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Monolith HTP-1 AV Processor Measurements (June 2023 Firmware + User Testing)

GXAlan

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Monolith HTP-1 AV Processor
(User Measurements; August 2023)
The Monolith HTP-1 was released over 3 years ago. Since its release, the HTP-1 has held steady at $4000, which means there's actually been a nearly 20% discount factoring inflation. There have been rumors that the HTP-1 will see a price increase shortly due to a combination of both increasing costs in the supply chain and inflation. What isn't a rumor is how hard it is to get one when it's in stock.

Three years ago, no one was sure how well Monoprice could support and handle a premium product like this. While there were early challenges, and there are still supply contraints, the on-going firmware support and homebrew support from end users like @anomaly has made the HTP-1 a compelling and competitive product even in the present day.

This is an update to @amirm's review from 2020 reflecting 3 years of firmware updates as well as a more contemporary understanding of AVR/AVP performance and the post-Covid, post-AKM factory fire world where performance regression has been seen across other AV products.

I'll first show my best-case scenario measurements:

104.8 dB 1 kHz SINAD at 1.8V (HDMI)
(102.8 dB for AES/EBU)
1692748485017.png
1692748333767.png


Update: I got 104.97 dB at 1.9V with a 2.2V nominal
1692813633408.png



Software and Hardware versions:
system software: V1.10.0
guiNodeRed: commit 3071dcc Date: Mon Jun 5 23:31:49 2023 -0400
avController: 4.89 Built Aug 3 2021, 14:46:17
APM Module: 258: APM 119 v258, May 20 2023
HDMI Module: 73.50.34
backplane firmware: 51
hardware: Backplane HW: 3. MIO HW: 2 DAC HW: 3
Serial Number: XXX
rootfs ver: rootfs-20191215.xz


HTP-1 Configuration:
Direct, L and R channels only
PCM bias enabled for signal detection
LCD display off

Digital Signal Generators
HP Omen 15 laptop/NVIDIA RTX2060M HDMI on AC power --> HDMI1 of the Monolith HTP-1
HP Omen 15 laptop on AC power --> USB Yellowtec PUC2 Lite --> AES/EBU of the Monolith HTP-1

ADC
E1DA Cosmos ADC, Grade A. The E1DA dBFS to voltage was calibrated with a Kaiweets HT118E 20,000 count multimeter. 10V was selected for the highest input impedance.

Analysis Software Configuration
Multitone Analyzer 1.0.87 from @pkane
20Hz-20kHz bandwidth* (@amirm 's APx555 dashboard is stricter)
2 second warm-up time for each measurement

My best measurement was at 1.8V at 104.8 db THD+N is just 1 dB shy of Monoprice's official specification of 106 dB SINAD. This may be due to electrical noise in my own home as well as limitations of my laptop's HDMI output relativeto a high-performance signal generator.
1692770847808.png

1692770866793.png


To achieve this, I set the maximum output to 1.8V in the internal configuration and then fed it a 0 dBFS test tone from @pkane 's Multitone tool. For an amplifier with 23.1 dB of gain on its XLR inputs like my Yamaha MX-A5000, 1.8V on the balanced input gives you 25.72V out, or 165W into 4 ohms.

Two questions have been asked since the original 2020 review:

1) The HTP-1 actually seems to do well at lower voltages. How does the SINAD look vs. lower output voltages?
2) Has the latest firmware/optimal configuration addressed the problem with 15-bits of linearity?

My first sweep was done with the maximum output voltage set to 3.4V. There is actually a typo on the watermark
1692760272821.png



I chose 3.4V to see how well the HTP-1 could come to the Marantz AV10 (which reaches its highest 108 dB SINAD at 3.3V at Audioholics).

As you can see in the chart above, the HTP-1 is essentially as good as the Marantz AV10 up until about 2V. At the lowest output levels that's labeled at Audioholics, we see that the Marantz AV10 at 95.3mV had an 82 dB SINAD (Audioholics APx585)The HTP-1 with my homebrew test setup already reached 82 dB SINAD as a lower voltage of 86.0mV and at the same 95.3 mV, it beat the AV10, reaching 83 dB SINAD.

At very low levels, the Monolith HTP-1 has a higher SINAD than even the Marantz AV10!

95 mV seems really low when we're typically focused on 2V and 4V SINAD for DACs, but 95 mV with the HypeX NC502MP powered Monolith 8250X with 25.7 dB gain = 1.83V to the speakers. With a Revel F228Be pair that's ~2-4 feet from the wall, that's already about 82.6 dB at 10 feet.

1692755245691.png


You can actually see that the HTP-1 breaks the 100 dB SINAD threshold as low as 0.75V and it stays above 100 dB all the way to 3.4V! If we think about it in the context of pairing this processor with an amplifier we can see that there's a very nice range of output power to the speakers with different gains.

