Anybody true bi-amping their HT???

Discussion in 'AV Receivers' started by John S, Feb 9, 2005.

  1. John S

    John S Producer

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    From the pro audio world, Bi-amping / Tri-amping was always the way to go by the largest of margins.

    I'm thinking 14 power amps here and 7 channels of electronic cross over.

    Probably using two AVR's to provide all the power amps needed. Denon 4802 and a Pioneer 1014/1015 to achieve this somewhat crazy idea.

    Any suggested electronic cross over products multi-channel or otherwise?

    Any suggestions on where to cross from my low end 8" drivers to my mids/highs??? JBL S38's are the speakers.


    Thanks as always in advance.
     
  2. John Garcia

    John Garcia Executive Producer

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    I have yet to see anyone who has done a true active bi-amp setup, and I've been doing this stuff for over 12 years.

    I don't really see any reason to bi-amp surrounds. It just wouldn't be necessary, IMO. How about starting with just the mains or front three to see if it is even worth the effort?

    One thing to consider also is that there are certain things like driver phase/alignment WRT each other, as well as specific characteristics that the individual components of the x-over bring to the picture that may not be simple to reproduce with active x-overs.
     
  3. John S

    John S Producer

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    I guess we will see... I should be competent enough to re-engineer the cross over section. I should be able to post back in April on my findings with it all. The potential performance gains are to high for me not to try it. I'll bank if I get it going, it will be better than separates not bi-amp'd. But just as you said it remains to be seen.

    The price of a Pioneer 1014 is low enough to give it a try anyways. I would probably put the mid/highs on the Denon amps. Except for the cross overs, all channels are nearly as easy to try as just the fronts. I'd be afraid the gain staging just wouldn't be right only doing the fronts too.

    I like the fact that you have never seen it done, would make me unique if nothing else. [​IMG]
     
  4. John Garcia

    John Garcia Executive Producer

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    Well, I've never seen it done, but I also tend to work on the average joe systems, not the high dollar guys, which is where you would be more likely to see this sort of thing. [​IMG]

    What speakers?
     
  5. John S

    John S Producer

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    JBL S38's......

    I'm pretty game for it at this point.... I have some 1/4 electronic crossovers left over from the band / audio engineering days too, but would rather have something RCA gear'd more for this application. But I can go down and pick up used stereo cross overs several places cheap around here at musician type stores.
     
  6. Wayne A. Pflughaupt

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    What kind of gear, John? Personally I’d avoid any low end pro brands like DOD, Phonic and the like. I’d even stay away from Behringer for anything full-range; however, a lot of people seem to be happy with their experiments with the DCX2496 crossover/processor.

    As far as electronic crossovers with RCA’s, that’s a pretty rare thing. You might look into high-end car audio for that; it wouldn’t be hard to adapt them electrically – a decent a/c adapter would probably do the trick - and a lot of that stuff has excellent specs and sonics.

    Regards,
    Wayne A. Pflughaupt
     
  7. Mike D.

    Mike D. Stunt Coordinator

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    Just curious about this... The S-38's don't have 2 sets of binding posts. How will you connect both amps to the speakers? I could be totally off base here, if so please pardon my ignorance... I have the S-38's in my second HT/game room, great speakers for the price...
     
  8. John S

    John S Producer

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    Well being an electronics type from way back... 1982 degree in Communication Electronics, I am confident I will have no problems re-engineering the cross overs in the speakers. The bass driver is easy, no cross over, the mid to tweet can be as simple as a cap, but I would have to do some phase testing on it to make sure. I will do what is needed to make it right though.

    So basically, I am going to hack up my quite pretty s38's!! [​IMG]

    It will be interesting to see how it all turns out. I get more commited to the project everyday for sure.
     
  9. Elinor

    Elinor Supporting Actor

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    Why not just buy better equipment?
     
  10. John S

    John S Producer

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    Because I know the the bi-amp will surpass the "better equipment, unless it is also bi-amp'd.

    My equipment is more than fine the way it is too. This is sort of an experiment, that I am pretty sure will pay off, for the small amount it will take to try it out.

    Pretty lame-o post by way the Elinor to say the least. I mean your not even a little bit curious as to how it will perform? Ever done pro-audio bi-amp / tri-amp -vs- single amp with passive cross over? Any serious audio and/or HT enthusiast with such experience would almost have to be more than a little curious about it.
     
  11. Elinor

    Elinor Supporting Actor

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    Well thanks John. That's a really nice way to start the day. That earns you a space on my "ignore" list.

