Disagree with that efficiency in terms of dB/watts doesn't change, can't cheat physics......however if you parallel the speakers, it will have a lower impedance though. So in terms of dB for 2.83Vrms input, it increases. I don't think its the reason why 6 speakers are used, just to get the surface area and because of the low x-max, more surface area is needed than usual....
Oon
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Oon
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I would explain what is happening in terms of the Coandă effect. We have entrainment and inducement. Coand? effect - Wikipedia, the free encyclopedia
Terry
Terry
I have some cheap 8",10" ideas for my own 'budget' SLOB attempt,
CHEAP SLOB as I like to call it!
What do you guys reckon to these drivers specs?
WS20E 4 Ohm order no. V-1057 EUR 25,15
21 cm bass driver with polyethylene cone.
power handling (continuous/programme) = 80/120 W
frequency range = -7000 Hz
resonance frequency fs = 47 Hz
impedance R = 4 Ohm
sound pressure level SPL = 91 dB (2,83V; 1m)
DC resistance Re = 3,3 Ohm
force factor BL = 4,5 N/A
voice coil inductance L = 0,7 mH
effective piston radiating area Sd = 240 cm2
effective mechanical mass incl. air load mms = 23 g
equivalent volume of compliance Vas = 39 l
total Q factor Qts = 1,14 (Qms=5,56, Qes=1,44)
voice coil diameter = 30 mm
mounting diameter d = 186 mm
overall diameter d = 236 mm
mounting depth (not countersunk) t = 85,9 mm
mass m = 1,3 kg
or in 8 ohm:
WS20E 8 Ohm order no. V-1056 EUR 25,15
21 cm bass driver with polypropylene cone.
power handling (continuous/programme) = 80/120 W
frequency range = -7000 Hz
resonance frequency fs = 47 Hz
impedance R = 8 Ohm
sound pressure level SPL = 88 dB (2,83V; 1m)
DC resistance Re = 6,8 Ohm
force factor BL = 5,5 N/A
voice coil inductance L = 1,0 mH
effective piston radiating area Sd = 240 cm2
effective mechanical mass incl. air load mms = 21 g
equivalent volume of compliance Vas = 44 l
total Q factor Qts = 1,23 (Qms=5,36, Qes=1,59)
voice coil diameter = 30 mm
mounting diameter d = 186 mm
overall diameter d = 236 mm
mounting depth (not countersunk) t = 85,9 mm
mass m = 1,3 kg
or a 10" rather than 8" driver:
open a bigger photo
WS25E order no. V-1061 EUR 35,20
26 cm bass driver with paper cone. The diaphragm is varnished with a hydrophabic coat.
power handling (continuous/programme) = 80/110 W
frequency range = -6000 Hz
resonance frequency fs = 34 Hz
impedance R = 8 Ohm
sound pressure level SPL = 88 dB (2,83V; 1m)
DC resistance Re = 5,9 Ohm
force factor BL = 3,8 N/A
voice coil inductance L = 0,8 mH
effective piston radiating area Sd = 346 cm2
effective mechanical mass incl. air load mms = 33 g
equivalent volume of compliance Vas = 113 l
total Q factor Qts = 1,43 (Qms=2,82, Qes=2,92)
voice coil diameter = 25 mm
mounting diameter d = 225 mm
overall diameter d = 283 mm
mounting depth (not countersunk) t = 107 mm
mass m = 1,25 kg
Only trouble with those is that no xmax is shown in spec.....
maybe just go crazy and slot load 12 of these:
W250 order no. V-9067 EUR 39,55
24 cm bass driver with high quality cone.
power handling (continuous/programme) = 90/130 W
frequency range = -6000 Hz
resonance frequency fs = 37 Hz
impedance R = 8 Ohm
sound pressure level SPL = 90 dB (2,83V; 1m)
DC resistance Re = 6,8 Ohm
force factor BL = 6,4 N/A
voice coil inductance L = 1,1 mH
effective piston radiating area Sd = 360 cm2
effective mechanical mass incl. air load mms = 27 g
equivalent volume of compliance Vas = 135 l
total Q factor Qts = 0,78 (Qms=3,57, Qes=1,0)
voice coil diameter = 35 mm
mounting diameter d = 236 mm
overall diameter d = 255 mm
mounting depth (not countersunk) t = 110 mm
mass m = 1,5 kg
Budget and QTS>0.7 as targets all these look prime game for an experiment!!!
CHEAP SLOB as I like to call it!
What do you guys reckon to these drivers specs?
