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Monoprice HTP-1 Home Theater Processor Review

A/V Analysis

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I'd really like to see a room measurement from the mic position after one of the room eq's are run, of a 7.1+ system to determine how much cancellation is actually going on. Ergo, how much of the original signal reaches the listener's ears. I understand that the system attempts to set the delays on each output accordingly, but there must be a significant margin for error given how many additional reflective signals are created by all of those speakers.
You'd be surprised just how accurately many systems can set speaker delays. https://www.trinnov.com/inventing-digital-acoustics/

You should look for somewhere nearby (commercial cinema or home cinema) to listen to immersive/3D audio yourself. This is a good informational video to start with:
 

Xyrium

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You'd be surprised just how accurately many systems can set speaker delays. https://www.trinnov.com/inventing-digital-acoustics/
Perhaps, but at what price? Moreover, even at some of the prices these providers are asking, when a recording is recorded in 2 ch., how is a system "faking" 5+ additional channels that don't exist in the recording? Add to this, the room reflections of all those transducers need to be factored.

Do these systems perform what I hear in a theater, which is switch to 2ch mode and play recorded music from the front, and then only when encoded for proper 5+ channel playback, engage the additional channels? If so, this would make sense, and would still mean that 5+ channel systems know better than to play 2 channel audio from 5+ channels.
 

SMG

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So this was never a truncation issue, but a gating (muting) issue, as others suggested early on.
 
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laurelkurt

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You'd be surprised just how accurately many systems can set speaker delays. https://www.trinnov.com/inventing-digital-acoustics/

You should look for somewhere nearby (commercial cinema or home cinema) to listen to immersive/3D audio yourself. This is a good informational video to start with:
In my well treated, and (basically) symmetrical room and speaker placements, Audyssey Multi-XT32 set-up measures/sets all my distances within 4-8 inches of what they actually are. My subs come up at around 2 plus feet long of what they actually are: I'm assuming because of DSP delay in the subs' circuit...I'd say that is very accurate. It also shows excellent consistency on repeated runs....Nice job you have, I'd say!
 
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A/V Analysis

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We should keep in mind that this is not a 2 channel dac.
Hopefully this unit is still in the "return window". Many thanks to the owner for arranging this review. I'm delighted that we are seeing more reviews of processors and AVRs. I know the Anthem AVR Amir tested had mediocre performance but I'm hoping the AVM60 would be better. Anthem has the ability to produce quality products (STR series) and I'm hoping (as an AVM60 owner) that their expertise extends to their processors.
I have the desire to participate here at ASR to provide measurements for surround processors and AVRs. However, I believe that a different criteria for evaluation is needed. IMO, applying Amir's DAC testing parameters does not translate well to real world performance. Most consumer amplifiers will not accept a preamp signal as high as 4Vrms.

I'm wondering if I should create a single thread for surround processor measurements or a seperate thread for each. Opinions?

SSPs I hope to have measured by Monday:
Monoprice Monolith HTP-1
Trinnov Altitude 16
Bryston SP4
Lyngdorf MP-50
Acurus Act 4
NAD M15HD (unbalanced version of M17v2, additional AM17 outputs are balanced)

SSPs I should have access to soon:
Marantz AV8805
Arcam AV40
 

A/V Analysis

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Perhaps, but at what price? Moreover, even at some of the prices these providers are asking, when a recording is recorded in 2 ch., how is a system "faking" 5+ additional channels that don't exist in the recording? Add to this, the room reflections of all those transducers need to be factored.
Reflections are factored in the same way they are for a 2 ch system (treatments, EQ, etc.). Are you familiar with Room EQ (Audyssey, Dirac, Trinnov)?

I am not a huge fan of upmixing music. I prefer to listen natively in most cases. In others, Auro3D/Auromatic is the most pleasing to my ears. I do use upmixing for 2ch broadcast TV. Much of it is down-mixed from 5.1 and properly upmixed.
See here: https://en.wikipedia.org/wiki/Matrix_decoder
Do these systems perform what I hear in a theater, which is switch to 2ch mode and play recorded music from the front, and then only when encoded for proper 5+ channel playback, engage the additional channels? If so, this would make sense, and would still mean that 5+ channel systems know better than to play 2 channel audio from 5+ channels.
Either, at the user's preference. One can choose whether or not to upmix and which upmixer to apply.
 

spacevector

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I'm wondering if I should create a single thread for surround processor measurements or a seperate thread for each. Opinions?
Definitely separate so we can bitch about them individually and keep our bitching neatly organized in threads specific to the measured product.

