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speakerdave
09-30-2003, 06:12 PM
I've assembled almost everything I need for a reproduction of a large format 4-way monitor and am considering the crossover question.

Just read Luxmanlover's comments on an old thread about the handiness of an electronic crossover when setting up a multiway speaker, and in any case, I will need one of these for the bass to bass/mid division.

I've been looking into them and had thought to try and get one of the classics--the Crown VFX2 and 4, the Urei 525, but they seem to be bid up on eBay just now.

There are the JBL crossovers using cards: people seem to have good things to say about them, but I'm not sure of the card supply.

I'm a little wary of the newer ones by various brands because the prices make me expect heavy use of low quality parts--especially IC opamps--dbx for example--or maybe that shouldn't really be a cause for concern.

On the other hand, I'm wondering if for experimental purposes it might make sense to go all the way modern to a digital unit like the Behringer 2496, which would give very great flexibility.

I would appreciate hearing of your experience with these or other worthy possibilities.

I'm interested in 1) Sound quality; 2) usefulness/flexibility; 3) connectivity. Right now my amps are the usual nightmare mixture of RCA, 1/4" T/R/S/ and XLR.

Thank you,

David

speakerdave
09-30-2003, 06:27 PM
Originally posted by Giskard
Well, if I ever finish fixing up all my Crown VFX-2A's you are more than welcome to buy one off me :D

I'm down for that. Send me a PM when ready.

Thanks,

David

scott fitlin
09-30-2003, 06:59 PM
The crown VFX-2 and MX4,s are great sounding units. very clean!

The Urei 525 is also very versatile and has a sound characteristic of Urei products! I like them too! The crowns and Urei xovers are totally user definable and continuosly variable, and I like these features very much!

If your on a budget, there is a company called Marchand, who makes all sorts of crossovers and he will make em to your specification. 6 thru 48db per octave slopes! And 2 way, 3 way, and 4 way stereo is available! These units have frequency cards installed in them, so you have to specify your crossover points! They have front panel output level controls and come with either RCA or XLR connections! Your choice! His units are nicely made, sound good, and dont cost an arm and a leg! you can even get them in kit form, which is the most economical of all!

www.marchandelec.com.

speakerdave
09-30-2003, 07:05 PM
That sounds like a good source, Scott.

Thanks!

David

boputnam
09-30-2003, 07:06 PM
Originally posted by speakerdave
There are the JBL crossovers using cards: people seem to have good things to say about them, but I'm not sure of the card supply.

On the other hand, I'm wondering if for experimental purposes it might make sense to go all the way modern to a digital unit like the Behringer 2496, which would give very great flexibility.


Hey, David...

On the first bit, the 5234A's on eBay are quite inexpensive for what they do. Getting cards configured for what you need might be easier than you think, with some of the wisdom here on the Forum.

On the second bit, :barf: has been the result of my tiresome experiments and experience. Digital is still audible - it simply ain't ready, IMUHO.

scott fitlin
09-30-2003, 07:12 PM
Digital aint ready yet! Analog crossovers, good ones, are still king in my book!

Another thing I have to say is that I prefer 12db and 18db butterworth filters over all others! 18db filters yeild a warmish sound, yet still allows a bit of overlap which I like!

Whichever of the aforementioned devices you decide to go with, Dave, you can get outstanding results used properly!

Robh3606
09-30-2003, 08:16 PM
Well I am using M552 and M553 crossovers form JBL. Work fine very quiet analog crossovers with good features and you can Ebay them usually very at good prices. Only issue is steep L/R 24Db filters are fixed. Even if you don't choose to keep them you can usually get them cheap enough to have one around to experiment with. I have a spare M552 that I use for just that.


http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2560259205&category=23792

Rob:)

Alex Lancaster
09-30-2003, 08:27 PM
What about passive x-overs, at line level?; I have heard them, but not really compared; some are outrageously priced, still the "audiophiles" say it is the only way.

Alex.

scott fitlin
09-30-2003, 09:15 PM
[QUOTE]Originally posted by Alex Lancaster
What about passive x-overs, at line level?; I have heard them, but not really compared; some are outrageously priced, still the "audiophiles" say it is the only way.

