 We've already made some big investments into our testing lab. A new building, new talent, and some crazy new equipment. And we are finally ready to start talking about it. See these two heads? They're called hats, or head and torso simulators. They're for testing personal audio products, and the ones in front of me cost a combined 80,000 US dollars. Which is why we definitely cannot afford to keep both of them. What? Linus, no! Please, I'll do anything. Anything. Uh... Crucial's DDR5 RAM is engineered to load, transfer, and download files faster with less lag time and more efficiency. Get your Crucial DDR5 RAM today using the link down in the description below. The keen-eyed among you might notice that our hats happen to be missing the torso part. But that's okay, because that only really matters for speaker testing, and we're going to be focused on headphones and microphones for the time being. Also, the torso is a plastic tub that adds 20,000 dollars to the cost, so... I'll pass? Now understandably, you might actually feel the same way about the has part. Couldn't we just use any plastic head? The answer is no. There is a method to the madness here. This form of hearing simulator was first created in the 1980s to accommodate the testing of phones and hearing aids. You see, the thing about hearing devices is that depending on the conditions, they can perform dramatically differently. You can try this for yourself. Lift your headphones off your ear like this. 🎵 Sounds pretty different, right? So, these state-of-the-art hats models from just a couple of years ago both claim to better represent a headphones real-world performance by simulating not just the shape of a human head, so you get a good seal, but also even the ear canal. Both of them are also equipped with high-performance microphones, allowing us to test the full range of human hearing, with both of them costing about as much as an actual human head. Don't ask me how I know. So why not just hire trusted listeners to evaluate headphones for us? It's because listening is a subjective experience that can be influenced by your mood, your biases, and even your... Um... State of mind, man. That means that any product review that relies solely on a human evaluator will be inherently unreliable. Now, we could look at the spec sheet, but a shocking number of audio manufacturers seem to be pretty much copy-pasting the same performance numbers alongside beg-posting nonsense like next-level listening or we retain the emotion of the sound. Emotion! So, I guess we can't trust them either. What do? If you've ever read or watched headphone reviews, you might have seen something like this before. It's called a frequency response graph, and it's meant to help us visualize the sound signature of an audio device. The left end of the X-axis represents the lowest bass sounds that humans can hear, about 20 Hz, and the right end represents the highest treble frequencies that humans can hear, around 20,000 Hz. With these, we can chew through manufacturer claims like a hot head chews through butter. Some might claim to have a neutral sound, for example, but actually they have the bass cranked up so high it would wake up your neighbors. To measure these numbers though, we need to start with the right gear. Let's get acquainted with our potential suitors here then. Bachelor number one is the BNK5128 Type B, and aside from having obviously better microphones, it improves upon its 1981 predecessor in a few ways. For the ear canal, BNK averaged MRI scans of 40 test subjects to give it a longer, more human-like shape, and instead of using purely soft rubber, they added plastic components to the inner parts to represent the acoustic effect of the bony inner ear. Now for bachelor number two, sort of. The HMS 2.3 LNHEC, aka the Super HMS, comes from Head Acoustics, and by their own admission, it is actually based on the BNK5128, but simplified. It has a shorter ear canal and is made of just rubber, resulting in slightly looser tolerances for acoustic impedance, both below 80 hertz and above 12 kilohertz. Not ideal, but the larger diaphragm of the Super HMS's microphone results in a lower noise floor, which means slightly improved performance in certain other tests, like distortion. Now there was a bachelor number three right here, but our headphone test engineer has actually worked with that model before and thinks that it is crap, so we didn't even bother renting one. Now at this point, at least on paper, it seems like the 5128 is the obvious choice, but a lot of that is based on manufacturer claims, which is not how our lab is supposed to work. So we spent the last few weeks, which cost us thousands of dollars in rentals, by the way, validating those claims and searching for potential flaws. While looking fabulous, of course, WAN hoodies now in stock, lttstore.com. As for why it took so long to test, I'm really glad you asked. We needed to run two sets of tests, one comparing the heads to each other, head to head, you might say, and the other comparing the heads to 25 of our own fleshy guinea pigs, I mean, excuse me, employees, and that's for a human to machine comparison. Now the demographics of our company are not representative of the general public. Got a lot of default character creation screen dudes here, but after some adjustments to our calculations to compensate, we were ready to measure the base of eight different headphones on each of our human subjects. Why only base? Okay. We wanted to measure treble as well, but because treble sound waves are very short, a 15 kilohertz wave is actually less than an inch, the microphone position needs to be very precise across all of the test subjects, which we didn't have time to deal with during our short-term head loans. Base waves on the other hand are very long, a 20 hertz sound wave is 55 feet in length, so microphone placement doesn't require the same level of precision across our human subjects to acquire comparable results. And besides, in our head to head testing data, we found only small differences in the treble range between the two heads, so we proceeded with our human testing, oh, apparently I'm next, let's go. Step one is our subject gets to place microphones into their ears like how? I don't know how. So the first step would be to sanitize your hands and also sanitize your ears. That makes sense even in not COVID times when you're talking like ear goop. Look at it go. This is for the inside of your ears. Now we have