how to wire two pairs of fronts?

hellotheworld

I'm just curious. I saw juice21's system in System Showcase. He put one RT35i on top of RT800i . That looks really cool. But I do not know how to wire them with one receiver. My receiver can connect two sets of speakers. A is for 6.1 and B is for stereo. When I connect one pair fronts to A and one pair to B, I can not use 6.1 system. I do not think the way shown in the figure below is correct. I only want to use A output which is 5.1.

steveinaz

You would be parallelling the speakers, causing an impedance drop. 2- 8 Ohm speakers would be equivalent to a single pair of 4 ohm speakers, might be an issue for your amplifier. Less impedance=higher current draw on the amp.

Brianomatic

What brand receiver do you have?

hellotheworld

So I do not think that's the right way to hook up. Is there a better way?
My receiver is Onkyo 501.

steveinaz

The cheap way is to buy one of the "black boxes" that allow you to add multiple speakers. The expensive (proper) way would be to run a seperate dedicated amp for your second set of speakers. Of course you could find some relative inexpensive amps to do this, Outlaw comes to mind. You'd have to split the main channel out from your pre with "Y" adapters.

Don't really know if it would be worth the hassle/expense.

Brianomatic

It appears he is biwiring using a special Monster Cable Biwire set similar op this:

http://www.monstercable.com/productPage.asp?pin=20

www.amazon.com/exec/obidos/tg/detail/-/B00004Y2VM/104-7545689-4679944?v=glance


If your speakers cannot be biwired per speaker design, you can biwire as follows. Be sure to purchase a biwire cable for full benefit.

There is two ways to connect more one speaker per channel: series or parallel.

Series:

For example, if you want to series connect two speakers to the front right channel of the amplifier.


1) The positive output terminal of the front right channel connects to the positive input of the first speaker (Rt35).

2) The negative input of the first speaker (Rs35) connects to the positive input of the second speaker (Rt800).

3) The negative input of the second speaker (Rt800) connects to the negative output terminal of the front right channel.

4) The total impedance of speakers in series can be found by adding impedances together. Series connections are easier on the amplifier than parallel connections because the total impedance is higher than driving a single speaker. For example, (2) four ohm speakers in series is a total impedance of 8 ohms load.

5) Repeat the above for the left channel.

6) This is a summary for only one channel

Amp Out (+) connects to Rt35 (+)
Rt35 (-) connects to Rt800 (+)
Rt800 (-) connects to Amp Out (-)

7) Repeat the above for the other channel.

_____________________________________

Parallel:

Amp Out (+) to Rt35 (+)
Amp Out (+) to Rt800 (+)
Amp Out (-) to Rt35 (-)
Amp Out (-) to Rt800 (-)

If Juice is using the special Monster Cable Biwire cable, in all likelihood he is going parallel. You must be sure that the lower impedance (half) does not cause the amplifier to overheat, shutdown, or blow the fuse. Wiring two 8 ohm speakers in parallel gives a load impedance of 4 ohms to your amp per channel. Thus check and see if your amp can drive a 4 ohm load per channel.

hellotheworld

en, I wouldnt do that:)

I just looked around the System Showcase and found someone using two sets of fronts.

Tour2ma

Parallel might raise current issues for the 501, as Steve indicated, depending on your listening levels.

Series is also an option, which raises the total impedance to the sum of the speakers' individual ratings. Safe for your AVR, but might not get you to te listneing levels you like.

Try both, just watch for signs of overheating the Onk during the parallel trial.

Brianomatic

Is your receiver the TX-SR501?

The specs show it can drive front speakers at 4 ohms at 125 watts thus you should have no problem paralleling the Rt35i and the Rt800 as front speakers since these speakers are 8 ohm speakers.

The Rt35i are rated at 8 ohm impedance:

http://www.polkaudio.com/home/library/downloads/catalog2000/13.pdf

The Rt800i is rated at 8 ohms:

http://www.polkaudio.com/home/library/downloads/catalog2000/13.pdf

Therefore, yes, you can parallel these two speakers as I shown you since your amp (if this is your amp) can drive a 4 ohm load.

