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The Really Easy Guide
... to choosing and using an AV receiver
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by: Carol Mazur
Audio-video receivers are unassuming pieces of gear that provide the muscle behind making sound happen in home theatre situations. They provide a central connection point for all the products in your system and act as the nerve centre of the whole movie-making experience.
 They also act like a director, handling all surround sound processing and switching between sources and speakers, controlling how each speaker operates and generating sound and acoustic output that seems to put you front row centre of a live performance, be it a movie theatre or music concert.
In many ways it's the maestro of your system and it does all this quietly, efficiently and in the background. And while you can get along okay if you want a lo-tech home movie experience by plugging your DVD into your television and pressing the play button, if you want a real home theatre experience you'll need to add an AV receiver (along with a television and an array of speakers).
Here's how you go about getting one that's going to delight your senses and minimise the dent in your bank balance.
First up your budget. As a rule of thumb, which means it's a guide, I recommend you allocate around 30 percent of your budget to your receiver. This means that at the popular system price point of $4000 your receiver will soak up $1200 of the total cost. The DVD player and speakers should be allocated around 20 per cent and 50 per cent of the budget, or $800 and $2000 respectively. A subwoofer is not factored into this equation.
Next, power output. Don't get hung up on pure power because there are other perhaps more important factors to consider. In fact, the way the power stages are constructed within a receiver can have more bearing on the quality of sound than sheer grunt. And you should know that to get a discernible increase in perceived volume you will need to effectively double power output
Compare the power of receivers when quoted as a 'watts RMS' rating, into an 8 ohm speaker resistance, with all five channels driven, across 20Hz-20kHz (which is the operating rating) at the lowest distortion. You don't need to know what all this means, just that it provides the most realistic reference to compare receivers.
Like I said, d too much by small power differences because there's little audible difference between a 100 watts per channel receiver and a 120 watts per channel. Rather, look for uniformity of power across all channels and other factors that make the receiver sound louder, like low distortion and any noise factors. Ignore totally any AV receivers that are rated as 'peak power' or 'maximum output'. Then, after these things have been considered and, all things being equal, buy the receiver with the most power.
If the unit has a good quality electronic section the sound will appear cleaner and louder more detailed and simply better. And that's what you should be after.
Now to surround sound decoding. You'll get Dolby Digital processing (also know as AC-3) and its relatively lo-tech brother, Pro Logic, as regular inclusions. Dolby Digital is the standard audio format for DVD in Australia but DTS Surround is another digital audio format which is gathering support. If it comes down to choosing between two units that are identical except for the DTS capability, buy the unit with DTS.
There's a new format on the market too, Dolby Pro Logic II, which effectively eats its predecessor for breakfast, but which isn't included on all machines at this point in time.
Developments in home theatre surround technology have actually reached a 'hole in the head' stage (you know, we need another - insert technology - like a hole in the head). But the new Dolby Pro Logic II system offers clear sonic benefits to us consumers and movie lovers and is a very thoughtful implementation of technology to boot.
Why a new surround technology? Well everything about home theatre technology has improved significantly over the past years, particularly in the way content is created and dispensed, and it's set to continue with digital technology making its way into every aspects of entertainment at home. Pro Logic II is there to elevate the state of play in matrix decoding, which is the greater majority of existing movie software.
It handles (and more often than not enhances) a wide variety of movie and music matter, addresses our expectations of 5.1 channel performance, is workable over a range of products (home theatre, computers, headphones), is a cost effective addition to those products and is simple to understand and implement.
Pro-Logic 2 keeps the original spec of its predecessor, but adds new spatial, directional and soundstage elements to the reproduction of movie soundtracks, and is engineered to enhance stereo music by creating a pseudo 3-dimensional presentation of the sound stage.
The movie reproduction side of Pro Logic II's operation is automatic to cope with different program engineering techniques and to provide consistency of sonic results. The music mode, however, has manual override of functions for tailoring to personal preference.
The dimension control adjusts the front to back balance of the soundfield. Centre width control
varies the left-centre-right effects of the front speaker information. In panorama mode the stereo stage is enhanced to include the surround speakers and create a sonic envelope. Music mode introduces a mild high end filter in the surround channels to create a smooth natural sound effect. A delay effect helps improve the coincidence of music sounds for as many listeners as possible. You will also want to turn the auto balance function off when listening to music because vocalists and musicians are often placed off centre in the stereo stage presentation. In fact the same can be said for movies, but perhaps to a lesser extent.
But in this area of the AV receiver market (close to, but sub-$1500) you could encounter AV receivers that offers a variety of enhanced digital surround systems. Their relative worth is in the eyes of the beholder. They do introduce an element of future proofing for the relevant unit, but you will also need to invest in additional speakers to avail yourself of the new formats.
Dolby Digital ES is the same as Dolby Digital 5.1 but has an extra rear centre channel to create 1 6.1-channel system, that creates a stronger link between the front and rear surrounding effects speakers. DTS ES adds a similar 6.1 channel function to the DTS surround sound system.
Then there's s a bunch of 7.1 channel formats and Lucasfilm THX joins in this fray. Here you get two rear centre channel speakers instead of one, presumably for that extra added dimension to your soundtracks. Like I said, try before you buy to assess the relative and relevant a]value of these features.
THX is a high quality system developed by Lucasfilms that aims to refine attributes of the sound after it has been decoded and processed. I believe THX has a lot to offer home theatre but other people question it's relevancy. However, due to compliance costs it's mainly found in upmarket models where it's often a standard inclusion.
Inputs! We need inputs! Make sure you're equipped to connect every piece of equipment you have and intend having - those that make sound, those that make video and those that make both. The ability to accept generic 5.1 (or 7.1) channels will help make the unit more future proof. The capacity to relay component video is high on the list of desirables and S-Video inputs will improve connection flexibility.
Outlets should be the highest quality possible, particularly the speaker connectors where you should look for heavy duty gold plated binding posts for the front speakers as a minimum and preferably on all channels.
Your AV receivers must have a separate outlet for driving a subwoofer (the speaker used to generate low bass sounds that create so much of the sensation in home theatre). Some models have outputs for more than one subwoofer, particularly more up market receivers.
Selecting from the bundles of other features available to you is pretty much a matter of personal choice. So play with prospective purchases and figure out if they're worth spending your hard earned readies on.
All the advice in the world isn't going to help if you don't know how to evaluate products to make a good choice on the gear you want, so here's what to listen for when assessing components.
The best advice is chose a known name brand, then buy it from a specialist retailer. Get the backing of a decent warranty and access to servicing that's close to you - most gear is very good but a bit of planning doesn't hurt.
When auditioning the gear you like, use DVD movies and music performances that you know. This way you'll be familiar with the sounds and effects and have a better handle on the performance of the units under test.
You must be able to hear and understand the dialogue. A muddy centre speaker will cause frustration. Pans from side to side must be seamless and not jump from one speaker to the other. Effects off-screen must seem to be in the distance if the onscreen image dictates or close if that's what's warranted..
The surround sounds should stay cohesive and in-place as you change listening positions and not produce a narrow listening sweet spot. Bass must be tight and clean and deep enough to add realism to movies and music where relevant. Boomy bass sounds impressive, but it's rarely enjoyable in the long term.
The last advice is to take your time when shopping for gear (buy in haste, repent at leisure) and don't shop purely on price, rather pay that little extra for the support of a good retailer.
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