BI-AMPING

[redrocker]

I have RF-25 in my 5.1 system with Denon 3806 AVR & need to know if I can safely bi-amp these speakers.

[33klfan]

Welcome to Klipsch forum,

I think what you mean is bi-wiring. Bi-amping is taking two amps, one amp driving the woofers of two speakers, and the other amp driving the tweeters of the speakers. What you are talking about i'm sure is connecting both binding post on the speakers to your denon avr. This in a sense is the cheater way of bi-amping and supposedly helps with sound improvements by connecting two pairs of wire to one amp. Now if you are talking about bi amping, you would have to use another amp, like how i said above. It can be done, but i don't know all the technical stuff involved. It is safe, you just have to watch the output power of the amps so it won't blow out your drivers. Some others should fill you in here. Let me know which it is your trying to do.

[wuzzzer]

Most of the Reference series floorstanding speakers are designed to be either bi-wired or bi-amped. In your case, you'll need another amp to bi-amp. If you're looking to bi-wire, the benefits are typically unnoticeable.

[DrWho]

Just make sure you first remove the jumpers between the binding posts. But yes, they're safe to biamp.

[redrocker]

Biamping is what I need to do. The Denon's have seperate amps for each channel and the manual shows how to do it, I just needed to know if I could safely do it with these towers. I hope DrWho answered correctly because biamping will boost the max wattage to 250 w. each, the speakers are rated @ 125 watt each.

[TBrennan]

Bi-amping is the practice of splitting the signal into highs and lows BEFORE the amplifiers and then having one amp do LOWS ONLY and one amp do HIGHS ONLY. This can be done either actively, with an active crossover between preamp and amps, or passively, with passive filters between preamp and amps.

The dubious practice of sending two fullrange signals to the seperate legs of speaker level passive crossovers is often known to old-time real bi-ampers as "fool's bi-amping". ;-)

Nor will sending 125 watts to each leg of the passive crossover result in a doubling of usable power, note that at a given frequency only 125 watts is available, not 250. Will you gain a little headroom? Maybe. In any event you're not getting what you think.

[redrocker]

Bi-amping is the practice of splitting the signal into highs and lows BEFORE the amplifiers and then having one amp do LOWS ONLY and one amp do HIGHS ONLY. This can be done either actively, with an active crossover between preamp and amps, or passively, with passive filters between preamp and amps.

The dubious practice of sending two fullrange signals to the seperate legs of speaker level passive crossovers is often known to old-time real bi-ampers as "fool's bi-amping". ;-)

Nor will sending 125 watts to each leg of the passive crossover result in a doubling of usable power, note that at a given frequency only 125 watts is available, not 250. Will you gain a little headroom? Maybe. In any event you're not getting what you think.

OK, I appreciate that info.

Although, it just takes connecting a couple more cables......will I notice a difference? If so, how little would it be?

worth it or not?

[jacksonbart]

I have nothing to add

[Ragamyers]

I'm someone who biamped my RF-7's with my Denon 2106 using the 6th and 7th channel amps, thinking that it would provide headroom for my low-frequency woofers(the Denon receivers will allow this). In fact, I've learned since, there's still only 100 watts available to the woofers of the tower, causing almost zilch difference from the original wiring scheme. Hope this helps.

[jimmy4300]

I'm someone who biamped my RF-7's with my Denon 2106 using the 6th and 7th channel amps, thinking that it would provide headroom for my low-frequency woofers(the Denon receivers will allow this).  In fact, I've learned since, there's still only 100 watts available to the woofers of the tower, causing almost zilch difference from the original wiring scheme.  Hope this helps.

I hear you, but I don't understand??? I am setting up an HT with only front speakers, RF-82s and an RC-62. I also have a Denon Reciever (AVR1907) 85 watts X 7 channels. I am planning on bi-amping the 82s with the scheme you are talking about. Why wont 2X85 give me 170 watts per channel? Four separate amps will be driving two speakers??? What am I missing?

Lou

[TBrennan]

Red---Well it's easy enough to do and it certainly can't do any harm. Try it and see what you think.

[TBrennan]

Lou---It's like this. If you feed one amplifier channel of 85 watts to your speaker you have 85 watts available at any and all frequencies, let's say from 20hz to 20,000hz. You have 85 watts at 20 hz and 85 watts at 20,000.

Now let's say you have a passive crossover at 2000hz and you're feeding each leg (one leg the low pass and one leg the high pass) with a seperate 85 watt channel. You still have only 85 watts available at any given frequency, not 170. That's because only 85 watts is going to above 2000hz and only 85 watts is going to below 2000hz. Just as above you have 85 watts at 20hz and 85 watts at 20,000.

See what I mean?

[mas]

Whoa! I know that I have far too many things that I should be doing, both on the forum in other areas and in my own life to dive into this, but I can't seem to resist a train wreck with so many running in so many different directions and using terms in so many different ways! []

Allow me to be a smart aleck first, and then I will try to clarify this Gordian knot...

