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Monoprice HTP-1 Home Theater Processor Review

A/V Analysis

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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 always known +4dBu to be the pro standard (+4dBu with up to 20dB of headroom). At 3.875V the HTP-1 is outputting exactly 14dBu (10dB headroom over +4dBu).

Please help me out with a link or document number (I am both an AES and CTA member). I cannot find any reference to a 4Vrms (+12 dBV) consumer line level standard. If this is the case it is possible that Monoprice will switch from dBu to dBV as their standard unit. As I have shown, the unit will put out 4V without clipping. It was just your method of trying to get to 4Vrms that bumped you over into clipping. Since the HTP-1 volume increments in 1dB steps, it was skipping right over 4.0V going from 14dBu (3.875V) to 15dBu (4.36V) which we now know is in the clipping range.
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/
No disagreement from me. I agree 110%. But it should be noted that all of the 16ch immersive processors that output +18dBu (6.15V) or higher all list at $12k USD or higher.
(BTW, the Purifi is quite impressive!)
Thanks. As I noted, I have set it to highest it would go (7 volts) but it is clipping around 4 volts.
I think you missed where I took issue as well:
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.
There does need to be further clarification from Monoprice regarding this setting.
 

A/V Analysis

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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

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.
@amirm your thoughts?
 

A/V Analysis

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Just curious, have you heard Logic7 or got access to the new JBLs with Logic16 at any point?
Yes, I have heard Logic7 in various processors. At first, I found it not much different from Dolby Pro-logic II (H/K AVRs). However, only the Lexicon MC-4/8/12 had the full complement of adjustable parameters and it was much more impressive than I had originally experienced. The Lexicon MC10 is a rebadged Arcam. Its Logic7 is generic, without the "Lexicon" adjustable parameters. I have a feeling Logic16 will be the same.

I have not yet experienced Logic16 but I will once the JBL Synthesis Arcams (replacing the Lexicon of last year) are released.
 
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amirm

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Please help me out with a link or document number (I am both an AES and CTA member). I cannot find any reference to a 4Vrms (+12 dBV) consumer line level standard.
The origin of the specification came from Sony/Philips recommendation for unbalanced output being 2 volts with the introduction of CD. You can see that in the specs of the first CD player, the Sony CDP-101:

1581573114366.png


Make that differential and it becomes 4 volts. Search in this forum for balanced output and you will see countless measurements of products producing 4 volts over XLR.
 
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amirm

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@amirm your thoughts?
Yes, please keep new threads for them in appropriate subforum. If they are all home theater gear, then this subforum is suitable.
 

markus

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Please help me out with a link or document number (I am both an AES and CTA member). I cannot find any reference to a 4Vrms (+12 dBV) consumer line level standard.

In the consumer electronics space there is no standard to ensure proper equipment interoperability. There is not even a de facto standard most manufacturers would adhere to. That's the sorry state of affairs.
 

Gedeon

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I respect and envy @amirm knowledge a lot, really. Every single day. And obviously his relentless when measuring electronics.

On the other hand as @A/V Analysis and other members have written, AVP/AVRs doesn't aim the same standards.

I'm unable to listen a movie in my room with a volumen above -5dbs after the Audyssey calibration. My most common maximum is around -10dbs (70/100). In a small poll I did a year ago most AVR users share this numbers. Just one listens movies at 0dbs (80/100) in his room.

And multichannel domestic poweramps are rated to work at 1.2 volts input through RCA unbalanced connections. And this is IMO the key point. Poweramps don't expect more than 1.2 volts (with some headroom and a few exceptions).

And no one buys AVR/AVP just looking for a good DAC, although it is a key section in these electronics. Most look for multichannel decoding, HDMI switching, room correction, and another bunch of convenience features.
 

A/V Analysis

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The origin of the specification came from Sony/Philips recommendation for unbalanced output being 2 volts with the introduction of CD. You can see that in the specs of the first CD player, the Sony CDP-101:

Make that differential and it becomes 4 volts. Search in this forum for balanced output and you will see countless measurements of products producing 4 volts over XLR.
Ok, now I understand where the 4V is coming from. While almost all audio processors accept 4Vrms input that level is going to heavily clip most amps and destroy any connected speakers. This is why a pre-amp is necessary, and one should never connect a CD player directly to an amplifier.
In the consumer electronics space there is no standard to ensure proper equipment interoperability. There is not even a de facto standard most manufacturers would adhere to. That's the sorry state of affairs.
I searched the AES archive and read AES-R2-2004 (Revision of AES-R2-1998). It simply says that the nominal consumer level is -10dBV and professional is +4dBu irrespective of balanced vs single-ended. It also expresses desire to do away with the dBu unit and standardize the dBV.

3 Comment on the "dBu"
In spite of the widespread use of the abbreviation “dBu,” it causes considerable confusion, particularly among students and trainees, because it is based on the virtually obsolete technology (in professional audio) of 600 Ω iterative matching.
The working group has considered a suggestion that the AES Standards Committee should recommend the adoption of 1 V as the reference quantity for new work in audio engineering, corresponding to the level 0 dB (V).
While this recommendation is technically sound, the working group concludes that it is wildly idealistic because even "new work" must interface with "old" systems and engineers who consistently use 0,775 V as the reference quantity - the so-called "dBu." Therefore we have abandoned this suggestion.

