Bought an IEC711 coupler, what should I know?

[FireLion]

Bought a 711 clone, they include Arta software.

I want to measure iems and headphones. More specifically to measure differences when I mod something or assemble a prototype.

Question: What should I learn to get the best from it.

I will probably make a follow up purchase for the silicone ear and plate. Not sure if there is a homebrew setup that also work for me, that I could combine with the coupler. Something to place the headphones on.

 

[staticV3]

Don't use the provided cal file, it's no bueno.
If you want to get your measurements closer to a genuine GRAS ra0045, then take a look at the ER2SE Tour kit organized by csglinux (Link)

To give you a rough idea, here's how my 711 clone compares to the real deal:

This is without any cal file. Just raw response vs raw response.
The one IEM with bass roll off got damaged somewhere along the way. That's not the coupler.

When measuring IEMs, use blu-tac to fix the IEM to the steel tube, that way you avoid rocking modes in the IEM housing:


A popular setup is to use the Apple dongle as both DAC and ADC.
One issue that can arise is that some 711 couplers have an impedance close to the volume down button on inline remotes.
The result: https://cdn.discordapp.com/attachme.../1001198508411465879/VID_20220725_145215.webm
Obviously that isn't a problem with normal interfaces.

For measurements, the volume reference is 94dBSPL. That's most likely a good bit louder than your listening volume.
Don't worry, the IEMs can take it. Plus, it helps increase the measurement SNR as 711 clones often aren't very quiet.

Over-ear is a big can of worms. If you want to match the acoustic impedance of a GRAS 45BC/45CA to get results that are compatible with the Harman OE target, then your best bet is the new KB5000 clone from Sounds Good Store (Link).

To measure mod differences, a pinna-less flat plate setup is usually good enough, just keep in mind that it'll underestimate pad leakage.

 

[Blorg]

One issue that can arise is that some 711 couplers have an impedance close to the volume down button on inline remotes.
The result: https://cdn.discordapp.com/attachme.../1001198508411465879/VID_20220725_145215.webm

I sometimes have this issue measuring, when putting the IEM in or out, and had no idea what was causing it, that is interesting.

 

[gcompari]

Don't use the provided cal file, it's no bueno.
If you want to get your measurements closer to a genuine GRAS ra0045, then take a look at the ER2SE Tour kit organized by csglinux (Link)

To give you a rough idea, here's how my 711 clone compares to the real deal:
View attachment 271269
This is without any cal file. Just raw response vs raw response.
The one IEM with bass roll off got damaged somewhere along the way. That's not the coupler.

When measuring IEMs, use blu-tac to fix the IEM to the steel tube, that way you avoid rocking modes in the IEM housing:
View attachment 271270

A popular setup is to use the Apple dongle as both DAC and ADC.
One issue that can arise is that some 711 couplers have an impedance close to the volume down button on inline remotes.
The result: https://cdn.discordapp.com/attachme.../1001198508411465879/VID_20220725_145215.webm
Obviously that isn't a problem with normal interfaces.

For measurements, the volume reference is 94dBSPL. That's most likely a good bit louder than your listening volume.
Don't worry, the IEMs can take it. Plus, it helps increase the measurement SNR as 711 clones often aren't very quiet.

Over-ear is a big can of worms. If you want to match the acoustic impedance of a GRAS 45BC/45CA to get results that are compatible with the Harman OE target, then your best bet is the new KB5000 clone from Sounds Good Store (Link).

To measure mod differences, a pinna-less flat plate setup is usually good enough, just keep in mind that it'll underestimate pad leakage.

I'm interested in a IEC 711 clone coupler: do you know a good one at a reasonable price?
What about "phantom power"? Do these clones use external polarization? Can I use a Topping E2x2 (48V) or RME BabyFace Pro (48V)?
If "cal. files" are bad, how can we correct the measurements?
Is Blu-Tac something like this: https://www.amazon.it/Originale-riutilizzabile-Adesivo-Bostick-Ufficio/dp/B0892V6S7R?
May you post a pic about the use of the Blu-Tac sealing IEM to 711?
What cable/connector do I need to use/realize to connect the coupler to the XLR mic. input of the ADC? BNC to XLR unbal./bal.?
Sorry for these very "basic" questions, but I newer used a coupler...

