crossovers

[turbobusa65]

iI' m not trying to start a fude but I'm fixing to buy some crossovers for my La scala's I mostly listen to rock-roll. Both guys's seem very nice too me. And I hate to get either mad made at me.Concering the type of musicI I listen to witch one wold be better for me? mr.Bob's al-3 or mr Al alk's. I'm shure I'll be doing plenty buessniess with the both of them!!! Thank You!!!!

[Guest " "]

ALK's as in the universals?

Either one will work well.

[DrWho]

You could always go with active crossovers and totally avoid having to make the decision []

I like Bob's approach because he maintains the driver specific EQ that Klipsch engineered into their networks. However, steeper slopes have their advantages too...

The best of both worlds would be EQ and steep slopes, which are both really easy to do with active crossovers (not to mention they increase damping and allow for time-alignment).

[Deang]

You don't have to worry about Al, Bob, or anyone else that provides services to the users of this board getting upset with you for asking questions about the products and work.

There is a third option: a slightly modified Type AA using OIMP V-caps. That would be my preference for Rock music. I build those for about the same price as a pair of ALKs.

Unless Klipsch provides the correct data/parameters for an active Heritage set up, or a person has the tools to measure and skillsets to interpret and implement -- I don't see much point in recommending active set ups for the great majority of uses.

[Deang]

!

[Deang]

_

[oldbuckster]

Apples or Oranges ............ they're both fruit !!! Which ever way you go, you'll be happy ........

[ZAKO]

Well ,,, Paul has been wrong before... as he admitted that to Ashworth.

[mas]

ROFLMAO!!!!

Dean, Dean, Dean...

That has to be one of the saddest attempts to discredit multi-way amplification utilizing active crossovers that I have seen yet.

And just out of curiosity, just what model active crossover were they using in <1972 and in 1956? And I wonder just what measurement gear they were using to evaluate this?

Pulling out tools and documentation that were available to the Inquisition in the 1400's is not sufficient to discredit the fact that current tools can actually measure and address the issue of whether the earth is round or whether it revolves about the sun! Regardless of whether PWK wrote it or not! Time, and hopefully, understanding moves forward!

And anyone who is doing so for ONLY the reasons focused upon in the doc is in large measure wasting their time. Perhaps that is why many do not do it for those limited reasons! (Although, as Roy clearly mentioned in an earlier post, limitations in the reproduction of an amplifier's passband does does improve duty cycle and distortion characterisitics.)

A major reason, aside from trying to get mega-SPL increases in efficiency (pardon me while I enjoy the laughter), is signal alignment in order to minimize the superspositional comb filtering and polar lobing response errors that cannot be EQ'd out! A quality active crossover includes signal synchronization adjustments.

And treating time based measuring equipment - available either by purchase for $150 (ETF/RPlusD) or by employing anyone who has time based measurement gear is an easy process. And the subsequent identification of arival times for the purpose of signal synchronization of the acoustic centers is easy. And on access frequency response equalization can be effectively performed on the resultant minimum phase direct signal with the processing capabilities common to many quality active crossovers.

And all of this can be accomplished for less than what many are paying for the exorbitant passives that afford no control over the signal alignment, and thus render any EQ employed unable to correct for the resultant superpositional comb filtering and polar lobing.

Oh, and while speaking of damping factor above 20 (dig out the other DFH document) may be fine with a passive crossover, it is not valid with active xovrs where you can benefit from the increased damping.

And simply employing Crown XTi units for the various passbands seems to include sufficient control over the signal synchronization and EQ parameters to realize all of the pertinent adjustments - and for not much more than for passives crossovers.

The difference is that one method (active multi-way) actually has the ability to address and resolve issues that the other (passives), for about the same money, simply cannot.

[ZAKO]

Dean Dean Dean,,,,,, Thats why you need the electronic xover in that snake pit 402/69 to straight,n out its poor limitations.

[Deang]

"That has to be one of the saddest attempts to discredit multi-way amplification utilizing active crossovers that I have seen yet."

"The first listening test revealed a distinct difference which was tentatively attributed to a difference in frequency response. When this difference was reduced to a subliminal value, there was no aurally discernible difference between the output of the speaker when driven by 3 amplifiers or by a single amplifier."

"And just out of curiosity, just what model active crossover were they using in <1972 and in 1956? And I wonder just what measurement gear they were using to evaluate this?"

It was late 1969. Probably analog stuff built with discrete components instead of cheap opamps. As for what test equipment they used, I have no idea. Doesn't the controlled listening test count for anything?

"A major reason, aside from trying to get mega-SPL increases in efficiency (pardon me while I enjoy the laughter), is signal alignment in order to minimize the superspositional comb filtering and polar lobing response errors that cannot be EQ'd out! A quality active crossover includes signal synchronization adjustments."

