JBL 4 Way Build Questions

[pennysdad]

Why so high with your bass/Lo-mid x-o point?
Those 2123's are good right down to 80Hz, not that I'm suggesting you go that low, but I reckon you'd be happier keeping bass doing just bass. Yes? No?
ps: JBL recommend 300Hz, but that's only because all of their boxes only had 1x12" mid so it was a 'power thing', but they would've lowered it if it had 2.
In the end, I bet you'll wish you had doubled up on the 15". LOL.

Lovely job tho'.

 

[pennysdad]

Parallel always performs better. With a series connection, your damping factor goes to hell in a handbasket. What you listen to is not real with a series speaker connection.

If I had two tweeters a side, I'd run them in series. Much less costly to fix when something goes wrong.
You'll generally only lose two out of the four.

 

[Mohawk]

Why so high with your bass/Lo-mid x-o point?
Those 2123's are good right down to 80Hz, not that I'm suggesting you go that low, but I reckon you'd be happier keeping bass doing just bass. Yes? No?
ps: JBL recommend 300Hz, but that's only because all of their boxes only had 1x12" mid so it was a 'power thing', but they would've lowered it if it had 2.
In the end, I bet you'll wish you had doubled up on the 15". LOL.

Lovely job tho'.

I'm gonna' try that indeed !

The specs say "Usable frequency response shall extend from 80 Hz to 6 kHz."

But looking at the fq response I thought I would start around 300

Double 15's you say ?

The wife already thinks I'm nuts....

I do have a set of 2241 18's ..... Soooo many options !



Cheers !

 

[pennysdad]

Oh noooooo..... Not the 2241's?????? Yeh!!!! Bring it on. Your wife will love you long time. heh heh heh....
I've got 4x 2215 and a 2235 and 2x 18" Turbosound thingies. All running. Even at the quietest moments it's just bliss.
That 2.5dB dip if you x-ed at even 200Hz, will save you pulling it out on your x-o or GEQ.
You really should bi-amp with an active x-o. Then you can tailor it however and whenever you like simply at the twist of a knob...

 

[Mohawk]

Bi-amp you say ?

No way ..... How bout' quad amp setup and a Minidsp 4x10 active crossover / DSP





The 700 and one 400 are full WOPL . Gonna have to get Joe to send me some goodies to build out the other 400 and one more 400 that's on the bench patiently waiting to replace that crown amp....

Love this hobby !

M

 

[pennysdad]

Well, yeh, but ya gotta learn to crawl before you can fly!

 

[pennysdad]

Bi-amp you say ?

No way ..... How bout' quad amp setup and a Minidsp 4x10 active crossover / DSP

View attachment 63733 View attachment 63734 View attachment 63735 View attachment 63736 View attachment 63737

View attachment 63739 View attachment 63740

The 700 and one 400 are full WOPL . Gonna have to get Joe to send me some goodies to build out the other 400 and one more 400 that's on the bench patiently waiting to replace that crown amp....

Love this hobby !

M

That's just so killer!
Luv it.
Wot is it?
How much is it?
Can I get it for a Mac?

 

[Mohawk]

Maybe I'll add the 2241's for sub duty and use the 15's as mids !
As it is now the top of the tweeter is at about 5 ft

The Wife claims " I'm pushing it " !!!

M

 

[Gepetto]

Maybe I'll add the 2241's for sub duty and use the 15's as mids !
As it is now the top of the tweeter is at about 5 ft

The Wife claims " I'm pushing it " !!!

M

Go big or go home

 

[krellmk]

Maybe I'll add the 2241's for sub duty and use the 15's as mids !
As it is now the top of the tweeter is at about 5 ft

The Wife claims " I'm pushing it " !!!

M

Welcome to the club my wife wife told me the thing
" I'm pushing it " !!!

when i start bringing home these monster amplifiers .. she didn't know i had a Flutterman behind the sofa untill one of the grand kids Woodie the cowboy fell behind the sofa

 

[udo]

Hello Mohawk,
Take a look at Rephase as you are using a Mini DSP unit to control/cross your speakers. https://rephase.org/
They have a technote about using FIR in Mini DSP products. And in the past we did a thing with JBL what was called the Marquis series for dance clubs.
MD1, MD2, MD3 and MD7. For the mids we used a double 8 inch with a common chamber that was coupled with a horn. The whole system was horn coupled. So FIR was almost the only way to go for it.
Have fun.

 

[udo]

Bi-amp you say ?

No way ..... How bout' quad amp setup and a Minidsp 4x10 active crossover / DSP

View attachment 63733 View attachment 63734 View attachment 63735 View attachment 63736 View attachment 63737

View attachment 63739 View attachment 63740

The 700 and one 400 are full WOPL . Gonna have to get Joe to send me some goodies to build out the other 400 and one more 400 that's on the bench patiently waiting to replace that crown amp....

Love this hobby !

M

Hi Mohawk,
Do you use some measuring equipment for you timing /frequency/phase response to determine your crossovers? I'm using SMAART 8 .
But you can find quite cheap software to do that job too. This is one of them EASERA-SysTune . Hope it helps.
Udo.

 

[Gibsonian]

Late to this thread but sure looks good Mohawk. Parallel, for sure, cross at 300 or above, for sure. Plenty of headroom with two of them per side, 104 dB on paper efficiency. Guessing it will sound quite nice. I have a pair of these I was saving for a project, how easy was the recone?

 

[Mohawk]

A re-cone itself is very straightforward... The issue is being carful with the adhesives !

I chose the JBL original one piece kits, the voice coil / spider are assembled so really the big issue is the dust cap and glue....

Once the frame is clean, clean it again and once more just to be ... clean.... A folded piece of masking tape down into the magnet grove picks up some little bits that are hiding in there ...

I sat the frame on an old turntable so I could rotate the speaker... Don't think yer' gonna get a nice bead of glue by moving your hand in a prefect circle. Keep your hand still ( ish) and spin the frame ....

Use a plastic bottle for the glue... Avoid the metal "toothpast" type ... The plastic squeeze bottle is far more consistent for flow !


https://www.simplyspeakers.com/speaker-repair-adhesive-mi-2000.html



All about the prep and a steady hand !

 

[e30m3mon]

The latter being the challenge for me, I learned! No chance of me becoming a surgeon LOL!

 

[Gibsonian]

A re-cone itself is very straightforward... The issue is being carful with the adhesives !

I chose the JBL original one piece kits, the voice coil / spider are assembled so really the big issue is the dust cap and glue....

Once the frame is clean, clean it again and once more just to be ... clean.... A folded piece of masking tape down into the magnet grove picks up some little bits that are hiding in there ...

I sat the frame on an old turntable so I could rotate the speaker... Don't think yer' gonna get a nice bead of glue by moving your hand in a prefect circle. Keep your hand still ( ish) and spin the frame ....

Use a plastic bottle for the glue... Avoid the metal "toothpast" type ... The plastic squeeze bottle is far more consistent for flow !


https://www.simplyspeakers.com/speaker-repair-adhesive-mi-2000.html

View attachment 73532

All about the prep and a steady hand !

Ok, doesn't sound too bad. I've refoamed many, so seems it would be not alot different for me to do.