You don't need special biwire cable. You can use two pairs for each channel. However, since the current the amp is sourcing will increase, I recommend at least 14 awg if not 12 awg.

steveinaz

Originally posted by Brianomatic
It appears he is biwiring using a special Monster Cable Biwire set similar op this...

This isn't 'bi-wiring" in the sense that we know it around here, he's trying to connect 2 seperate sets of speakers off 1 set of terminals..NOT a good idea unless his receiver is fairly robust...

Brianomatic

<<<This isn't 'bi-wiring" in the sense that we know it around here, he's trying to connect 2 seperate sets of speakers off 1 set of terminals..NOT a good idea unless his receiver is fairly robust...>>>

You can biwire either by having separate terminals build into the speaker thus separating speakers on one enclosure or by biwiring two separate enclosures. Same principle.

Biwirng is the use of two sets of speaker cables running from a single amplifier to the speaker. One set of cables is connected only to the high frequency section of the speaker and the other set only to the low frequency section. The choice of cable is made to optimize the performance.

With two separate speakers, the same can be done using Monster Cabke's Biwire cables to optimize the performance of the two pair. Nothing new here. Biwing two separate speakers this way is done all the time for improved frequency response and a more lifelike front channels for home theater.

Tour2ma

Bom,
I think Steve's just saying you can't bi-wire two pairs of speakers with one bi-wire cable per channel.

As for the 501's spec's, we've seen a number of 4 ohm capable AVR's bite it ona 4 ohm load, especially in HT.

htw,
Reread your intial post.

Are you saying that if you use both the A and B speaker outputs that 4 ch's of amplification would be in use for the twin mains?

If yes, this would be bi-amping and any issues with the parallel load would be moot.

Brianomatic

To biwire two pair of speakers to the front channels you will need a pair of biwire cables. Basically four conductors per channel.

I agree with Steve and you about being very careful paralleling speakers like this. I did mention to check to see if the amp can handle it. And you are correct, during home theater the dynamic range can be punishing thus driving speakers at 4 ohms or less at high volumes while watching a very demanding movie in regards to sound may damage the amplifier. Be careful by watching your amp closely at low volumes and then increasing slowing. An ammeter can be put in line also to monitor the situation until you are ensured the amp will deliver.

Repeating:

"You must be sure that the lower impedance (half) does not cause the amplifier to overheat, shutdown, or blow the fuse. Wiring two 8 ohm speakers in parallel gives a load impedance of 4 ohms to your amp per channel. Thus check and see if your amp can drive a 4 ohm load per channel."

hellotheworld

Thank you guys!
I do not want to use both the A and B speaker outputs. only A output.

I have tried to parallel two speakers for center channel and it worked. But I just tested them for a short time because I know that would half the impedance. I did not know that onkyo TX-SR501 can drive front speakers at 4 ohms and do not want to drive it too hard:)

I did want to connect two sets of fronts right now. Just curious how the other guys did that.

Brianomatic

HOM


Wow! 5 x 119 watts into 4 ohm speakers. Although, I would not drive all five at 4 ohms, it goes to show that driving only the front channels with 4 ohms shouldn't be a problem. Nice Receiver!


From ONKYO site, a review:

http://www.onkyo-emea.net/uk/cms/products/home/av_rec/TX-SR501E/indtip.htm

AUDIOVISION,
Germany,
2003/09

".... "This Onkyo receiver incorporates the latest equipment:…" "It really impressed the testers in the laboratory: being able to deliver 5x119 watt into 4 ohms is an amazing feature for this price category." "During the listening test the Onkyo stunned the testers with its airy and clear sound, which made everybody feel relaxed and comfortable. And even though there is no trace of aggression, it sounds still impulsive and lively. Its dimensional sound is very remarkable as it does not only put instruments and vocals in the right places it also separates dialogue and noises perfectly. "

hellotheworld

I just got my receiver several months ago and did not know that it was so powerful:) Some one recommeded it to me and said it's the proceeding version of classic onkyo TX-SR494.

