Well, my wife just gave me the green light to go ahead and purchase another Rotel RMB1075 amp. With the new amp and the 1075 I already have, I plan to bi-amp my mains and center channel then run my side surounds and add some back sorrounds with the remaining hannels. So I am looking for some suggestions for speaker wire for the front three. The runs are through the walls (in flexible conduit) and are roughly 35 feet long. I was thinking with going with some sort of 12/4 speaker wire. Any thoughts or suggestions?

One additional question: do I just use a splitter off my 950 to split the signals into the amps? I suppose I'll need 3 splitters and 5 more RCA interconnects.

Thanks in advance,
simp

I use Canare 4S11 speaker cable and it seems great to me. Being 4 conductors you could use it for your bi-amp application.

If the wiring will be in conduit, you should have no problem picking up something simple - I'd probably go with 12ga. Something like Keta's Canare would be a good match. If you were running through attic or crawlspace areas or dropping loose in the wall, the cable should be plenum rated, which would eliminate most or all of the stuff at places like Home Depot and the Canare (according to Canare's site, none of their audio cables are plenum rated).

To passively bi-amp (no external crossover circuit), all you need is a splitter at the pre-amp output on the 950.

Gonk,
Can you go into more detail on passive bi-amping? I mean, it seems to make sense to me that I'd be in pretty good shape sending one full signal from one amp output to the high/mids and a seperate signal from a seperate amp output to the lows. I always thought that passive meant I was sending the same output from the same amp across two sets of speaker wire, one to the mids/highs and one to the lows. I must have it wrong. Maybe I misunderstood the difference between bi-wiring and bi-amping.

Thanks for the info,

simp

Your original idea (bi-amping using the extra amp channels provided by the second five-channel amp) is an example of passive bi-amping. I'm by no means the expert on bi-amping around here, but I can give you a quick overview.

Passive bi-amping: split the pre-amp output signal and feed it to two amplifiers. This option can provide some more power reserve, but the concensus from some of the forum's resident wizards is that bi-amping with a pair of 100W amps is not going to offer much if any benefit over using a single 200W amp.

Active bi-amping: take the pre-amp output and run it through a crossover circuit to create two signals - a high-passed signal for the speaker's tweater (and possibly the mid-range driver as well, depending on the speaker) and a low-passed signal for the speaker's woofer. The two signals then go to two separate amplifiers, and the output of those amplifiers goes to the speaker. To make this work, you have to get into the guts of the speaker and re-wire around the speaker's crossover network so that the speaker connections go straight from binding posts to drivers. This approach offers the most practical benefits for bi-amping, but the knowledge required to implement it (both in building a crossover that properly matches your speaker and in bypassing the speaker's original crossover) makes it impractical and unwise for most of us mere mortals.

Bi-wiring: one amp channel drives one speaker, but two speaker cables connect the amp channel to the separate sets of binding posts on the speaker. The theory here is that your high frequency drivers don't have to deal with reflected "noise" in the speaker cable from the woofer. It's fairly common (I've actually got a few speakers at home wired this way as I type this), but again the resident experts seriously question the practical value in this arrangement. It's probably just as well to use good quality jumper wires and a single speaker cable as it is to biwire - especially when you've got to run 35 feet from amp to speaker.

Excellent description. Thanks for setting me straight. I was straight on bi-amping and bi-wiring, but I was not aware of the passive vs. active bi-amping.

Getting back to the speaker wire. My only concern about the Canare 4S11 speaker wire is that it's 14 gauge, not 12.

thanks,
simp

Gonk,

A couple internet searches led me to some info on plemum rated wire. From what I've read, it is only required when wires enter an air duct (common in a commercial building). The outside coating on plenum rated wire burns at a higher temp an therefore does not send toxic gas into the HVAC system if it were to burn.

Why would plenum rated wire be required in a regular household wall? Something I'm missing? I ask becuase I'm getting ready to run some wire to my surrounds.

Your definition of plenum rated cabling is quite accurate - in commercial installations, it is required when the cabling is run exposed in a ceiling space that is used as a return air plenum (the ceiling void is used as a duct, reducing sheet metal cost and saving always-precious ceiling space). Attics and crawlspaces in homes are usually not used as plenums, but there can be cases where wall spaces are used for return air or attics serve as plenums. (There can also be cases where it wasn't intended to be a plenum but ended up that way, such as my crawlspace when we bought the house a year or so ago - previous owner had to have all the supply ductwork re-hung and sealed back up because it had fallen off the floor joists and was dumping into the crawlspace more places than it was reaching the supply registers.) I'm not sure how picky residential code is about requiring plenum-rated cable, but it's not a bad idea to use it if you can get your hands on some.

From the electricians point of view you don't need plenum rated wire in a house. Plenum rated means low smoke when a fire is burning the outer jacket letting off far fewer hazardous chemicals. The flexible conduit you have in your walls is probably plastic and isn't plenum rated. Most residential codes don't require it. Nice job having the flexible conduit in the walls by the way! Good luck Jim

Belden's description is:
Plenum — A compartment or chamber to which one or
more air ducts are connected and that forms part of
the air distribution system. A description for a cable
that passes the UL 910 CMP flame test requirements.

