Wireless Speakers for Surround Sound? Don’t Ask, it’s a Mess
We see the question on home theater forums quite frequently – someone wanting wireless surround speakers because they can’t run the wiring for some reason. Unfortunately, at this point in time there are no quick and easy answers. “Wireless surround” rolls off the tongue easily, but the problems actually achieving it are myriad.
Spotty Reliability: Good Money after Bad
I’m sure the AVR manufacturers would love to deliver wireless capability for surround sound speakers, but Bluetooth, which uses the crowded 2.4 GHz band, is unreliable. This means you can have interference or even drop-outs caused by other devices in your house, or maybe even your neighbor’s house, if it’s close enough to you.
As far as I can see, with only a few exceptions, wireless 5.1 soundbars mostly populate the low end of the product category. That should tell you something right there. If it doesn’t, just pick one and look at the Amazon reviews. Few of them can muster more than a 40-60% approval rating (combined 5- and 4-star reviews). If that doesn’t tell you enough, dig into the negative reviews and you’ll find that probably half of the complaints are wireless issues. Even with 2.1 soundbars with wireless subs, it’s the subs that get most of the criticism in the negative reviews.
People buying lower-end soundbars are not audiophiles by any stretch and won’t get up in arms too much if their wireless 5.1 system is blinky, especially since it didn’t cost that much to begin with.
However, what are the chances that people shelling out $500-$1000+ will put up with anything less than perfect performance from a “wireless” AVR? Close to zero, it’s safe to assume. The manufacturers would be crazy to open themselves up those kinds of complaints and bashing on forums like this and have their good reputations trashed. They aren’t idiots. That is most likely why manufacturers like Denon (HEOS) and Yamaha (MusicCast) currently limit wireless speaker capability to less-demanding multi-room applications (and their wireless speakers can't generate any better user ratings than the cheap 5.1 wireless soundbars). (UPDATE: Yamaha has bravely taken the plunge into the wireless surround game – see below.)
If the pro audio field or even Sonos is any indication, reliable wireless technology is not cheap. Just check the prices of Shure, Audio Technica, Sennheiser et.al. wireless mics or personal monitor systems. Or the better wireless headphones from companies like Sennheiser that get high user approval on Amazon. It’s easy to see that an AVR with rock-solid wireless stability will carry at minimum a $150-200 premium to do the rear speakers wireless – per channel. That means at least an additional $300 for a 5.1 channel AVR or $600 for a 7.1. Does anyone want to venture into the land of 9.1 or 11.1? How many people are willing to pay for this?
Mystery Specs: The Audio Equivalent of a Blind Date
Even if you get past the delivery system, there are other issues with wireless speakers for surround sound that audiophiles won’t take kindly to. For instance, Bluetooth speakers are commonly battery powered. That presents at least a couple of problems. For one, how do you like the prospect of the batteries giving up on you in the middle of a movie?
Then there is the power issue. It’s basic audio physics: Watts require voltage and/or current. How many watts do you think a battery-powered speaker can generate? So, your receiver has 100 watts for the front channels, but your wunderkind wireless rear speakers maybe get 10 watts.
Naturally, you can get speakers that run on electricity, but of course you no longer have wireless speakers, do you, if you have to run power cables to an outlet somewhere?
Then we have another glaring issue: Just try to find a wireless speaker system, Bluetoothor otherwise, with standard audiophile specifications like frequency response, S/N ratio, or THD. Not even the highly-regarded Sonos publishes that stuff. At least Rocketfish is brave enough to put out specs for their wireless transmitter / receiver / amplifier system, even if they are pretty pitiful: S/N a mere 87 dB (no weighting qualification), and 30 watts x 2 @ < 10% THD (no frequency-bandwidth qualifier).
Another problem that’s sure to grate on audiophiles’ sensibilities is the lack of free interchangeability of the equipment. For instance, it’s easy to observe that all current wireless offerings, be they 5.1 soundbars, or Sonos, Denon HEOS, et. al. are proprietary integrated systems. You get what they come with, and that’s it. What happens if you want to upgrade the wireless surround speakers? You can’t say, “The rear speakers for this Vizio soundbar reek, so I’m going with JBL instead.” No such luck. You have only one option: The speakers that came with the system.
