I understand my ears, ie I understand the distortions and more so the noises inherent in systems, this is the key.
I listen deep into the recording and listen to the nature of the embedded noises, and then listen to/listen for the PB system intrinsic noise, especially the excess noise excited by the program content.
I am able to change the level and nature of the excess noise on the fly, and then pull back and listen to the overall resultant.
Excess noise is an elephant in the room, and probably passed over in many BLT's.
BLT is a function of knowing what to listen for...the 'blind' will of course return null results.
BLT's are probably good for testing how well 'joe public' can discriminate gross differences, but very fine differences will get through.
Dan.
All clear now, the cable is long and some of the very few electrons do not make it to the speaker.
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So what is the mechanism by which not peeking hides the fine differences ALL else being equal? Please don't play the ABX card any truly blind protocol is fine.
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I realize the absolute values of these graphs are not important, but I am curious: are the loudspeaker impedance plots shifted by the same amount as the resistor plots?
Ed I have to say that while it's been a very long time since I was in a physics lab, if this was a lab report I would give you a D- at best, likely a flat-out F. It is possible that you measured something meaningful, and did it well, but it is impossible to tell from what you gave us. I could not tell what you measured, nor how, nor why, nor what your results were, nor what any of it meant. I'm still very unclear about a lot of it. I may be a bit dense, and for that I apologize, but what you presented here was a confused jumble, and I obviously was not the only one who could not understand what you were doing nor why you were doing it.
Now I finally understand that the blue horizontal lines represented derived impedance values for resistors in your test fixture. I'm still not sure why you left them in the graph with the speaker impedance plots. I assume it was as a calibration reference, but then the values don't match the scale so what use is that?
It would be much more interesting to see how and why you developed your Zobel. I understand that you may want to play those cards close to your chest, but then why show us anything? And if you don't tell us what you are measuring, or how, or why, then why would we be interested in your result? "I measured something and got this graph. Please disregard the values."
Unfamiliar room, system and music, and limited repetitions.
I stated how I do my own BLT's (not sure which thread) and am now getting 100% score, BUT that is with familiar room, music and system, and unlimited repetitions........and learned/practiced listening skills.
Dan.
I found similar results can be had only with familiar system and a lot LOT of repeated back and forth. Combined with correlating many T&M with listening.
Some times it helps to have someone point out what they hear so you can zoom in on it....... Kavi Alexander had modules from a recorder sent to me because one had a noise in it. I could not hear any noise even with headphones on. Over the telephone he described the sound and told me to listen 'deeper' etc etc. I finally hear it! and then I could hear it every time I listened to the modules.... just like he did. Then I proceeded to remove the noise.... BTW - I had measured for noise and found nothing... it was a tone buried within the noise.
But I guess that doesnt count because it is a form of peeking???? I think it does count.
Another time I spend a whole day with 2 others..... we listened to just a couple caps added inline with signal...... we must have spend 6-8 hours going back and forth on one or two musical passages comparing until it was down to one preffered and the 3 of us all had heard it the same quality and liked the same cap dielectric and plate combo. We had not set a time limit, either.
It takes hard, careful, deep listening and sometimes experience or training and it is then usually subtle but differences are there and describable. After all that work, it becomes easier for that sound to be heard.... like with Kavi's subtle noise issue.
THx-RNMarsh
Some times it helps to have someone point out what they hear so you can zoom in on it....... Kavi Alexander had modules from a recorder sent to me because one had a noise in it. I could not hear any noise even with headphones on. Over the telephone he described the sound and told me to listen 'deeper' etc etc. I finally hear it! and then I could hear it every time I listened to the modules.... just like he did. Then I proceeded to remove the noise.... BTW - I had measured for noise and found nothing... it was a tone buried within the noise.
But I guess that doesnt count because it is a form of peeking???? I think it does count.
Another time I spend a whole day with 2 others..... we listened to just a couple caps added inline with signal...... we must have spend 6-8 hours going back and forth on one or two musical passages comparing until it was down to one preffered and the 3 of us all had heard it the same quality and liked the same cap dielectric and plate combo. We had not set a time limit, either.
It takes hard, careful, deep listening and sometimes experience or training and it is then usually subtle but differences are there and describable. After all that work, it becomes easier for that sound to be heard.... like with Kavi's subtle noise issue.
THx-RNMarsh
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Wow, I am truly impressed. That's at least three things you are able to distinguish: noise in the recording, noise in your system that is not in the recording, and noise in your system that is not in the recording but is caused by the recording (one assumes some of it is caused by the noise in the recording, etc.). I know I am sounding sarcastic but I am truly impressed if you can actually do that. I could not do any of that while listening to music, all I hear is music. I am reminded of another contributor here who referred to "fatigue" as if finding playback gear that isn't fatiguing is the sine qua non. I wonder what kind of music he listens to that causes such ennui. I have never felt fatigue while listening to music, live or recorded. I listen to music to recover from fatigue.
Even more impressive. I guess if you can do that then your worries are over, maybe you can listen to the music when you have finished tailoring the noise.
But the claims of you would have to be deaf persist. Either these things are subtle or they are not. When Earl Geddes (he's not the only one) an audio professional of some repute says any competently designed amplifier sounds the same when used within it's limits I don't simply discount his input.
I design mostly like Max H. Listen, listen, listen. It helps to have been on both sides of the microphone. My real path to designing by ear was started when I was working at Alesis as bench tech. I would have a drum machine or digital reverb off to the side and make one change at a time, then audition for a day or so.
