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Balanced TRS vs 3.5mm stereo cable, Are they the same?
bennetng
post Apr 16 2013, 19:13
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[1] If I plug two 3.5mm to 6.3mm stereo adapters into a stereo miniplug cable, can I use it as a balanced TRS cable?
[2] If I plug two 6.3mm to 3.5mm stereo adapters into a balanced TRS cable, can I use it as a stereo miniplug cable?

I ask this because I did [1] on my office's RME Multiface II audio interface and ran RMAA, but I only got about -102dB noise. According to my google search such as "rme multiface rightmark" and RME's official spec, similar models usually score lower than -110dB. I checked my RME mixer's setting, tweaked the +4/-10 switch but still cannot achieve better result.

I used a $2 RCA cable to test my Creative X-Fi Titanium HD soundcard and got -119dB so I don't think I need to spend a lot on cables in order to make a proper test. I also don't want to spend money to buy two balanced TRS cables (which are useless to me at home) to test the RME.

Just wondering are [1] and [2] basically the same thing?

Thanks!

This post has been edited by bennetng: Apr 16 2013, 19:14
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greynol
post Apr 16 2013, 19:17
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Did you check to see if stereo crosstalk was made worse by using a balanced TRS cable instead of a separate coaxial cable for each channel?


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bennetng
post Apr 16 2013, 19:21
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Thanks for moving the post to the correct forum.
The fact is I only used one stereo cable to check the RME's left channel and turned mono mode on RMAA, therefore I did not check the stereo crosstalk.

This post has been edited by bennetng: Apr 16 2013, 19:25
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bennetng
post Apr 18 2013, 18:56
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I guess I know the reason now. There are a lot of background services running in the office PC including Novell Netware, Symantec Endpoint Protection, some Intel RAID related stuffs and many other unknown stuffs. Maybe they are the culprits. I am not 100% sure because I do not have right to turn them off but I did a simulation on my home PC, running RMAA while running both CPU and GPU benchmarks and I only got -114dB noise.

The office PC is a Dell with i5 2320 and my home PC is a self-built i3 540. Ironically my home PC is more responsive (time needed to open a Window for example).

This post has been edited by bennetng: Apr 18 2013, 18:59
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MikeFord
post Apr 19 2013, 04:00
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Aren't you kind of close the noise floor of the test arrangement to take a few db of difference as other than test error?
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bennetng
post Apr 19 2013, 06:09
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QUOTE (MikeFord @ Apr 19 2013, 11:00) *
Aren't you kind of close the noise floor of the test arrangement to take a few db of difference as other than test error?


I did the test 4 times to average out the errors, the busy results are obviously more noisy.
http://www.hydrogenaudio.org/forums/index....ost&id=7501
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MikeFord
post Apr 20 2013, 10:24
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QUOTE (bennetng @ Apr 18 2013, 22:09) *
QUOTE (MikeFord @ Apr 19 2013, 11:00) *
Aren't you kind of close the noise floor of the test arrangement to take a few db of difference as other than test error?


I did the test 4 times to average out the errors, the busy results are obviously more noisy.
http://www.hydrogenaudio.org/forums/index....ost&id=7501

I'm not a fan of black box assume it works properly testing, I like to know all the details of how the tests are performed, what are the areas of sensitivity where results might be more questionable etc.

In this case it seems a bit odd that the major difference is in crosstalk below 100hz, and as far as I can tell no other area. Without knowing more I would not have much confidence in linking cause and effect.
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andy o
post Apr 22 2013, 08:09
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QUOTE (bennetng @ Apr 18 2013, 10:56) *
The office PC is a Dell with i5 2320 and my home PC is a self-built i3 540. Ironically my home PC is more responsive (time needed to open a Window for example).

Opening a window would not be CPU-bottlenecked. Probably hard drive. My laptop went from opening iTunes in a bit less than 20 seconds to about 5 when I installed an SSD a few years ago. SSDs are actually fast enough that my Core 2 Duo actually is the bottleneck during the Windows startup apparently.
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bennetng
post Apr 23 2013, 06:55
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Solved. Need to select 32-bit int instead of 24-bit to make a real 24-bit recording. 24-bit is basically same as 16-bit but slightly lower noise (-96 vs -102) just because RMAA's 16-bit test signal is dithered. 32-bit int scored -111dB and 32-bit float has no signal at all.

Well done RME, interesting drivers.
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