Wireless Hope Springs Eternal
Despite all the obstacles and shortcomings, at least one category of wireless speaker does get consistently good user reviews: Wireless subs from companies like Klipsch. However, subs are able to get a significant pass on the audio specifications issue, since mediocre S/N, THD and broadband frequency response are not terribly relevant.
But when you think about it, wireless subs really are the exact same thing as a system like Rocketfish, complete with a stand-alone transmitter at the AVR end, and a receiver with outboard amplifier and speakers at the other end.
That should be sufficient to show that there is no way around it: If you want wireless surrounds, at this time a stand-alone transmitter / receiver system with an outboard amplifier and speakers is the best bet. For most people, the main issue is merely getting the signal to the back of the room. It should be a minor inconvenience from that point finding a place to locate the amplifier and run wires to the speakers. For that trouble you get the most flexibility in equipment options – as much or as little as you want to spend on the amplifier and speakers.
Wireless Options: The Good, the Bad...
The cheapest wireless option is a Bluetooth transmitter / receiver system, but they come with the problems typical of stand-alone Bluetooth speakers – mystery audio specs and spotty wireless reliability, although the Avantree Oasis seems to be better than most in the reliability department, and JL Audio actually publishes audio specs for their pricey Jlink TRX.
Bluetooth’s aptX codec can placate the dearth of audio specifications to a certain extent, but Bluetooth also has another big red flag, in that it’s a digital platform. This means a transmitter also does analog to digital conversion, and back again on the receiver end. That’s just more “stuff” in the signal chain, not to mention one more thing you’re taking a chance on – the quality of the converters.
Undeniably, the best options in transmitter / receiver systems currently come from the pro audio field (and I expect will for many years to come), where they’ve been doing wireless for over three decades and have it down to a science. They aren’t cheap, but they promise the best wireless stability and sound quality. As an added bonus, the manufacturers publish meaningful audio specifications. However as we’ll see, even this option is not without issues.
A prime contender suitable for a home theater application, as well as currently the most economical professional option, is the DN-202WT transmitter and DN-202WR receiver combo from Denon Professional. Although this system is based in the crowded (and therefore potentially problematic) consumer 2.4 GHz band, it utilizes Channel 25 of the IEEE 802.15.4 standard to minimize interference with Bluetooth and wi-fi devices, which should make it more stable. (Note: This system should not be confused with Denon’s DN-200 system, which is Bluetooth-based.)
Another pro audio-based solution is the Alto Stealth system. It’s a good bit pricier than the Denon, but it should be significantly more reliable because (like most other pro audio wireless equipment), it operates in the UHF frequency range, not 2.4 GHz. Another feature the Alto system has is 16 user selectable channels. This greatly enhances the possibility of reliability reliable performance. An added bonus is that it’s an analog system, so A/D conversion is not an issue. An analog system with enhanced stability afforded by numerous operating channels should make it an attractive contender to audio enthusiasts.
If you do your research on either the Denon or Alto systems, you’ll find there are indeed reliability complaints relating to wireless delivery. But keep in mind that most users are working in a professional capacity of some sort, be it live performance or a permanent installation. As such, line-of-site and long-range complaints can probably be ignored in a typical home environment, given the relatively short distances involved.
However, depending on where you live, a possible issue with a budget system like the Alto is the relatively small number of channel options. If you live on a farm in rural Minnesota, you’ll be fine. But if you live in a crowded UHF locality like Manhattan or any other major city, you might have a problem finding a “clean” channel that doesn’t get interference.