We are confusing many issues here! I have a 100 watt space heater, a 75 watt light bulb, and a 35 watt toaster in my house... But I am not inviting folks over for them to listen to my 210 watt appliance ensemble... (...Let's just say I am barely managing to resist the temptation! [] )

You are confusing wattage in the form of disappated heat with sound pressure levels!

Regarding bi-amping... this is really a rather simple concept once the confusion is cleared up. A multi way system can be split into several sections, usually dependent on how many 'ways' it is - meaning how many different frequency bandpass 'elements' it employs. Thus a 2- way system would emply some manner of LF-MF driver stage and a MF-HF driver stage. A 3-way system would employ a LF driver stage, a MF driver stage, and a HF driver stage.

(Bi/Tri)-amping involves taking the 'all-pass' output of the preamp, passing it through an active crossover to split the signal into distinctly separate frequency limited passband signals, each exhibiting an upper and lower bound, decay slope and a time component - thus the result is a passband for each stage in the speaker system as mentioned above. Each of these discrete signals is then fed into an amplifier stage and then fed to the respective 'stage element' of the speaker assembly. Thus, for a 3-way tri-amped system the LF signal passband would be fed to an amplifier and then to the LF stage of the speaker assembly. The MF signal passband would be fed to an amplifier and then to the MF stage of the speaker assembly, and the HF passband would be fed to an amplifier and then to the HF stage of the speaker assembly.

The purpose of this is not to make the system have greater gain ('volume'). Rather it offers opportunities for alignment of the various stages within the time domain as well as reducing the complex load on each amplifier. It is 'easier' for an amplifier to accurately reproduce a signal with a frequency constrained limited bandpass than it is to reproduce a wideband signal.

Multi-way 'amping' also allows you to more effectively and efficiently allocate resources within the system as well. For instance, a lower efficiency LF section may benefit nicely by having say 300 watts available to drive it while the higherr efficiency mid and high frequency stages each require substantially less power. But this does NOT mean that the acoustical output is the sum of the power ratings.

Oh, I guess you can say this, and it is common in such niches as the insane automotive market audio competitions where this nomenclature has absolutely no meaning except to impress other adolescent sensibilities (regardless of age). Hence you hear of the 50 quadrillion watt car stereos that are supposed to impress someone! - [sorry! I am just having a bit of fun here and excercising my demons.[] IOW... Yes, I am being a smart @ss! I mean no harm - I am just temporarily off my meds and the tryptophan from the Thanksgiving turkey is starting to wear off! [] ]

But more seriously...The total SPL levels experienced will not be a function of the totalled wattage of the respective stages. They will be a function of the sensitivities of he various stages and the net balance between them.

You 'bi-amp' for the potential for increased clarity and time alignment. It is most commonly employed in larger Sound Reinforcement environments where it is the norm. But are you going to necessarily realize a dramatic increase in the audible difference in a home system? No. Does it offer the potential for increases in certain respects. Yes. I will make a few mad by saying that it is a valid tool and I do have a preference for it compared with passive crossovers, especially with systems that exhibit a large time offset such as in the Heritage line, but I am not going to say that it is the most cost effective nor significant ROI that you can make.

(On the other hand, you 'bi-wire' because the description in the brochure sounds wonderful!)

Thus there are valid reasons to consider bi/tri-amping, but it is equally important to understand what it will not do!

You do not do this because it will give you 'more watts'! Done properly, you will probably not notice ANY difference in gain/SPL levels. And each stage will actually work more 'easily'.

Hope this helps a bit... []

[pauln]

There is a very easy and direct way to bi amp that I have never seen mentioned... or maybe this is the way everyone has been doing it but just haven't spelled it out?

Start with two stereo amps, one for each speaker. Use each amp's left and right channels to drive the top and bottom of it's assigned speaker... use the balance control of each to match the top and bottom levels, then the volumes... connect it like this:

Left Speaker Top <=====> Left Amp Left Channel

Left Speaker Bottom <===> Left Amp Right Channel

Right speaker Top <===> Right Amp Left Channel

Right Speaker Bottom <===> Right Amp Right Channel

Once the "balance" of top and bottom is established for each speaker (see the flexibility here?) using the balance controls, set the volumes for the two speakers (see the additional flexibility here?). Seems like this gives you a great deal of freedom to fime tune the sound for the speakers/room system - and enjoy the benefits of biamping, too!

[TBrennan]

Paul----Every active crossover I've seen has adequate controls for adjusting levels. From your description I'm not sure you understand what bi-amping is.

[ben.]

The misconceptions regarding biamping in hifi circles baffles me to no end.

This is how it works. I'll only use one channel with a 1kHz crossover frequency. The second channel would be pretty much the same...

Full range signal (output of preamp, for instance) at line level is sent to crossover (line level or active)

Crossover splits that full range line level signal into two line level signals - one signal (LF) has essentially no content above 1kHz, the other (HF) has no content below 1kHz.

