Hey there folks!
Some time has passed since our last update on muse. Today we are bringing all the latest news about our headphones project!
In the past few weeks we were working with the manufacturer of headphones (their name is GrandSun BTW) to kick off the project formally. The reason we picked this manufacturer is because of the driver technology they invented, their capability (Audeze, Master & Dynamics, etc) and willingness to work.
Headphone radio testing facility
Let’s get started!
Muse status update and how will we make a kick-ass pair of cans
First Muse very rough Prototype using 3d printed parts
As I’ve mentioned few times already we’ve partnered with a manufacturer that is not all about cutting angles but rather being ambitions. They also happen to have a unique driver design that beats the normal dynamic driver. We were able to build up a prototype quite quickly with 3d printing testing out basic components and function
How to get kick-ass quality form a pair of over ear noise cancelling cans?
After talking to an awesome guy who is a CTO of a factory behind Audeze we have a much clearer picture
Bluetooth headphones are not a simple product. Unlike open back Sennheisers like HD650 designed to work with an external DAC, AMP and DSP, Bluetooth headphones need to have all those components inside to work wirelessly as they need to process digital signal sent over Bluetooth to analog . In Bluetooth headphones it is important to treat all the key features equally as otherwise there is a big risk of making a compromised product. For instance, if we would make the best sounding over ear headset that would have poor Bluetooth connectivity and low level ANC it would end up being a bad product. Let me tell you more about that key parts of the headphone are and why they matter
1. Headphone drivers
Are responsible for creating actual sound by moving air. Different materials for diaphragm and magnets can affect the cleanliness of sound but the type of driver has bigger impact on sound quality. There are various types of drivers, dynamic, planar, electrostatic, hybrid they all have their pros and cons. We will be using a new driver type developed by our manufacturer that allows to dramatically reduce harmonic distortion caused by the conflicting magnetic fields of a normal dynamic driver. (Read more below)
2. Headphone Chipset
Is similar to a processor in a laptop. It is attached to the motherboard (SMT process) and can have DSP, DAC, AMP and Bluetooth module included. Also depending on the chipset you have possibility to support different codecs. For example Qualcomm chipsets support APTx and it’s variations like HD while some support only AAC and LDAC. Same as with laptops you can choose to have intel integrated graphics or you can go for dedicated graphics card. Having a dedicated graphics card allows you to achieve substantially better graphical performance as it’s the only job of GPU. Same with headphone chipset. You can get an ok performance by using integrated DAC, AMP, DSP but having them dedicated allows for a substantially better performance. Main trade offs are size, extra cost and power consumption (thankfully there is no heat decipation issues in headphones :D).
This picture shows the idea of how amp works amplifying small current coming directly from the mic to output larger one to produce sound
A headphone amp is a relatively low-powered amplifier that raises the low-voltage audio signal from a source device (be it a turntable, PC, or smartphone) to a sufficient level such that it can be converted into sound waves by the speakers inside your headphones. It works like the amps used to power full-sized speakers but operates at a lower scale. Good amp ensures that amplified current is clean and stable.
DAC - Digital to Analog Converter converts digital 0s and 1s in which the song is stored to analog signal. Afterwards it sends that analog signal to an amplifier. When you hear digital recordings, you’re actually listening to an Analog signal that was converted from digital by a DAC.
DSP stands for digital signal processing. In general DSP is capable of
- Generating wider frequency output
- Filtering out any reverberation
- Gain control
- Real-time channel mixing
Most importantly in our case DSP affect the Noise Cancelling performance. Currently the best noise cancellation DSPs are used by BOSE and SONY. Fortunately Sony’s latest gen DSP is available in the market and will alows us to have top notch noise cancelling
Ok so let’s first recap the specs so far:
After studying various chipset options we concluded that Qualcomm QCC5124 is a no brainer as it has the best Bluetooth performance in terms of stability in the market, has Bluetooth 5.0 allowing for at least 2x battery life and supports APTxHD, ACC and LDAC(if we decide to use it).
As for the noise cancellation and audio quality we had 2 options:
- To go with an all in one solution, so to use QCC5124 chipset from Qualcomm that has integrated DAC, AMP and DSP
- USE QCC514 for Bluetooth 5.0, APTX HD and other codecs while using dedicated AMP, DAC and DSP.
While QCC5124 is considered to be a flagship chip nowadays after testing it we think it’s not yet there when it comes to noise canceling and audio quality so we decided to go with the second option as having separate modules to handle different tasks will substantially improve individual performance of headphones.
Is there any downside of using the second option? Increased cost in few dollars per unit is the only real disadvantage but we think that the result is well worth it!
We are planning to use DSP from Sony WH1000MX3 model for the noise cancellation and we will be testing various options for DAC and AMP
Now a bit more about the driver we use. 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. Driver we selected allows you to enjoy your favorite songs at a new depth level and hear much more finer details. So how does it differ from normal driver?
Normal Dynamic Driver
Driver we will use (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.
Now some Questions to you
How important is smart Assistant to you assuming it does not add cost?:
- I would love to have Google Assistant
- I would love to have Alexa
- I don’t care to be honest
Based on my explanation did you get the idea of how GrandSun’s driver work?
Coming next: Production & Testing of headphones!
Headphone smart assistant test room