Good morning, after some careful thought, I have decided to do a round robin style T-amp test.
Please see the poll for choices to add to the Gizmo and Sonic Impact Super-T.
For this test, we will use a pair of high quality bookshelf speakers - I have Dana 630's, Ascend 170 SE's, NHT Model 2's, and could probably get a pair of X-LS, too.
It is not that simple. What speakers? What listening distance? What volume level? Sub or no sub? What type of music? CD, mp3 or other? What DAC/devices upstream?
What does best mean? Do you just want to test to see if you can even tell the difference? Do you want each person to pick a favorite? Do you want to rate them based on a number of factors? What factors?
Really the goal should be which is suitable for a budget 2ch system and the answer is all of them because I know (minus the pop pulse) that they all have a certain degree of very good sound quality...well, actually I have not heard the Gizmo either, but several people said it sounded pretty good and most of the time at a GTG if something is no good they either dont say anything or say "I didnt get enough time to get an impression"...yeah, that means its bad.
Trying to determine which is best is very subjective. I think a goal of determining if there is any significant differences in sound quality would be an adequate goal. Many conclusions can be derived from such a hypothesis. ie. $100 amp has no discernable sound quality differences from a $235 amp. But again, these are only my thoughts...
You are still totally missing the important point of under what conditions.
If you are setting up a budget system for your basement game room where you plan to power a pair of 86db sensitive large bookshelf speakers to an average of 85-95db, is it at all relevant that there was no discernable difference between the amps when played on 92 db sensitive desktop speakers at an average level of 75 db and a listening distance of .5 meters?
The speakers the amp is driving, the volume level and the distance will have a tremendous impact on what amp is "best" or if you can even tell the difference. What music, including the quality of the source is important as well. For the test to give useful, relevant results, it needs to accurately represent the way you intend to use the product in all of the important factors. If you browse the Gizmo threads you will find quite a variety of intended uses for this neat little bugger, so if we are going to test it we are not going to be able to test all scenarios.
Maybe it should be a combination blind and "clinical" test.
We know that the Pop-Pulse and Gizmo should KILL a trends or super-t for max output...but shouldn't we know an approx. max level we can attain? I doth believe so.
Maybe they should also be set up in multiple scenarios as well...
I don't know the answer but just asking 3 guys to guess which he likes the best doesnt seem like it will accomplish much.
You are still totally missing the important point of under what conditions.
If you are setting up a budget system for your basement game room where you plan to power a pair of 86db sensitive large bookshelf speakers to an average of 85-95db, is it at all relevant that there was no discernable difference between the amps when played on 92 db sensitive desktop speakers at an average level of 75 db and a listening distance of .5 meters?
The speakers the amp is driving, the volume level and the distance will have a tremendous impact on what amp is "best" or if you can even tell the difference. What music, including the quality of the source is important as well. For the test to give useful, relevant results, it needs to accurately represent the way you intend to use the product in all of the important factors. If you browse the Gizmo threads you will find quite a variety of intended uses for this neat little bugger, so if we are going to test it we are not going to be able to test all scenarios.
I was typing a long response, but said forget it.. If this was directed at me, i think you may be assuming quite a bit. I just stated a GENERAL hypothesis from which, as a community, can be narrowed down to a specific one (ie. given the highest common denominator of all amps using this as the limiting factor during testing, at a seating position of 1m, volumes in 3 levels, fed by a blah blah blah...) One could not test for all possible situations, if there is a budget or a time constraint. But you can say, within the test parameters we found no discernible difference in sound quality from a to b. People can accept or reject these findings, and do what they want with them. There will always be people disagreeing with the testing procedures, and to them i say do your own test...
But alas, i know nothing so i will stay out of this discussion.
There is no such thing as "best" until the purpose has been well defined. Whats the best used car? A geo metro, a mustang or a chevy pickup? Well, what is important to you, milieage, turning it into a custom drag racer, or hauling lawn maintenance equipment?
If you see the discussion in the amps 101 the thread, the problem is by tweaking the parameters of the test I can all but insure the outcome I want. If the test is to see if you can tell the difference, I can design a test where you can not. I can also design a test where it is easy to tell.
