Hi Guys,
I have a couple of different projects, one of them being an open baffle speaker using the Bianco 18SW450 with Hypex FA123. I'm having second thoughts on that project and would like to ask what I might otherwise do with those two 18" drivers?
What sort of cabinet would they require to work as either two subs or even one push-push?
It just so happens that I'm also fooling around with some fullrange drivers, the SEAS FA22, and maybe the 18SW450 could even work as woofer in a WAW with the FA22?
Thank you
I have a couple of different projects, one of them being an open baffle speaker using the Bianco 18SW450 with Hypex FA123. I'm having second thoughts on that project and would like to ask what I might otherwise do with those two 18" drivers?
What sort of cabinet would they require to work as either two subs or even one push-push?
It just so happens that I'm also fooling around with some fullrange drivers, the SEAS FA22, and maybe the 18SW450 could even work as woofer in a WAW with the FA22?
Thank you
Greets!
With no 'bump', this 'fell through the cracks', so to speak.
Regardless, its specs works for many alignment types, just all are big, though prefer Onken alignment = 553.3 L/22.4 Hz Fb for vintage (HE) spec drivers, otherwise..........
Pioneer's Vas/1.44 = 257.2 L, Fb = Fs measured
T/S max flat alignment:
Vented net volume (Vb) (L) = 20*370.4*0.47^3.3 = 613.23 L
(ft^3 = (613.23)/~28.31685) = 21.66
Vented box tuning (Fb) (Hz) = 0.42*28*0.47^-0.96 = 24.8 Hz
F3 (Hz) = 28*0.28*0.47^-1.4 = 22.6 Hz
Sealed Calculator = 304 L max flat 0.7 Qtc
With no 'bump', this 'fell through the cracks', so to speak.
Regardless, its specs works for many alignment types, just all are big, though prefer Onken alignment = 553.3 L/22.4 Hz Fb for vintage (HE) spec drivers, otherwise..........
Pioneer's Vas/1.44 = 257.2 L, Fb = Fs measured
T/S max flat alignment:
Vented net volume (Vb) (L) = 20*370.4*0.47^3.3 = 613.23 L
(ft^3 = (613.23)/~28.31685) = 21.66
Vented box tuning (Fb) (Hz) = 0.42*28*0.47^-0.96 = 24.8 Hz
F3 (Hz) = 28*0.28*0.47^-1.4 = 22.6 Hz
Sealed Calculator = 304 L max flat 0.7 Qtc
I use a Bianco 18SW450 in an H-frame with a Hypex 251.
From 30-55Hz
The rest is covered by Sonido SWR 200 in tqwt.
It works pretty well for me.
I also have a 100l CB for the 18SW450.
EQ is not much different from the h-frame setting. Easily handled by the Hypex 251.
The CB offers more physical impact.
I use the CB in a very big room (8*10m with a 3.5m ceiling).
In my smaller room setup I use the h-frame.
I prefer the dipole characteristics of the h-frame. Less room modes and more musical details. It's a better match for the 8" fullrange speakers in my opinion.
From 30-55Hz
The rest is covered by Sonido SWR 200 in tqwt.
It works pretty well for me.
I also have a 100l CB for the 18SW450.
EQ is not much different from the h-frame setting. Easily handled by the Hypex 251.
The CB offers more physical impact.
I use the CB in a very big room (8*10m with a 3.5m ceiling).
In my smaller room setup I use the h-frame.
I prefer the dipole characteristics of the h-frame. Less room modes and more musical details. It's a better match for the 8" fullrange speakers in my opinion.
If you have two 18SW450:
I tried a w-frame sub with two 18SW450.
Fs was lower compared to the h-frame, force cancellation calmed down the enclosure vibrations und output was more than enough even for the big room.
It was just to heavy and big for me, that's why I built a compact h-frame with a single 18SW450 after the w-frame.
I tried a w-frame sub with two 18SW450.
Fs was lower compared to the h-frame, force cancellation calmed down the enclosure vibrations und output was more than enough even for the big room.
It was just to heavy and big for me, that's why I built a compact h-frame with a single 18SW450 after the w-frame.
Hello MiWi,
Could you share more details about both boxes?
I have 4x18sw450 from previous project and am thinking about reusing them in a different setup.
Was thinking about 60x60x60cm H-frames but could try W-frame too.
