The Lab Just Bought This…

[AdamFromLTT]

We are making our first big purchase of testing equipment for the new lab, but there are a lot of things to consider. For headphone testing, we are purchasing a Head and Torso Simulator, but choosing between two state-of-the-art products requires some very thorough testing.
 

Buy Sennheiser HD 650 Headphones: https://geni.us/CDZm3

Buy Audio-Technica ATH-M50X Headphones: https://geni.us/nvBNo

Buy KZ ZS10 Pro in Ear Monitor Earbuds : https://geni.us/y9zuW2d

Purchases made through some store links may provide some compensation to Linus Media Group.

 

[MultiGamerClub]

what the blob is that

edit: ohhhhhhhhhhhhhhhhhh

Edited May 30, 2022 by MultiGamerClub

[quater]

Nice. Can’t wait for some real data! and snake oil debunking...
 

[darknessblade]

So we will soon see a FULL scale, headphone testing video. finding the best Heaphones for any budget

[10leej]

So since the writeups are going up on floatplane I take it that their going to be behind a paywall? Because thats like the one thing I'd be willing to spend money on floatplane because I kind've dislike the service overall.

[AnonymousGuy]

It's like Linus doesn't know Rtings exists.  Cable testing was something new...headphone testing at best you're a shittier copy of Rtings.

[Spuriae]

I'm guessing the GRAS 45BB was the third model? Does this mean that the graphs are intended to be normalized to a non-Harman target?

 

Also, I noticed that the human testing shown here had a cutoff at 2kHz, which means the results would have been dominated by cheek coupling rather than pinna or ear canal coupling. Is there additional data for human subjects' pinnae responses, or is it assumed that ITU P57 is enough of an entrenched standard for it to not matter? Given that one of the reasons for settling on the 5128 was the pinnae, I'd be interested in seeing if its pinnae are indeed more accurate for the general population, given that even minor changes to pinnae can have significant effects on the treble response; see https://imgur.com/a/Jf5bLms.

 

For instance, here is a graph I put together of some different measurements of the same headphones, using Auto EQ's corrections for average error for each data source (i.e., post-compensation to a "corrected average" for each test rig). Individual headphone variance is low at low frequencies (until below ~100Hz, where seal really begins to dominate), but above 2kHz (where the cutoff in the video's testing was), variance increases significantly due to pinna coupling. Canal resonances >6kHz are also significant but not shown here.

6 minutes ago, AnonymousGuy said:

It's like Linus doesn't know Rtings exists.  Cable testing was something new...headphone testing at best you're a shittier copy of Rtings.

Rtings uses a HMS II.3. Rtings measures different characteristics, of different headphones. There's nothing wrong with more measurement sources; oratory, crinacle, ASR, headphones.com, etc. all have their own sets of high-quality measurements that serve a different purpose than Rtings. There are plenty of useful measurements that Rtings doesn't do as well.

 

[kaiosz]

Super excited to see tests with these. A ton of my headphones don't even have proper measurements online.

[porina]

 

If you get the torso then you can also use them to model clothing, kinda  Here's a 4128 with the original wan hoodie some years back.

 

Curious what the setup is, since this was my old job. Place doesn't exist any more  

[Psittac]

I would LOVE to see headphone testing done with different earpads if at all possible.  Granted this adds exponential amounts of testing but pads are one of the easiest ways to change sound signature.  I took my T50RP which I loved and put a recommended pair of sure pads on them and almost threw up in my mouth a little.  Then I put on another pair of zmf protein pads and they're on them right now and HELLO bass city.  Granted I did put the sure pads back on and grew to enjoy them but only for certain music.

 

I've never been a graph=sound kind of person in the slightest, I think that it is FAR too subjective, but I've been keen on the idea of using charts as a tool to my own selections rather than an end all be all like some would say they are.  This will be a great experience for me to dive into the technical side of this hobby.

