Four outs to six speakers

cruschkowski

I have just purchased a HK3490 Stereo reciver and whan to hook up 6 speakers to it. Since it only has outputs for 4 speakers I was wondering if I could hook 4 speakers into the B speakers for my mid and back speakers and then use the A speakers for my main fronts. Should this be done in series or parallel? I was going to do this by running my B speakers into a switch box so I could turn off speakers B1 or speakers B2. If I am correct this should be a parallel set up and the four B speakers would operate at 4ohms which the reciever is rated for. I am also going to run two powered subs off the jacks supplied. Does this sound like the right way to be hooking this system up? The speakers I am using are four M20 Polk Audio for the mid and rears and the fronts are Polk RTiA7's (which are bridgeable). The amp is 240w rms high current, so I'm sure the power should be there I just want to make sure I have the speakers hooked up right. Thanks for the advice, this is my first real stereo.

zingo

I would only run the matched number of outputs and speakers. Your receiver was designed really only designed to be a two channel amp, so if you hook up two speakers as rear channels, they would only be playing bipolar stereo, and not surround sound. As far as doubling up the speakers, you could overload the amp if you are not careful since amps are not made to drive more than one set of speakers from one output.

cruschkowski

bipolar stereo would be fine with me as I do have all the speakers and would like to put them to use. I'm not going for surround with this system, its for music only. I just dont want to ruin the reciever, but Harman Kardon does say the amp is 4ohm compatible so what I'm thinking is split with a parallel circut and all should be safe and well. I hope.

Knucklehead

Jake is right bro, I would be careful, you may find yourself down one channel.

cruschkowski

yea that wouldn't be good at all. kinda sucks as I have four new M20's. I did email HKardon and asked the same question. If they say its ok I'll let ya know.

kcoc321

IF you really must run all 6, I would suggest picking a Niles speaker selector (or eq) it is high current and has protection circuit esigned in so that the amp only 'sees' a 4ohm load.
Regarding A & B circuits, IDK about HK, but I know my ol' Denon 2 channel was actually designed to only run one set of speakers at a time (before I had the Selector) at least at full load. It did do 2 sets okay, but I never pushed it when I was running both (my 2nd set was on the deck).

Course for the $50 a good selector runs, you could probably pick up a half decent 5.1 receiver, at least based on the $$ on CL. Or just pick up a amp, if your HK has preouts.
Better safe than sorry.

cruschkowski

Thanks Kcoc thats some good advice. I was just looking at smaller amps (audio source 102) to run the two rear speakers, it has a bridgeable second set of speaker outlets so I could bridge and have a center speaker. Now that you mention speaker selectors, which I'm sure what I was looking for in the first place and I've went to there website I'm not to sure what I'm going to do. Its nice to know I have the options though. Not to sure what you mean about the 5.1 reciever though. I rarely watch a movie but wouldn't mind having a center speaker for TV. The speaker selectors with indiviual volume controls are a little pricey for what your getting I think but that would be the ticket for being able to adjust all sets of speakers individually. Thanks for the advice.

kcoc321

So does your Receiver have a Full Range preout?
IF it does, as a reference, I picked up a Parasound HCA-500 (50wpc/ 100wpc peak@8ohm) from CL for $50 one nice thing about the HCA Parasounds is they have gain adjustment. You can't make it louder than the volume level being fed to it, but you can adjust it lower, for like when you have the rear speakers closer to your listening position than the front speakers. 50wpc is not alot if you are going for chest thumping sound, but the M20's are just for ambiance anyway.

What I meant about the AVR is that you seem committed to running all 6 speakers. A 2 channel Receiver is not really made for that. You can always run it 5 speaker 'stereo' since you say you are not going for HT sound.

Where are you located? Maybe someone there has something you can tryout or at the very least keep an eye out for something that will work? What is your budget for these upgrades anyway?

I know it is hard to have speakers just sitting around, but in reality you are going to need alot more amps one way or another, to run all those speakers.

cruschkowski

Yes it does have a pre amp output and main amp input. I still want to use the HK as my main amp and would use a seconod amp just for the rears. Now my question is if I hook up an amp to the pre amp out put and nothing into the main amp input will they both work at the same time? I live in BC, Canada and am willing to spend what it takes to make this system work allthough I'm by nomeans rich. I spent $500 for the HK and that was all I was going to spend for an amp/receiver. I copied a bit out of the HK owners manual, mabey this will help you help me:

Main-Amp Inputs and Preamp Outputs: These jacks are
normally connected directly to each other with an included jumper.
Some devices, such as equalizers and some loudspeaker systems,
require connection between the Preamp Outputs and Main-Amp
Inputs, in which case the jumpers should be removed and stored in a
safe place for future use. You may also remove the jumpers if you wish
to connect the Preamp Outputs to an external amplifier, or if you wish
to connect another device’s line-level output directly to the HK 3490’s
power amplifier for a special application.

