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Home-Made IEMs - Page 6

post #76 of 1661
Thread Starter 
A FEW (ANGRY) WORDS ABOUT IEM CROSSOVERS

I don't want to belittle all the glamor and mystery being sprinkled and shoveled to the public, but here it is: The "integrated crossovers" referred to in ad after ad are mostly for show. By far, most of the frequency tuning is done mechanically, with filters. I was going to talk about this, using UE as a prime example, but held off out of concern that I'd so offend somebody at UE as to end up on the receiving end of major denunciations.

Then again, any denunciations would only disabuse my thoughts of any false conclusions. So, here's what I've found. Feel free to correct me where I err.

1. For all the talk about "integrated passive crossovers," most of these are token crossovers involving a single, low-cost cap, hooked to one wire going into one driver.

2. The driver being "crossed over" is usually the designated "tweeter."

3. Unlike serious crossovers in loudspeaker systems, none of the drivers used are specialized drivers. The "tweeter," "midrange," or "woofer" is a wide-range driver. In the loudspeaker world, the only manufacturer I can think of with the brass balls to market wide-range drivers as either woofers or tweeters is Bose. I'm not a Bose hater, but I priced the sats in Bose's $3,000 system, the one with pairs of mid/tweets arranged along room corners - with one driver directly at the audience and the other aimed at the ceiling or wall - and their replacements were something like $3/driver. Even Bose's subwoofer substitute consists of a set of cheap wide-range speakers, crammed into a box with various bafflings and then crossed low enough to produce an acceptable mid-bass.

4. Lacking specialized drivers, the best an IEM driver can do is employ a combination of crossover, acoustic filtering and tube tuning to produce the psychoacoustic sensation of "powerful bass." The same holds true of the "tweeters" - none of which are reliable past 7 kHz. You'll get some drivers which can push something into 10 kHz, but it's nothing like 100% and anything promised beyond that is blue smoke and mirrors.

5. On most systems, the "crossover" claim is puffery bordering on outright fraud. Where, in the audio world, would anybody brag about a "crossover" that only affected one driver, the "tweeter," and which then had to be supplemented by various filters? If these "crossovers" are any good, why aren't they employed with the midrange and woofer? How are those drivers being tuned, and if it's really just the filter at work, why do we need a "crossover" for a "tweeter" that isn't really a tweeter and is clearly capable of handling the same signal being sent to the other drivers?

6. There ARE exceptions, though by how much is anybody's guess. The UE 10 and UE 11 wire up more than one driver. The UE 11, in fact, has the most sophisticated crossover - an SMD capable of handling up to four separate frequencies. And why? Because the UE 11 employs four drivers, the last of which is its "subwoofer." Even then, we are taking about first-order crossovers of the simplest design, really nothing to write home about.

WHAT I LEARNED ABOUT UE FROM ITS OWN WEBSITE

(Note: This is not intended as an expose aimed at UE so much as a heads-up regarding what the entire industry is doing. To its credit, UE's top customs push the industry to do better.)

Please understand that I am not here to knock UE, the famed pioneer in selling custom-fit, professional monitors to the consumer. I'm just saying that most of the talk about "crossovers" is hype, and that if most consumers were willing to take the time, they'd discover what I've discovered. Understand that I'm not here to run anybody down. I just have my own agenda, which is to make my own in-ear monitors from scratch. I don't feel like paying these companies their mark-up. I feel like I can do as well or better on my own, even if I've come late to the game and have to learn all this stuff on my own.

What I'm going to show you involves UE because UE at least made it possible for consumers to figure things out for themselves. Most manufacturers do a pretty good job of hiding how things really work. In showing off, UE may have shown too much. Who am I to complain?

UE has a pretty complicated product line, with four series of earphones (Metro, Super Fi, Triple Fi and Custom). In addition, there's no attempt at symmetry within these lines. Unlike Westone, which has four universals and four matching customs (though it doubles the top universal - UM3 - into the W3 and the UM3X while doubling the bottom custom - ES1 into the ES1 and CR1) UE is all over the place. They have something like 4 metros, 8 super fi's, 2 triple fi's and five customs - three of which are practically the same earphone. It's a mess. It looks like Apple before it took Steve Jobs back.

