My year-long receiver/pre-pro experiment.

[mbah yai]

I'll start this off with some basics and maybe post more as it occurs to me. Over the last year or more I've been experimenting with a lot of options regarding sound quality with various ways of running my HT. I started using a Pioneer Elite VSX-56TXi receiver that I bought used here a couple years ago. This receiver was about $1,800 when it was new, 6 or 7 years ago, so it is far from a cheap piece of equipment. I have Thiel speakers in the front and use a very powerful Aragon amp for L&R that provides roughly 500 WPC. At first I was using the Pioneer to power the other speakers, which was a 5.1 system at the time. Actually, at first I had a Mission speaker for a center, because Thiel speakers are stinking expensive and the Mission made a decent, though hardly perfect match. The first interesting thing I found was that when I bought an Emotiva XPA-5 amp for everything other than the L&R, the Mission center now matched the Thiels far better than before. Not only does the Emotiva amp have more power, but it is a different basic design. Receivers ALL have class D amps, and the Emotiva is class A/B. I tend to be skeptical of the capabilities of EQ stuff like Audyssey. I see no way they can create the same difference as you get with a better amp. Wikipedia has a decent page explaining the basic differences in amp classes. The basic rule of amp classes is, high efficient class D amps are also complex and have relatively high distortion, but their big benefit is their efficiency. Then the designs step down in efficiency and distortion with class A/B and then class A. What I don't know is if the improvement in matching between the Thiels and Mission was due to the added power, better amp design or, most likely, a combination of both. The Aragon amp that drives the L&R Thiels is even a step above the Emotive, running Class A up to at least 100 watts (with the Thiels' impedance of abour 3 ohm) and A/B beyond that. The downside is that class A amps are absurdly inefficient at about 20-25% efficiency. Class D amps are usually at least 90% efficient. The problem is, I think (depending on your speakers) there is a genuine sonic difference. I suspect this is a big reason people hear such a difference when they go to external amps. It's not just the greater power, but a "smoother" sound from A/B amps vs. D. The next thing I tried was a newer receiver as a "Pre-amp" for the system. At the time, all the Marantz models had full pre outs, so I could use one in place of the Pioneer. So, I got a SR5005, the bottom of the line, for $500 (it's only $450 now) from accessories4less.com. Remember, I am using ALL external amps, so the receiver is really operating as a pre-amp. The surround sound was noticeably better than with the (older, but significantly more expensive) Pioneer. By "better" I mean on par with the difference between DVD and HD sound with BR. It wasn't subtle. What I don't know is if it is because the Marantz receivers are that good, or just that surround processors have improved that much. Once again, I suspect it is some of both. So, one of my conclusions is that it does make sense to use external amps, but use a receiver as a pre-amp. It seems silly, but pre/pros are expensive and if you can get 90% of the improvement with a good receiver that has pre-outs for the external amps it is more practical in the long run, especially since you can move that receiver to a smaller system when you upgrade. Today, I broke down and ordered Emotiva's UMC-1 pre/pro, which is on closeout because they are introducing a 3D compatible version. I guess I'll see if I hear an improvement over the Marantz receiver. Still, I was surprised what an improvement the Marantz was over the Pioneer when using external amps.

 

[RichB]

Welcome to the forum.

Using a AVR as a preamp is the most cost effective solution.
I tried a ICE based D-Sonic with my Revels a few years back and something was not quite right with the bass.
I settled on a Parasound A51 and I love it.

A friendly suggestion: please consider breaking your post up into paragraphs to make it easier to read.

- Rich

 

[crossedover]

Just a note to OP the pioneer you have is a MOSFET A/B amp not class D and all receivers are not class D

 

[AcuDefTechGuy]

The EMO probably has a higher voltage gain. You probably did not level match all the channels before. Actually, I keep my Center channel level about +2.0 above the rest for dialogue.

I my 30 years experiment, I see no significant improvement with any amps. Sure, there may be some differences, but once the levels are matched and the comparison is fair (no EQ or DSP, but in Direct mode), I see no significant improvement.

 

[rojo]

What I don't know is if it is because the Marantz receivers are that good, or just that surround processors have improved that much.

Debates about different DACs and other types of preamps, as well as different receivers in pure direct mode, are pretty common. Skeptics claim that if the sound on one is warmer, then there must be some sort of inaccuracy in the reproduction -- a subtle boost in the midrange, or a subtle difference in the compared volumes perhaps; or even a preconception influencing the preference. Oftentimes, people hear what they expect to hear. But even if both device A and device B measure flat and have matched volume, then one can be perceived as warmer than the other.

Why is this? I'm not sure. It could be that one device has beefier capacitors to handle peaks with less clipping. Or maybe one has a faster slew rate than the other. Marantz is awfully proud of their high slew rates on their SR series receivers, and those receivers are often perceived as warm. I have no other receiver with which to compare mine, but I have no complaints.

