Hi all,
I've read these forums tons over the years, finally courageous enough to post and ask for some guidance.
I'd like to use a pair of 10" drivers (per channel) to cover 30Hz - 300Hz, mating with a horn covering 300 & up.
The 10" drivers will be in slot-loaded open baffle configuration. I'm using class D amplification and DSP for eq.
Ideally I'd like this to be a two-way, so I'd wire both 10" drivers in parallel or series, instead of using one to cover let's say 30-125 and the other 125 - 300.
On the higher end I've looked at the Acoustic Elegance Dipole10's. I'm looking for some other choices, wonder what you all recommend.
All input is much appreciated!
I've read these forums tons over the years, finally courageous enough to post and ask for some guidance.
I'd like to use a pair of 10" drivers (per channel) to cover 30Hz - 300Hz, mating with a horn covering 300 & up.
The 10" drivers will be in slot-loaded open baffle configuration. I'm using class D amplification and DSP for eq.
Ideally I'd like this to be a two-way, so I'd wire both 10" drivers in parallel or series, instead of using one to cover let's say 30-125 and the other 125 - 300.
On the higher end I've looked at the Acoustic Elegance Dipole10's. I'm looking for some other choices, wonder what you all recommend.
All input is much appreciated!
Moved to multi-way since this isn't really a sub woofer, but part of a multi-way OB.30Hz in an OB requires a large baffle and a lot of displacement if any reasonable level of SPL is to be reached. The SLOB will not really change this, and will only add the slot's resonance.
If you did not need to reach 300Hz putting both drivers in a force cancelling configuration in an H- or U-frame would work. Unfortunately, these cannot be used up to 300Hz because they have a line resonance that produces a peak and then a dip, so you stay below that frequency. If your 10" drivers have rather large excursion capability, this will be helpful for getting to 30Hz. Linkwitz's LX521 uses two 10" Seas subs in a small M-frame (or whatever that is called) but even so he crosses over at 120Hz to his OB panel 8" driver.
You might re-consider the idea of using two different woofers each covering its own range. Use one in a 20" long U-frame to cover 30Hz to 120Hz. Use the other in an open baffle of modest size (e.g. 15"W or wider and at least as tall) , up to whatever frequency the driver can support. Both of these drivers will need a lot of excursion capability, and you will need to boost the power to the U-frame woofer. Even better would be to use a single larger driver (e.g. 15") in the U-frame and a 10 to cover 125Hz and up in an OB.
I have used a 12 in a 17x30" planar OB but only down to about 80Hz since this is where its excursion (9mm) can support the SPL level I am interested in reaching (100-105dB@1m). Don't forget that you have BOTH the driver's free-air Qts response PLUS the additional loss from the OB or H/U/or M-frame dragging down the SPL at the low end.
If you did not need to reach 300Hz putting both drivers in a force cancelling configuration in an H- or U-frame would work. Unfortunately, these cannot be used up to 300Hz because they have a line resonance that produces a peak and then a dip, so you stay below that frequency. If your 10" drivers have rather large excursion capability, this will be helpful for getting to 30Hz. Linkwitz's LX521 uses two 10" Seas subs in a small M-frame (or whatever that is called) but even so he crosses over at 120Hz to his OB panel 8" driver.
You might re-consider the idea of using two different woofers each covering its own range. Use one in a 20" long U-frame to cover 30Hz to 120Hz. Use the other in an open baffle of modest size (e.g. 15"W or wider and at least as tall) , up to whatever frequency the driver can support. Both of these drivers will need a lot of excursion capability, and you will need to boost the power to the U-frame woofer. Even better would be to use a single larger driver (e.g. 15") in the U-frame and a 10 to cover 125Hz and up in an OB.
I have used a 12 in a 17x30" planar OB but only down to about 80Hz since this is where its excursion (9mm) can support the SPL level I am interested in reaching (100-105dB@1m). Don't forget that you have BOTH the driver's free-air Qts response PLUS the additional loss from the OB or H/U/or M-frame dragging down the SPL at the low end.
Ah, nice to find someone else who likes to listen nice & loud. Thank you for your input!
On the low end, getting down to 30Hz will lean on DSP/EQ and room placement.
Your observation about the slot's resonance is spot-on. I'm trying to balance aesthetics / WAF and sonic integrity. This seems doable for 30 - 120, as you point out. It's the 120-300 that's tricky.
So one possible solution:
3-way, with a horn covering 300 & up, a SLOB subwoofer doing 30 - 120ish, and an OB (not slot-loaded) woofer covering 120 - 300.
What's the smallest driver I could get away with using for 120 - 300, if I'm using a pair of them per channel?
On the low end, getting down to 30Hz will lean on DSP/EQ and room placement.
Your observation about the slot's resonance is spot-on. I'm trying to balance aesthetics / WAF and sonic integrity. This seems doable for 30 - 120, as you point out. It's the 120-300 that's tricky.