Alex. [/QUOT

The only thing about using passives at line level in my opinion is that since they produce no gain, and have no active stages they would be the quietest! But, I need gain. So, for me, I must use active electronic crossovers!

Mr. Widget
09-30-2003, 10:31 PM
Originally posted by Alex Lancaster
What about passive x-overs, at line level?; I have heard them, but not really compared; some are outrageously priced, still the "audiophiles" say it is the only way.

Alex.

What Scott says about the loss of gain is unfortunately true, but if your preamp has enough gain, and most good ones have plenty of gain a passive crossover used at line level is a really great way to go. They are absolutely silent, add no distortion, and don't add that IC opamp or cheap transistor haze that most active crossovers do.

Here is a DIY solution that provides the ultimate in quality at the absolute lowest cost. I posted this link before but check it out. The second link has useful additional information. The first one is a little over simplified.

Widget

http://www.t-linespeakers.org/tech/filters/passiveHLxo.html

http://www.silcom.com/~aludwig/Sysdes/Crossove_Design.htm#Bi_amping

speakerdave
09-30-2003, 11:07 PM
I appreciate the thoughtfulness of these comments you all have offered.

Alex, Scott, Mr. Widget: on passive line level crossovers--

I have run across this idea before, on these forums and elsewhere--in fact I have one--a one-off by M&K that I got on eBay for $20--that I have fooled around with-- and also an 100Hz passive by Audio Research that I tried to use many years ago.

I see this as an option I could employ further down the line, simply because of the complexity it adds to the project even though the result may be a simplification of the whole system--a good goal to keep in mind. I'm not aware that you can buy these anywhere, so each one would have to be made specifically for the two drivers and the AMP!--all based on an understanding of network theory that I've yet to acquire. Thanks for the links--you may discern I've already done some reading on them, to know that the input impedance of the amp is a concern.

For now I think the best option for me is a combination of bi-amping and low level crossover perhaps for the mid/tweeter division. Another consideration is that I will probably want to play these speakers LOUD at times, so the unity gain of an active crossover may be desirable.

But again--Thanks so much!

David

speakerdave
09-30-2003, 11:14 PM
Mr. Widget: " . . . . IC opamp or cheap transistor haze that most active crossovers do . . . ."

Right! I'm actually kind of wary of this, but I think the trade off of getting the Henrys out from in front of the woofer and the bass/mid may be worth it. As Dr. Gizmo maintained, Shangri-la here may be tube crossovers. But that is WAY down the line.


Bo, Scott: Re digital:

I quite agree with you. However, I think in some applications the ability to have crossover and EQ done digitally in one instrument may work well. I would expect, though, that the equipment to do that well now would be very expensive.

David

4313B
10-01-2003, 06:06 AM
"On the first bit, the 5234A's on eBay are quite inexpensive for what they do. Getting cards configured for what you need might be easier than you think"

I've posted the schematics to these cards before but have no idea if they were on this forum or one of the previous forums. If they need to be posted again, let me know.

"Another thing I have to say is that I prefer 12db and 18db butterworth filters over all others! 18db filters yeild a warmish sound, yet still allows a bit of overlap which I like!"

I totally agree, except I'll toss in 6 dB/octave filters as well since I like them for Home use :)

"What about passive x-overs, at line level?; I have heard them, but not really compared; some are outrageously priced, still the "audiophiles" say it is the only way."

Passive line-levels are the "best" regardless of what "audiophiles" have to say. They were the "best" before "audiophiles" were invented :rotfl:

Anyway, use a decent variable active filter to dial in your crossover frequencies and then substitute in the passive line level equivalents when done. Use the best caps you can find such as relcaps (http://www.capacitors.com/) and then use resistors to trim to the right frequency. If you carefully match the caps to the power amplifiers and use high value resistors you won't loose much gain. I've been using passive line levels for 20+ years and they do have their uses :)

I'd personally try some of the actives mentioned by everyone first though. In those active filters that don't have excellent bypass caps across the coupling caps feel free to install some :)

boputnam
10-01-2003, 07:14 AM
Originally posted by speakerdave
Bo, Scott: Re digital:

I quite agree with you. However, I think in some applications the ability to have crossover and EQ done digitally in one instrument may work well. I would expect, though, that the equipment to do that well now would be very expensive. This is true, particularly in sound-reinforcement applications, but not in critical listening (i.e., home or studio). Widget watched me go through a reality-check on this a while back. :bash:

Ian Mackenzie
10-01-2003, 07:26 AM
There should be a diy offering from Nelson Pass soon on passdiy.com.

