Is Bluetooth as Good as a Wired Connection?
Back when I visited CanJam NYC in 2016, I got to talking to the two founding members of Bluewave, and had an extended conversation and demo of their soon-to-release Bluetooth receiver/DAC/Amp, the GET. They argued that the quality of Bluetooth has reached a point where the internal components used had a bigger impact on the final sound quality than the fact that it was wireless, and their device would have better sound quality than the headphone jack in my smartphone. I thought this was an interesting challenge, and I had to research and rethink my perspective on Bluetooth audio.
You see, Bluetooth is a digital transmission, so it bypasses capacitance and EMI factors of headphone cables. Then, the Bluetooth receiver must then use a DSP (like a computer) to decode and decompress the transmission, a Digital to Analog Converter (DAC) and an Amplifier before outputting to the headphone transducer (speaker). When you buy a Bluetooth receiver, you’re also buying a DAC and an amp! With a made-for-Audio Bluetooth receiver, all the components inside have the opportunity to be built to higher spec than what is included in a smartphone or laptop.
The current state of Bluetooth audio is different than most people realize, and better than the stigma. There are advantages and disadvantages, besides not having a cord coming from your pocket.
Shortlist of +Pros and -Cons
+High res Bluetooth codecs (aptX HD, LDAC, LHDC) don’t have to re-compress Spotify Premium streams and have little to no compression added to FLAC streams close to CD quality (TIDAL HiFi, Qobuz high res).
+Bluetooth can extend further than most wires included with headphones, and also pass through thin walls without drilling a hole.
+Wires (especially longer wires) can affect the sound reproduction, but Bluetooth is transmitted digitally with error correction, and the BT receiver, DSP, DAC, Amp, and headphone transducer/speaker are either point-to-point soldered together or have very short signal paths.
+The DAC and Amp can also be tailored to match the headphone.
-Latency is reduced but still present.
-While Bluetooth range is pretty long, sometimes it can be blocked by walls or subject to interference when many Bluetooth signals are blasting nearby.
-Bluetooth headsets are limited by battery life, and the source (I.E. your phone) drains battery a little faster than a wired connection.
-A battery and other electronics in a headphone/headset mean more weight and bulk, which is often the reason behind neckbands or short battery life in True Wireless IEMs.
-Bluetooth audio can only be sent to one device, so no silent discos.
Bluetooth 5 and 5.1
Back when the Sony Xperia XZ Premium, iPhone 8/X, and Samsung Galaxy S8 were coming out with Bluetooth 5 in 2017, I got really excited about its increased power that could be used for range or data transmission rate. Figures like 2 Mbit/s burst transmission at short range or lowering the transmission rate to achieve over 300 feet of range boggled my mind, and had me thinking Bluetooth could become an alternative for WiFi in some cases. However, I later learned that those high figures were only possible with two “class 1” Bluetooth devices (both transmitter and receiver), and that in a more practical sense these Bluetooth codecs would mostly affect advertising and “Internet of Things” devices. Bluetooth audio would remain mostly the same as the 4.2 era, with about the same 30 foot range and the audio bitrate determined by the Bluetooth codec.
Want to stream Spotify Premium, Apple Music, or a social service like YouTube and Facebook? Bluetooth that supports AAC or aptX will be enough to transmit the audio without further compression. Want to stream TIDAL or Qobuz Hi Res tiers of service? Qualcomm’s AptX HD, Sony’s LDAC, and Savitech’s LHDC can carry higher bitrates, and at short range in a good environment LDAC and LHDC can “carry” most of a CD-quality FLAC amount of data, but they’ll probably need to compress the data just a little. AptX Low Latency and similar codecs interest me the most for gaming, because lag is always our enemy!
We’re seeing many releases now for Bluetooth. There are the traditional on-ear/over ear headphones, neckband IEMs, what I’ll call neck-wire IEMs, and True Wireless IEMs, as well as Bluetooth Receivers.
On/Over-ear headphones were the first type of Bluetooth Headphones, but these days some manufacturers are beginning to experiment with Hi-Res Bluetooth headphones that are meant for serious listening.
