Anthem MRX 510 7.1 A/V Receiver Review Highlights
Anthem has kept their receivers focused on audio quality above all else. Instead of loading them with features many people won’t use, since you don’t need a 13th way to stream Internet Radio, they have kept it focused on performance. The most notable feature on all their receivers is the full version of Anthem Room Correction (ARC). As detailed for Secrets by Dr. David Rich, ARC stands above other affordable room correction systems available today. Combining this with 100 watts per channel for seven channels produces a receiver that can serve as the center for a quality home theater system.
Anthem MRX 510 7.1 A/V Receiver Highlights Summary
- Anthem Room Correction (ARC) 1M built-in
- 7 channels with 100 watts each
- 8 HDMI Inputs, 2 Outputs with 4K scaling
- No streaming services or DLNA support
Introduction to the Anthem MRX 510 7.1 A/V Receiver Review
The original Anthem MRX receivers are performance-focused compared to many other products out there. They lack some of the crazy features we see, like 11 channels of audio or 15 different streaming services, to focus on sound quality. In doing so they succeed thanks in large part to the inclusion of Anthem Room Correction (ARC). Even compared to its predecessor, the MRX 510 is a streamlined model. There is no Internet streaming and no obscure processing with fake height channels. iOS and Android control apps became available in August.
ANTHEM MRX 510 RECEIVER REVIEW SPECIFICATIONS
- Design: 7.1 A/V Receiver
- Power Output: 2 x 100 Watts, 5 x 75 Watts, 8 Ohms, 0.1% THD+N
- Inputs: 8 x HDMI 1.4a (7 Rear, 1 Front), 2 x Component Video, 1 x Composite Video, 3 x Optical, 2 x Coaxial, 5 x Stereo RCA
- Outputs: 2 x HDMI 1.4a, 7.1 Pre-out, 2 x Stereo RCA, 12V Trigger
- Dimensions: 6.5” H x 17.25” W x 15.63” D
- Weight: 30.2 Pounds
- MSRP: $1,599 USD
- SECRETS Tags: Anthem, Anthem MRX 510, Receiver Reviews, 2014, Anthem MRX 510 Receiver Review
Those features would take resources away from the amplifier and sound quality, because they would have a cost to implement. We all have a box, or two, or ten, that already stream Internet radio. Few of us have nine or eleven speakers or even the space for them. What we do have are listening rooms that aren’t perfect. They aren’t covered with acoustic treatments, and likely have a few sacrifices in the name of decor over acoustics. The Anthem MRX 510 makes a difference you can hear, at a price you can easily afford, and that you’ll appreciate every day.
Design and Setup of the Anthem MRX 510 7.1 A/V Receiver
The most notable new feature in the Anthem MRX 510 is ARC 1M. Unlike most room correction systems, Anthem uses your PC to calculate the corrections. Since your PC Is far more powerful than any receiver it can do more advanced calculations. Before, ARC required using the dreaded USB to RS232 adapter. Now ARC 1M connects over Ethernet so your laptop with Wi-Fi will handle it. Since you also need to plug the included calibrated microphone into your computer, it makes running ARC easier.
That Ethernet port also provides IP control for home automation systems like Control4. One shortcoming in the previous MRX receivers is the small number of HDMI inputs. The MRX 510 has rectified this with 7 HDMI 1.4 inputs on the rear panel and one behind a front panel. For those using legacy devices, there are two component inputs and a single composite video input that are converted to HDMI. There are 5 analog audio components, as people use those more than analog video today. The MRX 510 also has a 7.1 channel preamp output so you can use ARC with an external amplifier.
One thing that is not on the MRX 510 is any method of streaming music. There is no Bluetooth or AirPlay, and no support for media services or Internet Radio. Not supporting external services is understandable, as what is popular today might not be in a year. It would be nice to at least have DLNA support on-board for your local media files.
The amplifier section of the MRX 510 has ratings for two channels and five channels driven, a rarity today. For an 8 ohm speaker it will deliver 100 watts into a stereo configuration and 75 watts per channel for a five channel system.
The remote control is large with lots of buttons, as do most receivers, because they have lots of functions and choices.
Setup of the Anthem MRX 510 is a little different than other receivers I have seen. The only factory-assigned inputs are for HDMI 1, 2, and 3, as well as the FM and AM tuners. Every other input, from analog audio to using Audio Return Channel, you assign in the menu system. This works well to reduce confusion as it keeps your choices limited to what you are using. I’d remove the FM and AM turners by default as well, but perhaps more people use them than I think.
