Bookshelf 3 way Dayton Signature build (Cardoid?)

[Ktacos]

Trying my hand at a kii seven like speaker. I wanted to try and play with active cardoid pattern control with drivers I already had. Tweeter is ND25fw and woofers are the 5 1/4" and 7" signature woofers. I figured even if the cardoid stuff doesn't work out it will make a nice compact 3 way speakers. Cabinet volumes for mid and woofer are unknown to me at the time but they are small for both, I figured the mid range would be fine with it's volume and it is, and the sig180 is putting out a lot of low end for having such a small volume to work with and being sealed. I'm satisfied with one woofer and will pursue adding a second. I currently only have a single sig180 installed per cabinet as I had the drivers already and wanted to see if a single could even deliver adequate low end in the small volume, so far it seems but should benefit from adding a second.

As far as cardoid goes, I understand it would be applying a delay and phase shift to acheive some cancellation. I currently use EQ APO for my filtering and I'm unsure how to manipulate phase with it, or if it can at all. I assume rephase would be capable of exporting the appropriate filters. Any advice on this aspect of the speaker is welcome.

Nothing super amazing data wise yet, taken at LP maybe 7ft away or so, loud enough for me.

Distortion not SPL calibrated, feels like 75-80 which is about the max I listen at.

Currently the speakers have a 3/4" round over but I plan on increasing that to 1" once the bit arrives.

 

[Ktacos]

Alrighty, not sure if I'll finish this one out. I mounted two woofers in the back in push push configuration. While there was plenty of bass, it sounded quite strange. Basically all I could get bass wise was the kick, and tonal aspects to the low end like a bass guitar/synth seemed to just kinda almost null themselves. Despite measuring polarity and making sure everything was in check, my brains "phase ain't right" alarm kept going off.

 

[Gabbocasa]

Alrighty, not sure if I'll finish this one out. I mounted two woofers in the back in push push configuration. While there was plenty of bass, it sounded quite strange. Basically all I could get bass wise was the kick, and tonal aspects to the low end like a bass guitar/synth seemed to just kinda almost null themselves. Despite measuring polarity and making sure everything was in check, my brains "phase ain't right" alarm kept going off.

That's strange, sub should be in phase, aside from that I think the subwoofer part should be as far forward as possible, or this is what I deduce from seeing the photos of the originals that have some slots for the midwoofer motor to keep the volume separation further forward. In the future I will also try to redo these kii with two 2-channel hypex plates (one channel for the part with the mid and tweeter divided by a passive crossover and the second channel for the subs). The subs will probably have a crossover around 400/500hz above these frequencies the cardioid should no longer be needed, but it is a supposition, very few information has been given for these speakers

 

[Ktacos]

That's strange, sub should be in phase, aside from that I think the subwoofer part should be as far forward as possible, or this is what I deduce from seeing the photos of the originals that have some slots for the midwoofer motor to keep the volume separation further forward. In the future I will also try to redo these kii with two 2-channel hypex plates (one channel for the part with the mid and tweeter divided by a passive crossover and the second channel for the subs). The subs will probably have a crossover around 400/500hz above these frequencies the cardioid should no longer be needed, but it is a supposition, very few information has been given for these speakers

I haven't gotten around to trying any cardoid stuff, no point if the low end doesn't even sound right when using them as a regular ole 3 way speaker.

 

[Wolf]

What slopes are you using mid to woofer? Sometimes this involves flipping the mid polarity so they don't null in the xover range.

 

[Halbknapp]

I could advise on how to do the cardioid. You need to have a 90 deg. Phase difference and preferably a falling frequency response from the side woofers. You may in the Bass opt for no phase difference so the volume adds up. Note that enclosure tuning and all frequency response shaping will change phase. So the only active way to get this right is to measure, simulate and use FIR filters to change volume and phase of the side woofers separate so that it adds or cancles correctly.

There is a way to do this passive which I implemented - in this case a few prerequisites have to be met (woofers have to have sqrt(2) lower resonance in the enclosure and be 6db less loud (can be achieved if same woofer and enclosure is used by doubling moving mass mms). Then add a coil and resistor in series to the rear woofer (ballpark of 6,8mh and 8,2Ohm - tweak in simulation) - this will change the phase of the rear woofer to suite the cancellation. Reverse woofer is connected inverse.

Sorry that there is no super easy way to do this.

Regards, Ralf

 

[Halbknapp]

That's strange, sub should be in phase, aside from that I think the subwoofer part should be as far forward as possible, or this is what I deduce from seeing the photos of the originals that have some slots for the midwoofer motor to keep the volume separation further forward. In the future I will also try to redo these kii with two 2-channel hypex plates (one channel for the part with the mid and tweeter divided by a passive crossover and the second channel for the subs). The subs will probably have a crossover around 400/500hz above these frequencies the cardioid should no longer be needed, but it is a supposition, very few information has been given for these speakers

From my experience it gets extremely hard to cancel mid frequencies with side woofers above a few 100hz. It's better if the side woofers or are in close proximity to the front but that is again easier to achieve with slotted side it seems.

 

[Gabbocasa]

From my experience it gets extremely hard to cancel mid frequencies with side woofers above a few 100hz. It's better if the side woofers or are in close proximity to the front but that is again easier to achieve with slotted side it seems.

yes I can imagine the difficulty in doing it with active woofers instead of side slots. Looking at some pictures of the kii three on the inside you can see the molds with shapes to keep the mid and lateral woofers as close as possible, I have already built the Dutch & Dutch in DIY version and as a next project I would like to redo the kii seven, but active with 2 channels for speaker (one channel for mid and tweeter crossed in passive, and the other channel for an active crossover between mid and sub) which is what I also did for the Dutch&Dutch DIY. The problem is that I have little knowledge of FIR filters, I will have to study them. I think the Kartesian wom180, sb17nbac35 and sb26stwgc subs could be suitable components, maybe in the future I'll try.

 

[Ktacos]

What slopes are you using mid to woofer? Sometimes this involves flipping the mid polarity so they don't null in the xover range.

4th order active. I don't flip polarity on really any driver, never sounds right to me.

Just gonna shelf this one, have seen a few others with similar layouts achieving mediocre to poor results.