Tour2ma

Just a thought, but if you invest in some dual banana plugs it might not be too difficult to swap between the A-B mode for amping four mains and the A-only mode for HT with only two mains. Would requiire reasonable access to the rear of your AVR.

hellotheworld

I just need to use my remote to turn off B:D

steveinaz

Originally posted by Brianomatic
You can biwire either by having separate terminals build into the speaker thus separating speakers on one enclosure or by biwiring two separate enclosures. Same principle.

No, it's not. Bi-wiring is done to dedicate a set of cables to the low-pass and high-pass portions of the crossover in order to reduce intermodulation distortion found in a single wire carrying both bass and mid/treble signals, simultaneously. Connecting 2 complete speakers with the same "split" cable does NOT accomplish this. You're still sending the entire signal down the same piece of wire. Bi-wiring has NO effect on impedance; and 8-ohm speaker is an 8-ohm speaker bi-wired. 2 seperate 8-ohm speakers hooked together are now a 4 ohm speaker, and none of the benefits of true bi-wiring have been realized.

Trust me, I've been doing this a few days....

PolkWannabie

Even bi-wiring in that fashion isn't going to accomplish the desired result as the full frequency of the signal will be amped for both sets of wires unless there's an active x/o ahead of the amp in which case now you're really actively bi-amping two different signals.

Brianomatic

<<<NOT accomplish this. You're still sending the entire signal down the same piece of wire. >>>

Same wire? Where are you? We are talking about 8 separate conductors.

All the big amp manufacturers understand this principle. Do I need to enlighten you? Do spme research instead of doubting an electrical engineer.

You need to research the big amp maufacturers, like Audio Research, SunFire, Etc. You can learn some great information.

I am only repeating what I have done and what good amps are capabilty of.

Brian

Brianomatic

Read the manual from Sunfire. Have you heard of Sunfire?

http://www.sunfire.com/pdf/Cinema%20Seven%20Manual.pdf

Look at chapter two.

Brian

PolkWannabie

LOL ... Yes I've heard of them ... See the diagram on page #13. Using the separate voltage and current paths by themselves will send a modified signal but it will not separate frequencies. Personally I don't like the current outputs for the highs, but some do.

||
\/

Brianomatic

I understand what you are saying PolkWannabie.

On the other hand, by biwiring two speakers to your front channels, your essentially making your front channels speakers larger. Although same signal, same frequencies. And like you said, to pass or reject certain frequencies you would need a crossover network which is basically filters, band pass and reject.

Some people like to increase the size of their speakers by adding two together. Maybe these people can be referred to as SDS SRS ( or 1.2 series) wannabies. lol

Brian

PolkThug

Originally posted by Brianomatic
[BSame wire? Where are you? We are talking about 8 separate conductors.

All the big amp manufacturers understand this principle. Do I need to enlighten you? Do spme research instead of doubting an electrical engineer. [/B]

When I bi-wire just one pair of speakers, I use 8 seperate conductors. So, If you are only using 8 seperate conductors for two pairs of speakers, then you would have to be running the high-pass and low-pass in parallel or series, right?

I think we all agree, we're just not communicating very well.

Regards,
PolkThug

Brianomatic

<<<I think we all agree, we're just not communicating very well.>>>

I agree. lol

The link to sunfire depicts the choices in biwiring either with a speaker like the SDA SRS that has the capability to biwire with the biwire ready terminals or by just biwiring two speakers per channel in series or parallel. By biwiring two speakers for one channel either series or parallel, both speakers will be receiving the same signal. By signal I am stating the frequency information being carried by the wire. To separate the low and highs you would need an external crossover and then only wire parallel with the lows coing from the crossover to one speaker (per channel, e.g. left) and the highs coming from the crossover to the other left channel speaker.

steveinaz

Take a look again, at the very first threads diagram. If you're telling me that this is an example of bi-wiring, you need to throw that engineering degree in the trash. And I'm using the term "bi-wiring" in the audio sense; not bi-wiring as in connect 2 speakers to the same output sense.

The way I read his post and original diagram shows me he is connecting 2 seperate speakers to the L/R output of his amp, AGAIN, this is NOT bi-wiring. He is not sending a signal seperated by an exlusive wire to a particular section of the crossover (the definition of bi-wiring) nor is he using an external crossover to achieve the same.