WS20E 4 Ohm order no. V-1057 EUR 25,15
21 cm bass driver with polyethylene cone.
power handling (continuous/programme) = 80/120 W
frequency range = -7000 Hz
resonance frequency fs = 47 Hz
impedance R = 4 Ohm
sound pressure level SPL = 91 dB (2,83V; 1m)
DC resistance Re = 3,3 Ohm
force factor BL = 4,5 N/A
voice coil inductance L = 0,7 mH
effective piston radiating area Sd = 240 cm2
effective mechanical mass incl. air load mms = 23 g
equivalent volume of compliance Vas = 39 l
total Q factor Qts = 1,14 (Qms=5,56, Qes=1,44)
voice coil diameter = 30 mm
mounting diameter d = 186 mm
overall diameter d = 236 mm
mounting depth (not countersunk) t = 85,9 mm
mass m = 1,3 kg
or in 8 ohm:
WS20E 8 Ohm order no. V-1056 EUR 25,15
21 cm bass driver with polypropylene cone.
power handling (continuous/programme) = 80/120 W
frequency range = -7000 Hz
resonance frequency fs = 47 Hz
impedance R = 8 Ohm
sound pressure level SPL = 88 dB (2,83V; 1m)
DC resistance Re = 6,8 Ohm
force factor BL = 5,5 N/A
voice coil inductance L = 1,0 mH
effective piston radiating area Sd = 240 cm2
effective mechanical mass incl. air load mms = 21 g
equivalent volume of compliance Vas = 44 l
total Q factor Qts = 1,23 (Qms=5,36, Qes=1,59)
voice coil diameter = 30 mm
mounting diameter d = 186 mm
overall diameter d = 236 mm
mounting depth (not countersunk) t = 85,9 mm
mass m = 1,3 kg
or a 10" rather than 8" driver:
open a bigger photo
WS25E order no. V-1061 EUR 35,20
26 cm bass driver with paper cone. The diaphragm is varnished with a hydrophabic coat.
power handling (continuous/programme) = 80/110 W
frequency range = -6000 Hz
resonance frequency fs = 34 Hz
impedance R = 8 Ohm
sound pressure level SPL = 88 dB (2,83V; 1m)
DC resistance Re = 5,9 Ohm
force factor BL = 3,8 N/A
voice coil inductance L = 0,8 mH
effective piston radiating area Sd = 346 cm2
effective mechanical mass incl. air load mms = 33 g
equivalent volume of compliance Vas = 113 l
total Q factor Qts = 1,43 (Qms=2,82, Qes=2,92)
voice coil diameter = 25 mm
mounting diameter d = 225 mm
overall diameter d = 283 mm
mounting depth (not countersunk) t = 107 mm
mass m = 1,25 kg
Only trouble with those is that no xmax is shown in spec.....
maybe just go crazy and slot load 12 of these:
W250 order no. V-9067 EUR 39,55
24 cm bass driver with high quality cone.
power handling (continuous/programme) = 90/130 W
frequency range = -6000 Hz
resonance frequency fs = 37 Hz
impedance R = 8 Ohm
sound pressure level SPL = 90 dB (2,83V; 1m)
DC resistance Re = 6,8 Ohm
force factor BL = 6,4 N/A
voice coil inductance L = 1,1 mH
effective piston radiating area Sd = 360 cm2
effective mechanical mass incl. air load mms = 27 g
equivalent volume of compliance Vas = 135 l
total Q factor Qts = 0,78 (Qms=3,57, Qes=1,0)
voice coil diameter = 35 mm
mounting diameter d = 236 mm
overall diameter d = 255 mm
mounting depth (not countersunk) t = 110 mm
mass m = 1,5 kg
Budget and QTS>0.7 as targets all these look prime game for an experiment!!!
Visaton - Lautsprecher und Zubehör, Loudspeakers and Accessories
btw in normal OB 60x100cm qts 0,8 work well...
two x side with alpair FR can be nice and cheap speakers....
btw in normal OB 60x100cm qts 0,8 work well...
two x side with alpair FR can be nice and cheap speakers....
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Complete specs are at this obvious adress
Xlin = (Height of winding - Height of front pole-plate)/2
Xmax = Excursion limit
If you are into a really big bargain, look for this one.TSP are in the fact sheet.
Rudolf
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Thanks Rudolf! once again I was too lazy to add the Visaton link 
I think the last 2 of the Visaton drivers I mentioned are probbaly very good all round value.
However, the 12" driver Rudolf links is almost the same price and looks to be at the very least, better value per cm² of cone area. One thing I am sure of, and thats if I am making a Cheapo SLOB then I will use either of these Visaton 10" or the 12" Rudolf suggested. I wouldnt even bother with a singke pair of 8" unless you happen to find some with a high enough sensitivity. The way I see things, with a bigger woofer you dont need to load the driver as much (by reducing slot Sd). That is to say, the slot area can be bigger in proportion to the cone area, since you need to reduce Fs less. that should improve transient resp, and avoid 'heavy' sounding bass caused by reducing slot area too much. also you need less drivers. WIN WIN AFAIK. I will definately be considering that 12" driver in depth (thanks again Rudolf) for a 2x12" CHEAP SLOB sub, mated with a small fullranger, maybe the Alpair6's I have lying around.....
