bi-wiring via surr. back/ zone 2

[obieone]

I've got a Denon 1905/785, 7.1 recvr. It has a separate amp. for surr. back or zone 2. Question's: 1. can I bi-wire from these channels or is it even noticable? If yes, A ch. on top posts & zone 2 on bottom posts ? OR
3. zone 2 top posts, and speaker level thru sub to bottom posts?
I just picked some T90EB's and am trying to tweak them without getting that puff of blue smoke in the living room. Thanks for any feedback;)

[John K.]

Obie, welcome. The first point is that you've got the terminology a bit tangled-up: you use the term "bi-wiring", but it appears that you're actually thinking of "bi-amping", since you think that the 1905 has a "separate amp" for the surround back or zone 2 speakers. This is incorrect; the 1905 and nearly all other receivers have only one amplifier, which contains several separate channels of output transistors which operate as valves to measure out the power required to the connected speakers. Connecting previously unused surround back/zone 2 output transistors to either the top or bottom posts of your speaker can't create any more power than the one power supply section in your receiver had before; the same amount of power would simply be fed to the speaker through two sets of output transistors rather than one. Actual bi-amplification requires two separate amplifiers with separate power supply sections and separate external crossovers before each amplifier to be effective.

So, although you wouldn't be getting a "puff of blue smoke", neither would you be getting any benefit. Relax and enjoy your music.

[obieone]

thanks for clearing that up. I think I'm done trying to tweak my system. I'm just going to enjoy it.

[cambir]

refer to page 42/43 of your receiver's manual (http://usa.denon.com/AVR-1905_785_ownersmanual.pdf) to consider figurations for a zone 2 (also noted on the product sheet).

I would argue that with this Denon and many others, you can actually seperately power a set of speakers from your surround back/zone 2 terminals. Correct me if I'm wrong, but the end result would be bi-amplification?

However, I think you may run into more of a problem attempting to play the same source on both zone 1 and zone 2 at the same time as you have to select a specific source to play out of zone 2. Your zone 2 volume control may also be independent.

[John K.]

No Cambir, despite any language in the manual, as my previous reply detailed, simply connecting unused channel output transistors to one section of a speaker isn't actually bi-amping. The transistors don't have any power of their own; they simply distribute the power from the one power supply section. Two separate amplifiers would be needed.

[cambir]

Why would Denon use this language if it was not able to do exactly that? This implies those channels do actually have power of their own.

Denon 1905 Product Sheet:
"The Denon AVR-1905's Power Amplifier Assign function let's you assign the Surround Back amplifier channels when the system is not configured for 7.1 to instead drive the Multi-room Zone 2 speakers, with 80 Watts per channel output power, while still providing 5 discrete amplifier channels to drive all speakers in the 5.1 configured home theater room."

I have looked into this option for powering my zone 2. This allows you to power a 5.1 in zone 1 (main room) AND an additional 2-channel in zone 2 (another room). If you can power a zone 2 with an independent 80 watts, then you could, in theory, assign that power to whatever speakers you want.

I would say it's not really worth the effort, and not true quality bi-amping, but I would still argue that it is possible to do with this Denon. Only way to find out is to try. Has anyone attempted this zone 2 option with their Denon?

[Kex]

No Cambir, despite any language in the manual, as my previous reply detailed, simply connecting unused channel output transistors to one section of a speaker isn't actually bi-amping. The transistors don't have any power of their own; they simply distribute the power from the one power supply section. Two separate amplifiers would be needed.
+1 ... This is exactly right, IMHO.

P.S. Shame on Denon for using such ambiguous language.

[obieone]

I would like to thank all those that replied to this thread. But, as it turns out, after setting the T90's thru the sub, adjusting vol/ LFE, I get bloody ears @-10db with another 25db to go!!!
Sooo... as far as amplification goes, I think I'm ALL SET!
tHANKS.

[F1nut]

You're getting bloody ears at -10dB because the AVR is running out of steam. You don't have another usable 25dB to go. Every AVR or power amp has a power band or range of usable power. Just because a volume scale goes from 0 to 100 (example), it doesn't mean you'll get clean power at the 100 setting, you won't, it'll be nothing but distortion. I would venture to say that -10dB is about as high as your AVR can go without going into the clipping (distortion) range because right on the edge of clipping is when people's ears start to bleed.

Anyway, it seems that you're happy, enjoy.

[soundstage3000]

I just bought the rti12's I have a pioneer vsx74txvi powering them am I benefitting from biamping or just hooking them up normal Thanks in advance