Monoprice HTP-1 Home Theater Processor Review

[Matthew J Poes]

You mentioned dedicated stereo subwoofers and I couldn't help but link this Audioholics article about the compromises inherent in stereo subs - I thought it was very well researched: https://www.audioholics.com/room-acoustics/stereo-bass

Thats my article, glad you liked it. It was years in the making. The topic is so complicated that when I first began to explore it, my editors at multiple magazines told me nobody else would care. It was my deep desire to write that article but in a way that the average enthusiast could understand the concept enough to make sense of it.

What really drove me to write this, beyond my own understanding changing, was the misinformation on both sides. In one camp was an argument that bass is not stereo and pointless, which is wrong and misunderstands what and how we hear at low frequencies. On the other hand, there were those who argued that stereo bass was necessary and their assertion often rested on an over-simplification and mis-statement that stereo bass is audible as left-right panning at low frequencies. Something that is not correct. Pretty much nobody was arguing the correct point. You had David and a kind of response by Floyd, and that was it. Why? because the topic is seriously dense.

 

[Matthew J Poes]

An interesting article, thanks.

I currently run dual mono subs across the front wall at 1/3 and 2/3 positions and get excellent, even bass response. Mains (BG Radia 520i and 220 dx) are crossed over at 80 Hz and in-wall (BG Radia PD6-LCRi) surrounds at 50 Hz. If this is surprising, those are the 6dB points for all speakers: the surrounds actually have slightly larger woofers than the mains.

I was considering moving the existing subs to a similar position along the rear wall, for mono bass, and augmenting with stereo subs in the front, crossed over at between 160 and 200 Hz, to get the best of both worlds, and effectively running the fronts full range, particularly for music. Then again I might stick with mono bass in the front and just upgrade the subs.

You might consider looking at my article, linked above, and reconsidering this approach a bit. You won't be able to run them at the same time, the monosubs will supersede the stereo setup. Instead, what I would do is set it up for both (if you want this), with the stereo subs at the midpoint of the sidewalls instead. This works well for stereo bass. The 1/3-2/3 points do not work well for this. The stereo subs and the mono subs should be setup such that you can switch between them, both can't operate at the same time and get optimal results. If optimized for stereo, the mono bass won't work as well. If optimized for mono, the stereo bass won't work as well.

I haven't tried this with the HTP-1 processor and I am not sure how it can be done. With an Emotiva processor I played with, it was possible to use the outputs in this way and have a kind of pre-set that allows all subs to be used for Mono, and another that turned off the front and rear subs and only used the side subs with different trim levels and EQ for stereo. Something like that would be needed here too.

 

[markus]

Stereo bass below 80Hz is an exercise in futility. No mixing/mastering facility in this world is optimized for it nor does a significant number of people on the recording side care about it. It is a by-product of the recording technique at best. In fact most recordings contain just monophonic bass.
Reproducing "stereo bass" in an acoustically small room in a way that is true to the recording is exceptionally difficult and probably works only for a single seat, head-in-a-vice-style. The industry has bigger fish to fry. Reference level for music production, anyone?

 

[Matthew J Poes]

Stereo bass below 80Hz is an exercise in futility. No mixing/mastering facility in this world is optimized for it nor does a significant number of people on the recording side care about it. It is a by-product of the recording technique at best. In fact most recordings contain just monophonic bass.
Reproducing "stereo bass" in an acoustically small room in a way that is true to the recording is exceptionally difficult and probably works only for a single seat, head-in-a-vice-style. The industry has bigger fish to fry. Reference level for music production, anyone?

Again, you might consider reading my article. I suspect you may not be fully understanding what stereo bass is.

room size doesn’t matter. In fact if you read Davids articles on the topic, you will realize small rooms are far easier. He and I did experiments in bathrooms because it was the single easiest room to get the effect going quickly. It also wasn’t position dependent in a meaningful way. No more so than any other aspect of sound reproduction and absolutely not head in a vice like.

