h66000 h9900 h4365

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Originally Posted by timc

Guido.

Yes you will have to increase the impedance of the HF driver, thus reducing the voltage sensitivity. You do this by simply adding a resistor in series with the driver.

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Hi Tim,

if we decrease woofer impedance we also need to DECREASE midrange impedance. Not increase.
BUT I think this isn't the right way. I confess that I didn't work on it till now as I have to recone 6 woofers till christmas and finish the cc crossovers for a forum member.
I'll look into at as Giskard does. He or me or we will come up with a solution for sure.

It's a bit of a luxury problem how to substitute 4 1501AL with 4 1500AL in an EV 2 configuration but the task itself should be rather interesting... I guess :o:

To prevent this thread to get too dry I added a pic of the "veneer test" for the EV2 cabinets. Will post more pics.

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Originally Posted by richluvsound

Its wonderful to see a thread of real content .

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Be careful, you might get flamed ;)

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Originally Posted by timc

The reworking when increasing the R component only, is purely linear. Meaning you can just increase/decrease the component values by the % amount of the impedance change. Not sure if this is also true for notches.

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I'd prefer to wait until I have time to look it all over in a bit more detail...










Ok... I've looked over everything in a bit more detail ;) and based on the engineering specs it would appear that the original 1500AL is 2 dB more efficient than the 1500AL-1 and 1501AL. Given that, the HF needs to be raised 2 dB. Decrease R8 from 9.1 ohms to 6.8 ohms (or perhaps 6.2 ohms which is worth another half dB) and let me know how that works for you. If you have to go lower than 6.2 ohms then the high pass should technically be reworked. Keep in mind that your coil DCR's are going to affect sensitivity. JBL had 1.3 ohms of DCR on the low 1501AL and 0.8 ohms of DCR on the high 1501AL. You are very probably going to have to use less. I wouldn't be surprised if the HF needs to be reworked a bit, primarily in the 700 to 1 kHz region. I wouldn't be surprised if the LF's end up needing tweaking too. You should be able to end up with a very nice sounding system.

So replacing the 1501AL's with 1500AL's should increase system sensitivity from 96 dB for 2.83V @ 1m to 98 dB for 2.83V @ 1m.

Note that the 1500AL (and K2-S9800) preceeded LEAP. Everest II was the first system that was done with LEAP. The point being that I don't have a LEAP file on the 1500AL/K2-S9800.

Be aware that this is based on the Everest II horn...

Good thing my eighteen month old daughter got me up at five thirty this morning or I wouldn't have had time to look over this today.

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Originally Posted by Guido

Hi Tim,

if we decrease woofer impedance we also need to DECREASE midrange impedance. Not increase.

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Then i have misread something. But the argument stands. Then you do the opposite, by putting a resistor in paralell :)

Here is the schematic we will be working from:

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Originally Posted by timc

Then i have misread something. But the argument stands. Then you do the opposite, by putting a resistor in paralell :)

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Forget it, my head is obviously not working today..... :o:

Removing L14 - 0.5 mH 0.4 ohm shunt inductor

EDIT : Was intended to be the first post in a series following the "What does is all do" post visually showing what each section of the filter affected.

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Originally Posted by 4313B

Here is the schematic we will be working from:

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C7/L8 is a second order highpass section.

C13/R8 is the Constant directivity compensation. This is the R to change to get sensitivity right i think. You will also have to change the capacitor.

L6/R9 i THINK is an addition to the CD compensation

The next three RLC's are notches to flatten the response in the passband.

L14 alters the whole impedance down. Size this to get the same impedance as the woofer in the crossover region. This one only changes things slightly and can not be to small. Then it would alter the response curve in the passband.

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Originally Posted by timc

C7/L8 is a second order highpass section.

C13/R8 is the Constant directivity compensation. This is the R to change to get sensitivity right i think. You will also have to change the capacitor.

L6/R9 i THINK is an addition to the CD compensation

The next three RLC's are notches to flatten the response in the passband.

L14 alters the whole impedance down. Size this to get the same impedance as the woofer in the crossover region. This one only changes things slightly and can not be to small. Then it would alter the response curve in the passband.

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Awesome! You just saved me from wasting my life's time graphing all this stuff and posting it for everyone to visualize. :)

To be honest, I think the quickest way to do this modification is to start from scratch.

First put in the CD compensation, and tilt the curve as you like. Then add the highpass section. The RL part just after the compensation might be needed, or it might not. It is to adjust the impedance i just realized. The resistor in the CD compensation will to a large degree give you the final nominal impedance.

Then add all the notches you require.

Finally use the last inductor to get the impedance juuuuust right.

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To be honest, I think the quickest way to do this modification is to start from scratch.

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Yep, so you guys stop bothering me with PMs. Figure this out yourselves. I have networks to build and have neither the time or inclination to get involved in your issues. Everytime I get sidetracked with these issues someone sends me a PM asking if their networks are done yet.

?????????

What did i do?

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Originally Posted by timc

?????????

What did i do?

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I'm sorry. I should thank you. You saved me from feeling compelled to post a dozen or so graphs.

I think you have an excellent handle on the situation so I'd prefer not to be involved.

Ok, I see your point.

For all others who might be wondering about the "correct" crossover I'll say this:

There is no such thing really. All topologies, slope charateristics, and whatever, have their strengths and flaws. Whatever floats your boat is correct for YOU.

The key to making a good crossover, without spending lots of $$$$$ is to do a good measurement of the drivers in the intended cabinet. Programs like LEAP lets you estimate the measurements to some degree.

Than smash the data into a simulation program. LSPcad tiral version is nice, and free. Then play around with the choosen topology until you get what you want. It's not really much more to it.

A basic understanding of how things work is, as always, a good thing :)

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Originally Posted by timc

Ok, I see your point.

For all others who might be wondering about the "correct" crossover I'll say this:

There is no such thing really. All topologies, slope charateristics, and whatever, have their strengths and flaws. Whatever floats your boat is correct for YOU.

The key to making a good crossover, without spending lots of $$$$$ is to do a good measurement of the drivers in the intended cabinet. Programs like LEAP lets you estimate the measurements to some degree.

Than smash the data into a simulation program. LSPcad tiral version is nice, and free. Then play around with the choosen topology until you get what you want. It's not really much more to it.

A basic understanding of how things work is, as always, a good thing :)

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A perfect quote to end this thread on...

As for trying to maintain some semblence of Everest II voicing? Whatever...

Thanks for disengaging me from this task. :yes: