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Home-Made IEMs - Page 125

post #1861 of 6259

Interesting list! So my UERM is actually two way rather than the three way UE claims!

post #1862 of 6259
Quote:
Originally Posted by Xymordos View Post  Interesting list! So my UERM is actually two way rather than the three way UE claims!

 

Depends on how you want to define "way". The tweeters are run differently; one is run with zero-bias, the other is run with center-tap configuration, and the two seem linked in series to the same cap. In terms of passive components, it's two-way, but center-tap biases DC current differently, so it can be argued that it's three-way.


Edited by tomscy2000 - 6/24/14 at 9:21am
post #1863 of 6259

Wouldn't a series configuration mess up the phase?

post #1864 of 6259
Quote:
Originally Posted by CMOS1138 View Post
 

I am playing around with the knowles GQ-30783 driver today, I am getting a rather bright response from it with no damper and a tube length around 3 cm, I tested it with a tube length of around 7 cm and I liked that sound quite a bit but that is far to long of a tube to work in a shell. What damper should I use to get a similar response? I have 680 on hand but I will need to order anything else.

I'd say 3cm is very long, try going with 16mm and 1000 ohm damper

 

Quote:
Originally Posted by vector1 View Post
 

 

Interesting. I have tested with sine wave generators, and I can detect a very perceptible dip at the 1.8k-2k range when listening to just the CI/DTECs, so you're absolutely right.

 

I'm still awaiting the arrival of my WBFKs which I destroyed, but I think you're also right about WBFK not contributing to the 1-4k range.

 

I have made several modifications as you recommend, but why would you push WBFK to the back? 

 

Also,on further reflection I think there might not be space to squeeze the damper into the CI channel alone because I need at least 5mm, and I currently have around 2.5mm space, unless I lengthen the entire IEM which I'm trying not to at the moment.

 

Do you have any recommendations on a different driver that is suitable for the midrange?

 

Here is my latest set for testing now.

 

This is the drivers in the boot, WBFK moved back, widened the bore on DTEC and CI and prepared rubber plugs to hold the driver nozzles in place, made the inside a little smoother in case that affects the sound.

 

This is the exterior, as MuZo said, the nozzle ID is 2.2 and OD of 3.2.

 

Glad to hear it. Moving WBFK back will slightly change output and will also improve impulse time response.

 

ED or BK will work good on mids. ED will give brighter sound, BK will be more "sweet" and lush, probably you could try EF - I have no idea how it sounds though. vented type EF is a woofer in Audeo 232.

 

 

Quote:
Originally Posted by tranhieu View Post
 

The CI is very sensitive to dampening resistors, if it were me I wouldn't go as far as 40ohm, not only you are reducing its SPL but bass decay will also be significantly reduced as a result. 10-20ohm should be enough to keep it controlled without losing too much of its signature (personally I always stay within 13-18ohm). If it's still too loud vector might need to consider another driver as sub woofer.

I was working with CI on Sunday. 20 Ohm damper cuts off 2.5dB given that CI will be working with DTEC 40 Ohms is not that much, if both drivers are aligned in phase.

in phase: DTEC+CI = +6db increase

in phase: DTEC+CI+40 Ohm = +1dB increase.

The only question is what is the target - bass heavy or natural bass. The first will be bass heavy the second will be closer to natural.

 

Quote:
Originally Posted by vector1 View Post
 

I have several pots that I'm just tuning to find the right sound blindly :D

 

Currently I'm listening to the reversed arrangement (CI full range on resistor, DTEC on lowpass and it's pretty good!)

 

Could you suggest alternatives? I'm open to getting an alternative driver, and using either CI or DTEC as the woofer.

I'm glad you liked the design

 

Quote:
Originally Posted by vector1 View Post
 

 

I think 25 drivers will be kind of out of my budget haha!

 

What about the DWFK as a mid? I haven't see anyone use it yet.

