Bronze

[Bent]

This thread is inspired by my remarks to Dave W in the Steel project#4 thread.

I need some serious opinions on using bronze in every main part of the sound chain on the pedal steel.
What I mean by that is : Changer fingers, axle, pillow blocks, string rollers, roller nut.
I visualize church bells on a Sunday morning or a ship's bell as it is leaving the dock. Beautiful, clear, lots of sustain and clean.

Bronze would have to be cast and machined. It is heavy as hell. ( you should feel my brass changer)
When a piece of brass or bronze is struck, it sounds deader than a door nail.

In comparison, aluminum sounds clean and bright when struck. I had a piece of 3/4 X5" that was shaped to a rough U shape from experimenting with plunge cutting on the mill. When I struck the "forks" it rang on forever and produced an almost perfect Bb.

So should I forget it and just stick to aluminum??

[Pat Comeau]

Bent,
i know one thing...aluminum is alot cheaper than bronze or brass

[Georg]

Bent, have you looked into how a bell is shaped to produce various harmonics? How bells of the same size can be made/tuned to sound bright or dark?

I don't think it will be easy to intentionally tune bronze parts for their tone-characteristics in a traditionally built PSG - too many mechanical issues/shapes that must come first, so you may have to rely quite a bit on luck to get the tone you are after if you try to add more brass or bronze parts than what you already have in #4.

I can see an advantage in replacing aluminum/steel parts that are in direct contact with the strings with more "inherently dead sounding" materials like brass or bronze, as I think the strings will sound clearer and sustain better when tensioned over metal parts that don't introduce too much of their own sonic waves. I will experiment with various metals and shapes for the bridge on my construction, but no matter what results I get I am not sure it they will translate well into your constructions since there will be no "changer in the bridge" to complicate "tone-tuning" on mine.

[Bent]

Pat, You are right there
Georg, food for thought. Thanks for your insights. You are likely correct on the tuning/shaping of the bell, and the impossibility of doing same with ps parts
To turn it around then, since aluminum is that much more suited sonically> why haven't someone made a church bell out of aluminum?

[Georg]

Bent, you read me wrong there. Turned into a bell aluminum will not "ring" (sustain) for long - won't charge and hold the same energy as equally sized/shaped brass and bronze bells, and aluminum will initially sound much louder and brighter.
It will be much like comparing a GFI to a Dekley for initial tone and sustain ... the GFI doesn't stand a chance on inherent "sustain" but it sure has an initial "bite".

I can see an advantage in replacing aluminum/steel parts that are in direct contact with the strings with more "inherently dead sounding" materials like brass or bronze, as I think the strings will sound clearer and sustain better when tensioned over metal parts that don't introduce too much of their own sonic waves

The "inherently dead sounding" brass, and bronze, actually take up and release lots of energy when excited, but the strongest natural harmonic frequencies are much lower (deeper) in brass and bronze than that of aluminum parts the same shape and size. So while aluminum vibrates and "sounds lively" in much the same frequency range as the strings, brass and bronze vibrates at much lower frequencies.

In my mind I want anything but having the PSG parts vibrate, and sound, in the same frequency range as the strings, as that means they steal energy directly from the strings and shortens "sustain". So I really can see an advantage in having heavy brass/bronze parts near the strings, but can't see how you can continue with brass/bronze down through the changer-fingers and the mechanics without building a heavy monster with lots of incalculable sonic couplings.

[richard37066]

To one and all -

I've made the assumption that many would not have the same textbook references so I sought out a reference that is easily accessible to all: -

http://www.ndt-ed.org/GeneralResources/ ... metals.htm

In perusing the charts, one finds that the velocity of propagation of either longitudinal (compression) or shear waves in the metals of interest (aluminum and steels while excepting bronze) are generally and essentially the same. The density of those same metals (excepting aluminum) are roughly in the same ballpark as is the acoustic impedance.

Of particular interest is the bronze category in which the velocity of propagation is significantly lower than the others. This may account for Georg's reference to lower and natural resonant frequencies in the material.

How does this equate to its' use in a changer? I don't have the foggiest notion. However, since all of its' properties differ greatly from the others, I would give it a try and see what happens. One should keep in mind that there are a ton of other undefined variables at work in the instrument. At first glance, I'm not seeing much of an advantage if, for example, the changer axle, pillow blocks, scissors, etc, are made out of aluminum and stainless. Remember, I am one who advocates the use of stainless as opposed to aluminum for finger material. The percent change in mass - if only the fingers are made of bronze - is minimal. I mention the word "mass" since I view the changer assembly as only a high mass but relatively lossless transmission medium between the vibrating string and the quite lossy wooden top. Given that to be somewhat true, it would appear that, in an attempt to effect a significant change in acoustic impedance - transmission characteristics - the entire changer would need be constructed of a bronze material. Yup - the weight of the changer will increase but not, in my view, prohibitively.

Our resident milling machine guru - Bent - is usually up to his butt in alligators but, perhaps, he can find the time to screw something together and file a report.

Richard