Hi Stewin,
Well, I feel a kind of consensus arising. 18"
Maybe, the SS15, as being a 40Hz-ish device, is NOT the best candidate for Club / DJ. I have a weak spot (ahum
) for smaller drivers, since they mostly don't break-up that easy (provided you don't buy the cheap ones). Also, since the SS15 is not that wide, I could stuff 4 of them (2 pairs mouth to mouth, on their side) under the stage to create a big consistent wave front. I like / favor central subs over subs om both sides, you want get the cancellation in the center. Usually, under a stage their is not much going on, except for loads of free space. AND 4 x 15" = 2 x 18" (roughly), so I have 2x 18". BUT the SS15 lack long enough path length. THAT could be the deciding factor here.
MAYBE a bigger SS15 (longer path), the SS15-ex(tended)?
Thank for your vote;
4 votes on 18"
0 votes on 15"
KEEP coming please
Kind regards,
Frans
Well, I feel a kind of consensus arising. 18"
Maybe, the SS15, as being a 40Hz-ish device, is NOT the best candidate for Club / DJ. I have a weak spot (ahum
) for smaller drivers, since they mostly don't break-up that easy (provided you don't buy the cheap ones). Also, since the SS15 is not that wide, I could stuff 4 of them (2 pairs mouth to mouth, on their side) under the stage to create a big consistent wave front. I like / favor central subs over subs om both sides, you want get the cancellation in the center. Usually, under a stage their is not much going on, except for loads of free space. AND 4 x 15" = 2 x 18" (roughly), so I have 2x 18". BUT the SS15 lack long enough path length. THAT could be the deciding factor here.MAYBE a bigger SS15 (longer path), the SS15-ex(tended)?
Thank for your vote;
4 votes on 18"
0 votes on 15"
KEEP coming please
Kind regards,
Frans
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Hi Stewin,
Maybe, the SS15, as being a 40Hz-ish device, is NOT the best candidate for Club / DJ. I have a weak spot (ahum
The problem is the SS15 is not a 40hz subwoofer. It starts rolling off pretty steeply between 50-55hz. By 40hz you're 8-10db down.
I can assure you cone break up is not a problem with the B&C 18" drivers. The frequencies are well within piston range, and the cones are very sturdy. The recommended driver for the SS15 (3015lf) on the other hand is very weak and will distort heavily when driven hard.
If the size of the SS15 appeals to you, there are other designs that have the low frequency extension of the Keystone and TH18, but they will sacrifice sensitivity.
Indoors I wouldn't spend too much time worrying about sub cancellation and wavefronts and such. Unless the room is extremely well treated, room modes are going to wreak havoc with whatever pattern you're trying to aim for. The only effective solution I'm aware of is scattering more subs across the room. The different overlapping modes tend towards evening out the response.
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And sensitivity is what we CANNOT lack here. I was looking for the B&C because of the robust construction.
Do you have a 15" alternative on DiyAudio at hand?
Kind regards,
Frans
http://www.diyaudio.com/forums/subwoofers/254752-oth40c-15-loaded-compact-th-flat-40hz.html
Here's one that I know of.
Here's one that I know of.
"Under driven" ?????
Can a tapped horn be "under driven". With that, I mean as an example, if I would choose to put say 4 keystones or SS15 with a capacity of say 4x 8 ohm / 3200 watt B&C speakers (parallel 2 pairs of 2 horn's) on a Crown amp with 2x 1200 watts on 4 ohms, each tapped horn would be loaded with max. 600 watt's (20 % of its driver capacity).
Looking in HR, the driver would have an xmax for that 600 watt load of no more than 6 - 8 mm of excursion. Even a HP filter would not be required. That would be a walk in the park, but on the other hand (and that's one of my main criteria) this setup is almost fail / fool proof. No mather would type of music program you would throw at it, the driver will likely never fail. Choosing a 2 tapped horn setup with the same driver (4 ohm version) with that amp, the driver would get 1200 watt's and max goes to 10 - 12 mm, still safe, but we NEED a HP filter to play real safe.
Now having said that, is there such thing as "under driven" or in number of drivers, is a 4 driver setup sounding as good / better than 2 driver setup. The 4 driver setup would add more dB due to acoustic coupling, which is a nice side effect.
I have found bass-reflex cabinets (complete different animal of-course) that start to sound "nice" when being driven above a certain level. Under that level, it feels like the contribution of the port is very limited to zero (of course the port always works, but is seems not audible (forgive my clumsy English, it's me the dutchman, he he).
Also, most systems sound "more relaxed" when being driven NOT to hard. So is there a rule of thumb for the relaxed / nice sounding area of load for a tapped horn, in % of load to a driver of that tapped horn.
