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luddite

Is It Worth It to Bi-Amp Heritage speakers?

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I'm sure this question has been asked, and probably answered, multiple times.  

I've had Khorns driven by a Mc275 version VI, Belles driven by Mc2125's X2, and Belles driven by a Mc7270.  

Have never felt the need to bi-amp anything, but perhaps I've just never experienced audio-nirvana.  

Now I'm down to a pair of Belles and the afore mentioned Mc275, with a RSW115 helping out with the bottom end.  

I have a Mc2200 sitting around, occasionally driving a pair of Forte II's.  

Would I get any benefit if I bi-amped the Mc2200 (SS, 200 WPC), and the Mc275 to the Belles with or without the sub?  

The crossovers on the Belles are upgraded.  McC27 preamp, Merrill modded Thorens TD160 HD TT, MCD 7007 CD.  

And assorted peripherals.  

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I think that the question is better posed as "how much better is bi/tri-amping sound that monoamping".  That's really the question since in no circumstances have I heard of nor witnessed anything getting worse from multi-amping.  It always has sounded better. 

 

Getting at least the woofer out of the same electrical circuit as the midrange and tweeter is a pretty big deal.  Getting the midrange and tweeter out of the same circuit allows you to time align them using digital delay.  That has been a big deal.  Getting the extra reactance of the passive crossovers out of the circuit also tightens up the woofer's response considerably--direct coupling the woofer to the amplifier output channel.

 

Another question is "which Klipsch Heritage speakers benefit the most?".  In my experience, they all do--pretty much equally.  The Heresy woofer needs a bit of power to have authority.  Getting that electrical circuit out of the midrange and tweeter circuits makes a difference in terms of isolating the back EMF of the woofer due to the moving mass effects, and especially if you can time align the drivers using delay. The Cornwall woofer has a lot of moving mass, so getting that driver out of the same circuit and the midrange and tweeter cleans up their output dramatically when listening at moderate and higher listening levels (above ~75 dBA/1 m). 

 

The three Heritage models with horn loaded bass (Khorn, La Scala, Belle) benefit greatly from multi-amping simply because you can take out those big time misalignments with the midrange, and the tweeter time misalignment with the midrange.  Once you hear the effects of multi-amping and time aligning, you'll never want to return to monoamping in my experience.  It sounds that much better.

 

So the bottom line usually is: are you going to time align the drivers?  This makes more difference than just providing separate power to the woofer and the other two drivers (midrange and tweeter).  To time align all drivers, you need a good DSP crossover.  Those can now be had for less money than a new set of higher performance passives.

 

Chris

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I guess the question which needs to be asked is the biamping going full-range through the crossovers or after low-level splitting? 

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Running two amps through the passive crossover is known as "fool's biamping". It's far better to split the signal before the amps, preferably with a digital loudspeaker processor.

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17 minutes ago, Don Richard said:

Running two amps through the passive crossover is known as "fool's biamping". It's far better to split the signal before the amps, preferably with a digital loudspeaker processor.

 

Absolutely correct!

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10 hours ago, Chris A said:

Getting at least the woofer out of the same electrical circuit as the midrange and tweeter is a pretty big deal.  Getting the midrange and tweeter out of the same circuit allows you to time align them using digital delay.  That has been a big deal.  Getting the extra reactance of the passive crossovers out of the circuit also tightens up the woofer's response considerably--direct coupling the woofer to the amplifier output channel.

I did this with my Quarter Pie Bass horns while using passive on the mid and tweet. Worked great as a passive/active hybrid approach at the time.

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You can physically move the tweeter backwards away from the listening position until time alignment is achieved on-axis with the midrange and retain the passive network between the midrange and tweeter (i.e., the Bruce Marvel trick that he has used on his La Scalas for many years). This works well, except that off-axis you still have time alignment issues, and typically this moves the tweeter centerline higher off the floor away from the midrange centerline (more than 1/4 wavelength at the crossover frequency), but it's certainly a lot better than not time aligning on-axis.

 

Chris

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If you like to complicate things and add more circuits to the signal path, then go for it. I've never heard an improvement when I tried bi-amping my K-Horns, but you may.

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24 minutes ago, kevinmi said:

If you like to complicate things and add more circuits to the signal path, then go for it. I've never heard an improvement when I tried bi-amping my K-Horns, but you may.