Amir, had the HTP-1ut allowed 0.5dB steps in volume you would have likely been able to achieve 4V a bit easier (without clipping). In addition to 0.5dB steps, I would also prefer the output voltage at 0dB main volume match the Amplifier Sensitivity setting. Currently, I am reading 0.25V less. Presumably, to maximize output at 0dB MV without clipping the amp.
 

A/V Analysis

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I'm unable to listen a movie in my room with a volumen above -5dbs after the Audyssey calibration. My most common maximum is around -10dbs (70/100). In a small poll I did a year ago most AVR users share this numbers. Just one listens movies at 0dbs (80/100) in his room.

And multichannel domestic poweramps are rated to work at 1.2 volts input through RCA unbalanced connections. And this is IMO the key point. Poweramps don't expect more than 1.2 volts (with some headroom and a few exceptions).

And no one buys AVR/AVP just looking for a good DAC, although it is a key section in these electronics. Most look for multichannel decoding, HDMI switching, room correction, and another bunch of convenience features.
Audyssey aims to match the THX recommendations and sends -30dBFS test tones so this can get confusing. -10dB MV = 75dB SPL nominal, 95dB/105dB(LFE) peak. 10dB down from "reference" of 85dB SPL nominal, 105dB/115dB(LFE) peak.

I agree. The key point is that the majority of consumer amplifiers expect between 1.2V and 2V. The Nord (Purify): Input Sensitivity 8ohm 2.52Vrms 10.24dBu https://www.nordacoustics.co.uk/purifi1et400aamplifiers

Contrary to popular opinion, most companies are not profiting from the development and sales of processors. Processors sell amplifiers and there are many consumers who's OCD wants their components to match in the rack. Monoprice is going to optimize the processor to work with their own amps, input sensitivity: 1.6V.
 
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amirm

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Ok, now I understand where the 4V is coming from. While almost all audio processors accept 4Vrms input that level is going to heavily clip most amps and destroy any connected speakers. This is why a pre-amp is necessary, and one should never connect a CD player directly to an amplifier.
What? Just because the output is there, it doesn't mean you have to use it. Suggest reading this note from benchmark: https://benchmarkmedia.com/blogs/application_notes/balanced-vs-unbalanced-analog-interfaces

1581585117444.png


You cannot achieve state of the art signal to noise ratio with anemic output into an amplifier. John explains the reasoning well above.

Now, budget AVRs and such can be excused to not want to strive this high. But a $4,000 processor? If that is not "high-end" enough, what is?
 

A/V Analysis

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@amirm if I could get your opinion on this topic. All of the surround processor manufacturers appear to publish A-weighted measurements.

It appears that all of the other manufacturers in this space publish A-weighted numbers which seems to improve the numbers by ~10dB on the analyzer.

According to Rane, A-weighting is [only] appropriate for device employing ADCs and DACs (therefore all SSPs).
https://www.ranecommercial.com/kb_article.php?article=2121
Pro audio equipment often lists an A-weighted noise spec -- not because it correlates well with our hearing -- but because it can "hide" nasty hum components that make for bad noise specs. Always wonder if a manufacturer is hiding something when you see A-weighting specs. While noise filters are entirely appropriate and even desired when measuring other types of noise, it is an abuse to use them to disguise equipment hum problems. A-weighting rolls off the low-end, thus reducing the most annoying 2nd and 3rd line harmonics by about 20 dB and 12 dB respectively. Sometimes A-weighting can "improve" a noise spec by 10 dB.

The argument used to justify this is that the ear is not sensitive to low frequencies at low levels (à la Fletcher-Munson equal loudness curves), but that argument is false. Fletcher-Munson curves document equal loudness of single tones. Their curve tells us nothing of the ear's astonishing ability to sync in and lock onto repetitive tones -- like hum components -- even when these tones lie beneath the noise floor. This is what A-weighting can hide. For this reason most manufacturers shy from using it; instead they spec S/N figures "flat" or use the ITU-R 468 curve (which actually makes their numbers look worse, but correlate better with the real world).

However, an exception has arisen: Digital products using A/D and D/A converters regularly spec S/N and dynamic range using A-weighting. This follows the semiconductor industry's practice of spec'ing delta-sigma data converters A-weighted. They do this because they use clever noise shaping tricks to create 24-bit converters with acceptable noise behavior. All these tricks squeeze the noise out of the audio bandwidth and push it up into the higher inaudible frequencies. The noise may be inaudible, but it is still measurable and can give misleading results unless limited. When used this way, the A-weighting filter rolls off the high frequency noise better than the flat 22 kHz filter and compares better with the listening experience. The fact that the low-end also rolls off is irrelevant in this application. (See Digital Dharma of Audio A/D Converters)

Has this been discussed? I'm thinking it may be best to publish both A-weighted and unweighted. I also think it makes sense to measure at both 2Vrms and 4Vrms at a minimum. I think it is important for consumers to see the optimal operate ranges of a device. The matching of processor to amplifier is something many never consider.
 

audioBliss

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What else would you like me to measure?