Reading back my pots, forgot to mention the almost physical feel of a set of tapped horn pounding away most likely also needs a certain "minimal" drive level to start occurring. I once had the pleasure of feeling 6 TH118 driven with 8 kW of amps, DJEEEEZZ it felt like a pleasant version of , well you know what makes your boat rock.... NEVER had that with other type of cabinets before AND after.
Any comments on this question / experiences.
kind regards,
Frans
Can a tapped horn be "under driven". With that, I mean as an example, if I would choose to put say 4 keystones or SS15 with a capacity of say 4x 8 ohm / 3200 watt B&C speakers (parallel 2 pairs of 2 horn's) on a Crown amp with 2x 1200 watts on 4 ohms, each tapped horn would be loaded with max. 600 watt's (20 % of its driver capacity).
Looking in HR, the driver would have an xmax for that 600 watt load of no more than 6 - 8 mm of excursion. Even a HP filter would not be required. That would be a walk in the park, but on the other hand (and that's one of my main criteria) this setup is almost fail / fool proof. No mather would type of music program you would throw at it, the driver will likely never fail. Choosing a 2 tapped horn setup with the same driver (4 ohm version) with that amp, the driver would get 1200 watt's and max goes to 10 - 12 mm, still safe, but we NEED a HP filter to play real safe.
Now having said that, is there such thing as "under driven" or in number of drivers, is a 4 driver setup sounding as good / better than 2 driver setup. The 4 driver setup would add more dB due to acoustic coupling, which is a nice side effect.
I have found bass-reflex cabinets (complete different animal of-course) that start to sound "nice" when being driven above a certain level. Under that level, it feels like the contribution of the port is very limited to zero (of course the port always works, but is seems not audible (forgive my clumsy English, it's me the dutchman, he he
).Also, most systems sound "more relaxed" when being driven NOT to hard. So is there a rule of thumb for the relaxed / nice sounding area of load for a tapped horn, in % of load to a driver of that tapped horn.
Reading back my pots, forgot to mention the almost physical feel of a set of tapped horn pounding away most likely also needs a certain "minimal" drive level to start occurring. I once had the pleasure of feeling 6 TH118 driven with 8 kW of amps, DJEEEEZZ it felt like a pleasant version of , well you know what makes your boat rock.... NEVER had that with other type of cabinets before AND after.
Any comments on this question / experiences.
kind regards,
Frans
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The sound you like is distortion. It can sound aggressive, and give the impression of louder, but it is distortion nonetheless.Now having said that, is there such thing as "under driven" or in number of drivers, is a 4 driver setup sounding as good / better than 2 driver setup. The 4 driver setup would add more dB due to acoustic coupling, which is a nice side effect.
I have found bass-reflex cabinets (complete different animal of-course) that start to sound "nice" when being driven above a certain level. Under that level, it feels like the contribution of the port is very limited to zero (of course the port always works, but is seems not audible (forgive my clumsy English, it's me the dutchman, he he
Also, most systems sound "more relaxed" when being driven NOT to hard. So is there a rule of thumb for the relaxed / nice sounding area of load for a tapped horn, in % of load to a driver of that tapped horn.
So no, having more cabinets at lower drive level will distort less. I think that's a good thing, but I guess if you LIKE distortion you won't be getting it.
The thing is tapped horns don't quite sound the same in distortion as bass reflex boxes do. Whether it's better or worse is hard to say.
Honestly I wouldn't even spent any time thinking about it. More cabinets at lower level is always better than fewer cabinets at higher level. Also, regardless of how low you plan to drive the subs, I'd use highpass filters regardless.
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when your average level is 20dB below your maximum signal level, then you are listening to a signal that is 10% of the maximum signal level.
Take a normal 100W amplifier playing into a 100W speaker.
We have an average listening level of 1W (-20dB) and the speaker is receiving that 1W average. It sees a signal that is only 10% of the maximum input allowed.
This is the way we listen much of the time.
Now multiply those power levels by 10, or 20, or 30 and you still end up with average levels of -20dB ref maximum level uses just 10% of the speakers signal handling capability.
Except at LF. The speaker's power handling at LF is rarely equal to it's mid band capabilities. It's at LF that you are likely to overstroke your drivers. Torn surrounds and bashed voice coils.
Take a normal 100W amplifier playing into a 100W speaker.
We have an average listening level of 1W (-20dB) and the speaker is receiving that 1W average. It sees a signal that is only 10% of the maximum input allowed.
This is the way we listen much of the time.
Now multiply those power levels by 10, or 20, or 30 and you still end up with average levels of -20dB ref maximum level uses just 10% of the speakers signal handling capability.
Except at LF. The speaker's power handling at LF is rarely equal to it's mid band capabilities. It's at LF that you are likely to overstroke your drivers. Torn surrounds and bashed voice coils.
Hi Y'all,
Post #2122: "...the SS15 is not a 40hz subwoofer..."
Correct, it wasn't meant to be.
