I'm purchasing a set of headphones that runs the headphone cable only to one side of the headphone (i.e. they don't split visibly to two different wires outside the headphone cup).
Inside the first cup there are a connection spots for the left and right cup signal wires respectively AND a shared common ground which then leads to both cups.
The standard cable that comes with the headphone is therefor a three wire cable with a shared ground along the whole of the signal path after the headphone amp.
Now, I'm concerned about crosstalk due to the shared ground and especially the low impedance (40 Ohms) of the phones.
I've seen measurements (for Sony MDR V6) that shows that the crosstalk noise components can rise up to the relative level of -30 dB compared to the signal level.
This is clearly not acceptable for my purposes.
Is there any way I can hack/modify such headphones (by building my own cables) in order to reduce this type of crosstalk?
I'm sure I could get rid of it with proper cable construction and IF I could have separate ground contacts for each transducer. However, I don't think I'm brave enough to tear apart my $300 USD headphones band in order to fit a separate ground wire for the second cup.
So, can anything be done (to crosstalk) just by exchanging the cable, if the contact at the end of the headphone has only one place for the ground to which both transducers are connected?
All help / corrections are welcome.
Best regards,
Halcyon
PS I'm an electronics novice, but you don't have to treat me with silky gloves. If I can't understand the explanation with my own books (and net searches) I'll ask for a clarification.
Inside the first cup there are a connection spots for the left and right cup signal wires respectively AND a shared common ground which then leads to both cups.
The standard cable that comes with the headphone is therefor a three wire cable with a shared ground along the whole of the signal path after the headphone amp.
Now, I'm concerned about crosstalk due to the shared ground and especially the low impedance (40 Ohms) of the phones.
I've seen measurements (for Sony MDR V6) that shows that the crosstalk noise components can rise up to the relative level of -30 dB compared to the signal level.
This is clearly not acceptable for my purposes.
Is there any way I can hack/modify such headphones (by building my own cables) in order to reduce this type of crosstalk?
I'm sure I could get rid of it with proper cable construction and IF I could have separate ground contacts for each transducer. However, I don't think I'm brave enough to tear apart my $300 USD headphones band in order to fit a separate ground wire for the second cup.
So, can anything be done (to crosstalk) just by exchanging the cable, if the contact at the end of the headphone has only one place for the ground to which both transducers are connected?
All help / corrections are welcome.
Best regards,
Halcyon
PS I'm an electronics novice, but you don't have to treat me with silky gloves. If I can't understand the explanation with my own books (and net searches) I'll ask for a clarification.
No, I'm not kidding.
I have seen actual measurement data of headphones which have a shared common ground and with which the crosstalk components exist at the relative level of -30 dB below signal.
These tests were conducted by expert psychoacousticians and audiometric personnel who specialize in the audibility tests.
Their recommendations NOT to buy any headphones with a shared ground (unless you have a way of measuring it's crosstalk components) sure looks valid to me.
Most high quality audiophile and studio headphones have a separate ground wire for each cup.
Not all, but many of them.
Honestly, what make you think that I am kidding?
Have you not heard about cable crosstalk (induced by shared ground) before?
regards,
Halcyon
I have seen actual measurement data of headphones which have a shared common ground and with which the crosstalk components exist at the relative level of -30 dB below signal.
These tests were conducted by expert psychoacousticians and audiometric personnel who specialize in the audibility tests.
Their recommendations NOT to buy any headphones with a shared ground (unless you have a way of measuring it's crosstalk components) sure looks valid to me.
Most high quality audiophile and studio headphones have a separate ground wire for each cup.
Not all, but many of them.
Honestly, what make you think that I am kidding?
Have you not heard about cable crosstalk (induced by shared ground) before?
regards,
Halcyon
Some headphones have shared ground and this can result in a little bit crosstalk. When the cable is separated into two wires all the way from the connecter to speaker elements, you will get better separation. My (quite good) Sennheiser HD545 reference (in fact most Sennheiser phones) has separate cables all the way.
I think though that your concern is a little bit "overkill". In order to get good stereo you need 10-15 dB channel separation. Compare to the good old vinyl with approx. 20 dB channel separation.
Have you tried the headphone experts at www.headwize.com ? try also www.head-fi.com
I think though that your concern is a little bit "overkill". In order to get good stereo you need 10-15 dB channel separation. Compare to the good old vinyl with approx. 20 dB channel separation.
Have you tried the headphone experts at www.headwize.com ? try also www.head-fi.com
peranders,
I'm trying to locate a suitable closed circumaural headphone pair for psychoacoustic testing. Hence I have a higher requirements for crosstalk immunity than with normal listening (if not for anything else, but so that nitpickers can't shoot down the test setup based on that).
Thanks for the tip on head-fi and headwize. I have discussed the problem in Head-Fi forums (but not yet at headwize). I have done extensive searches on the issue on the net and read the relevant parts in 'Loudspeaker and Headphone Handbook' (2001 ed.)
The trouble is finding people who have actually constructed their own replacement cables and actually measured their crosstalk when connected to an actual pair of headphones with a shared ground connector.
