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Monoprice HTP-1 Home Theater Processor Review

Xulonn

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@amirm , am I correct in assuming that you test AV analog and digital electronics to see their electrical and data manipulation performance, and test speakers to measure their pseudo-anechoic performance - and that listening evaluations are only an occasional add-on to satisfy your curiosity?

It seems to me that if you were to try to evaluate the acoustic performance of components in a loudspeaker-based system (your primary home AV rig), that would be a whole 'nuther layer of time-consuming work. And since only double-blind ABx testing is truly worth anything from a scientific perspective, truly objective audio testing would be huge task with multiple volunteer listeners over many days of repetitive testing.

I see your work as an attempt to level the playing field in an environment where manufacturers play loose and easy with few standards and little to no enforcement. I like the fact that I can visit ASR and compare products that have been tested in a uniform manner, and where designers and manufacturers can come and confirm things, or plead their case if they disagree or dispute the findings.

ASR is a science-based (oriented?) web forum, not a hardcore science website per se. Anyone who has worked in science can easily see that. To mee, the professional engineers and designers who come here provide peer review, and the rest of us are like those who write comments at any science-reporting website.

I was called out for referring to the Monoprice AV processor as "flawed", but as long-time AV enthusiast who is not a technical professional in the field, I agree with others who have supported you in saying that this component - at $4k - could have done a few things a bit better. When you get up to 30 to 40 AV processors and receivers tested, we can take a better look at the matrix of test results and see where any particular unit stands in relationship to its "peers".
 

A/V Analysis

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Every audio component i have that has a dB scale will clip if set to a positive dB value. These settings are only used when playing a file which stays below 0dB (ie all the good ones...) and then only just!
My Devialet Phantoms, which do not have a dB scale, are advertised by the maker of producing maximum output at a setting of 70 (out of 100), which is more than i have ever used, with some sort of compression rolled in from 70 to 100.
Not AVRs. I have had to go positive scale on a number of them without clipping. It depends on the design. In this case you actually tell it in the settings how many dBs higher you want to go. Unless you set it, it won't let you go above 0 dB.
Agreed. Out of the box I believe the D+M do not clip (with 0dBFS input) until exceed +6dB volume. It is over +12dB on the NAD M15HD.

I confirmed with Monoprice that the HTP-1 was designed with small bit of digital headroom (0.5dB). One must set volume to +1dB to use this small bit of headroom. I'm performing all of my measurements with volume set to +1dB. I expected the analog volume control to kick in as I exceeded +1dB but it doesn't seem to be (~4.2V is the max I can achieve). I am reporting this to engineering for investigation.
 

Xulonn

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Most of what I test comes from owners so I don't feel any obligation to look the other way when it comes to equipment flaws. It is much tougher when you are loaned expensive gear and feel like returning the favor.

This is one of the major things that attracts me to ASR - it is consumer oriented and not industry-oriented. Most of the units you test reflect exactly what the consumer gets, and we have a right to know how random units in the field perform compared to marketing claims - regardless of their price, reputation, or the size and outrage of their owner and fan-base.

Any company whose product(s) perform poorly, or are not up to spec can come here and work with @amirm and the ASR community to explain things - and fix problems. When they do that, they go to the top of my list as ethical and honest organizations.

Also, the tolerance of some tube and other sometimes "non-accurate" AV gear fans here is appreciated, I often join in the effort to get such fans to learn to say "I don't care if the measurements are off - I like and enjoy my xxx amplifier or loudspeaker" without getting defensive, and without claiming that their system's sound is "better".
 
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amirm

amirm

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@amirm Apart from all this fuzz with monoprice, any chance to see a older prepro test from you? like the Denon Avp a1hdci?
First post here , so be gentle if i mess up on the forums .
I have a Lexicon 12B that I can measure if there is interest. I also have an older Anthem AVM-50 processor at our other house which I could get to test. I did a roundup a few years ago on them: https://www.audiosciencereview.com/...s/a-deep-dive-into-hdmi-audio-performance.56/

index.php
 
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amirm

amirm

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@amirm , am I correct in assuming that you test AV analog and digital electronics to see their electrical and data manipulation performance, and test speakers to measure their pseudo-anechoic performance - and that listening evaluations are only an occasional add-on to satisfy your curiosity?
That's correct. I am focusing on a hole in AV gear reviews where there is basically no objective measurements of their audio data paths. In this case, Dirac is licensed product and I already use that in my everyday music system so there is not much of interest to evaluate there. Yet as you noted, it takes a ton of effort to test it on this unit. In the past, I have reviewed different technology such as Lyngdorf RoomPerfect since I had not tested that before.
 

