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Crowd-developing headphones here pt.1

Hi folks!

This is my first post here @hydrogenaudi.io. I've been a long time lurker and learned a lot about audio here. I really love the more scientific approach of guys to the audio here than in other forums as after all audio these days like wine tasting is A LOT about perception. Unfortunately, nobody in the industry conducts blind tests in an appropriate manner to eliminate biases when evaluating products. As a result, it's extremely hard to know where the "best bang for the buck" is  :'(

Sorry for some mumbling at start  :P

Why am I making this?
I am making this post as we are a small team in Helsinki crowd-developing a pair of noise canceling headphones and I want to have folks of hydrogenaud.io to pitch in to help make right compromises. While our team is small we are developing the product with GrandSun a top tier audio ODM that produces and develops for Audeze as well as other top-notch brands. My purpose is not to be a shill but make sure that product is good as well as to send out some prototypes for review along the way. We have one btw already (very raw)



Super short about my background:

Our team has previously crowd-developed a 2-in-1 laptop together with folks passionate about laptops. You can read more about it here for example. Now we are taking on the next project based on our community www.eve.community and folks from r/headphones subreddit feedback.

Why pair of noise canceling cans?

We've run a big survey on r/headphones and our community and realized that there is quite a lot of potential to provide better value in over-ear noise canceling headphones. Also this makes a lot of sense as environments around us are getting louder and in many cases we need to ramp up volume to hearing damage levels to achieve needed bass performance (it's a separate topic but frequencies below 400HZ require a substantially higher sound level to sound equally loud to frequencies above 400HZ)


Floyd.E.Toole

Anyways the key point is that we can achieve better audio quality in louder environments by making sure that environment Low frequencies don't mess with our music. The chart above shows what we can hear and at what sound levels as well as when the extrnal environment intercepts with our listening experience.

Our approach:

Our work is very much inspired by work of Toole in terms of approaching audio from more scientific angle rather than what certain product feels like. I strongly recommend anyone interesting in audio to read the book. It's a gem that BUSTS so many marketing Myths

We also very much believe that everyone in 2019 deserves to experience good audio that doesn't cost an arm and a leg.

What's missing in ANC headphones today?


So something like this is missing in the market. Currently, you have headphones that either provide great comfort and user experience (meaning features) or then you get headphones that sound great for their purpose but lack needed features or comfort. Also, you have a cheap zone which is generally compromised especially in terms of design and feel.

So what we've got so far?

We have so far asked a ton of questions and ended up with this:



I know audio is not really about specs but rather real-life performance. So here is what we are doing now to achieve better product than what's available out there:


1. We will use latest Qualcomm QCC5124 chipset for bluetooth 5.0 low power performance and reliability. Generally, QCC5124 has 3x baterry life of its predecessor with Bluetooth 4.2
2. We will use a dedicated DSP from Sony CXD3782. Same DSP as is used in WH1000MX3. The goal here is to have dedicated chip to handle noice canceling alone versus having everything on QCC5124 (this is where many products fail in our view by saving 2-3 USD in BOM)
3. We will use a dedicated amp from ADI to make sure that headphones are loud enough and can give a fuller sound.
4. We will use GrandSun's ironless driver which when we tried in real life produces super clear audio comparing to normal dynamic. It allows to achieve THD < 0,01% and most importantly it just sounds noticebly clearer in real life without sacrifising any of the timbre and adding any extra coloration to the track


I will do my best to explain the difference below:

Grandsun, our manufacturer, has been developing it for past 7 years and I have to say that all their research paid off! As mentioned, the beautiful thing about this driver is that it allows to reproduce music more clearly and with  **noticeably less distortion**  (THD) especially at louder music levels then with normal dynamic driver. So how does it differ from normal driver?

Normal Dynamic Driver



Driver we will use (the manufacturer calls it ironless but we need to come up with a better name :))



The main difference between two drivers is how the magnetic current moves. In a normal dynamic driver magnet and voice coil have their own magnetic fields that FIGHT with each other causing extra vibration in diaphragm resulting in higher harmonic distortion. Iron-free driver from GrandSun on the other has 20 strong magnets that align magnetic forces with the voice coil magnetic filed and produce a much cleaner sound. Essentially there is no contact of the normal metal frame part and the diaphragm due to the strong magnetic field.

If you want to read more on it here is a patent :D

Here is the real life pic of the driver itself:




Some of the other key features requested so far:



All of the discussion is coming from our community so far.

So now what's next?

I won't aks many questions in this post as it's pretty long already. The key question I have is:

Is it something you folks find interesting? How are the specs looking so far? What is missing?

