A ProgRock evening with JBL 4312SE speakers

shakti

Active Member
May 9, 2015
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Cologne, Germany
#22

MRJAZZ

[Industry Expert]
Jan 21, 2014
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#24
I bet they would! PBN, is that right?

I absolute loved the more conventional HWW version shown at RMAF last October. Have you heard both? If so, how do their presentations differ?
Yes.........
The Symmetrical array (Dapolito) is 35 K MSR versus 30 K for the HWW. Sonically the Symmetrical is more open, spacious and generally more three dimensional.... both are superb and have few peers, ( and no superiors, that I have heard....and there’s not much that I haven’t heard) at their respective price points ( 30 k HWW, 35 K Symmetrical).....
Cheers...
 
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Duke LeJeune

[Industry Expert]/Member Sponsor
Jul 22, 2013
189
72
28
Princeton, Texas
#25
Yes.........
The Symmetrical array (Dapolito) is 35 K MSR versus 30 K for the HWW. Sonically the Symmetrical is more open, spacious and generally more three dimensional.... both are superb and have few peers, ( and no superiors, that I have heard....and there’s not much that I haven’t heard) at their respective price points ( 30 k HWW, 35 K Symmetrical).....
Cheers...
Thank you for the additional information. Being a speaker manufacturer myself, imo the BEST thing about these big PBN speakers is, they are north of my price range so I don't have to compete against them!

I built some big custom symmetrical WHW's for recording studios a few years ago. They were destined for big metal stands but initially they sat on the floor of my living room. I heard the image at the height of the upper woofer (with eyes closed), but my wife heard the image at the height of the horn (again eyes closed). This discrepancy has puzzled me. Anyway it looks like Peter has the horn at seated ear height so it wouldn't be an issue.

I assume the Symmetrical is a true 2-way (both woofers running all the way up to the crossover frequency).

Do you know whether the M2!5 a "2.5 way" as its name seems to imply, with the lower woofer rolling off considerably below the crossover region?
 

MRJAZZ

[Industry Expert]
Jan 21, 2014
202
44
28
#26
Thank you for the additional information. Being a speaker manufacturer myself, imo the BEST thing about these big PBN speakers is, they are north of my price range so I don't have to compete against them!

I built some big custom symmetrical WHW's for recording studios a few years ago. They were destined for big metal stands but initially they sat on the floor of my living room. I heard the image at the height of the upper woofer (with eyes closed), but my wife heard the image at the height of the horn (again eyes closed). This discrepancy has puzzled me. Anyway it looks like Peter has the horn at seated ear height so it wouldn't be an issue.

I assume the Symmetrical is a true 2-way (both woofers running all the way up to the crossover frequency.

Do you know whether the M2!5 a "2.5 way" as its name seems to imply, with the lower woofer rolling off considerably below the crossover region?
I believe both woofers operate full range up till they transition to the horn (approximately 800HZ.......
 
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Robh3606

Active Member
Aug 25, 2010
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Destiny
#27
I believe both woofers operate full range up till the transition to the horn (approximately 800HZ....... "

That would make sense. Love that waveguide works well with passive EQ you don't need DSP like the M2 to get a good solution for CD compensation. Can't believe JBL sells them!?

Rob :)
 
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Duke LeJeune

[Industry Expert]/Member Sponsor
Jul 22, 2013
189
72
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Princeton, Texas
#28
I believe both woofers operate full range up till the transition to the horn (approximately 800HZ....... "
Very interesting. I think you are correct; I looked at the crossover-under-plexiglass on the back of the cabinet and don't recall seeing the monster inductor that a 2.5 way configuration would imply.

I heard no vertical discontinuity from a fairly close listening distance at RMAF, so evidently their crossover is low enough that that's not an issue.

Peter was doing something in the pair he showed at RMAF last year, in addition to his charge-coupled capacitors, that really caught me by surprise. I'm not sure he'd want me to spill the beans about it, so I will just say that his crossover design is EXTREMELY thorough!!

Can't believe JBL sells them[the waveguides]!?
My guess is that Peter Noerbaek has friends at JBL. Really good friends.
 
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Robh3606

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Aug 25, 2010
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#29
"Peter was doing something in the pair he showed at RMAF last year, in addition to his charge-coupled capacitors, that really caught me by surprise. I'm not sure he'd want me to spill the beans about it, so I will just say that his crossover design is EXTREMELY thorough!!'

CC networks have been used in JBL statement speaker crossovers since the 80's. I have used them in my DIY and clone system upgrades for years. If you go over to Lansing Heritage they are all over the site. Also really easy to convert an existing crossover you can use either a battery or diodes. Gets expensive though, as you double the values and capacitor count. It's just a T with a pair or capacitors with a 3 meg resistor in the bottom leg to the hot side of a 9 volt battery negative to ground as a quick example. I would assume he is using the same configuration as JBL.

As far as the crossover with a typical large format CD it's a parametric compensation. So a parallel notch here and a series notch and your are pretty much done. It's a great DIY waveguide that is not hard to work with.

This is where I got mine! Go figure especially in production quantities! Look what else they have! Just by all the parts!

https://reconingspeakers.com/product/jbl-m2-horn-lens-5025594/

Rob :)
 

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Duke LeJeune

[Industry Expert]/Member Sponsor
Jul 22, 2013
189
72
28
Princeton, Texas
#30
As far as the crossover with a typical large format CD it's a parametric compensation. So a parallel notch here and a series notch and your are pretty much done. It's a great DIY waveguide that is not hard to work with.
Is that your highpass network? Verrry interesting response shaping circuit that bypasses your fixed L-pad. Nice job!!

This is where I got mine! Go figure especially in production quantities! Look what else they have! Just by all the parts!

https://reconingspeakers.com/product/jbl-m2-horn-lens-5025594/
I had NO IDEA they were available over-the-counter! Just sent an e-mail inquiry. I'll do my own crossover of course!

THANK YOU!!

Edit: Speaker Exchange doesn't get the JBL waveguide in quantity nor do they sell it in quantity, and if I were to use it in a commercial product, I would not be allowed to advertise that product. So it's practical for DIYers, but not for a small manufacturer. That's okay, I'm already moving in a different direction anyway.
 
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Robh3606

Active Member
Aug 25, 2010
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#31
Thanks! It's based on Greg Timbers "Key" crossover that he used to work out CD comps for the 9800 system. He was kind enough to share it with us. LEAP is awesome software. It makes things so much easier.

Amazing isn't it!

Rob :)
 
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Duke LeJeune

[Industry Expert]/Member Sponsor
Jul 22, 2013
189
72
28
Princeton, Texas
#32
Thanks! It's based on Greg Timbers "Key" crossover that he used to work out CD comps for the 9800 system. He was kind enough to share it with us. LEAP is awesome software. It makes things so much easier.
LEAP is what I use too.

Too bad we lost Chris Strahm.
 

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