Monoprice HTP-1 Home Theater Processor Review

[Digital Mastering System]

I wish somebody would send an Outlaw Model 976 Processor to Amir so he could test it. The Outlaw power amps seem to test well. Seems like they care about their product's performance. Also helps the 976 is under $1000.

 

[SegaCD]

Do you hear room reflection in nature from sound source? If the answer is yes then why bother hearing the original signal?

Because room reflections are not always appropriate. If your audio scene takes place in an open field, jungle, etc. ignoring the higher-frequencies small room reflections can potentially ruin the information that actually hits your head.

What is needed is a test of the time constant on the mute function to ensure that it does not impact on real life use of the processor. Something that unmutes at signals as low as we see here is probably impossible to perceive in normal use.

Having a mute is interesting. I think this was suggested in discussion of the Emotiva, but it isn't impossible the processing chain mutes to prevent idle tones being generated in the face of very low to zero input. Same reason some DACs actually mute their output in the face of zero input.

This. If I bought this $4,000 device and was listening to my symphonic masterpieces at front-row live concert levels, I'd be fairly frustrated if I heard any sort audible effect of the muting circuit kicking in.

Honestly, while idle tones are certainly an issue with SDM DACs, the way they're being handled in this case is either a result of laziness or a hardware limitation. The muting circuitry should be handled by the data streaming processor and as soon as ONE bit of data on the input changes, the DACs should come out of mute. This isn't analog. A no signal situation is a no signal situation. Processors these days can definitely keep up with the data stream (or an FPGA on the decoder output...). Either the muting circuit is an old implementation and they think no one would care or there is a limitation (which makes no sense to me since all the technologies in the unit are quite modern).

 

[blueone]

My first reaction to reading this review was to recall the recent revelation of internal email criticisms of Boeing that included the statement:



However, that may be too harsh, and I think that we are seeing the results of a marketing company that hired journeymen electronics engineers. Monoprice is likely dedicated to profit first, and then minimum quality and performance to reach their revenue and profit goals, and not a company dedicated to producing the very finest A/V components and accessories. Their model seems to work well for many of their products such as cables. The below is from the Monoprice website.

I thought the HTP-1 was designed and built by ATI. It even says ATI on the rear of the unit.

 

[eycatcher]

Thank you for being the first to review this current product. Stinks you couldn't measure the HDMI input. Any chance on measuring the analog or USB inputs?

 

[RichB]

I thought the HTP-1 was designed and built by ATI. It even says ATI on the rear of the unit.

It is and built using an MDS platform for Dirac/DSP processing. The HDMI board may also be an MDS design.

- Rich

 

[RichB]

Because room reflections are not always appropriate. If your audio scene takes place in an open field, jungle, etc. ignoring the higher-frequencies small room reflections can potentially ruin the information that actually hits your head.



This. If I bought this $4,000 device and was listening to my symphonic masterpieces at front-row live concert levels, I'd be fairly frustrated if I heard any sort audible effect of the muting circuit kicking in.

Honestly, while idle tones are certainly an issue with SDM DACs, the way they're being handled in this case is either a result of laziness or a hardware limitation. The muting circuitry should be handled by the data streaming processor and as soon as ONE bit of data on the input changes, the DACs should come out of mute. This isn't analog. A no signal situation is a no signal situation. Processors these days can definitely keep up with the data stream (or an FPGA...or basically any sort of simple fast logic which latches when a bit of data changes will do). Either the muting circuit is an old implementation and they think no one would care or there is a limitation (which makes no sense to me since all the technologies in the unit are quite modern).

Emotiva has had issues with DSD steams. This could be an abundance of caution to avoid damaging gear.

- Rich

 

[Sancus]

The HTP-1 and JBL SDP-55 use the same Momentum Data Systems (MDS) DSP platform. The XMC-1 is based on an older MDS platform. It may be that JBL steps applies some pressure to correct the bit-dropping issue.

