2x12 cab wired at 4, 8 or 16 ohms...any difference tonewise?

[The Rocket]

Hello Tone-Gurus,
maybe this is a dumb question, but I was wondering if there is a difference in sound if the cab is wired at 4, 8 or 16ohms...
Is 8ohms preferable to 4ohms?
What is the best in a 2x12 cab?
Thank you very much.

[Old Tele man]

...typically, the lower-Z load will exhibit tighter bass-response while the higher-Z load will exhibit slightly more airy treble-response, but it also depends heavily upon the speakers' construction, such as cone material & shape, as well as type & size of "cap" used.

[The Rocket]

...typically, the lower-Z load will exhibit tighter bass-response while the higher-Z load will exhibit slightly more airy treble-response, but it also depends heavily upon the speakers' construction, such as cone material & shape, as well as type & size of "cap" used.

Thank you very much for taking the time to answer!
Sorry for my ignorance, but... is "lower impedence" = 16ohm
or 4ohm?

:o

[Old Tele man]

...lower-Z refers to 4-ohm and higher-Z refers to 16-ohm, sorry.

[The Rocket]

thank you very much!

[Kiwi]

Yes, it will make a surprising difference.

Examples (learning experiences along the way):

- Matchless Clubman and DC30 want to see 4 ohms for the astonishing sparkle, chime, and grunt they can project;

- Germino Club 40 (Greg's version of a mid-60s JTM50) wants to see 16 ohms;

- Vox Heritage AC-30 HH wants to see 16 ohms also;

- Fender Blackfaces want to see 4 ohms but will grudgingly accept 8 ohms.

I'm no techie. I play this stuff, that's all, and I can't explain it.

But you know it when you hear it.

+K+

[Old Tele man]

...actually there *is* an answer as to why: consider a 50W output amp and what the voltages & amperages would be across the different speaker(s) Z-loads:

2-ohms (ie: 4x10"): SQRT[ 50W/ 2-ohm ] = 5.00A & 10.0V
4-ohms (ie: 2x12"): SQRT[ 50W/ 4-ohm ] = 3.54A & 14.1V
8-ohms (ie: 1x15"): SQRT[ 50W/ 8-ohm ] = 2.50A & 20.0V
16-ohm (8+8 ser.): SQRT[ 50W/16-ohm ] = 1.77A & 28.3V

...and, since SPEAKERS (just like motors) are CURRENT devices (ie: ampere-turns), it's makes sense that the lower-Z speakers are supplied with LOTs more current -- although at an proportionately lower VOLTAGE -- when driven with 50W of power through (one assumes) a properly "tapped" output transformer.

...and, just like an electric motor, that greater CURRENT produces snappier "torque" (motor terminology) which translates sonically into tighter bass and mids...but, does not work for highes (due to counter-EMF effects).

[s2khawk]

Great thread and great responses. I'm an old pro at all this and all that's been said is dead-on so all I'll add is to watch the factory cabs ohm load for respective amps i.e.--matchless and the cabs are wired at 4ohm which isn't very 'british' but it nails the tone most people expect from a matchless. I've seen several times that if you want the true matchless tone you gotta get one of the stock cabs and this thread explains why...same goes for Vox, fender, and marshall of course.

[DGDGBD]

Thanks old tele man. Nice to have a logical scientific expanation to stuff otherwise relegated to "mojo". With regard to the related "parallel vs series" subject, I've experienced that 2 speakers in parallel also sounds a bit snappier, livelier, compared to series. Is this due to the lower Z of parallel compared to series, or is there somethign else going on? ...actually there *is* an answer as to why: consider a 50W output amp and what the voltages & amperages would be across the different speaker(s) Z-loads:

2-ohms (ie: 4x10"): SQRT[ 50W/ 2-ohm ] = 5.00A & 10.0V
4-ohms (ie: 2x12"): SQRT[ 50W/ 4-ohm ] = 3.54A & 14.1V
8-ohms (ie: 1x15"): SQRT[ 50W/ 8-ohm ] = 2.50A & 20.0V
16-ohm (8+8 ser.): SQRT[ 50W/16-ohm ] = 1.77A & 28.3V

...and, since SPEAKERS (just like motors) are CURRENT devices (ie: ampere-turns), it's makes sense that the lower-Z speakers are supplied with LOTs more current -- although at an proportionately lower VOLTAGE -- when driven with 50W of power through (one assumes) a properly "tapped" output transformer.

...and, just like an electric motor, that greater CURRENT produces snappier "torque" (motor terminology) which translates sonically into tighter bass and mids...but, does not work for highes (due to counter-EMF effects).

[Groovey Records]

:munch