will this cause problems?

slackerbob · 26th November 2003, 01:49 AM

Well, i have 2 4 ohm drivers in my center channel. right now, they're hooked up in parallel for a total of 2 ohms. also, i've got another driver of unknown impedence also in parallel with an inductor on it to help out with the bass. Is this net impedence of less than 2 bad for my amp? Will it cause problems? btw, the amp's supposed to have 8 ohm speakers connected to it.

thanks

Brett · 26th November 2003, 07:04 AM

It will depend on the amp. Most, except Pro PA amps, will HATE such a low load, and probably be putting out less than rated power.

wintermute · 26th November 2003, 07:05 AM

Probably

Especially if the amp is rated for 8 ohm loads! Why don't you wire the mid-bass drivers in series, shouldn't make much difference to efficiency and you amp will be much happier!

Regards,

Tony.

slackerbob · 29th November 2003, 02:43 AM

how about wiring a ~6k resistor in series? i really don't want to take apart the box again... screws are such a pain when you have to put them in by hand...

Brett · 29th November 2003, 03:57 AM

Quote:

Originally posted by slackerbob
how about wiring a ~6k resistor in series?

Presume you mean 6 ohm, not 6k ohm.
That will give the amp the 8 ohms it will like to see, but 75% of the amps power will now be used up just heating this resistor, ie not contributing to the sound output and will throw off the crossover.

Looking back to your first post, could you please detail exactly what the drivers are, and how they're connected? Are two of the drivers the same, or are they a woofer and a tweeter etc? Is there any other crossover apart from the inductor you mentioned in series with the 3rd driver?

sreten · 29th November 2003, 12:04 PM

The 6 ohm (presumably) resistor will lose a lot of power
and compromise the bass damping severely.
In engineering terms its a very poor solution.

2 ohms is a very poor load for your average A/V amplifier,
resistive losses in the amplifier will be serious. Power output
is likely to be a 1/4 of or less than that into 8 ohm.

As said above you should wire the units in series, its possible
you may have to increase the inductor value on the other driver
to maintain the bass balance.

/sreten.

slackerbob · 29th November 2003, 06:17 PM

hmm, lets see

there are 2 4" drivers in parallel.
in parallel with these is a bass driver and an inductor.

maybe i should add a capacitor to the 4 inchers, because they don't add a lot.

okie, i'll take my box apart and redesign everything. heh heh

thanks for the input though

sreten · 29th November 2003, 06:31 PM

Just my opinion but adding the capacitor will be more trouble
than its worth, unless your extra driver is over 6.5 inches.

I assume they are all in the same box ?

If so then just play with the inductor value for a decent balance.

/sreten.

slackerbob · 29th November 2003, 06:38 PM

so, keep the bass driver in parallel, but put the 4" drivers in series?

sreten · 29th November 2003, 07:25 PM

Yes, seems you've got it :

keep the bass driver in parallel with its inductor,
the two 4 inch 4 ohm drivers in series.

You never know, you might get a better balance than before !

Whats certain is you'll get more power from your amplifier,
and your extra bass driver will be capable of adding more
bass than in your previous arrangement.

/sreten.

26th November 2003, 01:49 AM	#1
slackerbob diyAudio Member Join Date: Jun 2003 Location: Harvey Mudd College; Claremont, CA	will this cause problems? Well, i have 2 4 ohm drivers in my center channel. right now, they're hooked up in parallel for a total of 2 ohms. also, i've got another driver of unknown impedence also in parallel with an inductor on it to help out with the bass. Is this net impedence of less than 2 bad for my amp? Will it cause problems? btw, the amp's supposed to have 8 ohm speakers connected to it. thanks

26th November 2003, 07:05 AM	#3
wintermute just another diyAudio Moderator Join Date: Aug 2003 Location: Sydney Blog Entries: 22	Probably Especially if the amp is rated for 8 ohm loads! Why don't you wire the mid-bass drivers in series, shouldn't make much difference to efficiency and you amp will be much happier! Regards, Tony. __________________ Any intelligence I may appear to have is purely artificial! Some of my photos

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26th November 2003, 07:04 AM	#2
Brett diyAudio Member Join Date: Jan 2002	It will depend on the amp. Most, except Pro PA amps, will HATE such a low load, and probably be putting out less than rated power.

29th November 2003, 02:43 AM	#4
slackerbob diyAudio Member Join Date: Jun 2003 Location: Harvey Mudd College; Claremont, CA	how about wiring a ~6k resistor in series? i really don't want to take apart the box again... screws are such a pain when you have to put them in by hand...

29th November 2003, 12:04 PM	#6
sreten diyAudio Member Join Date: Nov 2003 Location: Brighton UK	The 6 ohm (presumably) resistor will lose a lot of power and compromise the bass damping severely. In engineering terms its a very poor solution. 2 ohms is a very poor load for your average A/V amplifier, resistive losses in the amplifier will be serious. Power output is likely to be a 1/4 of or less than that into 8 ohm. As said above you should wire the units in series, its possible you may have to increase the inductor value on the other driver to maintain the bass balance. /sreten.

29th November 2003, 06:17 PM	#7
slackerbob diyAudio Member Join Date: Jun 2003 Location: Harvey Mudd College; Claremont, CA	hmm, lets see there are 2 4" drivers in parallel. in parallel with these is a bass driver and an inductor. maybe i should add a capacitor to the 4 inchers, because they don't add a lot. okie, i'll take my box apart and redesign everything. heh heh thanks for the input though

29th November 2003, 06:31 PM	#8
sreten diyAudio Member Join Date: Nov 2003 Location: Brighton UK	Just my opinion but adding the capacitor will be more trouble than its worth, unless your extra driver is over 6.5 inches. I assume they are all in the same box ? If so then just play with the inductor value for a decent balance. /sreten.

29th November 2003, 06:38 PM	#9
slackerbob diyAudio Member Join Date: Jun 2003 Location: Harvey Mudd College; Claremont, CA	so, keep the bass driver in parallel, but put the 4" drivers in series?

29th November 2003, 07:25 PM	#10
sreten diyAudio Member Join Date: Nov 2003 Location: Brighton UK	Yes, seems you've got it : keep the bass driver in parallel with its inductor, the two 4 inch 4 ohm drivers in series. You never know, you might get a better balance than before ! Whats certain is you'll get more power from your amplifier, and your extra bass driver will be capable of adding more bass than in your previous arrangement. /sreten.