Thanks for the horn resp oliver, however I think to make a real comparison, excursion plots need to be added.
The stadium horn I will only run up to 50v, and the ss15 I feel comfortable running up to 63v.
Of course size must also be considered, and the big box is 2.5 times as big as the ss15, and right at 3 times the weight.
Big box for install, or for those really low notes... ss15 for everything else in my book. (I also attached a packspace comparison 5 ss15 vs a pair of stadiumhorn for those who are space restricted....)
The stadium horn I will only run up to 50v, and the ss15 I feel comfortable running up to 63v.
Of course size must also be considered, and the big box is 2.5 times as big as the ss15, and right at 3 times the weight.
Big box for install, or for those really low notes... ss15 for everything else in my book. (I also attached a packspace comparison 5 ss15 vs a pair of stadiumhorn for those who are space restricted....)
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Shawn:
5 is kinda an odd number, I only picked that as a pack space vs pack space comparison. Where the stadiumhorn is 2.5 times as big -- 2 vs 5 was the obvious choice for the comparison.
Here's a quad ss15 vs a quad stadiumhorn.
They both fulfill their need, the get loud in quads... The stadiumhorn just gets louder lower.
Remember I measured 114db@40hz sine wave @20v per cabinet @ 10meters with a quad of stadium horns. That's some serious Woof.
Hornresp is not predicting that much... so I believe the directivity of a quad of stadium horns is at play in that measurement
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Jim,
The sim in #422 shows 40 Hz at 102 dB for a single stadium horn.
Four stadium horns should be 114 dB (+6 dB increased sensitivity for quadrupling cone area, +6 for quadrupling power), exactly what you measured, no directivity required.
At 1000 hz, an increase of 10 dB sounds twice as loud.
An interesting perception shift occurs down low, at 20 Hz it only takes a 5 dB increase to sound twice as loud.
+12 at 30-40 Hz is hard to ignore, the lower the speaker goes, the “louder” it sounds.
Hornresp models TH as having a lower LF corner in multiples. Multiple FLH do have a decreasing LF corner in multiples, like BR cabinets, tapped horns do not, as Tom Danley has stated and explained in multiple posts. Plots of multiple TH-15, in one, two , and four actual measurements show hardly any change in the LF corner.
I am grateful for such a powerful freeware program as Hornresp, the LF corner detail is no consequence for the usual DYI build using one or two units indoors, where rooms make nonsense of actual speaker response.
However, it is an important consideration for those of us accustomed to the FLH low corner going down in multiples, it does not happen with TH, even though the +6 or 12 dB from doubling and quadrupling cabinets frequently leads to the mistaken impression it does.
If you review your actual measurements you will probably very little LF corner change in four SS15 or Stadium horns, other than that which would result from the driver’s Fs dropping by a couple Hz going from a single to four, this same effect happens with BR cabs.
As an example EVX-150 single, 35 FS, two in close proximity, 34 Hz, four 32.5Hz Fs.
QTS goes from .251 to .27.
Art
Art:
2.83v compared to 20v is what?
so you have hornresp up and running?
what is 4 stadiumhorn cabinets at 20v in 2pi show for 1meter response?
Yes, I finally have Hornresp running, am at the initial crawl stages of learning to do with a program what I have done with a calculator, paper and sawdust since 1973
. Probably could have saved a few trees along the way if I had been using the program
.Trying to think in metric instead of inches and feet, using Windows instead of Mac OS (99.9% of my work has been on Macs), and catching up on hundreds of pages of posts and charts I missed while on a dial up connection have made for a steep learning curve with lots of overload for this old dog
.I don’t know what Hornresp says 4 stadiumhorn cabinets at 20v in 2 pi show for 1 meter response, but would be interested to see how it compares to your build results.
Sorry, missed that you measured at only 20 V, 50 watts per eight ohm speaker rather than the usual 28.3 volt,100 watts per speaker which results in a 10 meter measurement equivalent to a 1 meter measurement at 2.83 v.
If the measurement of four cabinets (each driven with the same voltage) is indeed more than 12 dB higher than a single cabinet, it would indicate forward gain due to:
1. A larger plane surface, like the “wings” used with old Altec theater horns, increases LF, they behave as a horn extension, and also as a larger plane, a frequency dependent transition from half space to quarter space.
The larger “non-horn”, flat front portion of a TH cabinet is a continuation of the horn, and a partial transition to quarter space.
