[AtlanticProSnd]

  Here is a comparison of the U12 through two different output sources. One with a low output impedance (CHORD Mojo). And one with a higher output impedance (USBPre 2). Notice the seesaw effect between switching from one source to the other.
 
 
 

The USBPre2 is not designed for low impedance devices (Bad comparison)  Should have used Pro gear for this as that is what his claim is.  USBPre2 is a preamp not a amp and not designed for low impedance loads.  It's designed to drive an amp.  It does have a Phones out for non-critical monitoring however the design of this device is to drive an amp or mixing console input.
 
Quote:

  Some of our products, the 12's being one of them, were designed for stage and studio use. Live performace and studio gear typically have higher output impedances. Thus the 12's need a higher output impedance if you're searching for a more transparent sound signature. Forgive me if I sound redundant at times I just wanted to explain the effects of output impedance for everyone to understand. I hope this helps you guys achieve the sound signatures you search for
 
 

Not true at all.  I have worked in pro audio for 30 years and have NEVER seen any pro gear that has an output impedance higher then 2.5 Ohms (most are measured less then 1 ohm).
 

  I believe its very possible that many of you that say the A/U12's sound "veiled" and that the B1 module fixes the veiling issue are using a low output impedance amp/dac and are compensating with a B1 module to bring down the bass and low mids... Which is what the B1 module was designed for. Thus balancing out the inherent response of the A/U12's through a low output impedance amp. For those who believe the A/U12 sounds "veiled" with the S1 module simply changing over to a source with a high output impedance will give you the desired sound signature... all without swapping modules. For some it's easier to swap a B1 module in instead of output source and that's a perfect solution as well.
 
 
 

The correct way to get the desired sound you like is to change out the modules which is what the modules were designed for.

 

[AtlanticProSnd]

  There's resistance and there's impedance. Two different terms. Resistance is just added by resistors. Impedance can be added by resistances, capacitances and inductances. I tested UEBJ against a 20ohm resistive impedance adapter and UEBJ is not purely resistive.
 
 
 
If you have not heard the 64 Audio U12 with and without an impedance adapter and commenting on its performance purely on a speculative basis, I would suggest you cease to do so immediately as it's against the forum rules to subjectively comment on sound quality without at least trying the aforementioned product. 

Who ever said I have not heard the A12's with a impedance adapter?  Not only have I tried them I made a custom one with variable impedance.  Talk about De-tuning.

 

[seamon]

Who ever said I have not heard the A12's with a impedance adapter?  Not only have I tried them I made a custom one with variable impedance.  Talk about De-tuning.:eek:

Did you hear a frequency change? Specifically, an increase in Treble and decrease in bass?

 

[AtlanticProSnd]

Did you hear a frequency change? Specifically, an increase in Treble and decrease in bass?

For sure!  Less bass and phase issues.  Was not a positive experience.  These impedance matching devices are designed to help when listening to airline fairly high impedance output. Not to shape the sound signature. 

 

[seamon]

 
For sure!  Less bass and phase issues.  Was not a positive experience.  These impedance matching devices are designed to help when listening to airline fairly high impedance output. Not to shape the sound signature. 

Understandable. Most of us appreciated this change because for us it was a positive change from the otherwise dark sounding U12/A12 and that's why we recommend them. If you don't like the sound with an adapter then so be it.

 

[subguy812]

  Understandable. Most of us appreciated this change because for us it was a positive change from the otherwise dark sounding U12/A12 and that's why we recommend them. If you don't like the sound with an adapter then so be it.

I have not ventured down the road with adapters. I have found a great DAP and use a OCC Silver Litz cable, it is possible the cable provides impedance, I don't know.

 

[PinkyPowers]

I have not ventured down the road with adapters. I have found a great DAP and use a OCC Silver Litz cable, it is possible the cable provides impedance, I don't know.

Silver has less resistance than any other material. And I can confirm, it does lighten the sound of my U12.

 

[seamon]

In my experience, a silver litz wire tightens up the bass, improves impact a tad and eliminates any sort of sibilance. 

 

[bavinck]

OK, guys/gals, here is a thought.  There are theories, measurements, calculations, and everything else that makes sense on paper.  And then, there are first hand, or as I call it "first ear" experience of what people hear and how they perceive the sound based on a synergy with their sources, the eartips selection, the cable they switched too, their ear/earcanal anatomy, and other factors unique to every individual case.

Who to say they are right or wrong?   The end result is a satisfaction we get when that soundwave reaches our brain and puts a smile on our face.  If someone hears it sounds better (or worse) to them with an impedance adapter of certain value, let it be. Either way, if it sounds good to you and you are happy, no need to argue or to prove each other wrong.

Good thought. However, at least one person in this argument is obviously not trained in physics and is spreading incorrect information.

 

[bavinck]

The USBPre2 is not designed for low impedance devices (Bad comparison)  Should have used Pro gear for this as that is what his claim is.  USBPre2 is a preamp not a amp and not designed for low impedance loads.  It's designed to drive an amp.  It does have a Phones out for non-critical monitoring however the design of this device is to drive an amp or mixing console input.
Not true at all.  I have worked in pro audio for 30 years and have NEVER seen any pro gear that has an output impedance higher then 2.5 Ohms (most are measured less then 1 ohm).

The correct way to get the desired sound you like is to change out the modules which is what the modules were designed for.

Just let it go. You are responding to posts that are months old. This argument has already happened with 64,way before your time. You are NOT adding anything new to the conversation.

 

[AtlanticProSnd]

  In my experience, a silver litz wire tightens up the bass, improves impact a tad and eliminates any sort of sibilance. 

I agree 100%  For me going balanced made yet another big improvement.

 

[AtlanticProSnd]

Just let it go. You are responding to posts that are months old. This argument has already happened with 64,way before your time. You are NOT adding anything new to the conversation.

I was responding to a post that was done today.  Nothing to let go.  Just stating facts.

 

[AtlanticProSnd]

  Understandable. Most of us appreciated this change because for us it was a positive change from the otherwise dark sounding U12/A12 and that's why we recommend them. If you don't like the sound with an adapter then so be it.

Different strokes for different folks.  If you like the sound your getting that's all that matters.

 

[bavinck]

I was responding to a post that was done today.  Nothing to let go.  Just stating facts.

The quote in that post was months old. Not sure 64 even reads this thread anymore. Since their divorce with Adel I think they stay in their own thread now.

 

[AtlanticProSnd]

  @Brooko has some graphs in his review in which he has compared the 64 Audio U series IEMs with and without an impedance adapter. It indeed shows a frequency response change.

It does in fact change the frequency curve as I stated in my first post, however technically the correct way to achieve this is to change the venting and or change the actual filters inside the IEM.
If you are happy adding stuff to the signal chain to get the sound your after it doesn't really matter.