Richard C. Heyser's Klipschorn review

[Groomlakearea51]

[

If you knew what you were doing, I'd wager that you could build yourself an equal performing active crossover for around $200.

Ok!!! Talk to us!!! Build that bad boy!!! Do one and I'll even pay for the parts!!! (I would like a back SAE size case...) We can test it here!!! Seriously!!! You can call it "Dr. Who's Magic Bus"!!

[mas]

Active crossovers need not be overly expensive.

And they are available from a great many (primarily pro) vendors.

For instance, the Rane AC24 (list $999) is available retail for about $578. What makes it raqther unique is that it is 4 way (Sub/LF/MF/HF). And despite its front end analog appearance front end, it is digital.

But if you do not need the 4 way control, many other units are available.

Note, there are many different configurations, and many assume a particular driver's acoustic origin to be the reference, so you need to check this for suitability. For instance, if you have a more common dynamic LF driver and horn MF and HF like the Cornwall, then the Rane SAC23 or AC23 may be great for you (check the exact specs as several only delay the LF/MF to match the HF). And these can be had for about $125. So they are great deals if they meet your application.

But in general, the market for crossovers is a relatively large one, albeit traditionally in the pro arena where this technology is the norm - not in the home market.

And yes, units like the Behringer can be had for much less. You just need to read the specs (as in capabilities), evaluate the construction quality relative to the intended use (naturally, for instance, those designed for continuous road use are going to be over-designed relative to those intended for casual static installation) and make your decisions accordingly.

But, in any event, there is NO need to buy some fancy 'magic in a box' solution costing thousands of dollars.

{But you will have to pardon me as I find great humor in the notion that this technique is speculation and has never been done; when in fact it is a very common and very accepted practice. What does that tell you about the expressions that this technique is pure speculation?)

[ClaudeJ1]

[

If you knew what you were doing, I'd wager that you could build yourself an equal performing active crossover for around $200.

Ok!!! Talk to us!!! Build that bad boy!!! Do one and I'll even pay for the parts!!! (I would like a back SAE size case...) We can test it here!!! Seriously!!! You can call it "Dr. Who's Magic Bus"!!

You may be on to something, here Dr. Who. I used to be a world renowned Printed Circuit designer in my prior career, so I can do the PCB and packaging design, you provide the schematic.

[Deang]

"Final crossover that I liked was a fairly extreme with bass simply ending at 450; mid starting at 400, ending at 9200, high starting at 8800."

The Klipschorn midrange driver/horn combination doesn't go a lick past 6kHz. So I guess what sounded good to you had almost 3000 cycles of suckout.

[Duke Spinner]

"Final crossover that I liked was a fairly extreme with bass simply ending at 450; mid starting at 400, ending at 9200, high starting at 8800."

The Klipschorn midrange driver/horn combination doesn't go a lick past 6kHz. So I guess what sounded good to you had almost 3000 cycles of suckout.

[:|]

[DrWho]

If you knew what you were doing, I'd wager that you could

build yourself an equal performing active crossover for around

$200.

Ok!!! Talk to us!!! Build that bad boy!!! Do one and I'll

even pay for the parts!!! (I would like a back SAE size case...) We can

test it here!!! Seriously!!! You can call it "Dr. Who's Magic

Bus"!!

You may be on to something, here Dr. Who. I used to be a

world renowned Printed Circuit designer in my prior career, so I can do

the PCB and packaging design, you provide the schematic.

Truth be told, we're already building this product for one of my design

labs...but we're going a step further. We're designing an active

crossover preamp that also has digital amps built in (we're calling it

an active amplifier). The whole thing should cost under $500 to build -

and we're using the same Sharc DSP's that DEQX is using.

Depending on how things turn out, the amps might be in a totally

different enclosure - in which case we'll essentially have a 6 Channel

amplifer and a 2x6 active crossover.

The only catch is that we don't get to keep the device unless we fund the project ourselves... [*-)]

I don't wanna sidetrack the thread too much with my project, but the

whole reason

we're pursuing it is because we feel there are significant improvements

to be achieved by implementing an approach that allows time-alignment.

The other reason for the approach is to have the compensation EQ's

necessary for speaker systems like the K402 that has constant

directivity and flat power response. In fact, it seems like all the

cutting edge horn designs require dramatic levels of EQ (which in the

pro

world isn't a big deal because everyone already has the DSP processing

available). I believe the thrust behind this trend has been the fact

that speaker designers are considering more than just the frequency

response when they design a speaker. Guys like Heyser have provided the

tools necessary to help engineers take this other criteria into account.

