Bi-Amping with Active Crossovers - Pros and Cons

Discussion in 'Audio Hardware' started by Soundgarden, Jan 9, 2022.

  1. monte4

    monte4 Senior Member

    Location:
    Ontario Canada
    My own personal opinion on this would be that 2 lesser amps actively bi-amped would sound better than a single higher quality amp non active provided the lesser amps are still of good quality.
     
    Last edited: Jan 11, 2022
    izeek, Randoms and Soundgarden like this.
  2. Soundgarden

    Soundgarden Forum Resident Thread Starter

    Location:
    Bend, Oregon
    Hah. A review your earlier posts provides the answer too. Lots to keep track of in digesting all this :)
     
    Randoms likes this.
  3. monte4

    monte4 Senior Member

    Location:
    Ontario Canada
    Yes, as he had done so many setups, he knew pretty closely what my system should sound like once active. He said with my speakers he never has to adjust the gain of the mid/base from the center position and he set up the treble by listening to some solo acoustic guitar. He dialed back the tweeter card one notch and I could hear how much more natural the guitar sounded when he made the adjustment.
     
  4. ltusler

    ltusler Forum Resident

    Location:
    Minneapolis
    Speaking as an active active system user, I am pro active.
    I was fortunate to pull the trigger on a pair of Klipsch Jubilee's. They came with a Xilica XP-4080 DSP Processor and settings developed by Roy at Klipsch.
    Currently its set up as a 4.2 system. Meaning 2 channels on the horns, 2 channels on the bass bins, and 2 active sub woofers.
    Everything that can be is connected with XLR cables and running on pro voltage levels.
    You can see the connections and signal chains in my profile.
    I am very satisfied with the performance and adjustability.
    Also I am lucky to have met a guy over on the Klipsch Community that has the same setup and deeply understands how to tune with REW and is happy to help with the tuning in my room.
     
    Soundgarden and monte4 like this.
  5. monte4

    monte4 Senior Member

    Location:
    Ontario Canada
    Also with going Aktiv with Ninka's, I don't think you even need to open up the speakers and disconnect the passive crossovers to go active. Everything is done from the rear of the speaker. And you are correct that I could use the same Activ cards. I have thought about upgrading to some used Ninka's but I worry that to sell my existing Keilidh's the internal crossovers would have to be hooked back up and I'm not comfortable doing that myself as there is some soldering involved on the actual internal crossovers and as I previously stated my dealer unexpectedly passed away. My nearest dealer is now a 3 hour drive.
     
    Randoms likes this.
  6. SandAndGlass

    SandAndGlass Twilight Forum Resident

    I don't have "hang-ups, I am only pointing out the issues in moving from internal factory crossovers to a line level active or passive crossover and bi-amplification. It's not that it cannot be done, just that it can be more complex than it appears on the face of things.

    Whdn we have threads like these, keep in mind that they are being read by other members who might not be actively posting to this thread.

    The forums are a tremendous resource of information that the general public can access and refer to. Keeping in mind, this is not just the present but for (hopefully) many years to come.

    Someone wanting to do some research on active crossovers or bi-amping, might Google these terms and have this thread come up in the search engine results.

    When I post, I make an effort to keep this in mind and to provide clarity to others who may also be reading this thread.

    Your particular speakers, if we are talking about the Klipsch Heresy are a bit easier to tackle than the typical non-horn home speaker. I will attempt to further clarify the subject below.

    Please keep in mind, that my viewpoint is driven by issues that exist in the real life with regard to active/passive line level crossovers and bi-amping, as I have done and do both.

    Yes it does. Not saying that it cannot be achieved but it is better accomplished with those who are knowledgeable in what they are doing.

    I myself am a consumer, not a speaker or crossover designer, though I do have a half century experience in working with audio and electronics.

    As such, I look to the speaker manufactures to provide expertise with their products, much the same way I look to a custom crossover designer, such as ALK Engineering for crossover design.

    Pro-audio speakers are different than home speaker design. Let me explain the major differences. This is a Polk Audio LSiM707 (now discontinued). It could easily be just about any average tower speaker. It has multiple drivers and crossover networks which are carefully engineered to provide not only the correct crossover frequency but the correct gain and slope to each driver.

    [​IMG]

    Here is an Altec A7, which is a commercial theater speaker, it is not really that much different than heritage Klipsch speakers, such as the Heresy.

    Here is a close up of one of the A7's. The Yorkville UCS-1 commercial horn sub is to the left. That's a Decware EL34 based Zen Torii Jr. sitting on the top of the sub.

    [​IMG]

    This is run by of the custom AP12-500 ALK crossovers. Here you have a bass cabinet and a separate horn. This is effect two separate speakers. You could use a different horn or a different bass cabinet.

    The bass cabinet can play up over 1-kHz. While the horn can play down to 500-Hz.
    The crossover frequency can essentially be set to crossover anywhere you wish between these two frequency ranges.