You should get clearance from Amir before posting I think. I have seen other members post independent measurements so it should not be an issue - doesn't hurt to ask though.
 

Francis Vaughan

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AV gear does present a whole new ball game of questions and possible metrics. Simple distortion and noise measures are fine, but we seem to accept the entire DSP chain as a magic black box. Yet the audio passes through multiple stages of processing where all manner of evils may be inflicted upon it. It may be resampled, have representation changes, truncates, redithered, and more. Yet there is no testing. All we seem to be able to achieve are tests that ignore the HT capabilities and just treat it as a glorified DAC. There must be tests possible. Reference encoded audio in the various surround formats where we might see how well the signal survives the processor. That would be of significant interest. Minimally it might shine a light on poor practices and implementations.
 

A/V Analysis

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Ok so shouldn't this change the conclusion of the review? How many volts did you get at 0dB?
3.876 Vrms
1581553678061.png
 

Tom C

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I have the desire to participate here at ASR to provide measurements for surround processors and AVRs. However, I believe that a different criteria for evaluation is needed. IMO, applying Amir's DAC testing parameters does not translate well to real world performance. Most consumer amplifiers will not accept a preamp signal as high as 4Vrms.

I'm wondering if I should create a single thread for surround processor measurements or a seperate thread for each. Opinions?

SSPs I hope to have measured by Monday:
Monoprice Monolith HTP-1
Trinnov Altitude 16
Bryston SP4
Lyngdorf MP-50
Acurus Act 4
NAD M15HD (unbalanced version of M17v2, additional AM17 outputs are balanced)

SSPs I should have access to soon:
Marantz AV8805
Arcam AV40
Separate threads. Easier to search through and focus on a particular unit.
 

audioBliss

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I can tell you that a huge issue I have seen is the crossover filters that are used in a lot AVRs are not good enough..not even close at times. Filters are not steep enough etc. And the way bass management is implemented is not correct in many cases. And now with stuff like Dirac it confuses manufacturers quite a bit it seems as to how it's all suppose to work together. A test I want to see is for example if you limit Dirac to your room transition frequency and then for some reason you want to change the level of the subwoofer. How are the filters applied? I have seen issues in other units. There are so many different combinations here where the core issue seems to be bass management and crossover filters and making it all work smoothly with Dirac or other calibration tool. I am very interested in seeing tests for that.
 
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A/V Analysis

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OK, took one step forward and possibly a few back. Here are the results:

View attachment 49940

The Biased setting does fix the low level issue. But in the process of setting up the test again, ran into the opposite problem. As you see, above 0 DB value on volume control you get some kind of compressor in action. It is not possible to get 4 volts output without going over 0 dB.

There is some talk about combination of analog and digital gain control. That may be at play here. As noted there is a setting for "Amplifier Sensitivity" but doesn't fix the problem.

I can see the same problem with the volume control barely changing the output level even though dBs count up on the display....
I believe I see where you are getting hung up Amir. You are intent on getting 4Vrms into the analyzer. It appears that the designers did not account for your desire to test exactly at 4Vrms. The Amplifier Sensitivity setting defines the clipping point of the amplifier. There does appear to be a mistake here. The Amplifier sensitivity setting allows a range of 0.1V - 7.0V. However, anything over 4.0V does nothing.

I was able to get exactly 4.0Vrms by setting the HTP-1 volume to +1dB and the AP to -0.712dBFS.
1581554506441.png


You are not seeing any sort of DSP compression, you are clipping by setting volume to +10dB. If you want to ensure you reach 4V simply set volume to +1dB and test. With a volume setting of 10dB you shouldn't exceed -10dBFS to avoid clipping.

1581557565432.png
 

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amirm

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EDIT: never mind. See the next post.

OK, back at home. I ran three separate tests to see what is going on with level compression. For all of them I set the Amplifier Sensitivity to 7 volts which is the highest it lets me set it to.

First, let's look at them as absolute level:

Monolith by Monoprice HTP-1 16-Channel Home Theater Processor Volume Compression Audio Measure...png


With volume set to 0 dB (red), there is no compression visible. Max output is now limited to 2.9 volts. Why that would be good for an amp that has 7 volts sensitivity, I don't know.