The emphasis on these processors seems to be on 16 channels which very few will ever use. Dirac processing is limited to 48kHz.
Matching the performance of a 2-channel desktop DAC is not on the feature list

I'm confused by this post. Where did I say matching the performance of a 2-channel desktop DAC is expected? This isn't a question of levels of performance, it's a question of working or broken. If you take 24-bit audio but truncate it to 15 bits, your DAC is broken.

Of course, it's not clear that's what's going on here, perhaps it is an artifact of the testing procedure. If that's the case, then I think it's actually a good performing product.

In any case, 16 channels isn't the reason I'm interested in the JBL, Dante and Logic16 combined with Dirac are.

 

[SegaCD]

Emotiva has had issues with DSD steams. This could be an abundance of caution to avoid damaging gear.

- Rich

Then this should apply only to DSD streams, not to PCM. There could totally be different muting profiles based on performance of different formats, and the profiles should be part of the firmware (which I hope they are here). Otherwise, its a major hardware issue.

I don't think this is a huge deal as it's a true edge case based on the assumption that as long as there is data in the upper-whatever bits of the i2s stream to the DAC in addition to the lower bits, there will be audio output (so you still have 24-bit precision in most situations), but I think it's a sign of lazy engineering. Not saying Monoprice has traditionally solved all the world's problems in the relatively cheap items they sell, but this is definitely one of the devices which is supposed to break them into higher-end audio and establish a name for themselves. Monoprice will struggle to sell this to folks who believe Monoprice represents a budget brand so I would have hoped they would have really tried to nail all the measurements. I would have expected an engineer to do a linearity sweep, see the obvious issue here, & do some additional research into this...but perhaps this whole thing was a solution that was contracted by an outside company (ATI?) and designed to just meet specs written on a sheet of paper (which is very, very much a thing & likely a thing Monoprice does for most of their products).

 

[Xulonn]

I thought the HTP-1 was designed and built by ATI. It even says ATI on the rear of the unit.

Now that brings up an interesting issue - what is the state of engineering at ATI, - and why are they risking their reputation by putting their name on a flawed $4k component?

When Amir tested, reviewed and recommended the ATI AT522NC stereo amplifier, he said this:

ATI builds amplifiers for many other companies and this competence shows up in this review.

 

[Francis Vaughan]

Now that brings up an interesting issue - what is the state of engineering at ATI, - and why are they risking their reputation by putting their name on a flawed $4k component?

Who says it is flawed?
This is a serious question. It is almost certain that the device does not truncate values to 16 bits. What it does do is apply a mute function that causes the linearity test to fail. One is a technical flaw, the other is an action that may be impossibly to perceive in real use. Calling the device flawed is doing it a serious disservice.

 

[Frank Dernie]

This. If I bought this $4,000 device and was listening to my symphonic masterpieces at front-row live concert levels, I'd be fairly frustrated if I heard any sort audible effect of the muting circuit kicking in.

I have thousands of music recordings, many I made myself.
I often have the level meters running when listening.
I have never seen a meter drop as low as -90dB on music, even symphonic properly recorded. That isn't to say there aren't any recordings with -90dB on them but I would be surprised. On pop music, of course it is much more likely to be between 0dB and -30dB. So I suspect nobody would ever hear the muting coming on, if that is what it is.
The irony is that most, maybe all, music recordings don't have as much as 16-bits of dynamic range whereas films with special super quiet studios to record the sound track might do whereas even inexpensive stereo DACs have a surfeit of performance for music the AVR devices, that may need more for films, do not.

 

[JW001]

If I bought this $4,000 device and was listening to my symphonic masterpieces at front-row live concert levels, I'd be fairly frustrated if I heard any sort audible effect of the muting circuit kicking in.
.

I don't think you would hear anything coming from the speakers at -90dBFS level, if you account for the background noise in your listening room.

