Bi-Amping  

Do the speakers you intend to bi-amp have two pair of terminals on each speaker - one pair for the low and one pair for the mid/highs?

Welcome!
IMO it isn't worth the effort and extra wire. You can use the search function for lots more on the subject. If you want a technical article: http://sound.westhost.com/bi-amp.htm

OK - just wanted to be sure before making any comments.

Generally, I agree with the previous poster. Most often, it's not really worth doing. However, since you already have the amp/receiver all it costs is a couple y-cables, some time, and some speaker wire.

It's a fairly inexpensive experiment in your case to draw your own conclusion.

Because of my smallish room I choose to not use a typical powered subwoofer and am biamping my Infinity Kappa 600 mains with the help of the Velodyne SMS-1. A Fosgate Audionics FAA 1000.5 5 channel amp powers the center, surrounds, and upper half of the 600s. My choice to power the 10" side mounted woofers is an older Citation 5.1 bridged to two channels. While I have only had this setup installed for 2 weeks and am still experimenting with the SMS-1, it has proved to be invaluable to this setup.
So as to your possible setup a question would be, how do you plan to get the signal to the JVC? Setting the HKs main L+R crossover to small and going with the subout to an input on the JVC should do the trick. But does the 335 eq the low frequency response in its auto room eq program? Also think through and double check all the line level and speaker hookups before powering up and REMOVE the metal straps that connect the crossover at the speaker input. Have fun.

Well, the more I think about it, it might present some challenges to do this.

Since you will be using the speaker level and the pre-outs simultaneously, you will need to use the volume control on the 2nd receiver to balance the levels between the low and the mid/high. Tracking of the speaker level vs the pre-out level could be an issue but it's hard to say if and how much until trying it.

If the second amp was actually an amp and not a receiver then maybe this would even be worth discussing. However, since your second unit is a receiver, then, as whoaru99 pointed out, you would have to level match every time you changed the volume. For example, if you raised the volume on the HK, you'd have to adjust the volume on the JVC to match. Plus, its questionable whether the JVC's amp quality would be comparable to the HK and most certainly they would have a different enough sound that it would be worse in combination.

I'm not sure you would have to change the 2nd receiver volume every time you increased and decreased the H/K volume. If the pre-out and the speaker levels tracked the same then it would be a 1-time match I think.

I'm not sure you would have to change the 2nd receiver volume every time you increased and decreased the H/K volume. If the pre-out and the speaker levels tracked the same (which, on second thought, they really should) then it would be a 1-time match I think.

That's the wrong question... For bi-amping, the speaker terminals should bring
out actual driver connections. These should be driven by the two separate amps,
that are, in turn, fed by an electronic crossover.

Unless specifically designed for bi-amping, speakers that have separate terminals
are meant for bi-wiring (BTW, a totally useless connection, except for the people
that sell speaker wires). These terminals are connected to the input of the internal
passive crossovers, that, in turn, feed the drivers. Useless for bi-amping.

-- Ron

Huh? My Paradigm Studio 100 Owner's manual mentions these two pair of terminals can be used for bi-wiring and or bi-amping.

Regardless if it's the "right" way or not to bi-amp, bi = 2, so two amps = bi-amp in my book.

As I mentioned early in the thread, I agree it's typically not worth doing it this way.

I'm still not totally convinced this form of passive bi-amp is quite as worthless as bi-amp purists indicate - especially if the xover is close to the equal power point. However, if you search my posts you will not find me promoting it.

Bi-amping can make your speakers sound better, if done correctly. Quality speaker manufacturers understand this. That is why they put 2 sets of terminals on their speakers. There is a metal bridge between the "high" side and the "low" side that must be removed in order to bi-wire or to biamp.

Quality electronics manufacturers understand this, because they give you the option to do this with their 7.1 channel receivers. Look in the owners manual of a Marantz or Arcam 7.1 receiver and you will find the necessary instructions.

Channels 6 & 7 on these 7.1 channel receivers can be used 3 different ways: 1) to power speakers 6 & 7 for full 7.1 surround sound. 2) to power a 2nd zone of sound in a separate room. There is a 2nd zone preamp in the receiver so you can listen to 2 separate sources in the 2 separate rooms at the same time, and 3) to bi-amp your speakers.