I can't hear the difference between aligned and not aligned. Guess I'm just a dumb audiophile. Comb filtering can be reduced by using steep slope passives. Since there is no free lunch, I wonder what performance parameter experiences degradation as you reduce the comb filtering.

"And treating time based measuring equipment - available either by purchase for $150 (ETF/RPlusD) or by employing anyone who has time based measurement gear is an easy process. And the subsequent identification of arival times for the purpose of signal synchronization of the acoustic centers is easy. And on access (did you mean "axis") frequency response equalization can be effectively performed on the resultant minimum phase direct signal with the processing capabilities common to many quality active crossovers."

Right, it's "easy". Get busy everyone!

"Oh, and while speaking of damping factor above 20 (dig out the other DFH document) may be fine with a passive crossover, it is not valid with active xovrs where you can benefit from the increased damping."

I'm not arguing that there aren't "benefits" -- they certainly exist if you have the means to measure, can interpret the data, and properly implement. At any rate, you don't need high damping factors for great audio performance.

"And simply employing Crown XTi units for the various passbands seems to include sufficient control over the signal synchronization and EQ parameters to realize all of the pertinent adjustments - and for not much more than for passives crossovers."

You need three Crowns, which is about $1300. You need to account for going from unbalanced to balanced, and/or need a preamp that won't create an impedance mismatch. The most expensive passives you can buy are $1100, all you have to do is drop them in -- and you don't have to sell the gear you love to do it. Now, there are inexpensive active units, but you still need three amps. And like PK said: "In the hands of the user who doesn't have access to acoustic measuring instruments, it is a certainty that he will apply wrong slopes, wrong crossover points, wrong polarities, wrong component levels, plus of course, trebling the cost and service problems of his electronics." The Crowns are nice, I certainly like mine quite a bit -- but I only had to buy two, and Roy Delgado supplied all of the parameters.

The guy who started this thread was asking about two networks, both which will deliver performance and satisfaction well beyond what he is currently experiencing -- and he won't be out more than $600 either way. He gets them, puts them in, and enjoys his music without all the headaches involved with implementing an active set up. Yes, I disagree with you or anyone who says it's "inexpensive", "easy", and "worlds better".

Now, before anyone accuses me of not being objective because I build and sell passive crossovers, you should know that no one here is getting rich building crossovers -- not even Bob. Even though I like my active set up, I still like passives very much -- and passives built with great parts will have no problem whatsoever hanging with an active set up -- especially an economical one. In fact, the best sound I've heard from the Jubilee was with passives and 300B SET.

[DrWho]

Dean Dean Dean,,,,,, Thats why you need the electronic xover in that snake pit 402/69 to straight,n out its poor limitations.

lolololol - someone doesn't understand power response!

[mas]

"That has to be one of the saddest attempts to discredit multi-way amplification utilizing active crossovers that I have seen yet."

"The first listening test revealed a distinct difference which was tentatively attributed to a difference in frequency response. When this difference was reduced to a subliminal value, there was no aurally discernible difference between the output of the speaker when driven by 3 amplifiers or by a single amplifier."

Most likely any difference in just adding an active crossover mimicing the passive without signal alignment WOULD be subliminal! As little was accomplished except in lessening the load on the amps by limiting the passband! What they did is not an evaluation of what is possible now! My guess is that the the first comparison between a Model T and a horse didn't yield much difference in speed either!
In any event, using that 'whitepaper is absurd!

"And just out of curiosity, just what model active crossover were they using in <1972 and in 1956? And I wonder just what measurement gear they were using to evaluate this?"

It was late 1969. Probably analog stuff built with discrete components instead of cheap opamps. As for what test equipment they used, I have no idea. Doesn't the controlled listening test count for anything?

Nope! No signal alignment, and you simply have an "active passive". In fact, with the phase error of the components and any additional latency inthe unit itself, they probably ADDED to the signal offsets! LOL! So the grand result they evaluated: The same non-aligned system without benefits. And like they say, not much point to that.

Maybe next time we can try their experiement substituting blue components with the black components! Their experiment was indeed "much ada about nothing"! LOL!

Test equipment? ...not much. Kinda like what an RTA does for you now!

My point was they did little and accomplished little with the change as they did not align the acoustical centers.

"A major reason, aside from trying to get mega-SPL increases in efficiency (pardon me while I enjoy the laughter), is signal alignment in order to minimize the superspositional comb filtering and polar lobing response errors that cannot be EQ'd out! A quality active crossover includes signal synchronization adjustments."

I can't hear the difference between aligned and not aligned. Guess I'm just a dumb audiophile. Comb filtering can be reduced by using steep slope passives. Since there is no free lunch, I wonder what performance parameter experiences degradation as you reduce the comb filtering.

Maybe... I'll leave that to your judgement.

