Emotiva RMC-1+ AV Processor Review

[jkim]

Last post from me on this thread, I promise. And thanks to @Rja4000 who indirectly helped, by providing me with key information on the same, which triggered the below.

I wanted to come back on Dynamic Range, and how to compute it, with some illustrations too as this is interesting, I think. For the purpose, I used a Topping D50III, which Amir reviewed. This device was measured to have a 126dB DR. My own ADC does not go that deep, as it's not a High End Audio Precision, but the below results are still relevant.

The Dynamic Range is measured, per the AES standard, this way:

• Dynamic range: This test measures the ratio of the full-scale level at the output of the EUT to the weighted noise and distortion level in the presence of a low-level signal. It includes all harmonic, inharmonic, and noise components. The test signal shall be a 997 Hz sine wave with a level of -60 dB relative to the maximum input level (see 6.2.1). The output of the EUT shall be filtered with the standard low-pass filter (see 5.2.5) and the standard notch filter (see 5.2.8), whose center frequency is set to 997 Hz. The output of the standard notch filter shall be filtered with the standard weighting filter (see 5.2.7). The rms level of the final filter output shall be measured. The dynamic range shall be the ratio of the maximum output level (see 6.2.6) to this measured level. It is reported as dB CCIR-RMS.

The above is how Amir measures the DR, with his Audio Precision. From the above, it means the DR is computed from the SNR in the presence of low level (-60dBr) signal. And so the DR = Measured SNR + 60dB. The below measurements I performed respect the above, 997Hz frequency @-60dB relative to max, notch and low-pass filter, only the weighting filter (or no filter) is changed for educational purpose.

So, let's measure the Topping, first unweighted, showing a DR of 129.7dB:

View attachment 478501

Next with the obsolete A-weighting, showing a DR of 132dB::

View attachment 478503

You see the correction A-weigthed curve applied to the signal. It lowers low and high frequencies.

And last, with the CCIR-2k curve, which should be used, and that gives me 122.4dB:

View attachment 478506

Note the emphasis put at 6kHz by the CCIR curve.

For the record, Amir found 126dB of Dynamic range for the Topping (balanced output), so my interface is shy of 4dB compared to the AP, which is reasonable at this very low level.
As a matter of facts, my Cosmos Grade0 is given for 129dB(A) and 132dB(A) in mono mode. So, seeing it reports 132dB(A) in this test not only means I get there indeed, but confirmation that the Topping goes below that, as Amir showed.


Conclusion

Vendors like the A-Weighting curve for the obvious reason it provides them with the best results. But the new standard is the CCIR curve, as the AES mandates.


PS: I included the two CAL files for those using REW, for the CCIR and A-weighted curves. I created them with my AI best friend and checked it did no go rogue (it did for the A-weighted curve, too many prompts were necessary to make it right, it would have been faster to do it myself ). They are limited to 20kHz, FYI.

@NTTY

For CCIR-2K (aka ITU-R 468 2K) weighting, you simply applied it as a calibration file in REW, didn't you? Then, when calculating THD+N, REW apples the calibration to the entire spectrum INCLUDING the fundamental tone at 1 kHz (it should not), and ends up overestimating THD+N. In your above example, actual CCIR-2K-weighted THD+N should be -62.4 dB -5.6 dB = -68.0 dB. So, the CCIR-2K-weighted DR should've been 68.0 + 60 dB = 128.0 dB.

You can easily see why the calculation is incorrect by applying the original CCIR-1K calibration to REW (simply add 5.6 dB to all frequencies). You will get exactly the same THD+N as you got from the use of CCIR-2K calibration in REW, which is wrong.

I saw your SMSL PL200 review also included CCIR-2K-weighted DR. That needs to be corrected, too.

 

[NTTY]

Oops, I realized from your message that I'm on the "1k" curve, as you can tell from the cal file.
So I got it wrong between the curve I said I used and the one I actually used. Shame on me.
Thank you for posting this!

