Cabs for 2 ohm amp - a dilemma....

[xgsjx]

12 minutes ago, Dan Dare said:

It means that a good half of the population of the US believes the world to be about 6,000 years old and to have been made in 6 days, so one is advised to treat their pronouncements on anything scientific/technical with caution (Bill F is an exception, obviously).

It makes sense to take anybody's pronouncements on anything scientific/technical with caution regardless of their beliefs.

 

[Dan Dare]

1 minute ago, xgsjx said:

It makes sense to take anybody's pronouncements on anything scientific/technical with caution regardless of their beliefs.

 

Some more than others. I think I'd favour my doctor's advice over that of the man in the pub...

[xgsjx]

10 minutes ago, Dan Dare said:

Some more than others. I think I'd favour my doctor's advice over that of the man in the pub...

Does your doc know much about bass cabs?  

[totorbass]

Maybe you could swap one of your BB2's  for a 4ohm big twin, so you can use it alone with the GK, and add the 8ohm BB with the EBS to run at 2,67 ohms with a little more power, spl and dispersion, with a quite balanced load for each cab. But I don't think this "breathing" thing is very convincing. Maybe the best to do if your like your cabs is keeping them.

[Bill Fitzmaurice]

2 hours ago, Dan Dare said:

It means that a good half of the population of the US believes the world to be about 6,000 years old and to have been made in 6 days

I'd put the percentage who hold that belief to be closer to five. Don't confuse religious fundamentalism with political conservatism. Even on that the percentage of American voters who are true conservatives is nowhere near half. As with true liberals it's more like 15%. The vast majority are actually centrist, with leanings one way or another, but not strict agendas. OTOH the percentage of Americans who are numbingly stupid probably does approach half, but occasionally something happens that reaffirms the potential for hope that we still have a future, yesterdays election result in Alabama, for instance.

[Dan Dare]

6 hours ago, Bill Fitzmaurice said:

I'd put the percentage who hold that belief to be closer to five. Don't confuse religious fundamentalism with political conservatism. Even on that the percentage of American voters who are true conservatives is nowhere near half. As with true liberals it's more like 15%. The vast majority are actually centrist, with leanings one way or another, but not strict agendas. OTOH the percentage of Americans who are numbingly stupid probably does approach half, but occasionally something happens that reaffirms the potential for hope that we still have a future, yesterdays election result in Alabama, for instance.

Fair points, Bill. I've been watching a lot of Matt Dillahunty's phone ins on YouTube recently, so my view is probably unfairly jaundiced. I do appreciate that the people who call him and try to claim the man in the sky exists are not truly representative. Alabama was very good news. Well done Doug Jones.

[Bill Fitzmaurice]

Well done Black and younger female voters, those who had the most to lose if Moore was elected. I'd not the slightest who Matt Dillahunty is until reading your post. I looked him up, he's no more representative of the average American than those the polar opposites of that particular spectrum.

[Mudpup]

11 hours ago, totorbass said:

Maybe you could swap one of your BB2's  for a 4ohm big twin, so you can use it alone with the GK, and add the 8ohm BB with the EBS to run at 2,67 ohms with a little more power, spl and dispersion, with a quite balanced load for each cab. But I don't think this "breathing" thing is very convincing. Maybe the best to do if your like your cabs is keeping them.

This is my favourite option so far.  Makes a lot of sense and gives me increased options re modularity (is that word???)

[chris_b]

1 hour ago, Mudpup said:

This is my favourite option so far.  Makes a lot of sense and gives me increased options re modularity (is that word???)

In that case just buy another BB2 and run 1, 2 or 3.

[Tonteee]

To use another oft heard phrase on TB, I fear this path will lead to your amp 'releasing the magic smoke'...

[Mudpup]

:-) should be ok, its rated down to that....

[Mudpup]

9 hours ago, chris_b said:

In that case just buy another BB2 and run 1, 2 or 3.

i'll have to put more money into that option and i have coal and tangerines to buy...

[Tonteee]

 

2 minutes ago, Mudpup said:

:-) should be ok, its rated down to that....

No worries - I was aware of that - but if even the words of the venerable Mr Fitzmaurice can't convince you otherwise, I guess this is something you need to do.  Excelsior to you, sir!

[jazzmanb]

On 10/12/2017 at 18:24, Bill Fitzmaurice said:

I doubt any of them has the slightest clue what they're talking about.  What they're actually referring to is that using two cabs sounds better than one. That's the case 99 times out of 100, and it has nothing to do with the impedance load, everything to do with the increase in sensitivity when you use more than one cab. How many of them did side by side comparisons of the same amp with two 4 ohm cabs and with two otherwise identical 8 ohm cabs?

