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Remove hiss?

Discussion in 'Sound Science' started by PDVJAM, Jul 10, 2019.
    Hey! I've just bought new and sensitive iems (CA Solaris) and now I hear very noticeable hiss from my portable iBasso DX80 player. Is there any way to eliminate that hiss or the only way is to change DAP for a more "silent" one?
  2. bigshot
    I'm not familiar with those specific components, but it sounds like you might need a headphone amp. Have you checked to see what the recommended impedance/sensitivity rating is for your player? The problem isn't the DAP. It's the IEMs you are using. They probably need an amp to work well with that player.
    Last edited: Jul 10, 2019
    Well, I don't know what the recommended values, but you can check DAP specs here.
    IEM specs are: 115 dB SPL/mW Sensitivity and 10 Ohms@1kHz Impedance.

    I've just tried several more DAPs, like iBasso DX220, iBasso DX150, FiiO X5 III - they all have noticeable hiss with this IEMs. Didin't checked with separate AMPs though.
  4. bigshot
    IEMs are known for needing amping with portable players. Someone with more knowledge of the math involved will probably chime in soon. This isn’t a subject in my wheelhouse.
    PDVJAM likes this.
  5. castleofargh Contributor
    the real fix is to have a source with incredibly low background noise, or to avoid overly sensitive IEMs. nobody is ever happy about such an alternative.
    for a DAP, you can replace it or add an amplifier that's known to have low background noise and handle low impedance IEMs fine(which is NOT what most portable amps are designed for!). another option is to add one of those fancy voltage divider cables(ifi audio sells some of those. Earbuddy or some name like that), you basically attenuate everything, music and noise, then hopefully when you increase the volume of the DAP to compensate for that wasted power, the background noise remains low. it works very well most of the time, but there are 2 things to consider:
    1/ you need to have ample voltage headroom in your DAP to compensate for the attenuation and still reach the loudness you want.
    2/ the extra circuit will affect the impedance "perceived" by the amp, and also by the IEM. that could result in audible change in signature, and in case of a low impedance IEM, it could also end up limiting the current(which could be a good thing for some DAPs, and a bad thing for the IEM, depending on the gears). but in any case it's not an ideal situation, consider that to be a band-aid until you decide who to sacrifice, the DAP, the IEM, or maybe both once like me, you're become a fully fledged hiss parano.
  6. bigshot
    Are there amps designed for this particular problem? What portable source would have a sufficiently low noise floor? I would guess that an attenuating cable would result in too low a volume level with a portable DAP.

    Every time I hear about a situation like this, I wonder why they make stuff that doesn't work properly with the sort of thing most people would plug them into. It makes no sense to me. It's like they're deliberately making people jump through hoops.

    Edit: There appear to be some people who know what they are talking about in this thread... OP might check here. https://www.head-fi.org/threads/best-amp-for-high-sensitivity-iems-none.465475/
    Last edited: Jul 10, 2019
    PDVJAM likes this.
  7. castleofargh Contributor
    the trend in IEM is(I'm simplifying a lot)to stack drivers so they can reach the same SPL while keeping distortions low. that turns out to be a real problem for DAPs, but unless the DAP bleeds out current and distorts like mad, usually the overall result is still that they have improved on the transducer side that was the weak link in fidelity.
    as to absurd sensitivity turning small background noise into very audible hiss. well that can be one of the consequences. but in my experience, it's pretty tricky to properly estimate what's going to happen. DAP specs will probably give SNR values unloaded or into a non problematic load, and IEMs will give sensi for only 1kHz. so some IEMs will show 120 or 125dB at 1mw and not feel as hissy because they don't torture the DAP or because they have a recessed upper mid range(or both).

    I personally don't like any of it. I've stopped purchasing stuff that go below 16ohm or have a sensi that seems really high. and I always look for people mentioning hiss for the products I'm interested in. almost no TOTL IEM passes such criteria, so looking on the bright side, I'm saving money.

    and yes some DAPs and portable amps handle high sensi low impedance IEMs much better than others. my old Lekerton amp has low gain, and low noise at low voltage(it becomes pretty high when pushing to the max, but by then we're not using IEMs anymore but probably trying to drive some headphones loud enough, so the issue with high sensitivity is gone). it works pretty well for my use and I've kept it for the last few years for that reason. I simply never felt that I needed another one. but I'm not even sure that the company still exists, so I would suggest to go look for more recent products. I'm sure many IEM owners can suggest low noise amps and DAPs. and of course, you can always go read @shigzeo posts and blog, if he says that something doesn't hiss, it's quiet for sure.
    Last edited: Aug 6, 2019
  8. bigshot
    I'll stick with stuff you plug in and it just works!
    Thanks guys! I'm going to try iEMatch and check more portable AMPs.
    BTW, with my Schiit Magni 2U there is no hiss at all.
  10. bigshot
    It sounds like your problem is solved. Glad for that!
  11. PDVJAM
    Well, it does not yet, coz Magni is definitely not a portable AMP:) But I have already bought iFi iEMatch, it will arrive in a week or two. Then I'll check if it works...
    But thanks everyone for clarifications! :thumbsup:
  12. dazzerfong
    I had an iEMatch for my CA Polaris (before I promptly destroyed the jack by sitting on it :frowning2: ).

    Yes, it does reduce the hiss. Before, the Polaris damn near hissed on everything; with it, it stopped.

    Does it change the sound? Not really, but it's hard to volume match it coz everything just go so much quieter. I went from maybe a 20/100 on my volume dial on my phone to 70/100 when the iEMatch was set to -24dB.

    So rest assured, it'll stop the hissing. However, as for the sound signature, I think that one depends on your IEM because the effective output impedance on the iEMatch is ~1.1 ohm.
  13. bigshot
    I would imagine that if you can get rid of the hiss, your impedance is correct and it should perform to spec.
  14. dazzerfong
    Damping might be approaching severity if your IEMs have ridiculously low impedance. Thus why there's a potential for sound to be impacted.

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