Emotiva XMC-2 Review (AV Processor)

[Loron]

I think you have valid reasons and questions. But you are aiming them possibly in the wrong place. Amir does all this out of his pocket and the generosity of members. ASR has no commercial adds or Corporate Sponsors and we owe alliance to only our Membership.

I totally agree and that is why I rely on ASR. I am not questioning ASR. I am questioning the others….. I explicitly said that on other forums. ASR is my go t website Because there is no conflict of interest.

 

[DonH56]

I downloaded and skimmed through Lonnie's last data sets for production RMC-1 and XMC-2 units. They are very tightly matched as he said, and met their specs. The specs are at -20 dBFS so I suspect that is the main difference in distortion. I asked about one graph I am not sure I understand; it shows a THD sweep from 5 Hz to 20 kHz showing a significant rise as frequency drops and a sharp cut-off around 12 kHz or so.

It is their data and I am not sure about posting the files on another web site; I would rather they said it was OK first.

 

[garbulky]

I downloaded and skimmed through Lonnie's last data sets for production RMC-1 and XMC-2 units. They are very tightly matched as he said, and met their specs. The specs are at -20 dBFS so I suspect that is the main difference in distortion. I asked about one graph I am not sure I understand; it shows a THD sweep from 5 Hz to 20 kHz showing a significant rise as frequency drops and a sharp cut-off around 12 kHz or so.

It is their data and I am not sure about posting the files on another web site; I would rather they said it was OK first.

Am I missing something? What's the deal about -20dbfs? Aren't DACs supposed to deal with 0db signals? Who else tests at -20dbfs?

 

[Loron]

Am I missing something? What's the deal about -20dbfs? Aren't DACs supposed to deal with 0db signals? Who else tests at -20dbfs?

Agree. I guess that is the way they found to get better results. Initial Emotiva results at 0 dB showed a 85 dB SINAD. Since then they are just avoiding questions and changing the way they performed the test. Units have also been changed to dBV instead or dBrA. I know these are settings that can be done in the audio precision software but it is over my head.
i just know that I often listen at higher volume than -20 dB because of my amp gain, my speakers efficiency and the Dirac Live calibration effect on volume.
Obviously Emotiva is doing all they can to prevent easy correlation. Sad! Feels like a guilty plea.

 

[sam_adams]

Our good friend Zed Brookes weighes in on digital levels that includes a helpful graphic. @amirm may also wish to comment on whether or not this has any bearing on measurement levels when testing DACs. The argument can be made, also, for testing DACs with a 997 Hz signal instead of 1 KHz based on AES Standard Method For Digital Audio Engineering — Measurement Of Digital Audio Equipment, AES17-1998 (r2004).

 

[DonH56]

I found that confusing as well, and the only explanation I recall in the thread is that it is more "real-world levels". I am used to testing data converters at 0 dBFS, or often at -1 dBFS to provide about 10% headroom, as is pretty standard in the industry. You should get the best performance at full-scale, but of course the analog stages will exhibit lower distortion at lower levels. Since there are gain stages and such I do not know exactly what -20 dBFS means through the processor or at the DAC's output (if one in the tested configuration), and of course it depends on the volume setting. Their report mixes and matches various units like dBFS, dBV, dBmV, and dBm (?) and I have not spent the time to try to decode the levels. On one page the spec is Watts (Output Power) and the units are ohms, hmmm... I think it is a reference impedance but again I have not pored through it all and certainly do not know their test methodology. They list analog in/balanced output with generator level of 1 Vrms and THD measures around 0.03% but I am not sure what the output level is. Balanced input says generator level 200 mVrms with a spec limit of 0.03% THD+N at the output but not exactly the output level (is it unity gain?) And so forth.

It is an internal report and frankly I am surprised they put it up. Very cool, but they may regret all the questions it generates. Amir would know more since he is familiar with AP's parameters and reports (and I am not).

If the argument is that input and gain settings were not appropriate it may take a bit to find out exactly what was different. It would be nice to nail down exactly the output level for -20 dBFS input.

 

[jkcashin]

Oh come on. Emotiva needs to reach out instead of freezing threads. Deep water without swimming lessons or a life jacket.

It got locked temporarily, by a volunteer moderator, not an Emotiva employee, and because the conversation had devolved. It was unlocked less than 8 hours later.

UPDATE: OK I see what you mean... there was two threads, but they got merged into one making it appear like one of them was deleted. The consolidated thread was temporarily locked as I explain above.

 

[Loron]

Our good friend Zed Brookes weighes in on digital levels that includes a helpful graphic. @amirm may also wish to comment on whether or not this has any bearing on measurement levels when testing DACs. The argument can be made, also, for testing DACs with a 997 Hz signal instead of 1 KHz based on AES Standard Method For Digital Audio Engineering — Measurement Of Digital Audio Equipment, AES17-1998 (r2004).

Thanks! Very interesting. I learned a lot. There will be some good getting out of all this… -)

 

[Goodfellas27]

Full measurements by Emotiva at -20 and not 0 like Amir tested.
Loanne from Emotiva says -20 is the output of almost all consumers products.

