Low impedance speakers need a powerful amp, making them a headache to match with a modern AV receiver. But wait! Do not throw them out the window just yet! Here are some of the best value surround sound receivers on the market today, that officially support 4 ohm speakers.

HOME AUDIO Some time ago, my basic, yet trusty old AV receiver started giving me problems with an annoying buzz/distortion in one of the front speakers, but over certain frequencies. This I can say for certain, trying 3 different sets of speaker cables delivering the same sonic imperfection. Then, switching the cables from the buzzing speaker to the other front speaker, only made that other speaker buzz instead. Ergo, I narrowed it down to the amp itself. In this case, my 8 year old 6.1 surround receiver.

Impedance (Ohm) matching

Looking for a replacement unit, I had a significant problem with my current 5.1 speaker setup. Unlike stereo amplifiers, a surround receiver has a lot more speakers to provide power to. Hence, the load per channel which they can deliver is typically more limited. Subsequently, a multi-channel amp tends to require more power-efficient (high impedance) speakers in order to have a fair workload that it can drive safely without the risk of overheating in the process. 

Along with my front line of 8 ohm floor standing speakers, alongside a centre and an active subwoofer, I have a pair of low-efficiency 4 ohm bookshelf speakers playing in the back line. Most (but not all) AV receivers on the consumer market tend to work in the 6~16 ohm range, and a separate amp is often recommended for driving speakers of lower impedance, to avoid overheating the receiver.

Low impedance amp, or high impedance speakers => freedom of choice

Even though there are plenty of 6 and 8 ohm speakers out there to chose from, having a low impedance amplifier gives you more options, in being able to power any speaker that is rated the same, or higher impedance. So a low impedance amp offers you a great advantage in your speaker matching. The same goes when buying speakers. Choosing high-impedance speakers gives you a wider choice of amps and receivers capable of driving them.

The AVR's that do and don't support 4 ohm speakers

Although a nominal impedance of 6 ohms or higher would be advised for buying new speakers intended for a surround system, there's luckily still hope even for your good old 4 ohm'ers. While 6 ohms and up seems to be the industry standard for AV receivers of today, there are exceptions. Check the list below for some model recommendations.

Recommended 4 ohm AVR's

Onkyo TX-NR616
Onkyo TX-NR616
Yamaha RX-V773$799£529
Yamaha RX-V673
Yamaha RX-V673
(titanium silver)
Pioneer VSX-S500
(220V/Europe only)

These are guaranteed to work

Listed right above are some popular AV receivers that officially support 4 ohm speakers. I have them appearing in the order I would personally suggest checking them out, giving you the best bang for your buck. Choice of colour is strictly a personal preference, of course. But for what it's worth, my silver TX-NR616 looks very stylish and classy indeed!

Onkyo and Yamaha usually safe bets...

AVR's from Onkyo and Yamaha are generally rated for a speaker impedance of 4 ohms and higher, which guarantees a safe amplification at any volume. Popular 4 ohm capable models include the Onkyo TX-NR616 and Yamaha RX-V773 of last year, which are both excellent value. If you can find the outgoing RX-V771 model from Yamaha, you might make a real killer deal also -- if you can live without 4k video resolution support and Apple Airplay, that is. If not, the newer RX-V673 is a good choice also. Even earlier models from both Onkyo and Yamaha of course can be found for less, but may lack some more or less crucial features, and it's all down to what your needs are specifically. Older units typically have fewer (if any) HDMI ports, and might not support modern lossless audio formats, like DTS HD and Dolby Digital HD - both of which are commonly seen (or heard, rather) on Blu-ray movies, especially. If you need a lot of HDMI ports, the Onkyos are great, providing as much as 8 inputs and dual outs, already at quite an affordable price point. Other brands offer this as well, but you'll have to go up a few notches to their higher-end models, which may or may not offer the best value for you specifically.

Pioneer also has a few slimline models for the European market, including the VSX-S300 and its newer replacement VSX-S500, which also both officially support 4 ohm speakers. Their already quite limited power resources may not make them the ideal choice for driving power hungry speakers, however.

...While these may not be

Brands like Denon, Marantz and Pioneer are otherwise typically specified for 6 ohms and above, but can typically feed 4 ohm speakers at a lower volume. However, it's important to keep an eye on the working temperature, making sure it's at a reasonable level.

General tip: Don't choke your amp

Excessive heat can of course eventually damage any piece of electronics, and amps and receivers are especially power hungry. Therefore it should be quite obvious that they need some fresh air to breath, but still, ever so often you see AVR's crammed into air-tight TV furniture and other badly ventilated spaces. Or even worse -- people stacking their DVD and BD player on top of the receiver, thus covering up all ventilation. Needless to say, but this is never a good idea, regardless what type of speakers it happens to be driving; if they're 4, 8 or even 16 ohms.

An AV receiver that officially supports 4 ohm impedance is the highly popular, and critically acclaimed alike, Onkyo TX-NR616. That's the model I decided to go out and buy. Check out my review of that AV receiver in my next entry!

See also