Amp and Subwoofer Wiring?

[drifter_for_life06]

Hey guys

My friend is having some trouble with his system and how to wire it.

(Before i go on, please dont post and say the brands suck, I just want feedback on any way to help come up with a resolution)

The subwoofer is an Audiobahn aw1206t dvc(dual voice coil) and the amp is a Power Acoustik ts-1920.

He had a custom box made at Tweeter and they ran the wires parallel. According to my friend and Power Acoustik the amp is not stable at 2ohms bridged. Is this going to cause a problem? We believe the answer is a definate YES?

If so, how would you guys suggest to wire it? Is it able to be wired or does the sub need to be "rewired" so it isnt running parallel?

Any feedback is highly appreciated

Ryandrifter_for_life06

[Rex]

I would think you should be able to open the box (remove sub) and re-wire as parallel.

There were a couple write ups about this, let me see if I can find them

[Rex]

Okay, I searched the archives and found this link and this post

zerothread?id=56524

Here's a little background on Series & Parallel:

* Series - A configuration in which a single current path is arranged among all components. Connecting the positive speaker output of an amplifier channel to the positive terminal of speaker # 1 , connecting the negative terminal of # 1 to the positive terminal of speaker # 2, and the negative terminal of # 2 to the negative output of the same amplifier channel is a series connection.

* Parallel - A configuration in which the same voltage is applied to all components, with current divided among the components according to their respective resistances or impedances. Example: All positive leads of two or more speakers connected together and all negative leads connected together.

* "Pro's & Con's" ... hmm that's hard to say. The main purpose is to adjust the "load" the amplifier sees. Most car audio amplifiers are designed to operate between 4 and 2 ohms. Some "high performance" amps are designed to run at 1 or even 0.5 an ohm. By using series, parallel or a combination of both you can create the ideal "load" for the amp to see/perform.

I know that's a quick overview, but it should help get things started.

<anymore questions, just ask. We'll help>

[Rex]

A trick that professional installers use to get more power out of amplifiers is to wire up speakers in different ways, playing with resistances to achieve a desired total impedance "seen" by the amplifier. Even though speakers are active loads (resistance changes with frequency), it is accepted to treat speakers as resistors with a fixed resistance value (usually 4 ohms).

By combining speakers in different ways, maximum amplifier output can be obtained. For example if a 2-channel amplifier is rated to deliver a maximum output of 400 watts at 2 ohms mono (bridged), then by hooking up two 4 ohm subwoofers in parallel, a total load of 2 ohms is "seen" by the amplifier, obtaining optimum power.

Parallel Resistance

Parallel Wiring Diagram

People commonly hook up two or more speakers to the same channel out of an amplifier in parallel. This is achieved by hooking up the negative wire from the amp to all the negative connections of the speakers, and the positive to all the positive connections of the speakers. By doing this, the load seen by the amplifier is lower. For example, if two 4-ohm speakers are wired-up in parallel, then their total resistance will be half, or 2 ohms. If three speakers are wired up in parallel, and they all have the same resistance value, then the total load would be a third of the value of each speaker's resistance. Here's a formula to calculate parallel total resistance for two speakers:

Parallel Resistance Formula 1

For more than two speakers, use the following formula:

Parallel Resistance Formula 2

So what are the advantages and disadvantages of this scheme? First, if one of the speakers burns out, then the other one(s) keep playing. If the amplifier is not designed to receive lower loads provided by hooking the speakers up in this fashion, you might end up destroying your amplifier. Check your manual or consult an expert.

Series Resistance

Series Wiring Diagram

Speakers are hooked up in series to decrease total load to an amplifier. To hook up speakers in series, connect the positive terminal of the amplifier to positive of one speaker, then hook up negative of that speaker to positive of next speaker, and so on. Then hook up negative of last speaker to negative of the amp. It is a lot easier to calculate total resistance for speakers hooked up in series. This is easily done by adding up all the individual resistances:

Series Resistance Formula

The disadvantage of hooking up speakers in series other than getting less power out of an amplifier, is that if one of the speakers burns up, the other one(s) stop working.

I'll work on adding in the diagrams.

[Silvia2b]

This might help too.zerothread?id=150105

[PoorManQ45]

Audiobahn sucks, get rid of it

Ok...

Seriously though, this is a simple problem to fix.

The sub you mentioned has a claimed 1100w RMS rating, but I personally would not even think about feeding it that much.