On axis you may not hear dramatic lobing - maybe - depending upon the differentials, but as you move off axis the amount and degree of polar lobing WILL increase. It has little to do with our feelings, its basic physics. And with the superposition comes anomalies in the frequency response. Again, its physics. Excessively steep slopes are not a panacea! And simply increasing their slope has been shown again and again to have severe limitations! There is a reason they are not extensively used!

"And treating time based measuring equipment - available either by purchase for $150 (ETF/RPlusD) or by employing anyone who has time based measurement gear is an easy process. And the subsequent identification of arival times for the purpose of signal synchronization of the acoustic centers is easy. And on access (did you mean "axis") frequency response equalization can be effectively performed on the resultant minimum phase direct signal with the processing capabilities common to many quality active crossovers."

Right, it's "easy". Get busy everyone!

Yup, on 'AXIS'.

The measurement is no more difficult that using an oscilliscope or any of the fancy frequency domain electronics gear you have! But instead of simply wandering about wringing your hands and saying "its oh so kompleekated!!!!" and denigrating its usefulness, you obtain it and use it. I can only imagine your response when someone suggested buying a VOM! And gee, we finally found a use for an RTA!

"Oh, and while speaking of damping factor above 20 (dig out the other DFH document) may be fine with a passive crossover, it is not valid with active xovrs where you can benefit from the increased damping."

I'm not arguing that there aren't "benefits" -- they certainly exist if you have the means to measure, can interpret the data, and properly implement. At any rate, you don't need high damping factors for great audio performance.

OK, now benefits aren't benefits. Let's go further, no one here needs Klipsch Heritage speakers and CERTAINLY NOT$1100 passive crossovers!!!!!!!

"And simply employing Crown XTi units for the various passbands seems to include sufficient control over the signal synchronization and EQ parameters to realize all of the pertinent adjustments - and for not much more than for passives crossovers."

You need three Crowns, which is about $1300. OK, you got me. But let's see, for an investment of >$1100 yields 3 Crown XTis versus a pair of passive crossovers. Let me think.... You need to account for going from unbalanced to balanced (Oh oh! Yes, a cable you can make yourself! or at most a $50 adapter!), and/or need a preamp that won't create an impedance mismatch. The most expensive passives you can buy are $1100, all you have to do is drop them in -- and you don't have to sell the gear you love to do it. ROFLMAO! Now, there are inexpensive active units, but you still need three amps. And like PK said: "In the hands of the user who doesn't have access to acoustic measuring instruments, it is a certainty that he will apply wrong slopes, wrong crossover points, wrong polarities, wrong component levels, plus of course, trebling the cost and service problems of his electronics." The Crowns are nice, I certainly like mine quite a bit -- but I only had to buy two, and Roy Delgado supplied all of the parameters. And with those amps, you don't need the crossover! The DSP functionality has this built in! One reason they were specifically mentioned!

The guy who started this thread was asking about two networks, both which will deliver performance and satisfaction well beyond what he is currently experiencing -- and he won't be out more than $600 either way. He gets them, puts them in, and enjoys his music without all the headaches involved with implementing an active set up. Yes, I disagree with you or anyone who says it's "inexpensive", "easy", and "worlds better".

Let's see, obtaining that information is insurmountable without investing in equipment? Really? I guess asking is pretty difficult! Easy? OK, plugging in a couple of connectors is pretty difficult as well. And works better? Yes! It does.

Now, before anyone accuses me of not being objective because I build and sell passive crossovers, you should know that no one here is getting rich building crossovers -- not even Bob. Even though I like my active set up, I still like passives very much -- and passives built with great parts will have no problem whatsoever hanging with an active set up -- especially an economical one. In fact, the best sound I've heard from the Jubilee was with passives and 300B SET.

Passives can be acceptable in a minimum phase configuration. In anything less they are a compromise. And in Heritage speakers they approach an abomination. And since compromises are such a problem that some would still advocate $600 or $1100 passives, I personally find either far too expensive for what they do - and more importantly, do NOT do. If you are going to consider doing any of this, the expense alone warrants doing it correctly. Otherwise I would save the money and use it for something else! (And cheaper active alternatives are definately available!)

But as we are advocating $600-$1100 passives that completely fail to the address the basic fundamental physics of signal alignment, it might be worthwhile to ask just what we are correcting?And as such, this is an expensive change to correct what? So what is it again that they fix?

The frequency response complete with more precise comb filtering and polar lobing? Maybe we should be evaluating the precision of the resultant comb filtering and lobing due to more precise components!?

If you simply want to replace a few aged components and will be satisfied, save the money and learn to solder.

If you are trying to solve more substantial fundamental issues, do it right. And that involves active crossovers with signal alignment - and any needed equalization to an aligned minimum phase signal. And if someone is serious about this, my gut feeling says that the information necessary to do this can be obtained from alittle time invested, or from others on the forum, and even from Klipsch if they understand what one are doing.

