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I woke up this morning asking this question!

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R

RIjake

Nov 10, 2007
81
0
New England
#1
First off Merry Christmas all!

OK, now I know some folks here get a little testy when newbies (such as myself) ask questions that have been answered before so let me just say that I've done an exhausting search (IvanMike great stuff!)for this question and frankly can't believe no one has asked it before so feel free to direct me to a previous thread if it exists.

At what point are the speakers rated too much for the amp? IOW does the amp have to be matched wattage to the cabinets?

Let me get specific. I've got a GK 400RB-IV, 280 w @ 4 ohms. I've got an Avatar 2x10 cab rated at 500 w @ 8 ohms. I purposely bought the 8 ohm so at a later date I could add another 8 ohm cab (maybe another 2x10 or a 1x12 or 1x15)

Is it a "waste" to have one or more 500 w cabs being driven by a 280 w head?

If I have (2) 500 w, 8 ohm cabs am I now trying to push 1000w with a 280 w head?

Do you see where I'm going with this? Did I make a mistake by going with a 500 w cab?
 
#2
There are 2 ways to answer your question, one involves all the science/physics (which I understand but it'd be quicker for you to Google it or search the forum) the second is the real life answer... I'll do the latter!

No, you have not made a mistake it is fine. Most cab ratings are woefully inaccurate anyway but one thing you do have to consider and bear in mind is the sensitivity of your cabs (measured at 1w 1m and normally quoted in the specs with a figure somewhere between 90+db and 105db). What you need to avoid is driving your amp too hard to get the desired volume from your cab, when this happens you get clipping/distortion and that ain't so good. The higher the sensitivity rating of the cab the easier it is for your amp to drive, a low figure means that you 'generally' require more watts to get it up to the desired volume.

If your amp and cab are giving you the volume that you require and neither is complaining then it's a good match :)
 
#5
I push 300 watts through a pair of cabs rated at 800 watts and 600 watts, and it sounds great. I can run the amp hard, and the speakers never run out of room to take it. Therefore, you're set up is also fine, no worries of blowing your speakers, as long as you don't do anything foolish.
 
#8
One way to think about it that simplifies it a little: the speakers aren't trying to pull watts from the amp, they take what the amp gives them. So, as the other posters have said, if your speakers are rated for more watts than your amp, all good. If your amp pushes more watts than your speakers are rated for, not good.
Warwickhunt's point about sensitivity is good info, but unless Avatar uses an unusually inefficient design it's probably not an issue for you. Larger cabinets are most often more efficient than smaller ones so you probably haven't hurt yourself there either.
 
#14
If you are fine then I guarantee you have not actually been using all 2000 watts, no matter what the label on the front of the amp says. In real-life application, most amps use only a tiny percentage of their wattage during the times the player is not playing big hits on the low strings.
 
#16
The only think that "could" happen is that you Clip the amp.
If the amp clips it can hurt the speakers no matter what wattage rating either are at.
So a 50 watt amp cliping itself into a 500 watt speaker cab can blow the head and or speakers.
Jonathan
 
#19
JonathanD said:
The only think that "could" happen is that you Clip the amp.
If the amp clips it can hurt the speakers no matter what wattage rating either are at.
So a 50 watt amp cliping itself into a 500 watt speaker cab can blow the head and or speakers.
Jonathan
Click to expand...

That isn't really the case, but I don't have time to go into why right now. It has been explained a bunch of times on here by folks like Bob Lee (QSC), Bill Fitzmaurice, Jerrold Tiers and myself (all audio professionals, BTW, for what it's worth) , so you should be able to find lots of dialog on the subject if you search "clipping" or "underpowering" on the site. I'm normally happy to discuss the subject but I need to get off TB and spend some time with my family. :)
 
#20
With respect to the science of amp vs. speaker, I offer a different alternative: use your senses. Learn to really "listen" to your rig. Teach yourself to recognize distortion and why it's there. There's good distortion (e.g. tube and effect) and bad distortion (e.g. SS amp, speaker). However, that can be debated. :) Once you hear something going on in your rig at stage volume, that shouldn't be there, you can quickly diagnose it and adjust accordingly. Also, I believe that amplifier heat should be monitored. Heat is one way to quickly monitor how your amp is handling the load. If your amp and speaker are getting along with respect to, at the very least, these ideas, then you probably have a good rig.
 
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