These two signals are sent through individual level controls that can boost or attenuate each signal (LF and HF seperately) in order to compensate for unequal sensitivities of the drivers. Passive speaker level networks do this too, just at speaker level. But we're still at line level here.

The two (LF & HF) line level outputs of the crossover are sent to two seperate amplifier channels. The LF amp is only being sent content below 1kHz and only puts out content below 1kHz. The HF amp is only sent content above 1kHz and only puts out content above 1kHz.

The output of each amplifier channel is then connected directly to the corresponding driver. No passive crossover is used as all that has been done at line level.

Usually the crossover frequency is variable and on many the user is able to delay the LF or HF in relation to the other bands to achieve closer time alignment. This is pretty much all done digitally in pro sound now.

I have a really simple little ART 2-way with a mono sub out that I like to keep around as much for diagnostic listening as anything else. Want to hear what 6kHz and up sounds like from the K400/55 all by itself? Simply unhook the passive networks and dial thing in.

It's kind of a bike riding/tieing shoes thing. Once you get it, you get it...

[jimmy4300]

Lou---It's like this. If you feed one amplifier channel of 85 watts to your speaker you have 85 watts available at any and all frequencies, let's say from 20hz to 20,000hz. You have 85 watts at 20 hz and 85 watts at 20,000.

Now let's say you have a passive crossover at 2000hz and you're feeding each leg (one leg the low pass and one leg the high pass) with a seperate 85 watt channel. You still have only 85 watts available at any given frequency, not 170. That's because only 85 watts is going to above 2000hz and only 85 watts is going to below 2000hz. Just as above you have 85 watts at 20hz and 85 watts at 20,000.

See what I mean?

Yep, I see exactly what you mean. But, if the 2 amps on each side, are only taking care of a limited frequency range, one would think that you would have more headroom (power) in that limited range. I would think that my bass should be stronger, since they are being powered be a different amplifier, and the same with the highs. A Sub has it's own amplifier, and and gets benefit from it. Where am I wrong here? This is all very baffling. (pun intended)

Lou

[Ragamyers]

Lou, This perception that doubling your wattage will double your audio output is stiflingly bogus.

In my limited audio understanding, a two-way speaker, that has 100 watts available to it originally, would use about 12% of that power for the operation of the tweeter and about 88% for the operation of the woofers or potentially 12 watts and 88 watts, respectively.

When you biamp, since you attach one 100 watt amp to the HF and one 100 watt amp to the LF you then have 100 watts available to the tweeter, which does not need a power increase to operate. And you increase power available to the LF/woofers from 88 watts to 100 watts.

So, where you need the added headroom or increased power to the low frequency/ woofers you have now gone from about 88 watts available to 100 available which is about 14%.

This increase to your low frequency power causes an increase in output of about squat.

This is oversimplified and was not intended to be an audiologically sound explanation, but I hope it illustrates to you how biamping with your Denon doesn't double your available power or provide increased headroom where you might want it.

[mas]

While I agree with the main points, I am still going to disagree a bit with a few points... I swear I saw the poor horse move! []<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

Bi- or tri- amping does not by definition make the sound pressure level greater.

But, with regards to headroom and other quality factors, including the repoduction of transients, there can indeed be a substantial benefit - but again, this does not mean that the sound pressure level will be greater!

With a single amplifier channel processing a full range signal, it is expected to do quite a bit. The load spread across the full spectrum being reproduced is complex and various portions of the spectrum can indeed present pressing demands upon an amp - a classic example being extreme transients in bass response. A good example of this is the Dafos drum CD or the cannon in the 1812 Overture on the Telarc recording. (Some folks are Soooo picky! [] )

In such a case, a single amp in a non multi-way configuration (or indeed even a low powered amp in a multi-way configuration driving the bass passband) can be constrained and pushed into its non-linear region of operation - thus resulting in distortion.

In such a scenario, providing dedicated amplifiers with greater capacities focused on reproducing a much more limited passband provides for a greater availability of resources for that passband. Thus transients which place demands upon headroom and other factors can more easily be reproduced without overstepping the total capacity of a unit that must do several complex tasks simultaneously.

You are indeed correct in that the ability to better provide for the headroom/transient provisioning that allows these transients to be reproduced without pushing the amplifier into a non-linear range of operation, is a primary reason for employing a multi-way topology.

But be aware that transients do not significantly change your steady state sound pressure level! Thus you can have much greater transient reproduction and headroom without an assumed increased in average RMS power levels or SPL levels.

OK, now its 'your' turn to pick my explanation apart - just be aware that whatever you guys will claim that I mistated, I meant to say properly ! [][][]

[ben.]

...The load spread across the full spectrum being reproduced is complex and various portions of the spectrum can indeed present pressing demands upon an amp - a classic example being extreme transients in bass response. A good example of this is the Dafos drum CD or the cannon in the 1912 Overture on the Telarc recording...<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

...OK, now its 'your' turn to pick my explanation apart - just be aware that whatever you guys will claim that I mistated, I meant to say properly ! [][][]

It's especially tough as it's 100 years louder than the original...