Do the DT770 Pro commonly have poorly matched drivers?

Quote:

Originally Posted by pro1137 

Hello Head-Fi'ers. I was wondering if the DT770 Pro are known for having poorly matched drivers. I feel like there's a pan to the left of my pair and I wanted to know if I should get a replacement pair (they are new; free returns). Should I? Or is this a common issue with the DT770 Pro?

There is no common issue with any of the Beyers DT line or T line.

RMA yours if you think something is wrong. Try from different sources, check your connections, play different media back, before doing this to confirm it's the headphone and not something you or your media hardware is doing.

Very best,

Quote:

Originally Posted by pro1137 

Hello Head-Fi'ers. I was wondering if the DT770 Pro are known for having poorly matched drivers. I feel like there's a pan to the left of my pair and I wanted to know if I should get a replacement pair (they are new; free returns). Should I? Or is this a common issue with the DT770 Pro?

I own 7 Beyerdynamic headphones, no miss matched drivers, as far as I can tell.

I just received my DT 770 Pro 80 ohms from ebay today and the left ear volume sounds much lower than the right ear for some reason.

I went through three (3) DT770 600 Ohm (Premium) from different sources and they all had severely mismatched drivers. Finally Beyerdynamic (yes, I was contacted by HQ) sent me cherry picked pair that was okay, they also threw in some freebies like T-shirt, some demo CDs for my troubles.

If you have multimeter you can easily measure the impedance difference between left and right driver.

1. Sleeve: usually ground
2. Ring: Right-hand channel for stereo signals, negative polarity for balanced mono signals, power supply for power-using mono signal sources
3. Tip: Left-hand channel for stereo signals, positive polarity for balanced mono signals, signal line for unbalanced mono signals
4. Insulating rings

Never had any issue with my own DT770s for almost 2 years now. There was a website with test files for these sort of things but it's name slips my mind..
 

The impedance difference will not show the actual acoustic difference, though, which can have other reasons than a simple impedance mismatch between the drivers. An imbalance of 3 dB (roughly the threshold where it becomes clear and annoying) is equivalent to about 1.4 times higher voltage on one channel, or twice as much power. However, chances are that the impedance would not differ by more than a few percents, which by itself is not much of a problem.

Quote:

Originally Posted by stv014 

 

The impedance difference will not show the actual acoustic difference, though, which can have other reasons than a simple impedance mismatch between the drivers. An imbalance of 3 dB (roughly the threshold where it becomes clear and annoying) is equivalent to about 1.4 times higher voltage on one channel, or twice as much power. However, chances are that the impedance would not differ by more than a few percents, which by itself is not much of a problem.

You could be right, my experience and common wisdom here are that impedance mismatch is the number one reason for channel imbalance. And Beyerdynamic is notorious for mismatching drivers.

Quote:

Originally Posted by Andrew_WOT 

 

You could be right, my experience and common wisdom here are that impedance mismatch is the number one reason for channel imbalance.

Does anyone have headphones with one channel having 1.5 times higher impedance than the other (excluding the case of faulty drivers) ? As I already explained, a few percents of impedance mismatch is not enough by itself for an audible imbalance. Of course, a severely imbalanced pair could very well have some driver impedance mismatch as well by coincidence, but so have others without an audible balance problem.

Quote:

Originally Posted by stv014 

 

The impedance difference will not show the actual acoustic difference, though, which can have other reasons than a simple impedance mismatch between the drivers. An imbalance of 3 dB (roughly the threshold where it becomes clear and annoying) is equivalent to about 1.4 times higher voltage on one channel, or twice as much power. However, chances are that the impedance would not differ by more than a few percents, which by itself is not much of a problem.

I am really not sure how did you come up with all these numbers, are these Beyer QC standards? 0.5 db difference is already quite audible, at which level it becomes "annoying" is very subjective. All brands I have and had in my stack were pretty accurate for R/L impedance match. Beyer was the only one way over chart except Manufaktur pair.

Proper Left/Right balance is essential for building field depth and providing proper positioning, reason DACTs are so popular among headamp builders, so imbalance does not have to be that severe or "annoying" to have an impact on SQ.