... and the Expensive
The Alto system is a variation of a product commonplace in pro audio these days: a personal monitor system, otherwise known as in-ear monitors. Such systems are the next step up the “food chain” if the previously mentioned options fail to deliver wireless stability. If you’ve seen any performances on TV where the singers or musicians appear to be using earbuds, you’ve seen a wireless in-ear monitor system in action. It basically allows the musician to hear himself and the other performers on the stage. Where in years past a mixing console sent the monitor signal to amplifiers and then to speakers on the stage (angled up at the musicians), now the signal is sent to wireless transmitters.
As you can imagine, with multiple performers on a stage using wireless systems for their mics, instruments and in-ear monitor systems – all at the same time – wireless stability is a drop-dead requirement in this environment. Anything less is fatal, as drop-outs, crosstalk, picket-fencing or all-out RF white noise roar can trash a performance in front of thousands of people (or even millions, if on TV). Thus any quality personal monitor system would be a significant step up in stability from the alternatives previously discussed.
The receiver of a personal monitor system is a “body pack” the performer clips to his belt or pocket that has a headphone jack. As such, it would be a cinch to use a simple adapter cable to get the signal from the wireless receiver to the inputs of an outboard stereo amplifier for rear surround speakers.
Monitor systems can be had in a wide range of prices, but at this point it should be glaringly obvious that the cheaper the price of a wireless system, the more trouble-prone it is, and as such bottom-of-the-line products may not work any better than the options previously discussed.
A prime example is the Galaxy Audio AS-900 system. It features 12 user selectable channel options, decent audio specs (as long as you can live with extension limited to 80 Hz), and can be had for as little as $200. However, its Amazon user ratings (combined 5 and 4 star reviews) are no better than the cheap wireless soundbar options, with the #1 complaint being – wanna guess?
Meet the Lamborghini of Wireless Options
Decent name-brand personal monitor systems from Shure or Sennheiser (which seem to be the heavy-hitters in this field) that would be a significant step up from Galaxy or Alto in frequency response and/or number of channel options will probably start at $6-700, and can go to up to $5000 or more. At this point “significant step up” can mean diversity tuning, but largely means available channel options, as these systems have significantly more than even the Galaxy. For example, the Sennheiser systems have over 1600 tunable frequencies. The ability to find a suitable frequency to operate on is a key factor to the stability of these systems. In addition, some even do automatic scanning to search for a “clean” channel.
A price-conscious option if you find you must use a personal monitor system for your wireless surround set-up would be a used system. One that’s a couple generations old (or more) might not be “the bomb” if you’re a working musician, but it would work just fine in the home environment.
The big downside to the personal monitor system alternative is that the belt-pack receivers are battery powered, so obviously a wall-powered option is needed. It wouldn’t be hard for an enterprising person to rig up a wall-wart to power it, although the modification may void the warranty. As an alternative, a company called Agiprodj claims to offer a powered option for Sennheiser receivers that should work with other brands using AA batteries.
The Lamborghini Elephant?
Even with the “Lamborghini” options, there is another significant issue with wireless that can’t be overlooked. The elephant in the room is the potential for background noise.
Looking at the specs of various wireless products, it appears that no manufacturer, no matter how expensive the product, gives an unweighted specification for signal-to-noise (S/N) ratio. Most don’t offer any weighting qualifiers in their specs, which tells me they are probably A-weighted figures.
Why does this matter? An unweighted S/N specification (aka Z weighted, typically given as dBu) is broadband, while an A-weighted spec rolls out the upper and lower frequencies, which is typically where noise is audible as hum or hiss. Actual noise from an A-weighted noise spec can be up to 10 dB worse than that from a more honest dBu spec. I won’t go into great detail here, but you can find more about the deficiencies of A-weighted specifications in Part 8 of my epic gain structure article. (If you’re unfamiliar with this topic, I recommend taking the time to read it.) Suffice it to say, if you’ve ever seen an audio product with an outrageously high S/N spec of say, 112 dB or more, you can rest assured it is most likely an A-weighted figure.