Post #2123: "...sensitivity is what we CANNOT lack here..."
Well, it's always a trade-off. If you have enough power, and don't mind loosing a little SPL in the very low end, you can put a B&C 18SW115 into the SS15.
And, you could redesign the throat area, and end up w/ a little bit more compression for the 18SW115, and a bit more duct length (not enough to matter). The 3015 does not take kindly to additional throat compression, but the 18SW115 is so robust, it can take it even at much higher power.
Don't forget the HP (high pass / low cut) filter.
Regards,
Post #2122: "...the SS15 is not a 40hz subwoofer..."
Correct, it wasn't meant to be.
Post #2123: "...sensitivity is what we CANNOT lack here..."
Well, it's always a trade-off. If you have enough power, and don't mind loosing a little SPL in the very low end, you can put a B&C 18SW115 into the SS15.
And, you could redesign the throat area, and end up w/ a little bit more compression for the 18SW115, and a bit more duct length (not enough to matter). The 3015 does not take kindly to additional throat compression, but the 18SW115 is so robust, it can take it even at much higher power.
Don't forget the HP (high pass / low cut) filter.
Regards,
Attachments
While the peak output in dance music is about 55hz, you must be able to put out 40hz with authority.
While my systems are flat to 30hz, I pay a size penalty (24H x 36W x 30D) for the one or two songs a night that go below 40hz.
Two cabinets stacked are 107dB/2.83V/1M and a 4Ω minimum load (around 30hz).
While my systems are flat to 30hz, I pay a size penalty (24H x 36W x 30D) for the one or two songs a night that go below 40hz.
Two cabinets stacked are 107dB/2.83V/1M and a 4Ω minimum load (around 30hz).
Hi again,
Just for the fun of it, here is the SPL from the Hornresp Wizard using "throat compensation", and the B&C 18SW115. It can be safely assumed, that this driver will take program peaks around 3kW instead of the Pnom=1.7kW. Not so sure if the 1/2" plywood will take it.
Regards,
Just for the fun of it, here is the SPL from the Hornresp Wizard using "throat compensation", and the B&C 18SW115. It can be safely assumed, that this driver will take program peaks around 3kW instead of the Pnom=1.7kW. Not so sure if the 1/2" plywood will take it.
Regards,
Attachments
Only took me a few years to have the epiphany about PPSL. I always wondered the benefits of reducing odd order distortion was since we all know the even order is the good stuff. It is because when the odd is reduced the even remains. Like duh. That sounds pretty incredible since I know what that sounds like.
Andrew,
Excessive excursion can indeed tear up a light cone like the 3015 LF.
Bashed voice coils are also possible on poorly designed loudspeakers.
Loudspeakers in general handle far more power at lower frequencies due to the "air pumping" at high excursion removing heat from the voice coil and magnet assembly. The exception to that rule is at Fb, where the cone, and voice coil's movement is at it's minimum, while impedance is lowest, the speaker "draws" the most power at exactly the same frequency it moves the least- add a droning bass line at that frequency, and you have the recipe for "magic smoke"
.The DJ that let out the magic smoke will then write in "I had a limiter to "protect" my sub, why did they blow?", not understanding that he further compressed his already compressed-to-shite music to a higher average power level than if he had been playing sine waves at amp clipping level
.Cheers,
Art
40 Hz Extension
Hi,
As to 40Hz extension, here is a note by jbell that some may have overlooked (I sure forgot about it):
Post #1499: "...a bit of 'S2 cone correction' instead of a compression plate.
1" taller and 1" narrower...and the SS15 can now hit with authority an honest to goodness 40hz."
Regards,
Hi,
As to 40Hz extension, here is a note by jbell that some may have overlooked (I sure forgot about it):
Post #1499: "...a bit of 'S2 cone correction' instead of a compression plate.
1" taller and 1" narrower...and the SS15 can now hit with authority an honest to goodness 40hz."
Regards,
Oliver,
Unfortunately, jbell gave no measurement of what the SPL level of the 40 Hz "authority" is, and as you know, make the same size box go lower, and it looses some of it's "authority".
Honest to goodness, let's figure out how much a 4" (or so) path length increase makes on Fb
. As Mr. Bell said long before that, if you want loud, use the SS15, if you want low from a single sheet, use the WS 2xLab 12".
One inch "authority", a GI Joe doll is like King Kong...
Art
I built 4 of those design a few years back. I never took measurements either, but they sounded good. 4015lf loaded, loud as hell. I could bridge an NU3000DSP into a pair of them and the amp would surrender before the subs, shutting off if you had the power supply stage pegged for too long. That was back when Eminence rated the 4015lf for 700w rms. They now rate it for 1200w. Not sure if they've changed the way they build them. It's safe to say you've used up all the linear excursion and then some by the time you reach those levels, but you can do it.
