cab question (technical)

[Geek99]

Hi, I read the pinned threads but couldn't find the answer.
Been looking at ebay for rigs and noticed that cabs are often miced wattage.
If an amp is 300 watts at 8 ohms and the two cabs are 400w (4 x 10 perhaps)
and 200w respectively how is it that the 200w doesn't start distorting when you turn it all up?
Surely its 'outclassed' by the amp ? Please assume cabs are both 8ohm for sake of argument.
Thanks

[deksawyer]

Because the 300w from the amp is 'shared' between the 2 cabs equally, if they're have matching impedance.

Also, for the sake of argument, you can't often run 2 x 8 ohm cabs into an amp which can only handle 8 ohm, as the usual load with both cabs combined will be 4 ohm. Having said that, there's not a lot of amps out there that only work at 8 ohm - usually combos.

D.

[chris_b]

[quote name='Geek99' post='628531' date='Oct 17 2009, 09:47 AM']....cabs are often miced wattage. If an amp is 300 watts at 8 ohms and the two cabs are 400w (4 x 10 perhaps) and 200w respectively how is it that the 200w doesn't start distorting when you turn it all up? Surely its 'outclassed' by the amp ? Please assume cabs are both 8ohm for sake of argument....[/quote]
I have never heard of "miced wattage"!

If I've unravelled your post right, if the amp is rated at 300 watts max power, that will usually be at 4 ohms, making it about 200 watts at 8 ohms.

Both cabs will have to be 8 ohm (don't mix 8 ohm and 4 ohm cabs unless the amp can handle 2 ohm loads).

So 1 cab will see approx 200 watts and 2 cabs see 300 watts, but out of that 300 watts each cab will see 150 watts.

So you can't "over power" either cab, but you can get a nasty distorted sound by turning most amps "full up". So don't do that! If you're going to use one cab make it the 400 watt cab.

I'm sure we have better rigs in the Basschat For Sale section though!!

[warwickhunt]

Aside from the above (and various other factors), the rating on most cabs is a load of shyt so you can to some degree almost ignore it. As has been stated above you will 'hear' when things aren't right.

There are folks on here who will run 200w amps into 1000w cabs and there are folks who will run 1000w amps into 200w cabs and I can assure you they can both be done quite safely; [u]if you use common sense and your ears[/u]! Conversely there are folks here who can destroy a cab and/or an amp that is supposedly perfectly matched.

[Geek99]

Chris-b there are lots of rigs for sale with mixed wattages, prompting my question. Deksawyer pretty much answered it although I still wonder if a shared 300 watts out of the amp means yioure not getting value out of the 400 watt cab.
Thanks to all

[chris_b]

[quote name='Geek99' post='628702' date='Oct 17 2009, 01:38 PM']....there are lots of rigs for sale with mixed wattages.... although I still wonder if a shared 300 watts out of the amp means yioure not getting value out of the 400 watt cab....[/quote]
What "value" are you trying to get? You don't really want to drive your gear to 100% and you won't get the best tone out of it if you did. I put 100-200 watts (out of a possible 300 watts) into my Epifani 1200 watt cab (8 ohm) and get a great sound or 100-200 watts (out of a possible 500 watts) into my 2 Bergantino cabs (4 ohm) and get an even better sound but I really don't play much louder! Good tone is the value that I would be aiming for. This is very unscientific, but I only aim to run my gear in the region of half its capabilities. Good tone is the cleaver bit, Watts/power is cheap and I don't want to stress any part of my gear. This is just my take on gear; others may have a different view.

[Mr. Foxen]

Basically, the watt rating of a cab is pretty much totally irrelevant to everything. There is much more to what can break a cab than that, and they all share the symptom of making the cab sound very bad first.