I tried it, for a no baffle sub stack, of five 15" woofers. I wound up with two 7.5" panels on either side of the woofers' fronts, with a 6" slot .
Didn't bother plugging the tiny gaps between the woofers, as the two by four framing blocks all but 3/4" or so on each side.
This slot sub sounds better than the normally mounted woofers on my old Van Halens panels.
Subs would be pushing it 
https://www.diyaudio.com/forums/mul...20-20k-dipole-loudspeaker-38.html#post5922910
https://www.diyaudio.com/forums/mul...20-20k-dipole-loudspeaker-38.html#post5922910
Subs would be pushing it
Yes. Mine's barely a subwoofer, with EQ it's only reaching 32 hertz solidly on test tones.
It is better in my room than my two sealed, or single ported subs.
"Gallery"
Walnut 1505B horns, Peerless compression driver, 12" paper full range, crossed active at 120 and 10,000 hertz.
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I see your sub stack lurking in the background. Any reason for offsetting the slot from center?
It's an illusion.
The slot is centred.
It is just an experiment; this weekend, I'll replace these with full height 1 by 10s.
Hi Pengesluk,
sorry, just noticed your post right now.
If you intend to use a Fertin38ex and a Raal, I can´t help but imaging that a Fertin or EMS fullrange for the mids would be a better match. Compared several 8 inch drivers on my journey and have finally chosen the Fertin 21M8EX as main driver.
A modular approach is a good idea to try several drivers, but of course each driver will need its own alignments.
All the best
Mattes
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Mini-K’s With Open Baffle Bass
Posting this here as well the Mini Karlsonator thread.
I built some open baffles to experiment with adding more low end to my system this weekend. They’re roughly based on John Busch’s Manzanitas in terms of the GRS15 woofers, baffle size and wings and the 20mH inductor on the XO. I have an 8 Ohm mills resistor in series with the 0.53x Mini-k with dual 3fe25’s. I like what I’m hearing so far. They blend pretty well and give the low end I was missing along with some good punch on percussion. I think the woofers still need some break-in time to loosen up the surrounds and things will get even better. Maybe some more XO experimentation later this week too.
Posting this here as well the Mini Karlsonator thread.
I built some open baffles to experiment with adding more low end to my system this weekend. They’re roughly based on John Busch’s Manzanitas in terms of the GRS15 woofers, baffle size and wings and the 20mH inductor on the XO. I have an 8 Ohm mills resistor in series with the 0.53x Mini-k with dual 3fe25’s. I like what I’m hearing so far. They blend pretty well and give the low end I was missing along with some good punch on percussion. I think the woofers still need some break-in time to loosen up the surrounds and things will get even better. Maybe some more XO experimentation later this week too.
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Faital Pro mid tweeters?
Those are good drivers.
I'm coming around again to paper drivers.
So I have tried thick (about 3/16”) felt on the baffles for my fullrange drivers...(eventually found good material at a crafts store) they definitely have improved detail, and most of even the higher volume harshness is gone. Quite a big improvement.
So thank you very muchly!
I am now figuring how to implement something similar to your magnet mount and decoupled baffle.
Searching for line array open baffle speakers, I found these.
PIEGA | Master Line Source
I do not dare searching for their price
PIEGA | Master Line Source
I do not dare searching for their price
Searching for line array open baffle speakers, I found these.
PIEGA | Master Line Source
I do not dare searching for their price
I use 5 fifteen Inch woofers for 30 to 130 hertz, open baffle. Posted a photo as a response to a query on a Facebook site.
Some trolls went nuts, saying the 90" tall stack isn't a line array, and that at the frequencies I use it at, it is in fact a point source, and does not launch a cylindrical wave, nor does it boost efficiency by having the drivers in such close proximity.
OTH, I've heard a stack of woofers, and it does play loud and clean, with minimal excursion, lol.
IMO, the concept will also work fine in a box.
1/4 wavelength at 130 hz is about 2 feet, so it should have a bit of line source behaviour at its upper range, but 100 hz or below it becomes closer to a “point” source that’s feet wide?
The guy was getting ridiculously abusive, so I blocked him. He made little sense to me.
I'd already stated this was made from spare parts at hand, from possible replacements for projects I'd sold years ago, in case a customer blew drivers, or if one happened to fail.
He was telling me I should have bought new drivers for this, with higher Qts than the 0.50 ones I already had.
I understand some people like the 1.0qts sound in free air, but I'd rather use a drier sounding woofer, and eq it a little.
Next he goes off, pretending my old plate amp is a class D amp. It's not.
Then he complains that a thousand watt amp into a 4 ohm load is too much power. It's 500 watts into this 8 ohm load, besides the fact that it too, is a spare from a previous sold project, again, in case the sold amp fails on the customer.
Then he attacks using 1*8"*90" timber at hand, to slot load the front output to a 6" *90" opening on the woofer stack, adding resistance and bass depth. I did it to avoid more hole cutting( it's messy) and to decouple the woofers from a frame, rather than using a resonance generating regular style baffle.
I looked over the troll's other postings, and decided not to engage with a know it all know nothing,and blocked him before he explained a 90 inch, 130 hertz point source.