 

[SegaCD]

I have thousands of music recordings, many I made myself.
I often have the level meters running when listening.
I have never seen a meter drop as low as -90dB on music, even symphonic properly recorded. That isn't to say there aren't any recordings with -90dB on them but I would be surprised. On pop music, of course it is much more likely to be between 0dB and -30dB. So I suspect nobody would ever hear the muting coming on, if that is what it is.
The irony is that most, maybe all, music recordings don't have as much as 16-bits of dynamic range whereas films with special super quiet studios to record the sound track might do whereas even inexpensive stereo DACs have a surfeit of performance for music the AVR devices, that may need more for films, do not.

Most microphones (especially dynamic mics) don't have self-noise levels below -90db. You're right!

At the same time, if you buy a $4,000 device (which I am not), you could be listening to boutique recordings, movies or music. Or maybe you listen to a lot of electronica/noise music.

I don't think you would hear anything coming from the speakers at -90dBFS level, if you account for the background noise in your listening room.

???

Assuming the recording isn't normalized to 0 dbFS (i.e. radio), what's coming out of your speakers won't exactly be -90dbA from the peak. Many recordings (acoustic in particular) have some headroom so that the data at -90dbFS will be an order of magnitude louder than you might expect.

Another case: if you have a media center PC and you control the volume using your PC like many of us do, -90dbFS might not represent -90dbFS from the audio track.

Regardless, I'm not sure why we're hand-waving this like it wasn't a conscious decision to mute at -90db. If it was a pure analog audio path & muting extraneous noise, you might have a reason. The point here is that it just shouldn't have been done especially at this price point. I usually try avoid lazy engineering approximations when I shell out $4k especially when there are dozens of A/V pre-pros in the market, most for less than this.

 

[Xyrium]

I thought the HTP-1 was designed and built by ATI. It even says ATI on the rear of the unit.

Yeah, perhaps ATI should stick with amplifiers only...they definitely shine there. Had one of their old shallow but wide units, 120W/ch, seemed solid, though the appearance was awkward if not rack mounted.

I think the whole purpose of the additional speakers is to swamp the room related effects by creating direct sound sources in 16 different places (in the case of Dolby Atmos), so the room does not need to add the ambiance b/c the surround speakers already do.

So, we're literally introducing the cancellation of sound on purpose? So, what becomes of the intended performance? "Is it real, or is it Memorex".

 

[Frank Dernie]

Most microphones (especially dynamic mics) don't have self-noise levels below -90db. You're right!

At the same time, if you buy a $4,000 device (which I am not), you could be listening to boutique recordings, movies or music.



???

Assuming the recording isn't normalized to 0 dbFS (i.e. FM radio), what's coming out of your speakers won't exactly be -90dbA from the peak.

Another case: if you have a media center PC and you control the volume using your PC like many of us do, -90dbFS might not represent -90dbFS from the audio track.

Regardless, I'm not sure why we're hand-waving this like it wasn't a conscious decision to mute at -90db. If it was a pure analog audio path & muting extraneous noise, you might have a reason. The point here is that it just shouldn't have been done especially at this price point. I usually try avoid lazy engineering approximations when I shell out $4k especially when there are dozens of A/V pre-pros in the market, most for less than this.

My comment is not justification for poor engineering just (my opinion) that so many people on this site seem to think things which will not be audible are some sort of catastrophe.
After all a lot of people like (and often believe superior) record players which are, at best 11-bit with plenty of audible distortion, or pay a fortune for reel-to-reel tapes which are not much better than LP and nowhere near CD in distortion or dynamic range.
Just my opinion/experience.

 

[SegaCD]

My comment is not justification for poor engineering just (my opinion) that so many people on this site seem to think things which will not be audible are some sort of catastrophe.
After all a lot of people like (and often believe superior) record players which are, at best 11-bit with plenty of audible distortion, or pay a fortune for reel-to-reel tapes which are not much better than LP and nowhere near CD in distortion or dynamic range.
Just my opinion/experience.

I agree. No arguments with you there.

I'm just a little frustrated that many people on here throw a DAC to the side if it has a 100 dB SINAD vs. a 120 dB SINAD (which may be due to accidental/circuit design experience but regardless is almost impossibly audible if its due to the noise floor or a couple low level harmonics), but then members are trying to justify this issue which was the certainly the result of a conscious decision someone at Monoprice, ATI, whoever designed the software made.

