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Adding Analog Harmonic Content Sound Enhancers & Exciters (HW)
Old 15th August 2008
  #31
kjg
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Dear mister Deupree,

I'll have a shot at answering your question.

Quote:
Originally Posted by t_d View Post
here's a question that's always been on my mind..
can you add harmonic distortion to a sine wave?
Yes, you can, both trough analog and digital means. The answer lies in the term itself if you just take it very literally:
If the waveform that produces a pure tone (meaning no harmonics - mathematically described by the sine/cosine function, therefore a "sine wave") is distorted in any way, this will result in harmonics. Because, at that point it is not a true sine wave anymore (which would result in a pure tone) - but a distorted sine wave (which results in a fundamental with a certain spectrum of overtones. The actual spectrum depends on how the waveform is distorted).

So, the term we use to refer to describe the sounding result is what is actually happening to the waveform. The waveform is distorted, and as a result we hear extra harmonics.

Two crude examples:

Say you generate a full scale sine wave, peaking to 0 dBfs. The sounding result will be a pure tone. Amplify that waveform by some dB. The waveform was already fullscale. So, when it is further amplified, the top and bottom of the waveform will be squared off (since sample values greater than 1 and smaller than -1 cannot be represented). The waveform is now distorted and therefore it will generate harmonics on playback.

In the analog world: Connect a sine tone signal to a preamp. The sounding result will be a pure tone. Now increase the input gain until the preamp runs out of headroom. Again, the top and bottom of the waveform will be distorted, and harmonics are the result. (this is pretty much how guitar amplifier and distortion pedals generate distortion - crank it up till you overdrive a component (tube/transistor) then scale back, maybe filter a bit, and there you go, rock and roll!)

Actually, it is impossible to not distort a sine wave. Any analog device/component will distort incoming waveforms a tiny bit, resulting in harmonics. The same thing goes for speakers. No speaker can reproduce a truly pure tone, it will always distort it slightly.
And in the digital world there are always rounding errors (the nature of the beast - not all numbers can be represented in binary, you can only get very, very close, providing enough bits are used), resulting again in harmonics.
With good equipment this distortions of the waveform are either so minute that you will not notice them (clear, transparent, analytical gear), or will be somehow nice and even "musical" (warm, gritty, characterful gear).

Devices that actually add distortion (as opposed to distorting the signal itself) will most probably take a split of the signal, then overdrive it, then scale it back, and then add the original waveform in opposite polarity so it cancels out and only the harmonics remain, which can then be auditioned and blended in at will.

I'm guessing the HEDD does something similar. Maybe it is even using FFT to generate the harmonics, but I'm just guessing here. What the tape dial does I wouldn't dare to guess at all, since tape saturation is a pretty complex non-linear process.

Additive synthesis goes exactly the other way around. Summing sine tones of different frequencies to create complex waveforms. Here's a nice animation of a how (an approximation of a) square wave can be generated from sine waves: Image:Synthesis square.gif - Wikipedia, the free encyclopedia

Well, that turned out to be quite a long reply to such a simple question! I hope it sheds some light on the topic...

To conclude I'd like to say that I am an admirer of your work. I especially appreciate your personal musical output, but I generally enjoy most of what is released on 12k. These days I am enjoying your release "The Sleeping Morning", and "Hum" by Sawako very much. Thank you!

With kind regards,
Klaas-Jan Govaart
Old 15th August 2008
  #32
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Adam Dempsey's Avatar
 

Verified Member
Quote:
Originally Posted by masteringhouse View Post
I would say that the STC-8 is going to give you the least with regard to color factor.
Ditto. Love it, for that reason.
Old 15th August 2008
  #33
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masteringhouse's Avatar
 

Verified Member
Quote:
Originally Posted by jordanstoner View Post
Do any of the aforementioned units allow you to bypass the unaffected signal and listen to only the added harmonic distortion? I think the Aphex Aural Exciter did this...
Not the ones that I had mentioned, but as you prorbably know you can always do this by summing a polarity reversed version of the source (latency compensated) for this.
Old 17th August 2008
  #34
Gear Addict
 
E-Irizarry's Avatar
Crysonic newB is the best kick drum-bass line calibrator plugin I have ever worked with. Give that a whirl.
Old 17th August 2008
  #35
Gear Nut
 

I have the Aphex Model 250 (Type III) and it allows setting the harmonic starting point (like 3Khz), the amount of harmonic distortion, odd/even harmonic ratio, set the mix ratio of clean/harmonicedized, has a noise gate to provent adding harmonics to noise, and lets you solo the distortion. It is analog in the sense that the I/O is analog; internally it is digital processing.
Old 18th August 2008
  #36
Quote:
Originally Posted by kenjkelly View Post
I have the Aphex Model 250 (Type III) and it allows setting the harmonic starting point (like 3Khz), the amount of harmonic distortion, odd/even harmonic ratio, set the mix ratio of clean/harmonicedized, has a noise gate to provent adding harmonics to noise, and lets you solo the distortion. It is analog in the sense that the I/O is analog; internally it is digital processing.
The "Aural Exciter" (sounds like a sex toy) looks like it would be perfect for material between 700Hz and 7K. How well does the Noise Reduction function work?
Now that you've got me all excited, do people ever get rid of theirs? I saw they no longer make them. (Que trumpets) "Let the wild goose chase begin."
Old 18th August 2008
  #37
Gear Guru
 
UnderTow's Avatar
 

Verified Member
APHEX Systems 204 Aural Exciter® - Optical Big Bottom® *snigger*

Alistair
Old 20th August 2008
  #38
Old 20th August 2008
  #39
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mastertone's Avatar
 

Verified Member
Quote:
Originally Posted by kenjkelly View Post
I have the Aphex Model 250 (Type III) and it allows setting the harmonic starting point (like 3Khz), the amount of harmonic distortion, odd/even harmonic ratio, set the mix ratio of clean/harmonicedized, has a noise gate to provent adding harmonics to noise, and lets you solo the distortion. It is analog in the sense that the I/O is analog; internally it is digital processing.
Sorry maestro, its all analog inside. Opamps galore!
And it does come in handy from time to time, the only plugin that comes close to this unit is Steinbergs Spectralizer.

/ Jonas
Old 20th August 2008
  #40
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Bob Yordan's Avatar
Quote:
Originally Posted by UnderTow View Post
I have one of those. Bought it for $150.

Old 20th August 2008
  #41
Gear Maniac
 
OberHeim-Kenobi's Avatar
 

Quote:
Originally Posted by mastertone View Post
Sorry maestro, its all analog inside. Opamps galore!
And it does come in handy from time to time, the only plugin that comes close to this unit is Steinbergs Spectralizer.

/ Jonas

SPECTRALIZER Yeah it reminds me the past. I liked a lot Spectralizer . It sounded like 2nd, 3rd harmonics on Fatso. In the 16 bits DAW years it was fresh air.
Old 27th August 2008
  #42
Gear Maniac
 
majoraxis's Avatar
 

Fielding DSP Reviver - worth a listen

Hi,

Reviver is worth a listen. It is currently only AU, but most likely other platforms in the future.

Adding only third order harmonics at about 10-15% is a good place to start. Second order harmonics are also available.

There are a few treads in the new product alert section about Reviver.

Thanks, Mark
Old 27th August 2008
  #43
Quote:
Originally Posted by majoraxis View Post
Hi,

Reviver is worth a listen. It is currently only AU, but most likely other platforms in the future.
I ass-u-me that they're going to release it as HD only for ptools - like all other good plugs, (ex: Phoenix)
. . . and I'm back to square one.

I'll keep this one on the watch list though. Thanks.
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