I only tried H-frames with 12'', long tunnel in comparison (70x35x35cm) and didn't have issue with resonance, nor vibrations (they played only 1,5 octave in nearfield though).
Could you share more details about both boxes?
I have 4x18sw450 from previous project and am thinking about reusing them in a different setup.
Was thinking about 60x60x60cm H-frames but could try W-frame too.
I only tried H-frames with 12'', long tunnel in comparison (70x35x35cm) and didn't have issue with resonance, nor vibrations (they played only 1,5 octave in nearfield though).
After some time with the H-frame I´m now using a compact W-frame again.
Even thogh the H-frame was built heavy (30mm MDF + slate slab on top), with higher output levels I didn´t like the enclosure vibrations.
I made a very compact W-frame which I´m using now. Enclosure vibrations are so much less than with the H-frame. I like it better.
The compact 2x18SW450 W-frame is apr. 62cm x 50cm x 52cm (outer dimensions)
So almost as small as one of my single H-frame, which is aprx. 50x50x50cm
If you compare two of the H-frames (wired in parallel) to the W-frame, the two H-frames give you about 1-2db more efficiency around 30-40Hz. Which means you just need a few watts more. I dont bother, because I use either a Hypex FA501 or Icepower 700AS1 with the subs.
The 18SW450 reach max excursion long before the limit of the amps.
Max SPL is the same for a double H-frame or the W-frame.
11mm cone excursion makes for 105db at 30Hz and 113dB at 40hz.
If you want a sketch for the W-frame, just let me know.
Even thogh the H-frame was built heavy (30mm MDF + slate slab on top), with higher output levels I didn´t like the enclosure vibrations.
I made a very compact W-frame which I´m using now. Enclosure vibrations are so much less than with the H-frame. I like it better.
The compact 2x18SW450 W-frame is apr. 62cm x 50cm x 52cm (outer dimensions)
So almost as small as one of my single H-frame, which is aprx. 50x50x50cm
If you compare two of the H-frames (wired in parallel) to the W-frame, the two H-frames give you about 1-2db more efficiency around 30-40Hz. Which means you just need a few watts more. I dont bother, because I use either a Hypex FA501 or Icepower 700AS1 with the subs.
The 18SW450 reach max excursion long before the limit of the amps.
Max SPL is the same for a double H-frame or the W-frame.
11mm cone excursion makes for 105db at 30Hz and 113dB at 40hz.
If you want a sketch for the W-frame, just let me know.
Attachments
Great thank you, even more compact than I thought!
Good to learn about the vibrations I will then pay attention there.
Sketch not needed it was more for the global idea, did you pick the angle for the compactness?
Good to learn about the vibrations I will then pay attention there.
Sketch not needed it was more for the global idea, did you pick the angle for the compactness?
I started the horn response simulations with crossections of a ripol design.
The cross sections on driver axis are still that numbers.
Than I angled the baffles. For two reasons:
1: I can mount the drivers without the need to split the enclosure. And the magnets fit and have enough space at the magnet hole to breath. The edge of the magnet which ist closer to the back wall almost hits the back wall (1mm). Duevto the angle and the shape of the 18SW450 there is much more space behind the magnet hole.
2. The tapering smoothes the typical bumps and dips a bit.
It's not needed with a dsp and a steep lowpass at 40-45hz. But it's nice to have.
The cross sections on driver axis are still that numbers.
Than I angled the baffles. For two reasons:
1: I can mount the drivers without the need to split the enclosure. And the magnets fit and have enough space at the magnet hole to breath. The edge of the magnet which ist closer to the back wall almost hits the back wall (1mm). Duevto the angle and the shape of the 18SW450 there is much more space behind the magnet hole.
2. The tapering smoothes the typical bumps and dips a bit.
It's not needed with a dsp and a steep lowpass at 40-45hz. But it's nice to have.
This looks like a nice design! Just trying to learn here--I'm curious about the pros and cons of a very shallow-angled W-frame as you executed, and having the drivers directly face each other in a full ripole configuration?
The ripole should in theory have (slightly) fewer cabinet vibrations with the drivers directly opposed on axis, but I'm not clear about the impact on slot loading, max frequency you could play up to, or other considerations?
The hornresponse simulations between a ripole design and this design with slightly angled baffles we're only slightly different.