After a lot of recording and listening to other peoples' recordings along with much circuit design; one is progressively able to pick out different distortions and noises.
All the T&M stuff is just a fact checker for me.
If you can't work this way then you have to let machines verify musicality for you. Or just cast it off to the reviewers and hope.
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Nez
I don't have the ability to change the scale on the display. Or if I do it is buried somewhere I didn't think of.
I can save a test setup with prior tests. So by keeping my calibration runs they provide a reference.
It is a frequency swept current source. So the magnitude of the impedance is being measured by looking at the voltage across the device under test.
To verify the accuracy precision resistors were also measured. Using 4, 8, 12, 16... Ohm values also automatically gives nice reference levels.
Then in the first test run before the zobel network was built there are three more traces. One is for the woofer, the second the midrange and the third wild trace is the horn loaded compression driver that to me appears to be badly interacting with something in front of it.
I then used my kit of switchable L R & C boxes to build networks that would flatten the impedance curves by simple experiment. Of course for the lower frequency peaks I knew that series RLC network was the right approach and by knowing the frequency could select close to the correct values for astarting point. As the inductors have resistance the amount added to flatten the curve was a bit less than simple math would determine.
It was also required to reduce the inductive HF increase. This is done with a simple RC network. The capacitor is picked to match the frequency at which there was a 3 dB rise. The resistor to match the driver's in band impedance.
The surprise was how well the impedance lowering of the HF system damped the rest of the reflected resonances.
If there is something else I left unclear please let me know. Your contribution is appreciated.
I don't have the ability to change the scale on the display. Or if I do it is buried somewhere I didn't think of.
I can save a test setup with prior tests. So by keeping my calibration runs they provide a reference.
It is a frequency swept current source. So the magnitude of the impedance is being measured by looking at the voltage across the device under test.
To verify the accuracy precision resistors were also measured. Using 4, 8, 12, 16... Ohm values also automatically gives nice reference levels.
Then in the first test run before the zobel network was built there are three more traces. One is for the woofer, the second the midrange and the third wild trace is the horn loaded compression driver that to me appears to be badly interacting with something in front of it.
I then used my kit of switchable L R & C boxes to build networks that would flatten the impedance curves by simple experiment. Of course for the lower frequency peaks I knew that series RLC network was the right approach and by knowing the frequency could select close to the correct values for astarting point. As the inductors have resistance the amount added to flatten the curve was a bit less than simple math would determine.
It was also required to reduce the inductive HF increase. This is done with a simple RC network. The capacitor is picked to match the frequency at which there was a 3 dB rise. The resistor to match the driver's in band impedance.
The surprise was how well the impedance lowering of the HF system damped the rest of the reflected resonances.
If there is something else I left unclear please let me know. Your contribution is appreciated.
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Budget recording studios mostly. The model I usually messed with was the HR16.
https://www.youtube.com/watch?v=G7q-5E28wME
Thanks for the detailed reply. I begin to understand what you were doing. I still have a couple of niggling questions but I will keep them to myself while I think about what you wrote, no doubt they will come clear.
I appreciate you taking the time to spell things out, and I hope I didn't come across as a jerk.
And what is the proper sound of a drum machine might I ask? How can a synthetic sound machine have any absolute set sound quality, that seems counter intuitive. Now if you were listening to recorded voice from a voice you intimately know or say piano from a properly tuned piano I could understand somewhat, but listening to synthetic anything you lose me.
Ah, I see, you were designing the drum machines etc. You will have to forgive me, I used to play the drums, so never think of drum machines in terms of HiFi. 🙂
That's very cool, no disrespect. I wouldn't know where to begin with that.
You mentioned digital reverb as well, I think we can agree that analogue reverb tanks are cantankerous at best, though capable of sounding very good once in a while.
I am intrigued by what some performers can do with digital delay loops (having played with analogue units that contained actual loops of 1/4" tape back in the '70s). KT Tunstall is an excellent example, with her "wee bastard" delay. I am flying to Scotland in late August to see her perform in small venue in a remote Highland location. Saw her 3 years ago in Montreal, and the way she uses that device is remarkable (and I would not call it a gimmick).
if "easy later" then why not ABX with blinding protocol "later" and have a real result that you could crow about rather than leaving it in just another story land
controlled, blind listening doesn't preclude any traiining you need to learn the difference, only applying controls "later", after you have learned to focus, found signals that bring out the difference is fine, recommended even
it only requires the final "money" trials be controlled, blinded and hit statisitics decided in advance
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I'm getting all the responses to the post that started this "listening discussion" and am amazed at the differences of opinion.
I only asked if anyone had anything, good or bad, to say about the Chinese made metcal PS-900. I had no idea that there are so many opinions on listening and that testing was such an issue.
I just like listening to jazz or classical and having fun poking at the snake oil BS sellers.
I only asked if anyone had anything, good or bad, to say about the Chinese made metcal PS-900. I had no idea that there are so many opinions on listening and that testing was such an issue.
I just like listening to jazz or classical and having fun poking at the snake oil BS sellers.
It's pretty simple really. Get a nice looking chassis, some good marketing speak OR a good reputation, and send your product to reviewers. Just sit back and wait for your top notch review, filled with hyperbole, while the actual performance matters very little.
A lot of total garbage has received great reviews and sales as a result.
A lot of total garbage has received great reviews and sales as a result.
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