 

[Colonel7]

I wasn't not appreciating the article. But I'm just saying it wasn't YOUR setup. It was a description of how things are done on a similar topic.
The link doesn't have to be entertaining but I'm sure you have some rigiorous ways you do your thing, so document, provide photos, measurements of your own equipment etc.
I think you do know what you are doing. As you mentioned, your measurements have been duplicated. But it's not for people that think you know your stuff. It's an easy link for people to verify that yes, you DID have things hooked up right. Your calibrations were set like this. It can be the driest boring most detailed thing. An info dump if you will. Otherwise, you're going to have people just coming here and calling you out on stuff that could have been taken care with one detailed link.
BTW Your AP project file is that way too big to post with your review?

I think you should direct your need for attention to detail to the manufacturer. Including pics and serial #s. And yes I'm just kidding

 

[garbulky]

Full measurements by Emotiva at -20 and not 0 like Amir tested.
Loanne from Emotiva says -20 is the output of almost all consumers products.

Trying to figure out what that means? Like -20db is a digital PCM signal to the XMC-2? Like they are limited to -20 db somehow?

 

[garbulky]

I think you should direct your need for attention to detail to the manufacturer. Including pics and serial #s. And yes I'm just kidding

Sadly Emotiva has gone very lax on releasing their AP data. They used to frequently. I have badgered them about it from time to time.

 

[David_M]

Trying to figure out what that means? Like -20db is a digital PCM signal to the XMC-2? Like they are limited to -20 db somehow?

No, Lonnie said that most users have the volume of their pre-pros set at about -20dB for comfortable music and movie playback. Maybe that's the case in his home but the volume you set depends on several things, notably the sensitivity of your power amplifier and the efficiency of your speakers. His reasoning was to test at this volume level instead of at the 0 dB level, which is the screaming, ear-bleeding, mentally aggravating volume level. At this 0dB level, you are driving most (if not all) commercial power amps at their rated power outputs constantly, which isn't good for your hearing or the drivers in your speakers, let alone your family members and neighbors.

Imagine setting your volume level at 0db for your 300 W/Channel power amp driving your moderately sensitive speakers at 90dB/m/watt. 300 W = 24.8 dBW, ==> SPLs of 90 + 24.8 = ~ 115dB will be generated, which, is way too uncomfortably loud for most sane people. Remember standing next to a running commercial jet engine produces SPLs of 120dB or more. 115dB is no joke!!!

 

[Goodfellas27]

The input signal the XMC-2 is getting from the AP is set at -20, if I am not mistaken. Amir uses 0db test tones unless otherwise noted.

Trying to figure out what that means? Like -20db is a digital PCM signal to the XMC-2? Like they are limited to -20 db somehow?

 

[GXAlan]

Full measurements by Emotiva at -20 and not 0 like Amir tested.
Loanne from Emotiva says -20 is the output of almost all consumers products.

-20 means that you are seeing 65dB averages with 85dB peaks.
+0 means that you are seeing 85dB averages with 105dB peaks.

This is the old THX Reference Level discussion.

Not everyone listens at reference level but one would expect something in this price range to be used with amplifiers and speakers that are appropriate.

You will see this in any auto calibration tool where it seems like nothing is set at +0 dB. If you have super high input sensitivity and super high efficiency speakers, you will see everything turned down.

 

[amirm]

Full measurements by Emotiva at -20 and not 0 like Amir tested.
Loanne from Emotiva says -20 is the output of almost all consumers products.

Thanks. What they have post is the production test "go/no go" automated sequence. This is usually different than engineering ones which is what I run.

Anyway, they do test at -20 dBFS which actually works against them as that increases contributions from noise. Here is a snapshot from the report:

Channel 1 THD+N converted to SINAD is 77 dB. Channel 2 is 80 dB. They have set the limit to just 50 dB(0.3%). They are assuming that if anything is wrong with the manufacturing, SINAD sinks massively so this catches it. What it won't catch is variations in performance.

Anyway, this kind of report is not a proper answer to the question asked.

 

[TimoJ]

Anyway, they do test at -20 dBFS which actually works against them as that increases contributions from noise.

Do you have any idea why they say that most devices (connected to processors) output at -20dBFS level? Looks like they have optimized performance to -20dBFS max. input level and above that it gets bad and "musical". Sounds very odd.

 

[RichB]

It is quite common for music files to be recorded t or near 0 dBFS. The is part of the loudness wars.

I don't understand how this is not a valid or even common file. An AVR/AVP can perform PEQ or REQ digitally but must attenuate the source digitally to allow for boosts. This should not be necessary pure direct or Reference Stereo mode.

I don't get how -20 dBFS is typical for music files and why a processor should not be measured as they are here with full scale digital signals.
What am I missing?

- Rich

 

[Lsc]

All this is way over my head. Lonnie said he would be willing to send all 3 processors to ASR. He also said the RMC1 and the XMC2 have very similar (almost exact) performance and showed some test results reflecting this.

Are we saying “hey you designed the processors and are saying the processors are equal across them for LCR, but you are wrong”? Well, I feel very comfortable taking his word and his results that back his statement. Now if this was big Dan saying this then yes, I’ll take it with a grain of salt but Lonnie, he is different and is a straight shooter.

Why doesn’t ASR take his offer?

Man this nerd vs nerd stuff is for the birds . But this is the most attention the XMC2 has received lol.

 

[David_M]

Do you have any idea why they say that most devices (connected to processors) output at -20dBFS level? Looks like they have optimized performance to -20dBFS max. input level and above that it gets bad and "musical". Sounds very odd.

See my post above https://www.audiosciencereview.com/...review-av-processor.26378/page-17#post-906491