KS-092

IMG_1275.JPG

Introduction
Prototypes
Enclosure
Crossover
Simulations
Measurements
Sound
Summary


Introduction

KS-092 was originally designed as surround speaker. Cheaper and worse drivers were avaiable, but it's good to have some quality if speakers will be located somewhere else.

Enclosure is wide improving immunity to front wall. Flat box with wide bevels decrease nominal frequency of baffle loss, attenuating diffractions and early refleftions at midrange. However, this is not actual wall speaker. There will be some (not full) BSC in the crossover.

Enclosure is vented with down-striking vent. This enables placement close to wall and attenuates vent resonances with floor acoustics (carpet). There will be size restriction in top plate of stands.

X/O frequency is selected according mid-woofer's break-up node (8.4 kHz) to keep 3rd harmonic below 0.5% at normal sound pressures. Attention is not paid to directivity.

Target of sound quality is not very high - not bad either.

Technical specifications

General 2-way, vented
Dimensions 260 x 390 x 180 mm (W x H x D)
Volume 8.7 liters
Tuning 44 Hz, vent Ø46/220 mm
X/O frequency 2600 Hz
Sensitivity 83 dB/2.83V/1m (estimated)
Drivers Seas 19TAFD/G, AW-120 wave guide
Seas W15CY001 (03/2000 = old)
Impedance 8 ohm, min. 5.2 ohm @ 200 Hz


Prototypes

None.


Enclosure

Material is 25 mm MDF. There are small pieces of plywood behind tweeter's screws, strengthening the connection.

Enclosure drawing: KS-092.pdf

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Enclosures are painted with roller.


Crossover

Filter schematic, version 3:

KS-092_XO_R3.gif

Resistor R1051 drops Q-value of both notches and eliminates peak between nominal frequencies. Independent resistors in the notches give close to same result, but dimensioning of resistance value is easier with common resistor. Idea has been stolen from Interview with Joachim Gerhard of Audio Physic in SpeakerBuilding.com, tip by Troels Gravesen.

IMG_3450.JPG

Components are low cost Intertechnik. Do not pay attention to differences in wire types - this wasn't any high end project. Components are clued on plastic chopping board.

Parts list

Version 3:

Resistors R P pcs
R2011 3.9 ohm metal oxide 4 W 2
R2041 12 ohm metal oxide 4 W 2
R1051 39 ohm metal oxide 4 W 2
R1021 27 ohm metal oxide 10 W 2
Capacitors C U pcs
C1061 1.0 uF MKT 160 V 2
C1041 2.7 uF MKT 160 V 2
C1061, C2011 3.3 uF MKT 160 V 4
C1041 4.7 uF MKT 160 V 2
C2031 22 uF MKT 160 V 2
Inductors L D R pcs
L1041, L1061 0.047 mH air core 0.71 mm ? 4
L2021 0.18 mH air core 0.71 mm 0.35 ohm 2
L1011 0.91 mH air core 1.4 mm 0.27 ohm 2


Simulations

Simulated frequency response, X/O version 3:
- W15CY001 100 cm, 15º, time window 10ms, smoothing 1/24 oct.
- 19TAFD/G 100 cm, 15º, time window 5 ms, smoothing 1/24 oct.
KS-092_FR-Simu_100cm_15deg_R3.gif

Simulated phase response, X/O version 3:
KS-092_PR-Simu_R3.gif

Simulated impedance response, X/O version 3:
KS-092_ZR-Simu_R3.gif

Simulated LF response with different vent lengths (in free air).
Port-simu_140+175+220mm.gif


Measurements

Impedance response

Crossover version 1
KS-092_ZR.gif

Frequency response

Distance 50 cm, 15°
- time window: adaptive filtered PIR + 300 ms
- crossover version 2
KS-092_FR_50cm_15deg_R2.gif

CSD

Same settings as previous
KS-092_CSD_50cm_15deg_R2.gif

Directivity

Distance 60 cm, 0/30/60/90/120/150/180° horizontal
- time window: adaptive filtered PIR + 300 ms
- crossover version 2
KS-092_FR_60cm_0-180deg_R2.gif

Room response

Distance 100/150 cm, 15°
- time window: adaptive filtered PIR + 300 ms
- crossover version 2
Speaker placement: 30/45/70 cm to front wall, about 95 cm to side wall
KS-092_FR_100-150cm_15deg_R2.gif

Near field response

Time window 300 ms
KS-092_W15CY001_R2.gif

Harmonic distortion

90 dB / 1 m
KS-092_THD_90dB.PNG
Empty metal stand resonates at 500 Hz (Lovan Single Tube).


Sound

Speakers are reproducing a beautiful and 3-dimensional stereophonic illusion. Sound is also natural and presence. Soundstage is sometimes better that with bigger brothers KS-009, KS-483 or KS-585, and more presence than vertically more directive KS-009 and KS-585.
Balance is neurtal and moderate clean. Treble has slight roughness but this may be a feature of tweeter + wave guide combination. It's not disruptive in my opinion.
Bass extension is good but tuning is slightly slow. 15 cm vent might be worth to try. Upper bass will be corrupted by the room reflections anyway i.e. beat won't kick so fast.
Listening range is not very wide. Higher frequencies will die when listening radically off-axis. Balance is not ok for off-spot listening in a soft acoustics.

Placement on a massive wall. 220 cm from tweeter to tweeter. Listening distance 220 cm. From front baffle to front wall 55...70 cm. Aiming 10...20° out. Stands 70 cm.


Summary

Too good speakers for the HT.

Page updated 20.10.2010

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