The angled version has a little less pronounced resonance peak. But not by much.
But the main advantage fore was that I didn't need to split the whole thing into 2 or 3 parts. Or cut out holes for the magnets. The overall width and the cross section in front and behind driver axis are the same.
The drivers can be mounted from the front, because of the wider entry. And the back chambers are just big enough for the magnets to fit (the edge of the magnet has a 1-2mm clearance, but due to the angle there's still plenty space for ventilation)
The angled version has a little less pronounced resonance peak. But not by much.
But the main advantage fore was that I didn't need to split the whole thing into 2 or 3 parts. Or cut out holes for the magnets. The overall width and the cross section in front and behind driver axis are the same.
The drivers can be mounted from the front, because of the wider entry. And the back chambers are just big enough for the magnets to fit (the edge of the magnet has a 1-2mm clearance, but due to the angle there's still plenty space for ventilation)
This are the hornresponse simulations of w-frame vs. ripol.
Both have 24cm path front / back
Both have 870cm² and 1480cm² cross-section in front / behind the driver axis.
The ripol lowers the resonance down to 18Hz.
The W-frames resonance is 20Hz
(SB18450 has fs = 28Hz)
The W-frame has 1-2dB more efficience from 30-100Hz.
The peak ist shiftet a bit higher / further out of the passband (200Hz ripol, 250-260Hz W-frame)
I use a DSP with 4th order LR lowpass at 50Hz and I eq the peak. So both responses would be fine for what I use the subwoofer for.
I don´t care about 18Hz or 20Hz resonance, I use a 25Hz highpass anyway.
The main advantage for me is the easy construction of the enclosure and the easy mounting of the drivers.
Both have 24cm path front / back
Both have 870cm² and 1480cm² cross-section in front / behind the driver axis.
The ripol lowers the resonance down to 18Hz.
The W-frames resonance is 20Hz
(SB18450 has fs = 28Hz)
The W-frame has 1-2dB more efficience from 30-100Hz.
The peak ist shiftet a bit higher / further out of the passband (200Hz ripol, 250-260Hz W-frame)
I use a DSP with 4th order LR lowpass at 50Hz and I eq the peak. So both responses would be fine for what I use the subwoofer for.
I don´t care about 18Hz or 20Hz resonance, I use a 25Hz highpass anyway.
The main advantage for me is the easy construction of the enclosure and the easy mounting of the drivers.
Thanks so much for the additional explanation and details! Very interesting to see. The shallow W really is quite compact for holding dual 18" drivers.
So the stronger slot loading of the ripole drops the Fs more, but at the "expense" (if a concern for your system) of cavity resonance peaking lower as well?
If too far off topic let me know, but as a thought experiment, would this be true as well with different geometry? The example that comes to mind would be taking an h-frame and putting wedges only on the front side to reduce the open area to 1/3 Sd. Or if the h-frame were based on a tube, putting a cone on the front side to achieve a similar loading.
So the stronger slot loading of the ripole drops the Fs more, but at the "expense" (if a concern for your system) of cavity resonance peaking lower as well?
If too far off topic let me know, but as a thought experiment, would this be true as well with different geometry? The example that comes to mind would be taking an h-frame and putting wedges only on the front side to reduce the open area to 1/3 Sd. Or if the h-frame were based on a tube, putting a cone on the front side to achieve a similar loading.
Yes.
Those experiments you mention: I usually use hornresponse to see what it does.
But with the subs it´s quite simple as far as I understand. Put some air mass on any side of the driver and you lower fs of the system and you get some kind of cavity resonance on the other hand and some kind of upper mass rolloff. Both shift up and down depending on the depth and volume of the cavity.
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Right, added mass = higher Qes', Qts' = lower Fs, Fhm*
Qes'= Qts'*Qms/(Qms-Qts')
(Qts'): (Qts) + any added series resistance (Rs):
https://web.archive.org/web/20220707003028/http://www.mh-audio.nl/Calculators/newqts.html
*upper mass corner = 2*Fs/Qts'
Qes'= Qts'*Qms/(Qms-Qts')
(Qts'): (Qts) + any added series resistance (Rs):
https://web.archive.org/web/20220707003028/http://www.mh-audio.nl/Calculators/newqts.html
*upper mass corner = 2*Fs/Qts'