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Multi-Way Conventional loudspeakers with crossovers

New SB Acoustics 3 way from Troels
New SB Acoustics 3 way from Troels
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Old 23rd May 2016, 08:00 AM   #21
Bill poster is offline Bill poster  Thailand
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Originally Posted by Zvu View Post
I know of SB29NRX-75 and CSS SDX-10. What's the third option ?

I'd use it sealed too. F3=40Hz is right on the money for me.


Cabinet rather than drivers Ie ported/sealed/radiator. I noticed Jeff mentions just one PR- Wd that be enough?

How does it sound?
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Old 23rd May 2016, 08:08 AM   #22
TMM is offline TMM  Australia
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Originally Posted by jojip View Post
a bit confused about the 1.6KHz LR2. Seems really low/shallow, wont the tweeter distortions be high at loud levels?
It's pushing the limits for sure, though probably won't be objectionable until over 100dB SPL. On the SB tweeters only the 2nd order comes up below 1.5K, higher orders remain low.

Personally I would have gone for 2kHz 12db/oct or 1.5kHz 24db/oct
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Old 23rd May 2016, 08:44 AM   #23
Zvu is offline Zvu  Serbia
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Can't say without listening. JBL did something similar with Lancer L77 PR being the same SD as woofer - didn't listen to that either but i know of its existance so its been done in the past.

Somehow i get the impression that everything from SB is well engineered and of good build quality. I intentionally avoid to say value leader because someone may interpret that as being satisfied with kinda good quality at low prices. I really think that quality of their drivers is excellent. I've been listening to my SB17NRXC35/SB29RDC-C0004 for some time now and it sounds fantastic for intended frequency range (from 150Hz up in my sistem). And it is not even their flagship drivers.

The only thing that bothers me is their Satori midwoofer line. Great drivers but that notch at 1200Hz and distortion peak at the same frequency really bothers me. My concern may be unjustified but it is how it is.

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Originally Posted by Bill poster View Post
Cabinet rather than drivers Ie ported/sealed/radiator. I noticed Jeff mentions just one PR- Wd that be enough?

How does it sound?
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Last edited by Zvu; 23rd May 2016 at 09:10 AM.
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Old 23rd May 2016, 09:01 AM   #24
Bill poster is offline Bill poster  Thailand
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Default New sb acoustics 3 way from Troels

Sorry I didn't write that well, what I meant was how do they sound in your system? I'm guessing room gain helps get useful bass down to 25-30hz or so
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Old 23rd May 2016, 09:08 AM   #25
Zvu is offline Zvu  Serbia
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I have Beyma 15K200 for bass, -3dB at 40Hz. It sounds great to me and in room of about 16 sq meters. Tuned any lower and bass starts to lose control. IMHO low tuning is not desirable in small rooms - tends to mush up the bass and the rest of the sound with it.
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Old 23rd May 2016, 04:53 PM   #26
Eldam is offline Eldam  France
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Originally Posted by Bill poster View Post
Just read up on it, hadn't realized JB used this SBA 10". His design has 3 different options. Otherwise not much info on this woofer, tho he seemed to like it. Thinking to use it sealed in a design with 5.5 revs.
Is there any time alignement with Troels's version ? Or did he take simply the same cabinet shape with same numbers than J. Bagby (sam ?

WHere did you find the 5.5 revs with sealed volume please ?
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Old 23rd May 2016, 05:08 PM   #27
Bill poster is offline Bill poster  Thailand
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Default New SB Acoustics 3 way from Troels

Yes I think time aligned but the cabs look complex..don't understand why Troels kept the volume so small that the port had to be angled. Off topic but I loved his review of Munich high end, had me in stitches.

Bought the revs very cheap and still boxed..old stock Ruark (undoped) and had the wrong model number. So at a guess around 85.5db, ohm rating unknown. The SB's seem to be the right sensitivity to fill in.
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Old 23rd May 2016, 05:21 PM   #28
Eldam is offline Eldam  France
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Ah yes, found odd as well the angled port on the bass cab, why not one la Proac firering towards the floor instead ??? Could be Noisy with such 90,degree angle !!!! And after all the old rectangular ports worked better than long "tubes" !

