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danielwritesbac 28th September 2012 01:25 AM

Ultrabass, psychoacoutstic low bass for little speakers
The Wireless World Archive, Bass without big baffles
The modern circuit (link below with op-amp graveyard) has far more parts than the first circuit (link above with just a few tubes).
HeadWize - Project: The Psychoacoustic Bass Enhancer by Jan Meier

How would I do a low parts count transistor/chip ultrabass circuit to help a 3" speaker? The tube circuit looks okay, except that I've got battery power. Help?

phase_accurate 28th September 2012 06:55 AM

If you have access to the JAES then this article might be of interest. They made an evaluation of different mathematical functions used to generate harmonics for bass augmentation using the residual effect.

AES E-Library Perceptually-Motivated Objective Grading of Nonlinear Processing in Virtual-Bass Systems

They checked for both, the enhancement of bass tones and the negative influence on signals that should not be affected by the circuit (like soprano voice for instance).



lcsaszar 28th September 2012 08:16 AM

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:

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.

danielwritesbac 28th September 2012 10:26 AM

I didn't have access to JAES. The Dynavector also didn't have a schematic.

Any cool low parts count schematics suitable for battery operation?

lcsaszar 28th September 2012 02:06 PM

Go for the real thing ;)

danielwritesbac 28th September 2012 02:31 PM


Originally Posted by oshifis (
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.

morinix 28th September 2012 03:38 PM

I have the JAES article. Too much math for me but PM me with an Email......

danielwritesbac 28th September 2012 09:32 PM

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.

Elvee 29th September 2012 10:24 AM


Originally Posted by danielwritesbac (
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.

danielwritesbac 29th September 2012 12:22 PM

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?

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