KS-132 / KS-182

Img_0397.jpg IMG_0966.JPG

Introduction
Protypes
Enclosure
Crossover
Simulations
Measurements
Sound
Summary


Introduction

Target location of this pair was either 11 m2 "quest room" or working office. Original drivers for this project were 2x Seas W12CY001 and Peerless HDS-1" or Seas 27TBCD/GB-DXT. Also enclosures were almost ready. W12 woofers were immediately sold when Hifitalo introduced their AW-3 Excel -kit, and everything was re-started.

Scan-Speak mid-woofers and Revelator tweeters were sold by another diyer from LDC6 Studio Monitor Kit. Too boomy upper bass in a small room was not satisfying. Reputation of Revelator tweeter was not entirely good. Driver could be too bright and edgy. It's also expensive - better to get work.

Vented box is selected to have more bass extension. Plasterboard walls of our house won't amplify low end too much. Volume and tuning of KS-132 were imitated from CSM by Troels Gravesen.

Technical specifications

KS-132 KS-182
General 2-way, vented =
Dimensions 210 x 480 x 210 mm (W x H x D) 250 x 405 x 294 mm (W x H x D)
Volume 12.6 liters 18.6 liters
Tuning 45 Hz, vent Ø46/145 mm 48 Hz, vent Ø65/165 mm
Intertechnik HP 70
X/O frequency 2100 Hz =
Sensitivity 84 dB/2.83V/1m (estimated) =
Drivers Scan-Speak D2905/990000 (Revelator)
Scan-Speak 18W/8545-00 (Classic)
=
Impedance 8 ohm, min. 5.2 ohm @ 215 Hz =


Prototypes

None.


Enclosure

Material is 22 mm MDF.
Enclosure drawing: KS-132.pdf, KS-182.pdf

KS-132
Img_0388.jpg Img_0391.jpg Img_0394.jpg

KS-182
IMG_0967.JPG


Crossover

Filter schematic, version 7:
KS-132_XO_v7.PNG

Red resistors are components, blanks are resistances of coils.

Parts list

version 7:
Coils

2.2 mH, air core, Cu 1.40 mm, 2 pcs
0.22 mH, air core, Cu 0.71 mm, 2 pcs

Capacitors

12 uF MKT, 2 pcs
6.8 uF, MKP, 2 pcs
15 uF, MKP, 2 pcs

Resistors

1 ohm, 5 W, 2 pcs
4.7 ohm, 5 W, 2 pcs
3.3 ohm, 5 W, 2 pcs
IMG_0963.JPG IMG_0964.JPG


Simulations

All simulations with KS-132

Frequency response

- above 300 Hz: 75 cm on-axis, time window 6 ms, smoothing 1/24 oct.
- below 300 Hz: near field measurements. Cone and vent signals are summed, vent signal attenuated 9.3 dB (10*log(Av/Sd)). Sum response corrected with calculated baffle-loss (310 Hz).
KS-132_FR_simu.png

Simulated power average ±90º horizontal blue, on-axis black
KS-132_FR_simu_avg.png

Filter response

Mid-woofer
KS-132_Net1_Gain_simu.png

Tweeter
KS-132_Net2_Gain_simu.png

Phase response

KS-132_PR_simu.png

Impedance response

KS-132_ZR_simu.png

Measurements

Frequency response

KS-182

Frequency response
- above 300 Hz: at 80 cm on-axis, time window 5 ms, smoothing 1/12 oct.
- below 300 Hz: near field measurement of woofer cone
- port signal attenuated 5.8 dB (10*log(Av/Sd))
KS-182_FR_port+near+80cm-far_0deg.png

Off-axis response
- measuring distance 80 cm
- 0-90º, steps 15º
- time window 7 ms, smoothing 1/12 oct.
KS-182_FR_80cm_0-90deg_7ms_1p12oct.png

Power average 0-360º horizontal red, on-axis green
- measuring distance 80 cm
- time window 7 ms, smoothing 1/12 oct.
KS-182_FR_80cm_0+360deg-avg_7ms_1p12oct.png

18W/8545-00

- above 300 Hz: 75 cm on-axis, time window 6 ms, smoothing 1/24 oct.
- below 300 Hz: near field measurements. Cone and vent signals are summed, vent signal attenuated 9.3 dB (10*log(Av/Sd)). Sum response corrected with calculated baffle-loss (310 Hz).
18W8545-00_FR_75cm_5deg.png

D2905/990000

- measuring distance 75 cm on-axis
- time window 6 ms, smoothing 1/24 oct.
D2905-990000_FR_75cm_5deg.png

Impedance response

18W/8545K00

vented enclosure (KS-132)
18W8545K00_ZR.png

D2905/990000

D2905-990000_ZR.png

Step response

100 cm on-axis
KS-182_SR_100cm_0deg.png

Harmonic distortion

100 dB / 1 m
KS-182_HD_100dB_1m.png


Sound

-


Summary

This project wasn't too easy and cheap. Sensitivity of one 18W/8545K00 was 3-4 dB too low. Probably magnet is bad and BL is reduced. Bad driver was revieled after speakers were fully designed, manufactured and balanced (as mono). Fortunately driver measurements were done with a good woofer - not the bad one. Woofers were changed to 18W/8545-00, which is fully compatible with K00 in practice.
Cannot recommend this design.

Page updated 09.10.2011

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