I also feel like it's another example of A/V pre-pros being all about features rather than performance, a trend which appears time and time again. Many on here hoped that maybe Monoprice would provide a unique solution and while the SINAD is the best so far in an A/V pre-pro, some of these quirks (from the linearity issue to the lack of acceleration in the volume knob) go to show that the A/V industry is all about getting that sweet, sweet Dolby/DTS/Dirac licensing cash and not much else. That's what is most disappointing about this.

 

[Sancus]

One test I'd like to see done on AVRs, although I think it can be done with something like Audacity and doesn't require any specialized hardware, is an audio latency test.

I play video games occasionally and I've seen some things that indicate latency in DSPs implementing Dirac can be 20+ ms, which is quite a bit. It's detectable around 15-30ms depending on the person, so it would be useful to know if most AVRs are below this threshold or not.

Is this the same Sancus that posted the review over on the AVS owners thread? It'll be interesting to see the responses.
.

Yep I'm on both forums

 

[Francis Vaughan]

The question is whether it is even poor engineering.

The likely reason for the behaviour is going to be the same reason given by Emotiva for exactly the same behaviour in their product. It isn't them. It is part of the function of a DSP library that they have licensed. I would not be surprised that under the covers a lot of the core function in many AV processors is the same processing chain software. Certainly the usual suspects, Dolby, DTS, Dirac etc - you don't implement this yourself, you license either t he software directly (Dirac), or a software library implementing the IP from another vendor who license the IP from the likes of Dolby and DTS. Sometimes the processing comes on a chip, sometimes as a library. None of these vendors is implementing the entire DSP chain themselves.
One might object that there should be a "pure" direct mode to direct input signals to the output without transiting any of these libraries. Sure, but to what end? Allowing for purist measurements? That is all it would do.
Be clear, once the system unmutes, the performance is going to have the base linearity the DAC provides. Getting tied up in knots about a "flawed" or "poorly engineered" product when no-one even knows what the time constant on the mute function is is just plain silly. In real life use it is almost certain that this is simply not an issue. The unit will unmute and that will be the end of it. Hit PLAY and the panther will grow a head.

 

[amirm]

Thank you for being the first to review this current product. Stinks you couldn't measure the HDMI input. Any chance on measuring the analog or USB inputs?

Does it work as a USB DAC?

 

[amirm]

Be clear, once the system unmutes, the performance is going to have the base linearity the DAC provides. Getting tied up in knots about a "flawed" or "poorly engineered" product when no-one even knows what the time constant on the mute function is is just plain silly.

What mute "function?" There is no such feature in the manual or specifications for the product. Nor is there any benefit to any user to have such an "auto mute" function.

And if you are going to have one, why draw the line at 15 bits/90 dB?

Why is there no indication on the display that some kind of auto mute is activated? Why is there no option to turn it off?

The only reason I know this is done is to cheat and make signal to noise ratio tests look good by muting low level signals. That is certainly not a benefit to users and is a common way to cheat in measurements.

As I indicated, there is a blinking status indicator of PCM samples. That tells me it may be having difficulty locking to input values.

Out of nearly 300 devices I have tested with DACs, only two have failed the test this way and both are AV Processors. No way this is a "measurement problem." No device that advertises at least 16 bits of resolution should auto turn off its output this way let alone 24 bits.

This problem needs to be properly identified and fixed. By defending it as a feature and not a bug, you are postponing or eliminating this opportunity. Nothing about this test is unusual or "test specific." A DAC has to be a DAC. You give it a -96 dB signal, it needs to produce a -96 dB signal.

Note that this test hugely favors manufacturers already. All noise and distortion is discarded in the capture and all it looks for is an amplitude that is correct. To fail even this test means that the unit is not working as advertised.

And no, this is not like a subwoofer auto-on. The sub will turn on and stay on. It doesn't keep turning on and off like this device does with no indication it is "muting."