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Multi-Way Conventional loudspeakers with crossovers

pattern control below 400Hz
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Old 13th January 2019, 10:29 AM   #11
scottjoplin is offline scottjoplin  Wales
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Originally Posted by Juhazi View Post
Best practice is to just move speakers andl listening spot around the room to find best compromise with reflections and modes.
OT, but this is what I have done and would suggest for low bass if only you have to be pleased
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Old 13th January 2019, 10:34 AM   #12
hollowboy is offline hollowboy  Australia
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Say a 40" wide baffle cardioid (resistive side-vent on both sides) with each 15" at either end of the baffle and side venting. You can adjust the upper freq. pattern with how the woofers are "tilted" on the baffle relative to each other as in the Everest below:
That size and multiplicity of angles is a bit beyond me. I doubt I could fit a complex face seamlessly to the waveguide mouth.

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It does if you design it with the floor and top mounted stuff as part of the system.
I was thinking (and have begun experimenting) along those lines.

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A passive cardioid enclosure is difficult to design.
That's not good to hear. The Kimmo Saunisto site makes it seem easy.

Since I have a couple of cabinets I can cut up and try things out on, I've started chopping + measuring. So far, it doesn't look good - but it is early days yet.

If the passive cardioid thing doesn't work for me (that is: if it requires a frustrating number of trials), my fallback position is to just package a nicer version of my prototype parts into simple towers - similar layout to this Lambda Unity Tower picture (from Cowan Audio website).

To me, this looks better than an Everest style box.
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Old 13th January 2019, 08:11 PM   #13
ScottG is offline ScottG  United States
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Originally Posted by hollowboy View Post

To me, this looks better than an Everest style box.
..that's a lot more narrow.

full-on cardioid for that, and the best thread for that (with resistance) is here:

Adventures in cardioid


Note that there is another method for producing a cardioid response (or even hyper-cardioid) than acoustic leakage/resistance, and that's with 2 drivers in their own enclosures effectively "back-to-back" with the front in-phase and the rear out-of-phase (..like a dipole) but with DELAY for the front driver (..that would work well with integrating the upper-freq. horn). ..in addition to delaying the front, there is usually some "shaping" to the rear's response to get the best pattern for a specific directivity result, and of course there is the "boost" on the lower-end (..like you'll need with just about any cardioid setup). Because you are using DSP and you have extra drivers on-hand, this is probably the best method.. but it will require experimentation.
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Last edited by ScottG; 13th January 2019 at 08:19 PM.
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Old 13th January 2019, 10:44 PM   #14
frangus is offline frangus  Australia
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Originally Posted by ScottG View Post


Note that there is another method for producing a cardioid response (or even hyper-cardioid) than acoustic leakage/resistance, and that's with 2 drivers in their own enclosures effectively "back-to-back" with the front in-phase and the rear out-of-phase (..like a dipole) but with DELAY for the front driver (..that would work well with integrating the upper-freq. horn). ..in addition to delaying the front, there is usually some "shaping" to the rear's response to get the best pattern for a specific directivity result, and of course there is the "boost" on the lower-end (..like you'll need with just about any cardioid setup). Because you are using DSP and you have extra drivers on-hand, this is probably the best method.. but it will require experimentation.
Does the rear wall cause problems with the rear firing speaker? There would be a secondary bounce off the back wall just like with dipole setup?
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Old 13th January 2019, 11:28 PM   #15
hollowboy is offline hollowboy  Australia
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The Dutch and Dutch 8c speaker appears to have done passive cardioid right.

It uses a forward firing 8" that covers 100-1250Hz. The manual (and patent EP3018915A1) claims that "The passive cardioid cabinet weakens rearward radiation by over 15 dB"

The spec sheet states that the rear facing 8" drivers are crossed over at 100Hz, so it seems like they are simple subs, and do not contribute to the directivity of the forward facing driver. The manual recommends 10-80cm between walls and the rear of the cabinet.

I'd like those characteristics, but for about $15,000 less

The image is from their patent, and doesn't appear to require rocket surgery - it looks almost exactly like the boxes on the Kimmo Saunisto site.
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Old 13th January 2019, 11:36 PM   #16
mitchba is offline mitchba  Canada
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Originally Posted by hollowboy View Post
The Dutch and Dutch 8c speaker appears to have done passive cardioid right.

...
I agree. Review with measurements: Dutch & Dutch 8c Loudspeaker Review - Reviews - Audiophile Style

And, the genesis right here on diyAudio: 2-way: Waveguide + Cardioid-like
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Old 13th January 2019, 11:46 PM   #17
ScottG is offline ScottG  United States
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Originally Posted by frangus View Post
Does the rear wall cause problems with the rear firing speaker? There would be a secondary bounce off the back wall just like with dipole setup?
-it depends on the freq..

If you want it up as high as 1 kHz (including crossover region), then you should have a total width just a bit less than a foot.

Yes, some secondary out-of-phase depending on the cardioid pattern, but it should be lower in level with an appropriate crossover.. but the result won't be dipole'ish, rather it will be like a cardioid or hyper-cardioid.
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Old 13th January 2019, 11:52 PM   #18
ScottG is offline ScottG  United States
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Originally Posted by hollowboy View Post

The image is from their patent, and doesn't appear to require rocket surgery - it looks almost exactly like the boxes on the Kimmo Saunisto site.
..who do you think the IP behind Dutch & Dutch "is"?
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Old 14th January 2019, 01:13 AM   #19
hollowboy is offline hollowboy  Australia
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Originally Posted by mitchba View Post
I agree [...]

And, the genesis right here on diyAudio
Thanks for the review link. I like that "there is virtually no speaker boundary interference", and it works in real world positioning. I've got a similar space - hard surfaces, lots of glass - and a partner who is OK with big speakers, but wants them close to the walls, not out in the room.

...and thanks for the thread link. I'd seen parts of that thread before (that's where I saw the Dutch & Dutch patent), but I didn't join the dots / didn't pay enough attention.

While he guards the info about exactly how the 8c has better rear rejection than the early prototypes, the prototypes are pretty good. I'm grateful for the additional good tips for DIY people he's mentioned.

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..who do you think the IP behind Dutch & Dutch "is"?
Again, I hadn't joined the dots.

What is the link - is he an employee, is his stuff listed as "prior art", was it just a jumping off point..?
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Old 14th January 2019, 04:20 AM   #20
ScottG is offline ScottG  United States
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..who do you think the IP behind Dutch & Dutch "is"?
..correction, looks like it's Keyser. (..who's also done similar work.) Probably the "Dutch" should have been a give-away, as opposed to "Fin".

Note the sig. line:
2-way: Waveguide + Cardioid-like


Hmm, their website seems down right now..

Home - Dutch & Dutch
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