I'm designing a new type of headphone driver.

[SilicateWielder]

Hey guys, I have been designing a new type of headphone driver to combat an issue seen with typical driver configurations meant to spread the sound spectrum acrossed multiple drivers.

 

Regular headphone drivers, or microspeakers as I've seen some call them come in the form of disks that must be placed side-by-side, which is good if you want multiple physical channels on either side, but not good if you're trying to spread out your sound sprectrum, what you end up with is different ranges coming from different directions and with the ear being able to color sound so that you can perceive the direction a sound is coming from this can pose the problem of having inaccurate sound position, which may mean the difference between life and death in some modern gaming title (at least from what I've heard). Yes, I am aware we humans have only two ears, however our brain is an amazing peice of equipment that can figure out where sound comes from based on timing, loudness and how sound has been colored by the shape of our ears. 

 

I originally thought of the idea after a failed experiment I had done with an old pair of headphones I had lying around. I placed a small driver behind the main driver of my headphones and as you can guess it didnt't go too well, nor did I have the time to cut new holes for extra drivers. After thinking long and hard I thought "What if I place a driver within a driver?" And I wasn't talking about physically placing a driver between the membrane and chassis of a driver but actually designing a donut-shaped driver that can fit a smaller driver within the hole in it's center. I began working and I now how two possible designs, the first overlooking the importance of bass ports for tuning, however both designs require a custom magnet. I did search for companies that would produce the magnet I need but there is either little information on how to order one on most of the sites I find. I am currently working on a second revsion of my designs that will use magnets already available on the market.

 

I'd like to know what you guys think, criticism is welcome, I know the basics of how soundwaves work and behave with eachother but not much more beyond that. 

 

Original Design screenshots:

Spoiler

 

First Revision:

Spoiler

 

[Enderman]

Well fisrt of all, headphone drivers do not need to play high SPL

that is why a SINGLE driver plays all the frequencies from 20 to 20khz just fine

I have never heard of headphones that have separate tweeters and woofers and midrange drivers

 

second, "speaker in a speaker" already exists

its extremely common in car audio

 

also kef makes double drivers which have the tweeter in the center of the midrange 

[ZetZet]

There already is plenty of headphone tech and they all sound spectacular. 

 

 

Better put time into designing small speakers for phones, tablets and slim laptops that are powerful on the lower end. 

[ZetZet]

4 minutes ago, Enderman said:

Well fisrt of all, headphone drivers do not need to play high SPL

that is why a SINGLE driver plays all the frequencies from 20 to 20khz just fine

I have never heard of headphones that have separate tweeters and woofers and midrange drivers

 

second, "speaker in a speaker" already exists

its extremely common in car audio

yeah coaxial speakers are basically a staple in car audio. 

 

also used in higher end boomboxes and wireless speakers since you need less space for them. 

[Dackzy]

I think you have a problem with your driver system, since they are already made and there is no need for more drivers in headphones. You should maybe look into making phone speakers better.

[SSL]

1 hour ago, Enderman said:

Well fisrt of all, headphone drivers do not need to play high SPL

that is why a SINGLE driver plays all the frequencies from 20 to 20khz just fine

I have never heard of headphones that have separate tweeters and woofers and midrange drivers

 

Multi-driver IEMs of course, then there's the Enigmacoustics dharma.

 

Headphones generally bypass the HRTF, and so cannot provide directional sound based completely on the specific location of the driver.

[SilicateWielder]

2 hours ago, Enderman said:

Well fisrt of all, headphone drivers do not need to play high SPL

that is why a SINGLE driver plays all the frequencies from 20 to 20khz just fine

I have never heard of headphones that have separate tweeters and woofers and midrange drivers

 

second, "speaker in a speaker" already exists

its extremely common in car audio

 

also kef makes double drivers which have the tweeter in the center of the midrange 

Thank you for the input,

 

From my understanding there are actually multi-driver headphones outside of the surround sound market, but the imaging is usually screwed up because you just cant place normal headphone drivers in a way that won't alter the imaging. I am aware that this technology is available for larger speakers like those used in automobiles but this isn't available on a scale suitable for headphones. IEMs can get away with multiple drivers because the positioning is practically indistinguishable.

 

I get where your coming from but lets consider why we have speakers on stereo systems split into tweeters, woofers, and subwoofers. even if a driver is rated for 20hz to 20kHz, it may not respond to some frequencies within that range as well as it does others, which is why we have Tweeters, woofers, and subwoofers in the first place. By splitting up the frequencies among multiple drivers you can create a more uniform sound signature.

 

I may not be correct with this next part.

Buy anywy, along with what I stated above, some membranes may not handle a sudden and/or  rapid change in direction as well as other membranes. so when it's vibrating and switches from a low to high frequency very rapidly, you end up with delay and that in turn makes the sound muddy. larger drivers are better suited for bass because they need to move large distances instead of accurate distances to form lower frequency sounds, while smaller drivers handle higher frequencies better because there is less mass to move, meaning they can more efficiently move their membrane quickly and accurately, but at the same time the smaller driver may not be able to move the neccessary distance to get accurate defined bass.

 

For example, my headphones handle high frequencies very well, but when it comes to bass it gets a bit muddy and is less defined. A multi driver system would solve the issue of clarity and their ability to respond to different frequencies however we still have the issue of the imaging, which is where my driver concept comes in.

