Difference between 2 8 ohm cabs and 1 4 ohm cab

yadge66 · #1 02-07-2011, 09:07 AM

I was thinking about getting an avatar b410 cab. I was originally planning on getting it in 8 ohms, so that later (soon) I could add another one to my rig for effectively 4 ohms. That's how I've been doing it with my current rig. (just been looking to upgrade the cabs)

But then I thought maybe I should just get the 4 ohm version of the cab. It would save me 500 dollars and I'd get the same wattage. But more speakers give more perceived loudness, correct?

I'm just wondering what the real difference would be between the 2 8 ohms and the 1 4 ohm. And if the 2 8 ohms really are louder, if it would be worth twice the price.

Also, 1 cab is always easier to move around than 2.

Also, a side question, does anyone have any experience with how fast avatar ships?

Jim Campbell · #2 02-07-2011, 09:14 AM

Quote:

Originally Posted by yadge66

I was thinking about getting an avatar b410 cab. I was originally planning on getting it in 8 ohms, so that later (soon) I could add another one to my rig for effectively 4 ohms. That's how I've been doing it with my current rig. (just been looking to upgrade the cabs)

But then I thought maybe I should just get the 4 ohm version of the cab. It would save me 500 dollars and I'd get the same wattage. But more speakers give more perceived loudness, correct?

I'm just wondering what the real difference would be between the 2 8 ohms and the 1 4 ohm. And if the 2 8 ohms really are louder, if it would be worth twice the price.

Also, 1 cab is always easier to move around than 2.

Also, a side question, does anyone have any experience with how fast avatar ships?

depends on whether one 4 0hm 4x10 will meet all your volume needs.....do you always have pa support.....

And I · #3 02-07-2011, 09:14 AM

it's not just perceived loudness, it's actual loudness. more speakers move more air. more wattage with the same number of speakers will get you a little more loudness, but probably not enough to notice. if you were to A/B/C the setup with the same head, A) one 8 ohm 410, B) one 4 ohm 410, and C) two 8ohm 410s, the "C" option would blow the other two out of the water. B would probably get you more headroom than A, but I'm not really sure how to measure exactly how much more volume it would get you. depends on the specifics of the cab and drivers i think.

billfitzmaurice · #4 02-07-2011, 09:14 AM

Quote:

Originally Posted by yadge66

But more speakers give more perceived loudness, correct?

Correct. Power and loudness have no direct correlation. Loudness is measured in decibels, not watts, and there's no linear relationship between the two.

playerunk · #5 02-07-2011, 09:18 AM

The difference between 1 8ohm cab and it's 4ohm counterpart is marginal. The X watts you get extra do not make a huge difference and you may not like the sound [those extra watts push the drivers even more and you could get a harsh(er) sound]. Plus for a perceived 'double loudness' you need 10x the power..so think how little those 100-150w will add.

With 2 410 you will have double the speaker area so more volume, more bottom and the speakers are safe if you crank it.

**jlepre** · #6 02-07-2011, 09:18 AM

Quote:

Originally Posted by And I

it's not just perceived loudness, it's actual loudness. more speakers move more air. more wattage with the same number of speakers will get you a little more loudness, but probably not enough to notice..

+1

yadge66 · #7 02-07-2011, 09:27 AM

Ok... so the 2 8 ohm cabs will definitely be noticeably louder?

Then there's also that I don't even know if I'd be using the full power I have available. I'm planning on going pre amp/power amp, and using a crown xti 1000 power amp. Which is 1400 watts at 4 ohms mono bridged. Currently I'm using a 500 watt gk microbass amp. And the whole reason I want to upgrade is because I blew a speaker from pushing my amp too hard even though the cabs were rated for 400 watts each.

So anyway, if I'm only going to be using like 800 watts or so (just pulling that from nowhere) I might be able to just turn up more on the 4 ohm cab to match the volume of the 2 8 ohm cabs. Say I'm using 800 watts total for the 2 cabs, I could possibly just go to around 1200 watts on the 1 4 ohm.

I definitely like the idea of a full stack, but I wouldn't mind saving 500 dollars...

Oh and I would say I don't always have pa support. But if I didn't have pa support it would be a smaller venue. But I play metalcore. With 2 guitarists and a loud drummer.