To bi-amp using a receiver like this, you flip a switch on the back that makes channels 6 & 7 send the exact same signal as channels 1 & 2 to your speakers. Then you use 2 sets of speaker cables to each of your speakers. How can this not sound better? You are doubling the power to each speaker. Why do you think that people want bigger and more powerful amps? More power! What happens when you move from a 4 cylinder car to a 6 cylinder and then to a big V-8? You get more snap, more punch, more power. The same thing applies to electronics. That is why manufacturers offer different powered receivers or amps in their product lineup - 50W, 100W, or 150w.

Manufacturers of High-End stereo preamps have been doing the same thing for years. They put 2 sets of pre-outs on their preamps to drive 2 stereo amps. More power.

But the correct way to biamp is to use a pair of the identical amps, not 2 different sized or brand amps. You want the sonic signature of each amp to be the same. Think about it. When you are shopping for a new receiver or amp, you listen to as many different brands as possible. You are looking for the amp that sounds the "best". You wouldn"t put together the "best" amp with the "2nd best" amp to bi-amp. They sound different from each other and may not work well together for various reasons, ie. impedence, current etc.

You should also consider using the same pairs of speaker cable to the "high" side and the "low" side for the same reason. You may not think that different speaker cables sound different from each other, but common sense suggests that they do.

You are inferring their motives from your observation. I have spoken with some manufacturers who offer 2 sets of terminals because a significant portion of the market demands it and not because they think it is useful. Adding the extra terminals is inexpensive and it insures that those who believe in bi-wiring/bi-amping are not excluded from their marketing and provides an additional revenue stream for their dealers.

Besides, why do some "quality speaker manufacturers" not do it?

Just another perspective on "why."

Kal

Actually there are a lot of bi-amping fans, that would strongly disagree with that. And that they even mix solid state amps with tube amps when bi-amping, just for those reasons that you say are bad.

LOL!!!! Yeah right......

That is definitely not what common sense suggests.......
Nor can it even be proven that they do!

It is suggested that the 'lows' side be taken up with thicker gauge cables.

Anyway, if you have two identical amps why not just bi-wire them using y-connector rca's and use them as monoblocks?

I biwired my KEF Reference 207 using the spare amps i had left on my Denon AVR 5805. For low-range I used Monster Cable and an unbranded thin wire for the Mid/Hi Range. I decided to disconnect the biwiring and use the Monster Cable instead for all freq. When I turned on the system, I couldn't believe the difference, the Mid/Hi had opened up so well, I'm not good at describing sounds but it was just more rich and didn't sound suppressed. My $0.02.

There are many manufacturers who add features for marketing reasons, and there are quality manufacturers who do not provide the option to bi-amp or bi-wire.

But there are many manufacturers who not only provide the opportunity to bi-wire or bi-amp, but actually encourage owners of their brand of speakers to do so.

Linn is a respected brand which does.

You can read Linn's reasoning for bi-amping, tri-amping & making their speakers "Active" in this FAQ:

http://www.linn.co.uk/faqs_loudspeakers.php

Linn gives you the option of taking their speakers to an even higher level of performance. You can make their speakers "Active". To do that, you remove or bypass the passive crossover in each of the speakers. You use one stereo amplifier to drive each"way" of the speaker. ie. "2-way" speakers require 2 stereo amps, "3-way" speakers require 3 stereo amps. You then install "Active crossover" cards in each of the amps. Crossover is then done at line level instead of speaker level. The performance difference is dramatic. :)

I have a fairly decent understanding of analog theories (pretty decent EE background), and have recently read so much about biamping that is contradictory and or contentious that my previous innocent (and admittedly over simplistic) motivation to try it has all but fizzled.
I consider the best technical and empirical source of information I've found thus far to be in the two part article found at:
sound-dot-westhost-dot-com-slash-bi-amp-dot-u r l.
...however, I can't seem to get past two issues that I just can not reconcile:
(here goes...)
1) It would seem to me that passive biamping (poo-poo'd by real biampers) would yield significant (and not marginal) gains in power due to a factor largely undiscussed: Current.
I can make the current overload leds on my Parasound 855A flicker fairly easily at high volumes driving bi-wired Klipsch RF3s. Picking up another 855A would give me biamp capability for my front 3 with 2 leftover for zone 2, and the cost is managable.
My theoretical understanding says that even with Y cables and the speaker internal passive crossovers untouched the impedance the amplifier sees changes fairly dramatically
when two 85W power amp channels have effectively split the combined signal losses of the passive crossover. Am I missing something?
This is actually stated (or at least implied) by one speaker manufacturer (KEF?) in some tech tip reading I found somewhere on the web.
So if my amp can supply 30 amps per channel, I have this picture of (current setup) the passive crossover in the speaker throwing away some watts in signal losses that convert to heat in the high pass filter, and then some more watts in the low pass filter.
Would not each of the two seperate amp channels see just one of these loss components when biamping?
Confusion point number 2 is:
Getting back to current, OK, I can see how biamping with a line level electronic crossover will, for instance, remove the 1K signal that rides on top of the 100hz signal, thereby allowing the full voltage range of the amp to be used by the 100hz sine wave before clipping (which I can see is a tremendous advantage); But is it not common to run out of current prior to clipping, depending of course on impedence?
And that ties back to:
What happens to impedence when you split the speakers passive crossover?
It seems this has to be at the heart of whatever the passive biamping advantage would be.
I would love to keep this discussion positive, some threads on biamping are not very useful for us folks just trying to answer the question, "Would biamping work wonders for me?".