 

Could you explain what you did when you tried it?  Could you also describe the configuration of your Khorns (i.e., original drivers and crossovers)?  And did you run any acoustic measurements on the resulting SPL response?

 

Chris

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2 minutes ago, Chris A said:

Could you explain what you did when you tried it?  Could you also describe the configuration of your Khorns (i.e., original drivers and crossovers)?  And did you run any acoustic measurements on the resulting SPL response?

The only thing stock on my K-Horns is the veneer on the bass cabinet!

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Three questions above, not one...  Could you address the other two?

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10 hours ago, Don Richard said:

Running two amps through the passive crossover is known as "fool's biamping". It's far better to split the signal before the amps, preferably with a digital loudspeaker processor.

 

I agree active crossover has the best chance of getting the most/best out of the speakers, but we still don't know what was had in mind in that regard with the original question.

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I did not want to bring up the potential need for an active crossover with bi-amping with my original question.  

But, as retaining the passive crossover negates the benefits of adding the second, or third amps, the active crossover is part of the deal.  

So now the question becomes:  what adds more to the bi-amping exercise, the amp or the crossover?  

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There's benefit from feeding the low and high crossover inputs separately, with separate amps (and I'd guessed that was your intention), it's just that it's very incremental as compared to going with active crossovers.  It would cost you next to nothing to try.  My guess is once you get the gains set properly you might notice an improvement.  Maybe.  And you'll just leave it that way anyway until you need that second amp for something else.

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4 hours ago, luddite said:

So now the question becomes:  what adds more to the bi-amping exercise, the amp or the crossover?  

Active crossover use requires multi-amping, so it isn't possible to separate their two contributions.  So I have to ask the question: why do you phrase your question as you did?  It makes a distinction that really doesn't exist. 

 

In post #2 of this thread, I answered your original question by going to the root issues that cause differences (issues) in sound quality in mono-amped setups, chiefly:

  1. the back-EMF/EMI of woofers affecting the other drivers/horns due to much higher moving mass (even horn loaded),
  2. time misalignment of the drivers/horns, and
  3. the loss of amplifier damping of the woofers and other drivers due to the added reactance of the passive crossover circuits removing the amplifier's control from direct coupling to the drivers

 

There are other effects, such as Ohmic heating of the passive crossover networks, significantly changing the crossover frequencies of the electrical/driver filters, reducing power to the some drivers but not other drivers, and creating non-linearities in output of the passive crossover networks with input power (compression distortion), etc.  Passive networks are like using the brakes of an auto to control speed while opening up the throttle to the engine.  All the electrical power that is not needed is turning into heat instead of not being generated in the first place through controlling down the engine throttle. It's really an insane way of doing the job, if we weren't so historically accustomed to seeing this approach used in powering loudspeakers.

 

Of these three main effects enumerated above, if you are talking about Khorns exclusively (and not Klipsch Heritage loudspeakers in general as the title implies), the largest single effect of the three sources is a toss up because the time alignment issues are most pressing for this loudspeaker relative to other Heritage models. 

 

If you play your Khorns fairly loudly (above ~83 dB(C)/m) regularly, then the back-EMF/EMI issues will emerge as a big factor, along with the audibility of the loss of woofer/horn damping--if mono-amping.  So it's a bit of a guess which factors will be most prevalent for you personally.

 

This is what I've found with DSP crossover use and multi-amping: if you like the clean sound of the horn-loaded bass bins over direct radiating bass, multi-amping using DSP cleans up the sound up much more due to all three factors being addressed at the same time, and also brings more authority to the bass due to lower phase growth of the loudspeaker and higher effective power to the woofers to damp the moving mass effects.  This is just like removing high pass filters from the circuit tightens up the bass, as well as more effective power and damping to the woofers.

 

Chris

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I typed this before Chris A posted the comment above, but it covers some other aspects of what’s involved and what is gained.  Quite a few members have upgraded their La Scalas and Belles this way, and found it very worthwhile.  I certainly have.  Of course, in some situations, it makes more sense to just go for it and buy a pair of Jubilees and be done.  That’s something else to think about.

