How to pair cabinets with uneven Watts?

[SouthTunnel]

Here's my deal... I have the following gear that I hand picked primarily for portability:

GB Shuttle 9: 500W @ 8ohm, 900W @ 4 ohm
Hartke HyDrive 115: 500W @ 8 ohm
Hartke HyDrive 112: 300W @ 8 or 4 ohm

I'm a wimp when it comes to toting gear. So for quieter practices I can tote my bass, the shuttle and HyDrive 112 all at one time... Win for me! Then for shows I use the 115 instead, which has casters and I can crank the shuttle without overpowering it. Easy peasy.

However without running to a PA 500W is a little light. So I'd like to figure out a way to use both cabinets with both at full power. The problem is with both cabs @ 4 ohm the Shuttle supplies roughly 450W to each. But the 112 can only handle 300W, and if I keep the volume down to prevent over powering it, the 115 is only at about half power.

Is there some trick I can do or something I can add, to be able to deliver the full 450W to the 115, while limiting the 112 to no more than 300W?

 

[morebass!]

Not with that amp. To do that you need a 2-channel amp. I don't know of any bass heads like that. Most power amps are 2 channel. But the bottom line is that your 15 and 12 may sound just fine together through your head. Try it and see.

 

[SouthTunnel]

Yeah it sounds fine. I just figure the most I could push is about 550-600W, which that incremental difference might not be worth toting the extra cabinet. I was hoping there might be some trick using an attenuator or something.

 

[SouthTunnel]

Is there another micro head that you'd recommend instead, that would address my issue?

 

[Dave W]

Don't worry about trying to get the full power from each cab. Use your ears to decide when you're pushing it too hard, then back off.

This is an issue with mixing cabs, and one of a few reasons why it's not recommended.

 

[David Jayne]

No trick. No commercially available attenuators will do, AFAIK.
But the reality is, even though you're limited by the 1x12 the pair should still be a lot louder than either cab alone. So long as you don't have cancellation issues using mismatched cabs, which is a whole other sordid topic.

 

[bassfuser]

Is there another micro head that you'd recommend instead, that would address my issue?

Genz Benz SuttleMax 12.0. It has 2 independent output sections.

 

[SouthTunnel]

Genz Benz SuttleMax 12.0. It has 2 independent output sections.

Right idea I guess. But if I understand correctly, the max it can push an 8ohm load is 375W. If the HyDrive 115 had a 4/8ohm switch like the 112 does, this would be a great solution. But the 115 is limited to 8ohms.

 

[David Jayne]

Right idea I guess. But if I understand correctly, the max it can push an 8ohm load is 375W.

Which is PLENTY. Probably more than the cab can actually handle, specs be damned.

 

[BassmanPaul]

Leaving them at 8Ω, the pair will handle a total of 600W maximum, limited by the twelve. your amp can give 900W into that load so you will have to listen carefully to the twelve for signs of distress. Stacking the twelve on the top is obvious. What you have to realize is that the power rating of a cabinet is usually the thermal maximum of the driver(s). In the real world a typical driver can handle about half of it's thermal rating before running out of excursion and into physical damage.

They could well sound good together from the stage but suffer spurious cancellations out in the room.

 

[daveman50]

Leaving them at 8Ω, the pair will handle a total of 600W maximum, limited by the twelve. your amp can give 900W into that load so you will have to listen carefully to the twelve for signs of distress. Stacking the twelve on the top is obvious.

What he said. -- you will blow the 12 before the 15 - just use your ears and common sense - if you hear the 12 farting, back off - don't expect to use all of that 900 watts - not even close.