Ultrabass, psychoacoutstic low bass for little speakers

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Dynavector used to have a similar virtual bass system, subjectively deep (but not punchy) bass coming from minuscule speakers.

Edit: I found the article on SuperStereo from the late Dr Tominari:

http://web.onetel.com/~dynavector/hi-fidelity.htm

I was lucky enough to having spent an evening with him in 1995 in Tokyo. He demonstrated me the SuperStereo system, among others. He was a very nice person, and one of the greatest inventors in audio.
 
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Go for the real thing ;)
3" paper full range with 1mm x-max has 2 options:
Ultrabass for compact enclosures (fake the low bass, avoid the x-max)
Or, Voight Half Wave enclosure (make a really big box do the bass)

And, I'm doing a little portable. It can't have a big box.
From the link in post 1 above: Like the original tube ultrabass article states "Bass without big baffles" is what I'm after, in a little portable speaker. Same as big bass without big box.

Jan Meier's op-amp graveyard looks like it could do the job with a high component count for it, but the original tube circuit demonstrates that it could possibly be done, much more simply, with about 5 fets. I'm just not quite good enough with design to convert the tube circuit to solid state.
 
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I was rather hoping for schematics; however, that article has information that could be used for programming the DSP of a radio station processor to dramatically increase broadcast range by omitting the power hogging bass fundamental. This is a bit too complex for my little portable. And the article has no schematics--the writers went big on the blather but short on the application. What could run and simultaneously apply those equations is a DSP or nanocomputer, but I'm not using one of those. It is really too bad for the radio people that the LP curves weren't used for FM radios, since bass boost in the receiver would have taken the load off the transmitter. And I've no idea how they managed to again forget the needs of the transmitter when making the transition to digital, and they did even worse. Probably there's several pagefulls of equations that explain it all to someone, and if we could read it, then it would look just like an excuse. :)

The tube circuit in post 1 shows doing Ultrabass simply with a few actives; however, I need a simple low parts count schematic suited to battery power.
 
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The tube circuit in post 1 shows doing Ultrabass simply with a few actives; however, I need a simple low parts count schematic suited to battery power.
The tube circuit can be converted to silicon using jFETs. It will not be complex or power hungry, but I am not sure the results will please you.


Anyway, I'll try to make the conversion one of these days.
 
Oh wow! Thank you!

For reference, the portable can actually reach 80hz. But it is okay if the ultrabass circuit rolls off the "real" bass at 100hz and then fakes the pitches below that. The work would fit a wider variety of projects and there'd be less x-max.

Ah, I should mention:
Average plastic mini full range = 100hz
Average paper mini full range = 150hz
Probably need a plastic/paper optional settings. :)

The actual important things for outcome are to reduce x-max, get some anti-boomy harmonic freshness on the bass and not really modify the treble. In exchanging one noise for another, the ultrabass is a prettier noise than a boomy little speaker. The fake thunder circuit has a known effect on low pitched male voice, not bad, but rather like the extra harmonics that could be done if smiling while talking. Ever want a really rockin table radio?
 
Then there's this blast from the past...
 

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Then there's this blast from the past...
And backwards. . . That's a harmonic divider to increase x-max. But, I need the opposite device to decrease x-max for 3" and 4" speakers with 1mm clearance.

The device I'm looking for is psycho-acoustic bass with the low fundamentals omitted--This has low bass sound of headphones--very pretty but no impact, and thus no x-max either.


P.S.
Ah, fond memories of the DBX and a club with a vibrating wooden floor where the drinks were cheap and all the tail was free, but then I got married and have 3" to 4" speakers that I might could use in the garage or garden. Wow, just like bait-n-switch marketing!! Anyway, need odd multiplier, not even divider.
 
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Interesting... I'd never heard about that secret weapon.

And just to clarify, the above device isn't so much a divider. It was designed to generate tones an octave lower than the actual signal (of between about 50-100Hz) and add them at the output. An idea before its time?
That is the opposite of what you're looking for, so if a similar device subtracted instead of added...
 
That's what the device I described does.

It full wave rectifies the input from the first low pass filter to produce the second harmonic plus a lot of other harmonics, then filters out the higher harmonics this produces and adds them to the original signal.
Saturating a transformer gives third harmonic only whereas this gives both second and third, the balance of which is dependent upon the roll of point of the output filter.
rcw
 
I would try a low pass filter and a full wave rectifier and mix this with the other sound via another low pass filter.
You could probably do the whole thing with a quad op amp.
rcw
304247d1349057628-ultrabass-psychoacoutstic-low-bass-little-speakers-phonybass1

This is something like the thing I would knock up...
rcw
I didn't understand this schematic because the hookup for the 2 pins of the single diode shown, is not the same as the 4 pins of a full wave rectifier.
How does that go?
 
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The one function that showed the best result according to the AES articel was some exponential with an offset. From the complexity point-of-view this shouldn't be difficult to be done in analog circuitry. The enemies (as always when doing tricks with nonlinear analog circuits) are component tolarances and thermal runaway.

I will have a look at the paper again and will show a circuit that could be used but I will not do any fine-tuning etc.

The full-wave rectifier wasn't perceived as being too good in the JAES article.

Regards

Charles
 
The diode only lets positive going signals in, when this happens there is feedback the negative going signals go via the input and feedback resistors, in this case there is no feedback until the op amp output goes positive again.

This is about the simplest precision full wave rectifier you can make.
rcw
 
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