I also found hundreds of recordings that met Davids criteria for the effect to work. The studio doesn’t need a special mixing setup. They simply need either proper live recording techniques or a proper stereo reverb like the Lexicon units. Mixing for the effect can be done through headphones effectively. It can also be done such that the engineer never actually hears it. It isn’t dependent on their ability to hear it for it to exist.

it is far from futile. Worth it is another question. But not futile. I don’t happen to think it’s worth it given the music I listen to. It’s of uncertain but likely little value in movies as currently engineered. For music, while there are 100’s if not 1000’s of albums that work, there are many 1000’s that won’t. So if you listen to mostly modern music, for example, you won’t benefit. If you listen to a lot of Queen and Rolling Stones from the 70’s and 80’s, you could gain some benefit.

the effect is also extremely subtle and, as I noted in the review, not what most people think of when they think stereo.

 

[markus]

Again, you might consider reading my article. I suspect you may not be fully understanding what stereo bass is.

room size doesn’t matter. In fact if you read Davids articles on the topic, you will realize small rooms are far easier. He and I did experiments in bathrooms because it was the single easiest room to get the effect going quickly. It also wasn’t position dependent in a meaningful way. No more so than any other aspect of sound reproduction and absolutely not head in a vice like.

I also found hundreds of recordings that met Davids criteria for the effect to work. The studio doesn’t need a special mixing setup. They simply need either proper live recording techniques or a proper stereo reverb like the Lexicon units. Mixing for the effect can be done through headphones effectively. It can also be done such that the engineer never actually hears it. It isn’t dependent on their ability to hear it for it to exist.

it is far from futile. Worth it is another question. But not futile. I don’t happen to think it’s worth it given the music I listen to. It’s of uncertain but likely little value in movies as currently engineered. For music, while there are 100’s if not 1000’s of albums that work, there are many 1000’s that won’t. So if you listen to mostly modern music, for example, you won’t benefit. If you listen to a lot of Queen and Rolling Stones from the 70’s and 80’s, you could gain some benefit.

the effect is also extremely subtle and, as I noted in the review, not what most people think of when they think stereo.

Rest assured I've read most (all?) papers Griesinger wrote on the topic (http://www.davidgriesinger.com for anybody interested). It's not anything the recording industry at large is considering. And, the lack of rigorous scientific investigations and standardization isn't exactly helping.
There's a ton of cool things that could be done and found in recordings (for example stereo crosstalk cancellation – check out Part 1: Preprint No. 2420-A (B-10) and Part 2: Preprint No. 2420-B (B-10)) but there's also this annoying thing called "reality".

 

[bigguyca]

Unfortunately, we have been adding too many features to keep it up to date. We will publish a newone in October, that will need to be updated once DTS X Pro gets added, etc.

The good thing is the manual that's built into the unit is up to date with all the latest information.

Thanks for the update to the publicly accessible HTP-1 Manual. Having read the entire document IMO it's very well done.

It will be very helpful to the overall AV community, especially those considering purchase of an HTP-1, if the publicly accessible HTP-1 Manual is kept relatively up-to-date.

 

[bigguyca]

I will have to check with a dB meter. It could be that it's reserving 10dB or so for Dirac.

Edit:
My dB meter is a cheap one and the these are approximate figures.

With Dirac OFF at 2.2V I get ~72.5dB with the THX signal with the built in signal generator i.e. ~102.5dBFS at 0dB MV.
With Dirac ON at 2.2V I get ~66.5dB with the THX signal with the built in signal generator i.e. ~96,5dBFS at 0dB MV.

The same test with 2.9V I get 73.5dB and 68dB.
At 4.0V with Dirac OFF I get ~76dB. This is with an amp that should require 2.2V for max power. I don't really get it.

Your measurements with the SPL meter and voltage output setting of the HDP-1 are RMS measurements. 0dbFS as you are using it is based on sinewaves. That is with signals with a crest factor of 3dB. For example, if the V RMS at 0dBFS is 2V then the peak at actual digital max is about 2.8V or +3dB.

