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I just bought Samson Resolv SE5 speakers for my home pc/amature home studio. I have very annoying hissing sound and scratches whenever they are plugged into the pc. My sound card is ESI Maya44 XTE, which has unbalanced stereo output large jack.

I tried connecting with a Y cable, one stereo to two monos (left/right). but the speakers make the hissing sound and some scratches.

I tried with from stereo jack to RCA to the speakers, again unbalanced and the noise persists. The same setup when connected to another device like my cellphone works without noise which makes me think its some grounding issue or something, and proves that the new speakers are not broken. To add up to that, the noise does not appear when the pc is booting, but appears when it is idle or just browsing , playing music etc.

What I have not tried is Y cable, stereo to two stereo jacks, which according to the speakers manual is for balanced signals. But I am not sure its a good idea since the card says explicitly that the output is unbalanced.

links with the manuals

Samson Resolv SE5

ESI MAYA44 XTE

Any thoughts are really appreciated.

Kind Regards

EDIT: problem does NOT appear by using stereo small jack from a laptop, to RCA at the speakers. And there can be no lousier output than from a cheep onboard from a laptop.

closed as off-topic by Matthew Read Mar 23 '16 at 18:32

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    You don't have a balanced output on that sound card, so you can't make a balanced connection (balanced connections require balanced outputs, balanced cables, and balanced inputs). I think you've already determined the problem is the sound card. You could look into a USB audio interface, most of which have higher quality output electronics, including balanced outs. – Todd Wilcox Mar 23 '16 at 11:58
  • thanks for your answer, could it be grounding problems, like a ground loop ? the speakers and the pc are in different plugs – thahgr Mar 23 '16 at 11:59
  • It's most likely cheap output electronics on the sound card itself. It could be ground noise but you'll probably never be able to get rid of it on a device with unbalanced outs. – Todd Wilcox Mar 23 '16 at 12:01
  • ok bad news for me, but when I had my cheap logitech 2.1 speakers, there was no problem. I will try with the onboard of the pc later today to specify the problem more. – thahgr Mar 23 '16 at 12:03
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    I'm voting to close this question as off-topic because it is not about music. I'm not sure if this would be on-topic at Sound Design. – Matthew Read Mar 23 '16 at 18:32
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The linked manuals show the speakers are 10 kOhm input impedance, while the analog output from your sound card is 33 Ohm output impedance.

I can pretty much guarantee that that'll never work. Your sound card expects to be driving cheap headphones; you need a high-impedance "line out" signal for those speakers.

  • ok, this totally make sense, my mistake that I missed it.. Do you have any suggestions on alternatives ? could you help me with some options ? – thahgr Mar 23 '16 at 13:46
  • wait, but then how can it work from my cell phone with a small stereo jack to RCA with no problems ? – thahgr Mar 23 '16 at 13:47
  • problem does NOT appear by using stereo small jack from a laptop, to RCA at the speakers. And there can be no lousier output than from a cheep onboard from a laptop. The problem is somewhere else, that is why I unselected it from "accepted answer" – thahgr Mar 23 '16 at 16:45
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  • Carl, I think you've got the wrong idea on how these two impedances are supposed to work. These are bridging impedances. As the article states, this maximizes voltage transfer while minimizing current draw. The actual problem is almost certainly poor-quality, noisy DAC and output electronics. – Todd Wilcox Mar 23 '16 at 18:02
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I think the problem is that the expected input for the 1/4 inch line-level is expected to be +4dBu.

The manual for the sound card uses different units, but quotes +6dBV (a capital V) @ 0 dbfs (pages 18-19). I think this means that at maximum sound level in the digital domain, the output is going to be +6dBV and I think this loosely translates to about +13dBu to +18dBu.

If you tried adjusting the output faders (not the "knobs") in your soundcard driver applet (page 13) to something like -9dB to -14dB when using the 1/4" line-in on the monitors, you might eliminate the noise.

See, for example, ( https://support.biamp.com/General/Audio/Gain_structure%3A_input_and_output_levels )

As to why the RCA works OK, I don't know, but the device clearly has different expectations ({magic}) from different inputs.

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