I dissassembled the trumpets to paint, then realized there's a note on them, and unscrewing the trumpet from the horn body affects the tuning. Can't have them out of tune Anybody get some tuning electronic gadget from eBay for $12.99 etc that will help set the pitch on a musical instrument??
If you have a medium to high-end electronic keyboard, select the trumpet voice. If it happens to have a pitch-bend roller, roll it down just slightly. That signature duo-tone, on the higher octave end is: F and B flat https://www.youtube.com/watch?v=Y4E8loO1LPk
Perhaps you can use a spectrum analyzer app on your phone if we can figure out the right frequencies.
Interesting on the iPhone apps. I have them for stringed instruments, but I don't think I have an F and B-flat. Hmmmmmmmm ?????
Cool thread and excellent timing. I just finished restoring my horns and was about to reinstall them without tuning. You want to look for a "chromatic" tuner. The app you already have will probably work -- most tuner apps default to guitar mode, but can usually be changed to chromatic mode in the settings.
It's hard to know for sure what to tune to. The 328 horns in the video above seem to be tuned to F and F#. The horns in the video below seem to be E flat and G (they are Ferrari FIAMM horns but they are for much later models): [ame=http://www.youtube.com/watch?v=50CiBmK1mfQ]Ferrari Air Horn - test blow before installing into a Hudson Pickup Truck - YouTube[/ame]
The frequency of each horn is due to the construction of the horn (length of the trumpet, etc.). The adjustment of the end of the horn trumpet where it contacts the diaphragm does not have much of an effect on the frequency. If the horn doesn't contact the diaphragm, then the air goes around it and doesn't vibrate it. If it is too tight against the diaphragm, then it won't open it. Both horns must be connected together with the "Y" junction and operated with the compressor that you are going to use in the car. Make sure that the compressor is working well, recently lubricated. Put on some hearing protection, and then just adjust each horn for the best tone by ear. If one horn is adjusted too tight then the compressor will only operate the horn that is loose/easier to open, which is why they must be adjusted together. You can feel which horn is working by putting your hand in the end of it when you blow them. You just turn them a little bit at a time until they sound good together. You will know when they are right. When they are not right, they sound awful. It takes just a little time. Be sure to do it in a place where you are not going to bother other people.
I actually did something similar to what motob mentioned. I put on hearing protection, closed all doors and windows, and did the test with a bunch of short bursts making adjustments in between. It took a bit, and I must say that I felt I got it close enough, then packed it up. But having noticed the notes stamped on the horns, I thought that would be great to aim for perfect tune with a cool iPhone app.
There seems to be a subtle variation out of the factory. This video probably captures it best, all airhorns, yet some sound different. https://www.youtube.com/watch?v=JY2TGjdN8Co
I just tuned the horns. I used Motob's approach to get the best sound quality in each horn and then used an iPhone app (named "Piano Tuner" (Free)) to fine tune them. The natural tones (getting the best sound) seem to center around E and E flat, so I tuned them exactly to E and E flat with the tuner. The more modern horns in the video RacerX_GTO posted seem to be mostly tuned to F# and G#, which is a different "chord" (a full step versus half-step on mine). I'm not sure if I have mine right because of the difference in half-step versus whole-step. I found it pretty hard to discern which setting sounds best by ear when they are blasting so loud in your ears (even with ear protection, which you MUST have to do this). I also measured the volume at 124db. Image Unavailable, Please Login
I installed the horns today. I wasn't sure I had them right when they were blasting in my ear during tuning, but they sound pretty good now that they are in the car. These were tuned to the general area where each horn sounded best and then fine tuned to E and E-flat with a tuner. The pitch went slightly flat when I locked down the nuts, but they both changed roughly the same amount to keep the same half-step interval. Ferrari 330 Fiamm horn test - July 6 2013 - YouTube
My wife is tone deaf. Challenged by subtle color variations and has no sense of smell. She is perfect in that she defers to my sense of color,tone and aroma. The perfect wife in those areas without argument. GTS Bruce