If we look carefully at that product line, certain details and patterns emerge. All of the metros are dynamic drivers. Of the 8 super fi's, only the Super Fi 5 Pro claims to have a "crossover," but what it shows on its diagram looks less like a crossover than an O-ring (haha). http://www.ultimateears.com/_ultimat...o_features.php

In fact, this looks like the "low frequency diaphragm for deep rich bass" displayed in the diagram for the Super Fi 5eb. http://www.ultimateears.com/_ultimat...b_features.php

It gets weirder. UE trots another mysterious "crossover" on its Triple Fi 10. Look at this diagram and what you'll see looks suspiciously like another mechanical device being fobbed off on the public as an "integrated passive crossover." Well, if it does the job, all power to UE, but it's not what people think of as a crossover. But judge for yourself: http://www.ultimateears.com/_ultimat...o_features.php

The first actual picture of something that, to me, looks like an actual electrical crossover is the SMD shown in the diagram for the UE4: http://www.ultimateears.com/_ultimat...tom/ue4pro.php

But look at the fine details. I realize this is a diagram, not a photo, but if you increase the magnification of your screen (from 200% to 400%), you'll notice that this crossover is only serving one driver, the dedicated "tweeter."

Take a look at the UE5 and tell me if it doesn't look like the same arrangement: http://www.ultimateears.com/_ultimat...o_features.php

Now look at the UE7 and tell me what you see: http://www.ultimateears.com/_ultimat...o_features.php

I see one crossover serving what looks to be one driver. It can't be the same crossover serving both drivers, even if you'd like to imagine that little yellow wire heading over to the other driver. What would be the point of having three drivers use the same crossover setting?

It's not till we get to the $900 UE10 that we see a crossover that looks like a real crossover.
http://www.ultimateears.com/_ultimat...o_features.php

Even then, this three-chip crossover is only wiring two drivers. Check the leads. The second driver is a "dual driver" giving the UE10 its status as a "triple driver" phone. But there's only one set of leads for that "dual driver" so the real basis for separate "low and midrange frequencies" is the use of different acoustic filters. To its credit, the UE 10 uses a dual driver with dual sound outlets, something the TWFK doesn't do. This allows the two drivers to have different filters. But let's not kid ourselves about the "crossover." This triple-driver only has two crossover settings - at least electronically.

Now, look at the UE11, the top of the heap at Ultimate Ears and quite possibly the closest thing the earphone world has to a decent crossover: http://www.ultimateears.com/_ultimat...o_features.php

Magnify it well and you'll see that we now have three sets of wires to feed "four" drivers. It has a separate tweeter, a separate midrange and a "dual driver, subwoofer." That "dual driver" is UE's version of the TWFK. To provide a real crossover to these three transducers, UE has broken down and purchased a multilayer SMD, one capable of handling up to four separate circuits.

As far as I'm concerned, this is the only real crossover out there. Everything else is just hype. Try walking into an audio forum and claiming you have an "integrated passive crossover" but it only works with your tweeter, which isn't really a tweeter, just a wide-range driver you've decided to use as a tweeter. They'll ask you how long you've been working for Bose.

(Note: That last jibe at Bose has to do with the company's Herculean efforts to make mediocre materials sound good, which I think they pull off successfully. In point of fact, Bose uses much more sophisticated crossovers than are found in any IEMs on the market.)
post #77 of 1661
FYI Bilavideo, the links to ultimateears.com in your post above are broken.
post #78 of 1661
Thread Starter 
Crap. Thanks for the FYI. I'll see what I can do to fix it.
post #79 of 1661
Thread Starter 
The links are fixed. I hope this helps others look carefully at how these crossovers are wired up and compare the various definitions of crossover being used.
post #80 of 1661
Bilavideo, who makes this multilayer SMD? Vishay or is it custom?
post #81 of 1661
I also subscribed to this thread... by the way... could we be discovering here many secrets of manufacturers who say they use in house made components? Some drivers presented here are not new to me... like...[]
post #82 of 1661
Quote:
Originally Posted by vhbaske View Post
I also subscribed to this thread... by the way... could we be discovering here many secrets of manufacturers who say they use in house made components? Some drivers presented here are not new to me... like...[]
well i would understand if people are using standard components, like Westone uses the 22955 in their ES3X as their low frequency driver. But Westone uses custom drivers/receivers for their mid and high, because nothing fits what they want. But defs, i would like to see what Earsonics uses for their Universal and custom monitor...i own the Sm2 from Earsonics...but nooooo way am i taking that apart =)
post #83 of 1661
Hi mate, I'm just curious to know how you can place so much stock in diagrams? If they were actual pictures, trust me I'd be behind you 100% but, as far as diagrams are concerned, I normally take them with a grain of salt.

I think your absolutely right about the fact that there are no dedicated iem drivers that act as tweeters, subs etc... I figure the only way to have a real dedicated system would be to mix BA and Dynamic armatures. So think of IE8 + ER4P as a good mix for a sub + high end and maybe throw in something as a dedicated midrange driver.