That's what the AES17-2020 says, and I need to correct my curve accordingly. Either I redo all measurements or I adjust as you mention (in the past it was possible to apply a cal file after the facts with REW, but that option seems to have disappeared from the beta version that I use).

I'll be working on that tonight.

That said, applying the curve with cal file in REW is valid, even if it virtually decreases the 1kHz fundamental like the rest, I think. The 0dB reference is set at the max input level of the DUT with a sine tone of 997Hz, per the AES. For a DAC, this is theoretically 0dBFS sine tone generated. Amir applies his own rule that is 4Vrms output from XLR and 2Vrms output from RCA of DAC, implying sometimes to set the 0dB at -2dBFS input of the DAC to get to that 4Vrms output.
I apply the same for a DAC, but not for a CD player, where I always use the 0dBFS as the 0dB reference, what ever voltage the CD player would output.
So, I don't think the -5.6dB should be disregarded for the fundamental, else the 0dB reference would be -5.6dB below at 1khz, and so that would not change the SNR.
I'll anyways play with all of that tonight.

Thanks again!

 

[jkim]

So, I don't think the -5.6dB should be disregarded for the fundamental, else the 0dB reference would be -5.6dB below at 1khz, and so that would not change the SNR.

A calibration file in REW works as intended for the purpose of soundcard or mic calibration. There's no problem with that. The point is that it is not for noise weighting which is a different task. The calibration should apply only to the noise, not to the fundamental tone. If noise weights are normalized at 1 kHz (like A-weighting), then REW calibration works. Otherwise, we should manually compensate for a difference at the fundamental tone frequency.

 

[NTTY]

Hi jkim,

Thanks for that. Indeed, I did not read the AES this way. But in lights of your input, it indeed concurs with the text of the AES: "This test measures the ratio of the full-scale level at the output of the EUT to the weighted noise and distortion level in the presence of a low-level signal"

So, I adapted the CCIR-2k curve in the cal file to add +5.6db (I did it from 990Hz to 1010Hz).

Here you go with the results (with the Topping D50III).

CCIR2k no compensation of the fundamental (like I initially did):

Here the DR is 62.6 + 60dB = 122.6dB, and that was wrong.

With the compensation of the fundamental:

Now the DR is 67.8dB + 60dB = 127.8dB. Amir found 126.4dB so I am now very close, which also confirms the measurement.

I also did again the standard SINAD measurements, and I found 123.7dB (average of the two channels), where Amir got 122.7dB and and @Rja4000 got 124.6dB.

So me seeing 1dB better, in DR and SINAD than Amir, makes perfect sense.

Thanks for the feedback!

PS: I attached the cal file for DR calculation. File removed, I need to update it!

 

[jkim]

Hi jkim,

Thanks for that. Indeed, I did not read the AES this way. But in lights of your input, it indeed concurs with the text of the AES: "This test measures the ratio of the full-scale level at the output of the EUT to the weighted noise and distortion level in the presence of a low-level signal"

So, I adapted the CCIR-2k curve in the cal file to add +5.6db (I did it from 990Hz to 1010Hz).

Here you go with the results (with the Topping D50III).

CCIR2k no compensation of the fundamental (like I initially did):

View attachment 480278

Here the DR is 62.6 + 60dB = 122.6dB, and that was wrong.

With the compensation of the fundamental:

View attachment 480279

Now the DR is 67.8dB + 60dB = 127.8dB. Amir found 126.4dB so I am now very close, which also confirms the measurement.

I also did again the standard SINAD measurements, and I found 123.7dB (average of the two channels), where Amir got 122.7dB and and @Rja4000 got 124.6dB.

So me seeing 1dB better, in DR and SINAD than Amir, makes perfect sense.

Thanks for the feedback!

PS: I attached the cal file for DR calculation

Great. How did you get these higher-resolution CCIR weights? Used a modeled formula?

