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geekhack Community => Other Geeky Stuff => Topic started by: shortround on Sat, 19 December 2015, 13:09:18
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Hi Geekhakers, I am the happy new owner of a pair of JBL LSR305 speakers. I am not a music producer, nor do I work in audio professionally. I simply wanted some nice accurate transparent speakers to enjoy music with. With my computer, I use the little schiit-stack dac & amp for my headphone needs, but with my speakers I still use the most basic direct to computer connection, (a 3.5mm to XLR y cable). I'm pretty happy with the sound card of my computer (it's a 2012 imac, for whatever that's worth), and my speakers sound fantastic when I'm using them, but when I'm not playing any audio, they have that unwanted hiss. Even at 4/10 volume setting I'm hearing it. I don't currently have the money to spend on a balanced dac, but I might try to save up for one if that could eliminate the hiss. Even if the computer is turned off and the speakers turned on, the hiss is there, so I'm wondering if it could be my power source? It's definitely not the dreaded hum, but a hiss.
Any thoughts?
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I'm no expert, but it sounds like you already have a DAC in the stack. If possible, I would plug the speakers into that to see if the hiss goes away. If it does, then you have an answer. It would be better to actually find the source of the problem before trying to fix it. I wouldn't be surprised to see the hiss isolated to that 3.5 jack.
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By "dreaded hum" do you mean it's not a ground loop? That's often the bane of computer audio. Sounds strange but bite the 3.5mm and see if the noise goes away - you're a good ground :))
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You might check "source" or "input" to see if "What You Hear" is ticked - that can bring in weird stuff sometimes.
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Is the hiss based on the volume level of the speakers? Have you tried turning down the speakers and turning up the "output volume" on the computer? Is the hiss still there if you unplug the cables from the speakers?
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Is the hiss based on the volume level of the speakers? Have you tried turning down the speakers and turning up the "output volume" on the computer? Is the hiss still there if you unplug the cables from the speakers?
Yes, I've been trying to find the best balance between volume and hiss, right now I'm keeping the speaker volume around 4 of 10 and adjusting the computer volume accordingly. The hiss does get louder if I raise the speaker volume up. EDIT: The hiss is still there after unplugging the XLR cables.
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I'm no expert, but it sounds like you already have a DAC in the stack. If possible, I would plug the speakers into that to see if the hiss goes away. If it does, then you have an answer. It would be better to actually find the source of the problem before trying to fix it. I wouldn't be surprised to see the hiss isolated to that 3.5 jack.
This sounds like a really good idea, my dac uses unbalanced rca jacks though. I'm still going to try it to see if it helps... as another user said, maybe it is that 3.5mm jack, so this could at least rule that out. I think I might have an RCA to TRS cable lying around so I'll try this.
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Definitely worth trying. You should gain the added advantage of being able to plug in the headphones to automatically direct sound to headphones, and unplugging them to get pass-though to speakers.
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Definitely worth trying. You should gain the added advantage of being able to plug in the headphones to automatically direct sound to headphones, and unplugging them to get pass-though to speakers.
My Schiit Modi DAC has only one rca out jack, so it's a choice between going to the Magni headphone amp, or to the speakers, unless I maybe get piggy back cables. So it's not a dac/amp combo.
At any rate, I connected my Modi amp to the speakers to see what happened, and the hiss is still there. This at least rules out the little 3.5mm jack on the computer.
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Modi to Magni, and then Magni pre-outs (L / R) to Speakers would be the solution to that, but yeah, you'd need the cabling.
Based on your test though, sounds like it isn't related to the Soundcard's DAC.
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These things seem to use the generic "pc" type power cables, so I might try changing those out next.
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I've always learned that mini jack 3.5 causes humming because of the fact that L/R rings are so close to each other which may cause crossover.
I have ES-5's with a Focusrite 2x2. I don't know if it is too much for your wallet, but I found it relatively cheap: XLR to to large jack, separate L/R channels.
I experienced the same you do, tried switching power cords, different outlet in the wall or in the house. Etc. Switched to Focusrite and went XLR-Large jack and it was over immediately.
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I've always learned that mini jack 3.5 causes humming because of the fact that L/R rings are so close to each other which may cause crossover.
Balanced cables like XLR have common mode rejection - basically it takes a single signal, makes an inverted copy, and sends both down a pair of cables. The pair picks up noise, but when the signals arrive at their destination, they're subtracted from each other. Since one is inverted, you end up with the original signal back, less the noise it picked up on the way.
Unbalanced cables (such as TRS, in whatever size) don't reject common mode noise and will pick up some. Better shielding can mitigate it somewhat but it's always there to some extent.
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I've always learned that mini jack 3.5 causes humming because of the fact that L/R rings are so close to each other which may cause crossover.
Balanced cables like XLR have common mode rejection - basically it takes a single signal, makes an inverted copy, and sends both down a pair of cables. The pair picks up noise, but when the signals arrive at their destination, they're subtracted from each other. Since one is inverted, you end up with the original signal back, less the noise it picked up on the way.
Unbalanced cables (such as TRS, in whatever size) don't reject common mode noise and will pick up some. Better shielding can mitigate it somewhat but it's always there to some extent.
Cool to know, didn't knew that! I do have some occasional white noise sometimes however.. But I mostly don't hear it, only when it is really really quiet like in the really late evening or so.