to place the microphones. This is the left ear. Okay, here you do the left one. And then I'll do the right one. Okay, it goes inside your ears like this. It does not necessarily fit everyone. For some, it's a bit too small and it just keeps coming out, something you might be familiar with. This is cool. So microphone right here, right, and then this little guy sits in your ear, a little something like, I guess it goes kind of like that. Okay, and then this goes here. Okay. So then with the headphones on the way you normally would. Okay. Then I'm going to play a noise. Our headphone test engineer just played pink noise to the headphones for me, which you could think of kind of like pink noise is tuned more for human hearing. So it doesn't sound so harsh to us. Now I take them off. I put them back on. Yeah. Every time we put on our headphones, we do it a little differently. Maybe the band is here, or maybe it's more like here, or maybe our kids are playing around with all the adjustments. And that's the second pass. Okay. And we do that five times with every subject. Yes. Now these are open backed headphones. Is it a problem that people are clicking their mouses and stuff? Again, we're not in a controlled lab environment. So that's expected. They will not miss an opportunity to remind me that the current conditions are not perfect. I know. Over 1000 measurements later, the resulting average looked like this. So how does that match up to our heads? The quick and dirty version is that with open back headphones, we found a measurable but minor variance between the two units and between our human test subjects. But both of these are within what we'd consider to be an acceptable range. Our engineer isn't ready for video appearances yet, but he will be publishing a more detailed write-up on Flowplane for those of you who want to dig a little bit deeper into why we consider that okay. Shifting gears to a popular closed back headphone, we see a much different story. Look at this variance in humans at 40 Hertz. 14 decibels. That means that some people would be perceiving more than twice as much bass compared to others, completely changing the listening experience. This is because closed back headphones rely on a proper seal to create their bass. Comparing our heads, however, again, they're pretty close. But the 5128 measured slightly closer to our humans than the Super HMS. So both heads get a pass here, but the 5128, it gets a gold star. We also tested some in-ears that are known to cause problems for hats in general and found that this issue was present in both of our models, meaning that these had struggled to get a good seal on some larger IEMs. Two more passes, but this time with unhappy stickers because it means no matter which way we go, I'll eventually have to replace this darn thing. Really? Anywho, I guess it kind of makes sense that our results have been so close given that both of these models are based on the same design and that both are considered industry standard testing equipment. We do, however, have a winner. The BNK5128. Some may disagree with our assessment. Some might not think it's worthwhile to get any head and torso simulator because the greater body of academic headphone research has been done on older simulators and is therefore less applicable to this new hardware. But we feel that we can take the current knowledge base and adapt it to the newer models to get the best of both worlds, the best research and the best tech. To be clear, the Super HMS is still an excellent product and a major improvement over its predecessor, but the things that pushed us toward the BNK were its ease of use, improved durability and better reputation. I'm happy with our choices, but there's a big but here. I want to make it clear that our results here are not the be-all and end-all of audio testing at all and the testing that we end up doing in the future. With the BNK5128, it's not going to be the be-all and end-all either. For one thing, this simulator by design represents the average person and no one person is average, especially not you. As an LTT viewer, you're decidedly above average. So what that means is that the response curves that we get from this head will not directly reflect what you hear in your ears. It's just that by adding some objective knowledge to your toolkit, you can become a more informed consumer who can find the best headphones for your needs faster. Also, at our lab, the goal is to never be satisfied with good enough. We're going to spare no expense. I mean, really, if I'm not putting my money where my mouth is at this point, come on, guys, but there is always going to be room for improvement. We know that our tests weren't perfect here for many reasons and no one is more critical about our testing protocols than the very people that we've hired to create them, but our lab is still under construction and achieving our goal of industry-leading testing is going to take some time. There's also just much more that we'd love to test outside of just the frequency response of headphones, like the microphones, noise-canceling, distortion testing, even trying to find ways to apply response curve data to the human perceptual system. So if there are tests you guys would like to see, let us know in the comments because this is just the beginning. The beginning of this message from our sponsor who's going to help me pay for this. Enlisted as a free-to-play World War II multiplayer shooter available on PC, PS5, PS4, Xbox Series X and S, and Xbox One with cross-play. It is a focus on historical authenticity and gameplay that always keep you in the middle of the action. You'll be placed in large-scale combat alongside dozens of soldiers, vehicles, and aircraft directly in famous historical campaigns, like the invasion of Normandy. There's hundreds of firearms and specialized weapons, from common ones seen throughout the war to rare prototypes you hardly see in other games. There's even building construction and destructible items in the environment, and if you use our link, you'll get a free bonus just for signing up, including three days of premium time and several orders for troops and weapons. So head to the link in the description and start playing Enlisted for free today. Thanks for watching. If you're interested in more headphone content, check out our video where we did some subjective testing of $35 knockoff AirPods. Spoiler, our staff by and large actually preferred them to the real thing.