Wire the two voice coils in series,(utilizing the existing speaker terminal cup thingy for connections out of the box), then hook it up in mono to the amp. The amp will see a 4ohm load.

This will give you "880W x 1 RMS Bridged @ 4 Ohms"

[Silvia2b]

Does it have a speaker terminal cup? Not every one who builds boxes installs them. I usually querry the customer if they would like one, I also explain the reasons for not installing one. His box might just have a single wire coming out of it.

[PoorManQ45]

Mkay, that's fine.

Just connect the wires from the VCs to the respective positive and negative wire via a method of your choosing(I'd go with spade connectors for easy removal

[drifter_for_life06]

This is drifter friend

yes my box has the cup

I understand what you're saying about running in series but I have a ONE 4 ohm dual voice coil sub, i thought running this in series would make an impedance of 8 ohms not 4 ohms? If it is 4 ohms, my problems should be over because I don't want to push near the 1100 "RATED" rms, because I agree that is probably overrated. I may be wrong but this is what I was worrying about. Thanks.

[PoorManQ45]

so wait, it's not a DVC sub? If that's right then read no further

If it is DVC then here's an explaination. When you wire a multi-channel amp in mono mode each channel sees only a part of the total ohms. If it's a 2 channel(like this situation), then each channel sees half, or 4 ohms. If it was a four channel then each channel would see 1/4, or two ohms.

[drifter_for_life06]

thanks for all the help , i really appreciate it, i didnt know the impedance would be cut into two so making a 4 ohm load - pushing 880 watts. That should be plenty for that sub

thank you

[PoorManQ45]

You're welcome

[audtatious]

If it was a four channel then each channel would see 1/4, or two ohms.

Do what? I have never seen a 4 channel amp that would allow you to bridge all four channels into one.

In this scenario, he will be running a 8ohm load to the amp. The amp is rated at a certain wattage @ 4ohm bridged. He will be getting 1/2 that power running the sub in series.

Example: 100wpc amp (2 x 100) = 400wpc bridged (assuming a 2:1 increase for bridging in this example). 4ohm sub would pull 400w off bridged output (each channel is running at 2ohm)8ohm sub would pull 200w off bridged output (each channel is running at 4ohm)

In the above, bridging will offer no more power than running each channel to a seperate VC. Use of the 8ohm load = -3db in output.

[PoorManQ45]

Do what? I have never seen a 4 channel amp that would allow you to bridge all four channels into one.

I've seen a few before, but can't recall the brands. I was just giving an example BTW

In this scenario, he will be running a 8ohm load to the amp. The amp is rated at a certain wattage @ 4ohm bridged. He will be getting 1/2 that power running the sub in series.

Thanks, I was actually thinking about my mistake the other day, but I never got around to correcting it.

Each channel of the amp will indeed see a 4 ohm load, but the problem is that the power rating that I quoted was for each channel seeing a 2 ohm load

[audtatious]

Yeppers. Solution is to add another sub and run a series/parallel config for a +6db increase (double watts + double cone surface area > 1 sub setup), replace the sub with one that will work right, or replace the amp.

[drifter_for_life06]

Well.. since I can't add a sub to my set-up because I already have a box specifically made for this.. I guess what's the optimum thing to do here, while getting the most watts ? Is it running each channel to a voicecoil? I thought that series running at 8 ohms sounded funny without it being series/parallel ( dual sub set-up ). Thanks for the help, I still think if I got 370 watts x 2 at 4 ohms or 440 watts x 2 at 2 ohms out of it that would be enough to feed this sub since it's a little bit overrated. Or should I just attempt to sell this and buy a hifonics monoblock? Thanks but my real answer to the question is what would you do about using this amp? Thanks.

[audtatious]

The amp is rated 370x2 @4ohm or 880x1 bridged @4ohm. Running each channel to a VC would net you 740w to the sub. You are only losing 140w which is around -.6db

[EW]

Do what? I have never seen a 4 channel amp that would allow you to bridge all four channels into one.

I have never seen one either.

[Dj Dingo Murphy]

bridge 4 channels to 2. Wire one set of bridged channels to one coil, and the other set of bridged channels to the other coil. Rock and roll

[TakedaT]

bridge 4 channels to 2. Wire one set of bridged channels to one coil, and the other set of bridged channels to the other coil. Rock and roll

Have you actually done this before? Ive read that you can and that you cant.I dont know who to believe.