Questions about using 2 cabs.....

FarleyUK

Hi guys,

I have a question (on behalf of my bassist) about using a couple of cabs with a single bass amp....

He's just purchased an Ashdown Rootmaster RM420, along with 2 cabs - a 4x10 RM-MAG-4101 and a 1x15 RM-MAG-115. From what I can see, the cabs and the amp are all 4 ohms (although looking online, it seems the cabs are 8 ohms...??).

I have a couple of questions that would be great to get some answers to....!:

1) Out of the two cabs, whcih would be considered 'better', and why?

2) How could we connect the 2 cabs to the single amp to be able to use both of them together?

Thanks all!

ICBM

FarleyUK said:

He's just purchased an Ashdown Rootmaster RM420, along with 2 cabs - a 4x10 RM-MAG-4101 and a 1x15 RM-MAG-115. From what I can see, the cabs and the amp are all 4 ohms (although looking online, it seems the cabs are 8 ohms...??).

I have a couple of questions that would be great to get some answers to....!:

1) Out of the two cabs, whcih would be considered 'better', and why?

2) How could we connect the 2 cabs to the single amp to be able to use both of them together?

You connect them to the amp with a speaker cable each - according to the spec it has two output jacks. *Not* guitar cables…

According to the spec the cabs are 8-ohm, which is what all Ashdown cabs I know of are so that sounds right. The idea is that you can use one or both with the amp, giving a combined load of 4 ohms when both are in use… although looking at the spec, I would be careful running just the 1x15 alone, it may not be capable of taking the full power of the amp even though it will be less at 8 ohms than 4 - Ashdown 15s are very easy to blow in my experience. The 4x10 should be fine, even alone.

Using the 15 as well should give you more deep low-end and better dispersion through a space than just the 4x10. You will definitely get more power with both cabs connected, so in theory you should need to turn the amp up less far for the same final volume - but running the amp with both cabs will strain it more if it's really cranked up, and Ashdowns are notoriously unreliable with this sort of use, so I would try to use it for a fuller sound rather than more volume - although I haven't seen a dead Rootmaster yet so possibly they're better than the older ones.

Confused, or does that help?

FarleyUK

That helps, thanks!

However, it only has one output for speakers..... Unless you mean the DI?

http://www.fullcompass.com/common/products/original/207753.jpg

ICBM

FarleyUK said:

That helps, thanks!

However, it only has one output for speakers..... Unless you mean the DI?

No - you're right, it only has one speaker out, which is a Speakon. The spec says two jacks…

Speakon is better, actually - higher current rating and locks into place. Does either or both the cabs have two Speakons, or a Speakon and a jack? If so, connect the amp to the top cab with a Speakon cable, and the top cab to the bottom cab with another Speakon cable, or a jack cable if they only have one Speakon plus a jack.

If they only have one input at all, you'll need a splitter of some sort.

FarleyUK

He's got a speaker cable, not a Speakon - but both cabs have a Speakon and a jack. Would setting them in series be OK for this then? No danger of blowing anything up?

Cheers!

ICBM

FarleyUK said:

He's got a speaker cable, not a Speakon - but both cabs have a Speakon and a jack. Would setting them in series be OK for this then? No danger of blowing anything up?

They're not in series - the jacks in the cabs are paralleled.

The amp only has a Speakon so you must use that to get the signal out of the amp - and it's really necessary at 420W @ 4 ohms anyway. Connect that to the 4x10", then connect the 4x10" to the 1x15" with a jack cable - it only needs to handle half the current so it will be fine. So all he needs to buy is a Speakon cable.

FarleyUK

ICBM said:

FarleyUK said:

He's got a speaker cable, not a Speakon - but both cabs have a Speakon and a jack. Would setting them in series be OK for this then? No danger of blowing anything up?

They're not in series - the jacks in the cabs are paralleled.

The amp only has a Speakon so you must use that to get the signal out of the amp - and it's really necessary at 420W @ 4 ohms anyway. Connect that to the 4x10", then connect the 4x10" to the 1x15" with a jack cable - it only needs to handle half the current so it will be fine. So all he needs to buy is a Speakon cable.

Done - ordered the Speakon cable for him today, ready to test it at the gig on Friday

Thanks very much!