AFAIK the Linns are unique. Not only have they designed an active crossover specifically for the speaker, but the speakers internal crossover senses when it receives a filtered signal and bypasses itself. (at least that is how I read thier literature)

Let's not start mucking up this discussion. The argument is on PASSIVE bi-amping. If you switch it to active bi-amping I feel that a lot more people would agree that that is more beneficial. I know every major feature film mixing facility in Hollywood uses active bi/tri-amping on their stages. Anyone who has a 5.1, 6.1 or 7.1 system is in some way using active bi-amping are they not? Your sub is most likely on a different amp than your mains and is powered post-crossover. I think the need for multiple amps on 7" drivers (and smaller) in a passive crossover situation is negligible.

As far as using two different kinds of amps I feel that we should agree that it can be done with good results but it takes a lot more experience and trial and error to get it right.

Arguing with people who believe that more expensive wires are better than cheap wires of equal guage is like trying to argue with religeous people about whether god exists. You can't refute someone's belief if that person refuses to use science as a form of evidence.

Theseeker,

There is no way I can improve on Rod Elloitt's excellent tutorial, and I think you have a solid understanding of the issues.

We all like to focus on the power output of amps, but that is a derived number. What we actually measure is the output voltage across a known impedance (resistance). Solid state amps are voltage amplifiers, which is to say they receive an incoming voltage and output a higher voltage at the speaker terminals. The maximum voltage is the amplifier's power supply rail voltage.

Speakers are voltage sensitive devices. If you were to take and individual driver and put a 9 volt battery across its terminals the cone would move in one direction, say 3mm. If you were to replace with a 12 volt battery it would again move in one direction, say 4mm. Putting a second battery in parallel with the first would not increase the voltage and therefore not increase the excursion of the cone. Similarly, putting a second amp in parallel with the first does not increase the voltage to the speaker.

Normally speaker crossovers are (in the case of a 2 way) a combination of 2 filters connected by a jumper; a high pass filter for the tweeter and a low pass for the midwoofer. The crossover has been designed to level match the 2 drivers such that a 1 volt input at 2500Hz puts out the same volume from the tweeter as a 1 volt input at 1000Hz from the midwoofer.

Now let’s say we have an amp capable of outputting 30 volts (rail voltage). As the woofer circuit is in parallel with the tweeter circuit, each receives 30 volts at each of their terminals. In the case of parallel bi-amping, we now have two amps each capable of providing 30 volts to the speaker terminals one to the woofer and one to the tweeter BUT it is still just 30 volts and the output will be the same.

Now here is the caveat, and the only case I can see for parallel bi-amping.

Speakers are reactive devices and at certain frequencies the impedance drops. As this happens the amplifier must provide more current. If the amp can’t provide enough current, the rail voltage drops, providing less available voltage to the speakers. This usually happens at midwoofer frequencies. Let’s say in our example that our 30 volt amp can now only provide 25 volts. This will potentially cause clipping for both the tweeter and midwoofer. If we are parallel bi-amping the midwoofer will see only 25 volts and clip, but the tweeter will have 30 volts and may not clip.

Any questions?

ericgl -

Thanks. This is the exactly kind of dialog I was hoping for.
I agree with your point about speakers being primarily voltage devices, and with your point (If I understood correctly) that the pivotal issue is the rail voltage dropping because the current demand exceeds the amps current supply capability.

