Kpinneo.. would love to hear how these turned out.
"Polyamping" A Look to the Future or Fancy Fad?
In a recent quest for information regarding DIY speaker designs, I was referred to the Linkwitz Orion Project. These speakers employ active crossovers and it is suggested to give each driver its own, separate amplification (actually one for each woofer and one for the tweet/mid - three per speaker). Linkwitz recommends the ATI AT6012, a twelve channel, six zone amp (60W/ch). I am not sure about the merits of the ATI amp but, regardless of amp, does anyone think this will be a "growing" design. I mean I have heard the benefits of biamping and have heard tell of triamping but, in this case, "sextamping"? Octamping would seem to be next. All accounts say that the Orions sound fabulous. Perhaps I am just behind the curve. What so you learned folks think of this direction in audio?
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Gregm, Here's how I'm isolating midranges: 1. The Seas midranges will be magnet-mounted as Linkwitz' revision would do, but with my own custom parts.I have used a piece of 4" ABS coupler (4 1/2" ID)about 4" long, mounted the magnet just inside one end of theABS (glued) with a small air gap. Then the mounting puck I inserted in the other end, just protruding, set in a bed of black silicon(filling the entire space inside the ABS), so the driver is only connected to the puck by a bed of silicon. 2. The mounting frame will be triangular in shape and sturdier than Linkwitz' design. 3. At the mounting surface at the top of the woofer baffle box, I am adding two layers of 3/4 -inch ply with shear damping inbetween the layers- microsorb , probably. 4. The mounting frame will actually be attached to a commercial damping platform which will sit on top or be attached to the baffle box. 5.The entire inside/ rear surfaces of the speaker will be covered wiyh microsorb or similar and D-flex panels. 6. Tekna-sonic vibration dampers will be attached near the woofers. Hope this answers your question. As an aside, I've changed my amp selection. Decided to use a McIntosh MC275 to drive the mids, and The ATI6012 for the other 6 channels. Since the Mac has input control, and the ATI has individual controls, I'm hoping the integration won't be an issue. |
Gregm, In answer to your question, I'm attempting to isolate the midrange as much as possible from the baffle resonance created by the woofers at high volume levels. That is the only complaint I've seen about the Orions. By all accounts, the more that the midranges are separated from baffle resonance, the better they sound. This is one area I think Linkwitz could have done a better job in design. See my next post for my plan of attack. |
Hi all, glad to read all your inputs, especially as it relates to my current project. I'm building the Orions, but am making what I consider to be significant improvements to Linkwitz' design. I do highly regard his designs and expertise, yet in researching the Orions for this project, it became clear to me that some improvement could be made in the area of baffle resonance, for example, and so I am taking great pains to isolate the Seas midrange and also dampen overall resonance. My system will be: Sony SCD-1 modded Supratek Sauvignon linestage Linkwitz designed active crossover (2) Bel Canto EVO4 II (each driver driven by 120w) Linkwitz Labs Orion Speakers Chimera Labs CCC Litz-wound interconnects and speaker I can hardly wait to see how this sounds. I won't be done with everything until May or so. I'll post with an update if anyone is interested. |
Linkwitz doesn't require that you run the ATI amp to drive his Orion loudspeaker system. What he requires is that you use 8 identical channels of amplification. His bass drivers are mounted on an open baffle, so they can't handle a lot of power. 60 watts per driver is about it. And you certainly don't need to use more than that for a tweeter! I'm planning to build a pair of the Orions and have cheaped out by picking up 4 Hafler P1000, pro-style amps. They're 50 wpc and are 1U high rackmount pancakes. I've gone to an all rackmounted system and these things mount in there with plenty of room. I picked 'em up on EBay for an average of about $140 each, so for a bit less than $600 got the amplification I need. Russ |
I too haven't had the time to read this entire thread but have been thoroughly enjoying the Orions for several months with the recommended ATI amp. My comparisons with more conventional speakers and amps would be the Verity Parcifal Encores, Maggie 3.6s, and Talon Khoruses (old version), (though I've heard most speakers in the $5,000 to $16,000 range) driven by Edge NL 12 amplification as well as Essense amps. In my opinion, I have gotten more musical pleasure out of my Orions/ATI combo than any other system I've had and i have in no way felt the ATI amp inadequate even when compared to my prior amp which was $15,500. Spend more if you'd like but this combo is pure musical enjoyment. |
Having not read what the others have already stated, (sorry but I do not have the time), I will flat out state that the Orions, even driven by the ATI amps and entry level electronics, are among the best speakers in the world today. I was lucky enough to audition them in Sigfried's house and hear the magic first hand. I have worked within the high-end industry for the past 6 years, attended several CES shows, and heard several outstanding systems, including my own which retails for way to much money. Without a doubt, Sigfried's modest setup, in terms of ultra performance systems, is among the best of the best despite price. Active speakers require several channels of amplification, cables, etc, but is truly the best way to achieve realistic sound. |
To get an idea of the power demands of driving a woofer to realistic levels, get an amp that has power meters. Forgetting whether or not they have a high degree of absolute accuracy, just put on a disc with a well developed bass line and crank it up some. You will see the meters barely move, until the bass line kicks in, then if the meters have a quick rise and decay, you can pretty much track the rythym with the meters, showing 10-100x more power requirement than the highs. I first saw this on a CM Labs 150 wpc amp I owned in the late 70s. Never had another amp w/meters, but it sure taught me the power required for accurate bass. |