I expect it will be ruthlessly transparent and user friendly with multiple slope, frequency and Q options using discrete J/fet class A buffers like that attached.


Ian;)

4313B
10-01-2003, 07:30 AM
"There should be a diy offering from Nelson Pass soon on passdiy.com."

Well tell him to hurry up dammit! We need new stuff to build :)

scott fitlin
10-01-2003, 11:31 AM
Giskard is absolutely correct about 6 db slopes. They are great in the time domain and can yeild a very coherent sound quality! transient response is amazing! BUT, there can be some drawbacks as well with first order filters! One, this slope isnt suitable for compression drivers and 2402 and 2405 tweeters!

Another thing to understand is that if you use first order filters you tend to have a very narrow sweet spot! You have to be in one precise spot to get the benefits of what these filters sound like. When you stand or sit, move around the whole sonic picture changes! But, if you can live with being in one particular spot to hear the great characteristics of 6db slopes, its worth it! I, personally, for pro use have found 6db slopes to actually sound very good for sub bass!

Now, choosing crossover points for your tweeters, with 6db slopes has to be chosen carefully as you will have a tremendous overlap with your mid driver or woofer! maybe too much!

But, they are excellent if used correctly!

4313B
10-01-2003, 11:55 AM
"When you stand or sit"

So you have to be lying down? :p
THAT'S what I've been doing wrong all these years! :rotfl:

scott fitlin
10-01-2003, 11:57 AM
Depends what position your lying down in! :duck:

scott fitlin
10-01-2003, 12:23 PM
Originally posted by boputnam
This is true, particularly in sound-reinforcement applications, but not in critical listening (i.e., home or studio). Widget watched me go through a reality-check on this a while back. :bash: Well, I had the BSS FDS-388 Omnidrive! My system IS considered sound reinforcement!

In spite of ALL the things I could do with this $3800 unit, ie; time alignment, parametric EQ, phase alignment, selectable slopes, etc, the one thing I couldnt deal with was the way it sounded!

Last year I auditioned the FDS-366 24 bit DSP processor. Alot better, but still not as good sounding as analog units like Bryston, Crown, or Urei crossovers!

I also auditioned the XTA DSP unit which is even more expensive than the BSS units, and still it isnt what I desire!

Who knows? maybe in another ten years they will have digital audio perfected! I figured they would have gotten it by now! And that they didnt leaves me wondering!

Ian Mackenzie
10-01-2003, 01:14 PM
Hey there are some sweet valvue xovers out there too like Audio Research and Welboune Labs.

Ian

Theres the schematic of the earier Threshold Xover

nostromo
10-12-2003, 07:44 PM
Maybe i can tell you about my system and the crossover issue i found at last.
I have a 5 way multiamplified system.
It is Hartley 24", Onken W (with 2 Altec 416-8C), Altec 1505/with 2x288, Altec 511/802 and Fostex T925.
I tried many crossovers like the following: Furman, Rane, Luxman 302, Ashley 4 way, dbx 234XL/dbx 120 combo. being the Furman the first used and the dbx combo the last one.
At a certain time i was evaluating the purchase of a digital crossover like the Yamaha D-2040, the Broken Siren Song BSS-388 or Accuphase DF-35.
But, somehow the decision to install a digital device in the audio signal path seemed to be like change all the analogue info into digital and then to analogue. And after the bad CD experience i decided to try something else.
And it is an active-passive crossover, with no power supply, designed for the speaker system with 6 db of attenuation works perfect doesn´t have hums or noise it is very silent and is the best unit i have tried.
Ok i have a Krell KBL preamplifier with a 50 volts maximum output.
For the past years using different crossovers i agree with the KIS principle, if you go digital you will get a digital noise today maybe in the near future that can change.
For time alignement as Dahlquist have done it easier to move the components than to chose a digital or electronic solution.

