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Home-Made IEMs - Page 9

post #121 of 2208
Thread Starter 
Quote:
Originally Posted by pdupiano View Post
Come to think of it, I think the biggest part of making custom iems with cross overs may actually be the cross over moreso than which drivers you use. If you can find the right frequency cutoffs for each driver, and the right amount of cross over from one driver to the other, you may end up with the perfect mix. I can see that as being a major contributor to overall sound signature (not quality) and could potentially be the number one cost and differences say between the W3, UM3x, SE530, TFT Pro, etc... and of course the same should apply to even higher end iems.
I don't know how much of it has to do with electronic crossover, but I think you're right about one thing: It's what they're doing with the drivers that is making the most difference. The CI is a popular driver for bass. The TWFK is becoming a popular dual. Before its prominence, the WBFK (which is one half of the TWFK) was the closest thing to a dedicated tweeter. Whether it's the caps, the filters or a combination of the two, it's probably what they're doing with the drivers - much more than the drivers - that is making the difference from one set of monitors to the next.

Whatever the case, I think it's time we took it to the next level. Being the little guy puts us at a capital disadvantage but our weakness is also our greatest virtue. A corporate product rollout is a very stiff thing. These guys have so much money dedicated to administrative costs, advertising, et cetera. They don't market what they can't mark-up. They build in vast quantities, according to regimented schedules, for a fixed release date. They don't like to update an existing product while they have stockpiles of it waiting to be sold to distributors. The need to maximize profitability is their bottleneck. A cottage-made IEM, made with quality materials, still has David's chance against Goliath.
post #122 of 2208
maybe somebody can try doing a dual driver IEM, and use a 3-wire cable (high, low, gnd). You can try the soft ribbon cable currently being used on Stax-001's. This will allow the cross over to be moved outside of the mold.

Then you can use whatever film cap that suits your fancy, or run an active bi-amp XO.
post #123 of 2208
Thread Starter 
Did Popular Science actually X-ray the UE-11? Check it out.
How It Works: The Littlest Subwoofer | Popular Science

Westone decides to take it all off.
http://lib.store.yahoo.net/lib/yhst-...01758/w3p1.jpg
post #124 of 2208
Thread Starter 
Quote:
Originally Posted by AudioCats View Post
maybe somebody can try doing a dual driver IEM, and use a 3-wire cable (high, low, gnd). You can try the soft ribbon cable currently being used on Stax-001's. This will allow the cross over to be moved outside of the mold.

Then you can use whatever film cap that suits your fancy, or run an active bi-amp XO.
This is an interesting idea. I considered the possibility of wiring each driver separately so that a less-compromised crossover could be implemented. I think it's an idea worth serious consideration.
post #125 of 2208
Thread Starter 
WESTONE 3 CROSSOVERS - PHOTOS

http://www.head-fi.org/forums/f103/w...embled-413581/

It's discreet but it's a true 3-way xo. All hail Westone!
post #126 of 2208
Thread Starter 
OKAY, LET'S GET STARTED - EL CHEAPO (BILAVIDEO 1)

Quote:
INTRO
My wife is giving me grief about the mess of parts and tools sprawling across our dining table a/k/a my "lab." The WAF of the mess rates to about 0, so while I'm waiting for the crossover caps and some more TWFKs, I'll go ahead and get started with the simple stuff.
I'm going to be building a single-driver IEM using the cheapest drivers available, the BK26824, which is available through Mouser for $18.84/driver knowles acoustics, from Digikey for $18 even SPEAKER Z=29OHMS SS PORT ON END - BK-26824-000 and from IHI Electronics IHI Electronics - Parts Catalog - Part Detail - BK-26824-000 (price unknown), Global Spec Part Number BK-26824-000 from Knowles Acoustics and Newark KNOWLES ACOUSTICS|BK-26824-000|Speaker | Newark.com for the amazingly low price of $13.23 (if you're willing to wait the lag time for them to order it from KA).

Whatever the case, this is a very inexpensive driver. I got a pair from Mouser, which is often the least expensive source, but I could have saved a buck by buying from Digikey. I'm not suggesting it's the best driver you can buy, just that it's the cheapest and a great place to start for getting your hands dirty and your feet wet.

KA has a dozen drivers in the BK series, the last five of which (including the 26824) don't have a datasheet with specs. Like most of the BK drivers, the 26824 has a sensitivity of 118. It has a nominal impedence of 16 ohms, but its specific impedence depends on the frequency. It's 16 ohms at 500 Hz but 29 ohms at 1 kHz. The frequency response graph looks identical for the seven BK drivers listed. Here's what it looks like: http://www.knowles.com/search/prods_...-21600-000.pdf

This is going to be a very loud driver, one with very forward mids, at least undamped. Here are some quick stats:

200 Hz - 106 dB
500 Hz - 107 dB
900 Hz - 115 dB
1.5kHz - 125 dB
2.0kHz - 117 dB
2.5kHz - 123 dB
3.0kHz - 115 dB
3.5kHz - 122 dB
4.0kHz - 105 dB
5.0kHz - 107 dB
6 kHz - 10 kHz - nothing

There are three frequency peaks, one at 1.5kHz (125 dB), one at 2.5kHz (123 dB) and a third at 3.5 dB (122 dB). Given the almost 20 dB difference between bass and the midrange peak, as well as the 14 dB drop from 3.5 kHz to 5 kHz, this is clearly a driver that likes the midrange, which is where you'd expect a driver for a hearing aid, given the frequency pitch of human speech.