Well I made up the label "polyamping" for the purpose of this thread title though, like you say, there is nothing new under the sun so I won't claim it as an original idea. Nor will I claim, or even remotely infer, that I "invented the whole thing". Had I the technical expertise to do so or the stones to claim such, I wouldn't be here asking questions. Has anyone taken a look at the Orions under the link http:\\www.linkwitzlab.com who would like to comment on whether it seems a reasonable approach? |
On paper the idea makes alot of sense with the primary benefit coming from the use of an external active crossover network. However, with all things audio related, there is not a single path to better sound reproduction and polyamping has its own set of trade-offs with cost and system complexity being the most obvious. |
If you mean by "a look into the future" that amps will be manufactured in mult-two-channel construction, then I would disagree with it being a trend - too expensive for mass consumption. One if the caveats of mult-amping is that all amps have the identical gain (or withing 0.5%), which basically means using identical amps. If the price of two-chanel or mono amps goes up exponentionally with sound quality, then the prices will climb (linearly??) for each set of channels. In this regard, I agree with it being one of diminishing returns, and with the price of top notch amplification up in the stratosphere, the question is: when does, for example, multiple Brand X mono pairs equal the performance of a one pair Brand Y. An interesting calculus problem. |
Mezmo: While i appreciate the vote of confidence, don't encourage me. I already open my mouth too much as it is. Just ask Brulee.... 4Yanx: What is good for the goose is not always good for the gander i.e. personal preference rules. Once you've heard "commanding" bass with impact, definition, authority AND control, you'll know where Greg and others like us come from. You might be amazed at how much power high amplitude reproduction of low frequencies actually takes to do "right". This is especially true if you have low efficiency speakers. To try and explain this simply, the more excursion that a driver has to make, the greater the distortion and the poorer the transient response. As such, using multiple drivers allows one to move as much air without any individual driver ever having to make much of an excursion. They are all sharing the load rather than having to deal with the physical / electrical demands individually. This is the approach that Dr Bose took with the original 901's and Bill Duddleston likes to promote in the literature of Legacy products. While such an approach is very valid, you now run into problems with impedances and high levels of reflected EMF*. As far as dealing with low impedances and higher levels of reflected EMF, it takes "muscle" to deliver the power required to control all of the drivers and deal with the reflected EMF. Bob Carver does a good job of explaining this in the white papers of his Sunfire subs and i encourage those interested in learning about such things to give those a read. He tries to keep things simple yet get the point across. You don't have to like the product to understad that there is a a lot of valid research behind it. As is so often the case, the good intentions and valid research get lost somewhere along the production lines. To those that that think that "high power" is unnecessary, i'll use the same analogy that i use at work all the time. If you've been walking all of your life with no other means of travel, a bicycle seems great. When you start driving a Yugo, the Yugo makes the bicycle seem antiquated and slow. When you start driving Lincoln's, Cadillac's, Mercede's, BMW, Porsche, Ferrari, etc... everything else prior to that point seems like a joke. You look back and wonder why it took you so long to understand your current vantage point and realize how much better it could have been and / or how much you've missed along the way. While we call this "the learning curve", it is all a matter of perspective, experience and personal preference. As such, "good" results to Billy Bob might be "piss poor & pathetic" to Ray-Ray : ) Sean > *This is not to mention a slew of other problems that are related with acoustics / room loading, but that is a whole 'nother ball of wax. PS... i was able to mention Bose, Legacy and Carver all in the same post in a positive manner. That must be a first for Audiogon : ) |
Some interesting comments. Bob, I was not singling out that an ATI amp be used, just that such was sugeested in the design by the designer. I have no knowledge of these amps personally. It was the only design in the DIY realm that I saw which incorporated use of a mutli-channel amp. Sean and Gregm, your comments with respect to sufficient power are intriguing. How would the 60w not be enough for quality bass response when others claim to get such even with very low wattage amps? I am not saying you're wrong, just asking because I don't know. Sorry if I overlooked designs of the past that used this design scheme. It was the first I've come across that really went beyond biamping in what seemed to me a radical way. But then, I haven't been auditioning dozens of speaker designs over dozens of years. Because Linkwitz is considered to be rather an innovator, I wondered if his design might be a direction for the future. If such has been done before, though, it wouldn't be the first notion of a technology or approach in audio that was relagated to "dinosaur" status, only to raise its head triumphantly at some point in the future. I'd say analog front ends are an example that many here are familiar with. |
At present I am having a set of modified NEARs built using an outboard active XO.It was suggested to me months ago and it is the last frontier for getting all you can out of the amps.More efficient to use dedicated amps for the drivers. It just makes plain sense to me.It also gives you the dexterity to set the seakers to room variations.That in itself makes it a useful.You can trim the ranges in order to get the drivers to blend better with the room dimensions and accoustics. JMO |
