Sub + Amp wiring question
Quick question on how to wire a new sub into an existing amp.... Amp exists in the boat and is good to go, there just isn't a sub.
Current amp is stable @ 2 ohms, and provides 420w @ 2 ohms. I have an old sub laying around in my garage - Alpine Type-R -DVC @ 2 ohms. What would be the best way to wire this sub in? Connect one voice coil @ 2 ohms? Connect the DVC coils in series @ 4 ohms? Connect DVC oils in parallel @ 1 ohm?... and hope the amp doesn't go haywire |
Just wire one of the VC's, I've done this before with no issues. The handling power of the sub is dropped but you should be fine with just 400 watts, worst case scenario you'll have a little head room and hey if you blow that VC you have another one left! You're a lot less likely to have issues with this set up than trying to run the amp at 1ohm.
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i agree, most amps and or speakers won't last long at 1 ohm..
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You cannot run on one coil of a DVC
No issue running your 2 ohm DVC sub in series @ 4 ohm. Just wont be tapping into the available 420W No, dont run the sub parallel @ 1 ohm, the amp wont like it. |
I guess there is one other option, since I have two of these Type-Rs from our old boat.....I didn't want to run two subs to eat that much of my storage space up, but I could go:
Sub 1 DVC parallel @ 1 ohm --> Series to --> Sub 2 DVC parallel @ 1 ohm = Total load would be 2 ohms between the two subs. I plan on giving the whole setup a clean sweep this winter, new amps, sub, tower speaker, etc etc etc.... but to get my by this summer and using the stock amp/speakers was looking for the best way to run what my garage had laying around. |
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You can run the voice coils in series, parallel or with one voice coil per identical channels. In this particular case, connect the VCs in series. |
Honestly, there is no harm only running one coil wired on a DVC. The only negative affect will be power handling loss from 1/2 to 2/3 less. Which equates to less output :(.. A resistor on the other coil will change the Q also ;) many professional installers have done this with no returns. Would I do this? NO, but many friends in the 12volt community have...
But I agree you should run it at 4ohms with both coils on the sub being used. |
I have it in series now, looks like it will stay that way.
Thanks for the input! |
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I have not performed it, but my assumption would be a 4 ohm resister in parallel with the 4 ohm speaker load ( 2 2-ohm speakers in series) or a 1 ohm resister in series with the 1 ohm speaker load ( 2 2-ohm speakers in parallel)...
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A lot of amps are stable at 2 ohm, but not 2 ohm mono. 2 ohm ratings most of the time are 2 ohm stereo.
It would help if you'd just put what amp you have instead of us making assumptions. Michael Gunnett, I've got a boat in my shop right now with an older Wet Sounds Syn1 and 12" XXX sub. This setup is 4 years old. The amp is wired down to 1 ohm, and the amp has been powering it for the entire 4 years. Its back in teh shop for a new enclosure. |
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I am assuming full/high pass channels 1/2 are controlling the tower speakers ... and the sub channel is where the Type R is attached to. |
Are you sure its a sony? Thats kicker model also. And if it is the Kicker KX550.3, the sub chnl 3 is not 1 ohm stable.
I know some NASCAR guys and they run their engine with only the odd numbered plug wires connected on the even days of the week and the engines dont come back, or make it back, not sure which. |
Yes, Its kicker, my bad!... all the speakers are sony.
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No way I know something David doesn't.... Somehow I feel a rebutted explanation coming on why everyone else is wrong in doing this... :) |
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Proper equipment first. I love that statement! More people need to practice this!
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Ah yes, essentially a two ohm resistor across each 2 ohm voice coil (i.e., in series) to get two 4 ohm loads (each voice coil) to run in parallel at 2 ohms.
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Strike that, the connecting the resistor between the posts would represent a parallel load, not a series load so the 2 ohm resistor would yield a 1 ohm load per voice coil and then a series load of 2 ohms.
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As an Acoustic Enginner in the early 90's I tried developing a variable-Q subwoofer that utilized a variable power resistor across an "unused" voice coil. The idea is that the coil moving in and out in the woofer's motor creates an AC signal much like an amplifier Ther is voltage potential, but no current. The external resistor becomes the "load" for the voice coil.. When the resistor is connected though a funny thing happens... Current flows through the resistor and also the coil... Current through a coil makes its own magnetic field in the second coil and acts to damp the woofers motion. With an open circuit, there is no damping.
You can see the effect clearly for yourself. Take a woofer with nothing connected to the speaker leads and "exercise" the cone, pushing it in and out quickly. Now, go and get a piece of wire and short the speaker terminals and "exercise" it by pushing on it. See how much harder it is to push in and out? Now, (this is kinda awkward to do, so don't drop the woofer...) with the woofer sitting on a firm surface, push on the cone rapidly with one end of a short piece of wire connected to one voice coil. Touch and release the wire to the other voice coil. Hear the popping? That is the result of the electromagnetic field you area making... That is the how, for why it works... You CAN change the Q of a DVC woofer by appling a load to one unused coil. It works and it is easily measured. There is a problem though.... For this to properly work, (and it doesn't really work that well anyway) the woofer has to have virtually ZERO restorative force built into the spider and surround. Such a woofer will be totally floppy at rest, (part of the mechanical problem) so much so that the cone hangs out when tilted down, and falls into the enclosrue when tilted up. In the above example with the Alpine Type R, the production woofer has a suspension that assumes both coils will be driven so there is a fair amount of mechanical damping built in. When you add more damping by shorting a coil you are really just making the woofer stiffer with less efficiency. You are adding electrical Q to an already substantial mechanical Q. All you get is more damping, with a woofer that requires a larger box, all at lower power handling and lower efficiency. It is like this: :banghead: The other key problem is this. Consider the amplifier is providing power by applying a voltage to the wired coil, with a known impedance that causes current to flow, thereby creating power., (Power=Current x Voltage) When you put a load resistor on a second coil, you are doign the same thing, creating voltage and current in the second coil. the voltage changes, with voltage being greater with more woofer movement. Mathematically it becomes apparent that the damping force changes relative to amplifier output. Amp off; no movement, no induced voltage and current in secondary coil, no damping. Amp on and playing quiet, woofer moves a little, a little bit of damping in second coil. Turn the amp way up. Big woofer movement, big amplitude and current in second coil, even more damping. Put another way, the more you turn it up, the more you try to turn it down....... 'Been there, done it, built a woofer to take advantage of it. While it works, it really doesn't. Trust me.... Phil Kicker |
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Awesome info!!!! Thank you for that reply! Looks like its just going to be a matter of me starting from scratch and building a system of components that were meant to be together rather than try to salvage the existing setup. .... Kicker isn't looking for a project boat that will be seen by almost no-one in central Wisconsin, are they? ...... Didn't think so. |
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"...everyone else..." sounds like a majority or something that is commonplace. I don't see where that is the case. JL Audio clearly states that a) you have to be able to measure the altered T/S parameters, and b) they don't recommend it. In JL Audio, Vance Dickason, and Phil I trust. Either you 'know' it because you read it on an internet forum or you really 'know' how to administrate it. I'm was simply asking how you actually put it to task. |
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1) Using only one voice coil will give you a 3 dB loss and change the speaker parameters. 2) Using both voice coils in series and getting less than the maximum amplifier power will still yield more output than the loss associated with using only one of two coils. Typically when you double the impedance you do not halve the amplifier power. But you do end up with some nice tight sound and a little headroom. I don't see much compromise in this. Just try it. |
^^^^What David Said^^^^^
Phil Kicker |
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Thanks Phil for writing it out for David... |
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