I can tell you that the Grover sound more like a 18 Wheeler but seem to have a some quality problems. I have the Hadley Bullys which are louder and more shrill than the Grovers. The Bullys sound more like a train horn, in my opinion. The Bullys are 133 DB and good quality, and have more features (auxillary air to fill mattresses, inner-tubes, tires, etc. , an air hose, switch to turn off, a pressure gauge) than the Grovers.
I would suggest you do a search on "Air Horns", "Grover Air Horns", and "Hadley Air Horns", you will find alot of information about air horns from prior posts.
Just my $. 02!
------------------
<font color=blue>"WHITE OBSESSION" 99 Quad Cab, White, SLT, 4x4, 5-sp, 3:54's, Raven cap (cab high), Rhino liner, Stainless Nerf Bars, Stainless Rocker Panels, Tow package, Pro-flap mud flaps with Stainless Cummins "C" add to rear flaps, Valentine One, Uniden PC78LTW CB, Hadley Bully Air Horns, HOT Power Edge, Psychotty Air Induction, Braided SS Fuel Lines, 4" Jardine Exhaust (Love the deep throaty sound), 285/75R16 Cooper A/T's, Navigator 55w backup lights. </font>
<A HREF="http://albums.photopoint.com/j/AlbumIndex?u=1086000&a=9265455" TARGET=_blank><font color=red>My 99 Dodge Cummins</A></font>
<A HREF="http://albums.photopoint.com/j/AlbumIndex?u=1086000&a=9815423" TARGET=_blank><font color=green>BD Dyno Days 10/28/00</A></font>
<font color=purple>
Things to come; The clutch has let me know it is going to need attention very soon!
Pyro, 50# Boost and Fuel Pressure gauges (have Ultra lites will install shortly), PE EZ timing module and injectors (have Bully Dog step III injectors ordered), have 2 KC Daylighters (Stainless with 385,000 candlepower each), have 2 KC Fog lamps(Stainless 100w each) and waiting for Smittybilt Stainless Outland Brush Guard to arrive, then will mount guard and lights.
NRA Life Member! (Need to protect our rights and FREEDOM!!)<font size=-2>
[This message has been edited by BIG BOB (edited 12-29-2000). ]