How much crosstalk does it take before the stereo imaging effect brakes down? Out of curiosity, how much exists in the vinyl world?

I recently got an outboard Dac, and for mono and early stereo(i.e. hard panned) recordings, it blows my iPod out of the water. But real stereo recordings just sound bad on it...the mix collapses, and the sound comes directly from the speakers, instead of from in between them like with my iPod.

iPod 4G/Dac-AH => Sonic Impact T-amp => Athena AS-B1

I just set this up in my dorm room, and was blown away with the iPod, but underwhelmed with the Dac. In fact, I'd much rather listen on the iPod, even though I can now notice slight distortion in it. Double blind tests are hard when you're switching cables around from sources with different, non-adjustable levels, but a few of my friends commented on it. And things like high frequency EQ can affect imaging, too, so I didn't know where to start.

I measured a few different sets of cables with a multimeter(looked good, no obvious shorts). Then I played a tone through one channel, and measured the voltage on each. I got the following values for stereo crosstalk:

-53dB @ 10Hz
-53dB @ 100Hz
-59dB @ 1kHz
-59dB @ 10kHz

My iPod comes in at -104dB(found online), woah, that's many orders of magnitude different!

The opposite channel was toward the low range of the multimeter(it read 0.001 or 0.002 volts), but these numbers match around what was audible(at 1KHz, I didn't repeat all the tests by ear).

Since I don't trust my multimeter at the absolute low end of its scale, I did a couple quick measurements with my ears and a SPL meter. The room was noisy (maybe ~40dB ambient...this is a dorm room with a computer running), so these are very rough estimates. I unplugged the left channel of the dac from the amp(thus the crosstalk of the amp was not a variable), and generated tones on the left channel. I then turned the volume of the amp up until I could hear the tone from the unconnected channel. I then played the tone on the right channel, and measured the level with the SPL meter. So between the Fletcher-Munson curves(of my ears), my hearing ability, the ambient noise, and my speaker's response, these figures are probably optimisitic by ~30-45dB. I just did this to verify that my multimeter wasn't crazy at it's low end.

Level @ Could perceive tone on opposite channel in noisy room
N/A @ 10Hz
-95dB @ 100Hz
-84dB @ 1kHz
-82dB @ 10kHz

Add that 30-45dB of optimism back, and my multimeter measurements were in the ballpark. I wish I had a good soundcard to run an RMAA test with, but my Audigy has pretty bad crosstalk on its own.

You can actually get away with quite a lot of crosstalk before the stereo illusion is destroyed. Vinyl can give pretty good imaging, and typical channel separation figures for a good vinyl setup would be about 25-30dB at 1kHz, and much less at higher frequencies (eg. 15dB at 10kHz).


It could simply be that your speakers are too far apart relative to the listening position.

The fact that your iPod doesn't exhibit the same characteristics (I presume played back over the same speakers) is evidence that it has rather poorer channel separation than the DAC. Is it possible that the iPod has a deliberate partial mixing of the channels to compensate for the fact that most listening will be via headphones (where some reduction in the image width can be beneficial)? Anyone around here know about this?


I simply don't believe that figure for the iPod. It's ludicrously high. Sounds like something a marketing man invented while lying in the bath one day.

Okay, I ran the Dac through RMAA with my Audigy...not knowing if the Audigy would see anything. It did:

Dac: -66dB
iPod: -85dB(measured value found online elsewhere from more reputible source)


So the iPod has *more* separation than the Dac! I tried adding crossfeed to the dac(under the assumption that the iPod may have had less separation...to try to simulate it), but it didn't help. I tried moving forward and backwards from the speakers(it's hard to move them closer), but it didn't help.

-66dB is very very high for a Dac...I wonder if something's wrong with it. If the channels are leaking, I'm not sure of their relative phase, which could be causing the issues.

Maybe it's your analog cables that are broken.