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nope. it's a decrease of 3.5dB, which is just enough to notice a difference. most people will tell you they've heard a difference, if they've done such a comparison.

 

many people will also tell you that their 8Ohm cabinet sounds better than an otherwise identical 4Ohm cabinet. there are many reasons for doing this, and i'm not at all averse to going into them.

 

but i'll assume you're asking about these particular power levels because you have an amp rated for them, and you're trying to select the right cabinet to complete the rig.

 

robb.

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Originally posted by MasteroftheGfithfretDstring:

but 3.5 dB is nothing in a live situation huh? It just save peoples ears? :)

it's not nothing, but it's certainly not like adding another cabinet or doubling the wattage of your amplifier. you'll notice a difference -- it will be louder -- but it's not the biggest difference you could make.

 

robb.

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Originally posted by robb.:

 

many people will also tell you that their 8Ohm cabinet sounds better than an otherwise identical 4Ohm cabinet. there are many reasons for doing this, and i'm not at all averse to going into them.

 

robb.

I've heard something like this before, though before it was relating to guitar speakers. Out of curiosity, what is the reason for this? Also, would using 4 16ohm speakers in a 4by10 wired in paralell to make a 4ohm cab sound different and/or better than using all 4ohm drivers wired in series/paralell to make the same total impedance?
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the reason is damping factor. essentially, the more load impedance you have hooked up to the output of your amplifier, the more control over that load your amplifier will have.

 

why? damping factor is more than just a vague, abstract notion. it's actually a formula -- the ratio of load impedance to output impedance.

 

damping factor = load impedance / amplifier output impedance

 

the output impedance of an amplifier is usually very low. for example, i used to own a crown K2 that had a damping factor over 3,000 from 10Hz 400Hz, which means the output impedance was under 3miliOhms for that entire range. (damping factor is calculated at 8 Ohms, since that increases its published number.)

 

as you can see, though, damping factor is a dynamic number, not a constant. among other things, connecting a lower load impedance will decrease the damping factor. this is also why you should use the fattest, shortest speaker cables you can. the lower resistance you have in your speaker cables, the lower the resistance the speaker sees.

 

the reason behind all of this is current. the more current you're asking your amplifier to source to your load, the less control the amplifier will have over its output. the lower the load impedance, the more current the amp sources, which means is has less control over its output. it's like pouring water out of a bucket instead of out of a glass. it's just a lot harder to control, even if you're more than capable of holding the bucket up and pouring water from it.

 

to bring it all back, the reason why many people prefer the sound of an 8 Ohm cabinet is because, at the source, the amplifier has more control over the signal. bass is tighter and the sound is more focused and coherent.

 

i've never experimented with the sound of parallel wiring versus series wiring. i can go either way with a gut reaction, but the fact is i just don't know definitively either way.

 

robb.

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