I'm starting to give electronic life to this new concept for the next revision of my speakers, which will include, ladies and gentlemen, an infrawoofer.
It will be in closed box, as I hate BR, and will cover the fist octave to give then the torch to dipole midbass.
After doing lots of simulations of drivers including Volt, Vifa, and many others, i narrowed my choice to two drivers from the excellent woofer Peerless line:
http://www.tymphany.com/categories/peerless/subwoofer
Upper Fs limit has been set at 25hz, lower the better, therefore discarding the models 830843, 830846. Low volume is also a plus in my book, as the infra(s) will be short, but they can be large taking floor space behind the rack.
Besides size, the the XXLS 10" units have the advantage of costing about HALF of the 12" XXLS. The amplifier that will power either one or
Of course, other inputs are welcome. The use will be for a very low frequency band (from 20 to 60hz), with low distortion. Therefore the driver will have low Fs, high Xmax and low Qt. The Qtc of the box (closed, if it wasn tclear) will also be rather low. Active equalization and bass boost will be used.
It will be in closed box, as I hate BR, and will cover the fist octave to give then the torch to dipole midbass.
After doing lots of simulations of drivers including Volt, Vifa, and many others, i narrowed my choice to two drivers from the excellent woofer Peerless line:
http://www.tymphany.com/categories/peerless/subwoofer
Upper Fs limit has been set at 25hz, lower the better, therefore discarding the models 830843, 830846. Low volume is also a plus in my book, as the infra(s) will be short, but they can be large taking floor space behind the rack.
Besides size, the the XXLS 10" units have the advantage of costing about HALF of the 12" XXLS. The amplifier that will power either one or
Of course, other inputs are welcome. The use will be for a very low frequency band (from 20 to 60hz), with low distortion. Therefore the driver will have low Fs, high Xmax and low Qt. The Qtc of the box (closed, if it wasn tclear) will also be rather low. Active equalization and bass boost will be used.
Good choice of drivers. Have you thought of drivers facing away from each other in a closed cabinet? The mounting cancels the reaction forces coming from the woofer cones, greatly decreasing both vibration within the cabinet and vibration transmitted to the floor. Could also suit your dipole midbass.
That's exactly what i thought, with the cabinet being a cylinder. 🙂
I'm not sure if i should connect the drivers as stereo or as mono in that case.
Simulations with winISD will follow.
Cylinder is a cool idea. Hope you can get the volume you need. I had a look at using a pair of SS 10" and needed ~110L. Given the low XO you might not need stereo but my preference would be stereo in with the option to sum to mono.
Those XXLS drivers are perfect for small closed boxes, but for low bandwith nothing beats a well designed 6th order vented> bang on for higher SPL and lower costs using cheaper 12" drivers. About the same size for a normal vented design with higher eff and more LF shaping options but without the need for all the extra electronic EQ boxes. But sealed is OK if low volume and low SPLs are good enough. see your chart of Xmax versus freq at 20-30 Hz, it is always tuff to do for any 10" I would not even attempt to venture there myself.
Single driver sub simulation in winISD.
the XXLS do NOT need big boxes. The Ideal size for my room is under 40lt for two boxes and about 70 for one big (tube).
It is quite obvious that the 830842 is good only for very small boxes, but it does not meet my SPL goals. The other two drivers performs very close in a 38lt box, with roughly equals a 30x30x60cm parallelepiped. I can probably go with either of them, but the silver one is a tiny better and cheaper.
Simulation two is with two drivers in 70lt box.
Also my preference is for stereo (also for equalization), I want to find out if i can do that putting both drivers in the same cylinder and wire them stereo.
It either works or is horrible 🙂
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I dont really have the space to use 12" drivers in the first instance.
Besides the 10" XXLS have very similar performance to the 12". I did comparing sims before.
The alternative i'm considering is a pair of tapped horns with 6-8" drivers. Problem is I dont have the space and some thin columns have to be designed. Like this one but in column:
http://www.volvotreter.de/th.htm
Exactly 😉 Volume seems reasonable and no apparent difference on the sims. And if it doesn't work you can always find a good home for these drivers in single sealed subs.
Hi,
IMO and IME: The submitted simulation of a T-TQWT will reach the infra octaves without any extra bass boost or needed Eq. or wasting excessive amp power and is more than 50 % efficient(>= 6 dB) at 20 Hz when compared to a closed variant.Further: The T-TQWT will be more 'silent' as the distortion generated above the pass band will be acoustically screened (low passed).
b
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Hi,
Further: The T-TQWT will be more 'silent' as the distortion generated above the pass band will be acoustically screened (low passed).
96lt... i wish i had that space, which would be the exact size? (i read only the height)
Well, if i persuade the WAF the tapped horn is definitely more efficient and clean than a closed box.
It's amazing how well this 10" peerless responds in such configuration, according to your simulation.
Hi Telstar,
You can build the T-TQWT occupying only about a square foot of floor space in a box with 135 cm( 53.15") internal height folded once. External dimensions about: H x W x D about 139 x 31.5x31.5 cm^3 or 54.7 x 12.3 x 12.3 cu inch.
b
Looks very good. Have to fight with WAF for that foot but I will 🙂
Do you think you could hemp me making the plans to send to the carpenter?
OK, i managed to make Hornresp work (still lots of the parameters I do not understand, but at least i could play with what determines lenght/size and response.
The shortest yet decent at low freqs would be 230cm and 81lt with L23=189 and L34=28
Folded once, the size should be acceptable. Not a big reduction, though.
Electrical Impedance, phase and group delay are worse at <40hz.
Not sure if the changes are worth... maybe the longer one folded 2 times...
The shortest yet decent at low freqs would be 230cm and 81lt with L23=189 and L34=28
Folded once, the size should be acceptable. Not a big reduction, though.
Electrical Impedance, phase and group delay are worse at <40hz.
Not sure if the changes are worth... maybe the longer one folded 2 times...
Hey there!
Im reviving this old thread because I didnt build the sub specced above. I have finally changed place and the new room allows for bigger enclosures*. Also the main speakers have changed and I need first octave coverage, about 15-45 hz from a PAIR of subs.
Drivers can be of bigger size, 15 or 18" as well. I will use the new hypex plate amp with dsp.
[* up to roughly 50x70x100 cm.]
Im reviving this old thread because I didnt build the sub specced above. I have finally changed place and the new room allows for bigger enclosures*. Also the main speakers have changed and I need first octave coverage, about 15-45 hz from a PAIR of subs.
Drivers can be of bigger size, 15 or 18" as well. I will use the new hypex plate amp with dsp.
[* up to roughly 50x70x100 cm.]
A fd of 19-20 hz should be optimal and there are woofers with fs close to that.
Maybe a tapered folded TL. I have to get back to sims. 🙂
Btw, if i use a dual bobbin woofer it would be powered by 700w each, which is the spec of the hypex 700 module (and im not sure on the 2 ohm support either), so I'm looking first at 4 ohm drivers.
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