Help!!! Need advice on cabs and ohms

[Thestonekid]

Hello all!
I have a question for you more experienced player out there...
I have a GK Backline 600 head
I play through a GK BLX 410 cab. I've seen a BLX 210 for sale that I'm thinking of getting. Will this make me louder? Will it still be OK to run my amp with without damage??
Thanks.

[bonzodog]

As long as the amp is 4ohms and both cabs are 8ohms which I am pretty sure they are then you will be fine. Using both will mean you are getting full use of the amp but don't expect the volume difference to be hugely different to just the 410 on its own.

[Thestonekid]

Great. Thanks for advice!!

[CamdenRob]

Other more knowledgeable answers to follow I'm sure, but as I understand it you're better off having matching cabs even if you can make it work with the impedance... half the power would be going to the 210 and half to the 410 which might sound a little unbalanced?

But it would be louder as you have more speakers moving more air.

[Thestonekid]

Well the 410 is 400w handeling and the 210 is 200w handeling.. Does this make a difference??

[Dad3353]

[quote name='Thestonekid' timestamp='1463399901' post='3050980']
Well the 410 is 400w handeling and the 210 is 200w handeling.. Does this make a difference??
[/quote]

The amp develops 300w into 4 ohms, of which (at full tilt...) 150w will go to each cab. Both should be fine, in theory; you'll hear if there's a problem, probably. At that rate, your ears will be singing, however.

[Lozz196]

I`ve done the same, an 8ohm 210 and an 8ohm 410. Worked fine, and the benefit of having the 210 on the top is you can hear if it struggles. As Dad says though, your ears will no doubt be dealing with their own issues if that happens.

[Thestonekid]

Great. Thanks people.. I'll update and let ya know how I get on.

[JTUK]

[quote name='Thestonekid' timestamp='1463399901' post='3050980']
Well the 410 is 400w handeling and the 210 is 200w handeling.. Does this make a difference??
[/quote]

Yes, IMO... as the lower powered cab gets half of the amp output if the impedence is 8 ohm per cab.

I'd say 200w of bass is a tough ask ... but how do you know what output you are pushing..?

So, the only option is to use your ears and at those levels you might not hear it all in time..before damage of the chassis has occurred.

So, my own adage is to have the output balanced across the cabs ( impedence-wise) and MORE cab than amp...IME.

[Thestonekid]

God, I'm starting to wonder if it's a good idea to buy the 210. I'd prefer a 115 without doubt but I can't find them around.. My band is bloody loud and I thought the 210 would just give me that little bit more... Now confused...argh!!!

[obbm]

Just get a second 4x10. Job done.

[machinehead]

Yep, a second 4x10 is the way I'd do it. The 1x15 would be a bad match.

Frank.

[Bolo]

Tilt your cab up a bit so it doesn't blow against your legs but at your head, and tell the other sobs to turn the f*** down.

Adding a 410 might be easier to achieve; )

[chris_b]

IMO 10's would sound better with your 410 cab.

The Backline 600 head is only 300 watts. A bit of marketing liberty taking if you ask me.

If your 410 is 8 ohms then your amp, running at 8 ohms is putting out about 150 watts. If the cab is rated at 400 watts then you'll be safe putting your 150 watts into it.

You could get a more powerful amp but you'll hear more volume by adding more speakers than by adding more watts, so adding a 210 will be fine. Another 410 might be overkill or just right, depending on how loud you really are. I'd go for the 210 option.

And just in case you really are that loud. . . . get some good ear plugs.

[TimR]

Forget about the power. That's just what the speakers can take without catching fire.

Look at the sensitivity figures.

The frequency plots for the two cabs will undoubtably be different. It's not all about all out power. So you can expect all kinds of weirdness going on.

As alluded to above. If you're not loud enough with a 4x10 something is wrong with either your EQ or your cab placement.

