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Monoprice HTP-1 Home Theater Processor Review

Martin

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You certainly would do way better with a dedicated power amp. Bi-amplifying on a receiver is just asking for it to perform at its worst. I used to run just a Denon X2200W and after upgrading, I realize I was pushing that receiver into distortion past -20dB.

I like reference volumes too, but my gain structure is matched up such that at -5dB on the T758, I am providing my A5175 with 1.2V which is what it wants for full power. I have never gone above -10dB for a few records, or movies. TV is obviously down closer to -30dB for comfortable listening. You should be able to match up either NAD with a great power amp that only needs 1.2V to stay out of the danger zone. I am in a small apartment and my speakers aren't crazy sensitive, so you probably don't need as much power as you think.

Also, Dirac really is worth it. I believe it makes the poorly measuring NADs sound better than almost every other receiver in the same class and below. The resolution differences to Audyssey XT32 aren't even comparable.

I'm now considering an NAD T 758 V3 with an Outlaw Audio 7000x amplifier. Seems like the least expensive way to get Dirac and the power I crave. Adding the Dirac Live full range upgrade and a miniDSP 2x4 would allow me to integrate and balance my pair of subs in the mix.

Martin
 

Sancus

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The manufacturer posted a response on AVSForum.

So, what'd I miss?
wink.gif


First off I'd like to thank ASR for the review. I am pleased that the HTP-1 is the best measuring AVP ASR has ever measured, even better than some offerings from bigger, more known brands. I also want to thank Marc for going to extra mile and measuring several of the processors in his possession. Marc and I had talked about doing that (since he seems to have all of them now, and yes, I'm jealous) and how interesting it would be long before the ASR review was published. Frankly, I was curious as to where the HTP-1 would stack up. As all can see from the myriad of measurements, the HTP-1 is certainly not a compromised product to hit a $3999 price point. Both cannot be true: The HTP-1 measures among or better than products that cost 3x-4x as much, and yet also be compromised to hit a much lower price point. There is absolutely nothing wrong with the core performance of the HTP-1.

A lot of the discussion has revealed and illustrated that there is confusion around the amp sensitivity feature, so we will be making a change to the software so this is more clear. This setting should never have accepted a 7V maximum as the maximum output of the HTP-1 hardware is just above 4V RMS. The next software release will change the UI to acknowledge this limit. Further, there was a half dB gain error in the calculation that left the 0dB voltage just under 4V. This will be corrected.

Early in development of the HTP-1, I made a statement that the output voltage would be 12V. This was completely factual at the time as early prototype boards were built this way, but when connected to real amplifiers it became clear that this capability raised the noise floor by nearly 20dB when connected to industry standard amplifiers like the Monolith series amps. The design was changed to better match the expectation of common, consumer grade amplifiers which are generally driven to clipping by signals less than 2V RMS. The HTP-1 is designed to drive amplifiers of this sort, and has been maximized to match perfectly with the Monolith amplifier gain structure (which a lot of other amplifiers follow too). I should have went back and corrected this as we were developing the product.

We could have left out the Amp Sense control and could have simply built it for a 4V RMS output, but for those with a 1.6V amplifier, this would have been an 8dB penalty. I decided it was best to give users the ability to align the HTP-1 with your amplifier.

Sorry for any confusion. We look forward to continued work on more substantial features.

I also think a fair criticism coming out of the ASR review and discussion is that we didn't publish specs of the HTP-1. Now why didn't I do that? I was more focused on the feature set and value for the $$, and not measurements. I will do a much better job in being transparent in the future. If the HTP-1 measurements are among the highest measured AVPs and products that cost 2x-4x as much, what were we hiding again? There is no conspiracy. Every production unit is measured for performance on every channel. By collecting all of the data, we are confident that the performance specifications that we release are accurate and representative of all units in the field. In fact, many of the units in the field will have slightly better performance than what we state officially.

Having said that, here are the specs, and I attached all the measurement graphs:

All measurements made on a representative production unit using an AP-585 with balanced outputs. Software version 1.3.1.

Frequency Response:
48kHz, HDMI input, 20Hz to -20kHz, +0.1 -0.2dB.

Total Harmonic Distortion and Noise at 1kHz:
48kHz, HDMI input, 1.8V output. (amplifier sensitivity 1.8V, output level 0dB)
0.00050% (106dB) *best
48kHz, HDMI input, 2.2V output. (amplifier sensitivity 2.0V, output level 0dB)
0.00051% (105.7dB)
48kHz, HDMI input, 4.0V output. (amplifier sensitivity 4.0V, output level 0dB)
0.0014% (97dB)

Signal To Noise Ratio/Dynamic Range:
48kHz, HDMI input, 2V output. (amplifier sensitivity 2.0V, output level 0dB)
114.8 dB A-weighted
111.1 dB CCIR-2k
48kHz, HDMI input, 4V output. (amplifier sensitivity 4.0V, output level 0dB)
116.1 dB A-weighted
112.2 dB CCIR-2k

Channel Separation:
48kHz, HDMI input, 2V output. (amplifier sensitivity 2.0V, output level 0dB)
Left channel driven. >110dB at 10kHz

Output Impedance: 180Ω

Maximum Output (balanced): 4.0 VRMS


I'm going to finish with saying something that many will find truly controversial and polarizing:

THE LAST JEDI is a masterpiece. :D

Some images of measurements were also posted.
 

