175W amp & 300W cabinet, too underpowered?

[Richard Lindsey]

Thanks for all the replies!

A few folks have mentioned getting another cabinet in addition to the GS112. I don't have the money at the moment, but I'm curious as to how such an arrangement works.

I'm confused about how the second cabinet's power requirements come into play. If I have two cabinets at 300W @ 8ohms and the single head I have now, how does that head put out enough power? What's the difference between one and two cabinets -- if I can power two cabinets with one head, why can't I give more power to a single cabinet?

(You can tell that I don't know much about this stuff. )

Your basic misconception is that the ratings on cabs are, as you say, "requirements," as if they "needed" that amount to work properly. They're not--they're the maximum amount that the cab is supposed to be able to handle. IOW, they are upper limits, not lower limits.

You'd think that giving 200 W to a single driver would be the same as giving 200 W to two of the same drivers (100 W each), but it's not. The same wattage into more drivers, assuming all else is equal, gives you more volume. There would be little reason to use multiple drivers otherwise.

 

[NWB]

Just to think that if "underpowering" was a cause of speaker failure, then everytime you ran even a higher-powered amp at quieter levels, you'd start blowing speakers.

For example, running a 1,000 watter at something around 1/8 volume setting and it's putting out, let's assume 200 watts at that level, into a cab rated at an assumed 800 watts. Will the drivers melt, explode, rip, or fail in any manner?

I think not.

If the underpowering myth had any validity, then we'd all have to dime our amps all time just to keep from blowing speakers.

 

[Sten]

Thanks for all the replies!

A few folks have mentioned getting another cabinet in addition to the GS112. I don't have the money at the moment, but I'm curious as to how such an arrangement works.

I'm confused about how the second cabinet's power requirements come into play. If I have two cabinets at 300W @ 8ohms and the single head I have now, how does that head put out enough power? What's the difference between one and two cabinets -- if I can power two cabinets with one head, why can't I give more power to a single cabinet?

(You can tell that I don't know much about this stuff. )

With your one 8 ohm cab, your amp puts out 175W. With two same cabs, you have an impedance of 4 ohms and your amp puts out 300W, leaving 150W for each cab. This means, one cab gets only a little less power, but you have twice the speaker area! It will be a lot louder.

If you then want to even go a step further, with Shuttle 6.0 you can already push 300W to each cab.

This is a way to go louder step-by-step if you need to If you are satisfied with your volume without really pushing your amp, then there is no need for additional cabinet. If your volume is usually turned past 12 o'clock, then a second cab would be recommended.

 

[Sten]

And you CAN give more power to one cabinet if it was 4 ohm (your current setup pushes the cab with 175W as said, 4 ohm would recieve 300W). Still it's not only about power, doubling speaker are increases the volume significantly!

That said, with second 8 ohm cab, you increase both speaker area and total output power!

 

[Kelly Lee]

This topic is covered extensively in the FAQ's thread stickied at the top of the Amps forum.

Closed.