If you want me to continue telling about the journey here then get ready to receive more questions and super happy to answer any production, etc related questions.

Cheers!


Re: Crowd-developing headphones here pt.1

Reply #1
You mentioned the work of Floyd Toole, but are you also aware of the work being done by Sean Olive in this very area?
https://seanolive.blogspot.com/

In particular, the target frequency response curve his team @ Harman has developed! With the aid of MiniDSP's headphone amp and headphone measuring device, I've calibrated my IEMs and headphones to their respective Harman target responses, and I'm really pleased with the results.

When measuring IEMs and headphones, it quickly became apparent to me that it's essential that the devices form a good air-tight seal with one's head, but this can be achieved with headphones which don't clamp too tightly to one's head (ouch). In the case of the Fostex T50RP IIs, the stock ear pads are too shallow to be effective, but when replaced by deeper pads from a Shure headphone, they can form a proper seal, and frequency response measurements look vastly better, in fact, the T50RP + Shure combo can be almost perfectly calibrated to Harman's target response.

Any thoughts about implementing cross feed?

Re: Crowd-developing headphones here pt.1

Reply #2
You mentioned the work of Floyd Toole, but are you also aware of the work being done by Sean Olive in this very area?
https://seanolive.blogspot.com/

In particular, the target frequency response curve his team @ Harman has developed! With the aid of MiniDSP's headphone amp and headphone measuring device, I've calibrated my IEMs and headphones to their respective Harman target responses, and I'm really pleased with the results.

When measuring IEMs and headphones, it quickly became apparent to me that it's essential that the devices form a good air-tight seal with one's head, but this can be achieved with headphones which don't clamp too tightly to one's head (ouch). In the case of the Fostex T50RP IIs, the stock ear pads are too shallow to be effective, but when replaced by deeper pads from a Shure headphone, they can form a proper seal, and frequency response measurements look vastly better, in fact, the T50RP + Shure combo can be almost perfectly calibrated to Harman's target response.

Any thoughts about implementing crossfeed?

Just started reading work of Sean :) You read my mind there :)

As for the cross feed, it's an extremely likely add on. We are having our first build with it as its a very easy way to add spaciousness to sound and let ears feel more "free". Cross feed is especially impactful in older recordings. Helps you have Beatles not all in the centre of your head :)

And by deeper earpads you mean their z-height? How deep are your shures:)? Can you measure as currently, we are testing 18 and 25mm depth. The only issue is that noise cancellation suffers with deeper, softer pads. 

Re: Crowd-developing headphones here pt.1

Reply #3
What would be target price for these?

Re: Crowd-developing headphones here pt.1

Reply #4
What would be target price for these?

Even the most premium over ear ANC headphones don’t cost more than 120USD to make. So we will make sure to have a very fair pricing without any crazy packaging focusing on delivering only on aspects people want. We will share the pricing after locking the Industrial design and all the certifications(they end up costing a lot) especially if we choose to use HiRes or THX vanity stickers

So stay tuned and we will soon share it !

Re: Crowd-developing headphones here pt.1

Reply #5
1. We will use latest Qualcomm QCC5124 chipset for bluetooth 5.0 low power performance and reliability. Generally, QCC5124 has 3x baterry life of its predecessor with Bluetooth 4.2
How does this power saving translate to headphones, which don't use BT Low Energy, but BT Classic (3.0)? I see some headphone manufacturers that market BT 5 and many users that believe that BT 5 brings upgraded audio and/or performance but that's not the case, it's just improvements in BT LE. Unless there is a BT LE component in the headphones (heart rate sensor, etc.), how could it save power if the bulk or all of the power is being used by the A2DP and HFP profiles which don't use BT LE?

EDIT: I'll answer my own question, it seems the power savings aren't from BT 5, but from the SoC itself https://www.qualcomm.com/products/qcc5124

I have another question, would it have Google Assistant integration like the Sony and Bose ones? Thanks.

Re: Crowd-developing headphones here pt.1

Reply #6



How does this power saving translate to headphones, which don't use BT Low Energy, but BT Classic (3.0)? I see some headphone manufacturers that market BT 5 and many users that believe that BT 5 brings upgraded audio and/or performance but that's not the case, it's just improvements in BT LE. Unless there is a BT LE component in the headphones (heart rate sensor, etc.), how could it save power if the bulk or all of the power is being used by the A2DP and HFP profiles which don't use BT LE?

