Making Nelson Pass Crossovers (l300) warmer?
Hi all,
I posted the below on another forum and it was suggested that I may actually 'contact the creator' here
Any suggestions would be appreciated thankyou.
A link to that post, with an attachment that runs you through my build is here http://www.audioheritage.org/vbulletin/showthread.php?37411-Your-opinion-on-4333-crossover-please
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G'day All,
I've completed my Nelson Pass crossovers and installed them into the speakers with pleasing results.
I do however have a little issue with the 'warmth' of the sound (please dont start having a go at me for describing sound with words... there just isnt another way in this post), which got me to wondering...
The Nelson pass design for the midrange driver specified an 8 Ohm Lpad rather than the JBL standard crossovers 16 Ohm. (3133 equiv. circuit).
Also - I'm unsure of the impedence of the components in these boxes as they've been around quite a while... How can I simply find the impedence of each driver?... Can I just look at their resistance and estimate from there?
I'd really like to confirm that my impedences are wrong because that would explain the sound to me, and give me a path to resolve the issue.
Oh - also - What should the impedences of each driver using the Nelson Pass crossover be?
Thanks for listening - Any advice appreciated (outside of 'Go Active') Thanks
Pauly
Hi all,
I posted the below on another forum and it was suggested that I may actually 'contact the creator' here
Any suggestions would be appreciated thankyou.A link to that post, with an attachment that runs you through my build is here http://www.audioheritage.org/vbulletin/showthread.php?37411-Your-opinion-on-4333-crossover-please
---------------------
G'day All,
I've completed my Nelson Pass crossovers and installed them into the speakers with pleasing results.
I do however have a little issue with the 'warmth' of the sound (please dont start having a go at me for describing sound with words... there just isnt another way in this post
), which got me to wondering...The Nelson pass design for the midrange driver specified an 8 Ohm Lpad rather than the JBL standard crossovers 16 Ohm. (3133 equiv. circuit).
Also - I'm unsure of the impedence of the components in these boxes as they've been around quite a while... How can I simply find the impedence of each driver?... Can I just look at their resistance and estimate from there?
I'd really like to confirm that my impedences are wrong because that would explain the sound to me, and give me a path to resolve the issue.
Oh - also - What should the impedences of each driver using the Nelson Pass crossover be?
Thanks for listening - Any advice appreciated (outside of 'Go Active')
ThanksPauly
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Your new to JBL aren't you
All the info you require is on that very heritage site.
Search for the model numbers of the drivers you have.
Amazing the amount of info and JBL technical documents they have for free download.
Also search for L300 and 4333.
HINT - Look at the drivers and crossovers used for both EARLY and LATE productions of both.
All the info you require is on that very heritage site.
Search for the model numbers of the drivers you have.
Amazing the amount of info and JBL technical documents they have for free download.
Also search for L300 and 4333.
HINT - Look at the drivers and crossovers used for both EARLY and LATE productions of both.
G'day Pico,
Thanks!
No - I wont be building an amp! Here in Australia, you could buy a really nice amplifier for what it would cost to build one. Also, the amp I'm using to drive them (400W Mosfet) is a pretty good amplifier - certainly can sound wonderful.
Thanks again - I look forward to your comments.
Pauly
Thanks!
No - I wont be building an amp! Here in Australia, you could buy a really nice amplifier for what it would cost to build one. Also, the amp I'm using to drive them (400W Mosfet) is a pretty good amplifier - certainly can sound wonderful.
Thanks again - I look forward to your comments.
Pauly
Hi again Pico
I have been researching a bit more and thought I should mention that I have used foil inductors for L1 and L3 (the series inductors) -
The Values and DC resistance of each are;
L1
2.2MH & 0.59 Ohms
L3
0.18MH & 0.5 Ohms
Hope that helps or makes a difference
Thanks again
Paulytwo
I have been researching a bit more and thought I should mention that I have used foil inductors for L1 and L3 (the series inductors) -
The Values and DC resistance of each are;
L1
2.2MH & 0.59 Ohms
L3
0.18MH & 0.5 Ohms
Hope that helps or makes a difference
Thanks again
Paulytwo
Drivers are mostly resistive so often measuring resistance is good enough to tell the difference between 8 Ohms and 16 Ohms.
You can also look for the specifications on the manufacturers data sheets?
Hi Pico,
No sorry - nor the equipment - Would JBL response graphs do? I may be able to find them.
.
[edit] Here's a plot (the red line) I found...
aaaand.. for the 2420:
Thanks again (and lots!)
Paulytwo
No sorry - nor the equipment - Would JBL response graphs do? I may be able to find them.
.
[edit] Here's a plot (the red line) I found...
aaaand.. for the 2420:
An externally hosted image should be here but it was not working when we last tested it.
Thanks again (and lots!)
Paulytwo
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What about the mid and tweeter?
Often what causes problems is too much energy around 5kHz.
That can either happen with horn tweeters that don't measure flat or stiff mid woofers with resonance issues. Or it could just be an Eq problem.
You might have some success with attenuating the mid woofer. Have you tried that?
Edit: Or is the mid also a horn?
A picture of your speaker is always nice.
Often what causes problems is too much energy around 5kHz.
That can either happen with horn tweeters that don't measure flat or stiff mid woofers with resonance issues. Or it could just be an Eq problem.
You might have some success with attenuating the mid woofer. Have you tried that?
Edit: Or is the mid also a horn?
A picture of your speaker is always nice.
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Hi pico
The mids are jbl 2420 horn drivers.
The mids and tweeters have lpads as the circuit indicates.
The speakers are similar to jbl L300 or 4333 in physical presentation.
Thanks
Pauly
The mids are jbl 2420 horn drivers.
The mids and tweeters have lpads as the circuit indicates.
The speakers are similar to jbl L300 or 4333 in physical presentation.
Thanks
Pauly
What about adjusting the lpad to mid driver (ie attenuate the mid driver), have you tried that?
If that fails my last suggestion would be to do an active crossover just for the woofer.
If that is not an option then get the biggest inductors you can get hold of for your low pass filter eg 8 AWG or 10 AWG.
The crossover itself looks fine, I wouldn't make major changes without seeing in room frequency response measurements of your speaker.
If that is not an option then get the biggest inductors you can get hold of for your low pass filter eg 8 AWG or 10 AWG.
The crossover itself looks fine, I wouldn't make major changes without seeing in room frequency response measurements of your speaker.
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