That portion of the horn would require some clever input in Hornresp to simulate properly, and would require a different input for 1, 2, 4 or more cabinets to actually sim correctly.
2. A lower LF corner due to the mouths coupling, which I consider unlikely, as Tom Danley has explained due to the small mouth size. This occurs in Hornresp for TH, though it should probably be ignored.
3. A lower LF corner due to the speakers FS dropping due to their close proximity, which I assume should happen in TH as it does in BR cabinets.
4. All of the above behave synergistically, isolation of the three would require some rather extensive testing .
MAPP online pro, a free sim from Meyers, could "sort of" be used to model the directivity at different frequencies due to a larger plane, one can simply space a pair (or any number) of speakers wider, similar to what happens in any LF array and see the radiation changes that occur in a half space environment, with or without walls.
Curious why you measured at 20V instead of 28.3V?
What did a single cabinet measure at at 40 Hz, 20v, 10 meter, compared to four ?
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1 cabinet measured 102db@40hz 2.83v@1m, exactly as hornresp said it should. I went from there straight to a 10meter 4 cabinet test.
As for the 20v, I was standing in front of the d@#@# thing while turning it up.... My meter leads aren't that long.... and I didn't think even with hearing protection that I should go for 28v, which was my intention....
As for the 20v, I was standing in front of the d@#@# thing while turning it up.... My meter leads aren't that long.... and I didn't think even with hearing protection that I should go for 28v, which was my intention....
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Oh well, it would be nice to have compared apples to apples (20 v 1 vs 4) to see how much the change from one to four was.
It could be three dB (plus the expected 12 dB), or not- your one meter 1 watt tests don’t match exactly to your ten meter 100 watt tests (not that they should).
I personally am not worried about hearing damage from LF under 60 Hz, for short duration.
Astronauts are subjected to around 160 dB of LF noise on takeoff, if it caused hearing damage, they would all be deaf.
Same goes for all the fliers who have spent countless hours subjected to helicopter and various aircraft LF well in excess of 120 dB, hearing protection does little to attenuate LF, even if it were worn.
Muffs (deadphones) can actually make certain LF frequencies louder, due to the cavity resonance of the enclosed volume under the phone.
I do wish I had worn more hearing protection when exposed to industrial noise and music when I was young, I don’t recall any hearing protection at all in high school shop class
.Absolutly right there Art: Guidelines for safe enduring Peak Impulses (not specified in time/freq domain) within a day:
100 peak impulses of 140dB
1,000 peak impulses of 130dB
10,000 peak impulses of 120dB
weltersys; said:
and those astronauts do endure these high sound levels as part of vibrations. More detailed: transient vibrations (<80Hz), random vibration (20-2000Hz), pyro-technique shock vibrations (100-10,000Hz). That's the reason why you still can hear relative low level sounds from in the cabin during launching (from the cabine microphone which is part of the sound level monitoring safety system and what you can hear in the videolink from below).
LiveLeak.com - What the Space Shuttle Crew feels at Liftoff
Confused re. flat to 40
JBELL, You say that a set of 4 SS15 should be flat to 40 Hz, at 140 dB.
However, on your chart for 4 SS15, the output falls from 50 Hz (approx 140dB) down to 40 Hz (approx 135 dB)
Can this response safely be EQed flatter? Or is there a big difference between the calculated and measured response?
BTW, 140 dB would be awesome. Due to the tiny size of the SS15, I could load / pack them much more efficiently than the Stadium horns - probably up to 8 without losing much space compared with the 2 big uns! Not sure if it is worth making more than 4 of them - 8 SS15 would give me only 3 more dB due to a doubled cabinet count?
Regards, Ben
JBELL, You say that a set of 4 SS15 should be flat to 40 Hz, at 140 dB.
However, on your chart for 4 SS15, the output falls from 50 Hz (approx 140dB) down to 40 Hz (approx 135 dB)
Can this response safely be EQed flatter? Or is there a big difference between the calculated and measured response?
BTW, 140 dB would be awesome. Due to the tiny size of the SS15, I could load / pack them much more efficiently than the Stadium horns - probably up to 8 without losing much space compared with the 2 big uns! Not sure if it is worth making more than 4 of them - 8 SS15 would give me only 3 more dB due to a doubled cabinet count?
Regards, Ben
sorry ben, haven't checked in for a little bit -- wasn't ignoring you.