Costas EAR

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Amir, you have an excellent 5-channel setup as i recall, maybe you should give monoprice a try there, where you are familiar with the achieved sound quality.

After all, monoprice is the best measured av until now! ;)
 

Dj7675

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@amirm, does it ever make sense to test AVRs and processors also with DSP engaged since that is how the unit will most likely be used? Or would the results be the same?
 
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amirm

amirm

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@amirm, does it ever make sense to test AVRs and processors also with DSP engaged since that is how the unit will most likely be used? Or would the results be the same?
They likely perform resampling and attenuation (for headroom purposes), so it is worth testing. Only if I had more time to devote to them....
 

A/V Analysis

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I highly suggest you read more of what is posted here before running off with comments like this. You can start with the banner in the review tab that takes you to my series on room measurements: https://www.audiosciencereview.com/...om-measurement-tutorial-for-dummies-part-1.4/

After you are done with that, you can read more advanced articles like this one: https://www.audiosciencereview.com/...ds/perceptual-effects-of-room-reflections.13/
That is all great stuff! Impressive and commendable.

I am a professional calibrator, HAA and Smaart certified. www.homeacoustics.org www.rationalacoustics.com

Please don't misconstrue my intent. My goal is not to antagonize you. Rather, it is to cooperate and contribute here. My interests lay with the consumers, not the manufacturers.

@amirm
And no, the room doesn't add "distortion" unless there is some kind of rattle in there. The transformation is linear.[/QUOTE]
What is your definition of linear distortion?
@amirm how did you come up with the 2.7V level (rather than 2.0V) to determine how the HTP-1 measures at lower output? I've browsed several of your reviews where you do measure at 2.0V (not 2.7V AFAICT).[/QUOTE]
It was what I recall the Marantz specifying so I thought I start to use that as a lower bar.
Consider adding 2V measurements in addition to 4V for the benefit of those with consumer grade gear.
 
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amirm

amirm

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What is your definition of linear distortion?
No new frequencies are added. Best to not use the term distortion at all as it usually means non-linear.
 
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amirm

amirm

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Consider adding 2V measurements in addition to 4V for the benefit of those with consumer grade gear.
2 volts is for unbalanced. 2.7 volt that I used is for low setting of XLR output.
 

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....
@amirm are you planning to edit the original review? Some users are going to scan the review and never browse further into this thread.
 
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amirm

amirm

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@amirm are you planning to edit the original review? Some users are going to scan the review and never browse further into this thread.
An edit was put in a while ago:
1581718568035.png
 

A/V Analysis

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An edit was put in a while ago:
View attachment 50204
But your incorrect assessment of the behavior still remains. Less technical users are just going to latch onto 16-bit vs 24-bit and other incites
@amirm
I was called out for referring to the Monoprice AV processor as "flawed", but as long-time AV enthusiast who is not a technical professional in the field, I agree with others who have supported you in saying that this component - at $4k - could have done a few things a bit better.
@Xulonn, was this the flaw are/were referring to? I don't consider it a flaw. It is an artifact of the analysis. The APx-585 analyzer does not exhibit the same behavior as it has preset settling times enabled by default.

@amirm I am in love with the APx-500 v5.0 software! I don't think I can ever go back.
 

RichB

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Yes! The target consumers for the HTP-1 are using amplifiers ranging from 1.2V - 2.5V rms sensitivity and that is the optimal range of the HTP-1. You are going to flip your lid when you see how the Trinnov of StormAudio units measure at these low levels. I haven't completed the measurements but the basic SINAD (I see that ASR prefers the SINAD presentation over THD + Noise, so I will provide SINAD). It is at 4V and greater where they hit their stride (which makes sense as the Trinnov Amplitude amplifiers have a +18dBu sensitivity).

4 Volts is also a consumer target for balanced outputs.
If there is a sweet spot, then it should be published with the specifications. Better yet, show the THD+N for all power outputs. Some of us have amps with adjustable gain and this data is useful for gain matching.

- Rich
 
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