I think the last 2 of the Visaton drivers I mentioned are probbaly very good all round value.
However, the 12" driver Rudolf links is almost the same price and looks to be at the very least, better value per cm² of cone area. One thing I am sure of, and thats if I am making a Cheapo SLOB then I will use either of these Visaton 10" or the 12" Rudolf suggested. I wouldnt even bother with a singke pair of 8" unless you happen to find some with a high enough sensitivity. The way I see things, with a bigger woofer you dont need to load the driver as much (by reducing slot Sd). That is to say, the slot area can be bigger in proportion to the cone area, since you need to reduce Fs less. that should improve transient resp, and avoid 'heavy' sounding bass caused by reducing slot area too much. also you need less drivers. WIN WIN AFAIK. I will definately be considering that 12" driver in depth (thanks again Rudolf) for a 2x12" CHEAP SLOB sub, mated with a small fullranger, maybe the Alpair6's I have lying around.....
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In the spirit of using "a little imagination"...
What exactly is the resulting effect on performance of the slot loaded OB if maintaining the original projects baffle dimensions of 30 X 36...but modifying the baffle by creating wings within its total width to reduce the footprint of the baffle and increase WAF factor?
I had actually thought it might be elegant to create the baffle as a semi-circle interrupted by a central flat area big enough to allow the integration of the slots exit. I also thought of mimicking that semi-circular baffle profile on an upper panel that would integrate either a Fostex 107e or 206e for now. Both of which I have sitting on a shelf.
My ultimate interest here and in reading the entire thread was to try and determine if this design would be efficient and flexible enough to integrate into a system that I hope will eventually use a horn with one of these full range drivers.
I would like to be able to drive the entire system with a pair of 25 watt push/pull horn amplifiers I have horded as well...so it would be pretty important to have some specific guidelines as to a passive cross over design.
I do have a couple of multi-channel HT amps around but very little in the way of DSP abilities with my old Lexicon HT processor. The only other electronic crossover I have is an inexpensive 3-way automotive unit I never used with limited adjust-ability.
Any feedback would be appreciated.
Regards
Kevin
What exactly is the resulting effect on performance of the slot loaded OB if maintaining the original projects baffle dimensions of 30 X 36...but modifying the baffle by creating wings within its total width to reduce the footprint of the baffle and increase WAF factor?
I had actually thought it might be elegant to create the baffle as a semi-circle interrupted by a central flat area big enough to allow the integration of the slots exit. I also thought of mimicking that semi-circular baffle profile on an upper panel that would integrate either a Fostex 107e or 206e for now. Both of which I have sitting on a shelf.
My ultimate interest here and in reading the entire thread was to try and determine if this design would be efficient and flexible enough to integrate into a system that I hope will eventually use a horn with one of these full range drivers.
I would like to be able to drive the entire system with a pair of 25 watt push/pull horn amplifiers I have horded as well...so it would be pretty important to have some specific guidelines as to a passive cross over design.
I do have a couple of multi-channel HT amps around but very little in the way of DSP abilities with my old Lexicon HT processor. The only other electronic crossover I have is an inexpensive 3-way automotive unit I never used with limited adjust-ability.
Any feedback would be appreciated.
Regards
Kevin
Similar principal but both sides of the woofers are loaded which lower the resonance by increasing the load on the cones. I am now using six 10 inch low mass woofers per channel with a high Q. I have them made by Dc gold in California and am a distributor for them. Please contact me at hifiralph@yahoo.com if you have any more questions or want to purchase part to build my design. thanks Ralph
Dipole woofers need to have a total Q greater than .5 Eight inch drivers as not good in dipole because they do not move enough air. I have a unique design I will be showing at the Capital Audio Fest in DC that uses 6 ten inch drivers per channel. I have over 300 square inches of cone per channel I would highly recommend the Dc gold 10 inch drivers. I am a distributor for them and use them in my own design. I have looked high and wide for a good 10 inch dipole driver. Good luck on your project. Ralph
hifiralph, If you wish to post any commercially related posts (see post 372 and 374) Please open a thread in the vendors bazaar forum.
Doubt we will show that woofer at RMAF--or, if we did, there would not be room for anything in the room but the woofer! Maybe a line of piezo tweeters on top?
Definitely a "big room" design, although it will break down small enough to fit into my Volvo station wagon. Unloaded, it kinda looks like a piece of playground equipment!
We will get a chance to put this beast through its paces at the Munich show. It will be running @ ~80hz low pass.
On initial audition, it was very "potent" but it had an open and natural sound that mated quite well with the WE15A horns. A worthy technology, it seems...will have more to say after the show.
Madman jc morrison designed the woof. I think his idea of pairing the Altec 515B and EV 30W is supported by matched Xmax (and possibly Vas) between these two drivers but I wouldn't rule out sheer perversity as one of the design goals.
I'm sorry for my incorrect information. Apparently I misinterpreted a blog entry of yours at holgerbarske.com.
Rudolf
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