I really want a bit more 40hz out of these as well as everyone else... however it is a see-saw, more low, less loud... hmm..
I posted awhile back my thought on getting a tiny bit lower, when it gets a little warmer I'll have to try that and see what it does. It shortens the cabinet to 29" instead of 30" tall but it does get about 10cm longer path.. so who knows exactly how much it'll help
As long as you have a 48db/oct LR high pass at 40hz, yea you can add a little 45hz bump in eq to flatten things out without causing issues. I have done that in my xti amps when I do installs with single cabinets, and it helps.
I personally would never want to haul the big cabinet around to gigs -- only install it and forget it.
Yes double cabinet count gets you 3db, the ability to also double power input gets another 3db. Part of the way the small cabinet really helps in the output department is that you are safe up to 63v instead of the 50v of the big cabinet.
I personally think for you it's worth building one (hey it only costs you a single sheet of plywood !!) and then comparing the big cabinet to the small cabinet and see what you see... My personal thought is that 4 of them fits in the same space as a pair of the big cabinets and gets you a BUNCH more woof.
I really want a bit more 40hz out of these as well as everyone else... however it is a see-saw, more low, less loud... hmm..
I posted awhile back my thought on getting a tiny bit lower, when it gets a little warmer I'll have to try that and see what it does. It shortens the cabinet to 29" instead of 30" tall but it does get about 10cm longer path.. so who knows exactly how much it'll help
As long as you have a 48db/oct LR high pass at 40hz, yea you can add a little 45hz bump in eq to flatten things out without causing issues. I have done that in my xti amps when I do installs with single cabinets, and it helps.
I personally would never want to haul the big cabinet around to gigs -- only install it and forget it.
Yes double cabinet count gets you 3db, the ability to also double power input gets another 3db. Part of the way the small cabinet really helps in the output department is that you are safe up to 63v instead of the 50v of the big cabinet.
I personally think for you it's worth building one (hey it only costs you a single sheet of plywood !!) and then comparing the big cabinet to the small cabinet and see what you see... My personal thought is that 4 of them fits in the same space as a pair of the big cabinets and gets you a BUNCH more woof.
Jbell, I don’t like to push anyone but you already have beaten the challenge of getting the maximum efficiency out of one sheet
. Lowering the freq will lower its Max Effectiveness in a logarithm way. Like your "hmmm" that doesn’t sound very economics vs effectiveness to me… Maybe it’s time for a new efficient/economic goal with new settings for a new 'winner' (perhaps something like: factor 1,25 in 40Hz-4cabs/5sheets or factor 1,5 in 40Hz 2cabs/3sheets)? That sounds more logarithmic to me...
More output with SS15
Just tried loading the specs for the B&C BC18SW115-4 into the 8/15/10 tb46’s Hornresp simulation of your SS15.
Hope that is the most correct sim.
It appears to work like gangbusters in your cab, though I will be building larger to go lower.
The BC18SW115 is a big honking 18”, I didn’t check dimensions to see if it would actually fit into the SS15 without some “adjustments”, did have to change the sim slightly to keep the 18” from hanging out the mouth.
I’d post the charts, but have not figured out how on a Windows machine yet.
If anyone wants to do the sims , here are the input specs for the BC18SW115-4:
Sd 1210
Bl 26.07
Cms 7.14E-05
Rms 10.77
Mmd 282.7
Le 1.36
Re 3.3
I estimate the area in front of the cone with a 3/4” baffle cut out to be about 7413 cc, so :
Vtc 7413
I am not sure what value to put in for Atc, I guessed at 881.
Large variations of Vtc and Atc don’t seem to affect the response in the LF pass band much, but do affect the above 150 Hz range.
Atc is defined as “Throat chamber average cross-sectional area normal to axis (sq cm).
Anyone have a definitive answer of how that relates to Atc in a reduced throat area TH ?
The BC18SW115-4 with 110V input sims flat at 135 dB from 50-80 Hz, rising to about 137 dB at 120Hz.
The 3015LF is about 130 dB in that range, with a bit of a droop around 100 Hz.
Appears one box loaded with the BC18SW115-4 (with more power ) should keep up with two fully powered 3015LF in the upper range. 110 V into 4 ohms is around 3000 watts, while the two 3015 would be using about 1000 watts between the pair at 63 volts.
At 40 Hz, the BC18SW115-4 is 130 dB compared to 120 dB for the 3015LF..