 

If you’re interesting in bi-amping your speakers, you might want to consider going 2-way and using the tweeter drivers and horns from the Jubilee.  The Pro Theater driver it uses is able to cover the range of both the stock squawker and tweeter, enabling 2-way operation, which eliminates one crossover point, and the phase issues that go with it.  I don’t have the knowledge to explain that in any further depth, so if you’re wondering about that particular aspect of the conversion, certain other members are able to explain it.

 

The drivers usually used are the K-69-A (good) and the K-691 (better, and the one currently supplied with Jubilees).  The horn designs may be newer than the K-77 horn and are definitely newer than the venerable K-400/410 midrange horn.  The stock 400/410 horn is an exponential type, while the much newer K-510 (small) and K-402 (huge) are modified Tractrix types, which have certain acoustic advantages, which, again, I’ll leave to more knowledgeable members to explain.

 

There’s a variety of active crossovers that can be used:  the E-V Dx38 (discontinued, but used ones are widely available), the E-V DC-One, the Yamaha SP2060, and the latest one, the Xilica.  These can tailor the frequency response far more accurately than any passive crossover, and the lack of any components other than cable between the power amps and the drivers makes for cleaner sound.

 

You’ll need two amplifiers, of course, and they can be identical models, or not.  Having each amplifier covering only half the frequency range reduces distortion, and finally, those active crossovers allow the woofers and tweeters to be time-aligned, which is also very good.

 

My avatar shows one of my La Scala IIs with a K-510 horn sitting on it, although the Scalas are currently wearing the much larger K-402 horns.  Both are good.  The 402 is better, but its looks aren’t for everyone. That choice is up to you.

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4 hours ago, Chris A said:
  • the back-EMF/EMI of woofers affecting the other drivers/horns due to much higher moving mass (even horn loaded),
  • time misalignment of the drivers/horns, and
  • the loss of amplifier damping of the woofers and other drivers due to the added reactance of the passive crossover circuits removing the amplifier's control from direct coupling to the drivers

 

To the OP:

 

Item #1 in the quote is the only thing you'll gain by full-range bi-amping through your passive crossovers (unless, perhaps, you need the extra amplifier headroom which will marginally become available).  This is why I said it's "very incremental" above.

 

Repeating myself again, it'll cost you next to nothing to try while you mull it over about going active.

 

Another factor I believe I noted was that your source is predominantly analog.  You did mention some digital equipment so you must not be totally averse to it, but you'll definitely be going digital (and back) to do actives right.

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1 hour ago, glens said:

Another factor I believe I noted was that your source is predominantly analog.  You did mention some digital equipment so you must not be totally averse to it, but you'll definitely be going digital (and back) to do actives right.

I've always been a bit puzzled by this part: digitization wasn't mentioned by the OP.  This is not a consideration worthy of discussion because there is no audible effect of this.  I don't mention it because of that.  The ability to correct for certain loudspeaker issues is audible, so I mention those improvements.  The source of the problem generally lies in the minds of those that seem to be worried about it.

 

Chris

 

 

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I agree with everything Chris says.  For me, bi-amping and going to a digital active crossover, 2-way setup was a HUGE improvement over stock La Scalas.  Probably the largest improvement I have ever made to my system with the possible exception of room treatment.  It is not subtle.  You can essentially remove most of the worst bottlenecks in your system.  Others have covered the details already, so I'll leave that alone, but just know that the improvement is real and very significant.  It takes some time, money, measurements and persistence to get it right, but it is absolutely worth it, IMO.

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On 3/16/2020 at 11:27 AM, Chris A said:

Three questions above, not one...  Could you address the other two?

It was about 10 years ago when I was experimenting with bi-amping, and I didn't have any means for testing at that time. I have recently purchased a laptop and a Umike, but I need someone like you to help me figure out how to use it properly. I'm still not interested in bi-amping, but I am building my own horns, and would like to be able to compare them and see the different patterns with different sizes.

  As far as the configuration of the KHorns: bass bins are enclosed, using Crites cast woofers. Midrange is a 210hz tractrix wooden horn with a 2' throat. Currently using BMS 4592 mid drivers. Tweeter is a wood tractrix horn with a 1 inch throat. Driver is a Selenium D220ti. Crossovers are either DeanG universal type with 400/6000 crossover points, or my own build universal type with 400/4500 crossover points.

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