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Post by heroesunplugged on Oct 9, 2017 0:45:14 GMT -5
There is some pretty severe distortion that is coming through when playing tracks that are primarily piano. I've heard the distortion on 3 different pair of speakers. It's bad enough that I don't want to play these tracks. Never heard this through other receivers or preamps. I swapped out the amp, cables (same with either RCA/XLR), CD player, and ran a vintage Pioneer SA-1080 as a preamp in place of the XMC-1. It is more severe when speakers are set to small, and using my M&K LCR-750s, than when using the Large speaker setting. I'd figure the Large setting would have more potential of being problematic.
Also, using Stereo Reference lessens the amount of distortion. The Speaker Setup 2 (small speaker setting), using Stereo, is set flat so EQ wise they're the same. It sounds like the tweeter is overloading, but it doesn't happen with some piano tracks and does on others. This also happened when using a pair of Koss CM-1020s (large speakers) and it seems like in both cases the distortion is heavier in the Right channel.
Is it possible that there is a resonant frequency that is peaking the digital circuit inside the XMC-1? It's consistent regardless of speakers. This happens with my Polk Audio SDA-SRS 3.1TLs too. The M&Ks and Koss are the more revealing speakers and seem to have the most distortion as a result. The Polks are less detailed so that may be the reason it doesn't seem as bad, when they're in the setup. It occurs mostly on the attack than the sustain and is very brief. Any ideas?
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Post by 405x5 on Oct 9, 2017 7:11:59 GMT -5
Swap your amp. (Test) if at all possible
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Post by 405x5 on Oct 9, 2017 7:14:49 GMT -5
On the XMC, try resetting the filters?
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Post by vcautokid on Oct 9, 2017 8:10:18 GMT -5
It sounds like a very node that was set in the XMC-1. If you ran Dirac you have got a hot node possibly. Setting your filters to default is a great start, then maybe running Dirac again.
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Post by Casey Leedom on Oct 9, 2017 11:39:21 GMT -5
Well recorded piano music can be pretty brutal on systems which are misconfigured. The set of harmonics that a piano can generate go up into the very high harmonic space.
The description of your issues seems to implicate any kind of processing going on in the XMC-1. Setting your speakers to "Small" involves a high-pass filter. And setting it to "Stereo Reference" should eliminate almost all processing, but I'm not familiar with the XMC-1 and there may be an even less processed path like "Direct". For instance, is there a mode which completely bypasses DIRAC?
Finally, don't neglect your room! If you have a lot of hard, reflective surfaces, an actual piano being played in the room would sound horrible.
Casey
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Post by heroesunplugged on Oct 9, 2017 11:54:54 GMT -5
Swap your amp. (Test) if at all possible Never applied Dirac. This is the first thing I tried since I have 2 SA-250s. Also made adjustments to input level settings and lower setting results the same at a lower level. |
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Post by heroesunplugged on Oct 9, 2017 11:55:50 GMT -5
On the XMC, try resetting the filters? Saved settings and did factory reset with no luck. |
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Post by 405x5 on Oct 9, 2017 12:19:40 GMT -5
I play a ton of piano tracks with the XMC.....everything from 1990’s CD’s to lossless LANG LANG bluray concerts and have never experienced such a thing. Time for an Emotiva tech support session me thinks.
Bill
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novisnick
EmoPhile
CEO Secret Monoblock Society
Posts: 27,223 
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Post by novisnick on Oct 9, 2017 12:25:13 GMT -5
Check your speaker wires please. Even one stran out of place can cause all kinds of problems 😁
Hope this cures it!
