John Curl's Blowtorch preamplifier part II

[Esperado]

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.

[PMA]

Originally Posted by john curl

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.

[RNMarsh]

Originally Posted by Esperado

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

[john curl]

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.

[Esperado]

Originally Posted by RNMarsh

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.

[Esperado]

Originally Posted by john curl

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 ?

[gk7]

Originally Posted by Esperado

... 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) ?

[QSerraTico_Tico]

Originally Posted by Esperado

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.

[scott wurcer]

Originally Posted by QSerraTico_Tico

No Mr. Wilson probably drives a Ferrari or similar expensive car.

Or maybe a Bentley. Your avatar, I'm honored!

[Johnloudb]

Forgive my ignorance, but what's his avatar?