 

[NTTY]

Great. How did you get these higher-resolution CCIR weights? Used a modeled formula?

I asked copilot to do it for me

 

[NicS]

There are some interesting claims being made on the Emotiva forum that I'd like to stress test here. This is not means to stir trouble. I think for those not privy to the Emotivalounge, it would be great to get some feedback on some of the things I've read that, for me at least, throw up red flags.

"I personally think the SINAD ranking is dumb and don't see the point of it."

"Amir does not follow any standardized test procedure that you will find from a manufacturer."

"Amir's test does not follow any of [the AES] standards."

"[Amir's] claim of horrible noise is quite frankly laughable."

"The idea that a noise floor that is -60 db down at 90Khz could in some way affect the IMD of an amp is ludicrous."

"Amir's goal is to get people to visit his website... as much as possible... as often as possible...
(I don't know if his site is "monetized" or if its just "a hobby" or if he also "really just wants to inform people".).
But, either way, we all know that "stirring up controversy" is a great way to "encourage more viewer interaction"."

 

[amirm]

"Amir's test does not follow any of [the AES] standards."

Neither does Emotiva seeing how they don't publish any AES test results. Or test results in general.

My testing has been published at AES: https://aes2.org/publications/elibrary-page/?id=22278

Comprehensive Objective Analysis of Digital to Analog Conversion in Consumer and Professional Applications​

A six-year project measuring performance of over 400 Digital to Analog Converters (DACs) brings insight into the range of performances and prices in this device category. Measurements show that full audible transparency has been achieved in many DACs at reasonable costs, based on off-the-shelf IC DACs. Consumer DACs lead in this regard over those intended for professional applications. Custom/discrete DACs have not been seen to bring an advantage in either performance or cost. Suggestions are made to improve functionality and performance of measurement equipment and standardization of output voltages in DACs.

Author (s): Majidimehr, Amir
Affiliation: Audio Science Review (See document for exact affiliation information.)

 

[amirm]

"I personally think the SINAD ranking is dumb and don't see the point of it."

This is a measurement that has been a standard for almost a century! It measures combination of noise+distortion. After so many decades, one would think that every company production audio products would care to optimize it. And it is not as if you are getting a discount for lower SINAD. You are being charged the full amount whether SINAD is horrible or great.

 

[amirm]

"Amir does not follow any standardized test procedure that you will find from a manufacturer."

No manufacturer follows any "standardizes test" in AV world. If one is lucky, a few numbers are thrown out, devoid of any test conditions. If not, what substitutes as spec these days is how many HDMI connectors you get and the box size.

Fortunately, some have paid attention and adopted measurements similar to what I run. Prime example is Emotiva's competitor, Denon & Marantz. Not only did they adopt ASR measurements but used them to sharply increase the performance of their products.

 

[amirm]

"The idea that a noise floor that is -60 db down at 90Khz could in some way affect the IMD of an amp is ludicrous."

The IMD test is run at sample rate of 48 KHz which is extremely common in movie content. Its bandwidth is half of that or 24 kHz, not 90. There, the Emotiva produced far more noise than a $20 phone dongle:

The dashed orange is the said dongle. Problems like this are readily found and fixed if a modicum of effort was made to produce high fidelity equipment.

If the poster is referring to THD+N wideband test, the problem there is rising noise floor starting at just 10 kHz:

I have never seen such a rising curve in any DAC let alone in an expensive processor. Something is seriously wrong here and needs to be investigated instead of acting as PR person for the company.

 

[amirm]

"Amir's goal is to get people to visit his website... as much as possible... as often as possible...
(I don't know if his site is "monetized" or if its just "a hobby" or if he also "really just wants to inform people".).
But, either way, we all know that "stirring up controversy" is a great way to "encourage more viewer interaction"."