You just want to know which one sounds best? I could set it up with a pair of Ref-1's with a 3.5 ohm impedance and select the material seating distance and volume level such that the Gizmo does not clip but most of the others do. You might scream that is no fair, but if someone is really going to use 3.5 ohm speakers at those volume levels it would most certainly be a fair test and an important one at that.
A LOT of people don't want to do too much research or learn all the details themselves which is fine, in the end the hobby is about listening to music. OTOH, they still want to know "what is best" either in a ranking or a simple price for performance number or an easy to compare spec. It just doesn't work that way for amps, subs, speakers or just about anything in audio. You would not go into your grocery store and ask the produce clerk which is the best vegtable, or which one is maximizes your bang for the buck. You need to have a good idea of the intended use before you make any attempt to select which vegie or which amp or which sub is going to be "best".
As is pretty easy to understand from reading the responses here, deciding how to construct a blind test is not a simple task.
I know some people got irritated with me for some comments I made about T-amps - and amps in general - earlier in some threads here, including this one.
Since the late 70's, 30 years ago, I have taken and/or set up 100's of blind tests. It does require a lot of preparation, and also thought, to do one properly.
So ... perhaps everyone will indulge me while I lay out what I think the hypothesis of this test should be, and how to set about proving - or disproving it.
The hypothesis: When operating within their rated output specifications, Some amps sound better than others. Many listeners claim to hear an immediate difference when switching from one amp to another.
The test: We will take a small panel of listeners and no more than 4 amps. These amps will be level matched to within 0.1 dB using a 1000 Hz sinewave. The panel of listeners will get to listen to each amplifier for a period of 2 minutes each, and will then vote on the sound quality of each amp.
This will be repeated, with the amps being played in a random order each time, for a total of 10 rounds of 4 x 2 minutes.
Speakers will be a pair of high quality bookshelf speakers of reasonable efficiency.
Sound pressure levels will be set to make sure none of the amps clips during the 10 rounds.
If the listener cannot hear a difference, he has 2 choices, guess - and hope he doesn't get "caught", which will be unlikely, given the odds over a preiod of this many trials.
Or - he will vote each amp the same.
If the listener DOES hear a difference, it will be consistent over the 10 trial periods.
Ok guys - that is my take on this. Please, feel free to chime in ... :thumbsup:
A test that is just 2 chanel, with easy to drive speakers and volumes intentionally held below the smallest amps clipping might seem to be a good choice. BUT, such a test ignores the Gizmo's sub out feature. It ignores the Gizmos 4 ohm capability. It ignores the Gizmo's 25 watts or the benefits of offloading bass duties to a powered sub.
Hmmm, how about we test a couple of pickup trucks by driving them off road. Since most of the test trucks are two wheel drive, we will leave the 4wd truck or trucks in their 2h mode to keep things fair. Sounds silly doesn't it? But then again, if you always drive on paved roads doesn't it sound silly to be testing the trucks offroad to give the 4wd versions an advantage?
In the end, I think the limited load 2 chanel "test" probably will be the least controversial and maybe we can get an idea if within their limits all of the amps sound generally if not completely the same.
You could then increase the load or SPL until you can hear the differences and maybe define those points. I think a 2.1 comparison with the amps that can be used with a sub, either with a sub out or the subs high level inputs would be even more usefull to many people, and if some of the amps can not be used with subs in either manner, it should be noted in the results since that could be a huge factor to a potential buyer. That is now 4 tests. Within their limits, pushed to the limits in 2.0 and within the limits and pushed to the limits 2.1.
The hypothesis: When operating within their rated output specifications, Some amps sound better than others. Many listeners claim to hear an immediate difference when switching from one amp to another.
I think the better and easier way to test this is to ask people to listen to a pair of amps and vote same or different. If the theory is they sound "different" directly test that.
Pick just two amps for each run and either play AA AB BA or BB. You could then track how many times people think they hear a difference when there is none or can not hear one when there is.
To make the ordering random I would have the switcher flip two coins to set the amps for each trial. Heads is A tails is B, the nickle is the first amp played, the quarter the second.
Given the low wattage of these amps I would select fairly efficient speakers and quality recordings but with limited dynamic range (peaks) so the average volume levels are relatively high to make it easy for a group setting to hear.
mfine, again, i dont know if you are referring to me, but did not state better in my post, so i am unsure...