So one possible solution:
3-way, with a horn covering 300 & up, a SLOB subwoofer doing 30 - 120ish, and an OB (not slot-loaded) woofer covering 120 - 300.
What's the smallest driver I could get away with using for 120 - 300, if I'm using a pair of them per channel?
For the OB operating from 120Hz and up you could use a single 10" with a good amount of Xmax. No need for a pair. A driver that would work well for this range is the Peerless SLS 830668.
I assume the 300Hz horn you will use is not small, maybe 20" wide or more and the OB will be that wide. I suggest placing the dual-10 SLOB at bottom (at the floor). Continue the baffle above for 12"-18" and mount the 10" SLS (non slot loaded) there. You could then place the horn on top of the baffle and it will be at about the right height. The SLS will benefit from the whole baffle including that part for the SLOB.
Keep in mind that the radiated acoustic power for the same on axis SPL will be different for the horn and the OB dipole and you may need to do some tweaking by ear of the response around 300Hz through the crossover region.
Thank you. I noticed on the Petit Orgue that the rear wave of the woofers fire into the same cavity as the front wave of the subwoofers. Two questions about this:
1. Is it important to have separate "boxes" for the rear waves of drivers handling different frequency ranges?
2. Would the subwoofers be wired reverse phase from the woofers in that Petit Orgue design? (just curious)
And...
3. Could I position the 10" woofer and the 10" subwoofer next to each other horizontally (instead of vertically)?. Separated by a couple inches of space. Like this:
[O|O]
And hopefully get away with only using one of each (instead of two subwoofers).
As always, super grateful for your guidance...
1. Is it important to have separate "boxes" for the rear waves of drivers handling different frequency ranges?
2. Would the subwoofers be wired reverse phase from the woofers in that Petit Orgue design? (just curious)
And...
3. Could I position the 10" woofer and the 10" subwoofer next to each other horizontally (instead of vertically)?. Separated by a couple inches of space. Like this:
[O|O]
And hopefully get away with only using one of each (instead of two subwoofers).
As always, super grateful for your guidance...
The Patent and construction is from Axel Ridthaler, a german engineer. Here is a link to his Withpaper: http://ridtahler.de/Resources/RiPol-Technik-Information.pdf
Normaly the two chassis fire in one front slot and separate back slots. Visaton has reversed it to get the full range between the bass-chassis. Important is the area of front and back openings....
Normaly the two chassis fire in one front slot and separate back slots. Visaton has reversed it to get the full range between the bass-chassis. Important is the area of front and back openings....
Getting down to 30Hz on an open baffle isn't easy.
To give you an idea, an experimental OB I did a little while ago used a Beyma 15P1200Nd a side, on a ~500mm width baffle. I needed around 27dB of boost at 25Hz to get the bass up. Decent SPLs could be had at 4m listening distance, but if any low stuff came along, cone excursion would easily get to 30mm p/p. I crossed to a 10" driver at 150Hz. I did try the 10" driver running down into the bass, but quickly found the limits. You could get away with aiming for 60Hz out of a 10" driver a side, but headroom was still limited (10" was a Faital Pro 10FH520).
If I was to build that OB again, I'd use a pair of 15"s a side for more headroom if I wanted to hit 25Hz.
30Hz is only a little easier. If you want it loud, I think 3x 12"s would be a minimum.
Chris
To give you an idea, an experimental OB I did a little while ago used a Beyma 15P1200Nd a side, on a ~500mm width baffle. I needed around 27dB of boost at 25Hz to get the bass up. Decent SPLs could be had at 4m listening distance, but if any low stuff came along, cone excursion would easily get to 30mm p/p. I crossed to a 10" driver at 150Hz. I did try the 10" driver running down into the bass, but quickly found the limits. You could get away with aiming for 60Hz out of a 10" driver a side, but headroom was still limited (10" was a Faital Pro 10FH520).
If I was to build that OB again, I'd use a pair of 15"s a side for more headroom if I wanted to hit 25Hz.
30Hz is only a little easier. If you want it loud, I think 3x 12"s would be a minimum.
Chris
Here is my approach. From my research and experience (been playing with OBs for like 6 years now), there is no reason not to use a subwoofer (or two) to 80hz or so. There are many good ones that are easy to acquire or build. Then use large pro woofers for the low end of 80-250; use a good mid-range from 250-2500; open back AMT tweeter from 2500 on up. As far as I am concerned the mid-range is where it is at (covering the vocal range, etc).
Attaching my latest iteration which has changed often in my quest.
Attaching my latest iteration which has changed often in my quest.