So, what kind of noise specs do we get with wireless products? I already mentioned that Rocketfish publishes a less-than-spectacular S/N spec of 87 dB with no weighting qualification (translation: A-weighted). The budget Amphony Ifinity transmitter / receiver system is rated at 91 dBa (I’ll give them kudos for at least giving us the “A” qualifier). JL Audio specs their pricey JLink TRX at a mere 80 dB @ 1 kHz (translation: worse than A-weighted!).
Things don’t get much better when we move over to the pro audio gear. The budget-friendly Denon 202 system specs at 90 dB. Even in the “Lamborghini” department, the personal monitor systems from Shure and Sennheiser also top out at 90 dB, even their mega-buck, top-of-the-line offerings that cost over $1000. All with no weighting qualifier, so we can assume they are A-weighted figures as well.
Alto does spec their Stealth system at < 100 dBa, which I personally find highly suspect (yes, they actually say “dBa” so kudos for that). If Shure and Sennheiser can’t get better than 90 dB with systems that cost $700+, are we supposed to believe Alto can best them at half the price?
Bottom line, no wireless system, even an expensive one, will be as quiet as a wired system.
Now, all this may matter little to most people using passive speakers with sensitivity ratings in the mid-80s. I’ve owned receivers that had some audible noise with the volume all the way up and ear to the speaker that worked just fine in regular use. But if you have a custom active system and / or highly efficient speakers, you could run into problems with wireless noise. (In Part 4 of my gain structure article you can find a link to a case study at AVS Forum for noisy electronics with a custom active system.) For example, I find it illuminating that Klipsch, builder of efficient speakers with sensitivity ratings in the mid-90s and higher, does not even publish noise specs for their wireless RP series.
What about WiSA?
Creating some buzz in the industry is a new wireless protocol for home applications called WiSA. Okay, it’s not all that new – the Wireless Speaker and Audio Association has been around since 2012. Despite an advisory committee of 60 companies – many familiar to audio enthusiasts, but some not even in the audio business – only a handful of companies have released any WiSA-compliant products to date. Klipsch and Bang & Olufsen are two notable participants with products on the market. The WiSA platform once again confirms that any viable wireless system will require outboard transmitters, receivers and amplifiers. However, in this case the receivers and amplifiers are integrated into active (powered) speakers.
Some, perhaps many, audiophiles are duly excited by what WiSA could potentially offer for advances in sound quality. As AV NIRVANA’s own tech guru Matthew Poes explains, WiSA’s promise of flawless wireless stability “is a compelling feature that opens the door to other great advantages. For instance, every speaker could be bi-or tri-amplified with active crossovers and even fully customized EQ, in addition to the excellent channel separation that currently only wired monoblock systems can deliver. There is no impetus for most manufacturers to move in this direction without wireless.”
WiSA claims the ability to stream 7.1 channels of high-definition audio with no compression or loss of fidelity, but it’s difficult to find any audio specifications on the platform to verify its claims. As of this writing, there are none on WiSA’s official website, and none from independently-verified sources that I can find on the web. No manufacturer of stand-alone WiSA transmitters publishes any audio specs either. Broadband frequency response, THD, signal-to-noise ratio, channel separation – it’s all a big mystery, as is the case with so many cheap Bluetooth systems.
The wireless delivery system seems impressive, though. According to Audioholics, WiSA operates on 24 tunable frequencies in the 5.2–5.8 GHz range. These channels were originally reserved for weather and military uses, and consumer devices are only allowed to use these important channels as long as there is no interference. A WiSA-certified system constantly monitors for interference and instantly jumps to a new channel if any is detected, and does so seamlessly with no audible dropouts.
How well does it work? A company called Enclave Audio sells a WiSA-certified 5.1 home theater system, the cheapest of the few such products currently on the market. Amazon user reviews show a lackluster 70% approval rating (combined 5- and 4-star reviews). It also has a significant number of 1-star reviews – well over 10% – and a good number of them mention wireless issues. So it seems the lower-end WiSa offerings are only marginally better than the Bluetooth-based systems. And wading through this thread from AVS Forum also confirms that WiSA is not without its issues.
