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cab/ohm/power amp question

S

skunkrawk

Apr 25, 2003
194
0
38
DC
#1
ive seen alot of threads asking similar questions and i still cant get a clear answer in my head (sorry). i soon hope to order an avatar 2x12 and an avatar 2x10. id power them with either a carvin dcm 1000 or one the the qsc rmx series poweramps and use a tech 21 sansamp rbi pre (i cant decide whether to get carvin or qsc :hmm: ) the question is should i get 4 ohm cabs or 8 ohm cabs? thanks! -dave
 
#2
How do you plan to use your power amp of choice...parallel input (one cabinet per channel) or bridged (both cabs on one output)?

If you'll dedicate a channel to each cabinet, 4 ohm cabinets would allow you to get the most power out of the power amp. If you're going to bridge, then 8 ohm cabinets are the only choice as these amps can't bridge into 2 ohms (two 4 ohm cabinets in parallel present a 2 ohm load to the amp...two 8 ohm cabinets in parallel present a 4 ohm load to the amp).

Does this help?
 
#4
Not really better or worse...just different.

If you run parallel inputs, you can control the volume of each cabinet individually at the expense of less total power being available (if the two power amps put out their max wattage at 2 ohms per channel...and I believe that they do, but I didn't look) because you'd only be able to run each channel at either 4 ohms or 8 ohms.

Bridged, you only have one active volume control, but you'll get maximum power out of the amp when bridged into a 4 ohm load (two 8 ohm cabinets in parallel).

Volume wise you might not even hear a difference.
 
#9
and just a reminder
running an amp at 2 ohms creates more resistence on the amp making it work harder and also creates more harmonic distortion.


I actually just got to use my new rig (close to yours) tonight at practice, and it was spectacular. after the first two hours of playing my rig, the neighbor complained! splendid!

my gear:
QSC PLX 1602 (QSC I think is avery durable brand)
Tech 21 SansAmp rbi
I'm running two 8 ohm GS112s in parallel mode and its putting out a ****load of sound.

I have an equalizer I haven't hooked up yet and a dbx 160a compressor in the mail.

david
 
#11
Originally posted by amos
and just a reminder
running an amp at 2 ohms creates more resistence on the amp making it work harder and also creates more harmonic distortion.
david
Click to expand...

Just another reminder.

If the amp is designed to handle 2 ohms, there's no problem whatsoever. It will run a little hotter, but hey, go figure, it's putting out more power!

And with today's amps, harmonic distortion is practically non-existant to begin with, even at full load and full power. And I doubt you or anyone would be able to descern between 0.001% and 0.1% of THD, let alone if you're playing at 110dB+ sound pressure levels.

Just my E0.02
 

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