EDIT: I'll answer my own question, it seems the power savings aren't from BT 5, but from the SoC itself https://www.qualcomm.com/products/qcc5124

I have another question, would it have Google Assistant integration like the Sony and Bose ones? Thanks.

We had a discussion here about Alexa vs. Google Bisto. We decided to go with Google Bisto (meaning you don't need your smartphone to use google assistant and it's not tied to your Phones OS version)

As for the battery saving. Basically, an average 750mah headphone ANC headphone battery normally lasts 20 h on paper while QCC5125 should last 60-72h. We still need to do real-life testing. For us nevertheless, since we use dedicated DSP and Amp we will have more of normal battery life as they both consume similar power to QCC5124 :)

Re: Crowd-developing headphones here pt.1

Reply #7
With Google Assistant headphones you still need the smartphone though (or tablet).

Re: Crowd-developing headphones here pt.1

Reply #8
 
With Google Assistant headphones you still need the smartphone though (or tablet).


You are right. I wrote smth awkward. There is a way not to need a smartphone with google assistant by adding WiFi module on headphones but that doesn’t make any sense considering battery drain. I’ve tried few prototypes like that. As for our headphones there by having Bisto we will not be tied to the smartphones version of OS or google assistant limitations. So our headphones would have same functions as Google he products do. For that we will have to take around 1 month to get google certification for the voice assistant.





Re: Crowd-developing headphones here pt.1

Reply #9
If you choose to implement crossfeed, it should be possible to fine tune it and to turn it off.
Also please consider wind resistant ANC mics. All ANC headphones I tested suffer from wind noise amplification when ANC is on.
Keep calm and opusenc --bitrate 128

Re: Crowd-developing headphones here pt.1

Reply #10
Well I find this interesting. My personal priorities with such a headphone would be:
- Comfort.

- I appreciate more noise cancelling than "sound quality". I put that in quotes because of course I would like them to not sound like crap, but there's a certain point where I just don't care, I'm easy to please, I'm happy with most of my BT headsets including Sony SBH70 and JBL Reflect Aware and Reflect Fit.

- Good sound isolation in addition to active noise cancelling. That's a good combo of high freq and low freq blocking which the two techniques are best at, respectively. The best noise blocking I get right now is with my Shure noise isolating earbuds and my Bose QC 25 on top of them in NC-only mode.

- A dedicated button for Assistant. It's pretty annoying that Sony decided to sacrifice the NC/Ambient/Off button in order to make it the Assistant button, so I have Assistant disabled in my Sony headsets.

I sleep in the daytime, plus I have to work in a noisy office (loud equipment fans in the same space) so this is important.



Re: Crowd-developing headphones here pt.1

Reply #13
If you choose to implement crossfeed, it should be possible to fine tune it and to turn it off.
Also please consider wind resistant ANC mics. All ANC headphones I tested suffer from wind noise amplification when ANC is on.

Very valid point sir! Since ANC is used a lot outside. As for the crossfeed i agree we also think it's not a sin to include EQ options in the app for people who know what they are doing :) Increasing bass a bit when not playing music loudly makes total sense for example!

Re: Crowd-developing headphones here pt.1

Reply #14
Well I find this interesting. My personal priorities with such a headphone would be:
- Comfort.

- I appreciate more noise cancelling than "sound quality". I put that in quotes because of course I would like them to not sound like crap, but there's a certain point where I just don't care, I'm easy to please, I'm happy with most of my BT headsets including Sony SBH70 and JBL Reflect Aware and Reflect Fit.

- Good sound isolation in addition to active noise cancelling. That's a good combo of high freq and low freq blocking which the two techniques are best at, respectively. The best noise blocking I get right now is with my Shure noise isolating earbuds and my Bose QC 25 on top of them in NC-only mode.

- A dedicated button for Assistant. It's pretty annoying that Sony decided to sacrifice the NC/Ambient/Off button in order to make it the Assistant button, so I have Assistant disabled in my Sony headsets.

I sleep in the daytime, plus I have to work in a noisy office (loud equipment fans in the same space) so this is important.

Interesting points you have here! Especially the comfort part. As often times you can achieve better noise cancelation by making tighter earpads and headband. But I agree nothing is more annoying than ANC headphones that start hurting you after a few hours of use. I really want to hear your thoughts when we send prototypes out :)

Yeah, as for buttons I am button guy... and our manufacturer is really obsessed with touch every time we have to convince them to have those.

