Audio experts help needed please.

T5 Paul · Dec 29th, 2006, 20:30

Hi.

I have fitted a 12inch sub woofer(Blaupunkt Velocity VW280) and amp (Blaupunkt VA-2100) to my V70. It sounds ok mostly but on the demo CD that came with it the cone seems to be over extending even with the gain far from max. This doesn't seem to be noticeable on my own CDs. Maybe the bass on the demo tracks is over the top?

The inputs to the 2 channel amp is fed from the left and right rear speaker wiring.

The speaker has two coils of 2ohm each. This is the first time I have seen a speaker with two coils. I have wired both of these coils into the amp as per the diagram. One pair to the L+ & L- and one pair to R+ and R-. I have been careful to keep things in phase (including the inputs).

By wiring it this way am I getting slightly different bass signals from the left and right going to the two speaker coils and making them "fight" against each other? I always thought bass was non directional so would I have been better off feeding both channels of the amp from just one signal (either left or right)?

Pedro Fandango · Dec 30th, 2006, 01:32

twin voice coils aren't unusual but never used them myself

running each coil off a seperate channel like that is no problem at all for the amp, infact it would quite like the 2ohm per channel. But i would make sure both channels are playing the same, perhaps bridge the inputs to the amp so both are producing either left or right to make sure that both coils are doing the same thing

personaly what i would do is get a mono channel amp, run both coils off it in parallel making sure the amp is 1ohm stable

T5 Paul · Dec 30th, 2006, 22:57

Quote:

Originally Posted by Pedro Fandango

i would make sure both channels are playing the same, perhaps bridge the inputs to the amp so both are producing either left or right to make sure that both coils are doing the same thing

Thanks. I'll try that.

cbyard · Dec 30th, 2006, 23:44

It would seem to me from your description of the wiring that the overall system is simply adding the signals from both channels to give a single output from the bass speaker. This would make sense audio wise, since low bass is non directional; also it's pretty much the way that a subwoofer behind the sofa works in a domestic installation :-)

If your own CDs work OK, then probably the demo CD IS "over the top" to show off the bass performance.

If you like the results and nothing goes pop, go for it!

Watch out for hearing loss in middle age..........

Chris

TheG · Dec 31st, 2006, 01:34

I would bridge the amp you have and then wire the sub in series or parallel (depending on what load the amp can take) and that way you know that you're feeding both coils the same signal. If you feed them different signals, you *can* cook them. Its not likely, but it is possible, depending on what you play.

Mar 21st, 2007, 17:56

also check if your amp has the ability to run a mono signal to the ouput stage even if you have not wired it as mono..

if it has no switches or settings to do this, then as suggested by other members run the amp bridged (also check can the amp do this) and then wire the coils in series or parallel to get the required load..

Dec 29th, 2006, 20:30	#1
T5 Paul Junior Member Last Online: Dec 14th, 2007 22:56 Join Date: Oct 2004 Location: Coventry	Audio experts help needed please. Hi. I have fitted a 12inch sub woofer(Blaupunkt Velocity VW280) and amp (Blaupunkt VA-2100) to my V70. It sounds ok mostly but on the demo CD that came with it the cone seems to be over extending even with the gain far from max. This doesn't seem to be noticeable on my own CDs. Maybe the bass on the demo tracks is over the top? The inputs to the 2 channel amp is fed from the left and right rear speaker wiring. The speaker has two coils of 2ohm each. This is the first time I have seen a speaker with two coils. I have wired both of these coils into the amp as per the diagram. One pair to the L+ & L- and one pair to R+ and R-. I have been careful to keep things in phase (including the inputs). By wiring it this way am I getting slightly different bass signals from the left and right going to the two speaker coils and making them "fight" against each other? I always thought bass was non directional so would I have been better off feeding both channels of the amp from just one signal (either left or right)?

Dec 30th, 2006, 01:32	#2
Pedro Fandango I've Been Banned Last Online: Apr 2nd, 2015 16:12 Join Date: Dec 2002 Location: can't remember	twin voice coils aren't unusual but never used them myself running each coil off a seperate channel like that is no problem at all for the amp, infact it would quite like the 2ohm per channel. But i would make sure both channels are playing the same, perhaps bridge the inputs to the amp so both are producing either left or right to make sure that both coils are doing the same thing personaly what i would do is get a mono channel amp, run both coils off it in parallel making sure the amp is 1ohm stable

Dec 30th, 2006, 23:44	#4
cbyard TDC Member ;-) Last Online: Jun 13th, 2020 19:08 Join Date: Jan 1970 Location: Witney	It would seem to me from your description of the wiring that the overall system is simply adding the signals from both channels to give a single output from the bass speaker. This would make sense audio wise, since low bass is non directional; also it's pretty much the way that a subwoofer behind the sofa works in a domestic installation :-) If your own CDs work OK, then probably the demo CD IS "over the top" to show off the bass performance. If you like the results and nothing goes pop, go for it! Watch out for hearing loss in middle age.......... Chris

Dec 31st, 2006, 01:34	#5
TheG growl, woosh! Last Online: Feb 5th, 2018 15:46 Join Date: Oct 2006 Location: London View Photos By: TheG	I would bridge the amp you have and then wire the sub in series or parallel (depending on what load the amp can take) and that way you know that you're feeding both coils the same signal. If you feed them different signals, you can cook them. Its not likely, but it is possible, depending on what you play.

Mar 21st, 2007, 17:56	#6
MethodMan Guest Location:	also check if your amp has the ability to run a mono signal to the ouput stage even if you have not wired it as mono.. if it has no switches or settings to do this, then as suggested by other members run the amp bridged (also check can the amp do this) and then wire the coils in series or parallel to get the required load..

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)