    It is a matter of personal choice, the bass frequency here rolls off at 500-cycles and the horn frequency picks up at 500-cycles.

    The only issue is that the horn has a higher sensitivity rating than the bass bin. This is addressed with a shelving control on the crossover. This provides adjustable attenuation to the HF signal going to the HF horn. By adjusting the shelving control, you balance the relative loudness of the horn to the woofer.

    Want to bi-amp? Simple, just use an online active or passive crossover and two power amps. It's just as easy to do one as the other. The only thing that needs to be addressed is that the either the crossover circuit or the power amp, needs to have a means of adjusting the volume level to match the horn to the bass cabinet.

    The sub to the left of one of the A7 cabinets as a Yorkville UCS -1, 15", horn loaded commercial sub-woofer, which is powered by a Crown XTi-2000, running 1,600-Watts in the bridged mono mode.

    I point this out, because a commercial sub woofer has now been added. It has a online crossover that filters out anything over 40-Hz. and allows anything 40-Hz. or less to pass through to the power amplifier on the sub.

    There is a super-tweeter above the horn and it has a crossover that allows signals above 6-kHz. to pass on through to the super-tweeter.

    Through the use of four crossover frequencies and four separate drivers, a two-way cabinet has now been turned into a full range 4-way system.

    Trying to do this with a typical home speaker (as shown above) is so much more complex.
     
    Last edited: Jan 11, 2022
    Soundgarden likes this.
  7. avanti1960

    avanti1960 Forum Resident

    Location:
    Chicago metro, USA
    The key to all this are the speakers. How much is there to gain going active with such a vintage box?
    Why not have the passives rebuilt ?
     
    SandAndGlass likes this.
  8. Randoms

    Randoms Aerie Faerie Nonsense

    Location:
    UK
    Back in the day I converted multiple pairs of Keilidhs from passive to active and guess you simply reverse that.

    You remove the lower mid / bass unit and the instructions are on the crossover. You would have to remake the 4 links and move the 56 strand cable across.

    As you can see, the lands where you solder are very robust and this is a simple job for anyone who knows which end to hold a soldering iron!!

    Edit. The photo below shows the passive set up.


    [​IMG]



    @monte4 , the Ninkas are a big improvement from the Keilidhs and sound stunning both in active mode with Chakra and passive on the end of Linn Klimax Solos. S/H they can be an absolute bargain...

    Converting them is simplicity itself as long as you have (they were supplied with the speakers), or make a tool. Simply move the plates to a configuration you want: absolute brilliance!

    [​IMG]

    [​IMG]

    [​IMG]
     
    Last edited: Jan 11, 2022
    monte4 and SandAndGlass like this.
  9. SandAndGlass

    SandAndGlass Twilight Forum Resident

    Or replaced with upgraded crossovers?
     
  10. Soundgarden

    Soundgarden Forum Resident Thread Starter

    Location:
    Bend, Oregon
    Certainly a fair question. My answer has to do as much with wanting to learn about and try bi-amping than with having a specific set of expectations. Based on everything I've read, though, there ought to be something to gained by doing this well. Question is whether it's both audible and worth the time, investments, and added complexity. Part of me would be pleased with that outcome. Another part of me would be pleased to know that my system, as is, already sounds excellent in comparison.
     
    Randoms likes this.
  11. Soundgarden

    Soundgarden Forum Resident Thread Starter

    Location:
    Bend, Oregon
    That is an option as well. I wanted to start with the speakers as they were intended. So did the builder. So we have a historically accurate baseline.
     
    Randoms and SandAndGlass like this.
  12. SandAndGlass

    SandAndGlass Twilight Forum Resident

    This has been very well thought out..

    However... Do I spy an "evil" ferrite core inductor on the lower left quarter of the PCB? :D
     
    Soundgarden, monte4 and Randoms like this.
  13. SandAndGlass

    SandAndGlass Twilight Forum Resident

    What exactly are these speakers?
     
  14. Randoms

    Randoms Aerie Faerie Nonsense

    Location:
    UK
    They were "only" about £500, but yes, very well thought out.

    The next generation of Linn speakers were child's play to convert!
     
    monte4 and SandAndGlass like this.
  15. Soundgarden

    Soundgarden Forum Resident Thread Starter

    Location:
    Bend, Oregon
    Acoustic Research AR-3a.
     
    SandAndGlass likes this.
  16. Randoms

    Randoms Aerie Faerie Nonsense

    Location:
    UK
    Whilst I wouldn't attempt what you are doing, I fully understand your reasoning, certainly don't underestimate your friends' ability and look forward to reading your findings.
     
    izeek and Soundgarden like this.
  17. Soundgarden

    Soundgarden Forum Resident Thread Starter

    Location:
    Bend, Oregon
    I'm a little surprised by that actually given your earlier responses and enthusiasm around (certain types of) active crossovers. But I appreciate the send off all the same ;)
     
    Randoms likes this.
  18. SandAndGlass

    SandAndGlass Twilight Forum Resident

    Just wanted to confirm we are on the same speakers.