At 40 Hz, looks like one BC18SW115 could put out as much as three 3015LF.
Just bought a pair, have not put them in any cabinet yet, but open air tests have shown them to be Xmax and power monsters, they barely exceed the 14mm Xmax with 50 V at 11 Hz.
They are more expensive per cone, but for those that want to get the most output from a small box, a clear winner. With as much output as they are capable of, the $$ to SPL ratio actually might favor the BC18SW115, though more amplifier power will be needed to take advantage of the full SPL capability.
I don't think 1/2” plywood is thick enough too handle as much peak power as the BC18SW115 will take, though.
One thing I have noticed when comparing the BC18SW115-4 to the BC18SW115-8 is the four ohm version, being less than 1/2 the VC DCR, needs to have a 2.23 V (rather than 2V) input to be equivalent to the eight ohm version at 2.83 v.
The 18 Sound 18NLW9600-4 sims (and physically appears) very similar to the BC18SW115-4, but it’s lower DCR of only 2.5 ohms makes the 18 Sound show a higher sensitivity.
Art
Jim,
Just tried loading the specs for the B&C BC18SW115-4 into the 8/15/10 tb46’s Hornresp simulation of your SS15.
Hope that is the most correct sim.
It appears to work like gangbusters in your cab, though I will be building larger to go lower.
The BC18SW115 is a big honking 18”, I didn’t check dimensions to see if it would actually fit into the SS15 without some “adjustments”, did have to change the sim slightly to keep the 18” from hanging out the mouth.
I’d post the charts, but have not figured out how on a Windows machine yet
.If anyone wants to do the sims , here are the input specs for the BC18SW115-4:
Sd 1210
Bl 26.07
Cms 7.14E-05
Rms 10.77
Mmd 282.7
Le 1.36
Re 3.3
I estimate the area in front of the cone with a 3/4” baffle cut out to be about 7413 cc, so :
Vtc 7413
I am not sure what value to put in for Atc, I guessed at 881.
Large variations of Vtc and Atc don’t seem to affect the response in the LF pass band much, but do affect the above 150 Hz range.
Atc is defined as “Throat chamber average cross-sectional area normal to axis (sq cm).
Anyone have a definitive answer of how that relates to Atc in a reduced throat area TH ?
The BC18SW115-4 with 110V input sims flat at 135 dB from 50-80 Hz, rising to about 137 dB at 120Hz.
The 3015LF is about 130 dB in that range, with a bit of a droop around 100 Hz.
Appears one box loaded with the BC18SW115-4 (with more power ) should keep up with two fully powered 3015LF in the upper range. 110 V into 4 ohms is around 3000 watts, while the two 3015 would be using about 1000 watts between the pair at 63 volts.
At 40 Hz, the BC18SW115-4 is 130 dB compared to 120 dB for the 3015LF..
At 40 Hz, looks like one BC18SW115 could put out as much as three 3015LF.
Just bought a pair, have not put them in any cabinet yet, but open air tests have shown them to be Xmax and power monsters, they barely exceed the 14mm Xmax with 50 V at 11 Hz.
They are more expensive per cone, but for those that want to get the most output from a small box, a clear winner. With as much output as they are capable of, the $$ to SPL ratio actually might favor the BC18SW115, though more amplifier power will be needed to take advantage of the full SPL capability.
I don't think 1/2” plywood is thick enough too handle as much peak power as the BC18SW115 will take, though.
One thing I have noticed when comparing the BC18SW115-4 to the BC18SW115-8 is the four ohm version, being less than 1/2 the VC DCR, needs to have a 2.23 V (rather than 2V) input to be equivalent to the eight ohm version at 2.83 v.
The 18 Sound 18NLW9600-4 sims (and physically appears) very similar to the BC18SW115-4, but it’s lower DCR of only 2.5 ohms makes the 18 Sound show a higher sensitivity.
Art
Thanks for the tip, Oliver.
Not enjoying Windows, but learning Hornresp is fun!
With jbell reporting more LF output than your sim predicted, I'm dying to get my BC18SW115-4 cones in a box.
Still wondering about:
Atc is defined as “Throat chamber average cross-sectional area normal to axis (sq cm)."
Do you know how that relates to Atc in a reduced throat area TH, that is, an exit smaller than the cone area ?
Why did you model the SS15 with hyperbolic and exponential flares rather than a series of conical expansion as it seems to be ?
Art
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