Home Theater Forum and Systems banner

61 - 80 of 251 Posts

·
Premium Member
Joined
·
5,794 Posts
I'm steadily growing on this bolded part. Power power power... more power... cleaner output. I'm beginning to wonder if 125w all channels driven if that really should be like 400w each channel that the Emotiva XPR-5 can deliver.

I can literally sell my Krell and buy a new Emotiva XPR-5 for the same price. Hmm....
ore power is only needed if you can't get to the levels you want cleanly with your current amp. With my current setup I actually went down on power as I do not need it to hit reference levels.
 

·
Banned
Joined
·
22,577 Posts
Sonnie said himself he has clipped the amp. Me... I've ran these SVS ultras to 105db playing pink floyd with the X4000 in direct mode and the volume set to +8db and never heard of any strain at all.
I clipped my X5200 with the Ultras. Perhaps I was listening at louder levels than 105dB... not sure. I plugged my Behringer EP2500 in the loop and there were no issues... problem solved. I wanted a better looking amp and got a really really good deal on a Parasound HALO A31, so I purchased it.


Not arguing that one or the views is absolute and carved in stone. But I thought the following quote from Lonnie Vaughn, Chief Technical Officer at EMOTIVA, offers a decidedly non snake-oil explanation for why amps sound different:

"Amplifiers do sound different for a number of reasons. Paul cites a good one, the square wave response. On a personal note, I believe the power supply plays a big part in the way an amp sounds. I get that the power supply accounts for the biggest part of an amplifiers cost. But so many companies take it down to the bare minimum required to meet the specs that there is no headroom in the system at all and the amp itself just sounds flat as a board. In these cases, all the designer had to do was put in a few dollars more in storage and it would have made it a completely different unit." (Taken from an article on this webpage)
I agree they will sound different if pushed really hard with certain speakers... in that one will clip, one will not. That is my experience... although someone else may hear something different for a different reason.


The Denon tested has a normal non toriodal type transformer and that ended up falling last by the posts that was made?.... is that still true?
Not sure where you got that... the Denon was well received. We did not attempt to push it to the limits. I don't think any of us have ever doubted that you can overdrive an amp and that you need to make sure you have sufficient power to drive your speakers, therefore this event was not setup to test that aspect.



I'm steadily growing on this bolded part. Power power power... more power... cleaner output. I'm beginning to wonder if 125w all channels driven if that really should be like 400w each channel that the Emotiva XPR-5 can deliver.

I can literally sell my Krell and buy a new Emotiva XPR-5 for the same price. Hmm....
"Sharp ears" Dennis liked two of the amps more than any others... wasn't all that impressed with the Emotiva "in comparison"... however, when he left he was highly considering purchasing an XPA-3 for his system and perhaps later considering one of his favorites. I think this echoes how subtle the differences were... in that even one of the amps that he did not favor "in comparison" as much as the others is still an amp he would have no issues owning and can still make very nice sound for his "sharp ears".
 

·
Plain ole user
Joined
·
11,121 Posts
Hey guys, a few things I'd like to add.

1. Yes, my results could be chalked up to chance.
2. 5 out of 7 is statistically significant and should not be ignored.
3. I admitted to fatigue at toward the end if the testing.
4. I did not start to miss until the end of the testing. My last few pairing evaluations took considerably more time due to this fatigue.
5. There is only so much time in the day and the group dedicated DAYS to this test, so we did the best we could with the time we had.
6. I feel that I could repeat this test and expect a similar outcome.
7. Each person used different, non standard methods to evaluate the pairings. This was probably the biggest deviation from control in the entire evaluation effort. I am not certain that a standardized method would be useful as we all hear differently and like different music.
8. Our sighted evaluations had better soundstage and imaging properties than the blinded, due to the bulky (but necessary) shrouding used to hide the amplifiers from view.
9. Audible differences in amplifiers are generally very small.
10. I have a favorite amplifier and will reveal that favorite after Leonard has crunched the numbers and posted the results. ;)
Whether 5 of 7 is statistically significant depends on how you define it. By most research standards it would not be, as the probability of getting 5 of 7 if the probability of each choice is .5 would be about 84%. That means that there is a 16% probability of it being by chance. Most would consider 6 of 7 statistically significant, where the probability of it happening by chance is down around 5%.

I did not find that the imaging suffered in the blind tests. My big issue with the blind testing was time and confusion about trying to recall what X sounded like.

You have to consider our overall results, however, for 28 trials, to reach a 95% certainty we would need to be right 18 times. I think we could easily do that with more time and not restricting X for such a limited listening time and fewer amps.
 