RichB

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First off I'd like to thank ASR for the review. I am pleased that the HTP-1 is the best measuring AVP ASR has ever measured, even better than some offerings from bigger, more known brands.

There is some spinning.
At 4 volts it is not the best measured AVP, that is currently the XMC-1.
It is the only AVP shown at 2.7 Volts (which seems a bit arbitrary). If the others were measured at 2.7 volts, perhaps they would have had the best score. Another might do better at 3.2 volts. 2 Volts and 4 Volts are notable but a THD+N sweep is best for those that want to gain match.

- Rich
 
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amirm

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Is he aware of what a headless panther means? It cannot be the best if it does not get a recommendation IMO. Kind of shocked that this is the response and it's not even here, at the source.
I don't take his response as harshly. :) It is nice of them to correct the UI and such.

On your other point though, that he is not answering here, is disappointing. I worked with Hobie Sechrest to review their THX headphone amplifier which I gave the highest praise to. So he knows where I am and how to contact me. And that my judgements are fact based.

But we will live. :) There are other processors coming for testing so we can busy discussing those.
 

RichB

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I don't take his response as harshly. :) It is nice of them to correct the UI and such.

On your other point though, that he is not answering here, is disappointing. I worked with Hobie Sechrest to review their THX headphone amplifier which I gave the highest praise to. So he knows where I am and how to contact me. And that my judgements are fact based.

But we will live. :) There are other processors coming for testing so we can busy discussing those.

Any truth to the rumor that an RMC-1 is on the way?

- Rich
 
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amirm

amirm

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Just looked at the measurements which were performed using HDMI as opposed to AES that I used:

attachment.php


Look at the sidebands around the 1 kHz tone. It takes a heck of a lot of jitter for it to be visible that way at such a low frequency (of 1 kHz).
 
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amirm

amirm

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Maconi

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Is he aware of what a headless panther means? It cannot be the best if it does not get a recommendation IMO. Kind of shocked that this is the response and it's not even here, at the source.

It's the best receiver/processor measured (so far) on ASR, it just doesn't meet Amir's standard for audio equipment in general.

Hell, Amir himself even said he was close to giving it a "passing grade" but he didn't like the 15 bit issue. Then it was revealed that problem is easily resolved with a PCM setting. Once that hurdle was cleared it was discovered that there were issues with the Amp Sensitivity setting that would cause clipping/compressing so he still wouldn't be changing his recommendation. Now the manufacturer has released a statement saying that being able to set Amp sensitivity above 4V was a bug to begin with. They even released official measurement numbers which was another criticism placed against them.
Conclusions
I am hoping that the muting problem beyond 15 bits can be fixed with a firmware update. If so, and the video compatibility is not a broader issue, I would give HTP-1 a passing grade. As it is now, it is not ready for production.

EDIT: an obscure setting fixes the linearity/muting issue. This setting should be the default, not the other way around. I am still bothered by lack luster output level and distortion for a $4,000 product. So not changing my recommendation.

At this point it would be nice to go back in time and see the HTP-1 measured with the proper settings (PCM set to Biased/Indicated, Amp Sensitivity set to match a common paired amp likely around 1.5V-2V, reference volume, etc.) and over HDMI rather than AES (just to see if there's a difference) for the initial review just so we could skip a lot of the arguments/drama and focus on the final measurement numbers. What's done is done though.

EDIT: I wonder what's going on with the jitter? I assume the hardware is standard so it must have something to do with their implementation or firmware?
 
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RichB

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amirm

amirm

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At this point I'd be interested in seeing the HTP-1 measured with the proper settings (PCM set to Biased/Indicated, Amp Sensitivity set to match a common paired amp likely around 1.5V-2V, reference volume, etc.) and over HDMI rather than AES (just to see if there's a difference). I'm not sure if Amir will waste any more time on this unit though.
I have to return the unit tomorrow. If by some miracle I figure out how to make HDMI work, I will test it again that way.
 
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amirm

amirm

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EDIT: Looks like Amir beat me lol. I wonder what's going on with the jitter? I assume the hardware is standard so it must have something to do with their implementation or firmware?
Can't figure out any firmware fix for it.
 

doodlebro

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I don't take his response as harshly. :) It is nice of them to correct the UI and such.

On your other point though, that he is not answering here, is disappointing. I worked with Hobie Sechrest to review their THX headphone amplifier which I gave the highest praise to. So he knows where I am and how to contact me. And that my judgements are fact based.

But we will live. :) There are other processors coming for testing so we can busy discussing those.

Fair. It is better than most manufacturers who stay silent, though I imagine NDAs could be a hurdle there as well.
 

Maconi

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Could Tommy Two Tone have meant getting help with figuring out getting HDMI to work? Just asking...

I think Amirm might be suggesting he knows what he's doing and it's the unit's fault not his? I don't want to speak for him though.
 

TommyTwoTone

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Could Tommy Two Tone have meant getting help with figuring out getting HDMI to work? Just asking...
Yes. Similar to the PCM detection setting that Amir missed adjusting prior to taking his measurements there could be some setting that is ill-configured for testing purposes. Monoprice was able to obtain measurements with similar hardware so it's clearly possible.

A link to the manual might help:
https://downloads.monoprice.com/files/manuals/37887_Manual_200124.pdf
 
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amirm

amirm

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Could Tommy Two Tone have meant getting help with figuring out getting HDMI to work? Just asking...
Nah, he was just shifting blame. It is a tendency for some people to want to defend manufacturers than be on the side of users.
 
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