Attachments
The kind of system pictured above gives you pretty much all that you could want from an OB/dipole. For the most part the baffle size used for each driver is small. This results in very good, even off-axis response. It's difficult to find a dipole driver for the tweeter. The AMT is too large but does fit the general requirement. Others have used a B&G Neo3PDR without the back cup, and that is pretty good except for one area around 7kHz (IIRC). Once you get to pretty low frequencies you can go to a sealed sub but you will no longer have dipole radiation. If the integration is done correctly that is not a big problem, and dipole bass below 80-100Hz starts to become very large if any real SPL is to be had. The only solution is to fold the baffle into a U-frame or similar short transmission line, but this causes resonances to develop between 100-300Hz that limit the upper frequency to which it can be used. I am currently working on a partially folded H-frame system that may avoid the worst of these problems while still providing a reasonably long front-to-back pathlength.
After some contemplation, here's where I'm at. Feedback welcome.
The main issue here is how to cover 30 - 300 Hz in a not-big (but not small) cabinet, mated with a proper horn covering 300 Hz and up (Le'c flare, 30" diameter).
Is a two-way possible? Seems unlikely. So, a three-way.
20 - 80 Hz
2x 12" or 15" drivers... how about using an aperiodic vent? Can I slot-load the front wave?
80 - 300 Hz
1x dipole woofer, a 10" or 12"
Does 80 seem like the right xover point? Or should I bump it to, say, 125? I'm using digital amps & DSP so adjusting xovers is easy enough.
The main issue here is how to cover 30 - 300 Hz in a not-big (but not small) cabinet, mated with a proper horn covering 300 Hz and up (Le'c flare, 30" diameter).
Is a two-way possible? Seems unlikely. So, a three-way.
20 - 80 Hz
2x 12" or 15" drivers... how about using an aperiodic vent? Can I slot-load the front wave?
80 - 300 Hz
1x dipole woofer, a 10" or 12"
Does 80 seem like the right xover point? Or should I bump it to, say, 125? I'm using digital amps & DSP so adjusting xovers is easy enough.
FWIW, I find OB bass to be some of the best I've heard. The reason being that they don't excite rooms in the same way as monopoles.
I had a setup in one room for a while that put a 10dB spike in at 40Hz, and around 15dB at 12Hz. Took some hefty EQing to get those sorted (not impossible, though). The OB speaker, once the bass rolloff was accounted for, produced deep bass free from those room artifacts.
A 2-way speaker covering 20Hz-20kHz is just about possible. I did it with a good 15" driver and a good compression driver. 15" in a sealed box with EQ at the bottom end (you could go for a 20Hz-tuned ported box and EQ that) will get the bass, and then cross over in the 500Hz-1kHz range (depending on desired dispersion) to a compression driver with a 2.5-3" diaphragm. Add a supertweeter if you want, but a touch of boost past 10kHz on the compression driver will suffice for most people.
Chris
I had a setup in one room for a while that put a 10dB spike in at 40Hz, and around 15dB at 12Hz. Took some hefty EQing to get those sorted (not impossible, though). The OB speaker, once the bass rolloff was accounted for, produced deep bass free from those room artifacts.
A 2-way speaker covering 20Hz-20kHz is just about possible. I did it with a good 15" driver and a good compression driver. 15" in a sealed box with EQ at the bottom end (you could go for a 20Hz-tuned ported box and EQ that) will get the bass, and then cross over in the 500Hz-1kHz range (depending on desired dispersion) to a compression driver with a 2.5-3" diaphragm. Add a supertweeter if you want, but a touch of boost past 10kHz on the compression driver will suffice for most people.
Chris
It is not a Problem to go from 30Hz to 300Hz in an open baffle. As example the WS25E driver from Visaton. Take it on a 40cm/15,7 inch wide baffle (baffle Step around 300Hz) an place a 30Hz first order lowpass between amplifier an Chassis. It will run flat from 30Hz to 300Hz. But you will need multiple systems. The WS25e, with Vd=345qcm and 12mm Xmax, will produce a max Spl, at 30Hz, of 74dB on this baffle.
Why use Pro Woofers?
Hi
Why use pro woofers? They are made to handle high power not high excursion wich is what is needed in OB.
Scan Speak, Wavecor and AE have som very high excursion 12" woofers. Not cheap though.
Put 2 of them in a W-frame and you can play quite loud with a stereo pair. Double that to two W-frames a side that should do it.
Best regards
Uwe
PS a pair of Dayton Ultimax subwoofers would be ok too.
PPS W-frame is only good up to 150 Hz.
Hi
Why use pro woofers? They are made to handle high power not high excursion wich is what is needed in OB.
Scan Speak, Wavecor and AE have som very high excursion 12" woofers. Not cheap though.
Put 2 of them in a W-frame and you can play quite loud with a stereo pair. Double that to two W-frames a side that should do it.
Best regards
Uwe
PS a pair of Dayton Ultimax subwoofers would be ok too.
PPS W-frame is only good up to 150 Hz.
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