The THX signal is bandwidth limited pink noise with an RMS value of -30dB relative to the RMS value at 0dBFS rated with a sinewave. The crest factor of the pink noise is unknown to us. 6dB would be a typical crest factor, but we don't know.

As an example, if the crest factor is 6dB then you are measuring at -33dB relative to 0dBFS. +3dB actual digital peak - 6dB crest factor = -3dBFS as referenced to a sinewave.

For a simpler example, if the crest factor of the pink noise is 9dB then you are measuring at -36dB sinewave equivalent relative to 0dBFS. +30dB relative to the RMS value of the pink noise is actually -6dBFS in sinewave terms in this example. If you set the HTP-1 output at 2.2VRMS maximum then with your test setup you are getting 2.2V at 0dBFS or 1.1V at the -6dBFS actual output referenced to a sinewave.

Power amplifiers are rated with sinewaves so all of the inputs have to be sinewaves for testing or the crest factors of the actual inputs need to be known. While RMS is used to rate amplifiers it is actually the peak of the input wave that is important. Since this peak is +3dB for all sinewaves, it is much easier to just use RMS values since out typical thinking involves sinewaves.

Hopefully the above makes sense.

 

[DLxP]

Thanks for the update to the publicly accessible HTP-1 Manual. Having read the entire document IMO it's very well done.

It will be very helpful to the overall AV community, especially those considering purchase of an HTP-1, if the publicly accessible HTP-1 Manual is kept relatively up-to-date.

So I went and had a look at the manual, partly out of curiosity given you said you read the entire thing.

When I saw it was 97 pages I couldn't understand why you'd read all of it ... then I ended up doing the same!

I've got to agree, that's an unusually excellent and well-considered manual. It's genuinely increased my interest in the HTP-1. Partly as it shows how flexible it is, partly as it speaks to the competence of the designers.

 

[stunta]

Did you find anything in the manual that was useful and not obvious just playing around with the web interface?

 

[audioBliss]

Your measurements with the SPL meter and voltage output setting of the HDP-1 are RMS measurements. 0dbFS as you are using it is based on sinewaves. That is with signals with a crest factor of 3dB. For example, if the V RMS at 0dBFS is 2V then the peak at actual digital max is about 2.8V or +3dB.

The THX signal is bandwidth limited pink noise with an RMS value of -30dB relative to the RMS value at 0dBFS rated with a sinewave. The crest factor of the pink noise is unknown to us. 6dB would be a typical crest factor, but we don't know.

As an example, if the crest factor is 6dB then you are measuring at -33dB relative to 0dBFS. +3dB actual digital peak - 6dB crest factor = -3dBFS as referenced to a sinewave.

For a simpler example, if the crest factor of the pink noise is 9dB then you are measuring at -36dB sinewave equivalent relative to 0dBFS. +30dB relative to the RMS value of the pink noise is actually -6dBFS in sinewave terms in this example. If you set the HTP-1 output at 2.2VRMS maximum then with your test setup you are getting 2.2V at 0dBFS or 1.1V at the -6dBFS actual output referenced to a sinewave.

Power amplifiers are rated with sinewaves so all of the inputs have to be sinewaves for testing or the crest factors of the actual inputs need to be known. While RMS is used to rate amplifiers it is actually the peak of the input wave that is important. Since this peak is +3dB for all sinewaves, it is much easier to just use RMS values since out typical thinking involves sinewaves.

Hopefully the above makes sense.

Aha ok I see what you are saying and that makes sense. That is I understand what you are saying about the crest factor but I'm calibrating with a THX pink noise(I've never really thought about the crest factor in the pink noise before for some reason). In the end I still have the question. Given I have an amp that's rated at 2.2Vrms for max power(that's my interpretation of Ncore NC400 specification). What voltage would I have to set in the HTP-1 to get reference level at 0dB MV? From what I know this is typically done with pink noise that is calibrated to be -30dBFS(I don't know the default/optimal crest factor here). The THX pink noise in the HTP-1 should be the default whatever that is. But I have to set the voltage to around 4V output in the HTP-1 to get around 75dB with a signal like that.