Your last point is key:

"If we are parallel bi-amping, the midwoofer will see only 25 volts and clip, but the tweeter will have 30 volts and may not clip."

I agree. My understanding is that this is due to the more strenuous demands of the midwoofer as compared to the demands of the tweeter (I think Rod Elloitt talks about this). I believe Rod says that midwoofers operating at typical frequencies demand more power (due to lower impedences under some circumstances perhaps?) to operate at a given SPL than tweeters do at typical frequencies at the same SPL.

So now the only question I am left with is this:

If the current demand exceeding what the amp has available (at certain frequencies because the impedence drops) is responsible for dropping the rail voltage and causing the midwoofer to start clipping, wouldn't off-loading the current demand of the tweeter (and the additional current lost in the form of wattage dissipated in the high freq sub-portion of the passive crossover) provide the equivalent amount of additional current reserve for the midwoofer, and thus in a biamped system prevent clipping until quite a bit higher speaker DB level?

Also, out of curiosity,
Does anyone reading this know where I might find specs or information on impedences for each side of a (disconnected) passive crossover when the two halves are disconnected (I have Klipsch RF3s)?
Wouldn't this provide a rough measure of the quantitative improvement to be had from passive biamping, again, unless I've misunderstood something...?
Certainly, if the impedence stays at 8ohms for each half (though I don't know how since impedences in parallel essentially divide), that would crystalize for me why there's no gain from passive biamping...

Thanks in advance for any clarification or info you have to offer.
-TheSeeker61

Solid state speakers is a typo, I need to re-read my posts b4 posting!

bi-amping by using the back surround channels on a receiver is pretty much worthless...you are still using the same power supply...it does NOT make it 100wpc to 200wpc..

Krabby5 -

Agreed.
Reasons for this:
Receiver power supplies are typically wimpy compared to a good power amp where there are individual windings on the transformer for each amplified channel.
With a typical receiver, when the current supply capability exhausts for an individual channel it will likely reduce the current available to the other channels as well, so having a second channel for some backup juice affords little if any improvement.

Ericgl -

I re-read Rod Elliotts article and also did some other reading and I believe I now understand why he says passive biamping is not worth the money, and why others who are knowledgable describe any gains as "marginal":

I have been focused on current capability exhaustion, but I am now convinced that this doesn't happen - especially with a quality power amp - until the voltage is approaching the limit (rail).
(And even then, perhaps ONLY if there is some condition which reduces speaker impedences)

So lets say for example that on a certain sound track passage being listened to at a high volume the speaker impedences drop and the power supply runs out of current when the voltage is 95% of the max V:

Even having an entire extra amplifier channel dedicated will merely allow the missing 5% of current required to get to the rail, and of course the key is, it won't increase the rail voltage at all!

I'm going to buy some crossovers modules from Marchand and build myself a line level crossover. I'm doublful that I will modify my speakers - I have plans to eventually upgrade from RF3s to RF7s, which is partly why I wanted to set up a biamped system to begin with (RF7s will handle 250 watts and my power amp puts out 85 watts per chan).

TheSeeker61, 10-4, over and out.

Thank you for taking the time and effort and keeping an inquiring mind. So many don't.

I have a Marchand X-O and it is a great piece, but it doesn't allow for changing frequencies or slopes on the fly. I am considering a Behringer DCX2496 for my next DIY speakers.

If your RF3s have a terminal cup, it may be pretty easy to bypass the crossover.

that is very rarely the case.

tlf9999 -

I would at least partially agree: I think it's VERY rare in the receiver world, But I'm not so sure if it is rare in the Power Amplifier world: I know that most or all of the Parasound power amps have seperate windings (try googling "parasound hca windings").

This is one big reason why receivers and amps APPEAR to be rated the same but often are not:

What I'm about to say is based on folklore more than any factual reference I can quote, but I have heard many times that the good power amp companies rate their amps in Watt Per Channel With with All Channels Driven - that is, driven simultaneously. I do not believe that many of the receiver companies determine their Wattage ratings this way. This is why my 85 Watt Per Chan Parasound amp (power-wise) is essentially equivalent to my Denon 3803 receiver, even though the 3803 is "rated" at 110 watts per channel...

even in the power amp world, it is quite rare to have separate windings for each channel: as it doesn't really offer much advantage over the conventional psu topology.

More likely you will see monoblocks or shared psu among 2/3 channels.