Monolith M8250X (Hypex NC502MP) - 25.7 dB gain
0.75V + 25.7 dB = 14.45V
3.4V + 25.7 dB = 65.5 V
So into 4 ohms, 52W to clipping

Benchmark AHB2 - 9.2 db gain mode
0.75V + 9.2 dB = 2.16V
3.4V + 9.2 dB = 9.81V
So into 4 ohms, 1.2W to 24W

Benchmark AHB2 - 17 db gain mode
0.75V + 17 dB = 5.31V
3.4V + 17 dB = 24.1V
So into 4 ohms, 7W to 145W


Testing at different maximum output voltages
The maximum output voltage setting in the configuration presumably reflects changing the analog volume IC. Although it the HTP-1 web configurator allows you to enter a value of 7V, the 0 dBFS digital signal produces 4.1V at the XLR outputs, which is consistent with the current revision of the user manual.

Apologies. The graph scaling isn’t stable.
I was trying to get this post out as fast as I was able.
A most confounding, so peculiar oversight.
I will run more detailed sweeps tomorrow to make it right.



1692761891845.png




1692764350643.png


1692764676194.png



You can see how the interplay between the DAC's volume (set by the dBFS of the test one) relative to the maximum output voltage interacts.

I did not read the manual before running these measurements, but it only after writing up this post that I saw this nugget in the user's manual:

1692771875594.png


I will do a full set of measurements with the maximum output level near 2.2V. That might get me into the 106 dB SINAD range at 1.8V, but you can still get a general sense of performance from the above sweeps.


Linearity
All E1DA Cosmos ADC's have a DC problem which affects the automated linearity sweep. However, in Amir's original review at 4V output, he saw the unit muting below -90 dB. It was unclear if this was a firmware bug, a slow PCM-detection bug, or some combination.

At least as I have the unit configured, with the 2023 firmware, it works fine. For these tests, I set the E1DA Cosmos for a 4V input.

Here, we see that when the HTP-1 outputs 4.06V, it is 2.1dBFS for the E1DA Cosmos ADC.

1692765123354.png


Feeding it -100 dBFS, the 1 kHz spike measures -102.07 dBFS
1692765225242.png


And feeding it a -110 dBFS test tone or -120 dBFS test tone, we can see that it doesn't auto-mute.
1692765283920.png

1692765316296.png


In short, the auto-muting bug which led the HTP-1 to have a headless panther is not an issue with my test. And again, the rise below 1 Hz is the fault of the E1DA Cosmos ADC not the AVP.

Discussion
For me, personally, there are two ways I look at AVR/AVP measurements. Comparing the 2V/4V unbalanced vs. balanced out from an AVR/AVP is important to show how big the gap is between a dedicated 2-ch DAC and a multi-purpose product. With high DAC output voltages, you can use lower gain amplifiers downstream which can also theoretically improve end-to-end SINAD. Remember, even if ultra-premium SINAD is not audible, for 2 channel audio, it's pretty affordable to hit the extremes of mathematical transparency where your choices for gear can focus on aesthetics, ergonomics, and reliability/customer service. Having a wish list for more performance with no added cost is free, so why not ask manufacturers to try their hardest?

On the other hand, I don't buy a new amplifier every year. Or rather, I don't buy a new multi-channel amplifier for my home theater every year. I have the amplifiers with the gain structure that they have. The other way to look at AVR/AVP measurements is to think about what sort of voltages you need to hit +0 dB THX reference levels, with 85 dB averages and 105 dB peaks. At my age, I routinely listen below reference level. For me, my AVP is my last component in the signal chain before the amplifier and I prefer multichannel amplifiers with a lot of channels in one box paired with efficient speakers rather than dealing with multiple amplifiers or multiple active speakers and relying on a hub-and-spoke model of 12V trigger cables.

For me, what's most important is not the SINAD at 0 dBFS, but the SINAD that I get at the 70-85 dB SPL range at my listening position and the voltages that are required. For me, I never am at 4V.


Conclusion
The Monolith HTP-1 remains a low-volume product with inconsistent supply. Maybe you have to think of it like a Rolex Daytona or Hermes Kelly handbag and instead of winning the Mega Millions or PowerBall lottery, you just have to win the "in-stock" lottery which is a lot easier.

If you want an advanced 16-channel AV processor, your options are pretty limited. The popular choices have been the Harman products (Arcam, JBL Synthesis), StormAudio, Trinnov, and Marantz. If you want an advanced 16+ channel AV processor that's "Made in the USA" from domestic/foreign components, the HTP-1 stands ahead of its peers.

These 1 kHz SINAD measurements, taken on a homebrew E1DA Cosmos ADC show that the HTP-1 is certainly on the podium in the Olympics of AV processors if not the very best in rooms/speakers/amps that don't require high output voltages. At its price point, it's neck-and-neck with the reported measurements of the $7000 Marantz AV10 when using amplifiers with moderate to high gain. If you take advantage of the HTP-1's PEQ (which can be applied in combination with Dirac) and the HTP-1's Loudness Contour capabilities that are missing from the Marantz, you have to get into the realm of StormAudio and Trinnov, both of which have much worse SINAD at lower voltages and are $10,000+ extra. The power of PEQ is to equalizer your speakers using high-resolution data from the Klippel NFS above the transition frequency and then using Dirac and your in-home calibrated microphone to focus all of its correction in the bass.

