Home Theater Audio

Receivers, Separates, and Sound Options

Choosing the main audio component for home theater and sound playback formats can be a little intimidating, but also fun once the pieces are set in place.

Depending on budget and desire for certain components, buyers have numerous choices on the audio side of home theater entertainment. In the beginning, especially with a low budget in hand, it’s better to start off simply.

Receiver Or Separates: The Oldest Question In The Book

This is one of the oldest questions about home theater audio. Consumers read reviews and use their own experience and preferences on which products to buy. Some people prefer Yamaha, while others prefer Denon. Others may prefer higher-priced separate components and skip the big name brand companies. There are supporters on each side of the issue and the battle won’t soon die down.

A receiver can be the core of an audio system, offering the ability not only to decode digital audio formats found on DVD and Blu-ray disc but can be used as a radio and can send video signals to a high definition display. The advantages of using a receiver lie inconvenience, price, and (usually) easy use, plus the ability to decode the current sound formats. They can be purchased locally or online for reasonable prices. A receiver can be a fine choice in starting a new home theater system, or in upgrading a current one. Keep in mind that audio signals through a receiver that digitizes are never sounded good.

Some audiophiles may prefer using components to separate traditional two-channel music from the multichannel sound. Separates can, depending on the company that makes them, sound superior on two-channel recordings. The idea here is to separate analog sources like an LP or analog cables from a CD player or computer (run via USB to an outboard digital-to-analog converter) into a pre-amplifier. There is also the option to add a more powerful amplifier to the system. Audiophiles still can still use a receiver or dedicated surround sound processor for decoding DVD and Blu-ray discs as long as the receiver has a pre-out jack.

Sound Formats

Here’s a breakdown on the most common current sound formats. Each format can vary in how many channels they can play back, from 1.0 (mono) to 7.1 (seven channels, plus a subwoofer track).

DVD

·Uncompressed PCM (pulse code modulation)

·Dolby Digital

·DTS (Digital Theater Systems)

Blu-ray

·Uncompressed PCM (pulse modulation)

·Dolby Digital

·Dolby TrueHD

·DTS-HD Master Audio

There’s been debate over which sound format is best. Each has its merits. What are the differences in these sound formats?

Uncompressed PCM

Uncompressed PCM sound is the most accurate method in hearing a movie soundtrack. Sony, Disney, and Warner Bros. home video released many of their early Blu-ray discs in this format. It’s essentially the same as getting sound from the original studio mix. But in the last year, all of the studios have been releasing their Blu-ray discs in either Dolby TrueHD and/or DTS-HD Master Audio. PCM tracks found on DVD are usually featured on concert videos. PCM can sound superior to any of the compressed sound formats if they’re mastered properly. PCM can also sound cleaner and offer better sound staging than the compressed audio formats.

Dolby Or DTS

Dolby and DTS compress the sound. In other words, those formats take out what the human ear apparently can’t hear. This is very similar to how MP3 files work. To some, there is no difference in PCM versus any of the compressed sound formats. To others, there is a difference. Compressed sound takes away the clarity and dynamic sound quality found on many movie soundtracks.

Dolby Digital is perfectly adequate for DVD, but it does have some shortcomings. The audio is highly compressed, and depending on the soundtrack on how it was mixed and then presented on DVD, can sound just ok or very good. Audio playback can range from a paltry 192kbps (kilobytes per second) to 448kbps.

DTS is an alternative, and to some, superior to Dolby Digital. This format still compresses audio, but not as severely as Dolby Digital. The sound can be louder and clearer in some cases, but not all.

Dolby TrueHD or DTS-HD Master Audio

On Blu-ray, Dolby TrueHD and DTS-HD Master Audio have the ability to present highly improved sound quality over DVD. Each format runs at a high megabyte per second rate, letting the sound breathe and not sound trapped or bottled up.

These formats are advertised as being identical to the original sound mix, but that can be debatable in some instances. With time-and-phase correct speakers, like those from Vandersteen or Thiel, some of these soundtracks may sound a bit compressed. On other speakers, they may not. Both formats, regardless, are a huge improvement over the audio featured on DVD.

Depending on the original mix, or how the DVD/Blu-ray discs were mastered, not all soundtracks will sound excellent. Some titles may have been mastered at a lower volume, or some older titles may sound a bit distorted due to their original recordings. Some titles may have been recorded poorly, to begin with. Just be aware that not all movies will blast everyone out of their chairs, and weren’t meant to.

Audio Field Recording Guide

How to Capture Everyday Sound Effects and Ambience Outdoors

Learn how audio location recording in typical outdoor locations can enhance home-made podcasts and video recordings.

Recording audio on location is a great way to document the essence of many urban spaces, add life to podcasts, and improve the quality of video recordings. Modern audio field recording gear is much cheaper, smaller and less obtrusive than before. This is an introduction on how to get good sound outdoors.

Recorder and Microphone Types

For urban field recording, a good choice is a small field recorder using memory cards of the same type as used in digital cameras. Something like a Zoom H2 is a good combination of stereo microphone and recorder all in one that fits in the palm of your hand. This gives you more than 2 hours of recording time on a 2GB SD card. Similar field recorders use Compact Flash cards.

Get closer to the Sound Source!