What is the most common use case for you with your headphones and google assistant?
And you Shure/Bose combo is quite awesome I have to say! Have't tried doing that before :)

Re: Crowd-developing headphones here pt.1

Reply #15
Oh I forgot one thing but it might not be feasible or desirable for most people, I like replaceable batteries, preferably regular AAA ones. My QC25 uses one AAA battery for noise cancellation and it lasts a very long time, plus there's a space for a spare in the case. I don't know how much power Bluetooth can add to that but it can't be that much that non-replaceable Li ion rechargeables are necessary. Maybe weight could be an issue, don't know.

Re: Crowd-developing headphones here pt.1

Reply #16
+1 for replaceable batteries, I can live without these but it's preferable for environment saving reasons, and also for possibility of easy "repair".
And yeah buttons are better than touch interfaces for headphones. There are only so much things that are necessary to control from headphones themselves, no need to complicate that, and everything else can be "set and forget" from a companion application.
Keep calm and opusenc --bitrate 128

Re: Crowd-developing headphones here pt.1

Reply #17
Oh I forgot one thing but it might not be feasible or desirable for most people, I like replaceable batteries, preferably regular AAA ones. My QC25 uses one AAA battery for noise cancellation and it lasts a very long time, plus there's a space for a spare in the case. I don't know how much power Bluetooth can add to that but it can't be that much that non-replaceable Li ion rechargeables are necessary. Maybe weight could be an issue, don't know.

I know batteries are cool and we wanted to have them but unfortunately replaceable slot just takes too much space. And in ANC headphones space is everything. While BOSE and SONY talk about their DSP implementation allowing for great ANC performance it’s mainly due to their passive noice canceling that such a good result is achieved.  And passive noise canceling needs space inside. But this is definitely an idea for second gen!

Re: Crowd-developing headphones here pt.1

Reply #18
1. We will use latest Qualcomm QCC5124 chipset for bluetooth 5.0 low power performance and reliability. Generally, QCC5124 has
This article about BT audio performance could also be helpful - https://habr.com/en/post/456182/. Please, pay attention to the section "Bluetooth 5, Classic and Low Energy".

My audio quality research for some BT codecs - http://soundexpert.org/articles/-/blogs/audio-quality-of-sbc-xq-bluetooth-audio-codec
keeping audio clear together - soundexpert.org

Re: Crowd-developing headphones here pt.1

Reply #19

This article about BT audio performance could also be helpful - https://habr.com/en/post/456182/. Please, pay attention to the section "Bluetooth 5, Classic and Low Energy".

My audio quality research for some BT codecs - http://soundexpert.org/articles/-/blogs/audio-quality-of-sbc-xq-bluetooth-audio-codec
Cheers will have a look!

Re: Crowd-developing headphones here pt.1

Reply #20
Not sure if BT spec permits that but for music listening it'd be neat to have option to sacrifice latency for reliability (increased buffering or something). latency doesn't really matter for listening to music, but when sound skips, it's ugly.
Keep calm and opusenc --bitrate 128

 

Re: Crowd-developing headphones here pt.1

Reply #21
You might find this interesting or helpful.  I have the Parrot Zik3, which has ANC, EQ, and a unique touch-surface for control.  Generally ok sound, but they have many failings. 

Their APP...This controls everything, all the tweaks and adjustments, EQ, and cross-feed.  But it won't do a thing without the host device being connected to the internet.  You have rather vague and clumsy control of EQ.  You can save "tunings", even share them, and associate them with an individual track, but none of that can happen without your host device connecting to the Internet and logging into your account.  Saving tunings is good, not saving them in the device is awful.  It means on an aircraft you don't have access to your tunings!  I don't believe EQ settings are "social", no need to share them.  You can't make changes to your settings without logging into your account and that's terrible. Their basic sound without EQ is bright and edgy, so EQ is mandatory. The ANC is good, but  can be overloaded by high SPL low frequency noises.  They have a passive, wired option that lets you use the headphones without powering them.  SQ in that mode is only fair, however.  Touch control is sometimes impressive, sometimes erratic.  The auto-shutoff feature where the electronics are put to sleep if you take the headphones off fails early in life, just outside the warranty period, not fixable.  Battery is user-replaceable but an odd type.  Batter holder is not secure, battery can come loose.  Removable left ear cover is held on with magnets, but they are too weak. The headphones seal well, but they also seal in heat.  Wearing outside in warm weather is challenging. Recharging is via micro USB, recharge time is unusually slow.  Their cross-feed options range from horrible to quite usable, with room simulation being the more useless function.  Concert Hall in my headphones?  No thanks.  While EQ can be associated with tracks, cross-feed settings cannot.  That's the inverse of what is really needed, you'd want cross-feed settings to sync to specific tracks...if you use it at all.

 
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