OT: 8ohm vs 16ohm cab

[modmod]

i supposed a 15w guitar amp will sound louder when driving a 8 ohm speaker instead of 16 ohm ? since it takes more current to drive 8 ohm than 16 ohm,other than that any side effects also ?  :?  thanks

[petemoore]

Lower ohmage speaker[s load an amp more. Less resistance means more power output....don't exceed the minimum ohmage...if it shows [back panel print] 8ohm min. don't try 6ohms speaker load.
  Yes 8ohm 'll sound louder than 16ohm load...all settings the same, however...turning the volume up on the amp also increases load...
 Tube amps may like the load, transistor amps IME sound about the same [if volume knob compensates] except DOnt' like being overloaded.
 Increasing speaker facia size [more speakers bigger cab] can [maybe] get more volume from any given amp...*Usually do, and better low bass response.
 *Usually...component specifics, actual amp used...etc. ...depends on many things...I suggest/tell you.. don't exceed the minimum [don't go lower ohmage speaker[s load] than the specs on the amp...other than that whatever sounds better when A'Bing is what I go with.
 Use the ohmmeter to test whatever replacement or original coils you are actually using...if the cone was changed, the marking on the back of the speaker indicating ohms could be Wrong.
 Getting louder And better [more bass and loss of harshness]....more speakers generally is the rule there...driving 'a' speaker harder generally changes the sound of it, they all have a 'ceiling' for good sound...
 If you'd like to read a ramble on speakers...

[vanhansen]

Not really louder, if very much at all.  Just working harder.  Most amps that small are rated at 8 ohms so working with 16 is ok.  The problems than can come in are when you run two 8 ohm speakers in parallel (4 ohms).  That can hurt the amp over time.

Do a google search for impedance matching or something in that area.

[scottosan]

i supposed a 15w guitar amp will sound louder when driving a 8 ohm speaker instead of 16 ohm ? since it takes more current to drive 8 ohm than 16 ohm,other than that any side effects also ?  :?  thanks

A lower impedance speaker will not neccessarily be louder.  Although it draws more current, it is less efficient than a higher impedance speaker.

[Aharon]

If you are talking tube amps,the output transformer does not set the impedance,impedance is a ratio set by the winding of the coils,in other words :it's reflected impedance.
If you plug an 8 ohm speaker into a 16 ohm output you will halve the reflected impedance the tubes see(in the primary coil) so for example a 5000 ohm primary will become a 2500 ohm primary.
Tube amps are tolerant of mismatches to a point.

GEO has a good article on this.
SS amps I don't know and I don't really care much except I would not mismatch them.
Aharon