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bubslewis
02-24-2006, 09:16 PM
In my home theater system I have a frontal array of two 8 ohm self powered speakers and a pair of 4 ohm speakers with the speaker wires running thru 4 ohm resistors (receiver only had options for 6 or 8 ohm setting and I'm afraid to run them straight to 4 ohm speakers).

I have side and back satellites and a powered subwoofer. The subwoofer has speaker wire terminals and a plug input. You have option of running speaker wires to front left/right terminals on the receiver or using the plug to the sub input jack on the receiver.

Right now I'm using the plug option for the subwoofer. The length of the plug wire is only about 12 feet, so I'm forced to have the sub in close proximity to the front speakers. I'd like to put the sub in the back of the room (26" x 17') where I think it would do more good.

Questions: Do they even make plug wires that run 35 to 40 feet in length and is it advisable to even use something like that for that kind of distance.?

Is it safe to run speaker wire from the sub to the front left/right speaker inputs of the receiver that are already running the 4 ohm speakers with the resistors? I don't think a powered subwoofer would add much strain by doing this but I'm sure.

Bill

N. Abstentia
02-24-2006, 09:31 PM
You'll want to use the RCA LFE output of your reciever to connect your sub. If you use the speaker wires, you won't be getting the dedicated LFE channel when watching 5.1 movies....in other words your subwoofer will be getting the same exact signal as your other speakers and that won't sound good. The LFE output is the only way to do it right. 40 feet is long, but not too long. You should be able to find 35 or 50 foot subwoofer cables no problem.

I'd also yank those resistors from your other speakers (or remove the speakers entirely as they are not needed and do more harm than good). Using those resistors is just asking for trouble...such as a shorted/burned resistor which could fry your amp or worse case burn a hole in your carpet when the molten mass falls of burned resistor falls to the floor. Hopefully it won't burn your house down!

Using an external resistor is such a bad idea on so many levels...the least of which is you're now totally screwing up your internal crossovers...get rid of them right now.

Eric Z
02-25-2006, 08:45 AM
Why do you think the sub would be better in the back of the room compared to the front? Usually, you find the subwoofer in the front of the room either in the corner to the left or right of the front speakers. I haven't heard any benefits of having the sub in the back of the room. If there's not much difference, you wouldn't even have to worry about running a 30'+ cable.

Smokey
02-25-2006, 08:07 PM
Using an external resistor is such a bad idea on so many levels...the least of which is you're now totally screwing up your internal crossovers...get rid of them right now.

I agree. Using 4 ohm resistors in series with 4 ohm speakers will also waste power (which speakers need) from the amp and turn it into heat.

bubslewis
02-27-2006, 03:31 PM
Why do you think the sub would be better in the back of the room compared to the front? Usually, you find the subwoofer in the front of the room either in the corner to the left or right of the front speakers. I haven't heard any benefits of having the sub in the back of the room. If there's not much difference, you wouldn't even have to worry about running a 30'+ cable.


Thanks for all the input. Most of my current prediciment is my own fault in that I expected way too much out of matching small sattelite speakers with big front speakers when listening to music.

I enjoyed the room filling sound of my "old" set up with 6 full range speakers using 2 in the front, 2 on the side, and 2 in the back. I either listened to 2 channel music or used the synthetic 4 channel modes on the old quad receiver. Also, I don't sit a whole lot when listening to music. I enjoyed the full room sound from any location in the room no matter where I'm located or what I'm doing.

So with my "new" set up, movies and sound are excellent. But I'm mostly sitting in the sweet spot area when watching movies and not moving around much. With music only, the sound goes from full rich in the front of the room to thin and a bit scratchy when I'm all the way in the back. Hence my reasoning for wanting to put the subwoofer in the back. Even though it's sound is nondirectional, it might aid in balancing the room sound a bit.

I really enjoy the wide sound stage the front array of speakers gives me. However, it looks like using resistors with the 4 ohm speakers is not particularly wise. So my options are:
1) Get rid of the 4 ohm speakers.
2) Take the resistors off and increase risk to receiver
3) Leave resistors on and risk burning the house down (plus cut amp power in half).
4) Any other options?

I don't listen to music/movies at ear shattering levels, but I will go to "fairly loud" occasionally. With no resistors, how much risk to receiver (135 W per channel) will there be using the occasional "fairly loud" mode?

I apologize for lack of knowledge. I've been out of the loop for many years and am just now getting back into it.

thanks,
Bill

bubslewis
02-27-2006, 04:52 PM
You'll want to use the RCA LFE output of your reciever to connect your sub. If you use the speaker wires, you won't be getting the dedicated LFE channel when watching 5.1 movies....in other words your subwoofer will be getting the same exact signal as your other speakers and that won't sound good. The LFE output is the only way to do it right. 40 feet is long, but not too long. You should be able to find 35 or 50 foot subwoofer cables no problem.

I'd also yank those resistors from your other speakers (or remove the speakers entirely as they are not needed and do more harm than good). Using those resistors is just asking for trouble...such as a shorted/burned resistor which could fry your amp or worse case burn a hole in your carpet when the molten mass falls of burned resistor falls to the floor. Hopefully it won't burn your house down!

Using an external resistor is such a bad idea on so many levels...the least of which is you're now totally screwing up your internal crossovers...get rid of them right now.


PS. Forgot to mention your work-in-progress home theater project. Only thing I have to say is"WOW".

Bill

N. Abstentia
02-27-2006, 08:19 PM
Thanks Bill!

Your best option is to throw those resistors away. I seriously doubt that you'll damage your receiver, especially if you're running them crossed over with a sub. The thing you have to realize is that even with an 8 ohm speaker the impedance varies and can measure anywhere from around 2 ohms up to 16 or 20 ohms so running 4 ohm speakers shoudn't be a problem. If it is, your amp will politely let you know by shutting itself off, preventing any damage.

And I emphasize this...if you have them crossed over (not producing any low freqencies) I'll bet you have nothing at all to worry about. Impedance varies more at low frequencies, and your amp has to work harder to drive them. So if you are not even reproducing those frequencies..no problem.