long wires in chain

Trist · 7th January 2002, 01:40 PM

My speakers are rather far away from my system, about 20 feet of wire or so, this is because the wire has to go around my bed and stuff, so it is out of the way. Now, i know long cables aren't cool, so i have to make a decision.

1. Have long speaker cables going from the mono blocs to the speakers, and short wire going from the pre-amp to the mono-blocs.

2. Have long cables going from the pre-amp to the mono blocs, and short cables from the mono blocs to the speakers.

Which of these two situations is the best?

Thanks

sandro · 7th January 2002, 01:54 PM

Except strange (and rare) eceptions, solution 2 is the best.

If you know the out impedance of your pre and the input impedance of the monoblocks then we'll be sure that your case is not an 'exception'.

bye
sandro

kelticwizard · 7th January 2002, 07:05 PM

I second Sandro.

The problem with long speaker wires is that the longer the speaker cable, the greater the resistance. When sufficiently long, this resisance gets large enough to actually affect the sound of a 4 ohm or 8 ohm speaker. A quarter of an ohm can actually do this.

The interconnnect between preamp and power amplifier is a high impedance connection. 600 ohm is standard, but the input impedance of most modern units is higher. Even one or two ohms have no real effect on a connection that is 600 ohms or higher. If the 20 foot long interconnect has 2 ohms resistance-which it won't-it is the equivalent of your speaker cable having a resistance of .013 ohms running to a 4 ohm speaker, which won't affect anything.

Hence, you are better off making the long connection from preamp to power amp.

Super · 7th January 2002, 07:38 PM

I believe that depending on the gauge of your speaker wire, you could also run into capacitance problems with excessively long runs, and could cause your amplifier to oscillate. I would go for #2 definitely.

navin · 8th January 2002, 10:23 AM

use 2 for 2 reaasons.

1. speaker wire is thicker and uglier than interconnect wire. Next time when I renovate my room all my speaker will be active. this way thin interconnct wire is all I need. Hell I think the ideal way to do thsi is to use XLR and send signals to Hi and Lo pass sections along one wire.

2. speaker wire has to have an impedance less than 0.1 ohms for a 4 ohms speaker and 0.2 ohms for a 8 ohm speaker. Actually few speakers are really 8 ohms most are around 6 ohms on an average across the frequency spectrum so really you need to keep impedance of speaker wire to less than 0.15ohms. Thick wire like this will have skin effect and high capacitance (reactance). Stranded wire has other problems that I will not go into here.

Note that If you use 2, you will need a power plug near each monoblock so ensure you have that or you will have power wire which is uglier than speaker cable going everywhere.

Have fun

Regards
Navin

7th January 2002, 01:40 PM	#1
Trist diyAudio Member Join Date: Jul 2001	long wires in chain My speakers are rather far away from my system, about 20 feet of wire or so, this is because the wire has to go around my bed and stuff, so it is out of the way. Now, i know long cables aren't cool, so i have to make a decision. 1. Have long speaker cables going from the mono blocs to the speakers, and short wire going from the pre-amp to the mono-blocs. 2. Have long cables going from the pre-amp to the mono blocs, and short cables from the mono blocs to the speakers. Which of these two situations is the best? Thanks __________________ Trist

7th January 2002, 07:38 PM	#4
Super diyAudio Member Join Date: May 2001 Location: Connecticut	I believe that depending on the gauge of your speaker wire, you could also run into capacitance problems with excessively long runs, and could cause your amplifier to oscillate. I would go for #2 definitely. __________________ Bryan

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7th January 2002, 01:54 PM	#2
sandro diyAudio Member Join Date: Dec 2001 Location: Milano, Italy	Except strange (and rare) eceptions, solution 2 is the best. If you know the out impedance of your pre and the input impedance of the monoblocks then we'll be sure that your case is not an 'exception'. bye sandro

7th January 2002, 07:05 PM	#3
kelticwizard diyAudio Member Join Date: Sep 2001 Location: Connecticut, The Nutmeg State	I second Sandro. The problem with long speaker wires is that the longer the speaker cable, the greater the resistance. When sufficiently long, this resisance gets large enough to actually affect the sound of a 4 ohm or 8 ohm speaker. A quarter of an ohm can actually do this. The interconnnect between preamp and power amplifier is a high impedance connection. 600 ohm is standard, but the input impedance of most modern units is higher. Even one or two ohms have no real effect on a connection that is 600 ohms or higher. If the 20 foot long interconnect has 2 ohms resistance-which it won't-it is the equivalent of your speaker cable having a resistance of .013 ohms running to a 4 ohm speaker, which won't affect anything. Hence, you are better off making the long connection from preamp to power amp.

8th January 2002, 10:23 AM	#5
navin diyAudio Member Join Date: Jan 2002 Location: Mumbai (Bombay), India	use 2 for 2 reaasons. 1. speaker wire is thicker and uglier than interconnect wire. Next time when I renovate my room all my speaker will be active. this way thin interconnct wire is all I need. Hell I think the ideal way to do thsi is to use XLR and send signals to Hi and Lo pass sections along one wire. 2. speaker wire has to have an impedance less than 0.1 ohms for a 4 ohms speaker and 0.2 ohms for a 8 ohm speaker. Actually few speakers are really 8 ohms most are around 6 ohms on an average across the frequency spectrum so really you need to keep impedance of speaker wire to less than 0.15ohms. Thick wire like this will have skin effect and high capacitance (reactance). Stranded wire has other problems that I will not go into here. Note that If you use 2, you will need a power plug near each monoblock so ensure you have that or you will have power wire which is uglier than speaker cable going everywhere. Have fun Regards Navin