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Using cabs with a Combo?

T

TheRockinRoadie

May 22, 2009
454
3
Cambridge, UK
www.facebook.com
#1
Hi There,

I know this is really a FAQ question, but i couldnt find anything directly related to what i want to know.

I have an Ashdown Electric Blue 180W 1x12" combo, and it has an extension cab output (i have been told to use an 8ohm cab). I would like to use the Ashdown MAG 1x15 deep cab, which has an 8ohm rating, and 150W power handling. So my first question is, if i use the cabinet with my combo, will it kill the speaker in the cab?

Which leads me to my second question:

When you add cabinets together, do you add their power handling together to find out your maximum power?

Eg. 150W/8ohm cab + 200W/8ohm = 4ohms @ 350W?

Cheers in Advance for any help,
Lorry :smug:
 
#2
Dont know about the first part but

You've got the ohms right.

Basically 2 8s becomes 4.. etc.

And when you do that, you take your 4ohm wattage and half it, thats the load to each cab.

So you could have 300W @ 4ohm to max it out.

200W just to be safe, I think you're fine on the wattage load
 
#3
you will need a cap with 180W at least. the mag 1x15 with 150w power handling could be damaged if you crank the volume up.

combo+cabinet= 4 ohms
you will have to check the ashdown website, how much power you will get with your combo at 4 ohms. if you get 350W (i think it wont be more than 300W), you should have a cap that is at least able to handle 300W
 
#8
TheRockinRoadie said:
Hi There,
<snip>
When you add cabinets together, do you add their power handling together to find out your maximum power?
Eg. 150W/8ohm cab + 200W/8ohm = 4ohms @ 350W?
<snip>
Click to expand...

Almost. Since two cabinets of the same impedance will split the power sent to them evenly, you should assume twice the power of the lowest power capable speaker. In your example, one of the cabinets can only handle 150 W @ 8 ojms. Therefore, you would want to look at the system as being capable of handling 300 W @ 4 ohms, since half of the power will be sent to each speaker. If you send it 350 W @ 4 ohms, then half of that, 175 W, would be sent to each 8 ohm speakers.
 
#9
FWIW.......I have the Ashdown EB180 with the 15" speaker. It is an 8ohm speaker. The extention cabinet I use is an Ampeg 410HE, also 8ohms. Total load=4ohms.
The EB180 is rated 180 watts into a 4ohm load. Using only the internal speaker, I assume it makes about 100 watts.

Ken R
 
#10
Ken R said:
FWIW.......I have the Ashdown EB180 with the 15" speaker. It is an 8ohm speaker. The extention cabinet I use is an Ampeg 410HE, also 8ohms. Total load=4ohms.
The EB180 is rated 180 watts into a 4ohm load. Using only the internal speaker, I assume it makes about 100 watts.

Ken R
Click to expand...

i think i read somewhere on here that the electric blue actually puts 120 watts into 8 ohms... then again the same post claimed that the internal speaker had an impedance of 6 ohms (dubious) :confused:

i guess it really doesn't matter though
 
#14
NOTE to folks lurking. (and considering extention cabs)

Call your MFG (or read the manual) arbitrarily manufacturers expect you to disconnect (turn off etc) the internal cabinet when running to others.

The unfortunate thing is that they don't silk screen detailed instructions.

Music stores rarely have folks that understand ohms and ratings with regard to the amp.

IF your ohms go too low basically you can overheat your power amp.

Do your homework before creating damage.

Tim
 

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