mass ring or not

[ditusa]

what are anyones thoughts regarding jbl 4435 studio monitors and mass rings? prefer with or without? which way sounds best?

[1audiohack]

Hi ditusa;

Welcome to Lansing Heritage.

My opinion, for sure no mass ring in the woofer under the horn.

When I replaced the surrounds on my 4435’s I loaded them with 2235’s for the week the 2234’s were out, I wouldn’t do that permanently. I have thought about putting a ring in the helper woofer as an experiment but never have.

I ran my 4430’s both ways and preferred them without the mass ring and a touch of LF EQ bump.

Are you rebuilding a pair of 4435’s or?

Barry.

[Horn Fanatic]

what are anyones thoughts regarding jbl 4435 studio monitors and mass rings? prefer with or without? which way sounds best?

Greetings -

The mass ring serves to increase the total mechanical mass of the cone assembly, thereby lowering the free air resonance ( fs ) of the woofer. By removing the ring you essentially have your speaker in an enclosure that is not tuned to the speaker. The difference in fs between having the ring or not, could be as much as 20 Hz.
JBL saw fit to use the ring to lower the fs rather than using a heavy cone. Another trick JBL used to lower the FS would be the difference between the D123 and 123A, was buy coating the 123A with that white crap.

Does removing the mass ring make the speaker sound better? The question should be; Does a misaligned speaker enclosure sound good?

Just sayin'...

HF

[1audiohack]

Hello HF;

In my experience the addition of the mass rings drops the fs of a 2234 between three and four Hz and reduces the midband efficiency just under 3dB. I reconed a large batch of them and measured fs and Z of them all without and then with the mass ring.

You are correct of course that it will unbalance a well engineered speaker like a 4430 or 4435. The reduction in midband is most notable.

Barry.

[Horn Fanatic]

Hello HF;

In my experience the addition of the mass rings drops the fs of a 2234 between three and four Hz and reduces the midband efficiency just under 3dB.

Barry.

Hi Barry -

I stand corrected. I should have explained myself better. However, I'm not all that familiar with the 2234. I conducted a T-S parameter test about ten years ago with one of my 136A's after the mass ring dislodged and fell out through a separation between the dome and the cone, and compared it to it's mate. The fs was appreciably different without the ring. Not having the ring changed the mechanical mass reactance which changed the fs. In turn changing the mechanical impedance.

Thanks for your input.

HF

[F_430]

Greetings -

The mass ring serves to increase the total mechanical mass of the cone assembly, thereby lowering the free air resonance ( fs ) of the woofer. By removing the ring you essentially have your speaker in an enclosure that is not tuned to the speaker. The difference in fs between having the ring or not, could be as much as 20 Hz.
JBL saw fit to use the ring to lower the fs rather than using a heavy cone. Another trick JBL used to lower the FS would be the difference between the D123 and 123A, was buy coating the 123A with that white crap.

Does removing the mass ring make the speaker sound better? The question should be; Does a misaligned speaker enclosure sound good?

Just sayin'...

HF

(accidently used wrong quote.)
I am considering a dual 15 enclosure, and found this discussion.
Mix 2234 & 2235H in one enclosure, or 2 2234H's.
Without the luxury of testing, can someone with the tech background give an opinion or comment on this?

[macaroonie]

Without going into the technical aspects of the 2234 vs 2235 I can tell you from my own experience that the mass ring adversly affects the mid band performance at the typical hand over @800Hz.
I have 2235's unmolested since new in home brew active 3 way boxes.
when I built them I had a good idea that the MF would be compromised so the horn and driver were chosen with 500Hz capability (2380 + B&C DE85 ( with a touch of magic dust ))
I started out at 800Hz but it was quite clear that there was a muddyness in the midband. After a few weeks this began to annoy and the LF/MF handover gradually drifted down and settled at about 625 Hz. below that by much it started to get horn honky.
This is exactly what I had experienced with the 4430 when I was a dealer but of course with the smaller HF assembly you don't have the option of going lower.
So I'm with Barry , 2234 x2 and add bump du jour with eq.

M

[Robh3606]

So I'm with Barry , 2234 x2 and add bump du jour with eq.


There is no reason to use EQ just go 2 1/2 way like the 4435 or Everest.

Rob:)

[macaroonie]

Fair point Robb. Are the 4435 split chambers for the LF drivers . ( can't remember )

[Robh3606]

Are the 4435 split chambers for the LF drivers . ( can't remember )

Hello Macaroonie

Good question neither can I!? Everest is single I think 4435 is also?

Rob:)

[macaroonie]

http://jblproservice.com/pdf/Studio%20Monitor%20Series/4435LR.pdf

Shows 2 x 2234 and no apparent dividing panel. The x/o is pretty complex for LF , bleeds in the helper driver. Who knows whats happening when it is not running ?
Does it just blow about in the wind. I'm sure the designers covered the bases.
Hmmmm.

[1audiohack]

No dividers in the 4350, 4435 or the DD66000-67000’s.

The helper woofer is still connected to an amp, LF signal or not. By the time you get to 100Hz there wont be much movement to modulate the helper woofer even if it were not dampened by an amp.

I like the “helper woofer” (there has to be a better descriptor!) Done right it’s an elegant solution.

Barry.

[Mr. Widget]

I like the “helper woofer” (there has to be a better descriptor!) Done right it’s an elegant solution.How about AARP?

Actively Augmented Radiator Pair


Widget

[Kay Pirinha]

Hello,

according to the cabinet drawings in this thread (http://www.audioheritage.org/vbulletin/showthread.php?2355-4435-Diy&highlight=DIY%204435) there are two separate chambers in the 4435. For details, have a look at this drawing (http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=2539&d=1084455870).

Best regards!

[Ian Mackenzie]

That’s someone’s interpretation of the construction.

On basis of both woofers functioning below 100 hertz it really makes no difference to the drivers.

But the acoustic output of both drivers sums to provide a flat response below 100 hertz.

A single 2234 has a drooping response below 100 hertz. That’s the way it’s designed and it works very well. The 4435 is more dynamic than the 4430 and the woofers have more definition in the midrange. That’s common knowledge in the recording industry.

They are designed for suspension over head and inverted so the horn is at the bottom in a control room. It’s quite a respectable loudspeaker given the vintage.

[Kay Pirinha]

Ok. As Hofmannhp was a Super Moderator then, I've regarded his work as absolutely trustworthy. Admittedly I never had a look into an empty 4435 cabinet, though ;). To be more precisely, I never had the chance to look at and listen to a pair of 4435's :(.

Best regards!