Technical question. 5.1 to Active 4.0

Since you're considering actives wouldn't it be better to run optical-out from the av amp to each speaker rather than using the av amps built in DAC and amp?

 Then the av amp just becomes an av processor.  You can still use RCA for the sub or even a centre speaker if needed later.

Not aware of any AV receivers able to deliver the deoded/processed channels out separately via optical connections, and of course the speakers won't be able to decode a surround datastream and allocate it to the appropriate speakers.

This processor can deliver each channel as a digital out, as I noted in this blog, but I fear it may be a little beyond the budget! So the best way is indeed to feed analogue outputs from the receiver/amp's preouts to the appropriate speakers, and run the processor in 'phantom cetre' or 'no centre speaker' mode so that centre-channel information is steered to the front left/right speakers.

Or buy another pair of active and run 6.0! Why is the sub being dropped incidentally? It doesn't need to be just because the rest of the speakers are active.

I know Andrew has already addressed that post, but I just have to say that doesn't make any sense at all! It isn't technically feasible beyond the Datasat, as Andrew has explained. XLR outputs would be the better option, perhaps that's what you were thinking of, though these are still an analogue connection, but since the OP's receiver doesn't support them, that's not an option anyway.

You don't mention what actives you were thinking of going with? Very few full range speakers will adequately cover the sub's frequency range - so I wouldn't dispence with a sub just yet.

I also wouldn't dispense with a centre channel either, unless your front speakers are quite close together.

Also the overriding question has to be; what are you trying to achieve with this change? If we know what your objectives are things become a little clearer to offer advice on.

Thanks for all the input. 

My main reason for doing this is mainly to simplify things and get rid of some wires, although in reality not that many. 

I propose to use my AVI ADM40s at the front and a new pair of ADM9s as rears. 

The room I use for TV is quite small (c.12'x12), so feel that a sub may not be needed, as the ADM40s have great range. I'll assess the sub situation when it's up and running. 

My understanding if  I use the pre outs I'll use the DAC on the Yam, but the amplification of the speakers. This is another consideration. How would I set the speakers volumes. 

The front speakers are only about 5-6 feet apart, so setting a phantom centre should be fine. After all when watching stereo broadcasts vocals etc don't sound different from watching a film with a dedicated centre. 

The more input the better. Thanks. 

Yes, that's correct on the DAC/amp split. IIRC the ADM speakers have a 'bypass' setting, enabling you to set them to fixed gain for just this purpose, though the manufacturer would be able to confirm whether this is the case, and how you access this feature. It would simply be a matter of selecting this mode, then running the set-up on the Yamaha to get the appropriate levels for surround.

Assuming you're running other sources directly into the speakers, it's then just a matter of ensuring the 'bypass' mode is engaged on the speakers when you want to watch surround content, and letting the Yamaha control the levels.

If they're that close together then I'm pretty confident 'phantom centre' working will be fine.

Thanks Andrew. 

I'd use passives for the rears...

Why?

Because he already has an AV Receiver and the benefits of an active crossover for the amount of content in the rear channels feels marginal to me, together with the fact that it adds complexity from a cabling and power point of view, especially at 1200 quid.

EDIT - my English is all messed up.

I'd keep the passive 5.1 setup...

Good point about the extra power cables. It's true that there's limited content in the rears, although if cost is not a consideration (as it appears not to be) then the benefits of tonal consistency may be considered worthwhile. 

Now that is embarassing - my av amp does only have a single optical out per input .

Is it that difficult to build a decoder that splits an optical signal into the various channels and outputs them all via optical?

Not a clue, beyond the fact that the Datasat I mentioned above is the only processor I know that does it, and even then it's electrical digital, not optical.

I guess the mass-market processor/AV receiver manufacturers would say there's vanishingly small demand for such a provision, given that it'll need extra DACs on each channel downstream of any such digital 'preouts'.

Re. The whole cost thing. I'm pretty sure that sales of my MA 5.1 will more than pay for a pair of adm9s. 

The locations of sockets in the room make it very  easy to plug in rears, instead of 2 pairs of speaker cables I'll just have one set of interconnects going around the room. 

The 40s and 9s hav bypass so you can set the gain and let the processor control the volume. 

I'd have my BDP, ATV, Sky HDMI ins to the Yamaha and probably my Sonos connected via optical straight to the speakers