The real key to setup is using ARC. You can first use the Quick Measure to get your speakers in the best position. The microphone can do continual measurements while you move speakers around to try to find the most even response. Using this made it easy for me a position a set of speakers that I was reviewing for the most even frequency response.
ARC setup is fast and easy. It takes perhaps 15 minutes to measure the minimum 5 positions. You have two distinct settings, and each has speaker settings, crossovers, targets, and corrections. If you want to use your subwoofer for movies but prefer to disable it for music, that is easy to do. Since each input can have a one of these two ARC profiles assigned to it you can make that selection automatic as well.
Even if you don’t want to use ARC, you should set it up and then disable it. In our testing we found that the receiver performs best after ARC has run, even if you disable it. ARC also lets you save your measurements so you can come back and make adjustments on the fly. If you want to test a different maximum correction frequency, or level of room gain, you can do this from your PC and upload it in minutes. No other included room correction system lets you make adjustments as easy as ARC does.
I tested the MRX 510 in two different systems. One uses five Paradigm Millenia One speakers with an SVS PB-1000 subwoofer. The other uses Definitive Technology Mythos STS fronts, a Nine center, and Gem surrounds with a Power Sound Audio XS30se subwoofer. Installing and configuring the MRX 510, including running ARC, can be done in under an hour.
The Anthem MRX 510 7.1 A/V Receiver In Use
The most noticeable thing about ARC is the definition it brings to the soundstage. With ARC enabled it has a clear front that extends to the edges of the speakers, and then goes far back into the wall. Instruments have a much more precise location in this soundstage than is usual. I have had a wider soundstage before, but not one where you can locate the individual objects as well. Using wall-mounted speakers in my living room the depth is not as present, but the cohesion between the speakers and subs is.
“Lost Cause” from Beck lets his voice hang right between the centers, anchored to nothing but space. Guitars have a crisp, clean attack while the ambient sounds in the song hover around everyone in the mix. The HDTracks download of Kind of Blue shows how ARC can integrate a subwoofer with satellite speakers. A pair of Paradigm Millennia Ones and an SVS PB-1000 in my living room mate well. The lower octaves of a double-bass come from the soundstage and not the subwoofer.
The quiet countdown to start “Drive” from R.E.M. is easy to hear through the MRX 510. This subtle background is often lost unless you turn the volume up, but here it anchors into the left channel, clear as day. Driving small monitors like the Paradigm Millenia Ones or larger towers like the Mythos STS, the MRX 510 has the power to drive them.
Movies may benefit even more from ARC. 5.1 channel soundtracks have a cohesive soundstage. During Catching Fire, insects buzz all around my head while bass sounds reroute from monitors to the subwoofer. Center channel dialogue is clear and easy to hear, even when listening at levels below reference volume. When the cannon goes off to signify yet another competitor has died, it fills the room without overpowering it.
The SACD release of Pink Floyd’s Wish You Were Here helps illustrate the benefits of ARC. During the title track, turning ARC off causes a noticeable loss in sound quality. The bass becomes fatter and far less precise than with it enabled. The soundstage lacks the definition and clarity that it has with ARC enabled. With ARC disabled the surrounds become too loud and out of balance with the rest of the 5.1 channel mix as well. Without ARC the music still sounds good, but ARC turned on dials it in. This isn’t the fuzzy, diffuse sound that many room correction systems add. It is a clear, detailed soundstage that enhances everything it touches.
For audio quality from a receiver, there isn’t anything I can pick on the MRX 510 for. Anthem Room Correction 1M works very well, much better than other room correction systems do. The sound quality is as good as my Marantz AV7005 preamp, and the Anthem costs the same while including an amplifier section. I haven’t heard a preamp or receiver that costs less than $3,000 that has more clarity, but the MRX 510 has better room correction. If I want the best sound quality, the MRX 510 is going to provide great results.
The Anthem MRX 510 7.1 A/V Receiver On The Bench
David A Rich Ph. D.
We want to thank Audio Precision for the loan of the test equipment used in this review to Chris Heinonen who did the measurements
AC Watts are measured in average power. RMS Watts do not exist. Only AC current and AC voltage are RMS quantities. To save space average Watts is abbreviated as Watts below.
This product can be used in many application spaces hence I am providing more measurements than normal. It can be used as a full AVR in both stereo and multichannel. In stereo the performance of the ADC is important since ARC requires the signal to be converted to digital first.
The use of stereo only makes sense to get an excellent PC coefficient calculation based room correction system although most would choose the MRX 310 for that deployment. PC coefficient calculation based stereo room correction systems alone cost $1000. The problem with the MRX is you need a small TV to see the GUI screens. Those TVs cost more that 32 inch sets and you should see the look you get from a Walmart sales person when you ask to see one.