In the end I'm still confused about how much digital headroom I have, what voltage my amps are actually getting and most of all what is the de facto way of doing this is. I.e. what would a professional calibrator set the levels to? Would they for instance turn up the gain of all the channels that Dirac has set (keeping the relative volume the same between channels) or what is the correct way of doing this? I'm not sure how much headroom I have to play with in the different domains.

The processor is working fine for me but I am still curious to what the optimal setup of the gain structure would be and how to calibrate to exact reference level with main volume at 0dB

I would be happy for anyone to correct my thinking below (or fill in the missing variable).

I have 92dB efficient speakers that are 4Ohm nominal.
I have an amp that gives me 400W at 4Ohm at 2.2V
4m from speaker to ear.

92dB 1m
89dB 2m
86dB 3m
83dB 4m
First I subtract 3dB for every meter to take height for the listening distance.

83dB 1W
86dB 2W
89dB 4W
92dB 8W
95dB 16W
98dB 32W
101dB 64W
104dB 128W
107dB 256W
Doubling of power for every 3dB gives me that I should reach reference level peaks of 105dB well within speaker and amp limits. 256W is well below amp limit of 400W and therefore well below 2.2V and this is even above reference level peak of 105dB.

 

[DLxP]

Did you find anything in the manual that was useful and not obvious just playing around with the web interface?

I don't have the web interface to play around with (I don't own the HTP-1, but am considering it).

 

[gags11]

Aha ok I see what you are saying and that makes sense. That is I understand what you are saying about the crest factor but I'm calibrating with a THX pink noise(I've never really thought about the crest factor in the pink noise before for some reason). In the end I still have the question. Given I have an amp that's rated at 2.2Vrms for max power(that's my interpretation of Ncore NC400 specification). What voltage would I have to set in the HTP-1 to get reference level at 0dB MV? From what I know this is typically done with pink noise that is calibrated to be -30dBFS(I don't know the default/optimal crest factor here). The THX pink noise in the HTP-1 should be the default whatever that is. But I have to set the voltage to around 4V output in the HTP-1 to get around 75dB with a signal like that.

In the end I'm still confused about how much digital headroom I have, what voltage my amps are actually getting and most of all what is the de facto way of doing this is. I.e. what would a professional calibrator set the levels to? Would they for instance turn up the gain of all the channels that Dirac has set (keeping the relative volume the same between channels) or what is the correct way of doing this? I'm not sure how much headroom I have to play with in the different domains.

The processor is working fine for me but I am still curious to what the optimal setup of the gain structure would be and how to calibrate to exact reference level with main volume at 0dB

View attachment 93671
I would be happy for anyone to correct my thinking below (or fill in the missing variable).

I have 92dB efficient speakers that are 4Ohm nominal.
I have an amp that gives me 400W at 4Ohm at 2.2V
4m from speaker to ear.

92dB 1m
89dB 2m
86dB 3m
83dB 4m
First I subtract 3dB for every meter to take height for the listening distance.

83dB 1W
86dB 2W
89dB 4W
92dB 8W
95dB 16W
98dB 32W
101dB 64W
104dB 128W
107dB 256W
Doubling of power for every 3dB gives me that I should reach reference level peaks of 105dB well within speaker and amp limits. 256W is well below amp limit of 400W and therefore well below 2.2V and this is even above reference level peak of 105dB.

I am a bit confused, what do you mean subtract 3db to take height when doubling the distance? I thought doubling distance results in 6db drop in sound, so for 4 meters, it will be 12db drop. Am I missing something else?

 

[Vasr]

FYI: Monoprice is selling the HTP-1 B-stock at $3400. I believe B-stock units get the full warranty as new.

