RTi-A9 hook up

Tour2ma

tonyb wrote: »

True bi-amping is done with external crossovers.

Sorry, tb, hope I didn't get any on you...

btrots wrote: »

I'm also wondering what's best to set the active crossover at. The curve on the RTI A9's is quite a bit shallower than that on the electronic crossover I'm using. For lack of a better idea, I've padded the low and high-pass crossover point a bit to avoid a loss in frequency response. I guess worst case I'm losing a bit of efficiency to the passive internal crossovers in the speakers, but otherwise can't think of a significant downside

A reasonable approach to living with double filtering, but there's no reason to do so. "Efficiency loss" is minimal in any case and the supposed gains of external, active x-overs is more myth than reality. The myth goes something like this:

"When you bi-amp into a speakers' passive, internal cross-overs, the complete music signal is still amplified by all channels, so no power increase is possible... unless active cross-overs are employed between the pre-amp and power amp."

This is simply wrong and in a nutshell here is why: those that make the case confuse voltage gain with power output.

Take the extreme case of an amp with no speaker attached. While it still produces the same voltage gain/ differential as it would hooked up to your 9's, since there is no circuit there can be no current flow, and therefore the amp can do no work.

As you pointed out, cross-overs do not create walls at a designed frequency, but rather an ever steeper hill the undesired frequencies must climb. The hill (resistance) sends the current flow, and thus the power output of the filtered frequencies, plummeting. In other words the amp can only put ever reduced work into those frequencies.

Given that identical active and passive cross-overs will allow the same "unusable" signal to go to each section of a speaker, the only difference between passive bi-amping and active/ "true" (blech...) bi-amping is the minor amount of amp power that goes into heating of the capacitor resisting the current flow.

btrots wrote: »

Let me know what you think of the audible difference between bi-amp wiring and bridging, if there is one with the RTIs

You seem to be into experimentation and have all the flexibility you need, so experiment... Be sure to bi-amp both horizontally (one amp provides HF to both speakers; the other supplies LF to both) and vertically (one amp per speaker; one channel does LF and the other RF). I believe the latter to be the more sensible approach.

Also there's no reason not to play with the Crowns' active x-overs until you can hear a hole in the music from double filtering. Once you know where the hole becomes audible, move in the down from that point and see if you can hear where the improvement from your active filtering wanes...

tonyb

Can always count on you Bruce to get alittle splatter all over.

Bi-amping....external crossovers....technically speaking....doesn't necessarily mean it's the only way. More so a way to put some real estate between bi-amping and the so called bi-amp with receiver thing. Bi-amping in general has become a phrase used too loosely these days which most old timers take offence to....and in most cases rightfully so in my book anyway. The purest in this hobby will tell you the cleaner, simplest path a signal takes is the ultimate, and that any double filtering is frowned apon. Be it true or not, in the end it only matters what you hear, not what others think you should hear.The nice thing about audio is there is no rules of the road to follow, do what floats your boat. I would imagine in loose terms, that one must find a marriage between the technicals in this hobby and experienced opinion, if not ones own experiences.

Tour2ma

tonyb wrote: »

Can always count on you Bruce to get alittle splatter all over.

Thank you??? :redface: Don't you ever get sick of taking the high road? :cheesygrin:

Agree... so many paths to take. When I find a good one I just like to understand why it was good. But when I see a rationalization of why a path is good, or bad, that is based upon bad science, I just cannot let it go unchallenged.

First saw the knock on passive vs. "true" bi-amping years ago. It "felt" wrong, but I did not know why. I'd come close to an explanation a few months ago, but couldn't make a concise case. For whatever reason it just clicked in my mind this go-round...

Just my audio-cross to bear...

cr136124

michael1947 wrote: »

A week ago we had some conversations on this thread as to power for the RTI A9's. I experimented with several combinations and the best one I could come up was powering them with 2 old Kenwoods (150) wpc and was using an old Kenwood Pre. It worked, lots of base, lots of volume and they sounded pretty good but then someone mentioned that one of my 25 year old Kenwoods could take a dump and ruin some of my new speakers. Next week I expect my Emotiva XPA-5 will be here and my new plan is to run my front 3 with the 5 channel amp and use 2 of the 5 channels to bi-amp each of the A9's, 200watts for the highs and 200 watts for the lows. That would leave me with one 200 watts for my center. I will use the Onkyo for the backs and sides. I may have some more pointed/technical questions when I actually wire things up. For now I plan on the Onkyo txnr 708 to operate the Emotiva 5 channel amp as stated above...do you think I'm on the right course.

So, did you have the chance to drive your RTi A9s using the XPA-5 (bi-amp)? If yes, could you please share your comments?