duh...help with amp & cab wattages & what nots

There is no 200W being wasted. The 600W rating on the cab is just how much it can safely handle under typical operation.

Again, that number does not mean anything at all--each cab is rated for how much it can handle, which has zip to do with how much wattage each of them is receiving at any one time, and those handling ratings cannot be added together. One cab can still only handle 400W, and the other can still only handle 600W. And actually, those numbers are just nominal indications to give you a general idea of what's safe, they don't actually describe a "literal reality" in all circumstances.

No, first and foremost because the idea that a 15 will improve bottom end is very often incorrect; also because that cab can only handle 200W safely, completely regardless of what the Ashdown has to offer.

The outputs on your amp and on your cab are all parallel, regardless of how you cable them together.

 

You have got to remember that power is not the only thing at play here. You have cabinet efficiency to take into account. If the GB is more efficient it will appear louder than the Ashdown when run in parallel. Had you been running a pre/power rig you could have balanced the volumes out using the channel level controls.

Paul

 

Efficiency is given by many manufacturers as "sensitivity" in the specs; unfortunately those specs are often wildly misleading. So in practical terms it's best to research the efficiency of a given cab from actual users, relying on their subjective impression, rather than relying on the spec provided by the manufacturer. However it may sometimes still be worth your time to look at the spec, just in case there is a really obvious mismatch.

"Volume" is much more than just wattage and ohms. Volume is a combination of many factors, including EQ, efficiency of the speaker driver, efficiency of the cab tuning, etc. etc. If we're saying "all else being equal", where the 4 ohm and 8 ohm cabs were in all other ways identical, then the 4 ohm one would receive more wattage from the amp than the 8 ohm one would. When an amp is rated for a certain wattage at 4 ohms and a certain amount at 8, that is the "automatic" relationship between that amp and that speaker load.

Your amp generates more wattage when the total load connected to it is 4 ohms, compared to when the total load is 8 ohms. When "all else is equal", more wattage will normally mean more volume, unless there is some other limiting factor in the chain.

Note however that just as speaker wattage ratings are just a general upper limit they can handle, amp wattage ratings are not a literal description either, as the actual amount of wattage you put out while playing is typically a lot less than the rated amount, but with occasional spikes at or exceeding the rated amount of watts.

 

You got some really great anwers here. If you want to increase your volume, I would recommend to get a second Ashdown cab of exactly the same model. Matching different manufacturers, models and driver sizes can lead to unpredictable results. Since you liked its low end, It would fit you great I bet.

If you are happy with the volume you are getting from one Ashdown, there is no need though

 

Great responses so far.

Also (didn't see this mentioned), when you went from one 8-ohm cab to two 8-ohm cabs, you created a total 4-ohm load, which is shared between the cabs.

So you went from 400w available for one cab, to ~337w available for one cab (x2). This may partially account for the volume drop in one of the cabs, depending on the efficiency of the speakers/cab (as described earlier).

 

Theoretically, no, the 4-ohm cab will be louder since it's drawing more power from the amp. To get the most volume from your particular amp, you would use two 4-ohm cabs to draw the full power @ 2-ohms.

 

You could do that, but the 4ohm cab will receive double the power of the 8ohm cab- 500 watts will be drawn by the 4ohm one and 250 by the 8ohm one. You may or may not find this to be a problem. It's definitely best to apply equal power to all of the speakers, and to use two identical cabs.