The AV Receiver

NOTE: This is an update to an article from Urithi Magazine, originally written in 2017.

If you grew up in the 80s with a father who had an interest in home audio then this article should bring both nostalgia and a desire for what is informally called upgrade-itis.

In the “olden” days, you had “music systems” or, more formally, Hi-Fi systems that combined a radio tuner and cassette player with an amplifier and equalizer. Names like Aiwa, Hitachi, Siemens and Technics should spark the appropriate reminiscing.

Introducing the AV Receiver

When my friends have asked me what the “big black box” in my home is, and I reply with “an AV Receiver” that is usually met with a blank stare.

Does that help? Read on!

The music systems of the Eighties were usually stereo systems connected to 2 speakers. However, in the mid-90s, “surround sound” began to appear in home electronics, and consumer electronics supporting surround sound such as the LaserDisc and DVD became available. Also, advanced miniaturization of silicon chips improved computing power and made smaller home electronics possible.

So, now you had the ability as a normal consumer to have multiple electronics components and several speakers in your home “surrounding” you with sound.

The AV Receiver solves this integration by acting as a central hub. All your devices plug into the Inputs. You connect your display (TV, Projector) to the Output. You then connect your speakers and now all your devices can be viewed on the display unit and heard on your speakers.

The “Home Theater”

I know some of you are saying that you already have something like that. You went to your neighbourhood supermarket and bought a “DVD Home Theater” manufactured by Sony, Samsung or LG.

It has 5 speakers; a “subwoofer”; a DVD Player; an inbuilt radio, and I can plug in my PS3 and play games on my flat screen TV…. So what’s this dude talking about?

[Random citizen]

Why an AV Receiver?

Your average consumer “Home Theater in a Box” (HTiB) is a pre-packaged throwback to the 80s “music systems”. And it works. It achieves all you want but, because it’s pre-packaged, there are certain corners that will bother you if you’re very picky about the quality of your sound, video and media components.

Once you buy an HTiB from LG, the choice of components is forced. Almost all the time, you cannot use a better DVD player from Hisense, or better looking speakers from Pioneer, or a more powerful (active) subwoofer. With an AV Receiver and separate components it’s easier to replace a CD player or a new Left Front Speaker than with the boxed solution.

Another shortcoming of the box is that the power specifications and actual audio output are very deceptively marketed. Have you ever seen a 1500w-rated HTIB and yet the entire box – speakers, subwoofer and amplifier – weighs about 4kg? I’m sure electronics engineers laugh when they read such things. Manufacturers cheat by measuring Peak Maximum Power Output (PMPO) which is the maximum power possible over a span of microseconds, which is total nonsense in the real world. So they power on the machine, max out its power and measure how high it reaches for a time so small you wouldn’t be able to detect it!

My AV Receiver (JUST the receiver) weighs 12kg. And it’s rated to produce 780 watts of continuous power. The reason I mention the weight is that the stuff that produces power – the transformer – is tremendously heavy and also produces A LOT of heat. If you can put your hand on top of your HTIB’s amplifier during its duties and not get burnt, then…. it’s not that powerful. Ask your neighbourhood engineer about the correlation between power production and heat.

Another shortcoming. Most HTIBs come with what’s called a passive subwoofer. This is a subwoofer that connects using normal speaker wire. It’s called passive because it receives its power from the amplifier in the HTIB. Go back and see again how ridiculous the HTIB power specification.

AV Receivers only work with active (independently powered) subwoofers. The obvious advantage is that the amplifier can power the speakers without having to offload a large amount of power to the subwoofer. And, trust me; producing LFE (Low Frequency Effects) takes a lot of power. Most HTiBs overcome this problem by making the subwoofers unnaturally loud and boomy, which unfortunately we’ve come to think is “real bass”.

The effect of true bass (LFE) is felt in how it compresses air more than its audibility. Even low volume LFE compresses the air. If you’ve been to an outdoor music concert and felt the “bass pumping” and seeming to compress your chest, that’s LFE, compressing the air and pushing it out towards you.

