Adding a third cab...

[Rob Stevens]

Hello to 'the collective'...

New member here!

I have a pair of Trace Elliot 1x10''cabs (8ohms each but connected are 4ohms?) and am thinking to add another to make 3.. The amp head would be an Aguilar AG 500 or 700, which does have the capability to run @ 2.67 ohms, which I understand is what I would need? So: Looking to confirm what I think is true. But questions:

 

Is it a good idea?

Will it sound as good as with 2 (but just 'more?)

The cabs are rated @300w each, so the head is well within that as the feed is split 3 ways, is that correct?

I don't understand the physics of ohms and watts and volts etc.. Is it that lower ohms is easier or harder for the amp to work properly?

Is it an issue for a modern amp head? Will it not deliver as it should, or get hot, or distort etc..? Or something else?

 

Thank you for your guidance. Regards. 

Rob

 

[BassAdder60]

Yes three 8ohm cabs would result in 2.67ohms load which if you set your amp to that should be fine 

 

Each speaker will receive a 1/3 power each and assuming all the same spec. cabs will sound balanced 

[Dan Dare]

I often run three 8 ohm cabs with an AG700 and it works well. It isn't so much louder as fuller sounding.

 

As a general rule, running an amp into too low an impedance can cause it to overheat because it's being required to deliver more current than it is capable of providing. At low volume levels, it probably won't be an issue, provided the amp is adequately cooled and you aren't asking it to drive 1 ohm or similar. A low impedance load is easier for an amp to drive up to a point, but it's when you push things that problems can arise. Many modern amps have some sort of protection circuitry, which will shut down or mute them if you try to overdrive them.

 

Obviously, you'll need to let the amp cool and address the issue that caused the shutdown before continuing. You're also likely to notice the sound gets dirty prior to the amp shutting off. Of course, if you like a dirty/over-driven sound, you may not notice that until there's a problem.

Edited Tuesday at 14:22 by Dan Dare

[Rob Stevens]

Thank you both.

Good not to hear that my idea is 'not the best' and that it can be done, cos Dan does it...!

Also good to hear that the sound is 'balanced ' and 'fuller tone' which is what I'm after rather then out and out volume...

 

Spooks me a bit to hear about the heat issue..... And that it can be a problem. The specs say it has 2 cooling fans, but I won't be driving it to high levels since my music room is quite small.... so I guess I'll be OK with that too.

Regards. Rob

 

[Bill Fitzmaurice]

FWIW most of the improvement is the result of the third cab being closer to ear level, allowing the mids and highs to be more easily heard. You can come close to the same result with a stand. So long as it's less than 70cm high there's no loss of bass coupling with the floor.

[Dan Dare]

3 hours ago, Rob Stevens said:

Spooks me a bit to hear about the heat issue..... And that it can be a problem. The specs say it has 2 cooling fans, but I won't be driving it to high levels since my music room is quite small.... so I guess I'll be OK with that too.

 

You don't need to worry, as your amp is rated to drive 2.6 ohms. Unless you really cane it (in which case, you're likely to notice because it will distort), you'll be fine. An amp will only overheat if you try to drive a lower impedance load than it can cope with. There's a safety margin before issues crop up - the impedance of all speakers varies with frequency and the stated impedance is an average. You'll only have problems if you really push things.

[Bolo]

Or get a 210 for even more flexibility?

[Dan Dare]

1 hour ago, Bolo said:

Or get a 210 for even more flexibility?

 

That'll likely be 4 ohms, which could cause impedance issues when combined with the others.

[chris_b]

Do 3 cabs sound better than 2?

 

Well you are moving more air, so if that air sounds good, more will probably sound better.

 

In my case, I used to run 1, 2 and 3 Bergantino AE112's, depending on the band and venue. 2 cabs sounded great, but 3 sounded better and was my favourite config. 

[Rob Stevens]

Again . Thanks to all for your input.

Dan's reassurance that my compatibility worry is unfounded.

Bill, I currently have my 2 on a small stand to elevate them....! Thanks. I also think it looks better.....

Bolo, I have 2 10's now so adding another 2x10 would give me 4, and I don't want 4. That would probably blow my windows out if I let it... But thanks anyway.

Chris. My thinking is to have exactly what you are endorsing.

 

Oh and as an aside. Dan....  Are you from Wisconsin...?

Regards. Rob

[Dan Dare]

1 hour ago, Rob Stevens said:

Oh and as an aside. Dan....  Are you from Wisconsin...?

 

No. London. "The Hog County" is an old nickname for Hampshire, where I live now following my retirement.

[Bolo]

7 hours ago, Dan Dare said:

 

That'll likely be 4 ohms, which could cause impedance issues when combined with the others.

A quick google tells me there's no shortage of 8ohm 210s.

It could yield a 110, 210, 310 or 410 configuration for any size room or stage together with the current cabs. Possibly more convenient to carry too.

 

I like 12 inchers myself.

[Downunderwonder]

An 8 ohm 210 would be a mishmash of drivers that would not be appreciably louder than the 310 stack. They would only be getting a half share of power each in the 210.

 

Tonally there would be no idea what is going to eventuate until tested.

 

Stick to te 310 plan.

 

But for home use I can't see the need.