How to improve the crossover parts in the 1400 Array?

[johnhere]

Hi guys, my head's kinda spinning when researching the 1400s, the xos of 1400 is A big subject, well, Greg provides a method to bi-amp them, there's a sentence "HF level needs to be reduced by 1dB", what does that mean? We follow the instruction and the HF is already been reduced 1dB or do we have to use EQ?


Besides, we all know the stock xos in the 1400 could be improved, and the quickest way to do this is switching to some superior models' crossover parts. Here's my another question, you use DD67000's xos for 4365, and 4365 certainly sound better, and those crossover points in the 67000 also suitable for 4365? If not, what we do, how should we do since there's not much information about changing xo points while keeping the great sound from the superior models' xos. Same thing, just an example, we put 4365's xos into 1400, what should we do then? We would be helpless without help from insiders when facing these xo-points-changing stuffs.

[JeffW]

What is it about the 1400 Array crossover that you find lacking? And generally speaking, substituting a crossover designed to work with a specific set of components for a crossover designed for a different set of components might not work all that well. What part of the 4365 crossover do you feel JBL got wrong enough that substituting a D67000 crossover would fix it?

[rdgrimes]

+1
Very small potential for improvement, very large potential for degradation.

But if one is serious about this, an active crossover and bi-amp setup would be the ticket. That way you make changes by turning a dial and can always go back.

[LowPhreak]

I think one thing johnhere is asking is - aren't the x-o's designed to a specific model's price point? So an Everest x-o has better parts than an Array 1400's and so on, assuming you had the correct frequencies and slopes. Of course a well-designed active with very good parts spec, and with bi-amping, would be better but that would be true for almost any model.

[JeffW]

He mentions changing "xo points" a couple of different times, I don't think substituting "better parts" should change the "xo point".

[DavidF]

Hi guys, my head's kinda spinning when researching the 1400s, the xos of 1400 is A big subject, well, Greg provides a method to bi-amp them, there's a sentence "HF level needs to be reduced by 1dB", what does that mean? We follow the instruction and the HF is already been reduced 1dB or do we have to use EQ?


Besides, we all know the stock xos in the 1400 could be improved, and the quickest way to do this is switching to some superior models' crossover parts. Here's my another question, you use DD67000's xos for 4365, and 4365 certainly sound better, and those crossover points in the 67000 also suitable for 4365? If not, what we do, how should we do since there's not much information about changing xo points while keeping the great sound from the superior models' xos. Same thing, just an example, we put 4365's xos into 1400, what should we do then? We would be helpless without help from insiders when facing these xo-points-changing stuffs.

Do you have a set of Array 1400s? Or thinking about buying them?

[LowPhreak]

He mentions changing "xo points" a couple of different times, I don't think substituting "better parts" should change the "xo point".

But that's precisely what he's asking: "...there's not much information about changing xo points while keeping the great sound from the superior models' xos." IOW, to have the correct freqs/slopes for 1400's while using the better (or similar) components. Obviously some specific values would be different, so you wouldn't have the original/stock x-o in the end.

[JeffW]

We'll just have to disagree until he attempts to clarify. I read this:


you use DD67000's xos for 4365, and 4365 certainly sound better, and those crossover points in the 67000 also suitable for 4365

and it seems pretty straightforward that he wants to know if putting a D67000 crossover in a 4365, taking the crossover points for the D67000 into consideration, will make the 4365 sound better.

The changing the crossover points part isn't from swapping crossover components, but the crossovers themselves.

Again:


Same thing, just an example, we put 4365's xos into 1400, what should we do then?

Sure reads like he's asking about "put(ting) 4365 crossovers into a 1400", almost word for word.

Are the quality of the components even all that different between D67000/4365/1400? I'd think they were all fairly similar, anyway.

Not that it really matters, all academic as it is futile, really.

[JoeNelis]

Just my 2 cents worth, if possible bi amp and use an external electronic crossover like a friend and i are using The DBX 4800. It is amazing with flexibility and you can play with crossover points and see if it's to your taste. I'm using dual 1400ND 's in my new speaker set up with the bessel filter on the bottom end and sounds awesome!!

Also Quality components make a difference, My new crossovers i'm using Jupiter HT 100v caps and sound fantastic and they will need to burn in. I think you have some good options to work with.




Joe.