I bet you couldn't find a single one of them who's understanding of how a speaker works goes beyond 'you plug it in to an amp'.
 

Interesting stuff ,as an owner of a 2ohm Peavey 500 head which I adore I assumed I was limited in my options for "full volume " .I'm looking to ditch my two 25kg 2x10 peavey cabs for lighter options ,will I be okay looking at 2 4ohm cabs? The choice available is far greater ,thanks 

[chris_b]

10 minutes ago, jazzmanb said:

Interesting stuff ,as an owner of a 2ohm Peavey 500 head which I adore I assumed I was limited in my options for "full volume " .I'm looking to ditch my two 25kg 2x10 peavey cabs for lighter options ,will I be okay looking at 2 4ohm cabs? The choice available is far greater ,thanks 

But no one should be using their amp at "full volume". IME you'll get a better tone if you are running at a volume where the amp can handle the transient peaks, ie you need headroom for the low notes and loud bits. You don't red-line the revs in your car every time you drive anywhere and, for better tone, you should be doing the equivalent with your amp.

My take on ohms is that if your amp can handle lower figures the benefit is flexibility, not tone or volume, ie you can choose a different config of cabs without having to worry about overheating your amp. With a 500 watt amp a 4 ohm cab should be the same volume as an 8 ohm cab on a gig, because you'll be running both at the volume you need for the balance. The benefit of an 8 ohm cab is you can get a serious improvement in your tone and volume by adding another cab full of speakers not because the amp can give you an extra 100 watts when running at lower ohms.

There are several amps out there (Mesa D800) where the 4 and 2 ohm watts ratings are the same. 2 ohms is about flexibility.

[jazzmanb]

4 minutes ago, chris_b said:

But no one should be using their amp at "full volume". IME you'll get a better tone if you are running at a volume where the amp can handle the transient peaks, ie you need headroom for the low notes and loud bits. You don't red-line the revs in your car every time you drive anywhere and, for better tone, you should be doing the equivalent with your amp.

My take on ohms is that if your amp can handle lower figures the benefit is flexibility, not tone or volume, ie you can choose a different config of cabs without having to worry about overheating your amp. With a 500 watt amp a 4 ohm cab should be the same volume as an 8 ohm cab on a gig, because you'll be running both at the volume you need for the balance. The benefit of an 8 ohm cab is you can get a serious improvement in your tone and volume by adding another cab full of speakers not because the amp can give you an extra 100 watts when running at lower ohms.

There are several amps out there (Mesa D800) where the 4 and 2 ohm watts ratings are the same. 2 ohms is about flexibility.

The full volume bit was wrong ,I meant use its full potential and your add a cab comment suggests 2 4ohm cabs is the best option for a 2 ohm head ? 

[alexclaber]

The only way to use an amp's "full potential" is to plug it into about twenty 8x10" sized cabs at once. Any less than that and you're restricting the output due to a lack of speaker efficiency.

Use such a huge rig and you'll get as much output from 5W as you'll get from 500W into a more normal sized stack.

[jazzmanb]

5 minutes ago, alexclaber said:

The only way to use an amp's "full potential" is to plug it into about twenty 8x10" sized cabs at once. Any less than that and you're restricting the output due to a lack of speaker efficiency.

Use such a huge rig and you'll get as much output from 5W as you'll get from 500W into a more normal sized stack.

Why are people more interested on picking apart people's words used rather than just provide some input?it's quite clear what I'm asking .

[chris_b]

6 minutes ago, jazzmanb said:

The full volume bit was wrong ,I meant use its full potential and your add a cab comment suggests 2 4ohm cabs is the best option for a 2 ohm head ? 

No the best option for any player is the best sounding cabs at the right volume.

To carry on with the car analogies: you don't see all the Aston Martins driving about down the High Street at 90mph because that's what they can do. They all drive at the same speed as my old Volvo.

If you have a 2 ohm amp you can buy 2 4 ohm cabs but that isn't going to be noticeably different to the volume out of 2 8 ohm cabs, because the limiting factor is the level your band plays at. If a 4 ohm amp is loud enough for your gigs then a 2 ohm amp wouldn't be running any louder. At a fixed volume more speakers is going to sound much better but the ohms won't be making that difference. The 2 ohms will be letting you choose different cabs. 

 

 

[jazzmanb]

2 minutes ago, chris_b said:

No the best option for any player is the best sounding cabs at the right volume.