Just a week ago, I mentioned to @jhaider that if I won a raffle and could pick between the $7000 Marantz AV10 and the $4000 Monolith HTP-1, I think I'd go for the Marantz for the more traditional feature set, ergonomics, and looks. I'm a big fan of Marantz when it's in the champagne color. I've owned multiple generations of their integrated amps and currently use the Marantz SA-10 and Marantz PM-10 Reference line in my 2-channel setup. Now, having bought the HTP-1 and spending just a few hours with it, I see why the HTP-1 has such a loyal following.

Ken Ishiwata was not an engineer but an ambassador for Marantz to help define its identity and goals. Monoprice and its Monolith brand has Hobie Sechrest (@MonolithGuy ) as its brand ambassador and product/program manager. I'm pretty sure Hobie's name will be held in the same esteem if Monoprice continues to produce world-class products like this.

Hobie, don't let us down when it comes to Dirac ART on the HTP-1 and when Dirac ART finally is released, please send a review unit to Amir to re-test.
 
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Thanks for the in depth testing! I fully agree with you on AVR performance at the 75db "reference" level listening as being most important for this processor. Good to see positive results as I picked one of these units up a few months ago.
 
104.98 dB
1 kHz SINAD at 1.9V
10Hz to 22.4 kHz bandwidth
96 kHz sampling rate
HTP-1 set for 2.2V maximum output level
1692813658451.png

HDMI, 2.2V peak, 10Hz to 22.4 kHz bandwidth

At maximum output level of 2.2V nominal, I was able to get 104.53 dB at 1.448V which increased to 104.98 dB at 1.9V and ultimately finishing at 104.9 dB at 2.3V.

I believe 104 dB was the highest SINAD recorded here by @amirm with the AVR-X8500H with the original AKM DAC at 1.45V. To be fair, the Denon did that with unbalanced output as compared to the HTP-1 with balanced output.

@amirm, this is a record breaker for a 16-channel processor for highest SINAD at any level using a plain laptop HDMI output (with the laptop even plugged into AC power).

At the relaxed standard of 20Hz to 20 kHz bandwidth, trying to break the 105 dB barrier, I was able to get this:

1692816110392.png


So again, the HTP-1 has the highest measured performance of any 16-channel processor measured here to date. The Marantz AV10 should have higher SINAD, but no one has sent one in yet.

The HTP-1 is a bargain if you need its features and have an amplifier with sufficient gain.
 
Thank you for correctly evaluating the HTP-1!
Thanks! It was a bit of a gamble especially since Dirac doesn’t like upfiring Atmos speakers, but it ended up being a nice performer! Using PEQ/Dirac simplifies my Bose 901 integration into the home theater.

To be clear, my review is no more correct than Amir’s. Except for the firmware/config issue of the linearity that affected the original model 3 years ago.

I think prior to these fancy 16 channel processors, AVR firmware was pretty reliable. Even the previous gen Yamaha and Arcam’s were stable but suddenly became extremely buggy when the current generation was released.

I still agree with Amir that I’d like to see AVP’s do great from 1mV to 10V, or at least do great all the way to 4V.

The only thing that’s different is that with the ability to cheat 3 years into the future, the HTP-1 has shown to have idiosyncratic strengths (works better with high gain amps rather than low gain amps) and Monoprice’s uncertain customer service and software support has proven to be amazing. Again, not something that was easily forecasted.

3 years ago, the Emotiva line and HTP-1 were probably considered equally buggy and you would have assumed that Emotiva, with more product history, would have been ahead three years later. Turns out that the HTP-1 has been more reliable even though there was a recent glitch that prevented a batch of HTP-1’s not to work with Dirac, but Monoprice stepped up.

If they drop the ball on Dirac ART, they will have burned up their momentum and goodwill. If Dirac ART comes out on time, the HTP-1 will be like the original Lexus LS400 and move Toyota from the masses to the luxury market.
 
Thanks! It was a bit of a gamble especially since Dirac doesn’t like upfiring Atmos speakers, but it ended up being a nice performer! Using PEQ/Dirac simplifies my Bose 901 integration into the home theater.

To be clear, my review is no more correct than Amir’s. Except for the firmware/config issue of the linearity that affected the original model 3 years ago.

I think prior to these fancy 16 channel processors, AVR firmware was pretty reliable. Even the previous gen Yamaha and Arcam’s were stable but suddenly became extremely buggy when the current generation was released.

I still agree with Amir that I’d like to see AVP’s do great from 1mV to 10V, or at least do great all the way to 4V.

The only thing that’s different is that with the ability to cheat 3 years into the future, the HTP-1 has shown to have idiosyncratic strengths (works better with high gain amps rather than low gain amps) and Monoprice’s uncertain customer service and software support has proven to be amazing. Again, not something that was easily forecasted.

