KS-263

IMG_0871.JPG

Introduction
Prototypes
Enclosure
Crossover
Simulations
Measurements
Sound
Summary


Introduction

Originally these speakers didn't have any special mission or place to locate. They were just a trip to the golden/dark 80s' when speakers were usually big and ugly rock n' roll boxes. Big part of modern fashion furnitures - locally called as controlled directive speakers - may sound inappropriate. Especially with older recordings listener easily focuses everything else expect the music. 3-Way Classic of Troels Gravesen was excellent starting point for retro speakers. Same mid-range driver was found in the storage. CD22RN4X and HDS-1" were close enough. CD22RN4X is heavier low-bass driver than CA22 which was kind a risk.

Technical specifications

General 3-way, vented, mid closed
Dimensions 300 x 540 x 280 mm (W x H x D)
Volume 23 + 3.5 liters
Tuning 37 Hz, vents 2 pcs Ø50 x 270 mm,
inner ends 45º
X/O frequencies 400 Hz and 3200 Hz
Sensitivity 83 dB/2.83V/1m (estimated)
Drivers Peerless 810921 (HDS-1")
Seas MCA12RC
Seas CD22RN4X
Impedance 8 ohm, min. 5.0 ohm @ 105 Hz


Prototypes

None.


Enclosure

Material is 25 mm MDF board, except internal mid box which is 19 mm.

Enclosure drawing: KS-263.pdf

Img_0400.jpg Img_0404.jpg Img_0407.jpg Img_0411.jpg Img_0410.jpg Img_0418.jpg

Crossover

Filter schematic, version 5:
KS-263_XO_v5.PNG

C1021 = 82 + 10 uF or 56 + 27 + 8.2 uF
R2011 = 1.2 ohm + inductor's 0.53 ohm
R2041 = 3.9 ohm + inductor's 0.30 ohm
R3011 = 4.7 + 1.5 ohm
R3041 = 6.8 ohm + inductor's 0.27 ohm

Components from Graditech, except 3.9 mH Intertechnik Corobar.

Img_0425.jpg

Components are on a plastic chopping board, 170 x 245 mm (version 1).


Simulations

Filter version 5.

Frequency response

Drivers measured at 50 cm on-axis
- vent signal is not included, causing dip at low end (actual -6 dB @ 35 Hz)
KS-263_FR_simu.png

Filter response

Woofer
KS-263_Net-1_Gain_simu.png

Mid-range
KS-263_Net-1_Gain_simu.png

Tweeter
KS-263_Net-3_Gain_simu.png

Phase response

KS-263_PR_simu.png

Impedance response

KS-263_ZR_simu.png

Measurements

Frequency response

KS-263 frequency response
- above 450 Hz: at 50 cm on-axis, time window 10 ms, smoothing 1/6 oct.
- below 450 Hz: ground plane measurement, time window 185 ms
- crossover version 3
- left
KS-263_FR_50cm_0deg_185+10ms_1p6okt_mrg-450Hz.png

- right
KS-263_FR_50cm_0deg_185+10ms_1p6okt_mrg-440Hz.png

Frequency response at 75 cm 0-90º horizontal angles, increment 15º:
- time window 10+100 ms, smoothing 1/6 oct.
- right speaker, angles to left (in)
KS-263_FR_75cm_0-90deg-in_100+10ms_1p6okt.png

- right speaker, angles to right (out)
KS-263_FR_75cm_0-90deg-out_100+10ms_1p6okt.png

CD22RN4X at 100 cm on-axis
- time window 185 ms, smoothing 1/6 oct.
CD22RN4X_FR_100cm-GND_00deg_185ms_1p6okt.png

CD22RN4X, sum of near field responses (black)
- vent signals are attenuated 12 dB (theoretical value is -11.3 dB)
CD22RN4X+vents_FR_near_185ms_1p24okt.png

MCA12RC at 50 cm on-axis
- time window 20 ms, smoothing 1/12 oct.
MCA12RC_FR_50cm_00deg_020ms_1p12okt.png

810921 at 50 cm on-axis
- time window 10 ms, smoothing 1/24 oct.
810921_FR_50cm_00deg_010ms_1p24okt.png

Step response

100 cm on-axis:
KS-263v4_SR_100cm_0deg.png

Impedance response

CD22RN4X in vented enclosure
- actual tuning is 37 Hz
CD22RN4X_ZR_vent-50x270mm-45deg.png

MCA12RC
MCA12RC_ZR.png

810921
810921_ZR.png


Sound

Speakers are quite neutral and fit very good for listening out of the spot. Sound is open across the room because of small (wide angle) mid-range. They handle different genres, and also lower quality recordings very polite.

Details and nuances are clear when listening distance is less than 2.5 m. Resolution drops over longer distances, which is normal behavior without strong directivity.

Sound pressure capacity is not bad at all. Mid-range stays clean even high-pass is only 1st order.

Bass is closer to soft and full-bodied than fast kicker. It's not slow or sloppy however. There's no booming, i.e. relatively small enclosure won't resonate too much. Tracing of bass notes is normal for this kind of speaker; can be good or bad, depending on setup and room properties. Treble is really good - maybe better than Seas tweeters I've owned.

Timing, i.e. strength of piano and percussion is surprisingly good even the speaker is 3-way. Probably lower X/O frequency is high enough and slopes are not too steep.

Sound stage may be more transparent and deep when speakers are aimed slightly in front of the listener. M+T is better to be on inner edge of front baffle. Images may disintegrate when M+T is on outer edge. Also vents on inner side may improve stereophonic illusion, which is surprisingly strong when setup (placements) is carefully adjusted.

Placement on a massive wall to avoid loss of mid-bass. Distance from front baffle to front wall about 50 cm. From tweeter to tweeter 200...210 cm. Listening distance 220 cm. Speakers aimed towards listener, or slightly in. Stands 60 cm.


Summary

This project was a success. Retro look but sound is also hifi - not only rock n' roll.

Page updated 11.10.2010

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