There are so many things so I'm not sure where to begin. It's hard to sort out which are the most important since it would take too long to test everything. I've in the past had issues with channel imbalances on pre-outs so some sort of quality check there on how even the voltage between the different pre-outs would be interesting.
 

markus

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I searched the AES archive and read AES-R2-2004 (Revision of AES-R2-1998). It simply says that the nominal consumer level is -10dBV and professional is +4dBu irrespective of balanced vs single-ended. It also expresses desire to do away with the dBu unit and standardize the dBV.

Yep, that's all there is.

Pro: +4 dBu (1.228Vrms = 1.736Vpk = 3.472Vpp)
Consumer: −10 dBV (0.316Vrms = 0.447Vpk = 0.894Vpp)
 

A/V Analysis

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What? Just because the output is there, it doesn't mean you have to use it. Suggest reading this note from benchmark: https://benchmarkmedia.com/blogs/application_notes/balanced-vs-unbalanced-analog-interfaces

View attachment 50020

You cannot achieve state of the art signal to noise ratio with anemic output into an amplifier. John explains the reasoning well above.

Now, budget AVRs and such can be excused to not want to strive this high. But a $4,000 processor? If that is not "high-end" enough, what is?
I don't disagree with any of this. But the HTP-1 and AHB2 are not in the same class. Doesn't the AHB2 list for $3,000 (2ch)?
The HTP-1 is not a $4000 2ch processor. This is an "entry-level" 16ch processor. Imagine the cost of installing 8 AHB2s. I would love to be the salesman to a customer who thinks they need a 130dB dynamic range in their surround and overhead channels (let alone their mains).

We will soon see how the Lyngdorf MP-50 ($10,000), Bryston SP4 ($13,995), Trinnov Altitude ($17,000) stack up.

Many of the users I observe making judgements based solely on performance metrics <-100dB don't know their room's noise floor or Schroeder/transition frequency. If something is inaudible, does it matter?
 

Gedeon

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Audyssey aims to match the THX recommendations and sends -30dBFS test tones so this can get confusing. -10dB MV = 75dB SPL nominal, 95dB/105dB(LFE) peak. 10dB down from "reference" of 85dB SPL nominal, 105dB/115dB(LFE) peak.

I agree. The key point is that the majority of consumer amplifiers expect between 1.2V and 2V. The Nord (Purify): Input Sensitivity 8ohm 2.52Vrms 10.24dBu https://www.nordacoustics.co.uk/purifi1et400aamplifiers

Contrary to popular opinion, most companies are not profiting from the development and sales of processors. Processors sell amplifiers and there are many consumers who's OCD wants their components to match in the rack. Monoprice is going to optimize the processor to work with their own amps, input sensitivity: 1.6V.

Sadly, you are right, I'm sorry I'm confused about your explanation about db reference levels... ¿ Could you link a reading or explain it a bit more extended ?

Thanks in advance.
 

A/V Analysis

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There are so many things so I'm not sure where to begin. It's hard to sort out which are the most important since it would take too long to test everything. I've in the past had issues with channel imbalances on pre-outs so some sort of quality check there on how even the voltage between the different pre-outs would be interesting.
I may be in a better position to test this one for you as the APx-585 can track 8ch simultaneously. I already showed some examples with 2ch.
 

Gedeon

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@A/V Analysis

Thanks a lot for your patience. I think I've got it.

When I listen a movie at -10dbfs (70/100) volume level in an Audyssey calibrated setup, the dialogs, in average, would be about 75dbfs at my listening position. Main channels could reach 95dbfs peaks (LFE channel 105dbfs peaks).

¿ Correct ?

And in Denon/Marantz, if DynamicEQ is enabled (and set to 0 dbfs), when listening at -10dbfs, a subset of lower and higher frequencies will be "enhanced" to surpass those 95/105 peaks in order to get a closer response to a reference level volume, since I'm listening 10dbs below that reference.

¿ Correct ?

Thanks.
 

audioBliss

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Well I think that -10dBFS would actually mean 75/100 and 0dBFS would be 85/100. Movies at reference levels are still 85dB average and 105dB peak for consumer playback for all speakers except subwoofers where average level of LFE would be 95dB and 115dB peak (+ bass from other speakers). The LFE channel is 10dB higher. The main difference, as I understand it, is that for consumer gear all you need to think about is calibrating to 75dB since consumer gear uses -30dBfs pink noise. I.e. you don't have to calibrate at such loud levels because most peoples little speakers might be damaged etc.

However with Dirac I've read that it won't necessarily map your volume control to the correct number in the case you are using an Arcam which has the absolute scale 0-100. You'd have to post calibration verify which number is your reference level.

To clarify -30dBFS means -30dB from the peak of 105dB so 75dB. If you calibrate with a -20dBFS signal like in big cinemas your target would be 85dB. The standard for consumer gear is -30dBFS pink noise which means you should calibrate to 75dB. Both would result in the exact same dB at reference level. When measuring the volume you should use C weighting, slow if I remember correctly.
 
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