    Personally from all that I have read the "rewards" of biwiring, biamping, etc. are highly debatable. Can you point to an A/B study by an objective reviewer that has established a benefit to doing it? I don't recall ever seeing one.

    But by all means, do it.

    Sorry I wasted your time with a lame-o post. Don't bother replying, I won't see it, unless you wish to make some point for the other readers.
     
  12. John S

    John S Producer

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    Bi-wire, it is agree'd, limited for sure at best. But true bi-amping, the benefits are more than quantifiable.

    I'd say I only answered your post in a similar manner as your post to me on the subject. Bi-wire is a gimmick in my opinion.

    And I suppose my additional post was for those interested in the concept for sure.
     
  13. Wayne A. Pflughaupt

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    Mike,
    John is talking about active bi-amping, where the passive crossovers are bypassed. An electronic crossover is used to divide the frequencies. Obviously a speaker has to be modified to accept a direct voice coil connection to each driver in the speaker.

    John, I think Elinor was just curious, not trying to be rude.

    Elinor to answer your question, it’s pretty well established that active bi-amping (not to be confused with more common passive bi-amping) can deliver significant improvements. Much of the benefit comes from unloading all those passive components from the drivers that can affect their voicing and performance.

    For instance, many years ago I did a slight mod to the crossover in my mains, raising the crossover frequency from 1200 to 1800 Hz. I was surprised to hear a change in the way the bass sounded.

    One of our Forum members Michael R. Price has been experimenting with bi-amping an Adire 281 kit, with remarkable results. You can read about his experiences at this thread from Home Theater Talk:

    http://hometheatertalk.com/httalk/viewtopic.php?t=7824

    Regards,
    Wayne A. Pflughaupt
     
  14. John S

    John S Producer

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    I agree, I probably took the post the wrong way most likely.

    I am sorry for that if it is the case. Hard to say still how the post was meant. Seemed dismissive and a little condensending, I tried to post back at the same self percieved level. I didn't think either post was really all that harsh though Elinor's nor mine.

    I can say, I am darn excited to try it out for sure.
    And thanks for the excellent post about somebody else that is doing it.
     
  15. andreasVenter

    andreasVenter Auditioning

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    Wow! This sounds really exciting!

    I do have two HT receivers, should I also try? Naw, I know to little about active crossovers, etc and besides a soldering iron becomes a dangerous weapon in my hands!

    I suppose the answer to the question "Why do it?" would simply be "To see if it could be done, and having fun doing it"

    Do keep us posted on your progress!
     
  16. Vince Maskeeper

    Vince Maskeeper Producer

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    Jon,

    I am one of your guys: I have tried it, in two different configurations:

    I started out with an active 2 way setup: Instead of using the receiver x-over, I used a set of BSS crossovers to active split the main front 3 channels into sub/main signal: the main speakers were still passive 2 way in the original configuration. I used Ashly amplifiers (FTX 1501s on mains and 2001 bridged on sub).

    Later, I played around with 3 way for the fronts, using an Omnidrive and removing the passive crossovers on the mains- and then switching to a biamped pro speaker (Some community boxes). Again used Ashly for amps.


    Bottomline? I felt it was a waste of time.

    Despite also spending the majority of my life as a pro guy- I really found the audio "improvement" to be negligable...

    The appeal of an active crossover system, imho, is simply a matter of flexibility. Having an active variable crossover in a system is not only desirable in terms of adjusting a system to different room conditions (a key element in the realm of mobile PA systems)-- but equally important is the ability to adjust and adapt to different equipment. Since making money in the live audio game is really a matter of being able to apply the best configuration for the needs at hand, having the most mix-and-match configurations is also a key.

    To be honest, none of these issues really come into play in the HT environment- so the appeal is greatly reduced. NOt to say that additional control can't yield better results: in most cases the improvement I was able to attain was usually the result of boosting the tweeter/horn driver individually for soundtracks that were muddy.

    Changing the load by taking the passive x-over out of the chain certainly changed the way the speakers sounded, and allowed me to experiment with the crossover point, in the end I settled on a slope that was remarkably similar to the stock passive crossover. The speakers sounded different, although better was debatable. I've found, in the power levels used for HT applications driving good quality speakers simply aren't enough to make the passive electronics limitations a real shortcoming.

    I think if you're going to go with sep elements, I would say your most useful configuration would involve a good parametric EQ in each signal path and sticking with speakers known to have good passive crossovers. IMHO, this would be more useful and more effective than running 6-8 channels of active crossover.