    The question I have here is what has been pointed out by 62caddy. The drivers in the AR-3a's are OK but nothing really stellar.

    They are not really sensitive, dynamic or are able to handle a lot of power. They do have nice cabinets though!

    Main reasons for bi-amping a speaker are to eliminate crossover losses and to provide more power and focus that power to the specific drivers.

    I think the addition of a 2nd power amp to these speakers would be of questionable value?

    The drivers can not take much power, they have fairly low sensitivity and require some power to get them up and running. But there is a limited window between "up and running" and exceeding the amount if power that the drivers themselves can realistically handle.

    The drivers themselves are not particularly resolving and there might be questionable benefit trying to squeeze more out of this orange?

    I see a pair of these in reasonably good condition as being worth about $750, noting that this is very subjective.

    What kind of condition is your pair in?

    Has any restoration been done to them?

    [​IMG]

    I would give this some further consideration before throwing a lot of time, money and energy at them?

    I like vintage speakers and own some W60, W70 and W90 Wharfedale's from the same period. Which I think are excellent sounding speakers and can be driven loud and clean with a small 22-Watt tube amp.

    I think that someone is seriously underestimating the effort that will be involved in recreating and matching the AR3a's internal crossover network.

    These efforts may be better served if directed toward your Heresy's?
     
    62caddy likes this.
  19. Randoms

    Randoms Aerie Faerie Nonsense

    Location:
    UK
    I'll rephrase my comment!

    Without your friend's know-how, I wouldn't attempt what you are intending.

    Yes, I very much appreciate what an active system can offer and had many years enjoying the effortless, but tuneful, detailed, dynamic performance I was hearing.
     
    SandAndGlass and Soundgarden like this.
  20. 62caddy

    62caddy Forum Resident

    Location:
    PA
    For whatever it may be worth, the collector world places a strong emphasis on stock condition (or restored to stock) while generally taking a dim view of equipment that's been modified from OEM. The exceptions are for mods that are done by the manufacturer itself or by one of its original engineers. That said, I would have zero interest in purchasing, owning or getting involved with someone's "Frankenstein" which will not only reduce value, but make the item that much more difficult to sell, if and when the time comes. If one is unconcerned about the consequences, by all means hack away to your heart's content.

    Biamping, whether active or passive is one of the most misunderstood and grossly overestimated practices in the hobby but some will never be satisfied until they've gone down the trail for themselves regardless of the lack of objective evidence to support it. Anecdotal accounts do not impress me.

    It is my opinion that modifying a pair of AR3a's is a fool's errand if the objective is better sound. If better sound is the goal, far wiser, simpler, economical and productive to buy a better speaker to begin with. There are countless newer speakers that will run rings around an AR3a no matter how many amplifiers you throw at it, no matter what mods are done to it. It would be akin to modifying a Ford Model T in hopes of achieving the performance of a 2021 Corvette ZR1.

    That is all I have to say on the matter.

    62caddy.
     
    Last edited: Jan 11, 2022
  21. Soundgarden

    Soundgarden Forum Resident Thread Starter

    Location:
    Bend, Oregon
    The AR-3as are fully refurbished. They may or may not be the end-game speaker here. The Heresies are still here for sure. I also may have a custom infinity project headed my way. One where I build custom cabinets ( I can do this really well) and a friend does the electronics (he can do this really well.)

    I see the experiment as worthwhile but am not at all surprised at suggestions about the efforts being of potentially limited value with the AR-3as. We'll see what happens. Sometimes following my curiosity involves navigating winding roads...
     
    SandAndGlass likes this.
  22. Soundgarden

    Soundgarden Forum Resident Thread Starter

    Location:
    Bend, Oregon
    Roger that. Over and out!
     
  23. 62caddy

    62caddy Forum Resident

    Location:
    PA
    Love it when people solicit "advice" when their mind was already made up to begin with - only to bristle when they don't get the answer they wanted. :rolleyes:

    @Soundgarden Best of luck in your audio endeavors.
     
  24. Soundgarden

    Soundgarden Forum Resident Thread Starter

    Location:
    Bend, Oregon
    Oh I've gotten plenty of answers I wanted. Lots of useful information and backs and forths that I've found extraordinarily valuable. I was just saying I heard you loud and clear. Not sure what you're sour about or why my own personal ambitions would be upsetting to you.
     
  25. 62caddy

    62caddy Forum Resident

    Location:
    PA
    My apologies then if I misinterpreted your previous response.
     
    Soundgarden and SandAndGlass like this.

Share This Page

molar-endocrine