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Yeah MIT, there are always detractors. If anything, no amount of thinking or knowledge I may have can compare to the folks who actually build something. Some people will criticize or complain without trying to be constructive. Those are the ones who end up with a head full of unfulfilled ideas and just rain their crap on everyone else.
I run a pair of 18s in Hframes on each side and if I had 4 more, they'd be stacked floor to ceiling.
As for the QTS of the woofer... I have toyed with the idea of trying a lower QTS bass driver, especially now that DSP is on hand, and feel like you're chasing something a little more worthwhile with a low QTS driver over say a 1.5 QTS driver. That said, the proof is in the pudding... I'd have to take a chance and try before I could criticize or pontificate... And me lecturing anyone is not likely LOL.
I love this thread. Always keeps giving great posts.
I run a pair of 18s in Hframes on each side and if I had 4 more, they'd be stacked floor to ceiling.
As for the QTS of the woofer... I have toyed with the idea of trying a lower QTS bass driver, especially now that DSP is on hand, and feel like you're chasing something a little more worthwhile with a low QTS driver over say a 1.5 QTS driver. That said, the proof is in the pudding... I'd have to take a chance and try before I could criticize or pontificate... And me lecturing anyone is not likely LOL.
I love this thread. Always keeps giving great posts.
Over the years I have used both high Qts and low Qts drivers on plain open baffle, u-frame, h-frame and w-frame
While I'm not very certain whether it all came down to the Q factor of the drivers but the lower Q drivers sounded better to my ears, with help from eq that is.
Just to name a few, I have tried the very well known Eminence Alpha 15 wich, in fact, was one of the worst 15" woofers I have ever had. It is mediocre build and sounds mediocre as well. It does not have much definition in the lower range and can't be used very high because it sounds pretty nasty from the lower midrange on up.
I also tried the Hawthorne Augie, which is also made by eminence. I did not like this one either. It sounds slow and sloppy, very low efficiency. It can't handle much power, it clips rather fast and it has a pretty noisy frame, spider and surrounds.
I also had a pair of high Qts goldwood drivers which gave somewhat the same results.
The lower Q drivers I have used where all of much better build quality, better spider, better surrounds, better frames, better behaved cones and they all sounded better accordingly. They do however require quite a lot of EQ but in the end they still sounded better. I have tried a few from Ciare, Faital Pro, JBL and Eminence.
To keep excursion within limits I stepped away from plain baffle and ended up with w-frames because they also cancel out any vibrations.
I ended up using w-frame dipoles with quite old JBL 2205 drivers with a Qts of 0.31. They have a Fs of 16Hz in the w-frame due to air coupling. This can play plenty loud and deep. In room power response goes down to 30Hz and they can be used up to 120-150Hz depending on crossover slope. It has more punch then with the high Q drivers on plain baffle.
I have not tried High Q drivers in a w-frame though, maybe it works just as good, or who knows, even better. I did not try it because other then bass extension I also prefered the sound of the lower Q drivers plain naked compared to the higher Q drivers. Again, it might just have to do with build quality. In general High Q PA drivers are the cheapest drivers out there and also cheaply build. Offcoarse there are better build high Q drivers out there but I didn't try them because I would have to buy them all.
So, yes, go ahead and try lower Q drivers. You might end up preferring them.
While I'm not very certain whether it all came down to the Q factor of the drivers but the lower Q drivers sounded better to my ears, with help from eq that is.
Just to name a few, I have tried the very well known Eminence Alpha 15 wich, in fact, was one of the worst 15" woofers I have ever had. It is mediocre build and sounds mediocre as well. It does not have much definition in the lower range and can't be used very high because it sounds pretty nasty from the lower midrange on up.
I also tried the Hawthorne Augie, which is also made by eminence. I did not like this one either. It sounds slow and sloppy, very low efficiency. It can't handle much power, it clips rather fast and it has a pretty noisy frame, spider and surrounds.
I also had a pair of high Qts goldwood drivers which gave somewhat the same results.
The lower Q drivers I have used where all of much better build quality, better spider, better surrounds, better frames, better behaved cones and they all sounded better accordingly. They do however require quite a lot of EQ but in the end they still sounded better. I have tried a few from Ciare, Faital Pro, JBL and Eminence.
To keep excursion within limits I stepped away from plain baffle and ended up with w-frames because they also cancel out any vibrations.
I ended up using w-frame dipoles with quite old JBL 2205 drivers with a Qts of 0.31. They have a Fs of 16Hz in the w-frame due to air coupling. This can play plenty loud and deep. In room power response goes down to 30Hz and they can be used up to 120-150Hz depending on crossover slope. It has more punch then with the high Q drivers on plain baffle.
I have not tried High Q drivers in a w-frame though, maybe it works just as good, or who knows, even better. I did not try it because other then bass extension I also prefered the sound of the lower Q drivers plain naked compared to the higher Q drivers. Again, it might just have to do with build quality. In general High Q PA drivers are the cheapest drivers out there and also cheaply build. Offcoarse there are better build high Q drivers out there but I didn't try them because I would have to buy them all.
So, yes, go ahead and try lower Q drivers. You might end up preferring them.