FerroFluids
   Ferrofluid
   Magnetorheologic Suspensions
   FFS
   LiquidAudio
     Testing

Home → FerroFluids → LiquidAudio → Testing

LiquidAudio has passed through a range of complete testing procedures held by FLAB.
 
FLAB (Russian Electro-Acoustic laboratory).is a company that specializes in technical consulting and acoustics project designs. It works in the fields of Home Theater, Hi-Fi, Hi-End systems, PC Sound, Car Audio, Professional sound.
 
The company also puts into production speakers and speaker systems for Car-Audio, Pro Audio, Hi-Fi, High-End, PA systems and provides professional services of development and testing of amplifiers, drivers and acoustics systems.
 

TESTING OF FERROLABS’ FERROFLUID FLA SERIES IN A 3-INCH FULL-RANGE SPEAKER

Considerable increase of Fo (resonance) of loudspeakers and considerable decrease of Qms (mechanical Q) and minor increase of BL (magnetic flux) was common for all three types of FLA ferrofluid. At the same time loudspeaker gain-frequency characteristics practically didn’t change.
 
Table indicating change of characteristics:
    Fo Qms Qts B1 SPLo
FLA 001.13 Before 107.3 6.86 0.731 2.832 86.006
  After 133.4 1.74 0.627 2.966 85.929
  Change +24% 3.95 times < 1.66 times < insignificant insignificant
FLA 002.23 Before 110.5 6.35 0.708 2.846 86.5
  After 143.6 1.321 0.554 3.18 86.2
  Change +30% 4.8 times < 1.27 times < insignificant insignificant
FLA 003.40 Before 116.63 7.118 0.732 2.96 86.4
  After 152.6 1.95 0.668 3.1 86.4
  Change +43% 3.65 times < 1.09 times < insignificant No change

 

 
Subjective listening showed that loudspeakers sound better when low viscous and high saturation magnetization ferrofluid is used. BL increase doesn’t lead to SPL increase due to the increase of moving system mass (Mms).
 

CUMULATIVE SPECTRAL DECAY

Improvements of audio quality is partially illustrated by cumulative damping spectrum (Measurement in imperfect loudspeaker enclosure).
 

 

LIQUIDAUDIOTM IN A 1-INCH TWEETER

Ferrofluid FLA 003.40 in a 1-inch tweeter.
 
For our research work we used TB Speakers 25-669 SD loudspeaker with silk dome that is widely used in hi-end multimedia systems and Hi-Fi systems due to its high performance parameters.
 
Rz and gain-frequency characteristics were measured without ferrofluid; with originally used ferrofluid and with ferrofluid FLA 003.40.
 

 
For increased from 966 Hz up to 1086 Hz while using original ferrofluid and ferrofluid FLA 003.40 that is acceptable for the given tweeter (at permanent gain-frequency characteristics in the working range (2-25 kHz).
 
On Rz drawing for tweeter without ferrofluid one can easily notice considerable distortion for 1,8 kHz; 2,8 kHz; 4,41 kHz; 5,8 kHz; 8 kHz frequency („curves“ on Rz drawing).
 
Ferrofluids decrease the distortion but when employing FLA 003.40 mechanical Qms is considerably lower: 1.799 instead of 2.361 for original ferrofluid. It confirms that FLA 003.40 has higher damping parameters.
 
Thiele-Small parameters for tweeters without ferrofluid, with original ferrofluid and with test ferrofluids:
 
* Loudspeaker Measurement System
* LMS(TM) 4.5.0.352 Jul/01/2005
* (C)opyright 1993-2000 by LinearX Systems, Inc.
* Electro Mechanical Parameters
* Dec 25, 2006 Mon 2:31 pm
* Library=FerroFluidW3-1024S.lib
* Reference Curve=25-669SD w/o any FL Rz
* Delta M/C Curve=+2gr
* Method=Single Curve — Elec System
Domain=FreeAir
Model=TSL
Revc=5.150 Ohm
Fo=966.281 Hz
Krm=31.549u Ohm
Erm=0.928
Kxm=1.108m H
Exm=0.674
Qms=4.003
Qes=3.654
Qts=1.910
* Loudspeaker Measurement System
* LMS(TM) 4.5.0.352 Jul/01/2005
* (C)opyright 1993-2000 by LinearX Systems, Inc.
* Electro Mechanical Parameters
* Dec 25, 2006 Mon 2:30 pm
* Library=FerroFluidW3-1024S.lib
* Reference Curve=25-669SD w/o FLA/originFL Rz
* Delta M/C Curve=+2gr
* Method= Single Curve — Elec System
Domain= FreeAir
Model= TSL
Revc=5.150 Ohm
Fo=1.086K Hz
Krm=102.724u Ohm
Erm=0.831
Kxm=702.711u H
Exm=0.717
Qms=2.361
Qes=2.600
Qts=1.237
* Loudspeaker Measurement System
* LMS(TM) 4.5.0.352 Jul/01/2005
* (C)opyright 1993-2000 by LinearX Systems, Inc.
* Electro Mechanical Parameters
* Dec 25, 2006 Mon 2:32 pm
* Library=FerroFluidW3-1024S.lib
* Reference Curve=25-669SD w/o any FL Rz
* Delta M/C Curve=+2gr
* Method= Single Curve — Elec System
Domain= FreeAir
Model= TSL
Revc=5.150 Ohm
Fo=966.281 Hz
Krm=31.549u Ohm
Erm=0.928
Kxm=1.108m H
Exm=0.674
Qms=4.003
Qes=3.654
Qts=1.910

 

CONCLUSIONS

Preliminary results show that application of low viscous and high saturation magnetization ferrofluid in full-range speakers and tweeters is promising and needs further investigation.
© 2004-2016 Ferrolabs, Inc.
All rights reserved.
Presentations  |  Privacy Policy  |  Contact our manager