Quick & Dirty 4430-Inspired Two-Ways Part II

[Earl K]

Yes,

Thankyou both , David & DRG for the valuable insight .

[grumpy]

FWIW,

1) Network transfer function (assume lossy L2), vert = dB
2) Network input impedance w/ series LCR, vert = ohms
3) Network input impedance w/o series LCR, vert = ohms

-grumpy

[Zilch]

1) Network transfer function (assume lossy L2), vert = dB
2) Network input impedance w/ series LCR, vert = ohms
3) Network input impedance w/o series LCR, vert = ohms

Well, there it is, then. I ordered the additional parts yesterday....

A second thing to note is the notch filter at the back side of the circuit. (C9 L2) It is also tuned to about the same frequency (2500 Hz) and WILL put a dip into the driver response. What they don't tell you is that the inductor probably has a significant resistance built into it. Otherwise it would be very narrow in effect and damaging to the impedance curve. I would model it with a range of resistances (say 1 to 4 ohms) and see what the effect is on the response curve.

Yes. I used 7.5 Ohms total (7.0 plus 0.5 for the inductor) in the circuit construction based upon earlier suggestions here and prior experience with NL200t3. It produced a "familiar" voltage drive, and made a good starting point, from the RTA results.

Thank you for your insight into the circuit design. We can tweak with more assurance, now....

[Zilch]

Here's a very recent example. Notice the lack of notch filters compared to other recent JBL designs.

May we see the entire network, please?

We enjoy analyzing them, quite apparently.

[Hoping it's a TWO-way.... ]

[DRG]

It's from a three-way design. I thought it was interesting to note that the impedance leveling circuits were still being used. I would draw up the full schematic and post it but I think the tech sheet will be available soon.

[Zilch]

I would draw up the full schematic and post it but I think the tech sheet will be available soon.

Thanks, DRG. Let us know with link, when available, please....

[ndnorth]

Hi Zilch,

Good agreement between your simulation and Grumpy's. By the way, what are the two R values for the two different notches that you show?

David

[Guido]

Thanks Zilch! You made it work.....

I can't stand the feeling that we have input from "inside" now

[Zilch]

Hi Zilch,

Good agreement between your simulation and Grumpy's. By the way, what are the two R values for the two different notches that you show?

No resistance for the deep notch, 7.5 Ohms total for the shallow one.

That step compensation occurs frequently, I've found, to let the driver/horn combination play through frequencies where their inherent response is flat, apparently, i.e., "Don't mess with the GOOD stuff...."

It's more precisely achieved in S3100MKII with multiple notches:

http://audioheritage.org/vbulletin/s...205&#post67205

Thanks Zilch! You made it work.....

Only with the help and guidance of many on this forum, including yourself in significant measure, good friend!

The problem with this thread is I've got about 20 pair of "Keepers" now....

[Lancer]

I can't stand the feeling that we have input from "inside" now

[Zilch]

I can't stand the feeling that we have input from "inside" now

Not certain, but I THINK they're allowed to have fun here TOO!

[4313B]

CLIO is in the mail

Bummer!
Now you have to start all over and do all this right.

One thing about CLIO - it's nice to have the raw data files so if you run across something actually worth saving export the data to text files.

Check out D'Appolito's book as Widget suggested.

[Zilch]

One thing about CLIO - it's nice to have the raw data files so if you run across something actually worth saving export the data to text files.

And post them ALL here, right?

[*Groan....*]

I've gotta get me another computer for the "laboratory," too. CLIO's apparently not laptop friendly, alas....

[4313B]

Yeah, it doesn't work too well with a laptop.

Saving the CLIO files allows them to be imported into something like Excel and manipulated easily. You can compare several output files against each other fairly easily that way.

I was kind of kidding about doing all the measurements all over again...

I had to read back through the first few pages again to find out what the goal here was. Have you satisfied your goal?

[Zilch]

I was kind of kidding about doing all the measurements all over again....

Yeah, me too. I expect it'll allow me to accomplish some refinements in the future, and understand somewhat better, is what.

I had to read back through the first few pages again to find out what the goal here was. Have you satisfied your goal?

The goal was stated here:

http://audioheritage.org/vbulletin/s...esto#post45184

It's been one Hell of a trip, and I'm about to wrap it up with a summary. Still have to complete 2507/2235/2435HPL/2352, "Tale of 10 woofers," and LE14/2407/PTH.

The essential elements are clear:

1) Extended bass woofer.
2) Constant (or controlled) directivity horn (or waveguide).
3) Compression driver with usable HF extension.
4) Passive crossover with HF boost.

Can't just throw 'em together, tho, and expect it to work worth a poop....

Regarding "Counterpoint," yes, there's an agenda between the lines, sustained with relentless passion: Big four-ways, nice as they are, are not the only viable option, and for many, not at all a practical one. A variety of two-ways built on the 4430 formula, small and large, can yield very satisfying first-class results, and they're WAY fun to do....