A listening test of two power amps

I’m not aiming to deride your efforts, OP, just sharing objectively:

by limiting the samples to 2 and stating each sample is from a different amp, you’ve set the stage for expectation bias in responses.

Repeated measures can make for a challenging experimental design online.

 

Which recording produces the most realistic rendering determined by what ? Not the device that rendered it ? but by  ?? I am easily confused not being rude but I am in need of little more guidance in order to participate please. You have provided a recording engineer's stats and it is obvious you know what they mean. I don't.  I am very impressed with your knowledge and your  detailed test. 

What is the "real instrument" reference? Do you have an orchestra or maybe a jazz combo around? Maybe you live in an apartment above Carnegie Hall. In any case it's personal taste that drives the "reference" myth as all recorded music is an illusion filtered through our addled brains.

@surdo  you have to measure voltage at the outputs using test tones.

I didn’t realise that this would be such a contentious post! :-) Starting with the most recent:

"What is the "real instrument" reference? Do you have an orchestra or maybe a jazz combo around? Maybe you live in an apartment above Carnegie Hall. In any case it’s personal taste that drives the "reference" myth as all recorded music is an illusion filtered through our addled brains."

Yes, the reference is the sound of real unamplified musical instruments, played by musicians. In my case, I know well the sound of a piano. I played violin (still play a bit) and have been around quite a few double basses. I also played drums for a number of years and I still play other instruments. And actually, in the recordings, it’s the snare drum and the cymbals that have helped me detect realism. So those are my references. Anyone else that’s heard an instrument played unamplified can use that as a reference too. When you hear a recording, it might (and often does) sound too bright, for example, and that might be the fault of the stereo that’s playing back the sound or the way the instrument was recorded (with mics) or equalised. And yes, that’s a big issued when you’re trying to compare gear - one piece of equipment might be rendering the rotten recording perfectly, when another smooths out the rough edges. But the listener can tell whether or not the sound appears "natural" through his or her experience of listening to real instruments. I’m sure most people on this forum have listened to instruments played with no amplification.

I don’t think it has anything to do with personal taste. A real instrument sounds like a real instrument.

"Which recording produces the most realistic rendering determined by what ? Not the device that rendered it ? but by ?? I am easily confused not being rude but I am in need of little more guidance in order to participate please. You have provided a recording engineer’s stats and it is obvious you know what they mean."

As above, but re, the stats: I just put those there because someone mentioned that my method of level matching wouldn’t work. I don’t doubt that there’s a better way, but I printed the stats to show that my recordings were fairly evenly matched, at the least with any difference being imperceptible, I think. The peak of any audio file is the digital sample of the file with the greatest amplitude and the highest sample amplitude possible in a digital system is 0 dB, when using the logarithmic decibel scale of intensity. Other values are negative and the more negative the value, the less amplitude it has. The trouble with these peaks is that they occur rapidly, so fast that our ears can fail to perceive their intensity. RMS stands for root mean square and this is a type of average of adjacent values (so those amplitude values that occur around the same time). These "RMS" values relate much more closely to our perception of "loudness" (the human perception of the acoustic property, intensity). So since the two recordings had RMS peak values -16.77 dB and -16.72 dB (0.05 dB "louder"), the difference is so low, that I believe the loudness of the two recording is reasonably well matched.

"I’m not aiming to deride your efforts, OP, just sharing objectively: by limiting the samples to 2 and stating each sample is from a different amp, you’ve set the stage for expectation bias in responses. Repeated measures can make for a challenging experimental design online."

I agree. But that’s all I had time to do and I didn’t think anyone here would have time or inclination to listen to more, let alone 2 recordings;

"Much a do about nothing IMHO...sorry."

Don’t feel bad about it, humble one. That’s ok.

"What an incredible amount of trouble to go to to make a comparison between two amplifiers that does not necessarily align with real world sq and whether or not one sounds better to the listener or not."

The test and editing only took an hour. Writing and responding here is taking longer. Although I’m enjoying it.

"I would venture to say few here have the desire to dive into the minutiae the way you seem to enjoy. So which amp sounds better to you? Don’t over analyze it..."

That’s true, but it would surprise me that people don’t put this effort (and concentration) into their own gear selections and configurations, especially with such large sums of money involved. I’ll get to my opinion soon.

"I can’t read the flac files and don’t care to load the software to enable it. Put them on YouTube for a bigger audience."

If you’d like me to put a CD format wav file online, please let me know.

"Tracks actually loaded easily via copy/paste into a url search field on my Mac. Listening through Sennheiser headphones and a very decent dongle Dac. e.flac seems to have more body, realism relative to the room of the performance. t.flac gets more detail, but seems a bit colder in tonality. Level match seems close enough to render the important qualities to me? But maybe try a couple more…"

Thanks for listening @riccitone! And since we have a listener, I’ll reveal the amps:

A pair of Quad 303 amps used to bi-amp the monitors and a Sunfire Signature 600 (early version) bi-wiring the speakers with the "voltage source" speaker outputs attached to the main driver and the "current source" outs connected to the tweeter.

What I did to listen, was to load the two files into two VLC media players. I have a way on my computer that i can shuffle the two players, with one on top of the other, so that I don’t know which is on top after shuffling. I then separate them, so they can be played, and conceal the title bar to make them anonymous until satisfied enough to check. I did this a whole lot of times.

My conclusions were very similar to yours and the first thing that struck me was the full body-ness of e.flac. I also paid a lot of attention to the snare drum in the opening passage and that appeared to have the airiness of a real drum in e.flac despite t,flac sounding a tad cooler. I also found the bass a little clearer in t.flac and I think the piano masks it more in e.flac. I have to admit it’s really difficult though. I think both sound good. And after some repetitions of listening and revealing the file name, I didn’t always reach the same conclusion. But mostly did.

Which amp corresponds to which file?

e.flac is the Quads
t.flac is the Sunfire

Without going through the rigmarole of setting up a mic and listening to the recording, I think I hear the same tonal differences and instrument separations when sitting in front of the system, listening in stereo. I think there, the Sunfire has the advantage of slightly better imaging and I suspect that is due to its slightly cooler sound and with the higher frequencies (usually easier to locate) taking predominance. But the thing with the snare (and cymbals) sounding more real and airy on the Quad still confuses me. i.e. why wouldn’t this help with imaging? Perhaps my two "identical" 303s aren’t so identical, there might be a mismatch. I have tried using just one of course. It didn’t sound so dynamic and I didn’t at the time compare it with the Sunfire.

"GREAT version of U.M.M.G btw 👍🏼👍🏼👍🏼"

Well spotted! I didn’t give the full name of the track and the musicians because I think there might be copyright issues. But it’s a Brazilian trio residing in New York. Recorded two years ago and released on vinyl last year. The pianist was 83 when the recording was made and he was one of the founders of the Brazilian jazz trio movement in the sixties. A cult figure. Pioneer of samba-funk too.

I think there have been other replies since I started writing this message.