To carry on with the car analogies: you don't see all the Aston Martins driving about down the High Street at 90mph because that's what they can do. They all drive at the same speed as my old Volvo.

If you have a 2 ohm amp you can buy 2 4 ohm cabs but that isn't going to be noticeably different to the volume out of 2 8 ohm cabs, because the limiting factor is the level your band plays at. If a 4 ohm amp is loud enough for your gigs then a 2 ohm amp wouldn't be running any louder. At a fixed volume more speakers is going to sound much better but the ohms won't be making that difference. The 2 ohms will be letting you choose different cabs. 

 

 

Thanks for reply ,thing is with one cab (4ohm ) my 2ohm amp isn't loud enough ,it is by turning up but clips out a lot etc  . I take it that's more about the one speaker than the ohm. It's that thing with amps "350w at 4 ohms ,500w at 2ohms " which gives you the impression it's all about watts 

[chris_b]

If you're clipping it could be that you need a more powerful amp and the cabs aren't the problem at all. Have you just started using a new bass? For instance MM Sting Ray's have very hot signals which could cause clipping. You could replace all your cabs but could also add a third 210 and run the amp at 2.67 ohms. Lots of options, depending on what the problem really is.

If you like the sound of your amp then don't expect that sound to remain when you've changed the speakers. It could easily be better, could be worse, but it will be different. 

Just don't get hung up on the 2 4 ohm cab thing. 2 good 8 ohm cabs could easily out perform 2 not so good 4 ohm cabs and the best cab for you could be just one 4 ohm cab.

My 2p. . . . if you want light and powerful cabs start by checking out Barefaced. IMO they are in the top 3 cabs being made at the moment.

 

[la bam]

2 hours ago, jazzmanb said:

Interesting stuff ,as an owner of a 2ohm Peavey 500 head which I adore I assumed I was limited in my options for "full volume " .I'm looking to ditch my two 25kg 2x10 peavey cabs for lighter options ,will I be okay looking at 2 4ohm cabs? The choice available is far greater ,thanks 

I think (linked to alexs post) you would be better with say x2 4x10 at 8ohm each, rather than x2 2x10 at 4ohm each.

Even if my amp ran down to 2ohm, i dont think id ever run it at that. 4ohm is plenty.

[Lozz196]

Yep, more (good) speakers, less low end, more presence & perceived volume. I`ve found through using many amp/cab set-ups that the ones that sound loudest are the set-ups with the most actual speakers, plus the height of said speakers. Get them up to the height of an 810 and you suddenly feel you`re much louder.

[Phil Starr]

2 hours ago, jazzmanb said:

Why are people more interested on picking apart people's words used rather than just provide some input?it's quite clear what I'm asking .

I think people are trying to give you input, and from a perspective of a lot of experience. The answer to your original question is that yes you can use two 4ohm cabs with a 2ohm capable amp without problems.

Whether that is a sensible thing to do is another question. Intuitively more watts means more volume but that isn't always what you'll find in practice. The second part of your question is how to sensibly go about getting more headroom for undistorted sound at high levels. The most reliable way of doing this is to look at doubling your speakers up. Adding a 2x10 to an existing 2x10 at the same amp power will give you an extra 3dB, that's exactly like doubling the amp power. Adding a 4x10 to another 4x10 will add 3db, also the same as doubling the power so an 8x10 is going to be 6dB louder than a 2x10 using the same speakers. That's the equivalent of moving from a 300W amp to a 1200W amp. Go on adding 8x10's and your amp will eventually fill any space

The other thing is that the power supply in your amp isn't up to running at 2ohms. The power should double when you halve the ohms but in your amp it won't because it's 'engine' isn't big enough. In practice if you drive it hard at 2ohms it will heat up and become less efficient, it'll slow down on the hills to extend the car analogy.

The other thing is that volume isn't everything, it still has to sound good.

All people are trying to say is that 300W should be enough, not all speakers are equally loud but choosing wisely and doubling up is the way to go. Going down to 2ohms is usually a sign that you've started from the wrong place.

[jazzmanb]

18 minutes ago, Lozz196 said:

Yep, more (good) speakers, less low end, more presence & perceived volume. I`ve found through using many amp/cab set-ups that the ones that sound loudest are the set-ups with the most actual speakers, plus the height of said speakers. Get them up to the height of an 810 and you suddenly feel you`re much louder.

Yeah ,I have my two existing cabs sitting upright ,tall and thin .That's another concerns with small cabs ,being low on the floor  .