·
Plain ole user
Joined
·
11,121 Posts
I think it is curious that even though we felt that we could hear differences in some comparisons, everyone came away convinced that the differences were so small, if real, that we would all opt for the cheapest amp that had the power we need.

I will be publishing the comments on individual amp impressions in the context of the comparisons made soon.
 

·
Plain ole user
Joined
·
11,121 Posts
One thing for sure... this was a major undertaking trying to accomplish all that you group has done.

Major Kuddos!
Indeed. It was a large investment in time and money, the latter more for Sonnie and the guys who travelled farther. The experience of working with this group is well worth it, however. We always have enormous fun and learn something, even if it is exhausting.
 

·
Registered
Joined
·
1,295 Posts
I clipped my X5200 with the Ultras. Perhaps I was listening at louder levels than 105dB... not sure. I plugged my Behringer EP2500 in the loop and there were no issues... problem solved. I wanted a better looking amp and got a really really good deal on a Parasound HALO A31, so I purchased it.

Nice amp! The X5200 is rated around 120w to 5 channel driven so for you to tell me you were clipping tells me the power requirements of the Ultras I got from you. I may end up looking for something with more power behind it as a "just in case" scenario


Not sure where you got that... the Denon was well received. We did not attempt to push it to the limits. I don't think any of us have ever doubted that you can overdrive an amp and that you need to make sure you have sufficient power to drive your speakers, therefore this event was not setup to test that aspect.

Understood I was speaking out of the side of my head.
Notes in red.

You guys really build some suspense making us wait for the end results lol
 

·
Registered
Joined
·
1,295 Posts
Indeed. It was a large investment in time and money, the latter more for Sonnie and the guys who travelled farther. The experience of working with this group is well worth it, however. We always have enormous fun and learn something, even if it is exhausting.
Next time send an invite to me as the official photographer (my main passion)

:)
 

·
Banned
Joined
·
22,577 Posts
Each person used different, non standard methods to evaluate the pairings. This was probably the biggest deviation from control in the entire evaluation effort. I am not certain that a standardized method would be useful as we all hear differently and like different music.
Absolutely... each person needs their own set of evaluation music and methods of comparing.

What I do think we need to add next time is having more repetitive ABX comparisons between the same two amps, which Leonard suggested. This will eliminate any suggestion of chance... and about the only way to verify that it is not chance. There is no doubt there needs to be multiple blind rounds to eliminate chance, but we just didn't have time. We know subjectively you guys heard differences... so no real reason to do that next time. Next time it can all be blind.

I think our next gathering, if we can make it happen, we'll have 3-4 speaker reviews and only 2 amps for repetitive ABX'ing. Frank also said the popping noise during switching was not normal and I am sending it back to him for repair/replacement. That way next time someone can swap amps with the lights off and the listener can determine if amps were switched. Makes it more interesting.

I know we may not be able to get you back over here... if you are working, but maybe we can find someone who feels like they are seasoned in hearing differences to attend and and let them take a swing at it. We might throw in one set of cable comparisons too.

It may also be good to have those not testing to go outside the room while others test. During the blind testing you guys only spent 15-20 minutes on each amp comparison and that was spread out over the course of the day/night. So hearing the other music while others were listening apparently played a role in fatigue. Otherwise, I wouldn't think a couple of hours of listening over a 12 hour day should be that fatiguing.
 

·
Registered
Joined
·
3,697 Posts
I like the idea of repeatability, and agree that leaving the room can help offset fatigue.

My first few evaluations went quickly, I was done in just a few minutes. Sitting and listening to others do their evals was fatiguing, and toward the end of the day, my evals were 3 to 4 times longer and my notes reflect my uncertainty at this point.

I feel confident that I could have picked up at least one more correct answer if I had not felt so weary toward the end. Those last few were VERY difficult.
 

·
Registered
Joined
·
3,697 Posts
Whether 5 of 7 is statistically significant depends on how you define it. By most research standards it would not be, as the probability of getting 5 of 7 if the probability of each choice is .5 would be about 84%. That means that there is a 16% probability of it being by chance. Most would consider 6 of 7 statistically significant, where the probability of it happening by chance is down around 5%.

I did not find that the imaging suffered in the blind tests. My big issue with the blind testing was time and confusion about trying to recall what X sounded like.

You have to consider our overall results, however, for 28 trials, to reach a 95% certainty we would need to be right 18 times. I think we could easily do that with more time and not restricting X for such a limited listening time and fewer amps.
I'm not sure, but I think 80% is considered significant in a subjective endeavor. I'll dig around for more info when I return home. Agreed that repeatability would make the data more robust.