When using the MRX 510 as Pre/Pro we have two ranges to consider. It depends on how large your external power amp is. First let us deal with the idea that you can hook any external power amp you want to the preamp outputs of an AVR and expect it to go to full power. It does not work like that. When the preamp outputs get to the level that the internal AVR power amp is goes into clipping the AVR may go into protection even with no load. We have seen this with two brands.
The MRX 510 does not go into protection. 2VRMS, which is the standard level we use for stereo preamp testing, will give you 200 Watts average in to 8 Ohms for an external power amp with a standard gain of 20V/V or 400 Watts average with a THX gain of 28V/V. The 2VRMS level is what I will be using for some of the measurement results below. The preamp outputs can run past 2VRMS although we did not test above that voltage. Nothing much changes on the power amp side of the MRX 510 above 2VRMS as long as no load is attached.
The internal power amp is producing square waves when clipping and the harmonics couple into the preamplifier output. For that reason I also took data at preamp output at 1.1VRMS. This is the voltage just before the internal power amp clips.
Even for the case that the MRX is being used with its internal power amp I still needed to make measurements at preamp output. If I made all the measurements at the internal power amp output the distortion and noise of the internal power amp would prevent you from seeing the performance of the front end. We do this for all AVRs with preamp outputs.
All numbers in this review are for the worst-case channel but channel matching of the MRX 510 was close.
The IC DAC performance dominates most of the MRX 510s performance from the digital inputs. We used HDMI at 192k samples/sec and a 24 bit depth. The test was done with the preamp output level set to produce 2VRMS for a 0dBFS signal in. At that setting the SNR was 102.8dB flat 20Hz – 20kHz and the A weighted SNR was 105.6dB. Since the IC DAC noise is the dominate noise source in the signal chain reducing the volume to produce 1.1VRMS at 0dBFS at the preamp outputs changed the SNR only slightly. The SNR at 1.1 VRMS preamp out was 101.4dB flat 20Hz – 20kHz and 104.5dB A weighted. That small decrease is from analog noise after the volume control.
The line linearity test below shows if the analog output changes linearly with a change in the digital input word. The straight line is maintained until the IC DACs noise starts to dominate. At that point the line goes up since the digital word is changing but the analog output, composed of noise, remains the same. Non-linear transfer characteristics of the DAC could cause the curve to go negative or take a discrete jump.
The 3dB deviation point from the 2VRMS full scale level is 104dB. This correlates to the SNR flat from 20Hz to 20kHz.
Shown below is the time domain plot of a sine wave at -90dBFS (15th bit is the first to toggle) which is dominated by the noise that is approximately at the 17 bit equivalent level. This graph is with 0dBFS at 2VRMS (24 bit, 192kHz data).
The sinusoidal shape indicates the linearity of the DAC is good. We can also see the linearity in the frequency domain with a dithered test signal of -60dBFS. This graph is with 0dBFS at 2VRMS from the preamp outputs.
Note the rise in the noise floor at 24 kHz. This is the noise shaping of the Delta Sigma DAC. Noise in a Delta Sigma DAC is pushed outside the audio band to an area above audibility. It is rare to see the shaping start at a low 24kHz. This is a property of the Cirrus Logic CS42528 IC DAC used in this product. We saw the same thing in the Arcam AVR750 which used the same IC DAC. If you look at other LPCM spectra published here, you will not see this. It is not audible. The in-band noise floor is flat with a small 5th harmonic visible. The 22kHz spur appears to be signal independent also showing up in the -90dB spectra (no shown). Note the AC line spurs to the left of 1kHz are low at this signal level.
Reducing the level of the preamp output to 1.1VRMS full scale yielded the distortion curve below from 20Hz to 20kHz
The bump at 2kHz is also from the Cirrus Logic CS42528 IC DAC. It was also seen in the ARCAM AV750. Despite these performance glitches this part is popular because it has 8 channels in one package as well as a 2 channel ADC. It also has the SPDIF 2 channel receiver. None of these performance quirks is called out in the spec sheet. The rated SNR of the IC DAC in the spec sheet is optimistic which is rare for an IC DAC.
Increasing the output level to 2VRMS demonstrates the feed-through of the internal power amp harmonics at clipping. The bump from the IC DAC almost disappears as the internal power amp feed-through dominates. The Renesas R2A152XXFP LSI AVR chip at 2VRMS is also contributing part of the THD. That part shows a marked increase in distortion above 1.1VRMS.
Depending on the design of the external power amp you chose it might have more distortion than what appears at the MRX 510s preamp output in the curve above and thus dominate the total system performance.