Accessory neckbands that add Bluetooth to existing IEM models or are hardwired to rereleases of earpiece capsules (for example, the IE 80S BT or the CX 7.00bt from Sennheiser) add flexibility, and put the weight of the battery, remote controls, and electronics on your neck instead of hanging on your ear, and they often use the extra space for larger batteries and sometimes dual microphones for noise cancellation. Neckbands are also an easy solution for how to share one Bluetooth connection between the left and right channels. Neck-Wire Bluetooth IEMs, such as the Sennheiser Momentum Free, have an in-line “pod” hanging from the ear with the electronics, a shorter battery life, but they are flexible and easier to fold up into a small pocket-sized case.
True Wireless IEMs deserve their own paragraph here! They may be the newest, hottest thing, but they’re tricky to do well. First thing people realize is the earpiece battery life is shorter than we’re used to, and almost all of these come with a “charging case” that is essentially a battery bank... but I only use IEMs for one or two hours at a time before needing a break, and I recommend thinking about how long a typical IEM session comfortably lasts. These are intended as everyday carry devices, so charging at night or after long-term storage is to be expected. Second, how to sync and share audio between the left and right ear pieces? I’ve had different engineers tell me that basically the best way to go is NFMI, or Near Field Magnetic Induction. Bluetooth has difficulty transmitting through water or dense materials – like our bodies – so magnetic induction is better because it can go through or around the head to keep the earpieces in sync. One earpiece has to be the “Master,” so that’s why usually there’s one earpiece that drains battery faster than the other side. Thirdly, they’re a bit heavier than wired IEMs.
Bluetooth Receiver devices are a new category, and shouldn’t be overlooked. You could also call them a wireless adapter, because what you do is plug regular wired headphones or IEMs into this (usually little) device, and the device does everything from streaming the audio to powering your headphones. That way, if you already have a headphone with a sound you like, you can have your favorite flavor and get it in Wireless too. Some examples from this category are the Bluewave GET, Radsone ES100, FiiO BTR3, iFi XCan, and many more units from companies like Astell and Kern, Creative Labs, Beyerdynamic, etc. There are also a number of Digital Audio Players (DAPs) that also have a 2-way Bluetooth function, so they can also act as wireless adapters in addition to being their own source of audio. Some examples of 2-way Bluetooth DAPs include the newer Sony Walkmans (Walkmen?), Hiby DAPs, FiiO DAPs, Shanling, Cayin, Acoustic Research, and more.
DLNA servers or Airplay over WiFi are still going to be our uncompressed digital wireless solutions for now, and RF Wireless is still going to be the lag-free solution that should appeal most to gamers, though RF options are fewer now than they once were.
Wireless and Gamers
Well, the biggest issue I’ve seen is lag. Bluetooth receivers have work to do before they can playback sound. Furthermore, if Chat with a microphone channel is meant to send audio back to the gaming device, that cuts into the total available bandwidth and only certain audio codecs support an audio return channel. Games like PUBG Mobile switch to audio codecs usually meant for phone calls, which leads to noticeable drops in the game audio quality. That’s why Turtle Beach, Astro, and other gaming headset makers have often made “headset and base” combo units, using RF instead of Bluetooth. Sennheiser’s new GSP 670 and GSP 370 use a USB dongle that acts as an 2.4 GHz RF transmitter instead of using a big base station, and the GSP 670 only has Bluetooth 5 as a secondary transmission option for mobile devices. Lastly, wireless bandwidth, whether Bluetooth or RF, is usually only enough for stereo playback... so if you want a true binaural “Surround Sound” mix, the processing has to be done before transmission, otherwise the two channels of information are only really suitable for emulating two speakers in front of you.
However, I see some hope! Again, AptX LL helps a lot with the latency issue. And I don’t know what codec is supported with Call of Duty Mobile on my iPad, but I have a certain Planar Magnetic Bluetooth Gaming headphone that performs much better in the new game than PUBG, essentially with playable latency and much better audio quality!
Personally, I’ve observed huge advancements in Bluetooth audio over the years. Much of the old stigmas have been addressed, and I’m excited to see where the future takes us.
Bio: I am Evshrug here, Head-Fi, Instagram, Twitter, Twitch, and on YouTube. I got into audio because I wanted a more immersive gaming experience, and I write because I want to help people and share what I learn. Currently, I consult for a few audio companies including Sennheiser and Dekoni, but my statements don’t represent those companies (and their level of knowledge). Learning is always a work in progress, so feel free to add sources and help out :)
A link to all my blog posts: http://www.head-fi.org/t/646786/evshrugs-if-i-knew-then-what-i-know-now-discussion-journal