I do have DWFK on my stock, but haven't got time to try it out, so I have no idea how it sounds. DWFK seems on paper as ideal full range dual driver. so probably it could be used for any frequency. Please note that since it's vented dual FK you probably won't be using it as tweeter.

DTEC + DWFK could be very fine set up.

 

Quote:
Originally Posted by Xymordos View Post
 

Wouldn't a series configuration mess up the phase?

It won't mess up but will change the phase quite a bit. Nothing that cannot be planned when designing an IEM.

post #1865 of 6259
Quote:
Originally Posted by tomscy2000 View Post
 

 

Depends on how you want to define "way". The tweeters are run differently; one is run with zero-bias, the other is run with center-tap configuration, and the two seem linked in series to the same cap. In terms of passive components, it's two-way, but center-tap biases DC current differently, so it can be argued that it's three-way.

They both are half wired.

 

Quote:
Originally Posted by piotrus-g View Post
 

 

I was working with CI on Sunday. 20 Ohm damper cuts off 2.5dB given that CI will be working with DTEC 40 Ohms is not that much, if both drivers are aligned in phase.

in phase: DTEC+CI = +6db increase

in phase: DTEC+CI+40 Ohm = +1dB increase.

The only question is what is the target - bass heavy or natural bass. The first will be bass heavy the second will be closer to natural.

 

Did you also compare the CSDs? On 10ohm bass decay reduction is very noticeable, 15ohm is clearly audible and on 20ohm it doesn't sound like the original CI anymore.

post #1866 of 6259
Quote:
Originally Posted by tranhieu View Post
 

 

 

Did you also compare the CSDs? On 10ohm bass decay reduction is very noticeable, 15ohm is clearly audible and on 20ohm it doesn't sound like the original CI anymore.

No I didn't but finial IEMs were not lacking bass at all. and the response (+TWFK) was actually pretty impressive.

post #1867 of 6259
Quote:
Originally Posted by tranhieu View Post  They both are half wired.

 

Hmm, you're right. I looked at it too quickly.

post #1868 of 6259

I seem to have encountered a problem with the CIs. The left channel seems to be buzzing in the mid bass region when the volume goes up, however I can't replicate this issue with the right channel even when i have switched every single component except the driver and connecting wires. It was not present earlier when I was testing it either to the best of my knowledge, and only appeared this morning.

 

Could I have accidentally damaged the CIs even when I'm not touching/playing music through it? It was fine last night, and this morning I suddenly noticed a intermittent buzz.

post #1869 of 6259
Intermittent? Good luck, could be anything. If it goes away then it's prolly not the driver. How are your receivers positioned, are they glued in place so that they don't vibrate against each other or the shell?
post #1870 of 6259
Quote:
Originally Posted by MIke M View Post

Intermittent? Good luck, could be anything. If it goes away then it's prolly not the driver. How are your receivers positioned, are they glued in place so that they don't vibrate against each other or the shell?

When I say intermittent I mean it only appears at the bass region of certain tracks, and is completely reproducible and gets worse with increasing volume, like greater distortion.

 

I haven't glued anything into place but the drivers are tightly packed against each other, so there's not much room to vibrate. It still occurs when I remove one side of the shell.

post #1871 of 6259
The drivers are mechanical, anything mechanical can fail. Usually when a driver fails (atleast what I've seen) they drop out or go low volume. If its not glued, I'd test the driver by itself without any resistors, then you'd know for sure
post #1872 of 6259
Depending on how it is setup, a CI will distort if over driven. If its not happening at normal listening volumes, then you are probably alright.
post #1873 of 6259
Quote:
Originally Posted by MIke M View Post

Depending on how it is setup, a CI will distort if over driven. If its not happening at normal listening volumes, then you are probably alright.

 

The trouble is that it only happens at one ear, and at normal listening volumes, and i have tested it full range without resistors and it's even more detectable.

post #1874 of 6259
Sucks, but it sounds like u may be buying another CI. I'd take it out and drive it by itself first though
post #1875 of 6259

Most likely that CI was shorted in the process. You'd be better off buying another one. 

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