[Islander]

So I could make my La Scalas sound even better by using a digital crossover to time-align the drivers for not much money? I've upgraded the system enough for this year, but that may be something to consider for next year. With Scalas in a home situation, is the difference that noticeable? Since a delay below 400 Hz and having the harmonics over 4500 Hz leading a bit, relative to the midrange where most of the music is, might not be that obvious, is it worth the extra expense and complication? I mean, if you're not totally obsessed, that is.

Does each driver need its own amplifier channel and can unused channels from an AV receiver be used, if it's a 7.1 receiver with only 3 channels being used, for example? I'm driving my mains with an outboard power amp and only using the receiver to drive the center and two rear speakers. I get the impression that the mid and high amps wouldn't need anywhere near the power the woofer would need.

The surround modes would be out, but 7 channel stereo, with each channel's level being adjustable, might do the trick.

Hmm, now that I think about it, each channel's delay is adjustable in the receiver through the distance settings. No frequency control, though, so feeding a full-range signal to the tweeters would be a bad idea.

[kev313]

If you knew what you were doing, I'd wager that you could

build yourself an equal performing active crossover for around

$200.

Ok!!! Talk to us!!! Build that bad boy!!! Do one and I'll

even pay for the parts!!! (I would like a back SAE size case...) We can

test it here!!! Seriously!!! You can call it "Dr. Who's Magic

Bus"!!

You may be on to something, here Dr. Who. I used to be a

world renowned Printed Circuit designer in my prior career, so I can do

the PCB and packaging design, you provide the schematic. 

Truth be told, we're already building this product for one of my design

labs...but we're going a step further. We're designing an active

crossover preamp that also has digital amps built in (we're calling it

an active amplifier). The whole thing should cost under $500 to build -

and we're using the same Sharc DSP's that DEQX is using.

Depending on how things turn out, the amps might be in a totally

different enclosure - in which case we'll essentially have a 6 Channel

amplifer and a 2x6 active crossover.

The only catch is that we don't get to keep the device unless we fund the project ourselves... [*-)]

I don't wanna sidetrack the thread too much with my project, but the

whole reason

we're pursuing it is because we feel there are significant improvements

to be achieved by implementing an approach that allows time-alignment.

The other reason for the approach is to have the compensation EQ's

necessary for speaker systems like the K402 that has constant

directivity and flat power response. In fact, it seems like all the

cutting edge horn designs require dramatic levels of EQ (which in the

pro

world isn't a big deal because everyone already has the DSP processing

available). I believe the thrust behind this trend has been the fact

that speaker designers are considering more than just the frequency

response when they design a speaker. Guys like Heyser have provided the

tools necessary to help engineers take this other criteria into account.

Hey Doc (or Mas) (o menos) - Why do you think there is such a huge difference between the products available in the home arena vs. the pro or commercial market?  Even Klipsch, a company that has extensive products lines in both areas, seems pretty far from offering active crossovers and DSP for the home audio speakers. ((maybe that is also a question for Roy)) 

[DrWho]

So I could make my La Scalas sound even better

by using a digital crossover to time-align the drivers for not much

money? I've upgraded the system enough for this year, but that may be

something to consider for next year. With Scalas in a home situation,

is the difference that noticeable? Since a delay below 400 Hz and

having the harmonics over 4500 Hz leading a bit, relative to the

midrange where most of the music is, might not be that obvious, is it

worth the extra expense and complication? I mean, if you're not

totally obsessed, that is.

Does each driver need its own amplifier channel and can unused

channels from an AV receiver be used, if it's a 7.1 receiver with

only 3 channels being used, for example? I'm driving my mains with an

outboard power amp and only using the receiver to drive the center and

two rear speakers. I get the impression that the mid and high amps

wouldn't need anywhere near the power the woofer would need.

The surround modes would be out, but 7 channel stereo, with each channel's level being adjustable, might do the trick.

Hmm, now that I think about it, each channel's delay is adjustable

in the receiver through the distance settings. No frequency control,

though, so feeding a full-range signal to the tweeters would be a bad

idea.

I'm not sure if lascalas would benefit much from it or

not...at least in the LF to MF crossover transition. It would depend on

the acoustical centers for the squakwer and bass bin. 400Hz has a

wavelength around 3 feet and I can't see there being much more than a 1

foot offset between the LF and MF. The ~2 feet between the squawker and

tweeter is definitely an issue considering the crossover is around

6000Hz which has a wavelength around 2 inches.

You could exeriment with fool's bi-amping in your configuration if you

could completely isolate the MF and HF crossovers. The LF could still

be powered by the same amp as the MF.