ASR has no monetization of any sort. As such, it doesn't matter if I get more views or not. Products like the Emotiva processor are extremely time consuming to test due to high level of functionality and complexity. Even if I did have some monetization, I would be lucky to make a few cents per hour seeing the limited number of people who are interested in expensive AV processors.

Negative reviews like this are always met with toxic reactions, draining any positivity one would want in life. It usually creates a ton more work for me like answering unfounded claims like this. Instead of encouraging for profit companies to do better, upstanding customers choose to take the side of less than good engineering as if they are getting something extra for the faults that are found. Fortunately many people do appreciate the work which encourages me to keep doing this.

 

[NicS]

Thank's Amir for this response. It's very much appreciated.

I admire Emotiva as a company. I like what they are trying to do and I feel happy supporting them. In this instance I feel let down by their attitude and reaction to your assessment. They are ignoring (at their own peril) the number of people who consider ASR a reliable source of information, that also buy their equipment. I'm sorry that they did not take up your offer of support. Their reaction has stalled my intention to perform the upgrade of my RMC-1L to the "+" version. I'm now considering the CR8 upgrade, which leaves the old audio board in place.

 

[mdsimon2]

@amirm

Any chance you still have the unit? I was looking at the IMD sweep and thought the slope of the curve was unlike anything I had seen before.

Comparing the Razer and DX3 Pro, it is clear that the Razer has higher noise and has roughly a constant vertical offset compared the DX3 Pro, at least until distortion starts to take over at high generator level. It is odd to me that the Emotiva starts off higher noise than Razer at low generator level but then gets close to the DX3 Pro at high generator level.

Could you post the -60 dB FFT to see if there is anything visually odd going on?

Michael

 

[ryan74701]

@amirm dropping the mic on Emotiva

I do not post here hardly ever but after visiting the Emotiva forum just to read what they’ve been saying in regards to this review and what a bunch of…


For Five F****** thousand dollars this AV processor should have tested at the very top of its class.

What a pile of junk, tie it to a chain and use it as a boat anchor.

 

[Hart]

There are some interesting claims being made on the Emotiva forum that I'd like to stress test here. This is not means to stir trouble. I think for those not privy to the Emotivalounge, it would be great to get some feedback on some of the things I've read that, for me at least, throw up red flags.

"I personally think the SINAD ranking is dumb and don't see the point of it."

"Amir does not follow any standardized test procedure that you will find from a manufacturer."

"Amir's test does not follow any of [the AES] standards."

"[Amir's] claim of horrible noise is quite frankly laughable."

"The idea that a noise floor that is -60 db down at 90Khz could in some way affect the IMD of an amp is ludicrous."

"Amir's goal is to get people to visit his website... as much as possible... as often as possible...
(I don't know if his site is "monetized" or if its just "a hobby" or if he also "really just wants to inform people".).
But, either way, we all know that "stirring up controversy" is a great way to "encourage more viewer interaction"."

People can get very tribal when they are protecting their brand. Like sports and politics it becomes more about your "team" winning than rational thinking.

 

[amirm]

Any chance you still have the unit?

No, I shipped it to its owner last week. On that IMD test, there could be other issues than pure noise seeing how the curve is not a straight downward slope.

 

[mdsimon2]

The IMD test is run at sample rate of 48 KHz which is extremely common in movie content. Its bandwidth is half of that or 24 kHz, not 90. There, the Emotiva produced far more noise than a $20 phone dongle:

I've always wondered what the bandwidth was for this test as it has a noise component. From your quote above it sounds like the DAC is running at 48 kHz and measurement bandwidth is 24 kHz, is that correct?

Michael

 

[xaxxon]

Just one more reason against buying separates...

This has nothing to do with this not having an amplification stage. ???

 

[masterhw]

This has nothing to do with this not having an amplification stage. ???

one would expect a dedicated processor to at least perform its reduced duties relative to an AVR more competently than one. but there are many such cases where it does not. so it is a knock against the class of AV separates.