Bluetooth 4.0 Vs 5.0 Sound Quality

Bluetooth drives wireless headphones and portable speakers and lets you wirelessly connect your stereo system or soundbar to your smartphone and its myriad streaming services. Yet despite Bluetooth'southward ubiquity, it'south still the virtually misunderstood audio engineering science. Audio companies offer numerous variants—or codecs—of Bluetooth, and some people claim that a sure codec will better Bluetooth sound quality. But those differences are hard to quantify and harder to hear. Read on if you're confused about how (or if) dissimilar Bluetooth codecs should gene into your headphone or speaker pick.

One important affair to note right from the start is that the Bluetooth sound technology you're hearing has a much smaller effect on sound quality than the design of the device itself. If you attempt different wireless headphones or speakers, you'll hear obvious differences. If you endeavour different Bluetooth codecs, the divergence will be modest and perchance inaudible. (You can test this yourself using my online Bluetooth blind test.)

In other words, y'all should cull Bluetooth headphones or speakers based on their fundamental sound quality—equally reported in reviews or as you've adamant yourself—and not based primarily or even secondarily on the Bluetooth audio technologies they support. The codecs don't make a big difference.

Bluetooth audio codecs explained

In sound devices, the key difference in Bluetooth implementation involves which audio codec they employ. A codec (short for "compression/decompression") is a complex algorithm that processes audio information to make information technology smaller and so it's easier to send over the Internet or wirelessly from your phone to your headphones. You've probably heard of some popular codecs used today, including SBC, AAC, aptX, and MP3. Using a codec is necessary because the less data Bluetooth needs to transmit, the more reliable the connection is—and the less likely your headphones are to lose the betoken in the middle of Billie Eilish's "Bad Guy."

These codecs are called "lossy" because they discard almost of the audio data. Typically, they reduce the i,411-kilobits-per-2d data rate of CD-quality sound to effectually 300 kbps. The discarded data represents audio that the human being ear is less likely to observe, such as a soft sound in the presence of a similar but louder sound. Some codecs permit higher data rates, thus requiring less compression and offering the potential for better sound.

Many people believe that transmitting an audio signal via Bluetooth will ever degrade sound quality, but that's non necessarily true. If an sound indicate is already compressed in a sure codec, and the source device (such as your phone, tablet, or computer) and the "sink" device (such as a wireless speaker or headphones) both support that codec, Bluetooth transmits the encoded sound unaltered, and so the audio is the aforementioned every bit yous'd get without Bluetooth. The well-nigh common example is with Apple Music, which uses AAC, and iPhones, which support AAC. If you utilise these two things forth with a wireless speaker or headphones that besides back up AAC, Bluetooth volition not impact the sound quality. If at to the lowest degree 1 of the devices doesn't support AAC, the AAC data is decompressed and then recompressed with some other codec, such as SBC. This process can reduce sound quality, although the divergence will probably be subtle.

A few codecs claim "high resolution" because they tin handle data at resolutions higher than the CD standard, which is sixteen bits at a sample charge per unit of 44.1 kilohertz. However, we consider high-resolution back up to exist more a marketing claim than a useful characteristic here. It would do good you lot only with high-resolution files from a loftier-resolution streaming or download service, and only if your headphones or speaker can reproduce the claimed extra fidelity—and when the codec is discarding so much information anyway, the benefit of giving it even more information to throw out is questionable.

Some other characteristic that distinguishes codecs is latency. The time information technology takes for a digital signal processor to decode the encoded audio is often sufficient to delay the sound to the point where it creates lip-sync problems when you're watching video. Some codecs, such every bit aptX, are less math- and memory-intensive and thus accept less latency. More math- and memory-intensive codecs, such as AAC, may have greater latency but may be more efficient at conserving data and thus may produce better sound quality for a given data rate. At that place are always trade-offs with codecs.

(Here I should disembalm that I worked as marketing manager for Dolby Laboratories from 2000 to 2002 and was involved in promoting AAC, but I have had no financial interest in the company or the technology since I left.)

Bluetooth also comes in different versions, such equally 4.1, 5.0, and five.one, merely these generally accost information-transfer issues and rarely affect audio quality. The only exception I can think of is that newer versions might make transmission a bit more reliable, which could conceivably allow a scalable codec such as aptX Adaptive or LDAC to run at a higher information rate.

Bluetooth sound codecs compared

Here are the audio codecs found in Bluetooth devices. To activate these codecs, you may have to get into your phone'south sound settings. In Android phones, you can typically discover codec selection in the Developer Options menu.