[Ian Mackenzie]

John is asking a number of questions ...too many in one post or one thread for specific responses.

I would suggest re stating one question per post starting with the highest priority. Presumably the Array 1400

Please Post a link to the comments by GT and relevant threads

Then Open another thread for the other questions.
Dealing with one question at a time will avoid confusion and provide focus and relevance on the right information - subject matter to assist in resolving the question

[timc]

Yes there is potential for an upgrade. The biggest uppgrade of them all is to discard the passive crossover altogether and go active. Not a cheap option but a very good one :)

[johnhere]

Here're the sources of my questions:


The 1400 Array bi-amping
You could read the sentence in those two pics: http://www.audioheritage.org/vbulletin/showthread.php?23763-Bi-amping-the-JBL-Model-1400-Array


About swapping the 67000 xos into the other models:


It doesn't have to though with a network swap. ;) I used both the 4365 and S9900 passive filters and the S9900 passive filters sounded better to me. The DD67000 passive network sounds the best of the three though, no real shock there I suppose.

When Mr. 4313B put 67000/9900 xos into the inferior models, what did he do then? He has no explanations about the crossover points thingy at all.

[4313B]

When Mr. 4313B put 67000/9900 xos into the inferior models, what did he do then? He has no explanations about the crossover points thingy at all.That had nothing to do with the 1400 Array...

For the 1400 Array I bought a second pair of stock 1400 Array networks from JBL. Then I charge-coupled them by removing the stock capacitors and putting the additional capacitors on a board mounted directly over the stock boards. I used the diode method to bias the capacitor pairs. It worked out splendidly. The 1400 Arrays are certainly good enough to warrant the effort. Will I do it for other people? Nope, I don't have that kind of time right now.

Note that when I build or modify networks I run voltage drives on the whole mess to ensure that nothing is shorted or open and that the voltage drives look the way they are supposed to before I start hooking them up to expensive transducers and amplifiers. When I did these 1400 Array networks I measured the stock voltage drives against the biased voltage drives and the results were spot on.


Hi guys, my head's kinda spinning when researching the 1400s, the xos of 1400 is A big subject, well, Greg provides a method to bi-amp them, there's a sentence "HF level needs to be reduced by 1dB", what does that mean? All he is saying is that as soon as one shorts the capacitor the output level of the 435 will increase a dB and one might need to adjust for that. A person might find that they personally prefer a 2 dB drop instead, or none at all.

[johnhere]

Now we ignore the 1400. Please tell us more about the method of modding networks. I believe many of us can't wait to learn the secret of that. Cheers

[Ed Zeppeli]

Now we ignore the 1400. Please tell us more about the method of modding networks. I believe many of us can't wait to learn the secret of that. Cheers

Quite honestly (at least for dolt like me) this is not a simple topic for someone to cover. If you search "1400 arrays CC network" you'll probably find a crapload of info here to satiate your quest for knowledge. I've done similar digging as I have a pair of SAM1HFs that I'd like to pair with some 15s in the future. Ultimately and after a lot of searching I began looking for the right DSP platform to handle those duties. You may or may not come to the same conclusion but I would encourage you to start with that search.

Good luck,

Warren

[Ian Mackenzie]

"If not, what we do, how should we do since there's not much information about changing xo points while keeping the great sound from the superior models' xos."


I see two skills for this:

Design
Proficient in crossover theory and Leap simulation

Execution
Design and construction of active and or passive networks.

Experience
Even if you have the above you need Experience so you don't make costly mistakes.

Equipment and Tools

Even if the above was story booked in a how to guide unless you had the above 4 areas down pat it's not an option.

The notion of up picking someone's brain in a forum thread is an absurdity not to mention the time required to respond to these questions.

I mean it looked like you are reading into snippets of information that it was simply A+B=C

Unfortunately passion often becomes an obsession and then crashes with reality.

We have previously seen people come along blinded by obsession only to see them feed up two or three years later because they could not make it work.

[4313B]

+1

Thank you Ian. :)

[Ian Mackenzie]

Well it had to be said

One day when l retire l might load up what l know and have done in a series of iBooks that someone can buy online and doodle their lives away

[Mr. Widget]

+1

Thank you Ian. :)Yep...

Greg Timbers makes it look easy. It isn't.


Widget

[JuniorJBL]

Yep...

