First Xenon, I largely agree with you about bi-wiring. The only arguments that I have heard that favor bi-wiring beyond the wire gauge involve claims that certain frequencies are handled better by different types of wire (twisted vs solid etc). This is well beyond my level of hearing and I would make not claims there. However if one does drink that kook-aid then removing the shorting strap is part of the path to the promised land.

Second, I believe there could be merit in passive bi-amplification in some instances. As I stated, I don't know if that applies in RCubes case. I think we can agree that as long as RCube has unused amplifier channels, his cost for experimenting is largely minimal (possibly for wire and otherwise only for the time expended). And yes there could be an impedance issue (but I doubt it as the manual describes a 4 ohm minimum and does not specify a lower minimum for bi-amplification setups, which they would probably do if there there was an issue). Nonetheless, I agree that RCube should check with his dealer, or the manufacturer, before proceeding. But having done that, if there is no danger, then there is little reason not to try. Certainly he will increase the power available to the woofer and double the total overall. In my previous experience (admittedly with a much less efficient speaker than the OMD-15's, Dalhquist DQ-10s and one which did not involve bi-amping) increasing the power from 100 wpc to 205wpc made a significant difference in my fairly large room. If his room is small to medium, then perhaps this isn't necessary but RCube didn't provide that data. Nor is this as case of an untested setup as RCube described how "phenomenal" his system sounded. Consequently, I see no reason, not to try or why, given all of the money spent in audio chasing the last small percentages of improvement, that a little to no cost option should be automatically argued down.

Sorry Sirquack, but I do understand the difference between active bi-amplification with external electronic crossovers before the point of amplification and passive bi-amplification where two separate amps are fed the same signal but are presented with different circuit loads because they are handling different speakers. I have also read a fair amount of the stuff on the internet about this including the old posts by Soundhound on the benefits of multi-amping his fully active system. And in this case when I have my facts straight as I believe I did and do, and someone asks "if Bi-wire or Bi-ammping would make it any better", I take your response "He is talking about Buywiring, not biamping. Even if he was attempting biamping, unless it is done correctly there is little to know benefit." as griping.

RCube: What ever you do, I am glad you are enjoying your system.

I saw a few illustrations that might come in handy when describing one benefit to bi-amping. The images are on a page Copyright © James L. Tonne 2009 called “The Pulse-Width Modulator with an emphasis on the post-modulator lowpass filter” and found at this web address:

http://tonnesoftware.com/appnotes/pwm/pwmham.html

While his information is well beyond what is being discussed here, three of the images are pertinent.

In order to see the images in this post, right click on the link above and select 'open in new tab', come back to this page, refresh this page, and if there are X's where the images are supposed to be, right click on each X and select 'show picture'.

Image LowF:


Image HighF:


Image Fsum:


Simplistically . . . In both the high frequency and low frequency images, the voltage range is just shy of two volts. When the high and low frequencies are combined, the total voltage range effectively doubles to just shy of four volts. If the high and low frequencies were bi-amped, one could use two amplifiers where the total voltage range for each individual amplifier was three volts and still have plenty of headroom. If the combined signal were sent to a single amplifier, the amplifier would need to have a total voltage range of six volts in order to have the same percentage of overall headroom. If I double the output voltage into a simple resistance load, four times the power will be used. If reality were this simple, I could replace one 200 watt amplifier channel feeding a passive two-way loudspeaker with a two-way pre-amplifier crossover and two 50-watt amplifier channels, each channel appropriately driving either a tweeter or a woofer.

In most music that has a mix of instruments, the amplitude of the higher frequencies by themselves is less than the amplitude of the lower frequencies by themselves, so sums of equal-amplitude high and low frequencies are not usually found. This means the example above shows an exaggerated disparity between pre- and post- amplifier crossover use. Then again, the inefficiencies of an after-amplifier passive crossover network makes the example a little less far-fetched.

