Hello Everyone,

I recently restored my '58 444 6V Bosch horns. Wow, what a royal pain! The horn adjustment was incredibly sensitive and it took a long time to find the proper 'spot' where the horns sounded loud and crisp. Both horns have different tones from what I can tell, and from what I understand, this is normal. What I don't know though is what the frequencies are supposed to be. I know, according to the parts manual, that one horn is supposed to be HI and one LOW, but can't seem to find any reference to the frequencies or tones of the horns.

Note, my horn part numbers are Bosch HO/FDF 6(46/9) and HO/FDF 6(45/9). I have a video of the horns blowing here: https://youtu.be/9mp9qPRiVQQ.

I reached out to a good friend, Cam Price, who provided me the following information, but unfortunately no details on the frequencies:

"The horns did not sound too badly from what I could recall from my first PV544. You have the data correct and maybe my PV444 service manuals might provide more specific information?

Type
Low tone .................................... HO/FDF 6/45
High tone ................................... HO/FDF 6/46

Armature air gap:
Low tone horn ............................0.020" - 0.026"
High tone horn ...........................0.018" - 0.022"

Current consumption:
Setting value, low tone horn .......4.7 - 5.3 amps
Setting value, high tone horn ......4.2 - 4.8 amps
Limiting value, low tone horn ......3.5 - 5.6 amps
Limiting value, high tone horn .....3.3 - 5.2 amps

Voltage for armature attraction .......... 4 volts

Voltage for full tone value ................. 6 - 8 volts"

I appreciate any help you're able to offer!

Best,
--
Anthony "Tony' Scarola
1958 Volvo PV444 (aka 44408, 444L, Old Lady)
See https://sites.google.com/a/scarolas.com/www/Home/58volvopv444