Currently I don't have the needed measuring equipment (nor enough trust in my skills) to test myself, which makes life a little bit more difficult
But back to my original question:
Can something be done to alleviated the normal three cable wire and a shared common ground contact in otherwise high quality pair of headphones?
I'm trying to locate a suitable closed circumaural headphone pair for psychoacoustic testing. Hence I have a higher requirements for crosstalk immunity than with normal listening (if not for anything else, but so that nitpickers can't shoot down the test setup based on that).
Thanks for the tip on head-fi and headwize. I have discussed the problem in Head-Fi forums (but not yet at headwize). I have done extensive searches on the issue on the net and read the relevant parts in 'Loudspeaker and Headphone Handbook' (2001 ed.)
The trouble is finding people who have actually constructed their own replacement cables and actually measured their crosstalk when connected to an actual pair of headphones with a shared ground connector.
Currently I don't have the needed measuring equipment (nor enough trust in my skills) to test myself, which makes life a little bit more difficult
But back to my original question:
Can something be done to alleviated the normal three cable wire and a shared common ground contact in otherwise high quality pair of headphones?
halcyon said:
Yes! Use headphones with separate cables like Sennheiser or change cables at your headphones.
I had long time ago a 3 x 0.4 mm sqr to my speakers. The cable was 10 meters. The resistance of the common ground cable was not small, 1.4 ohms in each wire and 4 ohm speakers.....not audiophilic connection..
Don't forget that you have crosstalk in your head also!
Also 3.5 mm stereo-plug uses Common GND
Also the very much used 3.5mm stereo plugs use common GROUND.
And the headphones use that or 6.3mm stereo "teleplug".
I do not like it.
I want to be able to put the common ground at the place where I think it is best.
The RCA phono plugs use separate,
which makes it easy to use separate cables.
These cables could be joined by some sort of clips, or those things
used to hold together cables inside electronics.
Or some tape.
Also the very much used 3.5mm stereo plugs use common GROUND.
And the headphones use that or 6.3mm stereo "teleplug".
I do not like it.
I want to be able to put the common ground at the place where I think it is best.
The RCA phono plugs use separate,
which makes it easy to use separate cables.
These cables could be joined by some sort of clips, or those things
used to hold together cables inside electronics.
Or some tape.
peranders said:
I had long time ago a 3 x 0.4 mm sqr to my speakers. The cable was 10 meters. The resistance of the common ground cable was not small, 1.4 ohms in each wire and 4 ohm speakers.....not audiophilic connection..
.... I ment 0.4 square millimeters = 0.437 ohms! Still it was noticable.
headphone crosstalk
The phones shouldn't crosstalk. Make the measurement through the amplifier. The low source impedence should keep the crosstalk down. If you are making the measurement with one side disconnected, put a 4.7 ohm resistor across the side under test to simulate a real world condition
The phones shouldn't crosstalk. Make the measurement through the amplifier. The low source impedence should keep the crosstalk down. If you are making the measurement with one side disconnected, put a 4.7 ohm resistor across the side under test to simulate a real world condition
There are people who are supposedly "in the know" that will say many things.
I saw an advertisement proclaiming that a 200 dollar power cord could improve high frequency definition. Never mind the fact that it is plugged into a 99 cent residential grade duplex outlet and feeding from an electrical distribution pannel with 5 dollar circuit breakers.
I see many haedphones in my line of work. Sharing a common ground is commomplace. My headphones are not the best either. I use KOSS POR-4 ear crushers. I listen to a lot of mid 1960's stereo. There is defineatly separation there!
I saw an advertisement proclaiming that a 200 dollar power cord could improve high frequency definition. Never mind the fact that it is plugged into a 99 cent residential grade duplex outlet and feeding from an electrical distribution pannel with 5 dollar circuit breakers.
I see many haedphones in my line of work. Sharing a common ground is commomplace. My headphones are not the best either. I use KOSS POR-4 ear crushers. I listen to a lot of mid 1960's stereo. There is defineatly separation there!
Crosstalk?
The flexible cables used for headphones will have significant resistance, so a common ground will cause some crosstalk. For music, most people would say this was advantageous because it reduces the "hole in the head" phenomenon. If, however, you are attempting to test people's hearing, you need to avoid this crosstalk.
It's easy enough to calculate roughly what the crosstalk due to a common conductor will be. Measure the resistance of the ground cable with a good DVM or component bridge, do the same for one transducer, and you have a potential divider. Convert the loss into dBs, and that's your crosstalk.
Probably the easiest way of solving the problem is to buy some cheap Sennheisers with their individual cables, remove the cables, and wire them into your expensive headphones.
The flexible cables used for headphones will have significant resistance, so a common ground will cause some crosstalk. For music, most people would say this was advantageous because it reduces the "hole in the head" phenomenon. If, however, you are attempting to test people's hearing, you need to avoid this crosstalk.
It's easy enough to calculate roughly what the crosstalk due to a common conductor will be. Measure the resistance of the ground cable with a good DVM or component bridge, do the same for one transducer, and you have a potential divider. Convert the loss into dBs, and that's your crosstalk.
Probably the easiest way of solving the problem is to buy some cheap Sennheisers with their individual cables, remove the cables, and wire them into your expensive headphones.
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