3 years ago, the Emotiva line and HTP-1 were probably considered equally buggy and you would have assumed that Emotiva, with more product history, would have been ahead three years later. Turns out that the HTP-1 has been more reliable even though there was a recent glitch that prevented a batch of HTP-1’s not to work with Dirac, but Monoprice stepped up.

If they drop the ball on Dirac ART, they will have burned up their momentum and goodwill. If Dirac ART comes out on time, the HTP-1 will be like the original Lexus LS400 and move Toyota from the masses to the luxury market.
Great addition! Thanks for this! And thank you to Amir for promoting it!

Makes my decision for going with the Marantz AV 10/AMP 10 that much more difficult. As far as "bargain" or "budget" I'd say only comparatively. These are price-point targeted products but from what I understand, made by ATI. So at nearly $10K if you pair the HTP-1 with a couple M8250xs, I'm hesitant to say "budget". ATI makes a LOT of OEM equipment for companies and amps for some of the most premium of home theater manufacturers (looking at you Trinnov) with a warranty being one of the best around, so I am skeptical of calling this Monoprice combo "budget" anything. (Looks maybe... But, how many of us showcase our AV rack? How many Trinnov owners are plopping that thing down on their WestElm credenzas?)

My $.02 anyway.

Thanks again and great review!
 
Thanks! It was a bit of a gamble especially since Dirac doesn’t like upfiring Atmos speakers, but it ended up being a nice performer! Using PEQ/Dirac simplifies my Bose 901 integration into the home theater.

To be clear, my review is no more correct than Amir’s. Except for the firmware/config issue of the linearity that affected the original model 3 years ago.

I think prior to these fancy 16 channel processors, AVR firmware was pretty reliable. Even the previous gen Yamaha and Arcam’s were stable but suddenly became extremely buggy when the current generation was released.

I still agree with Amir that I’d like to see AVP’s do great from 1mV to 10V, or at least do great all the way to 4V.

The only thing that’s different is that with the ability to cheat 3 years into the future, the HTP-1 has shown to have idiosyncratic strengths (works better with high gain amps rather than low gain amps) and Monoprice’s uncertain customer service and software support has proven to be amazing. Again, not something that was easily forecasted.

3 years ago, the Emotiva line and HTP-1 were probably considered equally buggy and you would have assumed that Emotiva, with more product history, would have been ahead three years later. Turns out that the HTP-1 has been more reliable even though there was a recent glitch that prevented a batch of HTP-1’s not to work with Dirac, but Monoprice stepped up.

If they drop the ball on Dirac ART, they will have burned up their momentum and goodwill. If Dirac ART comes out on time, the HTP-1 will be like the original Lexus LS400 and move Toyota from the masses to the luxury market.
Since you mentioned Amir's, do you think the FW updates might have improved the following's? I don't think it is bad in terms of perceived sound quality, but I also think it would be much worse than the AV10's in terms of measurements such the same conditions but I don't know for sure, not without comparing measurements under the same conditions. Amir seemed to think power supply was the issue, if that's the case then FW probably wouldn't have fixed the issues?

index.php
 
I hope Monoprice will sell their products in Europe someday…
 
You can order it from USA, there are many European HTP-1 users. HTP-1 is multivoltage ready, 100-240V.
I don't really want to import a $4K AVP and deal with customs and possibly warranty issues if something happens.

The only reason I consider this unit is future support for Dirac ART. I only hope that either monoprice will start selling in the EU again or Denon/ Marantz models will get ART support as well.
 
I also think it would be much worse than the AV10's in terms of measurements such the same conditions but I don't know for sure, not without comparing measurements under the same conditions. Amir seemed to think power supply was the issue, if that's the case then FW probably wouldn't have fixed the issues?

I'd like to see Amir's testing of the AV10 for consistency. For the Audioholics test conditions to get “108 dB” SINAD (20-20kHz), my sweep suggests that the HTP-1's 1 kHz SINAD is better until about 2V or so at which point it falls behind as the AV10 is able to drive the voltage up. I don't think Audioholics did a THD+N relative to frequency comparison.

1) For 1 kHz, the HTP-1 seems to do better with HDMI than AES/EBU. Not what I would have expected. Could be weird interference/electrical weather at my home. Haven't had the time to test if AES/EBU is better as a sweep

2) Amir tests to 90 kHz bandwidth for the THD+N vs frequency which is "tougher" than I think what a REW sweep does.