Greg Timbers makes it look easy. It isn't.


Widget

Spot on Widget, B and Ian!


That was easy to say! And just about where it stops!


Thanks for all you do Greg! :applaud:

[martin_wu99]

Where to buy 1400 Array that U.S made? :crying:

[johnhere]

Ian, your language indeed has style, not like anything I've read before, a little similar to Vollmann, but more coherent and more distant at the same time. Who are your favorite writers, may I ask?


I know Leap, good stuff, few can afford it. Actually I find out this is the most-leap-users speaker formus on the planet, this makes me head-ache for almost one hundred seconds.

[Ian Mackenzie]

The reference to Vollmann is amusing! I share nothing in common with this writer.

As far as this non fictional vacation is concerned l like Doug Self's books.

He'an Englishman, quite concise, well researched, presents well and frames the facts in a logical manner.

I don't go out of my way to post "directions" or spot light in every thread.

But sometimes it's more efficient to call it out sooner than later with a moment of "truth" or absolute clarity when the dialogue starts to turn into a "can't be type of situation".

We are all unique with our thought processes.

I recall in my first conversation with someone here many years ago when we were trying to make the crossover network for 2344 bi radial horn work and this NY'er lost his shit when l explained a solution. (surprise surprise)

Well about a week later the penny dropped and we have grown old friends since.

[Robh3606]

Ian is offering you very good advice. It's not easy and you can easily make a mistake while wiring the whole mess together. As an example this is what a CC network for the arrays looks like in schematic form. This is incomplete and does not include the 9 volt battery and wiring to the capacitor pairs to apply the DC voltage.

I built mine with Beryllium drivers so I had to make a couple of changes to the stock networks.

I have both LEAP and Clio to measure and run simulations so I could measure the voltage drives as 4313B said and run acoustic measurements in Clio.

This isn't something where you can just read a few quick posts on the internet and do. It has a bit of a learning curve and the right tools to get it right.

And yes Greg sure does make it look easy!

Rob:)

[honkytonkwillie]

...when I build or modify networks I run voltage drives on the whole mess to ensure that nothing is shorted or open and that the voltage drives look the way they are supposed to before I start hooking them up to expensive transducers and amplifiers.


I have both LEAP and Clio to measure and run simulations so I could measure the voltage drives...

Can someone describe this practice of measuring voltage drives a little bit?

Is it "just" a process where a known signal is measured/scoped across each component to verify proper attenuation?

[4313B]

You take a network and terminate it with the intended transducers or with resistors of the appropriate values. 6 ohms for something like a 2216Nd, 12 ohms for something like a 1501AL-2, 16 ohms for something like a 476Be, etc.

CLIO then makes it easy.
You hook up the CLIO box like in the diagram below but instead of a microphone on the input to the CLIO box you use test leads. Those test leads are connected to the output of each filter of the network and the resulting voltage is measured as CLIO makes a sweep.
For a two way network you would run two drives, one on the high pass and one on the low pass. CLIO can store up to ten sweeps.

Back in the old days we had to do it all by hand writing down the values at various frequencies; There was an HP plotter available back then that would do it with a plug in module but I personally didn't have one, I had to use various test equipment in the physics lab at Denver University. They thought it was funny how I repurposed their gear for testing loudspeakers. They ended up gifting me a very nice (but huge) HP VT audio oscillator and VTVM. Awesome stuff back then for a teenager!

Anyway... once you have those drives you can do neato things with them like import them into LEAP and use them as targets to make new networks, for example, you could measure the voltage drives of the active M2 loudspeaker, import those voltage drives into LEAP along with the impedance curves and frequency response curves of the 2216Nd and D2430K (also measured with CLIO) and then have LEAP come up with a passive filter equivalent. ;)

[srm51555]

So your saying looking at the parts express catalog's crossover chart to find the values for the high and low pass on my M2's isn't going to cut it. :rotfl:

Really though, thanks for posting this. I really had no clue on how the design process worked.

For the record the M2's will stay active.

[Robh3606]

Here is a voltage drive for a network and the raw measurement for the compression driver in Blue and Grey on the top of the graph. The black line is the target curve and the paired lines are the simulated response in LEAP for both drivers in the set. If you look closely you will see that the voltage drive from the network is the inverse of the raw compression driver measurement. This gives you the simulated flat response for the network for a simple point and shoot on axis measurement. Basically you would design the network to give you a voltage drive that gives you your desired response.