SBC: You lot can notice SBC in all Bluetooth devices. If your source and sink devices can't both support another codec, the connectedness defaults to SBC. This codec can run at data rates as high as 345 kilobits per second. If the source and sink devices can both procedure the audio at a high data rate, the sound quality is hard to distinguish from that of AAC or standard aptX. I've measured its latency at around 200 milliseconds, and as much equally 300 ms with true wireless earphones—enough to create the potential for lip-sync problems when y'all're watching video.

MP3: The familiar MP3 codec is rarely used in Bluetooth, but it is found in a few Bluetooth devices. Technically, information technology falls roughly between SBC and AAC in audio quality, although the departure is tiny or ephemeral. All the same, if your phone and your headphones or wireless speaker back up MP3, it tin can yield a modest reward in audio quality with MP3 downloads or streaming services (such every bit some Internet radio stations) that employ MP3.

AAC: Basically a more advanced version of MP3, AAC more often than not offers slightly better sound at a given data rate than MP3 and SBC do. With Bluetooth, AAC runs at a maximum of 250 kbps, and though I haven't yet had a chance to measure its latency, it's likely at least equally bad as SBC's because AAC's avant-garde coding techniques demand more processing time. If you have an iPhone or iPad, having AAC in your headphones or wireless speaker can be a mild advantage for the reasons explained above. Nonetheless, unlike the aptX codecs, AAC implementation isn't policed by a single company, and as a event it may be inconsistent in Android phones.

aptX: This codec, offered in Qualcomm Bluetooth chips, differs from most others. Rather than encoding a specific level for each audio sample, it encodes the divergence in level between one audio sample and the next. This approach allows it to run faster and accomplish lower latency. My measurements show that its latency is typically effectually 120 ms, which reduces the possibility of lip-sync error compared with SBC. Unlike SBC, which may run below its maximum data rate, the data rate for aptX is always 352 kbps, so there's a certain guarantee of quality, but any aural departure betwixt aptX and SBC is typically small-scale or ephemeral. aptX has never been available in Apple devices, but it is included in many Android devices.

aptX HD: This is a high-bandwidth version of aptX that runs at a information charge per unit of 576 kbps, and every bit yous may notice if you take my Bluetooth blind exam, the difference can be appreciable. With high-quality headphones that can reveal this divergence, plus an Android telephone that supports the codec, aptX HD is nice to accept. I oasis't had a adventure to measure out aptX Hd'south latency, merely it's scalable depending on the application.

aptX Low Latency: With aptX LL, my measurements evidence latency below 40 ms, which eliminates the possibility of lip-sync errors caused by the codec. This codec became widely available merely a year ago and nonetheless isn't available in many sound devices. We hope to see information technology piece of work its manner into TVs, where it would provide an obvious benefit. It would likewise be not bad for tablets, but we probable won't come across information technology in iPads because (like the other variants of aptX) it'south not available in Apple devices. Like standard aptX, information technology runs at a stock-still information rate of 352 kbps.

aptX Adaptive: This new codec should showtime making its way into products in 2020. It promises to automatically conform its functioning for the all-time blend of audio quality, low latency, and reliable transmission. Its data rates run between 280 and 420 kbps, and its latency is said to run between 50 and 80 ms.

LDAC: Sony's LDAC offers the potential for the best possible Bluetooth sound quality. It runs at 330, 660, or 990 kbps; your phone may allow you prioritize sound quality (990 kbps) or connexion reliability (330 kbps). LDAC is bachelor on many Android phones, but not in Apple devices. I have yet to evaluate its latency, and Sony doesn't publish a spec. I've seen claims that, because LDAC is a sort of hybrid of the technologies used in aptX and conventional codecs such as AAC and MP3, information technology offers relatively low latency, but I haven't found whatever substantiation of those claims.

LC3: Also called Low Complication Communications Codec, LC3 is part of the new Bluetooth LE Audio standard introduced at the CES 2020 trade show. It is said to accomplish higher sound quality than SBC, or comparable quality at lower power, which would extend battery life. Products using LE Audio are expected to emerge in late 2021 or 2022.

Again, the differences in sound quality among these codecs are subtle at best. This is why we don't make the inclusion of certain codecs a major factor in evaluating Bluetooth headphones and speakers. The acoustical tuning of the speaker or headphone drivers and enclosure, and the tuning of the device's digital signal processor, have an exponentially greater effect on audio quality—and your twenty-four hours-to-day enjoyment of your audio gear—than the Bluetooth codec does.