Scenario 1:
HTP-1 set at 2.2V maximum output level; 24/96
E1DA set for 32/48
Multitone with AES17 notch, 10-22.5 kHz
1692901235296.png



Scenario 2:
HTP-1 set at 2.2V maximum output level; 24/96
E1DA set for 32/192
Multitone with AES17 notch, 10-90 kHz
1692901851874.png



Scenario 3:
HTP-1 set at 4V maximum output level; 24/96
E1DA set for 32/192
Multitone with AES17 notch, 10-90 kHz
1692902451420.png


Scenario 5
REW sweep which looks at distortion not noise

1692902744551.png


1692902770946.png
 
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Monolith HTP-1 AV Processor
(User Measurements; August 2023)
The Monolith HTP-1 was released over 3 years ago. Since its release, the HTP-1 has held steady at $4000, which means there's actually been a nearly 20% discount factoring inflation. There have been rumors that the HTP-1 will see a price increase shortly due to a combination of both increasing costs in the supply chain and inflation. What isn't a rumor is how hard it is to get one when it's in stock.

Three years ago, no one was sure how well Monoprice could support and handle a premium product like this. While there were early challenges, and there are still supply contraints, the on-going firmware support and homebrew support from end users like @anomaly has made the HTP-1 a compelling and competitive product even in the present day.

This is an update to @amirm's review from 2020 reflecting 3 years of firmware updates as well as a more contemporary understanding of AVR/AVP performance and the post-Covid, post-AKM factory fire world where performance regression has been seen across other AV products.

I'll first show my best-case scenario measurements:

104.8 dB 1 kHz SINAD at 1.8V (HDMI)
(102.8 dB for AES/EBU)
View attachment 307325View attachment 307324

Update: I got 104.97 dB at 1.9V with a 2.2V nominal
View attachment 307481


Software and Hardware versions:
system software: V1.10.0
guiNodeRed: commit 3071dcc Date: Mon Jun 5 23:31:49 2023 -0400
avController: 4.89 Built Aug 3 2021, 14:46:17
APM Module: 258: APM 119 v258, May 20 2023
HDMI Module: 73.50.34
backplane firmware: 51
hardware: Backplane HW: 3. MIO HW: 2 DAC HW: 3
Serial Number: XXX
rootfs ver: rootfs-20191215.xz


HTP-1 Configuration:
Direct, L and R channels only
PCM bias enabled for signal detection
LCD display off

Digital Signal Generators
HP Omen 15 laptop/NVIDIA RTX2060M HDMI on AC power --> HDMI1 of the Monolith HTP-1
HP Omen 15 laptop on AC power --> USB Yellowtec PUC2 Lite --> AES/EBU of the Monolith HTP-1

ADC
E1DA Cosmos ADC, Grade A. The E1DA dBFS to voltage was calibrated with a Kaiweets HT118E 20,000 count multimeter. 10V was selected for the highest input impedance.

Analysis Software Configuration
Multitone Analyzer 1.0.87 from @pkane
20Hz-20kHz bandwidth* (@amirm 's APx555 dashboard is stricter)
2 second warm-up time for each measurement

My best measurement was at 1.8V at 104.8 db THD+N is just 1 dB shy of Monoprice's official specification of 106 dB SINAD. This may be due to electrical noise in my own home as well as limitations of my laptop's HDMI output relativeto a high-performance signal generator.
View attachment 307384
View attachment 307385

To achieve this, I set the maximum output to 1.8V in the internal configuration and then fed it a 0 dBFS test tone from @pkane 's Multitone tool. For an amplifier with 23.1 dB of gain on its XLR inputs like my Yamaha MX-A5000, 1.8V on the balanced input gives you 25.72V out, or 165W into 4 ohms.

Two questions have been asked since the original 2020 review:

1) The HTP-1 actually seems to do well at lower voltages. How does the SINAD look vs. lower output voltages?
2) Has the latest firmware/optimal configuration addressed the problem with 15-bits of linearity?

My first sweep was done with the maximum output voltage set to 3.4V. There is actually a typo on the watermark
View attachment 307358


I chose 3.4V to see how well the HTP-1 could come to the Marantz AV10 (which reaches its highest 108 dB SINAD at 3.3V at Audioholics).

As you can see in the chart above, the HTP-1 is essentially as good as the Marantz AV10 up until about 2V. At the lowest output levels that's labeled at Audioholics, we see that the Marantz AV10 at 95.3mV had an 82 dB SINAD (Audioholics APx585)The HTP-1 with my homebrew test setup already reached 82 dB SINAD as a lower voltage of 86.0mV and at the same 95.3 mV, it beat the AV10, reaching 83 dB SINAD.

At very low levels, the Monolith HTP-1 has a higher SINAD than even the Marantz AV10!

95 mV seems really low when we're typically focused on 2V and 4V SINAD for DACs, but 95 mV with the HypeX NC502MP powered Monolith 8250X with 25.7 dB gain = 1.83V to the speakers. With a Revel F228Be pair that's ~2-4 feet from the wall, that's already about 82.6 dB at 10 feet.

View attachment 307354

You can actually see that the HTP-1 breaks the 100 dB SINAD threshold as low as 0.75V and it stays above 100 dB all the way to 3.4V! If we think about it in the context of pairing this processor with an amplifier we can see that there's a very nice range of output power to the speakers with different gains.