Craig i think that is a more than acceptable test...
mfine, this test does ignore the sub out etc... BUT it does compare to the sound quality up to the limitations of the smallest amp. To me this is the point of THIS particular test. is there a significant difference in sound quality at the specified spl level of all the amps, and (presumably tested at lower spl's as well). You can have a disclaimer that this does not test anything in excess of this spl level...
regarding the 4wd analogy, i think it is fair to test it in 2wd, as long as you state you are testing its 2wd capabilities over it's 4wd. You are outlining the limitations of the actual test.
Testing say the geo vs ferrari, which drives better from 0-40mph, is quite significant. There is quite a diff between the two, even though you limit it to the capabilities of the geo, it still provides significant data, ie. city driving. One has better handling at this speed, the ferrari is difficult to drive at this speed due to having to keep the revs in the upper band. etc...
I think Craig outlines a perfectly valid blind test but to me the results won't matter much at all because I don't listen that way. I like the direction Bill seems to be leaning. Give the amps a test drive in various conditions.
Nearfield computer-desk kind of set up seems very appropriate, with moderate volume, as would a larger room to simulate someone using in bedroom or maybe as primary two channel, where you'd certainly want to push the SPL.
I'd probably want to swap two different speakers into the test, something relatively efficient (88+dB) and something below 85dB, that is maybe considered harder to drive relative to impedance curve.
I'd like a few types of music to be evaluated - classical/orchestral, jazz w/female vocal, and some hard rock cover it for me. Maybe more or different genres are more approprioate?
The feedback I'd want is more commentary and less "amp A beats amp B". Try to explain what you hear in each scenario. Tell me what stood out, both good and bad. If a specific difference was significant then tell me, but don't try to force yourself to hear differences that are negligible.
I'm not asking or suggesting that this work be done. It would be very time consuming, although I imagine a lot more fun than a double blind. If something like it was put together, however, I think it would give potential customers a lot more info than is easily put together today. And they'd be able to logically pick a product for their intended use. Knowing that Gizmo and Trends can't be easily discerned by four guys listening to a bunch of two minutes samples won't help me know what to buy or why to buy it.
If you do not want to test which one is best, then I am not refering to you am I? But, much if what I said was meant as food for thought for everyone.
My biggest fear is that if a test is conducted, the results will be used by potential buyers for whom the test is completely irrelevant. The next fear is the crowd of forum trolls it will attract. Picture a splash of blood and the nasty people from "I am Legend". That movie had the most realistic depiction of Grandarf and company yet to come out of Hollywood and they will be all over whatever we do.
But it would help me with my choice. Lets say that i wanted to buy the trends ta-10, which has a max output of 15w (or whatever it is) at $150, this test shows that at the max output of the trends amp, the gizmo has no discernible difference in sound quality, has an additional 10w, a subout, and is 129.
So to me this test made my decision easy. I got all the trends had to offer with additional power, an optional sub out, and at a cheaper price...
ps. thanks for the clarification mfine, didnt really warrant the attitude, but whatever...
Isn't the blind aspect necessary? If I want/expect the Gizmo etc. to sound "better", then I might subconsciously have a bias towards it.
I don't see the big to-do about a test. Put the amps on some measureable and equal playing field, and turn your back to them while someone else does the switching. And why would anyone criticize the results? If they think there was something left out, they can do their own comparison.
Ahh, but it is not that easy since none of the amps come with power meters. If in your normal listening you will have peaks that push past the rated limits, how each one handles the peaks could be the most important feature and it is not tested.
Lets say you will often get peaks that require 30-35 watts. Perhaps the Gizmo clips hard at 25 watts and makes harsh and painful noises. The trends may softly clip the peaks, reducing their levels but not adding any harsh distortion. Or maybe one of them behaves like a tube amp and adds even order harmonics that sound somewhat warm and pleasant (in some peoples opinions). Is the Gizmo still the better deal?
I know one test will not satisfy everyone's questions, but acts as an indicator. In this situation it is still a better deal, as i sit .5m from my 87db (sensitivity) speakers rarely exceeding 90dbspl.
I understand what you are saying, but you can do that for ANY test that could ever be conducted. You can find a limitation with any test. The only way to bypass these limitations is with an unlimited budget, unlimited time for testing etc...
