John Curl's Blowtorch preamplifier part II - Page 2838 - diyAudio
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Old 23rd October 2012, 11:20 AM   #28371
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An other tip is to flatten the loudspeakers impedance.

If good monitors manufacturers think to compensate the inductance impedance of the coils, very few of them care to correct the motional impedance at the resonance. Is it easy to do, with an inductance, a cap and a resistance. Do-it with your loudspeaker at free air. (according to its Thiele & Small parameters).
You will object that it will give strange results, when a bass reflex changes the impedance curve near the resonance, as well as the resonance frequency ?
Just try-it, and you will be surprised to see the flatten remains correct. Jut you can adjust the value of the resistance, if your impedance curve goes too low where the events are tuned to resonate.

The benefit ?
They are two.
First, with a flat impedance of your enclosure, your amp will have to deal less with voltage/current incoherences.
Second, it will dump your speaker in an unbelievable way: hit the membrane of your bass speaker in your enclosure. You can here the characteristic heavy "BOUM BOUM" of the resonance. With the motional impedance compensation, it wil turn in a light "kock kock" damped sound, very "fast", where resonance is at very low level and you can hear the material of the membrane.
Enjoy the difference, with a much better separation between basses and kick drums, better transients, and a feeling of increased speed and dynamic with less weight. You will feel that your enclosure has wined 1/2 octave down in the low frequencies.
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Last edited by Esperado; 23rd October 2012 at 11:23 AM.
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Old 23rd October 2012, 01:04 PM   #28372
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Originally Posted by john curl View Post
WATT
I had a chance to listen to Sophia, Watt/Puppy and Maxx, longtime. Frankly, I was not amazed by Watt/Puppy. They have very strong "character" and they are far from neutrality. I liked smaller Sophia better, for more compact sound. If I wanted a big sound, I preferred Maxx, the sound is bigger and more neutral than that of Watt/Puppy.
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Old 23rd October 2012, 01:29 PM   #28373
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Originally Posted by Esperado View Post
An other tip is to flatten the loudspeakers impedance.

Just try-it, and you will be surprised to see the flatten remains correct. Jut you can adjust the value of the resistance, if your impedance curve goes too low where the events are tuned to resonate.
Enjoy the difference, with a much better separation between basses and kick drums, better transients, and a feeling of increased speed and dynamic with less weight. You will feel that your enclosure has wined 1/2 octave down in the low frequencies.
Nice description -- havent heard the benefits described that way and now i am curious to try it on my commercial systems. Thx - RNM
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Old 23rd October 2012, 02:59 PM   #28374
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I have an early WATT speaker system that I purchased to replace the original WATT-PUPPY that Dave Wilson gave me in 1987 or so. Unfortunately, it was destroyed in a firestorm 21 years ago, almost to the day, and I went without a decent speaker for a year or two. I wanted my WATT's back, so I bought a pair, used, and I have never regretted it. I don't necessarily like the more recent WATT's for some reason. Probably the tweeter. I am still friends with Dave Wilson, but we have been out of touch for years. I too am ASTOUNDED that his best speakers now cost $200,000, and I was not that impressed with them at a listening session a few weeks ago.
I know that he 'throws money' at his speakers, spares them no cost, but I want to be AMAZED when I hear them, not just satisfied.
About 30 years ago, Dave Wilson brought his WAMM speaker system to a CES. I heard that demo and I was AMAZED. And I told him so, at the time. I know a little bit more about the design of his speakers, but I am not privileged to share that info. There is high technology in them.
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Old 23rd October 2012, 03:52 PM   #28375
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Originally Posted by RNMarsh View Post
i am curious to try it
Please keep-me informed of your subjective conclusions.
This same helps a lot to calculate and tune filters with middle and trebles, of course, and can remove some tonal characters.
It is the first thing i do before to mount any new speaker.
It has an other benefit: If your enclosure has a flat impedance, it is less sensible to any serial resistance or damping factor of the amp, regarding response's curve modification.
So , you can avoid exotic cables, use those that conduct electricity and, with the saved money, have a nice dinner with those nice virgins previously employed to cryogenic them in liquid helium.
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Old 23rd October 2012, 04:20 PM   #28376
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Originally Posted by john curl View Post
his best speakers now cost $200,000....
I know that he 'throws money' at his speakers, spares them no cost
Did-he use a brand new compressed Ferrari for each chassis, plain diamond machined cones, and gold ribbons for the moving coil's ?
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Last edited by Esperado; 23rd October 2012 at 04:25 PM.
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Old 23rd October 2012, 04:55 PM   #28377
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Originally Posted by Esperado View Post
... Do-it with your loudspeaker at free air. (according to its Thiele & Small parameters).
You will object that it will give strange results, when a bass reflex changes the impedance curve near the resonance, as well as the resonance frequency ?
...
I dont doubt that you get results with this if you say so, but nevertheless it sounds
rather counter intuitive.
One might argue that where has been an impedance peak in free air (which you now
lower or flatten), might be an impedance minimum once the speaker is mounted
in a ported box.
What is the theory behind that ? How does this work (in contrary to the more
common method of flattening the mounted speaker and frequency network) ?
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Old 23rd October 2012, 05:09 PM   #28378
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Did-he use a brand new compressed Ferrari for each chassis, plain diamond machined cones, and gold ribbons for the moving coil's ?
No Mr. Wilson probably drives a Ferrari or similar expensive car.
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Old 23rd October 2012, 05:44 PM   #28379
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Originally Posted by QSerraTico_Tico View Post
No Mr. Wilson probably drives a Ferrari or similar expensive car.
Or maybe a Bentley. Your avatar, I'm honored!
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Old 23rd October 2012, 06:05 PM   #28380
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Forgive my ignorance, but what's his avatar?
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