Green and Blue show what happens when you exceed 0 dB on the volume control. Clearly you get compression. We can see that more clearly if I plot the differential as linearity test normally shows:

Monolith by Monoprice HTP-1 16-Channel Home Theater Processor Volume Compression Linearity Aud...png


The red curve is not very visible but take my word for it that is flat to 0 dBFS. So no compression but again, output is limited to 2.9 volts.

We clearly see the compression and deviation in higher volume settings. It does look however like you get a bit more volume with them before compression sets it. With volume set to 6 dB, you lose linearity at 4.8 dB so you get 1.2 dB of gain. Likewise, with volume set to 10 dB, you get the same 1.2 dB of gain as compression starts at -8.8 dB.

All of these trade offs should be documented with graphs like above so people know what they are doing as they modify these parameters. I don't think I have ever measured a DAC of any kind that compresses output this way on its own.
 
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amirm

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You are not seeing any sort of DSP compression, you are clipping by setting volume to +10dB.
Ah, it is clipping. The filtering in linearity test was hiding that. That's even worse. It clips at even 1 dB on the volume!
 
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amirm

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I believe I see where you are getting hung up Amir. You are intent on getting 4Vrms into the analyzer. It appears that the designers did not account for your desire to test exactly at 4Vrms.
My desire? The whole world of consumer hifi has standardized on 4 volt output. Pro gear goes way above that. It seems like the AV manufacturers got together in a back alley and decided to shrink the output as much as they pleased.

I have $150 DACs that output 4 volt output designed by a single individual. When did this get "hard" as to want to relax the standard set in music world?

To get state of the art performance where you have true reference levels and dead quiet noise floor you need to go higher in voltage. Here is the Purifi Amplifier: https://www.audiosciencereview.com/...easurements-of-purifi-1et400a-amplifier.7984/

Here it is with 4 volt input:

index.php


This is what happens when you disable the input buffer and gain drops to 12 dB:

index.php


You get 4 dB in noise performance.

Same is true of Benchmark AHB2 amplifier:

1581558535222.png


Best performance is reached in Low Gain that requires nearly 10 volts and you are advocating for even less output than 4?

Here are the specs for RME ADI-2 DAC:
1581558629845.png


That's 6.9, 3.46, 1.7 and 0.9 volts.

Why would the AV industry want to not only miss the Pro standard, but also dip way below consumer music standard?

You are new here but this is an old topic here. My stance is firm. If dirt cheap music DACs can produce 4 volts, the AV world better wake up to that as well. HTP-1 seems to be there by letting me input 7 volt sensitivity in the menu but clips way before that?

Now, if you could show me how I have saved $2000 by accepting lower output levels that would be one thing. But there is no evidence here. It is just a crappy design standard set among manufacturers. As reviewers, last thing I want to do is help them in that regard.
 

Srrndhound

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Ah, it is clipping. The filtering in linearity test was hiding that. That's even worse. It clips at even 1 dB on the volume!
From what I have read, the goal of the Amp Sensitivity setting is to put the HTP-1's clipping point just above where the amp starts clipping.

My concern is that it requires care to get that right, especially when there's no easy way for a user to verify in a system with various power amps of ambiguous sensitivities.
 
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From what I have read, the goal of the Amp Sensitivity setting is to put the HTP-1's clipping point just above where the amp starts clipping.
Thanks. As I noted, I have set it to highest it would go (7 volts) but it is clipping around 4 volts.
 

Sancus

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I am not a huge fan of upmixing music. I prefer to listen natively in most cases. In others, Auro3D/Auromatic is the most pleasing to my ears.

Just curious, have you heard Logic7 or got access to the new JBLs with Logic16 at any point?
 
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A test I want to see is for example if you limit Dirac to your room transition frequency and then for some reason you want to change the level of the subwoofer. How are the filters applied?
So I took a shot at analyzing the bass management. Here are the results with the default 80 Hz crossover frequency:

Monolith by Monoprice HTP-1 16-Channel Home Theater Processor Bass Management Audio Measurements.png


It looks like the actual crossover frequency is 74 Hz rather than 80.

I analyzed the summed outputs of the sub and mains and as you see from inset graph, the error is quite negligible (0.04 dB worst case).

What else would you like me to measure?
 
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