Some powered two-way loudspeakers that use an active crossover will have internal amplification that provides about 50% more available power for the woofer than for the tweeter.

We are heading down the "Clever Little Clocks" path here. I agree that the experimental connection of bi-amping could be tried but I don't believe it will make a "phenomenal" system sound better. Why negate what the Mirage folks have built as a system. Why not just connect something like a Bose 901 to one channel and a Heil AMT to the other side and do away with the crossovers altogether. The Bose will handle all the stuff above 80 hz up to around 4000 hz and the Heil will carry the load from there. Remember that the design folks had specific ideas in mind when they designed the crossovers for the size box containing the drivers.

Again, I would spend some time listening to the system as is and if I was not satisfied or a bit curious I would try the bi-amping connection. Like 73 said it is a cheap experiment and it might give a sonic advantage. Definitely verify the specs with the dealer or with Mirage themselves (get it in writing if you can).

Thanks to all that have responded especially, Sirquack, 73Bruin, Xenonman and Gonk. reading all your comments, I have just wired my speakers using a single pair (no bi-wire/buywire or bi-amp), as Xenonman stated, as I am using a decent enough sub I really do not see a need to bi-amp my speakers and if I set my speakers as small in the pioneer AVR configuration most of the bass heavy lifting is done by the sub (now that is another discussion whether to set the mirage omd-15s as small or large in the configuration) also I am using 12 AWG speaker wire and it is a bitch to move the 7125 from the built in wall shelf. My room size is 12x20 in my basement, I have created a dedicated HT area. Will post pics soon.

In any case the 7125 shows no signs of sweat running the mirage omd-15s, and I would know more in a couple of days once I am really able to crank it up, as currently i am in the 100 hours of the recommended break-in period.

Thanks again, All have a great Memorial Day weekend.

RCUBE, most processors need the mains to be in the "small" mode in order to activate the bass management system. With the mains in large you may not get a signal to your sub. Some let you choose to have both signals at the same time. If you get both signals you will likely have more bass than you want (or not). Since you have the sub and it will do the heavy lifting, you can save headroom on the 7125 for the mains by setting them to small. Looking forward to your pix.

Thought I'd pose my question here rather than start a new thread.

I just ordered the 7125, the sale price was too good to pass up. I'll be running Paradigm Monitor speakers for the front sound stage. I've read that the 7125 is very neutral with slightly relaxed highs. My pre-pro will be the Onkyo 876 receiver, which is a little forward. I'm expecting a little less of the Onkyo forward sound and more dynamics from a dedicated amp. Is that about right, or any comments on my set up?

I know that this part of the forum doesn't get as much action, why don't we all change that. Outlaw IS an amp company first, after all...

Hey Sharkey, your assumption sums it just about correct.

The 7125 will be neutral AND more detailed. I myself have an Onkyo 906 and I am running it as a pre/pro to my 7500. I noticed detail from the Outlaw that was not present even on the 906. The speed and reaction time of the amp is much greater than an AVR. The damping factor alone controls the speaker drivers with speed and precision. Surround sound detail improved as well. Once you go to an Outlaw amp you will be saying goodbye for life to AVR power.

Excellent move on the 7125. Please let us know your thoughts when you get it.

Good to hear from another using an Onkyo AVR as a pre-pro. I was wondering about the increase in things like the damping factor, S/N ratio and THD%. I won't have to wait too long as I got the confirmation email today.

Hi all
I have a 7125 and a Onkyo Receiver, running a Polk audio LSIc and LSI9 speakers.Boy, your in for a treat.Music is full.
Blu-rays are breath taking. Enjoy your purchase, I love the 7125 amp.

I ordered the 7125 on the 29th of March, but due to somewhat of a backlog coupled with a long weekend, my amp was received by Fedex only yesterday. To double my trouble, I'm out of town on work and won't be able to try it out until the 28th of April. The suspense is killing me!