[markot86]

I see that the UM2's boast that they have this feature; What exactly is it?

 

[mrarroyo]

You may want to read: http://www.termpro.com/articles/xover2.html

 

[DJGeorgeT]

it performs the function of a crossover without requiring external dc power. In other words, only passive electronic devices such as resistors, capacitors and inductors are used instead of Op Amps for low pass filtering, high pass filtering and/or bandpass filtering.

 

[kramer5150]

unpowered RLC circuit. In-line between amplifier and speaker/driver.
Used to attenuate highs, lows or both.

Garrett

 

[wualta]

I don't own an in-ear (IE) type 'phone, so when I saw your question I did a little googling to see how the heck a crossover circuit could possibly have application to a tiny single (I thought) driver. Turns out someone started the ball rolling by actually making a two-way IE phone, and others have followed. I still don't know why they'd need a separate "woofer" and "tweeter", but I can easily imagine the engineering for IE phones is different from any other type, so I'll give whoever came up with it the benefit of the doubt on this one. Power handling, maybe.

 

[markot86]

so basically, any multi driver IEM must have this feature, is that correct?

 

[wualta]

Not must, necessarily, but it's bloody likely if the design engineer wants to carefully control where one driver leaves off and the other begins and the relative levels of the two [read: "voicing"].

 

[DJGeorgeT]

Quote:

Originally Posted by markot86 so basically, any multi driver IEM must have this feature, is that correct?

yup in the UM2, two drivers are used in each ear. It uses a 2-way xover to serve two drivers. One driver handles the treble as well as a portion of the mids, and the other handles the rest of the mids and bass. You see this done with speakers. Westone also makes the ES3 with a three-way crossover to handle the highs, mids and bass separately.

 

[kramer5150]

Quote:

Originally Posted by markot86 so basically, any multi driver IEM must have this feature, is that correct?

Passive crossovers are not MUST have. Speakers themselves have frequency response limits, and will naturally "roll off" their output near those extremes.

The problem:

Speakers (be it loudspeaker or headphone) can produce sound WELL beyond their intended frequency bandwidth. Unfortunately their output at those extremes is usually harmonic overtones, filled with distortion, and other resonant artifacts. Hence the driver tends to color the sound and the fundamental note. Thats where passive filters come in to attenuate those extremes.

Tweeters and high frequency drivers DO need a high pass filter in line for loud music.

Garrett

 

[DJGeorgeT]

Quote:

Originally Posted by wualta I still don't know why they'd need a separate "woofer" and "tweeter", but I can easily imagine the engineering for IE phones is different from any other type, so I'll give whoever came up with it the benefit of the doubt on this one. Power handling, maybe.

Because it is not easy to design/tune a speaker/driver to sound a particular way without tradeoff. A single driver may give you excellent highs, but poor low end response or viceversa. Being able to xover makes the design job a lot easier and also improves the sound at the end. The sound can be manipulated easily with no tradeoff and the frequency response can be extended easily. You would not use a subwoofer for highs...dedicated components can be used with the help of a crossover....a driver that is good for highs, but lousy for lows can be used solely for the highs. A driver that is lousy for the highs, but excellent for low end can be used solely for the bass. The end result is also an increase in headroom.

 

[El nai del vent]

Hello.

I am in the project of replacing the baby advent speaker crossovers. The woofers are replaced with new production ones. And I wonder... how do I choose the specifications of the capacitors and inductors in terms of micro-farads and millie-henries? What parameters should I take as reference?

 

[Sazalirazak]

I use passive crossovers to direct <50hz to 2 mono subwoofers