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Post by heroesunplugged on Oct 9, 2017 13:08:15 GMT -5
It sounds like a very node that was set in the XMC-1. If you ran Dirac you have got a hot node possibly. Setting your filters to default is a great start, then maybe running Dirac again. I haven't used Dirac. Reset to factory default and running completely flat (filters not adjusted in Stereo mode) worsens the resonances that are involved - causing the distortion. Most of a song is fine, but there are certain cords/harmonics that set this off. Running my original, filtered, Speaker 1 setting with speakers set to Large, actually lessons the ill effect. I'll have to play with the filters and perhaps nail down the frequencies that are involved. As a side note: From use of Pioneer's MCACC room correction, in the past, the M&Ks have always had the least amount of correction needed. The trim levels and the equalization curves were minor compared to other speakers within their usable range. I'm usually concerned with sending too much bass to the LCR750s, but in this case it is not the lower registers, but likely in the mid-band region of the piano that distortion is present. Doesn't seem problematic on tracks with more saturated, multi-instrument arrangements that are perhaps louder and have more complexity. |
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Post by heroesunplugged on Oct 9, 2017 13:52:23 GMT -5
One of the most obvious tracks is from Blue Stone's Breathe, "New Beginning" (Track 15). Maybe having a specific track will clarify. Volume is set to -27/-28 using RCA cables to an Emotiva SA-250 amp using the 29 dB gain setting (should be the same as any Gen 2 or 3 amp). Speakers set to small using the Toslink/optical input 1 with no filtering adjustments using Stereo Mode. Checked cables for "strands out of place" per novisnick's suggestion.  I can hear the distortion seated or at close monitoring distance, so it isn't a room node or something resonating nearby. It is radiating directly from the speakers. I also brought in an LCR750 center channel and it performs the same. Perhaps somebody else can find out if they get the same results in their system? |
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Post by heroesunplugged on Oct 9, 2017 14:12:46 GMT -5
Well recorded piano music can be pretty brutal on systems which are misconfigured. The set of harmonics that a piano can generate go up into the very high harmonic space. The description of your issues seems to implicate any kind of processing going on in the XMC-1. Setting your speakers to "Small" involves a high-pass filter. And setting it to "Stereo Reference" should eliminate almost all processing, but I'm not familiar with the XMC-1 and there may be an even less processed path like "Direct". For instance, is there a mode which completely bypasses DIRAC? Finally, don't neglect your room! If you have a lot of hard, reflective surfaces, an actual piano being played in the room would sound horrible. Casey Agree that piano can be difficult to produce or record, but it's not a matter of tonality, it is distortion/breakup? Tonally it's great until a particular resonance/s come into play, and then it sounds awful. |
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Post by 405x5 on Oct 9, 2017 14:31:19 GMT -5
IMHO,
You could get someplace quickly with a simple call to technical Emotiva support, rather than trying to get other forum members to try and recreate your problem?
Often we put our heads together to solve problems and such, but this sounds beyond that and you’ve pretty much covered the usual suspects.
Bill
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Post by heroesunplugged on Oct 9, 2017 14:53:59 GMT -5
Bill,
Sure, I'll just go directly to the source, but figured that there might be somebody else here that has had a similar experience. And not sure if this is possibly related to the noise between tracks, like dithering effects, digital artifacts or timing issues. Otherwise the XMC-1 sounds excellent and so do the M&Ks.
Thanks for all of the input.
Chris
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KeithL
Administrator 
Posts: 9,941
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Post by KeithL on Oct 9, 2017 16:08:45 GMT -5
I've spoken to the OP on the phone about this... and it is a very interesting puzzle. When the XMC-1 is operated in Reference Stereo mode there is no processing applied to the audio signal. If the input signal is digital, then it is being converted to analog by the XMC-1's DACs, but no other processing is applied. However, if the input signal is analog, then it REMAINS analog throughout it's trip through the XMC-1, and is NEVER converted to digital at all. The OP informs me that this distortion is still audible, even when using the analog output of the CD player, connected to the analog input on the XMC-1. This essentially rules out anything to do with the XMC's DACs or digital circuitry. And, while it's possible to drive the XMC-1 into clipping if you try hard enough, the type of distortion you would get doesn't seem to fit this description. I'm going to look into this and see if I can at least get a little closer to figuring out what's going on.  |
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Post by vneal on Oct 9, 2017 16:48:41 GMT -5
If you had not switched your speakers out I would say it is a blown tweeter
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Post by Casey Leedom on Oct 9, 2017 18:06:25 GMT -5
I'm still going with room distortion as a cause which should be investigated.
Casey
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