Mike Caldwell
12-10-2003, 07:54 AM
Hello
I may be getting in late on the crossover disscussion.
My use is for live sound production and I use TDM
analog crossovers the CX24x3 and CX24x2 models.
Excellent sounding units.
The bad news is that the company as been sold so what
happens to them is anyones guess!
The original company was small and ran by Tim D. Miller
"TDM"
They had unlimited lifetime warranty on their products.
I had a problem with one of mine a couple of years ago
and when I called them the man himself answered the phone.
They can be found on e-bay from time to time, also they built
crossovers for Fender, they were the same as the CX series
only with different front panel silk screening and the controls
are red and gray instead of blue and gray. I have seen the Fender
units sell at great prices.

Mike Caldwell

speakerdave
12-10-2003, 05:27 PM
Again, I want to thank you all for this help, and I'm sure others will find it useful information too. Since my original posting I have lined up a Crown VFX2A and a JBL 5235 and some cards. Long term plans will be to follow Ian's lead on DIY tube crossovers and also look into the Marchand, which I have already read about some on line. And I will not leave out searching these forums for the many discussions on crossover tailoring--a suggestion I would emphasize for any new readers who see this.

Thanks, many thanks.

David

Ian Mackenzie
12-10-2003, 06:34 PM
We have some developments at diyaudio.com ETA is unknown until the crossover wars subside.

In the mean time I am playing around with some discrete buffers/opamps which are the building blocks of such devices and directly influence the subjective performance.

There are many issues surrounding why active crossovers do/ don't improve performance and the discussions at diy audio cover this well if you are interested.

Ultimately I hope to be able to assist us JBL people with a unit that will exceed the performance of the urie/jbl devices.

Stay tuned

Ian:cheers:

4313B
12-10-2003, 06:45 PM
How are the Crown and JBL working out for you speakerdave?

Mr. Widget
12-10-2003, 11:14 PM
Originally posted by Ian Mackenzie


There are many issues surrounding why active crossovers do/ don't improve performance and the discussions at diy audio cover this well if you are interested.

Ultimately I hope to be able to assist us JBL people with a unit that will exceed the performance of the urie/jbl devices.

Stay tuned

Ian:cheers:


Years ago when I used gear that was little better than a Marantz receiver (actually I was using a Marantz 3800 preamp and Marantz 510 amp) inserting any old active crossover improved the sound of the system. As my electronics improved I became less and less an advocate for active x-overs. Many just add their own crud into the system. I await the affordable Pass alternative with bated breath. :)

Ian Mackenzie
12-11-2003, 01:04 AM
Widget,

I agree entirely,

In fact if you can afford the passive crossover designed correctly with no compromise parts, and the physics allow it to work, then in a SOA system an active crossover maybe a sideways step.

That said, an active crossover of the kind we are talking about, which will cater for switchable slopes, Q , FQ and level will allow the JBL nut to experiement of all manner of beloved drivers on the fly.

Thus blending to his/her taste, mood and the number of bottles drunk.

See this link and down load the pdf for details, its quite a read but very impressive.

http://www.passlabs.com/prodlit/xvr1lit.htm



At the moment the Matrix machines are busy negative engineering the design and the Master is impressed by the progress.

The active buffers will be discrete, using Jfets in class A, either minimalist simple followers or a more elaborate cascoded Jfet X super symmetric design, fully balanced outputs of course.

The usual scene is a bulk order of PCB's once everthing is complete.

I will monitor progress and advise accordingly.

Mouth watering isn't it!, Just a cool $21K...don't ask how much it would cost to make....I don't know. :hmm:

Ian

Ian Mackenzie
12-11-2003, 01:14 AM
Now that is one sexy active crossover box hey:smsex:

Ian

speakerdave
12-12-2003, 02:17 PM
Originally posted by Giskard
How are the Crown and JBL working out for you speakerdave?
They're so CUTE! the way they just sit and patiently wait for me to build boxes.

David

Ian Mackenzie
12-14-2003, 04:00 AM
Some progress here,

If some of you don't need and all bells all tit bits active crossover but more a simple very hight quality 2 way box with provision for 12/18 db slopes or JBL monitor xover options options here is an idea.