If we had more amps, it would likely have dinged my score down considerably. Less amps, I might have scored 100%. :D

Remembering X was easy for me until the end. The next test will build on this one and I'm confident the group will have better data. I do hope I can attend, this was a blast and I liked working with such an intelligent bunch.
 

·
Banned
Joined
·
4,838 Posts
Discussion Starter #72
Seems there is a decent amount of evidence to support the theory that differences between amps can be heard. The evidence also suggests that there are select few who can detect the differences by ear, and under very specific conditions. Which means... the debate will continue!
Well put. Under a very carefully chosen set of conditions, I felt quite certain, for instance, that the sounds with one of those amps had more clean, open space around them than from the amp AB'ed against in sighted AB testing. If you make my getting supper tonight dependent on being able to pick that amp out in an ABX test or any other test, or even a repeat of the same test on another day / different room / feeling tired / insert variable here, I am likely to go to bed a hungry boy.

What can I add that hasn't already been said?
  • Family/visitors impressed with picture and/or sound... CHECK!
  • Family/visitors unwilling to invest in quality components... CHECK!
  • Family/visitors put off by system complexity and calibration... CHECK!
But how about:
  • Visitors/family who don't watch/listen as if in movie ther or music hall?
  • Visitors/family who like to watch movies in daylight or lights on?
In other words, some people don't treat the performance as a primary activity. They repeatedly get up and move around, make annoying noises, narrate, etc., etc, etc. I suppose that's okay with certain types of performances like sports, but it can drive you up the wall if you're the type that likes to suspend disbelief and immerse yourself in the presentation.

To relate this back to the amplifier comparison, the participants recognized the difference between background/distracted listening and focused evaluation. And oh, how those distractions satisfied! Yummy food, and pleasantly rewarding company! :TT
I appreciate the feedback - from a number of you - to the question. It leads into some decisions that were made concerning our Audyssey XT32 / Dirac Live comparison. Which, by the way DID happen...
  • In spite of technical issues - these will be outlined in the report, because they are pertinent to those who might be making a choice between them.
  • In a different way than originally planned. Par for the weekend.
  • Choosing a very particular set of test conditions for a very particular set of reasons (cough, ahem, nudge, wink - see aforementioned discussion).
  • With great attention paid toward making it an apples-to-apples comparison.
  • With - sadly - a limited number of evaluator ears - sorry guys, we really tried, BELIEVE me we tried.
  • With fairly conclusive results, in my opinion (how is that for confidence?).
Lots of writing to do, but this report is HIGH priority, it will be separate from the miniDSP nanoAVR DL review, due this month - ooooohhhh, did I say that out loud?
 

·
Banned
Joined
·
4,838 Posts
Discussion Starter #73
Well one of the main reasons why I was curious of this testing was this very fact... While I am leaning more toward the fact that amps make little audible difference when properly levele matched I do feel after reading and NOW agree that the biggest differences in amps that are audible are when they are driven loud are are driving into distortion.

I've read that and based on the results of these tests and some other publications I really do feel like amps make a minimal amount of differences IF driven into non distorted levels. This is solid state vs. solid state of course.. I do think tube amps sound different.

One of the only reasons I have a separate is the fact I got it for a decent price and that was that. After checking the actual test data my Krell can drive all channels into 108 watts at 8 ohms at .1% distortion and 136w at 1%... this is the actual test data of driving ALL channels at the same time.

Even checking current AVRs it takes a 2,000+ dollar AVR (typically) to be able to produce the same specs. My X4000 driving 5-6 channels only produces some 68 watts at 1% which basically means I can play louder and cleaner. than my AVR alone. I spent 2450 total on my AVR and amp which yes that could of bought me a high end AVR....

only issue is a high end AVR would be 1/4 the price in three years where my Krell value will hold true since it's market keeps the pricing current.

Now... something like the Outlaw 5 channel amp would be on my radar to test.... considering it's rated 200w each channel at .1% which gives me some 90w more headroom. Would love to hear that when playing loud and seeing if there are any audible differences.
I like that you have outlined a fairly specific set of factors that led to your choice. Someone else would use their own set of factors for their own reasons. Others might argue the validity of those factors. Bottom line, you did what made sense to you and you are happy. Excellent.