Monolith M8250X (Hypex NC502MP) - 25.7 dB gain
0.75V + 25.7 dB = 14.45V
3.4V + 25.7 dB = 65.5 V
So into 4 ohms, 52W to clipping

Benchmark AHB2 - 9.2 db gain mode
0.75V + 9.2 dB = 2.16V
3.4V + 9.2 dB = 9.81V
So into 4 ohms, 1.2W to 24W

Benchmark AHB2 - 17 db gain mode
0.75V + 17 dB = 5.31V
3.4V + 17 dB = 24.1V
So into 4 ohms, 7W to 145W


Testing at different maximum output voltages
The maximum output voltage setting in the configuration presumably reflects changing the analog volume IC. Although it the HTP-1 web configurator allows you to enter a value of 7V, the 0 dBFS digital signal produces 4.1V at the XLR outputs, which is consistent with the current revision of the user manual.

Apologies. The graph scaling isn’t stable.
I was trying to get this post out as fast as I was able.
A most confounding, so peculiar oversight.
I will run more detailed sweeps tomorrow to make it right.



View attachment 307359



View attachment 307368

View attachment 307369


You can see how the interplay between the DAC's volume (set by the dBFS of the test one) relative to the maximum output voltage interacts.

I did not read the manual before running these measurements, but it only after writing up this post that I saw this nugget in the user's manual:

View attachment 307388

I will do a full set of measurements with the maximum output level near 2.2V. That might get me into the 106 dB SINAD range at 1.8V, but you can still get a general sense of performance from the above sweeps.


Linearity
All E1DA Cosmos ADC's have a DC problem which affects the automated linearity sweep. However, in Amir's original review at 4V output, he saw the unit muting below -90 dB. It was unclear if this was a firmware bug, a slow PCM-detection bug, or some combination.

At least as I have the unit configured, with the 2023 firmware, it works fine. For these tests, I set the E1DA Cosmos for a 4V input.

Here, we see that when the HTP-1 outputs 4.06V, it is 2.1dBFS for the E1DA Cosmos ADC.

View attachment 307370

Feeding it -100 dBFS, the 1 kHz spike measures -102.07 dBFS
View attachment 307372

And feeding it a -110 dBFS test tone or -120 dBFS test tone, we can see that it doesn't auto-mute.
View attachment 307373
View attachment 307374

In short, the auto-muting bug which led the HTP-1 to have a headless panther is not an issue with my test. And again, the rise below 1 Hz is the fault of the E1DA Cosmos ADC not the AVP.

Discussion
For me, personally, there are two ways I look at AVR/AVP measurements. Comparing the 2V/4V unbalanced vs. balanced out from an AVR/AVP is important to show how big the gap is between a dedicated 2-ch DAC and a multi-purpose product. With high DAC output voltages, you can use lower gain amplifiers downstream which can also theoretically improve end-to-end SINAD. Remember, even if ultra-premium SINAD is not audible, for 2 channel audio, it's pretty affordable to hit the extremes of mathematical transparency where your choices for gear can focus on aesthetics, ergonomics, and reliability/customer service. Having a wish list for more performance with no added cost is free, so why not ask manufacturers to try their hardest?

On the other hand, I don't buy a new amplifier every year. Or rather, I don't buy a new multi-channel amplifier for my home theater. I have the amplifiers with the gain structure that they have. The other way to look at AVR/AVP measurements is to think about what sort of voltages you need to hit +0 dB THX reference levels, with 85 dB averages and 105 dB peaks. At my age, I routinely listen below reference level. For me, my AVP is my last component in the signal chain before the amplifier and I prefer multichannel amplifiers with a lot of channels in one box paired with efficient speakers rather than dealing with multiple amplifiers or multiple active speakers and relying on a hub-and-spoke model of 12V trigger cables.

For me, what's most important is not the SINAD at 0 dBFS, but the SINAD that I get at the 70-85 dB SPL range at my listening position and the voltages that are required. For me, I never am at 4V.


Conclusion
The Monolith HTP-1 remains a low-volume product with inconsistent supply. Maybe you have to think of it like a Rolex Daytona or Hermes Kelly handbag and instead of winning the Mega Millions or PowerBall lottery, you just have to win the "in-stock" lottery which is a lot easier.

If you want an advanced 16-channel AV processor, your options are pretty limited. The popular choices have been the Harman products (Arcam, JBL Synthesis), StormAudio, Trinnov, and Marantz. If you want an advanced 16+ channel AV processor that's "Made in the USA" from domestic/foreign components, the HTP-1 stands ahead of its peers.

These 1 kHz SINAD measurements, taken on a homebrew E1DA Cosmos ADC show that the HTP-1 is certainly on the podium in the Olympics of AV processors if not the very best in rooms/speakers/amps that don't require high output voltages. At its price point, it's neck-and-neck with the reported measurements of the $7000 Marantz AV10 when using amplifiers with moderate to high gain. If you take advantage of the HTP-1's PEQ (which can be applied in combination with Dirac) and the HTP-1's Loudness Contour capabilities that are missing from the Marantz, you have to get into the realm of StormAudio and Trinnov, both of which have much worse SINAD at lower voltages and are $10,000+ extra. The power of PEQ is to equalizer your speakers using high-resolution data from the Klippel NFS above the transition frequency and then using Dirac and your in-home calibrated microphone to focus all of its correction in the bass.