 

Also tubes would be awesome but that's not at all feasible, there are endless tube amps and configurations not to mention tube's are about as subjective as you can get.

[quater]

18 minutes ago, porina said:

 

If you get the torso then you can also use them to model clothing, kinda

 

 

So how is the hoodie changing frequency response?

 

[AnonymousGuy]

1 hour ago, Nimrodor said:

There's nothing wrong with more measurement sources

 

Hard disagree on that.  All LTT is going to do is add noise to the space.  They can't even build a  server that doesn't have amateur-level issues with storage reliability, I'd trust them with audio measuring as much as I'd trust a mechanic to do brain surgery.  

 

Quote

 There are plenty of useful measurements that Rtings doesn't do as well.

Such as?  They already have so many measurements that it's overwhelming to even look at directly.

[misterpumpy]

10 minutes ago, AnonymousGuy said:

Hard disagree on that.  All LTT is going to do is add noise to the space.  They can't even build a  server that doesn't have amateur-level issues with storage reliability, I'd trust them with audio measuring as much as I'd trust a mechanic to do brain surgery.  

 

Such as?  They already have so many measurements that it's overwhelming to even look at directly.

Having many measurements will not necessarily result in the best measurements for what they are trying to capture. I have no comment on how good or bad LTT measurements are, because they haven’t unveiled their headphone testing engineer, they haven’t listed their in depth view on testing, what they bring to the table, etc. as for adding noise, asr + crinacle + even rtings are not exactly fully overlapping with their readership—the idea that suddenly everyone would be drowned out with confusion bc LTT jumps in is goofy. Folks at ASR will ignore LTT and keep listening to Amir, I don’t see any crinacle readers or viewers switching to LTT…I can see some folks moving from RTings, but to be honest I think LTT is trying to educate an audience that is too surface level to bother with ASR or crinacle or the folks at headphones dot com. 

[quater]

36 minutes ago, Psittac said:

Also tubes would be awesome but that's not at all feasible, there are endless tube amps and configurations not to mention tube's are about as subjective as you can get.

If you know and define what you want from an amp (amplify) it is easy to test.

You can just quantity every derivation form the mathematical ideal. (linear transfer function)

 

All a tube(amp) can do is applying some non linear transfer function to the signal (like a LUT for audio). 

For the believers that thinks there is a magic tube transfer function / distortion that makes everything better. Why don’t they apply it in the studio?

 

If you want effects to change your sound. fine. your having a computer you can do what ever you dram of and more in DSP. for free. 

 

46 minutes ago, Psittac said:

I've never been a graph=sound kind of person in the slightest, I think that it is FAR too subjective,

Whats the difference to a color calibrated Monitor or Printer?

One might like the over saturated look of some monitor subjectively more. but more faithful to reality is not subjective.

[Spuriae]

15 minutes ago, AnonymousGuy said:

Hard disagree on that.  All LTT is going to do is add noise to the space. 

ASR's early measurements had amateur-level issues, and didn't do much more than add noise to the space. Now they're a pretty good resource in their own right. Even if it starts rough (which is by no means a given), wait and see. Even lower quality headphone measurements which don't conform to standards often have something valuable to add to the conversation, for instance, diyaudioheaven and reference-audio-analyzer can be great sources of information, even when higher quality measurements of the same devices exist elsewhere.

 

For instance, high quality measurements of the Sennheiser PXC 550-II exist on both the GRAS (oratory) and HEAD (Rtings) systems. But much of the population wears glasses, and for them DIYAH's flat plate coupler measurements are significantly more relevant.

20 minutes ago, AnonymousGuy said:

They can't even build a  server that doesn't have amateur-level issues with storage reliability, I'd trust them with audio measuring as much as I'd trust a mechanic to do brain surgery. 

Linus isn't going to be the one personally performing the measurements, and this video shows that the person conducting the experiments isn't an amateur.

21 minutes ago, AnonymousGuy said:

Such as?  They already have so many measurements that it's overwhelming to even look at directly.

