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Originally posted by ThomasW
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That's what I thought. But I have been told that the dual 2 ohm RL-p15 models a little better than the dual 4 ohm. So which driver is considered the best fit for the EP1500, the dual 2 ohm with voice coils powered seperately to each channel or the dual 4 ohm with same setup. Obviously the EP1500 puts out much more power at 2 ohms but if it can't keep up then that doesn't matter. Here is what I get in Win-isd. Is that much of a difference in the "real world"? -
The VC's of the dual 2 ohm driver should be wired in series to create a single 4 ohm load. Strap the amp into mono and hold on ....:wink:
IB subwoofer FAQ page
"Complicated equipment and light reflectors and various other items of hardware are enough, to my mind, to prevent the birdie from coming out." ...... Henri Cartier-Bresson -
I was under the impression that a 4 ohm bridged-mono load stresses the amp the same as a stereo 2 ohm load. But I am no expert at this stuff--actually, I may not even be to the "novice" level yet. :BOriginally posted by ThomasWComment
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Lots of people are running these amps strapped it's no big deal since it will barely be off idle powering a ported sub.
You can certainly buy the dual 4 ohm unit and run one VC to each channel.
The computer models will look a bit different; but in the real world, any performance difference between the 2-2 ohm and the 2-4 ohm drivers will be minimal.
IB subwoofer FAQ page
"Complicated equipment and light reflectors and various other items of hardware are enough, to my mind, to prevent the birdie from coming out." ...... Henri Cartier-BressonComment
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Thanks ThomasW! I really appreciate the quick help.
BrettComment
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My understanding is the same as yours, so which version of the speaker is best for your situation really boils down to whether or not the amplifier is single channel or stereo, whether or not it can drive a 2 ohm load and how much power the amp can put out relative to what the speaker can handle. If the amp can handle the load, you can dump more power into the speakers with the 2 ohm VC version. But this may not be important if you've already got more power than the speakers can handle or than you need. But Thomas is right, if the 4 ohm load meets your power requirements it will be a better choice as it allows the amplifier to run cooler and last longer.Originally posted by palmtree
For example, if the amp can deliver 2 x 400 watts into 4 ohms and 2 x 700 into 2 ohms or 1400 watts bridged into 4 ohms, the most you can get into the dual 4 ohm speaker would be 800 watts, where as with the dual 2 ohm speaker you could get 1400 watts. This is assuming that the amp is not rated for bridged into 2 ohms.
I should end this by stating that this is my understanding of how all this works and there is always room for error.
Brian WalterComment
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So your saying its better to bridge the EP1500 and wire the D2 in series than wire each channel to each VC? Why would it be better? Will you realy hear a difference doing it the bridge way? How would I know if the amp could not handle the 2 ohm load? Wont the amp blow the built in fuse and shut off or does it do something else if it cant handle it? I cant say I have ever had a problem running a 2ohm load unless its doing something Im not noticing.Originally posted by ThomasWComment
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That's all true but it's not quite that simple. Speakers aren't simple resistive loads. Here's the impedance curve of a nominal 8-ohm sub and, as you can see, the impedance varies between 6 and 46 ohms. Modelling it as a simple 8-ohm load will give you incorrect information about amp capabilities and requirements. Software is your friend.For example, if the amp can deliver 2 x 400 watts into 4 ohms and 2 x 700 into 2 ohms or 1400 watts bridged into 4 ohms, the most you can get into the dual 4 ohm speaker would be 800 watts, where as with the dual 2 ohm speaker you could get 1400 watts.
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You are correct that it is not quite that simple, but I would expect the relationship between the two drivers to be similar to that of my example. Assuming the curve you have shown is for the RL-p15 dual 4 ohm voice coil, it would be interesting to see the curve of the dual 2 ohm voice coil driver plotted on the same graph. I suspect you would see the dual 2 ohm curve about 1/2 of the dual 4 ohm curve. If so, my assumption of close to double the power would be pretty close through out the frequency response.
Brian WalterComment
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OK--so now you guys have me worried again. I already told Mike at Sound Splinter that I want the D2 but I bet I could still changed the order if necessary.Comment
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Get the D2, wire in series as Thomas suggests and enjoy. You'll be fine.Comment
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It sounds like your amp can handle the 2 ohm load, so I agree with Thomas and Kyle, go with the dual 2 ohm driver and wire the voice coils in series and drive it with the amp in bridge mode.
How long does it take to get one of the D2's? I've been seriously thinking of getting one myself.
Brian WalterComment
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Mike at SS sent me any email this morning that said it was in stock and would ship within 24 hours of payment. So get em while you can.Originally posted by Brian WalterComment
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Quote:
Originally Posted by ThomasW
The VC's of the dual 2 ohm driver should be wired in series to create a single 4 ohm load. Strap the amp into mono and hold on ....
So your saying its better to bridge the EP1500 and wire the D2 in series than wire each channel to each VC? Why would it be better? Will you realy hear a difference doing it the bridge way? How would I know if the amp could not handle the 2 ohm load? Wont the amp blow the built in fuse and shut off or does it do something else if it cant handle it? I cant say I have ever had a problem running a 2ohm load unless its doing something Im not noticing.Comment
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No, not quite. I think what we were really saying is that you would be better off with the dual 2 ohm VC version compared to the dual 4 ohm. But driving the channels separately vs bridge mode makes no difference. As mentioned previously, the load the amp sees when driving a 4 ohm speaker in bridge mode is the same as driving two separate 2 ohm loads. This may not be 100% true, but from a practical standpoint it is.Originally posted by Jerm357
Brian WalterComment
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I think there are several people running the D2 with an EP1500. I haven't seen any bad reports. I wouldn't worry about it.
I personnaly run two D2s on an EP2500. Both drivers are wired in series and hooked up to seperate channels. So, I guess this is actually less power to each driver than an EP1500 in mono would be to a single. And, I've haven't had a problem.Comment
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Ive also have been running my D2 with an ep1500 in 2 ohm mode with no problem at all (I only run it at 50% gain on both channel tho). But how would one tell *if* there was a problem running a 2ohm load would the amp just shut off?Comment
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So if I understand your setup correctly--you are running your amp in 4 Ohm stereo mode. I think that 4 Ohm stereo is how these amps were made to run. But they certainly should be able to handle a 2 Ohm load in my opinion because they sure like to scream about the power output at 2 ohms. If you ask me 2 Ohm ratings shouldn't even be mentioned by the manufacturers if the amp can't handle it. It's kinda like false advertising.Originally posted by ---k---Comment
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The QSCs and their Behringer clones have extensive protection circuits. The amp won't blow up or blow a fuse or anything nasty like that. It will simply shut down for a while if it gets too hot or draws too much current or whatever. Highly unlikely to ever happen in a home environment; these things are meant to power rock concerts.Comment
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About the "false adverstising" QSC makes it quite clear in their manuals that the amps can't run at full power at 2 ohms for extended periods of time without tripping the thermal protection circuits. But that's no big; as they show in the specs, an amp running at 1/8th continuous power on music material will be clipping occasionally and there's no reason we would want to push an amp any harder than that. Who wants to listen to clipped music?Comment
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That's cool. I'm sure it will be plenty tough for my humble HT.Comment
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I thought that's what mp3's were. :rofl:Who wants to listen to clipped music?Comment
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