Just a week ago, I mentioned to @jhaider that if I won a raffle and could pick between the $7000 Marantz AV10 and the $4000 Monolith HTP-1, I think I'd go for the Marantz for the more traditional feature set, ergonomics, and looks. I'm a big fan of Marantz when it's in the champagne color. I've owned multiple generations of their integrated amps and currently use the Marantz SA-10 and Marantz PM-10 Reference line in my 2-channel setup. Now, having bought the HTP-1 and spending just a few hours with it, I see why the HTP-1 has such a loyal following.

Ken Ishiwata was not an engineer but an ambassador for Marantz to help define its identity and goals. Monoprice and its Monolith brand has Hobie Sechrest (@MonolithGuy ) as its brand ambassador and product/program manager. I'm pretty sure Hobie's name will be held in the same esteem if Monoprice continues to produce world-class products like this.

Hobie, don't let us down when it comes to Dirac ART on the HTP-1 and when Dirac ART finally is released, please send a review unit to Amir to re-test.

What a terrific review. I found your comment that, "...I have the amplifiers with the gain structure that they have. The other way to look at AVR/AVP measurements is to think about what sort of voltages you need to hit +0 dB THX reference levels, with 85 dB averages and 105 dB peaks." to be dead nuts on. The gain staging with the HTP-1 had me chasing various amps and I finally settled on some Hypex NC500OEM based amps and had the HTP-1 set to 2.9v. Funny enough, your measurements seems to indicate I was pretty close. Once dialed in, the HTP-1 was more than capable of sound very very good. I loved Dirac and DLBC and miss that with the AV10. I also liked the hokey but effective Wide Synth feature. But the major issue I had was that I needed the thing to just work and deliver on promised features like DTSX Pro. It became a project and features became more and more elusive or empty promises. I won't go into the litany of promises and claims that were largely floated out there whenever they conviently had some inventory to move. In the end, its a hobbiest platform and for those that love the technical tweaking and great community support from some very dedicated embedded programming users on AVS, then the HTP-1 might just be for you. I hope they really do deliver on the many promises as it will light a fire under Sound United to get DLBC and possibly ART out the door even faster IMO. In any event, you should do this more often! Great review. And I'm sure Amir doesn't mind guys like you helping take a load off for a few fleeting moments. :)
 
As far as "bargain" or "budget" I'd say only comparatively.

Agreed. The B stock drops you down to $3200 which is cheaper than the old flagship Denon AVR-X8500H but still more expensive than pretty much most premium AVRs.

This HTP-1 is like the 2025 Corvette ZR1 at $150K, which is 3x the price of an ordinary car and no faster at safe driving speeds, but performs like super cars that cost multiples more.

In the end, its a hobbiest platform and for those that love the technical tweaking and great community support from some very dedicated embedded programming users on AVS, then the HTP-1 might just be for you. I hope they really do deliver on the many promises as it will light a fire under Sound United to get DLBC and possibly ART out the door even faster IMO.

+1 on it being a Hobbyist platform. It’s extremely powerful but there isn’t a “wizard“ like what you get from Marantz/Denon/Sony/Yamaha. This is for ASR- and AVSForum highly-experienced hobbyists that are setting up their own home theater and not for someone setting up their very first “better than soundbar setup.”

In a way, I wouldn’t even trust a BestBuy or Amazon home theater setup person to think about gain staging, etc. But setting up a Denon AVR with a single Audyssey measurement is well within the realm of an amateur.

I think the HTP-1 would be a good creston/premium install option if they had steady availability in the way that Datasat was popular with installers.

Monoprice has cut corners to achieve a target price/profit margin.

The corners cut are
1) limited output voltage
2) limited I/O (like phono amp)
3) reliant on eARC for 8K setups
4) No on screen display for volume control
5) Budget feeling remote control
6) inconsistent availability* (Think D&M and AKM fire)

But in doing so, they put ALL of the budget toward audio features like 16 band PEQ that works in parallel with Dirac, loudness contour, and they have moved ahead of the peers in terms of things like DLBC and Dirac ART.

Right now, the only company not called StormAudio that has official industry representatives making claims that ART is coming is Monoprice. One German review site says it’s coming to the AV10 but that’s not the same.

At least here, there is rumor that the lower line products will get Dirac Art which would be great!


In another thread, I have still used the example of buying a computer for yourself versus recommending one for a friend or family member. Do you want to be lifelong tech support?

I would handily recommend the HTP-1 to enthusiasts here, but a friend looking to get the same experience on their own will be better off with Audyssey and a D&M product.
 
Agreed. The B stock drops you down to $3200 which is cheaper than the old flagship Denon AVR-X8500H but still more expensive than pretty much most premium AVRs.