Sensitivity

Impedance

Seal/Pinna variability

Alternate configurations

Powered Self-noise

Step/Impulse

Decay

Harmonic Order

Linearity/Compression

[Ultraforce]

1 hour ago, AnonymousGuy said:

They can't even build a  server that doesn't have amateur-level issues with storage reliability

Actually Kamloops server, which is their offsite back up hasn't had any storage reliability issues. Only reason there was a video where we saw it was that it was filthy, might have had metal in it from renovations at the data centre it's stored at and I think maybe to expand it further.

Though also as others mentioned a big part of LTT Labs is getting professionals which is to say people who aren't simply good writers who are hobbyists and former employees of computer stores.

[Psittac]

1 hour ago, quater said:

If you know and define what you want from an amp (amplify) it is easy to test.

You can just quantity every derivation form the mathematical ideal. (linear transfer function)

 

All a tube(amp) can do is applying some non linear transfer function to the signal (like a LUT for audio). 

For the believers that thinks there is a magic tube transfer function / distortion that makes everything better. Why don’t they apply it in the studio?

 

If you want effects to change your sound. fine. your having a computer you can do what ever you dram of and more in DSP. for free. 

 

Whats the difference to a color calibrated Monitor or Printer?

One might like the over saturated look of some monitor subjectively more. but more faithful to reality is not subjective.

I guess that I don't understand testing very much, I just never cared about it enough to look into it.  The problem I have is the people that hammer the graph's and numbers without taking anything else into account.  They always have a superior attitude as well.  To me a calibrated monitor or printer is still conveyed in a visual manor. And like I said, I'm keen on looking into the technical side, but I don't think the comparison is a direct one.  But again, this could be due more to a lack of education.  Are monitors calibrated across the brightness level? Across the hz? Across the whole monitor? With a variable load?  I honestly don't care much about color accuracy either though. *To summarize I've always been a skeptic of using a static image to portray music which is variable and based over time.  Monitor's are digital with million's of output devices, headphones are analogue with two output devices.

 

My vague assumption of why tube amps would be difficult to graph and show the nature of the tube is that it's not a 1 to 1 effect across the board, it's a live load and changes according to each input.  At least on tube only amps.  I think of it more like an effect on a video vs an effect on a picture.  But again I don't understand how tube's work or how testing works.  But at the same time, that wasn't my main point, more that the options are to numerous and the audience is to limited.

 

I just don't like the mindset of charts and graphs when it comes to audio but I have probably gone to far by not using them at all.

 

 

[Needfuldoer]

6 hours ago, 10leej said:

So since the writeups are going up on floatplane I take it that their going to be behind a paywall? Because thats like the one thing I'd be willing to spend money on floatplane because I kind've dislike the service overall.

I suspect (hope) they just put their writeup for this specific test on Floatplane, and this won't be the standard operating procedure for the Labs once it's up and running. There just isn't a dedicated Labs site that's open to the public yet.

 

(But then why not post them to the forums for now?)

[Lightwreather]

1 hour ago, Needfuldoer said:

(But then why not post them to the forums for now?)

I forget which wan show this was one, but iirc they were going to use the linustechtips.com domain for the Labs content

[my2dumbledores]

I think it was a mistake not using a GRAS45.
All of Dr Sean Olive's work on the Harman curve was completed with GRAS systems. It's a major factor in why Crinacle, Armin (ASR), Resolve and Oratory1990 all use them.

By using a B&K, you cannot directly compare to the Harman curve. There is a reason Soundguys isn't as respected as these other sources.

Either way, it's still very exciting. Very much looking forward to these new reviews.

[Supreme Calamitas]

I didn't know Stephen Hawking worked for Linus as a headphone engineer...

[LAwLz]

I usually don't watch LTT videos, but I am glad I decided to watch this one.

