Kairos 3-way cabinet

I have built the Kairos Three Way using the SB Acoustics SB29NRX75-6 ten inch woofer and the recommended crossover from Meniscus.
In my opinion this crossover design does not match that woofer.It might be fine with a 4 ohm woofer but the SB Acoustics is a 6 ohm and simply sounds wrong.Changing from a 4 ohm to 6 ohm driver surely must change the crossover points significantly-well technically it does anyway.
There seems to be a lot of overlap in the mid/upper bass area between about 110Hz and 250 Hz.This is mentioned in the white paper but I really think it sounds a lot more obvious than the measurements would appear to indicate and the excellent sound qualities of the two way module are spoiled by this overlap.


I think I have largely fixed this problem by some quite simple modifications to the crossover but would be reluctant to post these changes here as they may be technically imperfect -but the sound is MUCH better to my ears [and anyone else who has heard the difference].
 
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I left the woofer crossover as it was except for removing the 3 ohm resistor..You could try a 75 -100 uF capacitor on the high pass crossover to the two way instead of the 150uF in conjuction with removing the 10 ohm resistors.That sounds radical because those resistors must be there for a good technical reason [damping resistors] but they seem to also damp the life and vibrancy out of the speaker.As I said this might be technically imperfect but to me sounds a lot better.
What sounds best may also be impacted by which inductor is used in the two way section,Mine is the basic laminated core so probably has less insertion loss than the air core alternative.
Also try a bit lower value resistor in place of the 6.2 ohm on the tweeter.My Kairos sounded a bit dull but that could also be due to the inductor on the mid .
 
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Another update.
If you are using the SB Acoustics 29NRX woofer I think it pays to change the inductor on the low pass to something like 7.5 mH rather than the 5mh specified.That is more in keeping with a 6 ohm speaker crossover.I used a 7.8mH because that is what I had.In the Parts Express forum a crossover for this was woofer in a Kairos type 3 way was specified to use a 7.5uF inductor and a 200uF cap- just to confirm my experiments-.Wish I had have known that before! Getting the sound sorted was driving me nuts!
And to contradict myself in the above posts leave the 150uF caps as they are and also use the 10R resistor parallel resistor.-they are fine like that once you correct the woofer crossover point [make it lower] by increasing the inductor value there.[getting rid of the obvious overlap].
I still prefer it with the 3 ohm resistor on the low pass removed.


It sounds very good.Just have to make a better bass cabinet.
 
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Linesource, I love the design. How does this speaker sound?
Any measurements?


Par

The rectangular cabinet volume is a standard, well braced box like Troels vertical beveled-baffle Ekta Grande, or stepped-baffle Ekta mk2. Use a 2"-2.2" thick (3*0.75") stacked baffle which allows deep top+side edge bevel cuts as used by Avalon, and the Hulgich Ella_mk2 example with dimensions H45” W13” D17”

Use the attached crossover schematic component values. I made a couple changes from earlier ckts to both smooth the baffle step compensation for a modest volume room, and to select common values for the large 5mH-7mH inductors from Erse / Sledgehammer. Metalized film capacitors like the 400V Audyn family can be used. The C1=140uF midrange capacitor in the schematic should be built from one 100uf cap and two 20uF capacitors in parallel, because you may favor C1=120uF for slightly less midbass gain if the speakers are near the wall. The C8=150uF woofer capacitor can be a low cost bennic-bipolar, or built from 2-3 metalized film capacitors like the 400V Audyn family if cost is not an issue.
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If you decide to use a passive crossover, the modest efficiency of the single WO24P-8 woofer, especially after baffle step correction SPL reductions, requires attenuation of the midrange(ckt diagram). This can lead to selection of the lower efficiency MW13P-8 midbass with Xmax=5mm and lower sealed box -F3 frequency instead of the MR13P-8 with Xmax=3mm. Passive crossovers often favor lower component count circuits with larger Xmax demands from the modest slopes.

If you decide to use an active crossover with one amplifier per driver and steeper crossover slopes, you can consider the MR13P-8 with lower Le and Mms.
 
Hi! I’m getting the parts to build the Kairos 2-way, but have an opportunity to pick up some used Satori WO24-8 woofers.

Would a pair of the WO24-8 in sealed cabinets as stands for the Kairos work well to extend the bass? Should I purchase two pairs and wire them in parallel? I have a miniDSP for now and could eventually try and workout a passive crossover for them.

Thanks for your advice!
 
Would a pair of the WO24-8 in sealed cabinets as stands for the Kairos work well to extend the bass?

The WO24P is a medium power capacity woofer:
_Effective piston area Sd = 255 cm2
_Sensitivity (2.83 V / 1 m) = 88 dB
_Linear coil travel (p-p) = 17 mm
_Rated power handling = 90 W

If you have a small-modest volume room, one sealed 90W WO24P with a dsp (30Hz Linkwitz transform requires 2x Apparent power) and a powerful amp should satisfy most listeners.
Two 90W WO24P with a minidsp (30Hz Linkwitz transform requires 2x Apparent power) and powerful amp would deliver effortless bass even in a large room.

