John Curl's Blowtorch preamplifier part II - Page 2980 - diyAudio
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Old 24th November 2012, 10:08 AM   #29791
Pano is offline Pano  United States
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Originally Posted by john curl View Post
People should just listen up or ignore me. I am beyond convincing someone that I know what I am doing.
Good luck with that, John! This is a public forum where discussion is encouraged.
Perhaps a blog would better fit your needs?
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Old 24th November 2012, 10:32 AM   #29792
Bonsai is offline Bonsai  Taiwan
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Part 2 is nearly 3000 pages long and part 1 was of the same order of magnitude and yet we are no closer to the holy grail.

I for one am not yet convinced . . .
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Old 24th November 2012, 11:14 AM   #29793
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Originally Posted by john curl View Post
People should just listen up or ignore me. I am beyond convincing someone that I know what I am doing.
I think there are quite a few of us who are listening . . . we might just be making less noise.

Personally I'm getting towards the point where I've tried all the stuff that is intellectually obvious so if I want to make further progress with my audio design I have to get into the esoteric stuff
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Old 24th November 2012, 11:25 AM   #29794
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Default 16Hz organ pipe...

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Originally Posted by kgrlee View Post
Using mono subs, as with most HT systems, converts the pleasant trouser flapping particle velocity to unpleasant "pressure in the head" sensations..
Size of the room ? Pressure VS wave.
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Old 24th November 2012, 11:41 AM   #29795
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Mikelm, I am glad that someone is listening. Actually, I learn a lot from others, and some here have put their time and money where their opinions are. More than me, in my old age, and with my apartment.
Still, I can hear small differences in electronics that defy straightforward measurement.
To do this, I use my STAX Lambda Pro headphones with a direct coupled vacuum tube based headphone amp. I recently used this set-up to evaluate a new product for a famous client. The STAX beat out Sennheiser, Grado, Audeze (barely), and Denon headphones priced up to $1000.
AND, I can still hear differences in seemingly almost identical circuits.
This is very useful for me, but I have to admit, that I could hear a lot better, 40 years ago. The STAX headphones make it possible for me to still hear these differences, as these headphones were also the ones that originally showed me what the Bybee Purifiers were all about, and the limitations of Alps pots (even though I still use them, myself, in my less exotic products) for example.
Whatever difference I hear, it is beyond the measurements that I can easily do, and I can measure IM or Harmonic to about 1 part in 1 million, with noise averaging to remove the residual noise, and I can accurately note the whole harmonic spread. I really think that is low enough for THAT sort of test.
Still, there must be SOMETHING that will measure the differences in two line stages (for example) and give me direct evidence of why one sounds better than another. I'm open to serious suggestions.
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Old 24th November 2012, 11:51 AM   #29796
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As a contrast, and I've mentioned it before, this is one of the better captures of a good system working the room well: Manfrotto FIG RIG 595B test video - REY AUDIO RM-7V in KENRICK SOUND showroom - YouTube.
Frank
That's the reason why i run horns at home. Other examples:
audiopavillon enceintes hi-fi francaises hr percus duo de pavillons avant garde de 68cm horn - YouTube
Modern Horn Speakers played Excerpt from The Nutcracker Suite - YouTube
PIONEER EXCLUSIVE model 2402 Special Polished Walnut Sunburst 2 - YouTube
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Old 24th November 2012, 12:22 PM   #29797
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Yes, the dynamics are there, first step taken care of; however, even through the deficiencies of YouTube playback I can hear the next problem that has to be knocked over, the "oversharpness" of the treble, as some may call it. Which is why a lot of people pull back from this sort of replay - it's not a problem with using horns per se but the fact that the easy dynamics exposes more vividly the underlying system distortions ...

Frank
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Old 24th November 2012, 12:23 PM   #29798
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Originally Posted by john curl View Post
Whatever difference I hear, it is beyond the measurements that I can easily do, and I can measure IM or Harmonic to about 1 part in 1 million, with noise averaging to remove the residual noise, and I can accurately note the whole harmonic spread.
I envy you your sophisticated real world measuring equipment.

When designing with the aid of spice I always test fourier up to H20 and I have noticed that if spice predicts that H10 - H20 is around -130db it sounds much better than if spice predicts H10 - H20 is only -100db !

I am very curious to know just how low you can engineer your actual H10 - H20 power amp levels in real life and what you regard as sufficiently low ( beyond which no further improvement can be heard ).

I am current aiming between -125db to -150db in spice. (edit - but I have no idea how this translates in real life )

mike

p.s. Pity I sold my stax phones 30 years ago !

Last edited by mikelm; 24th November 2012 at 12:29 PM.
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Old 24th November 2012, 12:23 PM   #29799
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Still, I can hear small differences in electronics that defy straightforward measurement.
John, seriously, we all do. The important word is "small".
Have-you listened to the links i had provided to recordings of some audio enclosures outputs ? In front of such a disaster, don't you believe we can focus our attention to something else than "sound of cables" ?
Listening "small differences", there is a moment where we invent them.
I run a Rotel RC 850 preamp. (because it has all the commutations i need) I have changed the electronic inside, using current feed-back op amps with a high speed booster able to drive a loudspeaker, and resistance arrays to tune the volume. When it is near impossible to make the difference with a strait wire, what i have to worry more about ?

With all the money saved, comparing with some "high end" products, i can work on the acoustical treatment of my room and my enclosures. And more important than all, buy records.
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Old 24th November 2012, 12:48 PM   #29800
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Originally Posted by fas42 View Post
Yes, the dynamics are there, first step taken care of; however, even through the deficiencies of YouTube playback I can hear the next problem that has to be knocked over, the "oversharpness" of the treble, as some may call it. Which is why a lot of people pull back from this sort of replay - it's not a problem with using horns per se but the fact that the easy dynamics exposes more vividly the underlying system distortions ...
Absolutly agree. I had suppressed any tweeter on my 2 way system, and worked a lot to remove all the harshness and nasal effects of the horn. I use wooden spherical horns, it goes up to 16Kz very flat and in a very credible (natural) way.
You can notice, in the pioneer video, that, moving the mike's camera, there is a moment where the female voice is absolutely natural.
That what i'm now looking for, instead of impressive high trebles or deep basses. Easy listening, separation between instrument, high instant dynamic (ease) and less room's effects as possible. Nothing can beat good (rare) horns in that quest when you have suppressed the 'duck' effects.

I was very interested by those bad recordings, as they reveal instant all the huge problems of each systems: peaks in high and trebles, induced room resonances etc. without to be impressed and biased by the high volumes or beauty of some details...
Will use this kind of test intensively for my future mods.
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