Actively driving the speaker with one amp per driver, is the oldest method of electronic sound reproduction known. It started with the earliest sound systems with mono amp and single driver speaker. As such, it can hardly be considered either a "look to the future" or "fancy fad". However it can be considered a valid method of sound reproduction, that eliminates some of the problems associated with the "newer" multi-way designs, especially passive crossovers. In a single-driver system such as mine, the driver is "actively" or "directly" driven because there is no passive crossover. In multi-way systems that are multi-amped, they are "actively" driven for each driver, and again there is no passive crossover. While I agree with many of the statements made by other posters above, I feel that elimination of the passive crossover is the strongest reason for active multi-amping. |
Experience leads me to second Sean's note about power hungry lower frequencies. In my much lesser system than Sean's, the ~85-22Hz area (8"x8 woofers) are powered by ~500-600W at the nominal impedance rating -- and not quite adequately so, IMO. I'm bi-amping, BTW, and thoroughly recommend multiamp configs... |
I think that such an idea is great. Having said that, i would emphatically state that 60 wpc is not enough power to achieve quality reproduction of low frequencies in my opinion based on quite a bit of experience in this area. With that in mind, i've done something very similar but gone to an extreme in the method that i chose. To try to sum things up briefly, i am actively tri-amping with six stereo amplifiers. The amps are set up to operate in what is effectively a monoblock format even though all 12 channels are in use. While i did so for multiple reasons, my primary goals were to increase dynamic headroom, achieve the ultimate in stereo separation and to spread out what is a very tough i.e very reactive AND very low impedance speaker load over multiple amplifier channels. With the average impedance of the system hovering around 2 - 3 ohms per amplifer channel, i've got 2400+ wpc ( using the various amplifiers 4 ohm power ratings ) as things are currently arranged. I would realistically rate output capacity as somewhere around 3 KW rms per channel at the actual impedances that the amps see. Using this approach, none of the individual amplifier channels are "pushed" as hard as they would be if i had them set up in a more conventional manner. On top of this, damping factor is doubled and there is no chance of ever clipping. While the amplification system has worked most excellently once i was able to get things dialed in, i just need to find a way to quit demolishing specific sections of the speakers. I've still got a ways to go on this, but it's pretty much been both a "labour of love" and a learning experience at the same time : ) Sean > |
while I am DEFINITELY an advocate of speaker manufacutes offereing ACTIVE multi amp designs for speakers, I must say it's going to have to be realtively intuitive and straight foreward for it to be so successful I think! DIY kits will have limited application of course. While the mass market really needs this as a step towards the future I think, if we are going to see any real sonic steps ahead in overall speaker performance! I've long time said that the average PASSIVE speaker design that is common place out there, has basically seen most of it's limits I think! I mean unless we can come up with practical driver designs that are WAY MORE EFFICIENT AND SENSITIVE for increased dyamic transparancy and potential throughout the frequency spectrum, ACTIVE speakers are really the only way to move towards for improvments where Ithink speaker designs need to go! I mean, we pretty much have the ultra transparant, ultra detailed, ultra un-colored beautifully-soundstaging-thing down with speaker designs at the very best as it is now! Most high end speakers, I find, usually fail in ultimate terms in respect to dynamic transparancy. Active design speakers(even speakers with powered woofers) and ultra high sensitivity speaker designs have a HUGE advantage in this area, due to an efficiency and or sensitivity advantage. I mean, if we doubt that the main area that needs to be improved on with speaker designs on the whole is dynamic efficiency, just ask yourself why someone like J Gordon Holt of STereophile mag claimed that the Active ATC speaker system at $90k "might be the best speaker system in the world" right now, and that "he's not heard better!"...? So let's face it, ultra high efficiency/sensitivity active speakers, horn speakers, and powered speakers can do what others can't in the dynamics relm. "multi-amping" actively is most definitely going to help solve some dyanamics issues if done right. But then again I think history has proven that simpler sells better, and is less likely to dis-suade people from investing in something so complicated and demanding technically! If speaker manufacturers would more and more go down the road, at least offering more high end speaker designs with active self-powered woofers incorporated, things would improve dynamically for the masses. While I do see some of the so called "hi-end" speaker people out there doing the "active-thing", and even the powered woofer thing, I think there's a greater need for more and better designs from more manufactureres! It also needs to remain simple and practical from a number of standpoints for the consumer I think...even for the audiophile tweek!(whose likely to steer towards speakers that can accommodate their favorite matching gear and such. Still, there's no doubt that "multi-amp" applications have their places, and since systems keep getting more complicated and involved with multi channel now-a-days, I can see that multi amping would have applications than ever to expand too. I do doubt however that most people want to get involved with so many amps and wires and connections and such. I think it's definitely better if you can put the amps in/on the speaker enclosures themselves. This alone makes for a simple marriage of digital active powered sub and woofer designs, and leaving the amp for the mid/tweeter up to the consumers discression. There's always compromise I suppose. If they can keep it simple, practical, effective, modestly priced, and sounding fantastic, I think multi-amped speakers would have a future on a larger scale. I hope so... |