The fact is, there isn't much to be gained in denying the fundamental physics involcved. And understanding that part IS easy!

[Deang]

lolololol - someone doesn't understand power response!

Sure he does, he was just trying to irritate me.

mas, did you say something?

[DrWho]

I think you make a good point about being able to correctly dial in an active crossover, Dean.

I
was just thinking though...how is it any different than the engineering
practices being employed by the aftermarket crossover builders? []
I'd love to see some dirty curves that show where the changes are
happening between the old and new.....not that I don't think
differences/improvements don't exist, but I just wonder if the same
level of measurement capabilities were being used to facilitate the
final outcome (not to mention it would be interesting to see what the
differences actually are). If it was all done by ear, then I'd argue that it's easier to dial in an active crossover by ear than it is a passive crossover (you don't have that deadtime inbetween soldering to confuse what you're hearing).

[gaspr]

Do any of you think that the day will come where some amp manufacturer will come out with a six channel digital amp, with unbalanced inputs, with crossover capabilities, and with DSP including EQ and signal alignment, and at a reasonable price?? Not asking for too much am I? Might as well ask for measurement capabilities as well.[]

[PrestonTom]

In answer to the original question, you can spend $20 or you can spend considerably more.

If you are handy with a soldering iron, I would get the same value caps (don't worry about the other components unless they have been damaged) from Parts Express or whoever. I have used Solens and the parts were only about $20-25 for a pair. This is a simple way to refresh the caps you will will get a noticeable change in the sound (I did not say it will necessarily be dramatic - since you are not changing the design). This is a very good value (performance relative to price)

If you want to go the next step there have been schematics posted by John Albright and by ALK (universal). These do involve a redesign but are still reasonable in price. This would also be a good value, IMO

The next steps after this (and remaining passive) can become rather expensive (fancy parts, steep slopes, etc). It is difficult to judge the value (performance re: price) IMO. With passive crossovers, you will not get the ability to time-align the drivers (although, not all folks will hear the benefit of this). If you are not handy with a soldering iron, there are others who can do this for you and recommend various options. Those folks have already been identified and can they can give well-reasoned advice.

The ultimate, IMO, would be to go for the bi- (or tri) amped configuration and use an active (digital equalizer). This will provide steep slopes and time alignment also. The electronics can become costly ($300 to 3000) and whether it will be a good value (performance re: price) is in the "ear of the beholder". This option is not a simple one and would require further research and assistance (there are many ways to do it wrong). At that price, there may be other things that will give a much bigger bang for the buck (speaker choice and room acoustics). Just my opinion ...

Good Luck,

-Tom

[mas]

Gee, I have to run out and I come back and there is no scathing personal attack...I am rather disappointed!

PrestonTom makes a good suggestion. As I also mentioned, replacing the aged caps for a few bucks will give you the biggest ROI without messing with the whole can of worms.

But to accomplish more than that, there are more effective methods on which to spend your hard earned money.

But one thing that does bear mentioning. The notion that you can simply employ increasingly high slope crossovers to solve passband interaction problems is, in a word, nonsense.

Sure its easy to minimize the percent overlap with regard to magnitude, but you incur significant phase shift. And combined with the electro-acoustical slope of the driver and enclosure (which you CANNOT ignore!) you get strange phase shifts that vary from the well-behaved assumptions. And the resultant interaction quickly results in the magnitude ceasing to sum flat.

All you have to do with a 'scope'(that displays magnitude and phase) is to keep increasing slopes and watch the phase wrap that results in an almost impossible ability to sum the magnitude flat. And except for attempts specifically aimed to maximize SPL, the sound quality quickly goes to hell.

The irony is that most systems have gone back to at most an 8th order LR at 48 dB/slope, with still more going lower. (And note, that includes the driver voice coil which as an inductor acts as a 1st order 6dB/octave filter as well as, say, a vented enclosure which adds another 6dB/octave filter - all of which are interactive in the scenario...)

So its time for everyone to let the notion that extreme slopes solve the afomentioned problems, die the death it deserves, as this issue is not simply solved by maximizing slopes! And to be honest, above a certain point, they sound terrible!

The irony is that the addition of DSP adds still further complexity to the solution.

[Coytee]

Gee, I have to run out and I come back and there is no scathing personal attack...I am rather disappointed!

Ok...I'll try...

With all your loving comments about passives, alignments, lobes and the like... I thought I was reading comments by Al K... are you related?

[]

(ok, how'd I do?)

[Deang]

Do any of you think that the day will come where some amp manufacturer will come out with a six channel digital amp, with unbalanced inputs, with crossover capabilities, and with DSP including EQ and signal alignment, and at a reasonable price?? Not asking for too much am I? Might as well ask for measurement capabilities as well.

Heck, it's already here. Call Shawn and have him set you up with his modified Panasonic/Behringer combo.