EDIT: After reading the posts that were posted while I was writing this post, it seems like even going from 800 watts across 2 cabs to 1200 across one wouldn't really cut it.

But I suppose I could just get a 4 ohm cab and have 1400 watts available and then when I get a second one switch to 4 ohm not bridged, which is 500 watts per channel.

togglehead · #8 02-07-2011, 09:55 AM

Quote:

Originally Posted by yadge66

Ok... so the 2 8 ohm cabs will definitely be noticeably louder?

Then there's also that I don't even know if I'd be using the full power I have available. I'm planning on going pre amp/power amp, and using a crown xti 1000 power amp. Which is 1400 watts at 4 ohms mono bridged. Currently I'm using a 500 watt gk microbass amp. And the whole reason I want to upgrade is because I blew a speaker from pushing my amp too hard even though the cabs were rated for 400 watts each.

So anyway, if I'm only going to be using like 800 watts or so (just pulling that from nowhere) I might be able to just turn up more on the 4 ohm cab to match the volume of the 2 8 ohm cabs. Say I'm using 800 watts total for the 2 cabs, I could possibly just go to around 1200 watts on the 1 4 ohm.

I definitely like the idea of a full stack, but I wouldn't mind saving 500 dollars...

Oh and I would say I don't always have pa support. But if I didn't have pa support it would be a smaller venue. But I play metalcore. With 2 guitarists and a loud drummer.

EDIT: After reading the posts that were posted while I was writing this post, it seems like even going from 800 watts across 2 cabs to 1200 across one wouldn't really cut it.

But I suppose I could just get a 4 ohm cab and have 1400 watts available and then when I get a second one switch to 4 ohm not bridged, which is 500 watts per channel.

This is kinda how i run my aggie DB750. I have two 4 ohm cabs...and usually only bring one...but i have two for the times i need the extra volume. Each cab runs at about 500 watts in 2ohm mode...but about 750 in 4ohm mode...theres no DOUBT the two cabs are WAY louder than the one, even if each is getting less wattage.

Does that head you have handle 2ohms?

yadge66 · #9 02-07-2011, 10:03 AM

Quote:

Originally Posted by togglehead

This is kinda how i run my aggie DB750. I have two 4 ohm cabs...and usually only bring one...but i have two for the times i need the extra volume. Each cab runs at about 500 watts in 2ohm mode...but about 750 in 4ohm mode...theres no DOUBT the two cabs are WAY louder than the one, even if each is getting less wattage.

Does that head you have handle 2ohms?

It handles 2 ohms per channel, but in bridge mono it only goes to 4.

8 ohm: 275 watts per channel
4 ohm: 500 watts per channel
2 ohm: 700 watts per channel
8 ohm bridge mono: 1000 watts per channel
4 ohm bridge mono: 1400 watts per channel

So one 4 ohm cab (in bridge mono) would have 1400 watts available to it, but 2 4 ohm cabs would have to do 500 watts each, or 1000 watts total.

Also I don't have this power amp yet, I'm just waiting to get some cash in to buy it with a bbe bmax-t pre amp. And then I'm gonna sell the cabs I have now and get the avatars.

But also, I really doubt I'd use the full 1400 watts anyway on the 4 ohm cab. Probably more like 800 if I really thought I needed that. So that would be 400 watts per channel if I had two, which would be fine.

But then again, using 2 8 ohm cabs would be more watts than 2 4 ohm cabs. So I might as well stick with 8 ohms I guess.

billfitzmaurice · #10 02-07-2011, 01:41 PM

Quote:

Originally Posted by yadge66

It handles 2 ohms per channel, but in bridge mono it only goes to 4.

8 ohm: 275 watts per channel
4 ohm: 500 watts per channel
2 ohm: 700 watts per channel
8 ohm bridge mono: 1000 watts per channel
4 ohm bridge mono: 1400 watts per channel

All totally moot. The average 4x10 can't make use of more than 300 watts, no matter what the thermal rating is. Bridging should only be used to deliver adequate voltage swing into a high impedance load, not maximum power into a low impedance load. The more you learn the more you'll realize that watts are the last thing you should be concerned with. It sometimes seems that watts is the only thing that matters to manufacturers, and that's because watts sell. Decibels, frequency response, dispersion and everything that does matter doesn't sell gear, so they get a very short shrift.