General question to all: when you come across such a discussion about whether receiver A sounds warmer than receiver B, is your first thought that the listener is doing it wrong or is nuts? Or do you accept that there may be a quantifiable difference -- perhaps not measurable with a frequency response graph or an SPL meter, but maybe that the slope of the waveforms are different between the two?

 

[Nestor]

Debates about different DACs and other types of preamps, as well as different receivers in pure direct mode, are pretty common. Skeptics claim that if the sound on one is warmer, then there must be some sort of inaccuracy in the reproduction -- a subtle boost in the midrange, or a subtle difference in the compared volumes perhaps; or even a preconception influencing the preference. Oftentimes, people hear what they expect to hear. But even if both device A and device B measure flat and have matched volume, then one can be perceived as warmer than the other.

Why is this? I'm not sure. It could be that one device has beefier capacitors to handle peaks with less clipping. Or maybe one has a faster slew rate than the other. Marantz is awfully proud of their high slew rates on their SR series receivers, and those receivers are often perceived as warm. I have no other receiver with which to compare mine, but I have no complaints.

General question to all: when you come across such a discussion about whether receiver A sounds warmer than receiver B, is your first thought that the listener is doing it wrong or is nuts? Or do you accept that there may be a quantifiable difference -- perhaps not measurable with a frequency response graph or an SPL meter, but maybe that the slope of the waveforms are different between the two?

Slew rate is only a factor when the dv/dt of the signal exceeds what the amp is capable of handling. This distortion is easily viewed on a scope. I don't recall slew rate being an issue in most modern amps.

IMO, if it can't be measured, it can't be heard. If it can be measured, a bias controlled listening test will confirm audibility.


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[Goliath]

The EMO probably has a higher voltage gain. You probably did not level match all the channels before. Actually, I keep my Center channel level about +2.0 above the rest for dialogue.

I my 30 years experiment, I see no significant improvement with any amps. Sure, there may be some differences, but once the levels are matched and the comparison is fair (no EQ or DSP, but in Direct mode), I see no significant improvement.

Clearly your speakers are not resolving enough or transparent enough to allow the fine details to shine through your amplifiers. Also, your ears may not be sensitive enough to hear the differences!?

Even the wife can hear the differences between amps, upstairs, in the bathroom which is situated about 20 meters away. Sheesh.

 

[RichB]

Debates about different DACs and other types of preamps, as well as different receivers in pure direct mode, are pretty common. Skeptics claim that if the sound on one is warmer, then there must be some sort of inaccuracy in the reproduction -- a subtle boost in the midrange, or a subtle difference in the compared volumes perhaps; or even a preconception influencing the preference. Oftentimes, people hear what they expect to hear. But even if both device A and device B measure flat and have matched volume, then one can be perceived as warmer than the other.

Why is this? I'm not sure. It could be that one device has beefier capacitors to handle peaks with less clipping. Or maybe one has a faster slew rate than the other. Marantz is awfully proud of their high slew rates on their SR series receivers, and those receivers are often perceived as warm. I have no other receiver with which to compare mine, but I have no complaints.

General question to all: when you come across such a discussion about whether receiver A sounds warmer than receiver B, is your first thought that the listener is doing it wrong or is nuts? Or do you accept that there may be a quantifiable difference -- perhaps not measurable with a frequency response graph or an SPL meter, but maybe that the slope of the waveforms are different between the two?

Auditory memory is really difficult and even with level matched quick switch A/B comparisons it is difficult.

A/b switching is useful but so is extended listening. There have been times listening to my system in the background, I suddenly felt, something is not quite right. An sure enough, I had the wrong driver loaded in J River.

Amp testing is particularly difficult, but I have used both methods.
Generally, I play intros of many songs at two volume levels. Moderate and extreme and take notes. For example, comparing the Outlaw M2200 mono-blocks to a Parasound A51 (2 channel) driving a pair of Revel F206's at high volume the M2200 were unpleasant and the A51 was lovely.

I had an Marantz AV8801 that I used in Pure Direct mode and it was fine. But basically, a glorified HDMI switch. After the second trigger repair, I sold it. I also found the center channel dialog was excessively sibilant in a way that was different from the Onkyo PR-SC5507 and BDP-105D (as a preamp). I noticed it immediately.
I had no preconceived notion other than that this new AV8801 was the best thing since ice cream

For two channel, I did some comparisons of the AV8801 7.1 analog inputs via the AV8801 and also using the HA-1 as a preamp. An XLR switch was used for A/B. These were very similar. When level matched, you might not know that I made the switch. Still, the HA-1 was a tad smoother on the upper end. Could I pass a SBT, probably not.

However, when compared to the HA-1 (with Linked simultaneous USB/DAC playback) the difference were much more pronounced. Could I pass a SBT, definitely.

All these products measure extremely well in professional reviews. However, none tested the center channel, nor do they perform multi-tone harmonic distortion tests. I have seen some measurements on HomeTheaterHifi of the AV7701 that showed increased harmonics over the previous models with two tone tests.