If you want to experiment with the Kairos time-phase coherent crossover, a crude option is to build a straight/flat baffle Aldephos TM cabinet and add a 14-degree front wedge on top of the woofer cabinet to tilt the TM top cabinet. You can experiment with different tilts for different listening distances. You can experiment with a flat baffle crossover circuit like the Adelphos for comparison.
 

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Thanks for your input Linesource!

I’ve got a few more questions...

1. To time align the woofers with the Kairos I was tossing up exactly these options! Thanks for saving me the effort of working out the measurements! I’m still wondering however, where is the optimal point to align the driver. Is it the base of the cone? Or midpoint of the front-to-back measurement of the cone?

2. Also, I realise that using DSP I should be able to integrate the woofers to make a three way speaker, but would these drivers be suitable in terms of sensitivity and other specs for eventually making a passive crossover with the Kairos? I currently know nothing about passive crossovers, but that’s a project for the future.

3. Should I even bother with this? If the sealed Kairos reaches down to approximately 50Hz, should I instead build multiple mono subwoofers rather than stereo woofer modules.

4. If I plan to bevel the front baffle to reduce diffraction, is there any issue with doubling the thickness of the panel? As long as I adequately chamfer out space behind the drivers? I’m worried about the bevel reducing the rigidity of the front baffle toward the edges.

Thanks for the help! :)
 
I’ve got a few more questions...

1) The optimal time alignment requires a simple measurement. Send a (+) phase sine wave near the crossover frequency to one speaker and a (-) phase sine wave to the other speaker and move one forward-back until a null is heard/ measured.

2) For each 3-way speaker, how many dsp channels and how many amplifiers will you have?

With 3-dsp and 3-amps you can time align and equalize each of the 3-speakers(ranges). Build a flat baffle cabinet with large edge rounds(bevels).
With 2-dsp and 2-amps you can time align and equalize the woofer, and use the second amp to simplify the passive midrange crossover -BUT- you will need either the time+phase corrected Kairos passive crossover circuits with a 13-degree slanted baffle, or the Aldephos crossover circuits with a flat/vertical baffle.

3) There are benefits to building a pair of high quality 3-ways with -F3 ~30Hz to generate an optimal stereo soundstage. Later, you have the option of building and locating one or two subwoofer where it both smooths bass room modes and generates 20-40Hz deep bass.

a) Stereo bass down to 20Hz has been produced in low distortion, high SPL since 1982 on CDs, DVD-As, SACDs, and 5.1 movies.
b) Most people with normal hearing can identify the difference between stereo vs. mono bass. Stereo bass has phase for location.
c) At frequencies below 80Hz most people with normal hearing cannot isolate the physical location of the woofer.
-----Expert listeners can isolate location of woofers down to 60Hz by focusing on impact harmonics, port noise, upper harmonic distortion.
d) Not being able to locate the subwoofer is a good cost simplification, but summing low bass into mono degrades true stereo recordings.
e) With stereo woofers & subwoofers, any out-of-phase bass information in a true stereo (acoustic) recording is reproduced properly at full level, adding immensely to the perceived width and depth of the room in which the recording was made.

4) A double thick baffle is often used with edge round/bevels are cut. As long as you adequately chamfer out space behind the drivers
 
1) Now you know that putting the Kairos / Aldephos using their recommended 200Hz crossover on top of stereo SB2000 subwoofers will not produce good sound.

2) Using stereo SB2000 subwoofers requires main front stereo speakers with -F3 below ~80Hz to meet the quarter wavelength C-to-C goal, and ideally -F3 below ~60Hz.

3) A sealed 12" SB34NRX75-6 woofer generates -F3 below 37Hz with excellent Qtc=0.7 transients before room gain effects. Adding equalization/DSP to a sealed SB34NRX75-6 with Fs=18Hz can generate -F3 ~20Hz deep bass. .... front stereo bass. SB2000 subwoofers along the rear wall or side walls can be used to smooth room bass modes at the listener.

4) The ported EKTA mk2 with -F3 = 37 Hz will also blend well with SB2000 subwoofers.

DEBATE POINT: Spend your limited floor space and money on an exceptional stereo pair of front 3-way FULL RANGE speakers.
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PORTS SUCK! they also blow...whistle...huff and puff....leak midrange harmonics

A 12" woofer like the SB34NRX75-6 designed for excellent transients in a sealed box volume can produce better sound quality than a ported alignment, but requires a larger volume box than a ported alignment for the same -F3. For the best stereo soundstage, spend your floor space and money on a stereo pair of tall front 3-way FULL RANGE speakers. Use the equalizer capability in your Denon or PC to help smooth low frequency bass.

Simplify the conversion to DSP. One of the big sonic benefits from DSP is the ease of getting very high quality bass from putting a "larger than normal" woofer in a modest volume sealed box and using a Linkwitz Transform function to get deep bass with a high power amplifier. Geddes: “The mains should be designed for the best possible direct field with as flat a power response as possible. Room equalization of the mains could only make them worse.” Initially put your single subwoofer along the rear wall(corner) to help equalize room bass modes at the listener.