To repeat, this THD curve only applies if an external power amp that can deliver 200 Watts average into 8 Ohms with a gain of is 20V/V is attached to the MRX510. In all other cases the THD curve shown just above this, at a level of 1.1VRMS at the preamp output represents the performance of the unit.
The spectra shown below are for the 1.1VRMS VRMS preamp output at 0dBFS. The internal power amp is not clipping but close to full scale and we see small power supply related spurs in the -125dB to -130dB range out to several kHz.
The THD at 1kHz measured 0.0035% and THD+N at 1kHz was only a fraction higher at 0.0036% demonstrating the low noise floor. Note the noise floor has changed from the -60dBFS spectra above. The -60dBFS spectra went out to 40kHz and the FFT bandwidth per bin thus each been holds more noise. It is a measurement artifact. This is why a keep pointing out that the noise floor of the FFTs should not be used as a proxy for SNR.
Note the FM modulation around the 1kHz spur occurs over a small bandwidth. This is an HDMI related clock issue. We see it on all AVRs even the ESS based products which have internal ASRC converters. Only the Bryston SP-3 was free of this. That unit used an external ASRC. We have seen much wider spreading of the side bands than this as well as higher amplitudes in some products. Without an ASRC, which is the case of the MRX 510, it appears the difference in the HDMI clock characteristics is dependent on the HDMI receiver IC chip selected.
Below is the same spectra form 0Hz to 1kHz. The sidebands around 1kHz are more clearly seen. The maximum level is -98dB and it is confined between 900Hz and 1.1kHz.
AC line spurs extended beyond 3kHz but the largest is 120Hz at -108dB. Like the graph just above this 0dBFS is 1.1VRMS at the preamp outputs.
The frequency response with HDMI in to the unit is shown below. The unit was -3dB down at 50kHz with an input sampling rate of 192k samples/sec.
Crosstalk was capacitive coupling at -88dB at 1kHz and -68dB at 10kHz.
Direct Analog Performance
The plot of THD vs. frequency is impressive at 1.1VRMS at the preamp output with the volume set at unity gain as shown below.
At the 1.1VRMS the Renesas R2A152XXFP LSI AVR chip is performing well.
Below I show the THD vs. frequency at 2VRMS preamp output at unity gain. The Renesas R2A152XXFP produces more distortion at 2.0VRMS at its output pin with the internal stereo input selector switch in place compared to when the R2A152XXFP is in DAC mode. Some of the distortion shown below is from the internal power amp clipping feed-through to the preamp outputs especially above 5kHz. This feed-through distortion appears to come on sharply above 1.5VRMS.
Again the graph above only applies is the unit is used as a Pre/Pro when a large external power amp attached.
With the preamp output reference level at 1.1VRMS the SNR is 105.5dB flat from 20Hz -20kHz and 110.5dB A weighted.
The noise from the Renesas LSI AVR R2A152XXFP IC stays constant as we increased the analog input level from 1.1VRMS to 2.0VRMS but kept the volume control at the same spot (unity gain). The preamp output reference voltage increases and the SNR follows the change.
At 2VRMS from the preamp the expected 5dB (2VRMS/ 1.1VRMS) change was observed. The SNR is 110.2dB flat 20Hz to 20kHz and 115.7dB A weighted. The internal power amp clipping does not enter into the SNR since it is taken with the input grounded.
The 115.7dB figure at 2VRMS is competitive with some analog preamps as is the 0.0015% THD at 1kHz at 1.1VRMS. You cannot have both with the same setup although as long as your external power amp with THX gain is running below 120 Watts average you will be in the low distortion zone.
For the 1kHz spectra below we return to the 1.1VRMS preamp output with the volume at unity gain.
Not the 1kHz FM modulation tones we saw in the HDMI digital test is gone here. The noise of the analog channel is much lower since the IC DAC was the dominate noise source for the HDMI test. In this plot the FFT noise per bin is down since the SNR is higher. As a result more AC line spurs are exposed but if you compare the HDMI 1kHz FFT you will see all visible line spurs are at the same level.
The 0Hz to 1kHz spectra below shows the AC line spurs below 1kHz are also at the same level as the HDMI spectra under the same conditions.
In direct analog the frequency response is very flat. It is down only -0.4dB at 90kHz as is shown below.
Crosstalk was capacitive coupling at -92dB at 1kHz and -72dB at 10kHz.
Performance with the ADC in the System
To get access to ARC with analog inputs you need to put the ADC (Analog-to-Digital Converter) in the signal path. Distortion is still very low with a full scale at 1.1VRMS RCA analog input (I am highlighting this to distinguish from the preamp output level I used above which has the same value). 1.1VRMS is more typical of the maximum from a phono preamp or other analog tape media. The graph of THD vs. frequency with the ADC in the loop is below.