I have been looking at a very simple but high quality buffer stages using Dual JFets in a differential / source follower design offering very low noise and distortion with low impediance drive capacility.

The simplicity is such it could be arranged on vero board with provison for fitting the RC values for the filters.

Over the Xmas break I will try and breadboard the design and test it and report on the subjective performance.

I will then consider offering the unit in the form of a black box to interested forum members.

Ian



:)

Robh3606
12-14-2003, 07:44 AM
Hmm

Sounds like an interesting idea. I wouldn't mind the option to change slopes. I like my M552/553 24db L/R crossovers but I would be interested to see what all the hubbub is about 12db vs. 18db vs. 24db slopes. It would be nice to experiment to see if I could hear a difference, when they were properly set-up, and if I had a preference. So far my experience with actives has been the ones I have so it's limited.

Rob:)

Earl K
12-14-2003, 10:25 AM
Hi Ian

Well, you know I'm interested.

If some of you don't need and all bells all tit bits active crossover

What do you plan to exclude and include ?

<>EarlK :)

Ian Mackenzie
12-14-2003, 01:13 PM
I have not thought about it that much.

The idea was a drop in replacement of the 5534/35 that you would throw in the trash can after auditioning the black box.

Least is best here for purity, balanced/unbalanced in out, and option of Eq VLF boost.

This would not be a Pa DBX drive rack, quite the opposite.

Unfortunately the suppy voltage is much higher that the existing 5535 or I would have considered a drop in module.

Ian

Earl K
12-15-2003, 05:18 AM
Hi Ian

I think the overall "feature" set of the 5234/5 series would be fine.

ie; stereo,12 or 18db crossover frequencies determined by plugin cards on molex style pins, variable attenuation ( voltage drive ) on the HF outputs for balancing horns to woofers. Connectors ? How about EuroBlocks on the back ? There's nothing wrong with using tinned wire ends scrunched under pressure-plate fittings.

<> Earl K:)

Ian Mackenzie
12-15-2003, 10:55 AM
Earl,

Thanks for the feedback.

The plug on boards is a good one.

Its very early days for this yet but I will be looking at ease of design and implementation and quality parts, particularly the passive filter elements.

Let me mull over it for a week or two

Ian

Mannermusic
01-18-2005, 04:42 PM
A little noise from an old trumpet player: Have a relatively big JBL system: LE15A, 375/HL89, 077 (in vintage lingo). Have used a Luxman 2003 tube crossover low these past 25 years: 12 and 6 db slopes, +/- 5/8 octave crossover point adjustability or manually change tiny PF caps via soldering iron for more serious variation. Anybody using this antique? Sounds good to these musician/engineering technicians ears; smooth, musical with crossovers at 900Hz and 9000Hz. Kenton lives! What happened to these units - don't see them around? How does performance compare to the newer stuff covered in the crossover forum? :p

JBL 4645
02-23-2011, 02:33 PM
Hey, David...

On the first bit, the 5234A's on eBay are quite inexpensive for what they do. Getting cards configured for what you need might be easier than you think, with some of the wisdom here on the Forum.

On the second bit, :barf: has been the result of my tiresome experiments and experience. Digital is still audible - it simply ain't ready, IMUHO.


Digital aint ready yet! Analog crossovers, good ones, are still king in my book!

Another thing I have to say is that I prefer 12db and 18db butterworth filters over all others! 18db filters yeild a warmish sound, yet still allows a bit of overlap which I like!

Whichever of the aforementioned devices you decide to go with, Dave, you can get outstanding results used properly!

I can hear the sound politics within each comment and since this was 2003 and I didn’t come onboard till 2005 and didn’t buy my first digital crossover till was it 2007? or 2008? Time passes by.

I usual go for a bit of -24db Bessel and L-R.

I assume it’s safe to say digital is now ready, now that 8 years have passed.:)

I have an analogue crossover but I’d dare use it for the HF I think its crossed-off at 500Hz. I could use it for bass/mid. So what do I do? Turn up the level until I hear some kind of disconcerting noise between the analogue and digital crossover?