    Oh, i would say with one exception, if you're ht room was more theater sized, for example if it seated more than 100 people, i would then say I might find calibration and configuration a bit easier with active crossover systems. But, in my case, i played around for a few months and went with a preamp, eq, amplifier signal chain running into standard paradigm passive speakers.

    Most of the guys I've read who have been super excited about the change seemed to simply be excited that it was "different" - although, again, it's tough to declare "better." I really think for the effort and expense of adding 7 channels of 3 way crossovers, there are a ton of other ways your system can be improved.

    my 2 pennies.

    -Vince
     
  17. Michael R Price

    Michael R Price Screenwriter

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    Active crossovers can sound a lot better, but you might be surprised at how much work it is to make them sound better than the passive crossovers in your speakers. For the JBL's, I'd say it might not be worth the time and money.
     
  18. John S

    John S Producer

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    Hmm, I did decide to leave the current cross overs in tact just in case I didn't like it, I actually pulled one of the passive crossovers last night. I found some rather off name stereo cross overs at my pro audio store yesterday after work, that actually had 1/4" and RCA's and get this included a parametric EQ for each channel as well. I didn't buy them, but I think I am going to, just need to go back during the day so I can haggle with the owner for a quantity/old large customer discount. The were marked at $199 each.. Something like Ediserol or something like that. They told me they were a division of Alesis. I can probably get him to do his cost on them as we go way back, lots of dollars done bewteen us in the past.

    Some other benefits to attempting this are the fact, the Pioneer as more bells and whistles on the pre/pro, so I will gain some additional functionality, even if in the end, I just run it into my Denon amps. The only reason this has come up, is because that dang Pioneer 1014 is so cheap for all you get with it.

    But if I get these guys, I will at a min have per channel EQ, so not a complete loss.
     
  19. John S

    John S Producer

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    PS: I am only going to go two way active here. Tri-amp can drive you crazy with off phase error and stuff. Well, I got a nice powered sub too, so I guess technically I am tri-amping, but not to the speakers.

    I do have some concern about it all, I mean what I love about the s38's are just how amazingly flat the response is. I agree I will be hard pressed to achieve that same level of flattness not using their passive cross over.

    It is an experiement.

    Additional benefits???

    1. Can run the Pioneer 1014 up against a Denon 4802 which should be no contest at all given the price / spec differences. But should be an excellent test in my environment same everything else and lots of time to put into it.

    2. I will / should be able to add parametric EQ to every channel even if I go back to my Denon only setup.

    3. Get some additional Pre / Pro features if I choose to use the Pioneer as my Pre / Pro.

    4. Get t actually try true bi-amp for myself for consumer audio / HT

    5. Have a 2nd backup AVR just in case, you know what happens.


    I think it will end up being around $800 total to try this, just gotta see what sort of deal I can get on these weirdo electrnic crossovers.
     
  20. Elinor

    Elinor Supporting Actor

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    >"Elinor to answer your question, it’s pretty well established that active bi-amping (not to be confused with more common passive bi-amping) can deliver significant improvements. Much of the benefit comes from unloading all those passive components from the drivers that can affect their voicing and performance."

    Well, I'm just not seeing a convincing logic in the process. Vince's post is exactly what I would expect in probably 90% or more of cases.

    You say you are removing the passive crossover components? Am I understanding that correctly? So you remove the designer's crossover ... one that is selected and tuned to the exact cabinet and components (tweeters, drivers) that the designer used. And you are replacing that with your own. I have no doubt that, as Vince stated, you can make the speaker sound *different* ... but *better* is going to be highly debatable. Wouldn't the designer design the crossover to make the best speaker he can, with the flattest response (given the limitations of his selected components).

    I was never intending to sound snotty ... but the way I see things ... I'm never, no matter how much I futz around with crossovers and wiring, never going to make my NHT SuperOnes sound like my Dynaudio Contours. It's never going to happen. To me, it is more logical to invest in better grade components. In no way would I suggest that anyone here owns crap and should get rid of it: every one of us here could stand to upgrade our gear, buy better stuff. Why in the world would that be perceived negatively? I sure don't exclude myself from that camp. Geez, *I* would love to buy better stuff than I have ... I'd love to pop in a Theta Casablanca and Bryston Amps.

    Now, a person with lots of time on their hands, compelling curiosity, and a drive to tweak, could maybe coax an iota or two of improvement out of existing stuff ... if they were very very good and persistant at tweaking. Maybe. But it seems unlikely that *most* people, and I say *most* very carefully, are going to have knowledge surpassing that of the speakers's designers.
     

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