# How to Bi-Amp with a Single Receiver?



## novaphile (Nov 16, 2012)

Hi people,

I'm looking to Bi-Amp a pair of Tannoy Revolution R2 speakers, and I'm wondering if it can be done with a single receiver...

The Receiver is a Rotel RSX-972.
It contains five separate 75 watt power amps -- one for each channel (front left, front right, rear left, rear right and centre).
Currently it only has a single pair of speakers connected, leaving a lot of channels for trickiness... 

It has six pre-amp outputs, and myriad of inputs, including a set of six 5.1 channel inputs (these sets are the same as above plus sub-woofer).

Any analog source can be set as the Recording source (outputs the source signal to any recording output -- tape or video 1 to 5)
Any source can be set to the listening source (outputs the source signal to speakers) 

Here's what I'm hoping to do:

1. Select a stereo input source (typically CD or built-in tuner) as the "Recording" source.
2. Output to a mini DSP unit (using the mini DSP as an active crossover).
3. Take the Low Frequency L/R and High Frequency L/R back to the Receiver. 
For example: LF-left to 5.1 Left Rear input, LF-right to 5.1 Right Rear, HF-left to 5.1 Left Front, HF-right to 5.1 Right Front)
4. Connect the matching speaker outputs to the separate input terminals on the speakers (LF direct to the bass driver, HF to the passive cross-over between the mid driver and tweeter)
5. Set the 5.1 inputs as the "Listening" source.

Can anyone offer advice about the possibility of achieving this?

It doesn't look like the manufacturer's intention, but there are a lot of connections (and circuits) sitting idle at the moment.

Andy


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## hjones4841 (Jan 21, 2009)

Is the recording source output fixed level? If so, how would you control the volume? I am not famiiliar with the Mini DSP, does it have a master volume control?

What problems are you trying to correct by bi-amping, or is it just to try to see if you can get better sound? I would think that most speaker manufacturers select passive crossover frequencies and slopes for best performance.


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## novaphile (Nov 16, 2012)

hjones4841 said:


> Is the recording source output fixed level? If so, how would you control the volume?


I'm hoping that I'll be able to use the volume control on the receiver to vary the volume at the power amp stage.



hjones4841 said:


> I am not famiiliar with the Mini DSP, does it have a master volume control?.


I'm also not familiar with the unit, I'm just starting to find out how it works



hjones4841 said:


> What problems are you trying to correct by bi-amping, or is it just to try to see if you can get better sound? I would think that most speaker manufacturers select passive crossover frequencies and slopes for best performance.


Bi-amping is recommended by the manufacturer.

I'm happy with the way the system sounds now, but am experimenting to see if I can get better sound from these speakers.

I'm also conscious that the Receiver has a lot of functionality which is not being used.


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## Jungle Jack (Jul 28, 2009)

Andy,
Many 7 and 9 Channel AVR's offer Biamping options and some even offer Bridging. However, I do not think any 5 Channel AVR's offer this feature. It makes sense for a 9 Channel AVR to offer these options as a very large percentage of folks use 5.1, but with only 5 Channels Biamping does not make sense for a vast majority of applications.
Cheers,
JJ


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## novaphile (Nov 16, 2012)

Thanks JJ, I'm aware that the receiver doesn't do this natively. 

I'm trying to see if I can achieve the same result with a bit of tricky connecting.

I'll see if I can upload a diagram showing what I'm trying to achieve.


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## novaphile (Nov 16, 2012)

OK... here we go...










My concern, looking at the info available on the Receiver. Is that the signal coming back in has already been through a pre-amp stage. I worried that putting it back through a pre-amp again before getting to the power-amp stage, could cause problems.


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## novaphile (Nov 16, 2012)

Weird, I can see the image link in the post (in editing mode) but can't see the image...

I'll have to poke around and see what I'm doing wrong.


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## novaphile (Nov 16, 2012)

OK, hopefully the image is attached to this post.


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## JoeESP9 (Jun 29, 2009)

From what I see of your diagram it won't work. The record out from your receiver will track whatever source you've selected. In your scheme, selecting the 5.1 inputs for playback would also put them on the record out connections.

If you could separate the preamplifier and power amplifier sections of your receiver you could get it to work. You would use the preamp outs to the Mini DSP and then to the power amplifier inputs. Otherwise no.


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## novaphile (Nov 16, 2012)

JoeESP9

The Record output and Speaker output are selected separately. 

It is simple to listen to one source while recording from another.

I'll try connect a component to these inputs and see if it is still possible to select a "Recording" source.


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## novaphile (Nov 16, 2012)

Test was successful.

It was possible to select "5.1 channel" as a Listening source (i.e hear it through the speakers) while recording a different signal as a Recording source.

The source (mp3 player) was quiet, so it's possible that the 5.1 source skips a pre-amp stage, if this is true, it's ideal for my purposes.

I think I'm just going to have to bite the bullet, get the mini-DSP configured, and give it a try.

Andy


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## djbachelor (Dec 16, 2009)

Hi Andy, I just stumbled across your thread and am interested to see if you got the mini-DSP and if this approach worked for you?


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## novaphile (Nov 16, 2012)

Yes. I did get it working.

I ended up using the zone 2 output as the feed in to the miniDSP...

It worked, but there were a couple of problems.

Some internal interaction meant that I could not use the tuner anymore. 

The receiver kept forgetting the output volume to the miniDSP. 

I've subsequently bought a separate pre amp and four channel power amp to use with the miniDSP and I'm very happy with the results.


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## djbachelor (Dec 16, 2009)

Ok, thanks for the report.


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## 8086 (Aug 4, 2009)

Two simple ways you can do this:

Buy a newer receiver with 7.1 or better. Pioneer Elite SC-68 is what I would recommend. 
Buy an emotiva splitter and 5 channel amp.


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