If you wish to use the HK 3490 with an external power amplifier,
remove the jumpers connecting the Preamp Outputs and Main-Amp
Inputs. Store the jumpers in a safe place in case they are needed in the
future. Connect the left and right Preamp Outputs of the HK 3490 to
the analog audio inputs on the external power amplifier. You may adjust the Volume and Tone Controls using the HK 3490’s
front panel or remote (volume only).
If you wish to install an external processor, such as an equalizer, connect
it to the Preamp Outputs and Main-Amp Inputs. Remove the jumpers
and store them in a safe place. Connect the HK 3490’s Preamp Outputs
to the processor’s analog audio inputs, and then connect the processor’s
analog audio outputs to the Main-Amp Inputs on the HK 3490.
Alternatively, you may connect the external processor to the HK 3490’s
Tape Monitor Loop.
I'm still not sure wether I want to use a speaker selector or anouther amp (I bought the HK for sound quality and if I could get a better quality sound from spiltting up the HK signal than from a lesser quality amp I would go that way, but as you say the rear speakers wouldn't be ran as loud mabey a cheap amp would be the way to go. I'm seriously considering the Audio Source amp 102 for $196Cdn with free shiping (50 w rms with outputs for two sets of speakers, and bridgeing on set for a front speaker) the only thing is I wouldn't be able to adjust the front and rear volumes seperatly as I would if I bought a selector with volume switches. I was also looking at the JEC TC-905 selector with 2 channels for input and five channels for output to run upto five pairs of speakers for $130 + $30us shipping, all the outputs have seperate volume controls

amp: http://www.rodinaudio.com/audiosource/img/amp102_detail.png
selector: http://cgi.ebay.ca/ws/eBayISAPI.dll?VISuperSize&item=220529666127

Thanks again for all the help. Any more comments or advice would be extreamly helpfull as it has been allready. I still haven't heard back from HK but I will post there reply when I do.

concealer404

If you're going to get a dedicated amp, i'd amp the fronts, since that's where your sound stage should be coming from.

cruschkowski

In case anyones interested here is Harmon Kardons reply:

You are correct, running both sets of B speakers together will be 4 ohms, but if you run them together with the 8 ohm speakers in speakers in speaker A, this will bring your impedance down below 4 ohms, which the receiver cannot handle. If you plan to run all six speakers at the same time, I would recommend that you use an impedance matching speaker selector box for the four speakers that will be connected to the B terminals. This will ensure that the receiver will see an 8 ohm load, combined with the 8 ohm load on speaker A, which will bring it to 4 ohms, which the receiver can handle with no problem.

dudeinaroom

If you are going to run a switch box get one with at least 3 sets of out outs, and impedance matching and run it off the A out put.. If you run all 6 speakers off the receivers out puts it would see a 2.6666666666666666666666666666667 ohm load(assuming that the speaker switches on the receiver are parallel.

cruschkowski

I did buy a seperator off Ebay for $129. It's a JEC TC906, inpedance matching with six sets of outputs, dual amp inputs and volume control. The other option I would have liked was to be able to switch the speaker sets off at the seperator but I am on a budget so I saved the 50 bucks and figure I can just turn the sets I don't want on right down. I'm not sure why you say to hook the seperator up to the A output of the reciver. My plan was to run my two main speakers straight off the receivers A outputs and hook the B outputs to the seperator. My other option is to hook both reciver outputs to the dual amp seperator and run all six speakers from there. I'm really not to sure which way would be best but thought going straight from receiver to sepeakers for my main set of speakers might be the clearest path from reciever to speaker.
Thanks for everyones help. If anyone could tell me the best way to hook up the seperator please let me know.

dudeinaroom

What impedance does the separator present to the amp?

cruschkowski

Good question and to tell the truth I don't know but here is what they say on Ebay:

Volume adjustment and impedance matching is accomplished through internal heavy-duty multi-trapped transformers for each speaker. This allows complete, independent control of each pair with maximum efficiency and virtually no generation of heat. The built-in precision auto impedance correction and overload protection circuits will safe-guard your amplifiers and speakers from damage due to excessively low impedance when all 10 speakers are playing at the same time.

High efficiency transformer based designed, fully automatic amplifier impedance protection
Compatible impedance with 4 - 16 ohm speakers

I'm thinking 8ohms from selector for B speakers and 8ohms for the front A speakers, which should be 4ohms at receiver. I'm not sure though.

bigaudiofanatic

Honestly man if you are just using them for stereo scrap the rear speakers. A better sound stage will be the outcome and you will not find yourself blowing anything up. Artists recorded their stuff for 2 channels not 4 channels. Also it should be like a concert where your music is coming from in front of you not all around "unless the concert dvd is surround sound and you have a receiver for that"

cruschkowski

I don't really want to scrap the rears as I allready bought them (just cause they were a deal at $300 for four). I was goint to set up the RTi7's and two of the M20's up front and two of the M20's for rear. When watching DVD concerts or listening to CD's ect. I was planning on running just the RTi's or running them with the one set of M20's that are up front depending on which sounds better. When I'm watching a movie or TV I was thinking I would just need the four M20's with the rears turned down and used for ambiance. I'm not looking for surround with movies just better sound than my TV, this system will be mainly used for music. Do you think I should run all four fronts when playing music or shut off my B speakers and let the RTi7's do there thing?

bigaudiofanatic

Than you are going to want a surround receiver not a stereo receiver.