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Dual Voice Coil Speaker Amp Question
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RAILhead
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Aug 16, 2010, 12:47 PM
 
I'm getting mixed answers to a question I have regarding a dual voice coil sub speaker. Here's the one I'm referring to:

Rockford Fosgate T110D2 Power Stage 1 10" subwoofer with dual 2-ohm voice coils at Crutchfield Signature

My "issue" is that it has a total peak of 1200 watts, but it's rated at 300 watts per voice coil. To me, that means I don't want to punch anything over 300 watts into this speaker, since each coil is only rated to 300 watts.

The bottom line is that 300 watts will be plenty sufficient in my Jeep JK as I'm only going to be pushing this single 10-in sub. So, a mono 250w at 4 ohm amp should be plenty of power to push this "little" guy. It's the "300 watts per coil" that's getting me, since it seems *that's* my RMS area, NOT the 1200 watt peak which is both coil's COMBINED peak.

Thoughts?
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Laminar
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Aug 16, 2010, 08:05 PM
 
The general rule, from what I understand, is that you want more amp than combined RMS wattage. I've never seen a good explanation for why this is but it's what everyone seems to believe.

Since your sub is 300W RMS per coil, you have 600W RMS combined. You'll want an amp pushing at least that to properly power the sub.

But you're right in ignoring max watts, that's just used for advertising.
     
RAILhead  (op)
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Aug 16, 2010, 09:25 PM
 
I got in touch with Rockford Fosgate, and they said to consider the dual 300w coils as a single 600 watt speaker, so 600 is the area I'm looking for.
"Everything's so clear to me now: I'm the keeper of the cheese and you're the lemon merchant. Get it? And he knows it.
That's why he's gonna kill us. So we got to beat it. Yeah. Before he let's loose the marmosets on us."
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tooki
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Aug 17, 2010, 03:03 PM
 
Also, one reason for getting an amp more powerful than the speakers is the same as why you want speakers that go louder than you need: running the device at full-blast means lower sound quality, more noise (i.e. hiss and whatnot). It’s better to have a more powerful device running comfortably within the middle range of what it can do.
     
Thorzdad
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Aug 17, 2010, 06:03 PM
 
What you want, in this application, is an amp that delivers a minimum of 600w rms (that's continuous power, not peak) per channel. Car amp manufacturers can be pretty shoddy with their specifications and call an amp that only delivers 300w peak per channel a 600W amp. I'd opt for an amp that pushes at least 800w rms per channel. Such an amp should have no problems handling the peak transients for those speakers.
     
flmiller
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Aug 17, 2010, 10:40 PM
 
And to think that Radio City Music Hall in NY used a 60 watt (yes 60w - I saw it) vacuum tube amplifier for many years. My, how times have changed!
     
Laminar
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Aug 17, 2010, 11:01 PM
 
This is the cheapest amp I could find on Crutchfield that puts out 800W RMS x 1 at 4 ohm. You'd be better off getting the 4ohm dual voice coil sub and wiring it for a 2 ohm load, as amps putting out 700-800 W RMS at 2 ohm will run you about $100 less.
     
Doofy
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Aug 22, 2010, 10:17 AM
 
Originally Posted by Laminar View Post
The general rule, from what I understand, is that you want more amp than combined RMS wattage. I've never seen a good explanation for why this is but it's what everyone seems to believe.
IIRC, the reason for this is that tweeters don't like receiving a distorted signal - tends to fry them faster. Thus, a larger amp on a lower gain setting gives less distortion than a smaller amp on a higher gain setting.

AFAIK this doesn't apply to woofers, since woofers generally cope with distortion pretty well.
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