This HTP-1 is like the 2025 Corvette ZR1 at $150K, which is 3x the price of an ordinary car and no faster at safe driving speeds, but performs like super cars that cost multiples more.



+1 on it being a Hobbyist platform. It’s extremely powerful but there isn’t a “wizard“ like what you get from Marantz/Denon/Sony/Yamaha. This is for ASR- and AVSForum highly-experienced hobbyists that are setting up their own home theater and not for someone setting up their very first “better than soundbar setup.”

In a way, I wouldn’t even trust a BestBuy or Amazon home theater setup person to think about gain staging, etc. But setting up a Denon AVR with a single Audyssey measurement is well within the realm of an amateur.

I think the HTP-1 would be a good creston/premium install option if they had steady availability in the way that Datasat was popular with installers.

Monoprice has cut corners to achieve a target price/profit margin.

The corners cut are
1) limited output voltage
2) limited I/O (like phono amp)
3) reliant on eARC for 8K setups
4) No on screen display for volume control
5) Budget feeling remote control
6) inconsistent availability* (Think D&M and AKM fire)

But in doing so, they put ALL of the budget toward audio features like 16 band PEQ that works in parallel with Dirac, loudness contour, and they have moved ahead of the peers in terms of things like DLBC and Dirac ART.

Right now, the only company not called StormAudio that has official industry representatives making claims that ART is coming is Monoprice. One German review site says it’s coming to the AV10 but that’s not the same.

At least here, there is rumor that the lower line products will get Dirac Art which would be great!


In another thread, I have still used the example of buying a computer for yourself versus recommending one for a friend or family member. Do you want to be lifelong tech support?

I would handily recommend the HTP-1 to enthusiasts here, but a friend looking to get the same experience on their own will be better off with Audyssey and a D&M product.

Good take. I agree. I loved SodaPink's web interface as it was a tweakers delight. It sounded flipping fantastic once I got it all dialed in. Albeit, the journey was longer than most processors I've owned to get there and the reboots (fixed by guys on AVS) was insanely annoying.

Isn't the platform designed, developed and supported by MDS much like Emotiva and several other manufacturers that use MDS? I thought it was - it was a concern of mine. But maybe they have some internal development resources now....or a few good guys on AVS. ;)

Fingers crossed we see some more manufacturers announcing and showing ART at CEDIA in a couple of weeks. I think Storm's exclusivity has ended or will before years end.
 
Isn't the platform designed, developed and supported by MDS much like Emotiva and several other manufacturers that use MDS? I thought it was - it was a concern of mine. But maybe they have some internal development resources now....or a few good guys on AVS. ;)

Fingers crossed we see some more manufacturers announcing and showing ART at CEDIA in a couple of weeks. I think Storm's exclusivity has ended or will before years end.

Hard to say. MDS is used by Emotiva, but Emotiva has some in-house resources. MDS is used by Arcam/JBL/Audiocontrol and Arcam has some in-house resources. I'm not sure if ATI was involved with the software side, or if they really want to preserve their Datasat product line.

What seems to be surprising/unexpected is that Monoprice is doing the best with feature set and Dirac so far. MDS has been in business for decades, in a high cost of living area. Maybe the secret is relying MORE on MDS rather than just trying to save money by going in-house instead of outsourcing it all.

But again, Monolith has been very enthusiastic about Dirac Art coming by the end of this year. Sound United is still saying Bass Control in 2024, potentially. So there's a chance that Monolith will have ART working before D&M have DLBC! There have been a lot of promises pre-pandemic that Monolith slipped on, and Hobie has gone on record to say that he was diagnosed with cancer, which is treatable, but certainly put the HTP-1 lower on his list of priorities, not to mention supply chain challenges ... but they really do seem to be firing on all cylinders again.
 
Hard to say. MDS is used by Emotiva, but Emotiva has some in-house resources. MDS is used by Arcam/JBL/Audiocontrol and Arcam has some in-house resources. I'm not sure if ATI was involved with the software side, or if they really want to preserve their Datasat product line.

What seems to be surprising/unexpected is that Monoprice is doing the best with feature set and Dirac so far. MDS has been in business for decades, in a high cost of living area. Maybe the secret is relying MORE on MDS rather than just trying to save money by going in-house instead of outsourcing it all.

But again, Monolith has been very enthusiastic about Dirac Art coming by the end of this year. Sound United is still saying Bass Control in 2024, potentially. So there's a chance that Monolith will have ART working before D&M have DLBC! There have been a lot of promises pre-pandemic that Monolith slipped on, and Hobie has gone on record to say that he was diagnosed with cancer, which is treatable, but certainly put the HTP-1 lower on his list of priorities, not to mention supply chain challenges ... but they really do seem to be firing on all cylinders again.
Let's hope so. Me likey more competition to drive more innovation and better products. Fun times are here again. We're certainly in a better place than we were 2 years ago in this industry - I thought AV and HiFi where dead and buried. Now we seem to be heading into another renaissance of sorts with more and more great gear. This site has had an impact as well on that front!
 
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