[BottomE]

Should be fine. I have an 8ohm 2 x10 and and 8 ohm 2 x 12 fed by my amp - MONSTER sound. Enjoy the power

[AndrewJordan]

[quote name='Dad3353' timestamp='1463408050' post='3051086']
The amp develops 300w into 4 ohms, of which (at full tilt...) 150w will go to each cab. Both should be fine, in theory; you'll hear if there's a problem, probably. At that rate, your ears will be singing, however.
[/quote]

I don't think thats right. If both cabs are eight ohms and both cabs are conected in parralel then the power will be divided equally between the six drivers. So, I am guessing the drivers can take 100W each from what you have said. In that case each driver will be getting 50W from the head which would be well within the safe zone provided you are not constantly clipping the amp in an effort to make it louder.

I would expect you to hear a reasonable volume increase from both the extra drivers and the extra power that that lot will create.

[TimR]

No. It is right. The individual speakers in the 4x10 will be a different impedance to the speakers in the 2x10.

Each can will present the same load - 8 ohms and the same power will be dispersed in each.

.

Edited May 19, 2016 by TimR

[chris_b]

[quote name='AndrewJordan' timestamp='1463664393' post='3053203']
I don't think thats right.
[/quote]

It is.

If the 410 was 4 ohms and the 210 was 8 ohms then you would be right. Although this set up would have to be run by an amp capable of 2.67 ohms.

With 2 8 ohm cabs the power is divided equally between the cabs. In this case the smaller cab is potentially the weak link so as long as the 210 can manage the power being sent to it there is no problem.

[Dad3353]

Yes, the 4 x 10 cab and 2 x 10 cab will absorb the same power. At full whack, each 4 x 10 speaker (yes, I'm that old...) will be taking 150w/4 (37.5 each), the two in the 2 x 10 will each have 75w to dissipate. As each speaker is rated at 100w, in theory there should be no problem. That, however, is roughly where the maths runs out and the ears (and brain, listening...) come in. You'll hear if there's a problem.

Edited May 19, 2016 by Dad3353

[AndrewJordan]

My bad! You are all correct. I was thinking all the drivers would be 8ohm but of course the 2x10s can't be. Serves me right for not thinking it through properly.

[BassTractor]

The point that is being made by those who advise to double up with the same types of cab, though I haven't seen that point outspoken in this thread, is that the impedance is a nominal number and that the "real" impedance differs, a.o. with frequency, so the behaviour of the different drivers in combination can not easily be predicted.
An impedance raise in one cab at the same frequency range as an impedance drop in the other cab might cause some of the drivers to travel too near their Max.
Here's where you need to use your ears.
Normally you should be reasonably in the clear as long as you don't press your drivers hard.
Sound quality is another matter.

Me, just to be sure to not blow my drivers, I use a 9610, and our drummer likes the notion of being able to pick his nose without anybody seeing it.

Edited May 19, 2016 by BassTractor

[TimR]

[quote name='BassTractor' timestamp='1463681058' post='3053365']
The point that is being made by those who advise to double up with the same types of cab, though I haven't seen that point outspoken in this thread, is that the impedance is a nominal number and that the "real" impedance differs, a.o. with frequency, so the behaviour of the different drivers in combination can not easily be predicted.
An impedance raise in one cab at the same frequency range as an impedance drop in the other cab might cause some of the drivers to travel too near their Max.
Here's where you need to use your ears.
Normally you should be reasonably in the clear as long as you don't press your drivers hard.
Sound quality is another matter.

Me, just to be sure to not blow my drivers, I use a 9610, and our drummer likes the notion of being able to pick his nose without anybody seeing it.
[/quote]

I raised that point yesterday at 4:40pm.

[BassTractor]

[quote name='TimR' timestamp='1463692674' post='3053483']
I raised that point yesterday at 4:40pm.
[/quote]

Aye, you did. But then I didn't state you hadn't done so. I just stated I hadn't seen it.
Sorry for having overlooked it.

[CamdenRob]

[quote name='AndrewJordan' timestamp='1463674631' post='3053302']
Serves me right for not thinking it through properly.
[/quote]

Don't worry about that... if I thought everything through before posting I'd never post anything...

I notice I've recently passed 4000 posts and at least half of that is nonsense.