Relative Loudness of Theatre Organ Voices

[Eric Mack]

While reading this thread on organ voicing and the relative loudness of ranks on a classical organ, I remembered seeing a section on voicing in the factory manual for my Rodgers 340. Specifically, I remembered a bar chart inside showing the recommended relative volume levels of each rank.


I understand that chart only represents a starting point for that model instrument and it will have to be adjusted from there according to the capabilities of the instrument, the room and probably a host of other things I do not yet understand.

Anyway, I like the representation and wonder what others think of this bar chart. Does this bar graph have as its origin a more formal chart, perhaps something from Wurlitzer, or a noted organ designer? Are there better published guidelines somewhere?

For the Theatre Organists out there, what would you change?

Eric

Update: I added this question to the Theatre Organ Group on Facebook as it might attract additional insights from a different group

[toodles]

In theatre organs as well as classical organs, the "norm" has always been to place stop controls in order of loudest to softest, and by ascending pitch register. The difference between classical and theatre organs, though, is that classical organs place reed stops after flues (diapasons, flutes, and strings). So by reading a sequence of stops you should be able to understand by position if a stop is supposed to be louder or softer than other stops in the same pitch register.

I guess the person who made that chart had an amplifier that went to 11, since it uses a scale of 0 to 110 :devil:. Anyhow, of those voices the loudness to softest should be post horn, trumpet, diapason, tibia, kinura, clarinet (which might be reversed, depending upon voicing of the kinura--some are delicate, some are pushy), string, flute, then vox humana. The vox is typically described as the softest voice of the theatre organ. The diapason and tibia should be of almost equal volume, and the flute should be just a little softer than the string and louder than the vox.

So I have some disagreements with that chart.

By the choice of the stops that Rodgers used, I have a suspicion that their designer either liked Barton and/or Morton theatre pipe organs rather than Wurlitzer or was more familiar with those makers.

Note that theatre pipe organ builders, at least Wurlitzer, changed their voicing somewhat from the early silent film era (where the voicing was more lyrical/suitable for silent film accompaniment) to a bolder voicing for solo work. Modern theatre organ rebuilds seem to use voicing and stop selection quite different from the silent film era for a "concert" and experience. Somewhat akin to the British "Blackpool" Cinema organ build, though in that case it was for dance hall work.

[Ben Madison]

Please continue your thoughts on the Kinura. I want to understand why the Vox not being on par with the Tibia in regards to loudness even though both ranks are the most of importance.

[samibe]

Important does not necessarily mean loud.

[Eric Mack]

Thanks for the explanation, Toodles.
I created a new chart based on your feedback and comments.


Does this accurately reflect what you had in mind? (Note: Excel decided my amplifier can go to 120%, but I promise not to drive it past 100. :-B)

Using the Rodgers table levels as a starting point, I approximated the numbers based on your positioning. How does this look?

[Eric Mack]

When voicing an analog instrument to a chart like this, how do they do it? Do they measure relative loudness by ear, with an SPL meter, or by some other means? (I realize in my living room it may not matter, but I am curious to learn from you.)

[myorgan]

I would think using a docemeter with peak hold would be the preferred method of ascertaining volume utilizing dB SPL on an A-weighted scale.

Michael

[m&m's]

I note that you included a Trumpet instead of Tuba Horn, which was more usually for theatre organs of this size (I realize that you were using your Rodgers organ as a basis for this chart.).

Any organ that has adjustable voicing can be adjusted within its limits to the taste of the owner, but the designer would have adjusted the initial setting to his idea of what a proper theatre organ should sound like. Bear in mind that, in a lot of organ installations, the Post Horn may be louder than the rest of the stops put together, sometimes being referred to as the "fire" of the organ. The Kinura is basically a soft stop, but its brightness allows it to be heard over the Tibia, which has almost no overtones; likewise, the Vox is normally used with the Tibia, even though it is so much less powerful, because its overtones color the sound of the combination.

[Eric Mack]

Thank you. Lots to learn here. Since I am new to most of this my format has been to follow a thread and process what I am reading and then try to synthesize/summarize what I have learned. Thanks for sharing.

[Ben Madison]

Yes, the Post Horn needs to be heard and make itself known it was originally intended to give balance with the heavy Flutes and Tibia. What is then the replacement if you take out the rank that was kind of rank that crowns the Reeds.

I would like to sit down and figure out Hope-Jones reasoning for the tonal design that he laid out.

[toodles]

In the early 1980's this was Rodgers's thoughts on volume levels for their 780 half classical, half theatre organ. Most voicing is done by ear, not using meters--at least that's my impression.

[Eric Mack]

Thank you, everyone, for your comments. I've learned some more as a result of this forum, and I hope others have, too. I thought I would share this funny post from a parallel discussion on the Theater Organ Group on Facebook. It's a modified diagram from John Lauter showing relative loudness of 1970's Pizza Organs.

[Ben Madison]

Thats how it aught to be