Bass stack ohm compatibility

[Zoomaster]

Quick question, if I ran an 8 ohm and a 4ohm cabinet (I know that would create apprx. a
2.7 ohm load) off the same head, would it produce more power going to one cabinet than the other (wired in parallel)? would the output be even, or do I need to wire them in series?

 

[David Jayne]

The 4 Ohm cab will get twice the power of the other one.

 

[Zoomaster]

Dave, is that regardless of being wired in series or parallel? Thanks

 

[DiabolusInMusic]

It is not an optimal pairing, one will see more power than the other regardless of it being series or parallel. I believe when you run them in series the one with the lower impedance sees more power but I am sure I will be corrected in the next post. I know when I ran a 4 ohm and a 5.7 ohm cabinet one saw more juice than the other so you could hear it over the other one.

 

[BassmanPaul]

In series, the 8Ω cabinet will get twice the power. If the cabinets have crossovers they could react poorly with each other.

In parallel that 2.67Ω could mean the death of your amplifier unless it's 2Ω stable.

 

[Zoomaster]

Thanks Paul, I'm aware the amp would need to be able to handle a 2ohm load. My other possibility, and what I' ll
Likely do is this: I have a carvin BR10-4, and have located a Carvin BR10-8 relatively cheap and wanted to combine
Them to make a full stack using my Ampeg SVT7pro to drive them. Since the Ampeg is rated to 4ohms I'll be
rewiring the BR10-4 to bring it up to 8ohms, since both cabs use the PS10-8 speakers, I assume the only difference
is the wiring of the speakers.

 

[walterw]

You can't re-wire a cab from 4Ω to 8Ω or the reverse, the math just doesn't work that way.

If these are both 4x10 cabs, it's just not a great pairing, there will be no good way to run them equally from the same amp.

 

[DiabolusInMusic]

If you want the Peg tone and you want to use both those cabinets your best bet is a power amp than can run two 4ohm channels.

 

[David Jayne]

What are these cabs exactly?

 

[Bottesini Bow Selector!]

If you have spare moment after answering David's question may I ask a newbie question? How should a hybrid amp 1000watt with options of 4ohm or 8ohm be connected when using 4 x10 800watts at 8ohm and 1x18 500watts at 8ohms sub together? Thanks anyone!

 

[BassmanPaul]

Despite it's popularity, mixing an 18 or a 15 with a 4x10 is a really bad idea. Either will be a weak point in your system. Neither will be able to keep up with a 4x10 in output or in sensitivity. If you really need two cabinets then identical is the way to go every time. Anything else always ends up in a proverbial crapshoot!!.

 

[Bottesini Bow Selector!]

Alas the experimenting goes on.... thanks for the tip!

 

[paulears]

The electrical and actual performance is always the problem - your two 8 Ohm cabs will produce the 4 Ohm load your amp can handle, but I too agree odd things do happen. For a bit of a project, I built a tall cab, with 15" driver and 2 x 10" drivers, because I happened to have them around. I drove them from a stereo amp. by using the controls on the amp i could blend the two. The 15" sounded deep and boomy and the 10"s clean and tight - BUT together they just sounded awful! What seemed to happen was that some frequencies would add, and stand out, but a few frets away and a note would cancel, and be dull. The two different drivers add/subtract quite destructively.