I suspect that multi-tone tests would reveal more significant performance differences in many products.

- Rich

 

[Goliath]

It could be that one device has beefier capacitors to handle peaks with less clipping. Or maybe one has a faster slew rate than the other. Marantz is awfully proud of their high slew rates on their SR series receivers, and those receivers are often perceived as warm. I have no other receiver with which to compare mine, but I have no complaints.

Receivers can be perceived as sounding warm, cold or sterile for no reason at all. Memes are usually the culprit - one guy pops into an audio salon, the dealer claims this or that receiver sounds 'warm' or 'bright', and then there is a following. More and more people then repeat these terms, because the salesperson biased them into hearing a difference, sort of like a self-fulfilling prophecy.

So it spreads, and spreads. Ever heard of Yamaha sounding 'bright'? Peruse the many audio forums and many, many, many people will claim that Yamaha sounds 'bright'. People say the darnedest things in audio. A change in perceived sound quality is not contingent on there being any actual sound quality differences - one can hear differences purely based on suggestions from others, memes spread around, what they read in a magazine, online reviews etc etc etc.

General question to all: when you come across such a discussion about whether receiver A sounds warmer than receiver B, is your first thought that the listener is doing it wrong or is nuts?

No, not nuts. Only human. The people who can't admit to being human could be accused of being nuts, but I certainly won't pass judgment!

Or do you accept that there may be a quantifiable difference -- perhaps not measurable with a frequency response graph or an SPL meter, but maybe that the slope of the waveforms are different between the two?

Look at it this way. All subjective anecdotes materialise out of grotesquely unreliable sighted conditions, and the common thread here is 'sighted conditions'. The person evaluating the gear engineers a difference that agrees with his own biases. Science can't measure something which isn't there, and I'm sure we can all agree on that. Every nebulous claim so far has been discredited in a professional blind test.

The fact that people can hear things even if nothing had changed is part of the problem. No differences need to exist in order for one to hear a difference between electronics. People have been able to hear differences between the same amplifier compared to itself! I've witnessed it! With my own eyes, with my own ears, many, many times over.

So when someone claims that amplifier A is 'warm' and amplifier B is 'sterile sounding', yes, the anecdote is meaningless and could be thrown in the proverbial bin. How you compare amplifiers is as or more important than the actual amplifiers themselves, because if there is no parity involved, you'll hear differences, whether they exist or not.

 

[3db]

Just a note to OP the pioneer you have is a MOSFET A/B amp not class D and all receivers are not class D

+1 Other then Pioneer and some slim line models, it would be more accurate to say that most AVRs are NOT class D.

 

[Goliath]

Could I pass a SBT, definitely.

What does 'SBT' stand for ?

 

[rojo]

Single blind test, I'd wager.

 

[Goliath]

I suspected single blind. Thanks.

 

[Goliath]

For two channel, I did some comparisons of the AV8801 7.1 analog inputs via the AV8801 and also using the HA-1 as a preamp. An XLR switch was used for A/B. These were very similar. When level matched, you might not know that I made the switch. Still, the HA-1 was a tad smoother on the upper end. Could I pass a SBT, probably not.

How did you level-match the equipment?

 

[RichB]

What does 'SBT' stand for ?

Single blind test, I'd wager.

You win

I am not overly concerned about xBTs because, for me, it has been about selecting gear for my system and professional reviews, respected member comments, and in-home trials have been enough since I am just trying to select components.

- Rich

 

[AcuDefTechGuy]

Clearly your speakers are not resolving enough or transparent enough to allow the fine details to shine through your amplifiers. Also, your ears may not be sensitive enough to hear the differences!?

Even the wife can hear the differences between amps, upstairs, in the bathroom which is situated about 20 meters away. Sheesh.

Why........you..........

My speakers are so transparent, my hearing is so sensitive, and all my senses are so keen and utterly reliable and infallible that I am able to hear things I shouldn't. I think I hear dead people.

So now I must sell all my speakers.

 

[AcuDefTechGuy]

Receivers ALL have class D amps, and the Emotiva is class A/B.

So for over a year of experimentation, you were biased into thinking that all receivers actually use class D amps?

Here, let me help - most receivers use class AB amplifiers, NOT class D amplifiers.

 

[cpp]

Why........you..........

My speakers are so transparent, my hearing is so sensitive, and all my senses are so keen and utterly reliable and infallible that I am able to hear things I shouldn't. I think I hear dead people.

So now I must sell all my speakers.

Watch out ADTG has Ninja skills

 

[AcuDefTechGuy]

Watch out ADTG has Ninja skills

View attachment 13597

I will use my ninja skills to slash my equipment list down to only 5 speakers, 1 AVR, and 1 amp.

 

[RichB]

I will use my ninja skills to slash my equipment list down to only 5 speakers, 1 AVR, and 1 amp.

The sacrifices one must make to achieve inner peace

View attachment 13598

- Rich