Author Topic: Gulbransen Rialto III ? - The Eddie Dunstdter Studio Special  (Read 8290 times)

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Robert Sumsion

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Gulbransen Rialto III ? - The Eddie Dunstdter Studio Special
« on: September 02, 2012, 11:33:11 AM »
For many years after building my Maplin MES51-55 series organ and then-on hankering about building a Devtronix theatre organ, the time has arrived to get to business building a new combined analogue and digital studio organ.

My musical interest lies in recreating the sound of Eddie Dunstedters commercial recordings, which reflect a different taste than usual for organ musicality. Therefore this topic may not be down your street - but lets see!

Eddie used Hammond tonewheels, Gulbransen Rialtos and the Robert-Morton theatre pipe organ with Gottfried and Skinner pipework amongst the WurliTzer components for his recordings in the Loren Whitney Studio Los Angeles. Loren Whitney used the Robert-Morton in particular for recording significant numbers of church and classical organ related music LP's, Eddie was more entertainment orientated.

My new virtual organ build has WurliTzer samples from Neil Jenson, and you may ask "why imitate the imitators?" Simply that I like the sound of these old analogue instruments and would like to replicate the sounds in virtual form. With this in mind and using skills gained from recording and sampling locomotive sounds for model sound decoders over the last six years, I am applying the processes and technology to sample electronic organs.

With several Hammond and Gulbransen organs scrapped over the last two weeks alone, this has spurred me into writing this topic to gauge interest in sampling old analogue organs for posterity. It helped that in meeting David Pinnegar at the last EOCS meeting found a kindred spirit who understands the issues surrounding the preservation of organs in all forms particularly with the Percy Vickery Classical/Theatre organ made in the 1950's and whilst operational may not remain that way for ever due to its age.

I have found that in enquiring with various owners about sampling Hammond X-66's and X-77's, Gulbransen Rialto K's and Rialto II's, without exception all their instruments were unserviceable in some shape or form. In one or two cases I think they did not have the time to spare to help sample an organ and were being polite - it's a lot of work!, but in the other hand they were genuinely interested in having their organ sampled once it was working properly. The reason being that they knew from the problems they were experiencing that they were a headache to repair and get parts for whilst they did not want to loose beautifully made wooden consoles they were happy with, or the sounds from the organ. Plus once the sounds were on a Laptop they were portable unlike the originals.

Well it's at that level that I wrote to David recently and he suggested writing an opening topic - so here it is! your reading it!

With the first Gulbransen Rialto II replica voice filters being made on new PCB's I intend to sample the tones for use in Hauptwerk. The individual tones will be derived from free-phase oscillators and not locked by divider circuits. thereby allowing a greater number of pitches to be available than on the original organ, thus increasing musicality. David picked up on this and stated that "Wouldn't it be amazing to do a sampled Hammond but with a host of extra upper harmonics!" Well David picked up on what I want to achieve immediately and we now have some plans in that area.

Whilst I am building new voice filters I'd still rather sample the originals where possible. Being based in the UK, if you know of any of these organ types and owners willing to allow access for me to make samples please write to me.

- Compton Electrostatic
- Conn 642
- Gulbransen Rialto K
- Gulbransen Rialto II
- Hammond Elegante
- Hammond Tonewheel B3/C3 or similar
- Hammond X-66
- Hammond X-77
- Rodgers 340
- WurliTzer 4500

Already in hand is an extended pitch WurliTzer 625T allowing the keyboard/pedalboard range to be extended from the spinets 2x44(1x25)+13 to a 3x61+32 based console, and the opportunity to sample many ranks from a Devtronix Theatre organ.

The Hammond X series and the Gulbransen Rialto's use variations of Leslie 'Rotosonic' organ speaker cabinets, if anybody has a pair unused Leslie 102/103 Rotosonic organ speakers in the UK I'd be interested to hear from them as I am looking to acquire a pair for my project. They utilise 'space generators' to create the vibrato chorus on both the Hammond X-66/X-77 and the Gulbransen Rialto's which require Isomonic sound mixing.

I would welcome any feedback on this entire topic particularly in terms of increasing the musical capability of old analogue organs be they entertainment like mine or classically orientated.

thanks for reading.


« Last Edit: September 02, 2012, 11:40:07 AM by Robert Sumsion »
Best regards,

Robert 'Doddy' Sumsion

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Re: Gulbransen Rialto III
« Reply #1 on: September 02, 2012, 12:30:32 PM »
in case you didn't know I think  Hammond made a small number of Organs that have more harmonics that the standard X 66 and X77.
the model was the G100 and had stop tabs rather than draw bars. it wasn't a commercial success it seems.
I'm all for anyone sampling the older instruments, whether electronic or Pipe, even though I realise the amount of work involved.
I think you make good passing reference to the Leslie cabinets. These in addition with the vibrato / chorus circuitry on the organs are part of the sound of the whole Organ and aren't necessarily easy to simulate in a virtual organ.
being able to recreate the sound using recreated filters is a lot of work again, and you would have to be careful  that the tone generators you use would have to produce a waveform that was close to that produced by the original tone generators. sometimes it seems to be the small imperfections that give each instrument its own character. there is also the keying arrangement that can affect the sound as well.
But you probably know these things already !
regards  Peter B

David Pinnegar

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Re: Gulbransen Rialto III ? - The Eddie Dunstdter Studio Special
« Reply #2 on: September 02, 2012, 12:55:37 PM »

There is a problem with sampling vibrato based instruments. In your sample where do you start the vibrato? On a real instrument a note will start at any point within the vibrato variation and all notes will be affected by the same amount at the same time. If you sample a vibrato note, it will always be replayed starting at whereever the vibrato happened to start at the one original time and not randomly through the phase cycle. Similarly, with notes sampled individually, then all the vibratos of all notes played at different times will be in free phase, in contrast to the original in which all vibrato was phase locked together.

I experienced this problem when assisting a pop group in a recording session and we sampled a foot blown pipe organ. The note wobbles slightly when one adds air to the reservoir. As this happened randomly through the sampled notes, and replayed the notes all wobbled independantly, the result of the pipe organ samples was that of a warped Hammond.


By the way, I have a straight 1937 Hammond E which has the original double tonewheels to produce its chorus effect which might also be useful for sampling.

Playing straight on a Hammond is a very valid exercise for any pipe organist as it teaches one construction of sound by addition of tone.

Best wishes

David P


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Re: Gulbransen Rialto III and sampling
« Reply #3 on: September 02, 2012, 03:01:57 PM »
you wrote
"On a real instrument a note will start at any point within the vibrato variation and all notes will be affected by the same amount at the same time." 
I think it may actually be more complex than that.
"I have a straight 1937 Hammond E which has the original double tonewheels to produce its chorus effect which might also be useful for sampling."
I personally think it would be extremely useful for sampling, as there are not many Hammonds with the extra set of tone wheels, that produce tones at a higher and lower pitch to the original tone wheels, in the UK.

regards  Peter B


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