Full Range + Bass Driver Hybrid Open Baffle, Passive Xover or Active DSP

Hi all,

I'm toying with some plans to make a pair of hybrid open baffle speakers, the full range on the open baffle and a bass reflex cabinet enclosure at its base with a bass driver and tune it somewhere around 30~35hz. This is pretty much for music listening only, and for fun, doesn't need to get much lower than 30hz really for what I listen to. After tinkering with some drivers in XSim and building some passive crossovers, I'm finding I'm at around $95 in crossover parts pretty often. This has me thinking I could just spend a tiny bit more on a multi-channel DSP and do it that way instead, with a lot more latitude to play and change things or re-use it with other drivers at any time without having to break wire, solder, etc.

I was wondering if the Dayton DSP-408 (8 channel) at $165 could be topped for value? From what I'm reading I cannot use REW EQ files and just import unlike my miniDSP HD, which is a bummer, but I can't seem to find anything even remotely inexpensive for a basic DSP with several channels. I like the miniDSP HD, but it costs quite a bit to have as a dedicated active crossover DSP and EQ for some non-high-end speakers like this. While the DSP-408 isn't much cheaper, it's still only a bit more than physical passive crossover parts would be, so it just seemed like an option.

I can't seem to find a basic 4 channel DSP that takes REW filter output? The non-HD MiniDSP seems discontinued?

Thinking about trying some of Dayton's Reference 3" or 4" full-range drivers. I have some Visaton BG20's that I want to tinker with too. Was thinking of GRS 12" HE series drivers for the bass drivers as they're pretty good value for cost and I've used them before.

Very best,
 
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Hrm,

Anyone used the Thomann t.racks dSP 4x4 Mini?

https://www.audiosciencereview.com/...ds/thomann-t-racks-dsp-4x4-mini-review.33306/

Seems to not be totally garbage and is about $100. That's about what cross over components would cost. It's 4 channels. Might do the job? Edit: Rats, its $30+ in shipping, so its almost $140 to my door. A DSP-408 is $165 and has double the channels. No brainer there.

Very best,
 
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Toying with a crossover in XSim. This is my weakest point honestly. This may be a bad match of drivers, but I'm trying to smooth this out a little assuming a passive crossover approach. Was thinking of crossing closer between 120~250hz between the 4" full range driver and the 12" bass driver. But wasn't able to get a graph I liked so far.

I know I'm not modeling an Open Baffle in this, I was just toying with these two drivers in XSim mostly to remind myself what things even are in the crossover network again. I need to learn to use BASTA for the Open Baffle modeling, but there's even less tutorials out there for that, so its slow going with trial and error. That said, back up plan is to just mount the drivers and use UMIK1 and REW to build measurements to model from and use active DSP/EQ to handle the response of the drivers and baffle.

https://www.parts-express.com/Dayto...ce-Full-Range-Driver-4-Ohm-295-378?quantity=1
https://www.parts-express.com/GRS-1...r-Surround-Subwoofer-4-Ohm-292-820?quantity=1

This crossover and impedance looks absolutely awful lol. Sigh.

Very best,

1693777933299.png
 
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Playing around in Basta with the Visaton BG20 to get an idea of baffle width and effect.

Treble falls off rapidly. Any tips with the baffle shape or width to bring it back up at all?

If I could get that response to 100hz or so, I'd be happy with that for an open baffle stereo and would plan on bass reflex 12" subs integrated in the bass. Or possibly explore slot loaded bass drivers.

Very best,

1693780681969.png
 
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I take it you're putting the driver up in the corner while looking for smoothness on one axis? It can be difficult to see a way out when looking at things from this perspective. It means that most of the baffle is only there for minor support of one axis but is doing little to baffle the front to back path which may be dominated by the corner. Are you clear on the purpose of open baffle in your case or just trying it out?

I wonder if this is one of those cases where too much information can be unhelpful since there is usually no clear answer to many open baffle questions. Have you seen Pano's recent journey setting up an open baffle? - https://www.diyaudio.com/community/threads/18-coax-on-open-baffle-bm18cx-38.402195/
 
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Thanks; was just looking at the different response and yes just trying things to see how the model changes. I'm very new to Basta so trying to get a quick dirty feel for what does what.

Thanks for the thread link; interesting stuff!

Yes, too much info can easily be over the top. Unlike traditional speaker design or even just basic sub design, open baffle stuff and hybrids of open baffle and integrated subs are like trying to find ultra niche stuff that normally you'd find tons of in niche communities like this and reddit, but alas, none of that seems to be the case.

Very best,
 
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That's true, but not what I'm talking about. If I asked someone to define the aims of a monopole (regular box) design, they may.. but what are the aims of an open baffle? Is there a definition of perfection that you can design toward, or is it a matter of finding out what is audible and what isn't?
 
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Hrm, mostly I just like the idea of less boundary interaction, off axis SPL dropping a lot and the overall airy sound of the mids. I am one of the first to admit that I'm rarely after perfection, nor the idea of flatness, I know I like a little more sub-bass than is true to the recording and I actually dislike humped up mid-bass. I've listened to some open baffle but haven't made some and I fancy the idea of trying it and tweaking and all. If I can make something decent I'd love to make some out of some attractive wood slabs. I love how those look. I have the BG20's just sitting here so figured I'd try them. But also want to try some of the inexpensive Dayton Reference ones that are smaller. Otherwise, I really like the value in the Lii Fast 8's for cost. I may get those next.

Another part of me wants to work with full range drivers more and use the cabinet design to manage the low end response and make single driver enclosures with no crossovers. Kind of like the transmission line designs with full range drivers I've looked at that commonly are included with drivers like the Lii Fast 8's. Not because they're better, I realize they're not, mostly just out of interest and intrigue to make something with less.

Very best,
 
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I didn't mean perfection of course, I meant is there a defined purpose where you can say it is achieved...

OK, you mentioned less boundary interaction so that means you want the nulls to the sides. This means you don't want an open baffle per se, you want a dipole. A dipole is a special case of open baffle where the directivity is the goal. It is possible to aim toward this specifically so analysis like you were doing above can take on purpose. Of course, you won't be looking so hard at the on-axis performance and more on the quality of nulls.

A dipole is a funny thing as a speaker. It has nulls to the sides, but extra sound to the rear. Is this a conflict of purpose? I'd look at what the dipole builders have to say about placement within a room, to learn the way to benefit from this speaker type.
 
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Thanks, that makes sense, and that is more what I'm interested in, an open baffle dipole. It's specifically for music listening, nothing crazy bassy, classic rock, some jazz, some alternative, some piano. The rear SPL from the dipole is ok, I think there are clever ways to make use of it depending on the boundaries and distances in the room.

That said, I would love to have a better understanding of how to even begin to model these things. A video would be so lovely but I've yet to find one that even remotely covers this in the common software and isn't just a sales pitch from some salesman.

Very best,
 
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John Kreskovsky is considered an authority on the subject - http://musicanddesign.speakerdesign.net/ (archive site). John has a lot of grounding work on his site for educational purposes. Some of it is a little technical but it is offered with examples.

Seigfried Linkwitz is also an authority with a very helpful set of information - https://linkwitzlab.com/

There are others on this site such as CharlieLaub that are continuing work on moving toward smaller baffles to improve some of the properties of the speaker.
 
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