You can get help to add the 12" sealed SB34NRX75-6 to the Jeff Bagby Adelphos pre-built crossover instead of the ported 10" SB29NRX75-6. You can get help on new crossover designs, if you can get local construction help.

Hello LineSource, i’m very interested in this plan of yours.
I’m looking for a 3 way sealed box with big woofer. My other option is Zaph Audio 12.3, but i think your plan is more simple and cost effective. My room is 6x8m with many opening to another rooms. I have some questions for you
1. What is the best volume for the sb34 if i want a sealed box and i don’t have to worry about place?
2. Can i use the xover plan you have in the picture as it is?
3. You have 2 options with the woofer on the front and the other on the side, what is the advantages and disadvantages of both system?

Thank you
 
Hello LineSource, i’m very interested in this plan of yours.
I’m looking for a 3 way sealed box with big woofer.

Thank you

Depending on whether you have deep pockets, the Scanspeak 23W4557T00 looks ideal for a sealed box woofer. In a 1cuft (28l) it looks like it will do 32hz f3 and 20hz f10 and can be crossed as high a 400hz (starts to break up around 800hz). This is similar performance to the SB34 but that needs a 100l box. Only thing to look at is sensitivity, the 22W looks like about 82dB/W/m, the SB34 is quoted at 90dB/W/m so the scanspeak will need more power for the same volume and may not work with the passive crossover due to difference in sensitivity with the mid/tweeter but if you are going active then not such a problem.

Worth downloading WinISD and having a ply, you can then check cone extension.

ScanSpeak Revelator 23W/4557T-02, 9" Aluminum Cone Subwoofer, Black Cone

SB Acoustics SB34NRX75-6 12" Woofer
 
Depending on whether you have deep pockets, the Scanspeak 23W4557T00 looks ideal for a sealed box woofer. In a 1cuft (28l) it looks like it will do 32hz f3 and 20hz f10 and can be crossed as high a 400hz (starts to break up around 800hz). This is similar performance to the SB34 but that needs a 100l box. Only thing to look at is sensitivity, the 22W looks like about 82dB/W/m, the SB34 is quoted at 90dB/W/m so the scanspeak will need more power for the same volume and may not work with the passive crossover due to difference in sensitivity with the mid/tweeter but if you are going active then not such a problem.

Worth downloading WinISD and having a ply, you can then check cone extension.

ScanSpeak Revelator 23W/4557T-02, 9" Aluminum Cone Subwoofer, Black Cone

SB Acoustics SB34NRX75-6 12" Woofer

Thank you for the advice, one of the reason why i choose full sb is because of the budget and for now i don’t plan to use an active xover yet, but that could be also and option. So i need about 100l for the sb to perform like the scanspeak, i think that is still very manageable
 
Hello LineSource, i’m very interested in this plan of yours.
I’m looking for a 3 way sealed box with big woofer. My other option is Zaph Audio 12.3, but i think your plan is more simple and cost effective. My room is 6x8m with many opening to another rooms. I have some questions for you
1. What is the best volume for the sb34 if i want a sealed box and i don’t have to worry about place?
2. Can i use the xover plan you have in the picture as it is?
3. You have 2 options with the woofer on the front and the other on the side, what is the advantages and disadvantages of both system?

Thank you

Hello @LineSource again, can you meybehelp me?

Thank you
 
-The SB34NRX75-6 12" woofer in a sealed 3-3.5 cuft volume can produce fast transient bass with -F3 ~35Hz.
-The Satori MR16P-4 in a Qtc~0.6 0.4cuft (tapered and stuffed) sealed volume has -F3 ~ 75Hz (Nelson Pass --> this is an exceptional sounding driver)
-With a 1.9-2kHz crossover, the modest cost SB26STCN-4 dome tweeter offers reduced C-to-C and matches the MR16P-4 efficiency
---Copy the top bevel cuts on the new Avalon Compas
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Start-up Suggestions:
1) measure your room and select the best location(s) for speaker placement and tilt-in angle to listeners.
2) use cardboard or newspaper to cut two footprints to help your cabinet selection.
a) Woofer on front baffle. H46" x W16"(frame has 13.4" diameter) x D15" 4.0cuft
b) Woofer on (left/right) side panels. H46" x W11" x D18" 3.7cuft
3) Research if your amplifier can easily drive a 3-ohm load, or if a 6-ohm load is necessary.
--Think about using all-passive crossovers, VS bi-Amping with passive TM VS tri-Amping. Isolating the woofer simplifies room compensation. If you like old-School, a good Opamp 3-way crossover ~$37 on eBay
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Post your goals and ideas
 

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Thank you @linesource,
My room is 8m x8m with many opening to another room, it’s our living room and eating room, unfortunately there is just one possible location for the speaker, around 0.5m from the wall behind, and around 3m from each side and the sofa is around 4m from the speaker. But i have no probelem with the size of the speaker.
I would like to use your plan that you propose before in this thread with the sb29rdc tweeter. Can i use the xover you put there, or do i still have to make some modifications?