 

[staticV3]

I'm interested in a IEC 711 clone coupler: do you know a good one at a reasonable price?

Here are the two largest sellers of 711 clone couplers:

https://www.aliexpress.com/store/1101341729

https://www.aliexpress.com/store/1101358337

What about "phantom power"? Do these clones use external polarization? Can I use a Topping E2x2 (48V) or RME BabyFace Pro (48V)?

Some versions use Electret capsules that can be plugged into an audio interface via a Phantom Power to Plug-in Power adapter like the VXLR+.

Other versions use a microphone capsule that requires a B&K 1704 CCLD conditioner.

If "cal. files" are bad, how can we correct the measurements?

In my case, by comparing the same IEM units with identical insertion depth, once measured with a genuine GRAS or B&K coupler, and once with my clone coupler, then computing the response difference.

That's what the csglinux ER2SE tour is about.

A less accurate alternative is the 5128∆ initiative that's part of squig.link

Is Blu-Tac something like this: https://www.amazon.it/Originale-riutilizzabile-Adesivo-Bostick-Ufficio/dp/B0892V6S7R?

Yes, that's Blu Tack.

May you post a pic about the use of the Blu-Tac sealing IEM to 711?

Blu Tack doesn't seal, it just braces the housing to impede rocking moments:

What cable/connector do I need to use/realize to connect the coupler to the XLR mic. input of the ADC? BNC to XLR unbal./bal.?

Depends on the Mic capsule type.

 

[somebodyelse]

Blu Tack doesn't seal, it just braces the housing to impede rocking moments:

Is that to avoid the wiggle we often see in IEM response somewhere around 100Hz?

 

[staticV3]

Is that to avoid the wiggle we often see in IEM response somewhere around 100Hz?

Correct.

In-situ, your concha and pinna takes care of bracing the IEM housing, but on couplers and sometimes even full HATSs like the 45CA and 5128, additional support is needed.

 

[gcompari]

Here are the two largest sellers of 711 clone couplers:

https://www.aliexpress.com/store/1101341729

https://www.aliexpress.com/store/1101358337

Some versions use Electret capsules that can be plugged into an audio interface via a Phantom Power to Plug-in Power adapter like the VXLR+.

Other versions use a microphone capsule that requires a B&K 1704 CCLD conditioner.


In my case, by comparing the same IEM units with identical insertion depth, once measured with a genuine GRAS or B&K coupler, and once with my clone coupler, then computing the response difference.

That's what the csglinux ER2SE tour is about.

A less accurate alternative is the 5128∆ initiative that's part of squig.link


Yes, that's Blu Tack.


Blu Tack doesn't seal, it just braces the housing to impede rocking moments:
View attachment 444981


Depends on the Mic capsule type.

The first one

https://www.aliexpress.com/store/1101341729

I can see that it works with phantom power less than 10V, so is it impossible to use it with Topping E2x2 or RME BayFace Pro.

I own the Meizu HiFi DAC and the Meizu HiFi DAC Pro but I don't know what happens below 100Hz and above 10kHz with the ADC section of the Meizu devices: normally the mic/ADC section of these devices is very poor...

I can see the 3,5mm cable with TRS 3,5 plug: is it a fake unbalanced stereo connection or a balanced mono connection?

Is this

Amazon.it

a VXLR+ connector?

The second one

https://www.aliexpress.com/store/1101358337

comes with it's audio board, but I don't konw the ADC/DAC quality of this device: do you think it is OK?

 

[staticV3]

I can see that it works with phantom power less than 10V, so is it impossible to use it with Topping E2x2 or RME BayFace Pro.

It is possible to use it with Topping E2x2 or RME BayFace Pro, but only with an additional VXLR+ (or similar).

I can see the 3,5mm cable with TRS 3,5 plug: is it a fake unbalanced stereo connection or a balanced mono connection?

What cable?

Is this
Amazon.it a VXLR+ connector?