 

[DLxP]

Yep, and they're in as new condition with complete repackaging. Mine should be arriving soon

 

[nuport]

Can those of you who own an HTP1 please comment on 2 channel performance? My priority is listening to music, but I recently have also moved to a place big enough to have a modest home theater set up.

I have a pair of DD8C's on the way and am trying to figure out if I should run something like a Minidsp SHD for 2 channel and a separate prepro for home theater with an XLR switcher, or if the HTP1 is good enough as an all in one solution. I'm worried I'll be leaving performance on the table with a speaker like the 8C.

 

[audioBliss]

Can those of you who own an HTP1 please comment on 2 channel performance? My priority is listening to music, but I recently have also moved to a place big enough to have a modest home theater set up.

I have a pair of DD8C's on the way and am trying to figure out if I should run something like a Minidsp SHD for 2 channel and a separate prepro for home theater with an XLR switcher, or if the HTP1 is good enough as an all in one solution. I'm worried I'll be leaving performance on the table with a speaker like the 8C.

The HTP-1 is for sure good enough. I've previously felt like my AVRs have been a bottleneck but not with the HTP-1. With Dirac Live Bass Control and multiple subs 2 channel is the best it's ever been in my current room.

 

[Dherrmann717]

The HTP-1 is for sure good enough. I've previously felt like my AVRs have been a bottleneck but not with the HTP-1. With Dirac Live Bass Control and multiple subs 2 channel is the best it's ever been in my current room.

I agree 100%. My music comes from my FLAC files via Roon, and the 2-channel is awesome. But, to be honest, I always listen to 2-channel with my HSU VT15 subwoofer. And, yes, I use Dirac DLBC, which just adds to the experience.

 

[lashto]

Can those of you who own an HTP1 please comment on 2 channel performance?
...
I'm worried I'll be leaving performance on the table with a speaker like the 8C.

In terms of fidelity/distortion, the speaker is by far the worst component in your chain. The best speaker ever is orders of magnitude worse than even the shittiest contemporary DACs. Even turntables have better fidelity/distortion than speakers. So no, there is absolutely no "performance" to be "left on the table" in your speakers. Or in any speaker known to man.

Considering that the distortion in the playback chain is (mostly) additive, you might still get some (audible) gains from using a high-quality DAC/Amp/etc. However, the DACs in the Monoprice HTP and Minidsp SHD measure in the ~same ballpark and most probably both have inaudible 'issues' and are indistinguishable from each other. Unless you have a trusty (and preferably 'blind') source that heard diffs between those two, the safe assumption is that they'll sound the same. And an extra MiniDSP will be a waste of time, money, cables, etc...

Good luck & have fun.

P.S.
you will miss something in a 'HTP only' setup: a streamer. Unlike pretty much all other 2020 receivers/processors, the HTP has very limited streaming capabilities, only bluetooth and Roon (IMO, a serious miss/flaw in terms of all-in-one comfort). You'll need an extra streamer: RPi, chromecast, AppleTV, whatever...

 

[hmt]

Well, that is the downside of the SINAD tables. People get in here and just look to have the longest bar without a hint of understanding what SINAD means and what its significance is.

 

[Duraace9sp]

Well, that is the downside of the SINAD tables. People get in here and just look to have the longest bar without a hint of understanding what SINAD means and what its significance is.

To (also) piggy back onto nuport's question above on Nov 29th and the following responses: Ok

Re - Noted in context to nuport's question about would you have an audible improvement if you had a dedicated 2 channel DAC. Based on these handful of responses the consensus is adding even a very good DAC would not an audible improvement.

Next and a factor on HTP1 vs others is ease of use and glitches - Im also looking for an AVP that you turn on and it works. While I am (was) ok with 5 remotes (or more) on the table - it alienated my wife from the TV room and system. Now we are rebuilding (retaining amps and speakers). I want very good audio (2 channel. She wants sit down grab remote and turn on - all done except select program. Im not certain anything works this seamlessly? My Anthem D2V did not......

Any feedback - as always appreciated - including on nuports questions......