How does this Riedl bass work?

[Marko Ursin]

http://www.ebay.com/itm/Riedl-bass-e...item1e78d1a4ee

How does this bass work?
Marko

[jonson]

Like this..

[rhgwynn]

Maybe I an wrong but, aren't transducers piezoelectric??? You can get basses that have them under the bridge, embedded in the saddles, etc. I didnt take time to study the entire patent, but at first glance the ebay ad seems a bit misleading.

-Rob

[Steve Conner]

It seems to work exactly like the system that Joseph Rogowski/bbsailor has been promoting on here for years. The strings themselves are used as the transducers. I wonder if bbsailor has the prior art?

[David Schwab]

It seems to work exactly like the system that Joseph Rogowski/bbsailor has been promoting on here for years. The strings themselves are used as the transducers. I wonder if bbsailor has the prior art?

That was already patented.

http://www.pat2pdf.org/patents/pat4408513.pdf

This patent also features a magnetic pickup, but the main part is the strings vibrating over magnets. Of course the patent was in 1983, but I don't see it cited in prior art.

I'm quite sure it was done another time on at least one other instrument.

[David Schwab]

Maybe I an wrong but, aren't transducers piezoelectric??? You can get basses that have them under the bridge, embedded in the saddles, etc. I didnt take time to study the entire patent, but at first glance the ebay ad seems a bit misleading.

-Rob

Transducer: a device that converts variations in a physical quantity, such as pressure or brightness, into an electrical signal, or vice versa.


A magnetic pickup is a transducer, as is a piezo pickup.

[g1]

So this is supposed to be able to mount to any guitar without routing, with all the electronics (dsp) being in the plastic of pickguard and pot base?
"[0005] The present invention is a device that uses an integrated system of electronics and at least one bipolar magnet that is packaged on a thin and compact plastic tray that can be slipped between a guitar's strings and the body of the guitar. The device requires no holes be cut into the guitar and includes a volume control, output jack and an off-on battery switch on the tray. The device typically works with batteries that provide direct current and the entire device can be unplugged and removed if the player wants to play the guitar acoustically. The bipolar magnets may be placed anywhere on the tray as long as they are located near, or preferably under the guitar strings. As the magnets may be moved to different locations near the strings, the change in location of the magnets causes the various tones to be available to the player. If the magnets are moved rapidly, tremolo effects can be heard. The magnets may be of virtually any shape, although it is preferred that the magnets remain small and compact in size"
Not sure how you would move those magnets rapidly, or couple the electronics to the strings of "any" guitar, apparently they run a cable down the trussrod from the tuners.
Much of the emphasis on what separates it from prior art seems to be noise reduction (via dsp).
"[0009] Transducers that are able to detect low amplitude vibrations from stringed instruments are well known in the prior art. The primary limitation of many transducers that utilize electromagnets is that most amplifiers must overcome the elimination of noise from the signal.
[0010] Other inventions in the prior art have attempted to overcome this problem. For instance, in U.S. Pat. No. 5,723,805 for Lacombe, the patent discloses a transducer for sensing low amplitude vibrations of stringed instruments. However, Lacombe's invention makes no mention of filtering noise. Additionally, the disclosed invention requires among other things an extensive modification to the guitar including the creation of new holes, and the potential need to reset the neck and utilize an expensive brass nut. Lacombe also utilizes single-ended amplifiers that allow a substantial amount of noise that is highly undesirable. Furthermore, Lacombe does not disclose the shielding of the circuits or cables in order to reduce noise, nor does Lacombe mention the use of ground planes near his circuits."
http://www.patentlens.net/patentlens...emming=&pid=p0
So the ebay ad mentions "virtual rhythm guitar audio", more from the dsp I guess. Now if I can just figure out why this thing really needs strings at all, seems so primitive and un-"virtual" .

[bbsailor]

It seems to work exactly like the system that Joseph Rogowski/bbsailor has been promoting on here for years. The strings themselves are used as the transducers. I wonder if bbsailor has the prior art?

Steve,

The earliest prior art is Meissner patent 1915858 June, 1933. In this patent he uses magnets to induce a voltage into vibrating piano strings.

The laws of physics cannot be patented but methods of implementing the many variations can be patented. Such variations include using DC voltage to magnetize soft metal into making magnets under strings. Using the truss rod or truss rod path as a ground return. Using a brass nut to be the common ground of the strings vice connecting wires to each machine head. Using transformers to convert the low impedance of an individual string to a more useable higher impedance and higher operating level. Alternating the phase of adjacent strings to minimize hum. In the Reidl bass, using balanced input active low noise circuits vice transformers.

The easiest thing a guitar maker or bass maker can do is to lay a ground return in the neck while it is being made for an easy optional retrofit later on. A vibrating string in a magnetic field generates between 2 and 5 mv depending on the length of the magnet field under the strings. There are many ways to create variations to capture that voltage and convert it to a higher level and more useable impedance. One of the simple ways is to use a single toroid coil with many thousand of turns on the secondary and then loop a variety of wire turns through the toroid from each string attached behind the bridge to the common ground return. By adjusting the number of turns on each string and the wire gauge, the individual string levels can be adjusted and voiced. Every variation on implementation can result in a new patent. I have seen many!

Joseph Rogowski