Don't forget that filters are just caps built into a circuit as high or low pass filters so that the iems become dedicated frequency drivers (not really cross over as they make us think) and then your right that the cross over part comes from mechanically mixing the sound together.

I dunno, are there any high end custom head-fiers out there with some nice cameras who can take pics of their UE's so that we can check those pics instead of the diagrams on ue's website? For all we know the cross over may not even have any actual wires.
post #84 of 1661
Thread Starter 
Quote:
Originally Posted by WalkGood View Post
Bilavideo, who makes this multilayer SMD? Vishay or is it custom?
They're not custom. Take a look at this. Products: Ceramic Capacitor Overview

Vishay also makes them.
post #85 of 1661
Thread Starter 
Quote:
Originally Posted by pdupiano View Post
Hi mate, I'm just curious to know how you can place so much stock in diagrams? If they were actual pictures, trust me I'd be behind you 100% but, as far as diagrams are concerned, I normally take them with a grain of salt.
To be sure. These are diagrams, not photographs. Still, the diagrams are telling.

There are limits to what you can take away from a mere diagram. But when a manufacturer shows you a diagram of its layout, one specifically identifying its crossover, and that crossover (in most cases) fits the profile of a rectangular-shaped tantulum SMD and is only wired to one driver, specifically identified as the tweeter, it's worth taking note of.

Now, for the casual observer, that diagram is pretty impressive. It looks high tech. It's a salesman's wet dream, a color-coded display of all the ingredients that go into these wonderful earphones. I mean, look at the Mona Lisa and smile: They've got multiple drivers, filters, crossovers, you name it. The point of the diagram is that these aren't just speakers with wires soldered into them.

But in order to make the diagram, somebody had to know what to illustrate. We know the drivers are accurately reproduced, as are the filters. The rectangular boxes, representing the crossovers in most of the diagrams, match up with SMDs, which is what one would use for a low-voltage capacitor in something this small. I'm prepared for the possibility that there's more to the wiring than depicted here, but I'd be at a loss for why they would fail to give themselves less credit than they already do. The SMDs shown in most of the diagrams are not capable of handling multiple frequencies. They're simply very small caps. In most of the diagrams, a single SMD is connected to one driver, which is at it should be.

What's more telling is that there aren't multiple SMDs connected to multiple drivers. If they can show you and take credit for one, they could show you and take credit for two, or three. Until we get to the UE 10, it's a single SMD connected to a single driver, and that driver is always the tweeter. When we get to the UE 10, the diagram changes. We get a more complex arrangement, probably a multilayer capacitor array. This diagram is quite different from the others. It has three capacitors positioned on a small PCB. What's more, unlike the crossovers in the other phones, this one is clearly wired to more than one driver.

I admit, I'm taking UE at its word - or in this case, its diagrams. As you move up the product line, we go from nothing, to very simple crossovers, to more complex ones. It's not till we get to the UE 11 that we get a crossover with three sets of wires connecting it to three different drivers. There may be more to this picture than meets the eye, but what I see is good enough for me.
post #86 of 1661
Thread Starter 
Hey, Pdupiano, I hope that last post didn't come across as defensive. I'm making a case. That doesn't mean what you've said isn't also legitimate. In the end, we are just talking about diagrams. It's just that, after looking hard at those diagrams, I think UE has unwittingly admitted more than perhaps it ever wanted to. ;-)
post #87 of 1661
Thanks for sharing what you've been learning about IEMs! I found post #76 very interesting.

I'd like to suggest the idea of capturing and embedding those diagrams in the text. I know that's asking a lot, so I'm not even asking. It's just an idea, as those diagrams and links won't last forever.
post #88 of 1661
Nah don't worry about it, but I still think it would be really nice if any headfier with a ue pro 11 took some uber close-up shots. I can certainly see where you're coming from, but dont forget, most people who draw diagrams professionally arent always the engineers nd are therefore left to their own interpretations of how the think things function.
post #89 of 1661
Quote:
Originally Posted by pdupiano View Post
Nah don't worry about it, but I still think it would be really nice if any headfier with a ue pro 11 took some uber close-up shots. I can certainly see where you're coming from, but dont forget, most people who draw diagrams professionally arent always the engineers nd are therefore left to their own interpretations of how the think things function.
Well, lets hope someone takes some photos so we can finally solve this problem =)
post #90 of 1661
Thread Starter 
I agree. We should enlist the aid of a headfier with customs.
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