I am in no way saying these tests will lead to the ultimate amp rating guide. But to me it gives me information i find relevant, and is much more beneficial to lack of info. I dont think any of the test participants will be going public saying gizmo is better than this amp blah blah, i think they will let the test results speak for themselves, allowing you to derive your own opinion on the tests. I know to take tests with a grain of salt, such as statistics. Statistics are taken with goals in mind, BUT they can provide helpful information as long as you review the testing parameters.
I know one test will not satisfy everyone's questions, but acts as an indicator. In this situation it is still a better deal, as i sit .5m from my 87db (sensitivity) speakers rarely exceeding 90dbspl.
So if we conduct a nearfield, within rated limits test you will be satisfied, and if a lot of other potential buyers are looking to similar use (that is how mine will be used as well) that would be a good test to conduct. But, we have now defined the parameters of usage to base the test. That is an important first step.
I am in no way saying these tests will lead to the ultimate amp rating guide.
For every person like you who plans to look at the results and think about what it means for their buying decision, I bet there are 10 more who will say amp XX won or they couldn't tell any difference, and apply it blindly to a totally different scenario.
I expect that Craig is correct. It is VERY hard if not impossible to tell the difference between amps kept well within their limits. Where I may differ from Craig (I really don't know his opinion) is I think many many people push their equipment beyond the limits much more often than they think. When people get a new amp from Emotiva or Outlaw and hook it up to their receivers pre-outs and post about a clear improvement in sound, is it placeebo, does the new amp simply sound better, or were they exceeding the capabilities of ther receivers amp stage and the new amp is more capable. I think it is a healthy mix of 1 and 3. I also think when amps are asked to exceed their limits they do so in ways that sound very different from each other.
Here is what I see as the issue. People are constantly talking about how amps have better soundstaging, how they noticed an immediate improvement when getting a new amp, etc ... etc ... etc ...
If this is the case, a short trial should be fine.
Here is what I see as the issue. People are constantly talking about how amps have better soundstaging, how they noticed an immediate improvement when getting a new amp, etc ... etc ... etc ...
If this is the case, a short trial should be fine.
Why can't we put together an "air meter" and just take measurments on how airy the sound is from amp X compaired to amp Y? We could also use it to test cable treatments, cable risers and clocks.
People are constantly talking about how amps have better soundstaging, how they noticed an immediate improvement when getting a new amp, etc ... etc ... etc ...
How about a low volume (in the limits) test of the Gizmo, one of the trends and your McIntosh? Clearly the Mc has capabilities the cheap little guys do not, but does it image better, have better soundstaging or depth, or have more air? OOOOOOHHHHH I almost forgot my favorite, toe tapping.
I am not proposing this to be some form of "proof" that all amps are identical, but rather that the differences, if any, are VERY slight.
Let's take "Joe", who claims that he knows amp "A" is FAR superior to amp "B". He swapped the amps, and there was a HUGE difference. That is, of course, when he could see the amps.
Under blind tests, and with 100 trials, Joe only picks "A" 50 out of 100 times.
Joe may think differently later ...
Here are some possible outcomes of doing this type of test:
1. The panel consistently picks a particular amp as the best. That would be pretty rare, and thus pretty compelling.
2. The panel cannot discern between the amps. We could then reasonably state that paying more attention to speakers, placement and possibly the room makes more sense, true ?
For every person like you who plans to look at the results and think about what it means for their buying decision, I bet there are 10 more who will say amp XX won or they couldn't tell any difference, and apply it blindly to a totally different scenario.
With this i wholeheartedly agree. I know this to be very true. People using these tests/statistics as fact, but not knowing the underlying nature of these tests. Reminds me of Da Vinci's code. How Dan Brown based his whole book using another book as a reference, stating how it was all factual. Then the author of the underlying book came out to the public stating that his own work was fiction
I am willing to wager though that the majority of people buying amps such as the trend, and gizmo, have a higher probability (than the general public) of knowing how to keep these amps within their limits. Reason i draw this conclusion is that, how many people in the general public would believe you can run a 300w speaker off 15 watts, :nervous: Does it mean people wont push it past their limits, of course not. So in this, mfine, i do completely agree (regarding how they respond to being pushed beyond their limits).
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