Driving dual voice coil sub with two independent stereo channels

[frikk 10+ year member]

Thank you

Not to drag it out more - but what advantage does the 8 ohm load bridged have over just using a single channel?

 

[dipitydoo 10+ year member]

That question was answered several times already. Go back and re-read some of the posts. I know it might sound confusing with the varying answers, but read carefully.

 

[frikk 10+ year member]

hah alright - thanks man.

peace,

blaine

 

[Stel 10+ year member]

The amp is capable of 350w bridged at 4 ohms. If it's wired to an 8 ohm load while bridged it is only capable of roughly half of it's 4 ohm output, regardless of mono or stereo inputs. The best solution would be to find a new driver with dual 2 ohm coils, or a new amp that is a better match, ie one that can put out the power you want at 2 ohms. That is if you want to be using the full power of your amp.

Don't use separate channels to drive the voice coils. You can wreak your equipment this way. Also combining the RCA preouts from the HU with a y cable is not usually recommended, it can cause problems with the HU, directly shorting the left and right channels.

 

[frikk 10+ year member]

The amp is capable of 350w bridged at 4 ohms. If it's wired to an 8 ohm load while bridged it is only capable of roughly half of it's 4 ohm output, regardless of mono or stereo inputs. The best solution would be to find a new driver with dual 2 ohm coils, or a new amp that is a better match, ie one that can put out the power you want at 2 ohms. That is if you want to be using the full power of your amp.
Don't use separate channels to drive the voice coils. You can wreak your equipment this way. Also combining the RCA preouts from the HU with a y cable is not usually recommended, it can cause problems with the HU, directly shorting the left and right channels.

Thats everything I'd need to know. Thanks a bunch!

I'll end up using one channel most likely so I don't have to worry about the RCA cables. I could do the 8-ohm load, but I don't think it'd matter either way.

I got the sub for free - so no sense in complaining that I can't get maximum power out of the bridge //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[dipitydoo 10+ year member]

The amp is capable of 350w bridged at 4 ohms. If it's wired to an 8 ohm load while bridged it is only capable of roughly half of it's 4 ohm output, regardless of mono or stereo inputs. The best solution would be to find a new driver with dual 2 ohm coils, or a new amp that is a better match, ie one that can put out the power you want at 2 ohms. That is if you want to be using the full power of your amp.
Don't use separate channels to drive the voice coils. You can wreak your equipment this way. Also combining the RCA preouts from the HU with a y cable is not usually recommended, it can cause problems with the HU, directly shorting the left and right channels.

I see why frikk is so confused. Lots of misinformation in this post. Let me make a few corrections, some of which has already been stated.

The amp is rated at 600w at 4 ohm mono, not 350w. As stated several time earlier, 8 ohm mono power is the same as two 4 ohm stereo power combined (350w). The sub is rated at 400w, so 350w (from 8 ohm mono) is about right for that sub. 4 ohm mono power from that amp is 600w, above the power handling rating of the sub. To get full power from that amp, simply adding another same sub will be the best option.

You will not wreck your equipment by wiring in stereo. If by a slim chance you come across a recording with bass in stereo that has different material per channel, the difference in output will be added or canceled. This is much like wiring two coils out of phase, which will result in no sound output, not the sub 'tearing itself apart'.

As far as the RCA situation, we are not combining the outputs from the HU's preouts into one. Its the other way around. 1 cable to 2 cable out.

 

[dipitydoo 10+ year member]

Thats everything I'd need to know. Thanks a bunch!
I'll end up using one channel most likely so I don't have to worry about the RCA cables. I could do the 8-ohm load, but I don't think it'd matter either way.

I got the sub for free - so no sense in complaining that I can't get maximum power out of the bridge //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

Bridge amp, wire two coils in series. Connect both rca (L+R) to the amp's input. Done.

 

[frikk 10+ year member]

I see why frikk is so confused. Lots of misinformation in this post. Let me make a few corrections, some of which has already been stated.
The amp is rated at 600w at 4 ohm mono, not 350w. As stated several time earlier, 8 ohm mono power is the same as two 4 ohm stereo power combined (350w). The sub is rated at 400w, so 350w (from 8 ohm mono) is about right for that sub. 4 ohm mono power from that amp is 600w, above the power handling rating of the sub. To get full power from that amp, simply adding another same sub will be the best option.

You will not wreck your equipment by wiring in stereo. If by a slim chance you come across a recording with bass in stereo that has different material per channel, the difference in output will be added or canceled. This is much like wiring two coils out of phase, which will result in no sound output, not the sub 'tearing itself apart'.

As far as the RCA situation, we are not combining the outputs from the HU's preouts into one. Its the other way around. 1 cable to 2 cable out.

Thank you very much, I appreciate that clearup. That makes a lot of sense! Thanks again //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

Bridge amp, wire two coils in series. Connect both rca (L+R) to the amp's input. Done.

I may be beating a dead horse, but is there a disadvantage over just connecting my two voice coils to a single channel in parallel? Yeah - I won't be maximizing the utilization of my amp. Oh well, I can live with that.

Thanks everyone, this has been EXTREMELY helpful!

-blaine

 

[dipitydoo 10+ year member]

I imagine you could do that without a problem. Since amp's rarely double their power at 1/2 impedance, you will get somewhat less power than if you bridged the amp and wired the coils in series. I doubt the difference will really be noticeable, though.

 

[n2audio 5,000+ posts]

I may be beating a dead horse, but is there a disadvantage over just connecting my two voice coils to a single channel in parallel? Yeah - I won't be maximizing the utilization of my amp. Oh well, I can live with that.

Technically I guess it wouldn't make much difference, but running 1 ch all out and not using the other seems a little ghetto to me. Especially when bridging into 8 ohms would be no more hassle.

 

[Stel 10+ year member]

Sorry, thought I read that amp did 350rms @ 4ohm bridged somewhere. If it's 600rms it will be an ok match bridged to that sub wired to 8 ohms (voice coils wired in series). The sub will have around 300rms to it. Still not a perfect match but ok. The 600rms number is at 12.5 Volts DC. You might have a bit more voltage than this which will be an even closer match.

1. Running it in stereo (Left to the Voice Coil 1, Right to Voice Coil 2) is a bad idea, correct? This would probably damage my sub since the signals would be out of phase (and possibly completely different)

This can damage the sub, don't do it.

As stated above you can connect your left and right rca's to the amp and operate the amp in bridged mode and this will effectively combine the channels safely.

 

[squeak9798 5,000+ posts]

This can damage the sub, don't do it.

As dipitydo mentioned, this is a myth.

You won't damage the driver by sending different signals to the two coils.

Mr. Wiggins covered this topic in one of his tech papers;

http://www.adireaudio.com/Files/DualVoiceCoilDrivers.pdf

 

[Stel 10+ year member]

Interesting read. My concern was the potential for extra heat buildup since it would be possible, however unlikely, to send out of phase signals to each coil. I've read that a sub's motion is an important part of it's cooling. So if it wasn't moving enough and was getting near it's rated power I would guess eventually it could damage it. But true, in the real world it's unlikely there would ever be, at least for long, a signal that much out of phase to the sub with no other in phase signal to keep it moving.