Brianomatic

I agree Steve. What Sunfire and HOW is referring to is real just paralleling more than two speakers to the outputs. HTW's diagram is only showing the left channel output paralleled to two speakers. He would then do the same to the right speaker. You are correct that this method isn't truely technically called bi-wiring.

As you know, some speakers are set up to be either biwired or biamped, like my SRS's. This is the true definition of bi-wiring. My SRS's support biamping/biwiring and have two pairs of terminals and some mechanism for shorting the two pairs together when used in the normal way. I am using only wire jumper for normal operation (uni-wire).

Biwiring means that a speaker is driven by two pairs of wires from the same amplifier output. One cable pair connects the high frequncy speaker terminals to the amp, and the other cable pair connects the low frequency speaker terminal to the same amp output that you connected the high frequncy cable to.

In conclusion, HTW is asking how to parallel four speakers to the same amp output's. This is paralleling speakers and not bi-wiring in the true sense. By Sunfire and me calling this bi-wiring caused this miscommunication, although many people used these words interchangably. HIW's diagram is correct. However, as you and I pointed out, it can be dangerous without using an amplifier that can source the higher current to a lower impedance load.

Brian

TheReaper

Originally posted by hellotheworld
I'm just curious. I saw juice21's system in System Showcase. He put one RT35i on top of RT800i . That looks really cool. But I do not know how to wire them with one receiver. My receiver can connect two sets of speakers. A is for 6.1 and B is for stereo. When I connect one pair fronts to A and one pair to B, I can not use 6.1 system. I do not think the way shown in the figure below is correct. I only want to use A output which is 5.1.

Hooking the second set of speakers to the B outs, and then listening to the As and Bs in stereo, is the best way to do it. Note: With the TXSR501, when you push the B speaker switch, it switches to stereo and uses the surround channels to power the B speakers.

But you want to run both speakers with the TXSR501 in surround mode. Your wiring diagram puts the speakers in parallel. With 8 ohm speakers this drops the resistance down to 4 ohms (like someone above said). The TXSR501 is only rated for 6 -> 16 ohm speakers (RTFM), the 4 ohm rating is a dynamic power rating (FUD). So if you want to run the speakers in parrallel, you either have to add in a 4 ohm audio resister before you split the wires on one of the terminals, or you have to get a speaker selector switch which adds in 4 ohms of resistance.

Asking that poor little TXSR501 to power 2 hungry speakers off one speaker terminal, is asking a lot. It will do it, but you might not have quite as much volume overall.

How most people would do what you want. Would be to get a receiver with pre-outs. Then connect the pre-outs to a separate power amp to power the second pair of speakers.

Frank Z

The reaper brings a thread back from the grave.:D

scottvamp

Originally posted by TheReaper

But you want to run both speakers with the TXSR501 in surround mode. Your wiring diagram puts the speakers in parallel. With 8 ohm speakers this drops the resistance down to 4 ohms (like someone above said). The TXSR501 is only rated for 6 -> 16 ohm speakers (RTFM), the 4 ohm rating is a dynamic power rating (FUD). Asking that poor little TXSR501 to power 2 hungry speakers off one speaker terminal, is asking a lot. It will do it, but you might not have quite as much volume overall.

How most people would do what you want. Would be to get a receiver with pre-outs. Then connect the pre-outs to a separate power amp to power the second pair of speakers.

B-I-N-G-O was he name O!!!!

Nice going reaper - bringing real knowledge to the tread. I have been down this road already. Rt35's on top of my rt1000p's.
This Onkyo is considered an ENTRY level reciever on the Onk line and should NOT be driven at 4 ohms period. Do it right if your going to do it with that receiver and use the pre-outs and another 2 channel amp........ Seeing as you have an entry level reciever I do not see you going down that road.
16 ohm setup will not give the sound you want.

We seem to always confuse "bi-wiring" and "bi-amping" both are very simple in reality.
In bi-wiring in the sence that you have two seperate speakers, you have parllel which cuts ohms in half and in series which doubles them.
Bi-wiring in the sence that have a single speaker is simply just two runs of wire to a single channel.
You've been served!!!!!;)