So if you want to make a shitload of noise for minimal money, I don't know if there's any better combo than a pair of 4015lf, a pair of ply sheets (I used 3/4"), and an NU3000DSP.
Anyways, "hit 40hz with authority" they most definitely do not. They'll play it, but not very loudly. I can say for sure they will hit 50hz with authority, though. Had a party where "A Milli" came on after some tracks that were a bit light on bass, and the subs were turned up. When the bassline came in it scared the **** out of everybody. You'll notice that the regular SS15 has actually rolled off a nontrivial amount by 50hz, so it's certainly a bit of an improvement.
Anyways, now that I've built subs that reach comfortably down to 35hz, I won't be going back. That's the kind of bass that really makes me smile. It seems like even though you lose sensitivity, the lower bass can give the impression of more powerful subwoofers at lower levels.
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Ref.: Post #1499
Hi zettairyouiki,
Post #2136: "I built 4 of those design..."hit 40hz with authority" they most definitely do not...now that I've built subs that reach comfortably down to 35hz, I won't be going back...the lower bass can give the impression of more powerful subwoofers at lower levels." (Please, see Post for full text.)
I have found it difficult to get information as to what others think about what performance is necessary at the low end.
I get 124.9dB @ 80 Hz, and 120.3 @ 40 Hz, in a similar box (increased H to 31", and kept W and D, used cone compensation), the 4015LF reaches Xmax @ 450W in the simulation, that's a drop of 4.6dB (this is not measured, simulation only).
So I find it to be very valuable information, that there is such a big practical/subjective difference between the extended SS15 and "subs that reach comfortably down to 35hz" (about -3dB @ 35Hz ? / are you talking about the Keystones?).
Regards,
Hi zettairyouiki,
Post #2136: "I built 4 of those design..."hit 40hz with authority" they most definitely do not...now that I've built subs that reach comfortably down to 35hz, I won't be going back...the lower bass can give the impression of more powerful subwoofers at lower levels." (Please, see Post for full text.)
I have found it difficult to get information as to what others think about what performance is necessary at the low end.
I get 124.9dB @ 80 Hz, and 120.3 @ 40 Hz, in a similar box (increased H to 31", and kept W and D, used cone compensation), the 4015LF reaches Xmax @ 450W in the simulation, that's a drop of 4.6dB (this is not measured, simulation only).
So I find it to be very valuable information, that there is such a big practical/subjective difference between the extended SS15 and "subs that reach comfortably down to 35hz" (about -3dB @ 35Hz ? / are you talking about the Keystones?).
Regards,
Hi tb46,
For clearance, are you talking about the SS15 V2 from Jbell?
The 27cm extender for the SS15 in a dual-SS15-configuration is -6.5 dB @ 40Hz.
Regards,
Djim
Hi djim,
Post #2138: "...are you talking about the SS15 V2 from Jbell?..."
As I said in Post #2137: "...a similar box (increased H to 31", and kept W and D, used cone compensation)...".
This was stuff I have worked on now and then; it started w/ stuffing an 18" woofer into the SS15, which requires a slight overhang into the vertical back duct. Then I added the "cone compensationd w/ additional compression. Seems to sim just fine w/ 15" and 18" drivers (some good, some bad, as always). See the response w/ a 18SW115 in Post #2130.
In the process of "upgrading to the newer and much better Microsoft Windos 10" I lost some of my AkAbak stuff. It is only my guess, but MS is still working on a way to make the rest of my old software unusable... They are doing a fine job, "honor where honor is due". AkAbak now resides on Win XP in VMware... I have not redone the AkAbak simulation for this one, and I think I'll change the external dimensions one more time.
Regards,
Post #2138: "...are you talking about the SS15 V2 from Jbell?..."
As I said in Post #2137: "...a similar box (increased H to 31", and kept W and D, used cone compensation)...".
This was stuff I have worked on now and then; it started w/ stuffing an 18" woofer into the SS15, which requires a slight overhang into the vertical back duct. Then I added the "cone compensationd w/ additional compression. Seems to sim just fine w/ 15" and 18" drivers (some good, some bad, as always). See the response w/ a 18SW115 in Post #2130.
In the process of "upgrading to the newer and much better Microsoft Windos 10" I lost some of my AkAbak stuff. It is only my guess, but MS is still working on a way to make the rest of my old software unusable... They are doing a fine job, "honor where honor is due". AkAbak now resides on Win XP in VMware...
I have not redone the AkAbak simulation for this one, and I think I'll change the external dimensions one more time.Regards,
Yes, the fact that it only takes about a 5 dB difference in level at 40 Hz to sound "twice as loud" makes a little bit of extension go a long way.
I'm really excited about building the new "B-Low" Keystones with around 29 Hz Fb, a bit bigger, a bit less loud, but a LOT lower.
Art