That said, in an acoustically untreated room, I think early reflections

would mask the benefits achieved by time-aligning the drivers...

[Islander]

"Fool's bi-amping"? Smile when ya say that, stranger!

Seriously, if the benefits would be minimal in my case, I'll just enjoy my system and spend my money on more music. Thanks for the advice. All Blues is the evening program on KPLU and I'm liking what they're playing tonight.

BTW, the crossover in a Scala (AA in mine) from MF to HF is at 4500Hz, but an inch or two either way doesn't matter.

[DrWho]

Hey Doc (or Mas) (o menos) - Why do you think

there is such a huge difference between the products available in the

home arena vs. the pro or commercial market? Even Klipsch, a company

that has extensive products lines in both areas, seems pretty far from

offering active crossovers and DSP for the home audio speakers. ((maybe

that is also a question for Roy))

I think there are a few issues at play...

• An improperly configured active crossover will do more harm than

  good. Unless you've had years of practice, it is very difficult to dial

  in an active crossover by ear. Even then it is still difficult.

  Proposing that an audiophile implement measuring equipment in their

  home never goes over well.

• An active crossover involves more expense. You have the cost of

  the crossover on top of needing to double or triple the number of amps.

  Not only is this an expense for the customer, but also for the dealers.

• Advertising time-offsets and EQ curves implies that there is

  something wrong with the speaker - especially in a market generally

  uneducated about such things.

• You also introduce an extra set of A/D, D/A conversions. There

  are certainly losses involved when these transformations take place.

  While they can certainly be minimized, they cannot be ignored

  completely. That said, there is absolutely no reason why an active

  crossover couldn't accept a digital input from a CD player. This keeps

  the signal in the digital domain, thereby avoiding any possible

  nasties. There aren't very many active crossovers that accept digital

  inputs, but it seems that trend is slowly changing.

• Anything digital is voodoo to the hardcore analog crowd
• Common acoustical environments might swamp out the benefits too -

  early reflections essentially behave like additional point sources.

  While you may be able to correct for some of the time-smear, you won't

  be able to fix all of it and thus might not even notice a difference! I

  can see this being especially problematic in very small rooms and/or

  highly reverberant rooms.

In all honesty, I see the future of high fidelity audio taking the path

of active loudspeakers (like what has occured in the recording studio).

The manufacturer can implement all the processing they want inside the

amplifiers and since the audiophile won't see it as an extra box he

won't have to worry about a more complicated signal path. It also would

allow the signals to be transferred digitally, keeping the quality at

the same level all the way through. The only downside to this approach

is that it doesn't cater to the tweaking tendancies that many often enjoyed in

this hobby, so it'll probably never happen.

Nevertheless, I think most of your questions can be answered in light

of what happened with the Jubilee. Roy brought the speaker to the

market with an active crossover in mind and then everyone here demanded

that he build a passive. He went ahead and designed the passive and

then suddenly the speaker was too ugly that it didn't matter what it

sounded like...

[mas]

Hey Doc (or Mas) (o menos) - Why do you think there is such a huge difference between the products available in the home arena vs. the pro or commercial market? Even Klipsch, a company that has extensive products lines in both areas, seems pretty far from offering active crossovers and DSP for the home audio speakers. ((maybe that is also a question for Roy))

Several reasons.

First you need to look at the market from a strategic marketing POV.

Tri-amping requires not only an active crossover, but a minimum of three 2 channel amps; and potentially there is still the subwoofer to consider.

This can (but needn't necessarily ) add significantly to the total investment.

The speakers (especially the Heritage line) are already perfectly capable of being outfitted this way as they come from the factory.

But, let's stop and look at this from a strategic marketing POV.

Klipsch does not manufacture active crossovers. Is there an incentive for them to enter this market, considering where the majority of the market is, and is heading, cost of entry, expected time and amount of return and other associated lost opportunity costs? No.

Although it might be to their advantage to offer a package featuring an exisitng co-marketed third party crossover package as an option.

But let's take a step back and look at the market in general...

Is the high end market, especially the 2 channel market, expanding or contracting? Sadly speaking, the high end is not expanding.

And the average buyer will probably not appreciate the differences, as evidenced by the lack of understanding about simple concepts as we routinely witness here. If so many here don't understand the significance and the advantages, will the average off the street buyer? Again, probably not.

Would Klipsch benefit from increased revenue or sales due to offereing such a package. Again, I suspect not.

Although I think it would be wise to make available the basic driver/crossover/offset specs to facilitate configuring an active crossover should one wish to emply one. Far from causing problems, it would simply enable others. Witness the commercial products.