This is a VXLR+: https://www.google.com/search?q=vxlr+

The second one
https://www.aliexpress.com/store/1101358337 comes with it's audio board, but I don't konw the ADC/DAC quality of this device: do you think it is OK?

I don't know.

 

[gcompari]

It is possible to use it with Topping E2x2 or RME BayFace Pro, but only with an additional VXLR+ (or similar).


What cable?


This is a VXLR+: https://www.google.com/search?q=vxlr+


I don't know.

Sorry for my late answer...

The cable is bundled with this IEC711 coupler:

https://it.aliexpress.com/item/4000789796521.html

I attach the cable picture: does work this cable with the VXLR+?

I found the Rhode VXLR+ connector: thanks. I'll buy it.

I can see that the adapter reduces 48V to a polarization compatible with the max 10V of the the IEC711 coupler mic. from the first link you posted: I think I'll buy it.

 

[staticV3]

The cable is bundled with this IEC711 coupler:
https://it.aliexpress.com/item/4000789796521.html
I attach the cable picture: does work this cable with the VXLR+?

Yes, it should work.

 

[gcompari]

Blu Tack doesn't seal, it just braces the housing to impede rocking moments:
View attachment 444981


Depends on the Mic capsule type.

What is the black rubber ring? I received may IEC711 coupler but it doesn't have any black rubebr ring: just metal...

 

[staticV3]

What is the black rubber ring? I received may IEC711 coupler but it doesn't have any black rubebr ring: just metal...

A custom-built fixture for consistent insertion depth IIRC. Not my pictures nor my fixture, so that's all I can say.

 

[Lykkedk]

I’m going to build a measurement flatplate rig.

Having this IEC711 coupler with the Røde phantom to 3.5mm. converter into —-> an 35dB phantom power mic. input unit (Cosmos APU)

This is working very well, with IEM’s, but I was wondering if it’s suited for an flatplate rig for overear headphones (Hifiman, KGC etc…)
I can calibrate to 94dB with my SPL calibrator.
I also have the Umik usb mic., but the mic. is to long to use without having it tilted.

The IEC711 is not very long so better suited for this project.

Anyone tried ?

Rgds; Jesper.

 

[staticV3]

I’m going to build a measurement flatplate rig.

Having this IEC711 coupler with the Røde phantom to 3.5mm. converter into —-> an 35dB phantom power mic. input unit (Cosmos APU)

This is working very well, with IEM’s, but I was wondering if it’s suited for an flatplate rig for overear headphones (Hifiman, KGC etc…)
I can calibrate to 94dB with my SPL calibrator.
I also have the Umik usb mic., but the mic. is to long to use without having it tilted.

The IEC711 is not very long so better suited for this project.

Anyone tried ?

Rgds; Jesper.

Measuring headphones on a 711 w/o artificial pinna makes little sense.

At that point, just use a simple flat plate setup with simple mic à la Solderdude for the lowest self-noise and distortion.

Frequency response data won't be terribly useful either way.

 

[Lykkedk]

Okay… thanks for answering.

I guess the same issues goes for the tilted umik on a flatplate without pinna then?

Jesper.

 

[staticV3]

I guess the same issues goes for the tilted umik on a flatplate without pinna then?

Correct.

If you're looking for useful absolute frequency response data, or you want to compare frequency responses between different headphones, then an artificial pinna + inner ear simulator is the only way.

 

[Lykkedk]

Okay, got it thank’s

Jesper.

 

[Lykkedk]

Hello…

So I mocked up a proto with artificial ears.
It’s not meassuring that bad for a start, and the results are not far away from what I can find around the net, comparing to my Hifiman HE400se (32ohm) and my AKG’s.
I did some aluminium work to create, so that the R side of the rig, can tilt out, creating more pressure on headphones.
It is still a proto.

Measurements are best when using a calibration file I made from an HE400se measurement I found on squid.link.

Jesper.

 

[Lykkedk]

I will be doing some experiments next few day’s.
I’m not sure howto create a better calibration than with the squid.link reference HE400se.

Is there some way better to do it?

Will post some measurements also here.

Jesper.