But what if we could match it with the right filter? Would it help? Could we take the cheapest, crappiest, driver on the market and turn it into something halfway decent?

It's time to find out. For the sake of convenience, I'm going to:

1) Solder these bad boys to the ends of a Westone replacement cable;
2) Add a dab of hot glue to help protect the leads from getting yanked off; and
3) Pop these INTO a pair of medium cushions (my size) for deep inner-ear fit UNDAMPED.
4) Experiment with the following filters:[indent]680 ohms - white[indent]1000 ohms - brown[indent]1500 ohms - green[indent]2200 ohms - red[indent]3000 ohms - orange[indent]4700 ohms - yellow
5) Report and document the results. It may well be that with the right filter, this could be a fun single driver. It may also be that with the right filter, this could at least be a useful driver in a multi-driver configuration.

Pictures will follow.
post #127 of 2208
Quote:
Originally Posted by Bilavideo View Post
This is an interesting idea. I considered the possibility of wiring each driver separately so that a less-compromised crossover could be implemented. I think it's an idea worth serious consideration.

if budget allows, you can also use a whole 001 cable per side (6 wires total) and do a tri-driver (2 wires per driver, no shared wires).

too bad the cable has to be extremely flexible in an IEM. solid core silver is out of the question
post #128 of 2208
I think the photos above show the crossovers are real but still as Bill points out whats the point of a cross over if you pull a bose over people's eyes. Good luck with the project.
post #129 of 2208
Quote:
Thank you for the words of support. You made my day.
My pleasure Bilavideo

Quote:
Originally Posted by Audiocats
imaybe somebody can try doing a dual driver IEM, and use a 3-wire cable (high, low, gnd). You can try the soft ribbon cable currently being used on Stax-001's. This will allow the cross over to be moved outside of the mold.

Then you can use whatever film cap that suits your fancy, or run an active bi-amp XO.
Hmmmm......This may open up a whole new genre of custom/cottage/boutique equipment if a modular approach is taken. Customized passive XO modules that can be plugged in, multi channel amps piggybacking active XO modules, DSPs, etc. You can build/buy/match the rig of your dreams and means.....

You might want to consider this if you ever go down the commercial offering route. It might just be the next big thing!!!

My 2cents worth
post #130 of 2208
Thread Starter 

This is the first batch, with the drivers inside the eartips. You find the size of eartips that fit your ears, then you solder the drivers to a decent replacement cable and put the drivers into the tips. This is fairly simple and economical. I like to use a little hot glue to help anchor everthing so the wires don't pull out the leads.

 


Edited by Bilavideo - 1/9/11 at 11:52am
post #131 of 2208
Thread Starter 

This is an early version, which I had to resolder because I had too much extra wire. The in-the-tip design is great, because it puts the drivers right into your ears. The foamies are also good for attenuating wild treble before you apply filters. It's not a good design if you want to add a lot of drivers. Things get bulky fast, which is why we see so many ITE-style shells.

 

 

The picture is dead.  Just use this link to see all the pictures I have in the album (I'm too lazy to play mix and match right now): http://www.head-fi.org/gallery/album/view/id/7525/user_id/71417


Edited by Bilavideo - 1/9/11 at 11:43am
post #132 of 2208
Thread Starter 

This is the CI-22955, a real workhorse driver capable of producing a wide range of frequencies, including quite decent bass. I was really impressed at how good these sounded, even before I started experimenting with filters.

 

 

The picture is dead.  Just use this link to see all the pictures I have in the album (I'm too lazy to play mix and match right now): http://www.head-fi.org/gallery/album/view/id/7525/user_id/71417


Edited by Bilavideo - 1/9/11 at 11:43am
post #133 of 2208
Thread Starter 

These are the TWFKs, the tiny little dual drivers (the world's smallest duals). As you can see, these would fit quite easily into an eartip to create instant "dual drivers." A pair of them would also create an instant "quad."

 

 

The picture is dead.  Just use this link to see all the pictures I have in the album (I'm too lazy to play mix and match right now): http://www.head-fi.org/gallery/album/view/id/7525/user_id/71417


Edited by Bilavideo - 1/9/11 at 11:43am
post #134 of 2208
Thread Starter 

Here's my first attempt at a triple, an in-the-ear triple. Without earshells to house the drivers, there's only so much room in the eartips. This first attempt at getting it all into the eartip was successful, and with the addition of an additional TWFK, I think it's also possible to up the ante to a "quint" (five-driver-setup). Beyond that, there just isn't enough space in the eartip to keep plugging in drivers, which is why I'm working on some plastic shells to house more drivers and some semblance of a crossover.

The one nice thing about this makeshift setup is that it's relatively easy to apply the filters.

 

 

The picture is dead.  Just use this link to see all the pictures I have in the album (I'm too lazy to play mix and match right now): http://www.head-fi.org/gallery/album/view/id/7525/user_id/71417


Edited by Bilavideo - 1/9/11 at 11:44am
post #135 of 2208
This is so epic
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