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hurtyewh OP t1_iy7xfr7 wrote

I can't find any information about the company. They've gathered apparently over 2,5M$ with a goal of $20 000 (on Kickstarter) and had some extremely sketchy clips with musicians and producers. It seems that Grell is a hired consultant "on the project" as he puts it, but it seems the overall design was finished long before him. The image shows graphs from Grell's video and they look rather horrific, but what else could it be besides basic measurements? Grell Audio TWS 1 were nothing special so is this just an industry legend trying to cash out with his name? How big a part did Grell have in the creation of the legendary Sennheisers or could it be he's got much less to offer outside the company (I'm not very familiar with his career)? Are there any good reasons to have two (small) bass-mid drivers and two mid-high drivers if it's a two-way system?

I'd love to be optimistic about these since closed back metal headphones are exactly what I'm looking for at the moment, but I suspect they're going to be garbage.

Here's Grell's video about them: https://youtu.be/VK17xvT-nwE

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rhalf t1_iy8dgyg wrote

There are very good reasons to use two or more transducers.Dynamic transducers are cheap and lightweight. Unfortunately when you use one driver, then it needs displacement to play bass and phase accuracy to play highs. The former requires big size, the latter small size, or you'll get destructive modes all over FR.

So far we arrived at a consensus that 40mm driver is the golden compromise, however the bass will roll off and it doesn't look good in the marketing material. That's why 50mm driver are being marketed towards the "casual consumers". They have more displacement, but are bad at everything else and really only work with waveguides.

So you want to split the signal. The problem is that you need to find the actual drivers. Not only that, once you find the drivers of the right size, they need to make some quality noise. This is difficult, but it doesn't end there. The high quality drivers need to be mass manufactured or else the headphone will cost a fortune. So you end up using whatever basket of sketchy parts you can collect. In this case it seems like they found some Chinese earbud speakers, which probably were too small to cross them to the big boys, so they had to use two of them. Two drivers have more output and if they're small enough, they play like one driver. I probably sound very critical here, but this is actually how you design good audio.

The big boys still play quite high IMO, but what do I know. Optimally you want the bass to be completely separated from the rest but, as above, it's not always viable.

With drivers as small as theirs, they probably realised that they can reorient them so they're playing with the idea of HRTFing the driver's response. The important part is that they are as close to your ear canal as possible.

When you use multiple drivers of the same kind, the costs go down. Sometimes that's the difference maker. There's this company that makes loudspeakers out of tweeters. They can undercut other manufacturers and that's why they're popular.

In the past a headphone like this was not a viable option. Today we're getting to the point, when energy efficient and highly integrated chips can handle devices like these. The goal right is to find that secret sauce.

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