Is there an official sealed Kairos ? Can be seen in Meniscus threads ?

Finally a MR16P-4 could be a good swap with a higher XO : 2K to 3K.... better sensivity matching too ! Ah less deep low end maybe ! (higher high pass for the mid should be needed...)

Last edited by Eldam; 23rd May 2016 at 05:36 PM.
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Old 23rd May 2016, 06:16 PM   #29
LineSource is offline LineSource  United States
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Originally Posted by Eldam View Post
Is there any time alignement with Troels's version?
For a SB29RDC+SB17NRX TM summation, SB_Acoustics measures and documents a relative time delay of 54usec for the SB17NRX, which is the equivalent of a 18mm = 0.71" physical offset (tweeter in front of midrange) in a normal room environment. Troels stepped-baffle cabinets add one 18mm thick baltic birch panel to produce this physical delay. Obvious.
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For a TW29R+MW16P TM summation, SB_Acoustics measures and documents a relative time delay of 61usec for the MW16P, which is the equivalent of a 21mm = 0.827" physical offset (tweeter in front of midrange) in a normal room environment. BUT ... Troels cabinet drawings with the 14-degree front baffle slope show a 35.6mm = 1.4" physical offset. Doh!

For a slanted baffle, an equidistant arc from the listener's ear to the acoustic center of the T and also the acoustic center of the M sets the physical offset. The challenge becomes finding the actual acoustic center of each driver. The lower the frequency, the longer the wavelengths, and the less critical the alignment is. For T-M, a 1600-1700Hz crossover design will likely time-align better on a slanted baffle than a 2-3kHz design. SO, a slanted baffle only offers perfect delay alignment at one listening distance. You can't use this model with "factory" "on-axis" measurements. You need to measure off-axis data for whatever angle you've got the drivers pointing above your head.
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Has anyone built an LR4/LR4 crossover for a flat baffle TW29R+MW16P? LR4/LR4 on a stepped flat baffle?
LR4/LR4 at 1700Hz should produce an on-axis constant directivity function from the bass baffle step frequency up to 10kHz, where the TW29R physical dome beaming dominates.

The extended high frequency coverage above 3kHz on the MW16P comes with 5db wiggles and waggles, and normal beaming effects for a 6" cone extending all the way to 10kHz. My normal TM crossover philosophy for a wide bandwidth mid(MW16P) is to use LR4/LR4 to assure at least 20db attenuation of the 3kHz+ MW16P wiggles and waggles. Wide BW midrange often fit the textbook LR4 filter. The MW16P starts to beam at 1600Hz. The TW29R has an Fs of 600Hz and is -3db ~500Hz. With proper baffle size and tweeter positioning, a textbook LR4 often works for Xovers between 1600Hz - 1800Hz. LR4/LR4 at 1700Hz for the TW29R+MW16P looks interesting....flat baffle? 21mm stepped baffle?.

If the woofer-mid crossover is set around the baffle-step frequency, an LR2/LR2 is wide enough to smear the baffle HxW step range. An M-W separation shorter than crossover/4 quarter wavelength is still important. A 42" high x 13" cabinet required for a 10" woofer experiences baffle step effects between 100-200Hz.
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Old 24th May 2016, 12:17 AM   #30
ngjockey is offline ngjockey  Canada
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Did a smaller "Wilson semi-clone" with SB15 (5") and SB26 tweeter with a powered 8" RE sub in the bass cab. Angled at 10 degrees front and back and 15 degrees on the sides. Worked out to symmetrical 3rd/3rd electrical and LR4 acoustic. So, I assume with the bigger MP16, that it would require more baffle slope. Also found that I needed a similar notch on the tweeter for a resulting peak at 4K which I attributed to the cabinet more than the tweeter.

Last edited by ngjockey; 24th May 2016 at 12:39 AM.
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