But as you can imagine, WiSA’s sophisticated technology does not come cheap. It’s hard to fully get a handle on the price WiSA compatibity would add to an audio system, since there are limited products on the market. Stand-alone transmitters are few to be found, and range in price from $400 to over $1000. So that’s a pretty big expense added to an existing system.
But – on the receiving end things get interesting. One of the few speakers listed on the WiSA website is the Klipsch RP-140WM, which has a 4.5” woofer and 1” titanium tweeter, and sells for $599 a pair. The closest comparable regular speaker from the Reference line is the RP-150M, which has a larger 5.25” woofer and 1” titanium tweeter, and sells for $419 a pair. The $183 difference constitutes a 44% markup. On the surface that seems like a lot, but when you consider that you’re getting two WiSA receivers and the equivalent of a stereo amplifier for $183, it doesn’t seem like a bad deal at all.
But the bad news, however, is that there are no WiSA options if all you want is to get a wireless signal to a pair of rear speakers. As we shall see, WiSA is an “all or nothing” proposition.
Reinventing the Home Theater Wheel?
Anyone seriously considering a WiSA setup may want to entirely re-evaluate their system requirements. For instance, since the speakers are active, a traditional multichannel home theater receiver is not needed. Indeed, you don’t even need an A/V preamp-processor.
With a WiSA system, you plug all your source components into something like the Axiim Media Center hub, which sends a video signal to your TV via HDMI, and wireless audio to your full complement of active WiSA speakers. As mentioned, the speakers’ built-in amplifiers are economical – less than $100 per speaker. So theoretically, with $1200 for the Hub and $100 per amplifier channel, you could have a basic 5.1 or 7.1 WiSA surround sound system for about the price of traditional AVR receiver in the $1800-2000 range, plus the cost of what otherwise would be traditional wired speakers.
However, you will likely be limited to ground-level placement. That’s right, no hanging these speakers on the wall or putting them up on shelves, unless you want to look at dangling power cords or do some custom electrical work to get outlets up behind the speakers.
And it should be noted that neither Klipsch, Axiim nor Bang & Olufsen publish noise specs for their WiSA offerings (they’re in good company, as no other WiSA vendor does either). Needless to say, I’m not as optimistic about the platform as my colleague Matthew Poes.
WiSA: Dead on Arrival?
But ultimately none of this probably matters. As of this writing you can count the number of WiSA vendors on two hands with fingers left over, which is a pretty sad showing considering how many years it’s been around. Thus WiSA essentially appears to be dead in the water.
Why? It wouldn’t be hard to argue that WiSA is an ill-conceived concept that offers a solution in search of a problem. Point being, on these forums we virtually never see anyone inquiring about a 100% wireless surround system - i.e. all speakers including the front three. Typically the inquiries are about the back speakers, subwoofers or secondary zones.
Rather than trying to meet a common and worthwhile need for reliable wireless rear surround et al., WiSA aspires instead to re-invent the home theater wheel. But only half-way, as the platform precludes modern features like auto room calibration, second-zone capability, Dolby Atmos and tons of other audio processing formats, not to mention the myriad of streaming services.
So basically, aside from the wireless capability, WiSA was obsolete from Day One. That’s probably why no major audio hardware manufacturer has signed on. Despite the claim of being a consortium of over 60 brands, the majority of the few available home theater products are from brands no one has heard of.
If WiSA wants to make some money, they should come up with a system for wireless rear surround sound or secondary zones that easily connects to a conventional AV receiver. That's what people are most interested in for a home theater application.
In the mean time, most home theater enthusiasts should be able to obtain satisfactory stability with the wireless offerings discussed above from Denon or Alto, with the added benefit of unlimited choice in speakers instead of the scarce options you get with a WiSA-based system.
So there you have it. As you can see, wireless surround sound is not a pretty picture, anyway you cut it. And really, even if you are lucky enough to get away with going the cheapest route (Bluetooth), by the time you spring for a transmitter / receiver rig and a suitable remote amplifier, you could probably hire someone to run wiring to your back speakers. Or, you could save money by doing the wiring yourself.