While some here may be surprised to hear this, the pro market has a higher appreciation for many of the advantages offered by the developments of the last 30 years.This is partly because they address major performance limitations in distributed systems. But it is also due to effort to educate folks and the need for companies to support such education.

For a sampe of this, just pick up a copy of a trade publication and a 'high end' hi fi magazine and look at the focus of the articles! Sorry folks, but the hi fi magazines are primarily marketing rags. There is little of substance regarding theory or practical applications, whereas this dominates the pro trade publications.

In fact, I currently know of no one in the pro audio that would spec a distributed system without signal alignment! Compare that to the percentage of folks in the hi fi market that even understand the abstract value of it! Is it reasonable for Klipsch to attempt to overcome and to achieve a market tipping point independently? I would say no.

Again, such configurations are the norm in the pro market, ranging from SR, to distributed systems to pro monitors, where many have been bi and tri amped utilizing signal alignment for decades.

Additionally, no one in that market challenges Berger, Jannsen, Todrank, Cary, et.al., regarding room treatment. In fact, their waiting lists have historically exceeded their available resources!

So I think one has to look at the return versus the investment. In a shrinking market segment, high end 2 channel audio is not in a position to be increasing the necessary system resources when there is substantial market pressure from the rapidly expanding 'room in a box' home theater market segment, and where (even so many here) think that "room EQ" features in a receiver actually achieve effective room treatment.

So it makes sense to address the existing market and maximize one's penetration, rather than fight the good fight trying to change the market's thinking as they attempt to prove a point.

Unfortunately, this also means that much of what is sold meets market expectations rather than exceeding them and expanding the capabilities of one's experience.

So it seems that the small percentage of folks who realize the opportunities to optimize a system, and have the resources to do so, do have the opportunity with relative ease (once they are aware of the potential and practicality).

They simply have to go to a pro sound vendor such as Northern Sound & Lights. Or they can go to Best Buys and buy a new 'theater in a box' with magical 'room correction' circuitry.

Guess where most are going?

[DrWho]

"Fool's bi-amping"? Smile when ya say that, stranger!

Seriously, if the benefits would be minimal in my case, I'll just enjoy my system and spend my money on more music. Thanks for the advice. All Blues is the evening program on KPLU and I'm liking what they're playing tonight.

BTW, the crossover in a Scala (AA in mine) from MF to HF is at 4500Hz, but an inch or two either way doesn't matter.

Well even at 4500Hz the mis-alignement is critical enough to be audible. I would probably recommend upgrading the entire MF/HF section into a single driver to turn your lascala into a 2-Way. With the right top-end, you might even be able to align close enough to the lascala LF to be able to compensate in the passive crossover.

[Islander]

2-way? Hmm. Should I get a 402 horn? It might be pretty closely aligned to the LS bottom end, as you say, with minimal compensation needed. It might even increase the sensitivity slightly.

[DrWho]

While you might get closer alignment with the 402, you're right back at needing gobs of EQ to compensate for the constant directivity - which is better handled with DSP than a passive crossover. Nevertheless, there is a passive available for that purpose, though it's rather expensive too.

[Islander]

Okay, so the K400 is the best bet for the LS. Well, it's Saturday night, so I'm going to relax in front of my non-aligned 3-way La Scalas and listen to some music. Check you guys later!

[DrWho]

I think you're missing the point if you think the K400 is the best bet...it's just a cheaper solution.

[ClaudeJ1]

I think you're missing the point if you think the K400 is the best bet...it's just a cheaper solution.

But it may just be more "cost effective" as far as the law of diminishing returns is concerned. The Khorn 60th anniversary edition sounded overall better than the Jubilees at the pilgraimge, mainly because of the great room they were in. I'm sure if the Jubilees were in the same room it might have been a different story. I think Jubs with the 402 a priced similarly to regular K horns, except they only come in Henry Ford Model T Black. But hey, even PWK himself concluded they were better, so I will eventually have those. I'm sure they will be much easier to time align since they are a 2-way.

One thing's for sure, the Jubs with the 402 horn don't need a tweeter as the highs are as crisp and detailed as anything I've ever heard.

[pauln]

Just a thought experiment...

If one corrected the mid-tweeter position error in the La Scala by removing the tweeter from it's front mount and repositioning it back, and higher; exactly where would be the best placement?

[Coytee]

One thing's for sure, the Jubs with the 402 horn don't need a tweeter as the highs are as crisp and detailed as anything I've ever heard.

Claude, I presume you're aware of this, but the Jubes as we heard them in Indy was already using a tweeter driver, the K69 on the K402. It's the midrange driver they dropped.