Home-Made IEMs
Feb 9, 2020 at 4:57 PM Post #11,012 of 16,258
Hey. I've been trying to decide upon which midrange driver to use in combination with SWFK-32254-000.
Either the ED 29869 or 28UAP01.
Has anyone utilized them in said config, or has general experience with either driver? My low-end driver would be a Tesla driver, 8mm, from 0Hz-180Hz, optimally. 904c6c4.png
 
Feb 11, 2020 at 4:21 PM Post #11,014 of 16,258
Back to vent holes guys. Would you recommend drilling them through the shell next to the tubes? How about in one of the tubes themselves? Seems like this may be easier to execute more consistently and will prevent the vent from clogging (ear wax etc), but I am sure there would be acoustic reasons why it’s not a good idea. Thoughts?
 
Feb 11, 2020 at 6:43 PM Post #11,015 of 16,258
I think you can use both. The one on the left is full until the second bend that´s where you cut anyways. The seal happens below that point so i don´t see any problem with the impression.

Can anyone tell me why my RC lowpass filter produces a result like that?
Below you see the yellow line which is a highpass. The same driver just with the capacitor and resistor switched results in the green line.
R=1kOhm C=4,7uF so cutoff should be somewhere between 30-50Hz.
RC lowpass.PNG

Edit: Nevermind! Stupid me put a 103 smd resistor in (10kOhm) which results in a 3Hz cutoff frequency. But still it is weird that there is so much high frequencys coming through.
Try increasing cap and reducing resistor for better result. The resistor also works as an attenuation system also
 
Feb 11, 2020 at 10:14 PM Post #11,016 of 16,258
Try increasing cap and reducing resistor for better result. The resistor also works as an attenuation system also
Hey yes, i tried that as well and you are right it works much better. Im ordering new capacitors with 100uF so i can use a smaller resistor. Im also ordering some smd inductors from which i know are traditionally not used with BA drivers but i figured its worth a try.
Another Question i wanted to ask is:
Do you guys use a compensation curve for measuring frequency response? There is something called open ear gain which is the natural resonance of the outer ear canal. In short it increases the area around 3khz. If you put a CIEM in your ear this effect wont take place and you need to compansate for that.
Im sure the most of you know this im just explaining because maybe there are a few who don´t know that.
Here is an extract of an wikipeadia article about this topic:

Insertion gain
The traditional method of real ear measurement is known as insertion gain, which is the difference between the sound pressure level measured near the ear drum with a hearing aid in place, and the sound pressure level measured in the unaided ear. First a measurement is made with the probe tube in the open ear (Real Ear Unaided Response, or REUR), then a second one is made using the same test signal with the hearing aid in place and turned on (Real Ear Aided Response, or REAR). The difference between these two results is the insertion gain. This gain can be matched to targets produced by various prescriptive formula based on the patient's audiogram or individual hearing loss.[9]

Another interesting read: Article

052515sonicslide18fig1.jpg

I know a audiogolist who can measure the real ear with an in situ microphone. Wouldn´t it be possible to measure someones ear and take that curve to compansate in ARTA. You could than presumably achieve a more flat/linear response?
 
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Feb 12, 2020 at 3:44 AM Post #11,017 of 16,258
Hey yes, i tried that as well and you are right it works much better. Im ordering new capacitors with 100uF so i can use a smaller resistor. Im also ordering some smd inductors from which i know are traditionally not used with BA drivers but i figured its worth a try.
Another Question i wanted to ask is:
Do you guys use a compensation curve for measuring frequency response? There is something called open ear gain which is the natural resonance of the outer ear canal. In short it increases the area around 3khz. If you put a CIEM in your ear this effect wont take place and you need to compansate for that.
Im sure the most of you know this im just explaining because maybe there are a few who don´t know that.
Here is an extract of an wikipeadia article about this topic:

Insertion gain
The traditional method of real ear measurement is known as insertion gain, which is the difference between the sound pressure level measured near the ear drum with a hearing aid in place, and the sound pressure level measured in the unaided ear. First a measurement is made with the probe tube in the open ear (Real Ear Unaided Response, or REUR), then a second one is made using the same test signal with the hearing aid in place and turned on (Real Ear Aided Response, or REAR). The difference between these two results is the insertion gain. This gain can be matched to targets produced by various prescriptive formula based on the patient's audiogram or individual hearing loss.[9]

Another interesting read: Article

052515sonicslide18fig1.jpg

I know a audiogolist who can measure the real ear with an in situ microphone. Wouldn´t it be possible to measure someones ear and take that curve to compansate in ARTA. You could than presumably achieve a more flat/linear response?
Nuraphone
With internal mic

It does the same thing
 
Feb 12, 2020 at 8:46 PM Post #11,019 of 16,258
Ah cool, so it is viable. Are you using the Harman curve to compensate? If yes where do I get it?
Its a headphone which uses a mic to measure your ear canal resonance and hair cell low sensitive region of frequency and tune headphone according to that

You can find the patent

Search nuraphone headphone on google
 
Feb 13, 2020 at 12:47 AM Post #11,021 of 16,258
Guys, tell me if the Assembly uses a driver with a vented hole, whether you need to drill compensation holes in the earphone case, if so, what diameter.

Depends on which driver you're using. If it's a BA then probably not. If it's a dynamic then yes.
 
Feb 14, 2020 at 11:25 AM Post #11,023 of 16,258
Its a headphone which uses a mic to measure your ear canal resonance and hair cell low sensitive region of frequency and tune headphone according to that

You can find the patent

Search nuraphone headphone on google
You are not reading my comments correctly :dt880smile:.
I found the .txt file for the Harman target response curve. Now I can use it as an compensation curve in ARTA.
Thanks anyway!
 
Feb 14, 2020 at 12:50 PM Post #11,024 of 16,258
You are not reading my comments correctly :dt880smile:.
I found the .txt file for the Harman target response curve. Now I can use it as an compensation curve in ARTA.
Thanks anyway!

Personally I wouldn't do that since the Harman curve is a subjective curve (using it as reference is fine IMO). I would listen to the IEM while making it and see what is my own preferred curve.
 
Feb 14, 2020 at 12:53 PM Post #11,025 of 16,258
Personally I wouldn't do that since the Harman curve is a subjective curve (using it as reference is fine IMO). I would listen to the IEM while making it and see what is my own preferred curve.
Yes ofc, but it is the most scientific thing to a "flat" response that there is. So that is a good starting point. Unless you tell me it's not.
 

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