 

You investing in proper measuring equipment has calmed my scepticism about LTTLabs a fair bit. Back when you announced LTTLabs you said that "of course we will DIY it" and I was fully expecting you to try and build your own dummy head with some crappy microphones or whatever, because "why spend 50K when I can build my own for 100 dollars?".

Good to see that you are buying proper measuring equipment.

 

I hope you got someone who knows how to use these instruments as well. Expensive hardware is wasted if not utilized properly.

 

 

I hope the test results you will publish in whitepapers are a bit more proofread and carefully prepared though.

Mixing up the test results between the HD 650 and M50x is a fairly big "oopsie". 

[quater]

9 hours ago, Psittac said:

 *To summarize I've always been a skeptic of using a static image to portray music which is variable and based over time.  Monitor's are digital with million's of output devices, headphones are analogue with two output devices.

But sound is never a static image? only the change over time makes it a sound.

For the monitor/printer analogy you to work you can change temporal and spatial resolution.

https://en.wikipedia.org/wiki/Linear_time-invariant_system

Quote

Linear time-invariant system theory is also used in image processing, where the systems have spatial dimensions instead of, or in addition to, a temporal dimension.

Or you can assume them headphones as 1 pixel (2pixel for stereo) monitor.

Oh and your Monitor is an Analog device to. its input is digital (if it is not VGA) but the Output is analog.

 

 

A headphone has no long term memory it "know" only what it is currently outputting and what its input signal is what it shuld output.

In layman's therms you go from every output level to every possible output level. do some math and calculate how fast and accurate the headphone produces this output level.

frequency is just a periodic change in output amplitude over time.

 

10 hours ago, Psittac said:

My vague assumption of why tube amps would be difficult to graph and show the nature of the tube is that it's not a 1 to 1 effect across the board, it's a live load and changes according to each input.  At least on tube only amps.  I think of it more like an effect on a video vs an effect on a picture.  But again I don't understand how tube's work or how testing works.  But at the same time, that wasn't my main point, more that the options are to numerous and the audience is to limited.

 

The thing how tube are different is they have more "memory"

they get hot (slowly) and so they change slowly over time.

The same tube can sound different after running for 2h on full power compared to running 2h on low power.

 

 

[Needfuldoer]

2 hours ago, LAwLz said:

You investing in proper measuring equipment has calmed my scepticism about LTTLabs a fair bit. Back when you announced LTTLabs you said that "of course we will DIY it" and I was fully expecting you to try and build your own dummy head with some crappy microphones or whatever, because "why spend 50K when I can build my own for 100 dollars?".

Good to see that you are buying proper measuring equipment.

"How close to replicating this $50K dummy head can we get, on the cheap, now that we have one to copy from" could make for an interesting shop video, though!

Edited May 31, 2022 by Needfuldoer

[porina]

3 hours ago, my2dumbledores said:

By using a B&K, you cannot directly compare to the Harman curve. There is a reason Soundguys isn't as respected as these other sources.

My background is telecoms side so I'm not so familiar with the audiophile side or Harman curve, and a quick search is providing plenty of results that don't say an awful lot useful. Is it just a target frequency response curve? Where I used to work we standardised worldwide on B&K, but did look at a stand alone Gras ear simulator at one point as a cheaper alternative. I got one on loan and compared it. We didn't go ahead with it in the end because the response was slightly different to B&K. Not massively so, but enough that it would add complications when comparing and sharing results. While it could be compensated in processing, it was an extra step. Ended up buying another from B&K.

 

1 hour ago, Needfuldoer said:

"How close to replicating this $50K dummy head can we get, now that we have one to copy from" could make for an interesting shop video, though!

If your interest is mainly in the ear and not the head/torso, you could in theory buy the microphone and pinna, and create your own mounting solution for them. A suitable mic was still in the thousands, and pinna in hundreds, but it is far from 10s of thousands. Note I say suitable mic, since you should get one that simulates the ear drum area and not just put any random mic there. This might be ok for internal uses, but if you want to be taken seriously externally then it isn't really an option.