you check it out right now to get some killer savings: http://www.woodspeakerstands.com/omnimount-speaker-stands.html

Front Home Theater Speakers – Information on Front Home Theater Speakers and Set Up

Friday, 23 July, 2010

If you are looking for front home theater speakers then you are most likely wanting to buy separate speakers instead of satellite speakers. Satellite speakers can come into packs of 3 and as many as 8. This might be a better option than just buying the front home theater speakers. The reason being that you would be sure that all of your speakers work together properly.

A home theater system can make a real difference in your home entertainment experience. Instead of having speakers that may be distorted and less than satisfactory you can have speakers that are high quality – high quality like the movie cinemas. While it may seem like a little bit more than you want to spend one speakers if you get a good quality sound system in your home then you might not have to spend so much money going to the movies. This in the long run may save you money.

There are a couple things that you should consider while you are looking for the correct speakers for you. Let’s take a look at those and then hopefully you will be able to make a more informed decision.

#1 Warranty

A very important factor that you want to take a peek at is the manufacturer’s warranty. This warranty can ( in my opinion ) show you a lot about the quality of the speaker or speaker system. Look at it this way – if the company will not back the speakers up with a good warranty then you might not want to put your faith in them either. There are many different warranty ranges on speakers but the most common is a 3 months warranty. Anything less than a 3 month warranty should be thrown out. The warranty depends on the company and you will have to look at speakers individually.

#2 Placement and Fit

Another factor in your next speaker purchase would be the placement and fit of the speakers. Even if you have the best sounding speakers you can not enjoy them if they do not fit in your entertainment center or if they can’t go where you wanted them to be placed. Sometimes when we get excited about our purchase we don’t think about this factor but you need to remember this one. When buy online the website that you purchase from usually has the dimensions of the speakers and you can check them easily there.

One more thing to think about when you are buying speakers is the set up of your speakers. If you have a full speaker system then you should be able to put the center speaker either above or below the TV and then place the right and left speakers at the same distance away from each other… the tweeters should be at ear level when you are sitting down. You can easily place the subwoofer out of the way – like in a corner,under a table etc. You don’t need to worry about the subwoofer placement that much.

Jessica Lauren is an expert in the area of electronics and specializes in helping people find cheap speakers. You can easily find out more about front home theater speakers by visiting Jessica’s website.