Re: What band instrument is the loudest out of the jazz band instruments?

Hi, Jordan.

Honestly, this is an impossible question to answer with anything nearing 
100% accuracy, but I can at least give you the conventional wisdom in the 
matter.

Of the instruments you mentioned, the electric guitar and the drum kit 
will sound the loudest to a human listener.  The drum set sounds loud 
partially because of the natural amplification the bodies of the drums 
create, but also because the human ear is very sensitive to the high-
pitched sounds the cymbals and snare drum make.  The electric guitar will 
sound loud because, well, you plug it into an amplifier.  Generally, 
though, the director makes the guitarist tone things down because the 
guitar is rarely a featured instrument in a jazz band.

Aside from that, the bass guitar would be right up there, but since we 
aren't as sensitive to the low pitches, it won't sound as loud to us.

After that, trumpet and trombone are next in that order.  Within the sax 
section, the bigger, the louder.  The piano falls somewhere within the 
saxes as far as loudness.  Personally, I've always felt the piano is 
louder than an alto or tenor sax, but a bari player with enough air to 
fill the instrument can overblow a piano with little difficulty.

Being a big fan of jazz myself, I should mention that there have been a 
great many other instruments used in big bands over the years, including 
even things like violin and bassoon!  But there is one instrument that has 
been used in some jazz bands that throws the balance off from what I've 
listed above.
 http://www.angelfire.com/oh/EbAltoTenorFhorn/images/Melllophonium.jpg

The mellophonium, used most notably by the Stan Kenton band (in fact, he 
had a part in inventing the instrument, and you may have seen it in 
marching band), in the hands of a capable player, can be louder than a 
trumpet.  In fact, Kenton eventually dropped his four-man mellophonium 
section after complaints from the rest of the band than they were drowning 
everyone out.  Keep in mind that at this time, the Kenton brass section 
was 5 trumpets and 5 trombones instead of the typical 4 each!  So four 
mellophonium players could completely obliterate the sound of 10 (very 
loud) brass players.

But like I said at the start of this answer, nothing is ever that simple.  
Everything depends on the ability of the player and the quality of the 
instrument, too.  So what I've said is just a rough guide.