Look at the Belden site for tons of info.

Gonk-o-rama:

Scratching at walls in attempts to play like one of those damnable felince creatures has given me experience in wiring in walls. (It doesn't taste too good.)

Hullguy is correct, though depending on your local building codes YMMV. The NEC is almost always the basic guide, but in some jurisdictions there are "local ammendments" that say if plain-old "CL-3" wire is good for in-wall residential use, or if you need "R" or "P" rated wirings. He's also correct that the ability to NOT use "R" or "P" cable only exists with true fire-rated (read metal) conduit. If the plastic conduit isn't fire rated, then it's a nice convenience for running wires, but doesn't help with fire codes.

More than anything, what works or doesn't is based on codes, local law and at the end of the day it REALLY boils down to whether or not the inspector is in a good mood or not. After I bit the local inspector when my master and mistress were building me a new house, it resulted in a red ticket even though things were OK. Talk about being sent to the dog house!

But what do I know, I'm only a dog...

ARF ARF, says Iggy!

Sraber,
The Canare 4S11 has four 14 AWG conductors. When you use two of the conductors for the red, and the other two for the black, you have 11 gauge.

So, if you want at least 12 gauge cable, and you are going to bi-amp, you'd need to run two lengths of the 4S11 for each speaker.

Hullguy and Iggy - You guys make some excellent points. It makes sense to not need plenum-rated in a residential installation. Clearly I need to unhook the work mindset a bit more completely from time to time.

Thanks for all the replies, folks. So I've been searching far and wide for this 12/4 speaker wire and not had a whole lot of luck. I found one brand that I've never heard of before and Monster to the tune of 3+ bux a ft. So now I'm thinking I might be better off running a pair of speaker wires to each speaker. I'd like to stick with 12 gauge. Any suggestions for a nice wire at a reasonable price? I'd like to try to keep it below a buck a ft., no more than 1.50 a ft.

I see that belden 5000UE can be had for about .39/ft. But I was also intersted in this offering from Axiom Audio @ .85/ft. Any thoughts?

As always TIA,

simp

Hello sraber.. You might try googling "UL CL3" (UL rated NEC listed CL3) and see what comes up.. You'll find lots of sources for in-wall wire. Blue jeans cable has some good info about what the codes actually mean and how they might affect what you are trying to accomplish. As others have said, you should check with your local building department to see how they interprate the codes before starting. Good luck!

Electricians point of view again! We just had the gentleman who installed the speakers at the Fleet Center, (soon to be called TD Banknorth Garden), come in for an audio tune up. The question of wire for speakers arose in conversation. At the risk of starting a wire war, his opinion was "some people think they hear a difference in the wire they use!" It is all copper after all. I'd do the Google search Steve suggested and buy a cable NOT based on a brand name. Save some money on the wire and splurge on the source. Jim

sraber,
I've not purchased any of their wire yet, but these guys' products look interesting. And at $1.40/ft. for 12/4 twisted pair, it does come in under your maximum, but just barely.

Jeff

http://www.knukonceptz.com/productDetail.cfm?prodID=KAR124BLS

I have to say the Fleet Center has an amazing sound. I've attended two concerts plus Bruins and Celtics games. Each time I've felt that I was sitting in my living room. I searched the Fleet Center website hoping to find some info on the design and equipment used in the system. No luck.

I saw garth Brooks play the Fleet many years ago. A few months after, I saw the same show at a venue in NC. It sounded so bad that I left 1/2 way through.

Avlis, all the concerts who come to the Fleet Center bring there own speaker and sound set ups tailored the way the show wants. Sometimes, like with AC/DC half the speakers hung by the stage are fake! The House speakers you hear at a game are Eastern Acoustic Works driven by Crown amps. Jim

Yeah, but nothin can beat the sound of the old Garden!

Yeah, I understand that musical acts bring their own gear. I'm interested to know what design/construction details went into the building structure itself because I heard a tremendous difference between the two venues. I always thought an arena would sound crappy no matter what. I assume some special effert went into the acoustics at the Fleet. Or did it just happen by accident?

The Fleet house sound is also amazing. I'm not a basketball fan but got free tix to a Celtics game. The player intoductions gave me chills (between the audio and video/lighting). Good stuff.

Yea nothing can beat the old of the old Garden! Fortunatly that sound didn't cause any of the old
Garden to fall on anyone!

I hope you went to a game after this fall because we found almost half the house speakers were disconnected! The only sound enhancement I know of is the black baffles hung between the rafters to keep the sound from reflecting off the steel ceiling. The sound engineer has a lot to do with how a band sounds on any given night. If the set up takes too long they may not have time for a sound check to dial things in. Jim

jeffdavis, thanks for the input. seems like an interesting option. i'd be interesting in what people who are currently using it say about it.

thanks again.

later,
simp