View Full Version : Stereo Expert Help

01-22-2006, 06:27 PM
I am currently running 4 Polk DB650's powered with a Sony Xplode Amp. I want to add two DB650 tower speakers and if I can, a bow speaker for 7 speakers total. My amp is rated down to 2ohms and if I understand it right 2-4ohm speakers in parallel equal 2ohms. I am planning on running the 4 cockpit speakers off of the left front and right front of the amp. Two speakers off of each channel in will be wired in parallel. I then want to run the two tower speakers in parallel off of one of the rear channels and the bow speaker off of the last rear channel. Is this workable?

01-23-2006, 09:33 AM
You generally want an equal load across channels. Your setup is viable except for the single speaker on the fourth channel. If you can find a way to get a 2 ohm load on that channel, it would be better.

Why the single speaker? If it's a sub, you can look for a dual voice coil model and wire the VC's in parallel to produce a 2 ohm load.

01-23-2006, 09:55 AM
RackAtak- Why are you running only the tower speakers on one channel, and why is there only one bow speaker? Since you probably won't be able to buy one speaker, why not find a way to mount a pair up front?

BTW, if the amplifier has discreet output devices, it's not that much of a problem to have a different load on one channel. Also, the tower speakers don't need to see a full range signal, so you might consider a high pass filter cap for them. This will not only keep deep bass from torching them but it makes the amp happier, too. Something in the range of 150mF. If you want to set the frequency yourself, the formula is C= 1/(2πFR) or, Capacitor value = 1/(2 x Pi x Frequency(crossover) x Resistance). For 150 Hz, the value will be about 265mF or as close as the standard value is to that. Get non-polarized, >24WVDC caps from a car audio installation shop.

How loud do you want it and how many people are going to be PO'd when the sound carries across the water to their location?

Make sure the power wires are adequate for running the amp at high levels with a 2 ohm load. The amp will draw a lot of current and get a lot hotter this way.

01-23-2006, 10:57 AM
I was running the tower speakers on one channel in order to get the 7th speaker in the bow. As far as the 7th speaker, I was looking for the easy way out. The only place for a speaker in the bow that I can see, without making some kind of enclosure, is the cupholder dead center in the front of the boat.

I am not looking for water rippling sound and it is definitely not my intention to p**s anyone off while on the lake. I was just looking for a way for the rider behind the boat to hear some music. :guitar: It sounds it may be easier to delete the bow speaker and stick with the four cockpit speakers and the two tower speakers...

01-23-2006, 11:19 AM
I belive that amp has built in low and high pass filters. You should be able to accomplish what JimN is suggesting without adding caps.

01-23-2006, 11:35 AM
I belive that amp has built in low and high pass filters. You should be able to accomplish what JimN is suggesting without adding caps.
The amp does have built in filters and the muddy water having to do with this stereo stuff is starting to become clear. Thanks for the input guys!

01-23-2006, 11:56 AM
The caps aren't there for actual filtering, it has to do with the DC resistance seen by the amp. The crossover filters in the amp should be used on any small speakers, though.

The bow speaker will help, but won't make a huge difference. If the space will allow a 6 1/2" speaker, another way you could go is with a stereo home theater/distributed audio speaker. Those have dual VC and two tweeters with a good crossover. You should be able to find a spare grill somewhere for a marine speaker and use that instead of the usual mount supplied.