LOL yup this debate will never die

I do think it does show though that the differences are subtle at best. In normal listening conditions it probably would be even less noticeable.
I certainly agree. We drove Sonnie's ESLs pretty hard - during fun time - with a smaller amp and heard that strain, and some clear breakup - both pretty unmistakable. Other than that, subtle is the key word.
 

·
Banned
Joined
·
4,838 Posts
Discussion Starter #74
I doubt that, BY ITSELF, dropping in a toroidal transformer will transport any amp into "higher-end" territory. Aside from trendy parts replacement such as toroids or fast recovery diodes, it's a particular power supply's DESIGN that helps account for any possible audible differences. For example, a fancy transformer won't make up for poor ground return paths in the signal chain.

How concerned is our review panel with, say, circuit topology, premium parts, and signal transfer of WBT vs Cardas vs plastic binding posts? Perhaps they'll become curious as they endeavour to explain slight differences. But I doubt they'll delve into a full blown, deep-dive exploration.
Would that we had the time to do so. The amp choices were made with many such factors in mind, but detailed analysis of the kind of factors listed, as I am sure all can appreciate, was simply beyond our scope. It would have been SO interesting.

Only One, and that is kind of sad really.
Indeed, it is no much fun to share, and hard to find others who truly care.

Phrases like "normal listening conditions" are filled with assumptions. Normal listening conditions for someone who cares are very different than your average consumer. This is what Wayne was getting at.
Precisely. "Typical" for us (including all present, probably) is "crazy / nuts / ridiculous" to most, And when we get serious, look out. This relates to the entire weekend and to numerous choices wes made along the way, and to our purpose for it and to our upcoming detailed results. Our own assumptions about listening were challenged many times over the weekend.
 

·
Premium Member
Joined
·
629 Posts
Some (non-serious) observations ...

1. Are you guys insane? That's some serious work for a single weekend!
2. Did anyone think we needed even more reasons for Dennis (Tesseract) to be cocky?
3. This amp shootout, while not necessarily intending to, somewhat showed why higher efficiency speakers are a good thing.
4. This amp shootout makes me want to get a pair of Martin Logans or Magnepans.
5. Thanks to everyone for a really great read already, and looking forward to reading more.
 

·
Registered
Joined
·
1,784 Posts
Some (non-serious) observations ...

1. Are you guys insane? That's some serious work for a single weekend!
2. Did anyone think we needed even more reasons for Dennis (Tesseract) to be cocky?
3. This amp shootout, while not necessarily intending to, somewhat showed why higher efficiency speakers are a good thing.
4. This amp shootout makes me want to get a pair of Martin Logans or Magnepans.
5. Thanks to everyone for a really great read already, and looking forward to reading more.
Some of these points ring very true indeed. Never the less, I think point three misses the point...so to speak. We need to acquire our amplification based upon the speakers we have in our rooms. While higher efficiency speakers can help if we just cannot obtain sufficient power to drive lesser efficient or difficult loads. Frankly even highly efficient speakers can benefit from serious power behind the cables. Try watching Fury or the depth charge scene in U571 for some extreme examples of needing power and an incredible reserve.
 

·
Registered
Joined
·
1,295 Posts
Well this has def opened my eyes and I'm not so hung up on Krell like I once was. Just happy that I have enough juice to power what I got at levels that I like.
 

·
Registered
Joined
·
1,295 Posts
Fury or the depth charge scene in U571 for some extreme examples of needing power and an incredible reserve.
I love Fury and although it doesn't hit really low... I think the bass is executed perfect and portrays realistic scenes.

The SVS Ultras and my Krell handled it nicely and at 0db on the reciever after audyssey checks was hitting 105db with the REW SPL meter (not sure at what frequencies). Not sure if this is reference or not but it was way louder than I liked the scenes. I like around -6db for the tank scenes.
 

·
Registered
Joined
·
1,784 Posts
I love Fury and although it doesn't hit really low... I think the bass is executed perfect and portrays realistic scenes.

The SVS Ultras and my Krell handled it nicely and at 0db on the reciever after audyssey checks was hitting 105db with the REW SPL meter (not sure at what frequencies). Not sure if this is reference or not but it was way louder than I liked the scenes. I like around -6db for the tank scenes.
I am glad you love the movie soundtrack, so do I. But in this case I am not speaking to the "low" in the sound but the impact supplied by the main speakers. This is where the impact of the tank shelling comes from and it will draw an awful lot of power to take command of the woofers and force them to do the right thing. I am sure the guts of a power supple would be severely taxed in these scenes.
This will also put on display many of the short comings of some amps in that they may not have power reserves to keep up.
 
61 - 80 of 251 Posts
Top