What about ferrofluid ?

[andychris]

Hello
I would like to know the advance of ferrofluid in hifi use for JBL 2" drivers. Have you heard a difference ? I've got a pair of 2450.

Thanx

[martin2395]

Hello
I would like to know the advance of ferrofluid in hifi use for JBL 2" drivers. Have you heard a difference ? I've got a pair of 2450.

Thanx

I think that Meyer Sound did use ferrofluid in their version of the 2450:
http://www.audioheritage.org/vbullet...d-ms-2001-a%29

Have you managed to clean your 2450's? I'd give them a check to see if they are still up to spec before doing any mods.

[ivica]

Hello
I would like to know the advance of ferrofluid in hifi use for JBL 2" drivers. Have you heard a difference ? I've got a pair of 2450.

Thanx

Hi andychris,

I have no experience with JBL Be Diaphragm ( used in 476 driver), neither Mg,
unfortunately, only with JBL-AL, JBL-Ti, JBL-Ti/ribbed, JBL-Ti-SL, Radian-AL and Truexten-Be.

Any of the mentioned are quite OK up to 10kHz, but over 10kHz their behavior become "unstable"
I would not expect that ferrous-fluid would reduce the diaphragm"unstable" oscillations over 10kHz.

JBL SL (coated) Ti or Be diaphragms have shown less resonance tendency then "clean" Ti.
My experience with JBL-AL diaphragm is that it can "go" till to 20kHz with "acceptable" FR deviations if You do not plan to use UHF driver.
I believe that JBL-Be (SL) diaphragm ( used in 476 driver) would behave very good too.
Applicable horn would make an influence too.
Either of the mentioned including Radian and Truextent can be used up to (say) 8~10kHz, so UHF driver has to be applied.

Regards
Ivica

[cooky1257]

I use a 2452 with Truextent Be on a H9800 horn and have good results out to 15khz and find I don't miss UHF driver.

Hi andychris,

I have no experience with JBL Be Diaphragm ( used in 476 driver), neither Mg,
unfortunately, only with JBL-AL, JBL-Ti, JBL-Ti/ribbed, JBL-Ti-SL, Radian-AL and Truexten-Be.

Any of the mentioned are quite OK up to 10kHz, but over 10kHz their behavior become "unstable"
I would not expect that ferrous-fluid would reduce the diaphragm"unstable" oscillations over 10kHz.

JBL SL (coated) Ti or Be diaphragms have shown less resonance tendency then "clean" Ti.
My experience with JBL-AL diaphragm is that it can "go" till to 20kHz with "acceptable" FR deviations if You do not plan to use UHF driver.
I believe that JBL-Be (SL) diaphragm ( used in 476 driver) would behave very good too.
Applicable horn would make an influence too.
Either of the mentioned including Radian and Truextent can be used up to (say) 8~10kHz, so UHF driver has to be applied.

Regards
Ivica

[Lee in Montreal]

Isn't ferrofluid's only purpose for cooling? I don't know if it has any sound enhancing capabilities.

It is also known to thicken and harden over time. And it's a bad thing. ;-)

[ivica]

I use a 2452 with Truextent Be on a H9800 horn and have good results out to 15khz and find I don't miss UHF driver.

Hi cooky1257,

It would be nice if You can show us 'high-resolution' measurements of 2452&Trex-Be with H9800.
My measurements have shown that over 12kHz ( 2450-1.5 driver with Trex-Be and JBL-2332 horn) a kind of 'irregularities' become quite visible.

regards
ivica

[cooky1257]

Probably not what you are after but best I can do, in room response at about 2m , mic pointing upwards but on axis with horn(very very loud!)Mini dsp umic/REW.

[ivica]

Probably not what you are after but best I can do, in room response at about 2m , mic pointing upwards but on axis with horn(very very loud!)Mini dsp umic/REW.

Hi cooky1257,

Many thanks for the data You have shown us.
regards
ivica

[pos]

Hello
I would like to know the advance of ferrofluid in hifi use for JBL 2" drivers. Have you heard a difference ? I've got a pair of 2450.

Thanx

I saw measurements and reports about how ferrofluid was able to tame the heavy breakups of the ribbed Ti Dome (the two peaks around 12k and 17k).
I don't exactly understand how this is possible, as the VC should not be sufficiently affected by those breakups modes, but it seems to be the case anyway

[cooky1257]

I should point out that curve I posted is an in room response(look at the bass!)post dsp, the falling response is deliberate and eq'd to roll off at about 14.5khz.