The first rule of audio field recording is to get close to the subject, particularly if it is dialogue. To record speech, the microphone should really be within a couple of meters of the speaker. Any further and the speech will become muddied by ambient noise; and particularly indoors, reflections off hard surfaces can make the speech indistinct if the microphone is much further away from the subject than the nearest wall.

Don’t hold the microphone

Do not let anyone hold your microphone. It turns vibrations into signals on your recording, and that includes the sound of the muscle tension in the hand. Use a tripod or stand to hold the microphone close to the subject; this will result in a better recording than if someone holds it.

Move away from unwanted noise

In an indoor setting, you can usually turn off unwanted noise sources like a radio or the air-conditioning. Outdoors you can’t usually do that, so you have to move away from noise sources and closer to your subject. The ear is very good at discriminating against extraneous noise, so you have to listen critically, not just for what you want to hear, but also to check there is not too much of what you don’t want to hear. Or record a section and listen to the playback – it is always better to get the cleanest original recording.

Wind noise is often a problem. Most field recorders come with a basic foam windshield – these are typically good for wind speeds up to about 5 mph. Any more and you will have problems with a rumbling sound in your recording – try and move to a less windy location or wait till it dies down. Alternatively, shield the mic with a ‘tent’ made of cloth like a T-shirt held on a wire frame.

Use the manual record level, not automatic

Automatic record level sounds a great idea, but it saps the life from a recording. In a typical city location, as soon as the talent stops talking, automatic record level winds up the levels, boosting things like traffic noise to the same level as the speaker’s voice. When the speaker starts again, the traffic noise is dropped, weakening the continuity of the recording. With digital recording, simply allow plenty of headroom and lift levels in editing.

Record uncompressed audio

Recording in a compressed format like mp3 or Windows Media reduces the quality of your recording, making it harder to filter and recompress without distortion.

Work within the limitations of your equipment

If you want to record wildlife sounds like birdsong or very quiet or very loud sounds you will need different techniques. The simple techniques described here will let you record audio for podcasts, photography, and videography under typical field conditions. If the audio will be synchronized to a video recording, a clapper board and spoken take number help match the recordings up.

Conclusion

These simple techniques will help you capture good audio from outdoor locations, for podcasting, video and documentary purposes.

How to Identify If Audio Equipment Is Grounded

Know if Hi-Fi Separates are Earthed or Ungrounded to Avoid Hum

Knowing whether there is a ground connection to Hi-Fi equipment can be useful when tracing ground loops and hum problems.

Is it worth being aware that mains-powered audio equipment comes in two main variants when it comes to tracing hum problems in domestic Hi-Fi systems? There is no performance difference – it is perfectly possible to make good sounding audio equipment which either has a mains ground connection or to make it without a ground connection.

However, using more than one item grounded to mains earth in a domestic audio system can lead to ground loops (also known as earth loops) which can lead to hum in the system. It is, therefore, necessary to identify whether Hi-Fi equipment is grounded or ungrounded.

How to Identify Audio Equipment that Does Not Have a Mains Ground (Earth) Connection

The easiest and most sure-fire way to identify a piece of ungrounded equipment is to look for a two-pin mains plug. A two-pin mains plug by definition has no earth connection, this piece of equipment will, therefore, be ungrounded.

In some countries such as the UK, nearly all mains plugs are three-pin, making this harder to see. For equipment with detachable mains cables, there is another plug in the system – the chassis-mounted plug on the equipment itself that the mains lead plugs into. If this is two-pin then the piece of equipment is ungrounded.

Other things to look for are a mains cable that has just two cores – these are often of a flat or oval cross-section rather than round cross-section. In the UK if the equipment is described as Class II or double-insulated it has no ground connection. Audio equipment that is powered from a wall-wart or plug-in power supply almost always does not have a mains ground, though there are some very rare exceptions.

How to Identify Audio Equipment that Has a Mains Ground (Earth) Connection

Unlike the infallible test for ungrounded equipment, it is not possible to conclusively state that a piece of equipment is grounded just because it has a three-pin power plug. However, if it is described as Class 1 insulated in the UK it is definitely grounded. Likewise, equipment that has a round cross-section non-detachable mains cable is likely to be grounded. The only way to know for sure is to perform a multimeter test.

How Electrical Safety Works in Grounded and Ungrounded Audio Equipment

There are two accepted ways of keeping people safe from mains power. One is to connect all exposed metal to the mains safety earth, which is carried on the third prong of the mains plug. The alternative, depending on the particular country electrical code, is to ensure that all mains power connections, live and neutral, are isolated by at least two insulating layers, one of which may be air. Such equipment may have just a two prong power cable.

How to Avoid Ground Loops in Hi Fi Equipment

Make sure that only one piece of equipment in the Hi Fi system is grounded – preferably the amplifier or control unit/pre-amplifier. If more than one piece of equipment is grounded, then plug the grounded components into the same distribution board or wall socket pair to minimize the ground loops and susceptibility to hum.

 

Secure Digital Memory Card (SD Memory Card)

The SD memory card is a special version of the MultiMediaCard. MultiMediaCards can also be used to store copyright-free content in devices with SD card slots. Starting in the 1st quarter of 2001, EMTEC will offer storage capacities of 32 and 64 megabytes. The SD memory cards cannot be read by the older MMC-compatible devices