I have a confession here. I lived in an apartment some years back, and had a neighbour who got a new car and started parking it in my slot just outside my sitting room. I noticed that his car had a very sensitive alarm, so sensitive that any small trembling near it would cause it to go off. So I turned up the volume on my subwoofer (a 300-watt, 21kg monster from SVS pictured below) and watched the movie Inception. Most of the bass in Inception is on the threshold of audibility but it shakes the windows. His alarm was going off every 2 minutes.

2 days later he was parking somewhere else.

What does the AV Receiver look like?

Most AV Receivers look pretty much the same with a few exceptions. Most will have a display on the front to show you what input you’ve selected, or the FM channel being played, etc. Then they’ll have selectors for the input, and a volume knob.

As you can see above, there are multiple inputs – HDMI, composite (red-green-blue) or component (red-white – what we call “bananas” in Uganda). Then there are multiple ports for output – also via HDMI, composite or component (for older display devices).

Then there are the speaker outputs. The receiver shown above was one of the top-of-the-line receivers for over ten years – the Denon 4520. This receiver can power up to 11 independent speakers and 2 subwoofers – what’s called an 11.2 configuration.

Crazy right?

I’m yet to meet the wife who will allow her husband to put 11 speakers and 2 subwoofers in the house. But I’m sure that perfect woman exists out there.

This is how you put 11 speakers in a room:

Pretty isn’t it?

And don’t even start me on modern Dolby Atmos setups, where you have 4 speakers in the ceiling!

Anyway, most people, will use the standard 5.1 layout. This gives you the easiest, most immersive solution to your Home Cinema needs.

Most modern AV receivers are built much simpler to support this layout:

Advanced Use

Here are some of the standard features of AV Receivers that make them a worthwhile upgrade.

Automatic Room Calibration

This is the killer feature of the best AV Receivers. Very few of us have a dedicated theatre room. Instead we use a more general purpose room that produces problems. Elementary physics tells us that sound moves as a wave and can be reflected, absorbed or diffracted. So your beautiful living room has hard surfaces (like tables and chairs) that reflect sound; soft surfaces like curtains and carpets that absorb sound; and surfaces like lamps that diffract sound. What this means is that the sound that reaches your ears has been distorted by the room you are in.

AV Receivers have room calibration systems that use a microphone to measure the quality of the sound at different points in your room. Then it uses advanced equalization to help eliminate the effect of the room on the sound.

Multi-Zone Capabilities

The Denon 4520 system highlighted previously can power speakers in 4 Zones although 2 Zones is the standard for most mid-level receivers. This means that (if you have enough speakers) you can have independent sound in up to 4 places. So you can have your CD player playing music to your bedroom, FM Radio in the sitting room, your iPhone using AirPlay to the outside speakers in your compound and a classical music CD to your child’s bedroom all at the same time.

Or if you have a house party, you can send the same signal to all zones at once, or keep the child on Beethoven for the sake of their brain development!

Upgrade-ability

The separation of amplifier, components and speakers means you can make step-by-step upgrades. From a better subwoofer, to beefier speakers, to a Blu-ray player, and so on.

Connectivity

The Denon 4520 pictured above has 7 HDMI inputs, 4 composite, and 3 component inputs. That’s 14 possible devices you can connect!

Coming back down to earth, the other pictured Denon – the E200 – has 3 HDMI inputs, and 2 composite. 5 inputs cover most people’s needs.

Disadvantages

The first disadvantage is that it’s yet another big black box to put in your living space. Then, it will necessitate you getting separate components – speakers and a subwoofer so there are cost implications!

Oh, and your power bill will definitely go up when you’re blasting Jason Statham’s latest movie for your friends.

In Conclusion

If you want to take the next step in setting up a decent home cinema, then you have to go with an AV Receiver. It will give you the most flexibility for upgrading and connecting devices, as well as true powerful output for your sound.

If you’re sensitive to sound quality, you’ll immediately notice the improvement – with the caveat that the quality of your speakers is more important than the quality of the AV Receiver.