1x12 vs 2x8 and Perceived volume

gball said:
It really was. I got it for portability and was using it with my little Mark 5:25 head. I didn't expect all that much from it TBH so it really surprised me how it could flap your pants. Turned up it had a ton of projection and sounded much, much larger than it was. Now I kind of wish I hadn't sold it!
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Hmmm. Oh no. More potential toys
 
Astral Traveler said:
What do you think, volume wise, 50 watts through 2x8 or 25 watts through 1x12. Which would be louder?
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First rule: doubling the number of speakers gives 3 dB more output. Doubling the power as well - the output voltage increases by just these 3 dB.

In real life, it depends on several factors, especially the efficiency of the speakers.
As a rule of thumb, a 12" speaker has 6dB larger efficiency than an 8" speaker (all of the same impedance, say 8 Ohms). So You need (as the same rule of thumb) a 4x8 cab to compete with the 1x12.

The 4x8 in this example will be 4 Ohms and require more current but less voltage than the 8 Ohms 1x12 cab which the output taps of the OT will happily deliver.

EDIT: the bandwidth of the speaker, foremost its free air low frequency resonance, also has a very noticeable impact on speaker efficiency. The smaller the bandwidth, the larger the efficiency. That's the reason why guitar woofers usually are significantly more efficient than bass woofers of the same size.
 
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bea said:
First rule: doubling the number of speakers gives 3 dB more output. Doubling the power as well - the output voltage increases by just these 3 dB.

In real life, it depends on several factors, especially the efficiency of the speakers.
As a rule of thumb, a 12" speaker has 6dB larger efficiency than an 8" speaker (all of the same impedance, say 8 Ohms). So You need (as the same rule of thumb) a 4x8 cab to compete with the 1x12.

The 4x8 in this example will be 4 Ohms and require more current but less voltage than the 8 Ohms 1x12 cab which the output taps of the OT will happily deliver.

EDIT: the bandwidth of the speaker, foremost its free air low frequency resonance, also has a very noticeable impact on speaker efficiency. The smaller the bandwidth, the larger the efficiency. That's the reason why guitar woofers usually are significantly more efficient than bass woofers of the same size.
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In this case being a SS amp, no OT however the output is doubled in terms of power at 4 ohms. I still think the 12 will win as well but a test would be interesting.
 
Mr Grumpy said:
She can notice a tiny incremental change on a volume dial from several rooms away and KNOW its twice as loud!
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Our brain is not good in "measuring" absolute loudness - that's the factor of 10 Ivan mentioned (which actually varies between 2 and 10).
On the other hand our brain is a lot more sensitive toward relative differences in loudness. Here 1 dB (10%) can make a large difference.
 
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