 

[SSL]

8 minutes ago, UnbrokenMotion said:

Not only this but some membranes may not handle a sudden and/or  rapid change in direction as well as other membranes. so when it's vibrating and switches from a low to high frequency very rapidly, you end up with delay and that in turn makes the sound muddy. larger drivers are better suited for bass because they need to move large distances instead of accurate distances to form lower frequency sounds, while smaller drivers handle higher frequencies better because there is less mass to move, meaning they can move their membrane more quickly and accurately, but at the same time the smaller driver may not be able to move the neccessary distance to get accurate defined bass.

 

For example, my headphones handle high frequencies very well, but when it comes to bass it gets a bit muddy and is less defined. A multi driver system would solve the issue of clarity and their ability to respond to different frequencies however we still have the issue of the imaging, which is where my driver concept comes in.

 

 

Headphone drivers are already low mass. The recent craze for "nano thickness" membranes hasn't really been a revolution for sound quality. Drivers don't need to switch between high and low frequency; they can play both at the same time just fine.

 

Multi-driver isn't more common because it adds complexity for little gain. In a speaker system, you need a large woofer to move air, and a small tweeter so that the woofer doesn't break up. In a headphone, bass is massively boosted via the pressure chamber effect. This allows a small driver that is largely immune to break-up to produce low frequencies as well as high. Planar magnetic drivers are capable of particularly extended response because they are both large AND immune to break-up.

 

Driver placement in headphones is less critical to imaging because each driver can only be heard by one ear. This eliminates a number of psychoacoustic spatial cues, including timing difference and the masking effect. And because the driver is so close to the ear, it bypasses the normal interaction of the pinna with the incoming sound; this is why so many headphones have a boosted upper mid-range to compensate.

[spwath]

It doesnt seem very necessary, like what SSL was saying.

 

The drivers are small enough to make good highs, and due to close proximity and a sealed environment produce bass well, and planar magnetics do it even better.

 

Cool idea, I just dont see the use in it.

[SSL]

Don't get me wrong, this idea could produce a great-sounding headphone; I'm just skeptical of some of the justifications provided for going about it this way.

[EndlessOyster]

So your trying to solve the problem of lobeing of certain frequencies by putting two drivers together on a headphone. But thats not a problem because its a headphone and even if there is a large lobe at 60 degrees or what ever there is always the central slobe which is always going into the ear while the rest just go into the side of the ear cup.

[SilicateWielder]

24 minutes ago, SSL said:

 

Headphone drivers are already low mass. The recent craze for "nano thickness" membranes hasn't really been a revolution for sound quality. Drivers don't need to switch between high and low frequency; they can play both at the same time just fine.

 

Multi-driver isn't more common because it adds complexity for little gain. In a speaker system, you need a large woofer to move air, and a small tweeter so that the woofer doesn't break up. In a headphone, bass is massively boosted via the pressure chamber effect. This allows a small driver that is largely immune to break-up to produce low frequencies as well as high. Planar magnetic drivers are capable of particularly extended response because they are both large AND immune to break-up.

 

Driver placement in headphones is less critical to imaging because each driver can only be heard by one ear. This eliminates a number of psychoacoustic spatial cues, including timing difference and the masking effect. And because the driver is so close to the ear, it bypasses the normal interaction of the pinna with the incoming sound; this is why so many headphones have a boosted upper mid-range to compensate.

Ah okay, so imaging isn't so much of an issue. Would how ridgid the material used in a driver's membrane affect the clarity of the sound produced? If not, then what would? 

 

I never said multi-driver headphones are common, I just said that they are out there. 

[Dackzy]

I can see that you have some sort of talent for ideas when it comes to audio. I would love if you could use that on making phone speakers better  

[SilicateWielder]

23 minutes ago, Dackzy said:

I can see that you have some sort of talent for ideas when it comes to audio. I would love if you could use that on making phone speakers better  

I might consider it. But for now I want to get a prototype working based on my current designs. Finding a ring magnet of the right size is very difficult.

[Dackzy]

2 minutes ago, UnbrokenMotion said:

I might consider it. But for now I want to get a prototype working based on my current designs. Finding a ring magnet of the right size is very difficult.

Yeah good luck finding that ring magnet.

[SilicateWielder]

Just now, Dackzy said:

Yeah good luck finding that ring magnet.

I've found a neodymium magnet perfect for a 40mm driver but the problem is seperating the membrane into two chambers. The magnet is 1" od x 1/2" id x 1/8 thick.

 

I might try using an electromagnet or two, I think I have a bunch of copper wire in my scrap bin anyway. Of course, I would have to build a low-power amp/ power supply for that to work. 

[Dackzy]

1 minute ago, UnbrokenMotion said:

I've found a neodymium magnet perfect for a 40mm driver but the problem is seperating the membrane into two chambers. The magnet is 1" od x 1/2" id x 1/8 thick.

 

I might try using an electromagnet or two, I think I have a bunch of copper wire in my scrap bin anyway. Of course, I would have to build a low-power amp/ power supply for that to work. 

Sound interesting

[SilicateWielder]

Just now, Dackzy said:

Sound interesting

By any chance, do you know what a good material would be to use for a membrane? Otherwise I'm gonna try Plastic wrap and hope for the best.

[Dackzy]

3 minutes ago, UnbrokenMotion said:

By any chance, do you know what a good material would be to use for a membrane? Otherwise I'm gonna try Plastic wrap and hope for the best.

No sorry