Rob:)

[honkytonkwillie]

How cool! It almost looks like cheating though. I'll be doing it the old fashioned way for the time being.

[Ian Mackenzie]

It's not nearly as simple as it looks in practise.

Drivers are real world devices and they all have their quirks.

Sometimes the passive crossovers can interact with the driver passive EQ so you need lots of experience.

It takes skill and experience and a lot of time to get it right.

Then you listen and make adjustments from there.

People like GT do this stuff for a reason.

[Ed Zeppeli]

I'm having some difficulty with the Voltage Drive concept here and how to emulate a given curve using DSP.

What I'm trying to do.


I'm using the DBX Venu360 to actively crossover between my DIY Bass Module and a SAM1HF. At least for the time being I'm using the passive within the SAM to crossover internally in the horn module so I'm only concerned with the woofer/mid frequency here. The woofer is JBL 2234H. I also have a sub to integrate that is a 4645c clone.

74440

The voltage drive to actively drive the 1400 Array was graciously posted here a number of years back...

74442

As mentioned above (thanks) the voltage drive is simply the voltage required to each driver at specific frequencies to produce flat response and is an inverse of the driver's raw frequency response.

What Tools I have at my disposal.

DBX Venu360 with built-in Pink Noise, Sine Wave and RTA as well as multiple PEQ points and multiple crossover slope options. REW on my laptop. Behringer measurement mic.

74441

What Questions I have.



Is emulating the voltage curve above a matter of incorporating both active EQ and crossover slopes?
Given that the Array uses a 750Hz crossover point using Linkwitz-Riley 24db slopes would that be a good starting point?
Is pink noise measured at 1 meter indoors an accurate enough measurement tool to determine response in and around the crossover region?
In a nutshell, what's the best way to approach this? :)


Thanks for taking the time to read!

Warren

[grumpy]

I'm having some difficulty with the Voltage Drive concept here and how to emulate a given curve using DSP.


What, specifically are you having difficulty with? I think you have the overall notion mostly right...



As mentioned above (thanks) the voltage drive is simply the voltage required to each driver at specific frequencies to produce flat response and is an inverse of the driver's raw frequency response.


Well, not really. If you modified your statement to "the voltage drive is simply the voltage required to each driver at specific frequencies to produce a desired response (not necessarily flat), combining
of the drivers (including phase response vs freq), and which may correct some in-band features of the driver's raw frequency response", I'd be happier... and maybe take out "simply" :)

In this case, I believe the voltage drive curve is intended to produce an acoustical/symmetrical crossover, which incorporates the
eq required of the DSP to generate the referenced curves, each driver's acoustical response, and the passive crossover embedded in
SAM1HF box (which is not hugely different than the Array 1400, but is not exactly the same)... all combined to result in the desired
acoustical response, including crossover and slopes.




Is emulating the voltage curve above a matter of incorporating both active EQ and crossover slopes?
Given that the Array uses a 750Hz crossover point using Linkwitz-Riley 24db slopes would that be a good starting point?
Is pink noise measured at 1 meter indoors an accurate enough measurement tool to determine response in and around the crossover region?
In a nutshell, what's the best way to approach this? :)



You can use both crossover and EQ functions to generate a desired voltage curve,
noting that there are a seemingly unlimited number of ways to achieve this... try
to keep it simple (you can also adjust the delay/time-alignment)
Yes (as a target for the -acoustic- response crossover).
Personally, I prefer to use swept sine (REW has this feature).
Go to university for 6+ years, and work at a speaker company for 20+ more :o:
(be prepared to understand that even the folks that know the most about all of this don't know it all)
... sort of kidding aside, the best way to approach this will evolve with your skills, experience, and understanding.

I believe someone posted a brief example design walkthrough by Mr. Timbers... worth digging up (4313b post, perhaps).
If I find it, I'll attach a link.

[grumpy]

Here's what I was thinking of. Entire thread is an interesting read, starting out combining a full-passive crossover system with dsp corrections.

http://www.audioheritage.org/vbulletin/showthread.php?35028-S3900-S4700-dbx-DriveRack-260&p=367128&viewfull=1#post367128

[Ed Zeppeli]

This gives me a lot to work with. Thanks for taking the time to post Grumpy!