Note the bump at 3kHz is again from the Cirrus Logic CS42528 IC DAC.
The analog input level that takes the ADC above full scale is above 2.5VRMS which is the maximum level we used in these tests. Anthem reports the value is 3.3VRMS
Since we were below the ADCs full scale at a 1.1VRMS analog input we measured an SNR of at 92dB 20Hz – 20kHz flat and 95.5dB A weighted. This noise penalty is a result of not toggling all the bits in the ADC since we did not want to get near ADC clipping. If we adjusted the gain of the analog input to just below clipping the SNR numbers would improve but in practice doing this could risk clipping the ADC with a music signal. 95.5 dB is an order of magnitude more than the SNR of phono or analog tape so this number is higher than required.
The sampling rate with ARC on can be seen to be 48k samples/sec in the frequency response plot below which cuts off sharply at 22kHz.
Tape Monitor and 2nd Room
The 2nd room has an additional IC DAC so optical and coax inputs appear at the room 2 output. HDMI does not appear on room 2. Unique to the Anthem AVR and Pre/Pros is the ability to mute the tape input with an on screen GUI. This allows the room 2 to be used as a tape monitor without oscillation. I will have a short technical brief on this issue on the website later since it is becoming increasingly rare to find a tape monitor function even on 2 channel units. Yet another reason to consider the MRXs for two channel deployment.
Internal Power Amplifier
The internal power amplifier performs well. For most setups this is all you need and an external power amp is not required.
Frequency response 20Hz – 20kHz was ±0.017 dB. SNR differed by 6dB between channels for reasons that are not clear. The internal power amp put out 140 Watts average into 8 Ohms with both channels drive with a THD of 0.012%. The SNR referenced to that power level using the noise level measured at 1 Watt average was 106.7dB in the worst channel flat 20Hz – 20kHz. That is better than the Cirrus Logic CS42528 IC DAC, which is just what we want.
The THD at 100 Watts average into 8 Ohms is shown below.
THD is 0.008%. AC line spurs go out to 5kHz but they are very low above 1.1kHz. The AC line spur level is better seen in the plot between 0Hz to 1kHz below.
The 120Hz spur was -95dB and the spur 240Hz is -98dB. Modulation spurs at 880Hz and 1120Hz (120Hz space from 1kHz) were at -105dB.
At 100 Watts average into 8 Ohms the 19kHz / 20kHz IM for the 2nd and 3rd intermodulation products was 0.021% combined. The 1kHz 2nd order IM was a very low at -102dB. The 3rd order product was also low at -79dB at 19kHz and 21kHz.
A plot of THD vs. Power for 2 channel load at 8 Ohms is below. Only one channel shown. Anthem is clearly being very conservative in its specifications for the MRX 510.
Note the very low distortion level below clipping. Also note this plot is composed of 21 points. The next to last point is at 150 watts and then the last point is the 1% THD. How the distortion changes between 150 Watts and the 1% point cannot be inferred from the straight line.
The THD vs. average power into 4 Ohms with both channels driven is shown below. Note the very low distortion levels to the edge of clipping. Again note the graph is granular and the next to last point is 190 Watts. The trajectory to 2% distortion is not the straight line shown.
The MRX 510 offers good performance before ARC is considered. The limitation, as is the case with most AVRs at or below this price point, is the IC DAC SNR. The unit has the ability drive an external power amplifier without muting. The preamp outputs can exceed 2VRMS.
Conclusions about the Anthem MRX 510 7.1 A/V Receiver
I usually find receiver reviews hard to do because they now have so many features to touch on. From streaming services to mp3 enhancement, 11 channels of audio or support for 4 zones of audio, I feel like I can never fully explore everything they offer. The Anthem MRX 510 review is easier because Anthem puts all of the focus on the audio performance of the receiver.
Anthem Room Correction does a remarkable job with all my speaker systems. It integrates monitors and a subwoofer, or drives full range speakers with equal aplomb. It adds an extra level of detail where other room correction systems introduce a bit of haziness. I never use room correction(other than Anthem Room Correction) for music listening, and I use Anthem Room Correction with everything. Unless you fall into that minority of people that custom-built a listening room to be acoustically perfect, ARC will improve your listening experience.
Everything in the MRX 510 is well designed and executed. The setup and menu system are easy to navigate, using ARC is quick and painless, and the amplifier never ran out of power when I pushed it. People look for different things in a receiver. If what you are looking for is sound quality then you should look at the MRX 510 as Anthem has put that front and center.