Harmonic Converger -- Warm up Amp Modelers and Kill Fizz

Started by jackstrat, October 21, 2005, 01:21:21 AM

Previous topic - Next topic

jackstrat


One of Neil Diamond's guitarists Hadley (aka Radley) has come up with a PASSIVE device he calls the Harmonic Converger.  Among other things the device tames the digital fizz associated with digital amp modelers. He describes the device as follows:

The Harmonic Converger is a 2-channel passive signal processor which changes the timbre (sonic fingerprint) of a typical modeler’s output to match that of a well miked guitar amp. Timbre is much different than frequency response, and IMHO it’s the missing ingredient in all modeling systems. In the process, the HC removes the telltale “fizziness” that gives even the best modelers away. The process employed is unique - I have never seen a circuit that modifies tone in the same fashion. The end result is a more realistic tone with more clarity and definition, especially in the critical mid-to-high frequency range. The sound appears thicker in a typical mix, and high notes do not lose their body or attack (a very common problem). There is an added “tightness” and cohesiveness to the processed sound that is hard to achieve naturally, even from a real tube amp. The HC is not a totally neutral-sounding device, nor is it intended to be - it adds it’s own special timbre (which is amazingly close to a real amp) to the mix.

Any ideas how to build such a thing?

Thanks,
Jack Loganbill



vortex

I'll bite... :P

A couple of caps and resistors with stereo in's and outs, fairy dust. :icon_biggrin:

Nasse

When you type "mojo analoguer filter" to the search funtion section you see this was shortly mentioned in the mojo thread.
  • SUPPORTER

A.S.P.

information lost...
Analogue Signal Processing

Paul Perry (Frostwave)

Before dismissing it out of hand, there COULD be diodes in it as well. A mix of low pass filtering (to reduce some of the high end artifacts) and some passive compression (maybe asymmetrical) via the diodes could change the 'timbre' for the best, in the opinion of some.

Andi

Quote from: jackstrat on October 21, 2005, 01:21:21 AM
Timbre is much different than frequency response

I'm always wary of semantic arguments in what initially look like technical posts... ;)

David

Quote from: Andi on October 21, 2005, 10:45:14 AM
Quote from: jackstrat on October 21, 2005, 01:21:21 AM
Timbre is much different than frequency response

I'm always wary of semantic arguments in what initially look like technical posts... ;)

Ummm...  hold up a second there.  This one's not necessarily snake oil, boys.  The unit is winning high praise on the Boss GT forum.  I am using a GT-3 and I have noticed...  something... in some of the distortion models that you could call "fizz".  I'm not wild about the distortion this unit generates.  However, I've pretty much settled on two of the available types and I'll just kick them in as necessary.  Since I'm now going direct into the church PA, I can't hear the finer characteristics of the effects models.  I don't hear "fizz" in what I use.  I'm also not playing at incredible high volume, either, which might have something to do with it.

Gladmarr

This sounds strangely like a gadget which I saw for "audiophiles" (aka techno-suckers) which was meant to take the "edginess" out of the analog output of CD players.  It was basically a pair of 1:1 isolation transformers.  They were supposed to "smooth" out the stairstep output of the the digital-to-analog converter.  The thing wasn't necessarily a fraud (although I couldn't hear it doing anything), but the price was a lot higher than it needed to be for a pair of little cheapie trannies.  This "passive device" may be something this simple.  Since there are inherent limitations to the frequency range of transformers, that could actually be used to "warm up" the output of these modelers.  In that case, it seems the cheaper the better for the transformers, as cheap trannies would have really limited bandwidth. 

toneman

"sounds"  like a HPF, that's HiPassFilter, of one sort or another.

Done "passively" ....

stayactive
tone
  • SUPPORTER
TONE to the BONE says:  If youTHINK you got a GOOD deal:  you DID!

Connoisseur of Distortion

you mean lowpass, i think... explain if i totally missed it.  ;)

i was thinking it might just be a lowpass filter or two. one to cut off everything fizzy, and another to "warm" the tone by taking off some distinguishable treble. the diode idea, though... not a bad idea at all! wouldn't it be active, though?

RDV

But let's not forget boys, it's tough getting that patented "Neil Diamond Tone" night after night after night after night. 

:-\ :o :-* :-\ :o :-* :-\ :P :-*
RDiamondVance


Steve Newton

Steve.
Not my circus, not my monkey.

toneman

Connoisseur,
  er...., yep that's what I meant....rolls off the highs....
my left brain wuz thinkin, but my right brain was typing.
:P
Indeed, I meant a (passive)LPF.

Using a diode would still be "passive".
ALA there's no pwr supply, it's passive.
*How* to use a diode in a passive LPF, I haven't a clue.
Show me the money, er....schemo...
:icon_biggrin:
staycorrected
tone
  • SUPPORTER
TONE to the BONE says:  If youTHINK you got a GOOD deal:  you DID!

puretube

2 antiparallell series-Schottky`s, and a cap to ground...

toneman

Wouldn't that be called more a "limiter" than a LPF??

like this--

http://www.headwize.com/projects/limiter_prj.htm


or here, down the page a bit where it says limiters--

http://people.deas.harvard.edu/~jones/es154/lectures/lecture_2/diode_circuits/diode_appl.html

sure, it's "passive".
but, would your parents approve??

stayNONpassive
tone
  • SUPPORTER
TONE to the BONE says:  If youTHINK you got a GOOD deal:  you DID!

Paul Perry (Frostwave)

Quote from: toneman on October 23, 2005, 07:06:39 PM
Wouldn't that be called more a "limiter" than a LPF??

maybe the harmonics (and everything else) are 'converging' to zero?

puretube


jackstrat

#18
Wow,
I really appreciate the input and time you've spent thinking this out. It would seem the circuit is pretty simple. The inventor epoxies the circuit once assembled to prevent anyone from taking a peek.

And as far as the fizz part, we know that the digital fizz is registering at around 5K to 5.3K. You can actually EQ it out. However, owners of the HC device say fizz removal is just one part of the device, they say the device significantly warms up the tones to make the digitial device truly sound like a warm tube amp.

Snake oil? Perhaps. But if so, there are a lot of pretty tone-savvy top-notch guitar players that swear by the device. I would buy it a New York minute if it were $100, but at $250 I just can't justify it, but would love to breadboard something together.

I believe he has incorporated some kind of tone stack with a presence boost. Perhaps diodes or something to smooth out the dynamics. Digitial produces a stairstepped output--if some how you could round off the edges of the steps perhaps it would sound smoother, more like a real tube amp.

As far as the Neil Diamond tone, not sure the inventor uses the HC live. Oh, by the way, he is an accomplished session player so evidently he is no slouch guitar player. And evidently has been modding amps and effects for many years. Detractors wish he would come up with a web site with clear sound clips that show the device's performance. Chances are Behringer will copy it and sell it for $19.95.

Jack Loganbill

Steve Newton

Quote from: jackstrat on October 24, 2005, 12:05:35 PMChances are Behringer will copy it and sell it for $19.95.

Many a true word said in jest!
Steve.
Not my circus, not my monkey.