Ok looks like we're on the something.
im heading out for the night. when i get back. i'll model up some boxes with 4 12 dayton HO's
am i right by sayin i am gaining 9 decibels by using 4 drivers instead of one?
i was lead to believe that one parralell connection will double the current, therefore doubling the sensitivity.
so 2 parralell connections = 12 db of gain.
minues 3 decibels because of a series connection.
i spoose that maybe you only get 3 decibels from doubling the current, and the other 3 comes from adding twice the cone area.making 6 db of gain
somene correct me if im fro
im heading out for the night. when i get back. i'll model up some boxes with 4 12 dayton HO's
am i right by sayin i am gaining 9 decibels by using 4 drivers instead of one?
i was lead to believe that one parralell connection will double the current, therefore doubling the sensitivity.
so 2 parralell connections = 12 db of gain.
minues 3 decibels because of a series connection.
i spoose that maybe you only get 3 decibels from doubling the current, and the other 3 comes from adding twice the cone area.making 6 db of gain
somene correct me if im fro
I won't comment on the amp values (but you're probably on the right lines) as not all amps will do this; but everytime you double cone area you double SPL which means a 3dB increase. if your amp decides to increase power delivery on a lower impedance value, all the better - but beware of making the whole lot sound strained and wrecked by making the amps deliver what they can't (common night club faux pa!).
Hmm...
First off, you say you want a sub that will put "GOBS" of bass onto the dance floor, more than JBL, EV, etc, etc, but then you say the sub doesn't need to go any lower than about 45Hz. I have news for you, 45Hz is not GOBS of bass for night clubs.
I don't know what kind of night clubs you have up there in New Brunswick, but ALL of the night clubs here in Florida that I've been in have serious output to at least 20Hz. I know for a fact because I know all of the music they play very very well.
And secondly, using the room for "corner" loading would be highly impractical due to the fact that most clubs do NOT place their subs anywhere near walls or room boundaries. A lot of the clubs use groups of 2 or 4 bass bins on either side of the dance floor, or some even use a couple single and small bass bins out in the middle of the floor, which the girls use to dance on. (I always find myself standing next to those for some reason! huba, huba, huba... .
Anyway, in order to make any of this happen, you're going to have to use drivers with large 3" or 4" voice coils that are capable of sustained high temperatures for 8 to 10 hours straight, and are capable of high SPL levels at frequencies well below your 45Hz.
The only thing I could see you doing (cost wise) is to try and match the performance of the big companies, but for a fraction of the cost.
That's just my 2 cents.
First off, you say you want a sub that will put "GOBS" of bass onto the dance floor, more than JBL, EV, etc, etc, but then you say the sub doesn't need to go any lower than about 45Hz. I have news for you, 45Hz is not GOBS of bass for night clubs.
I don't know what kind of night clubs you have up there in New Brunswick, but ALL of the night clubs here in Florida that I've been in have serious output to at least 20Hz. I know for a fact because I know all of the music they play very very well.
And secondly, using the room for "corner" loading would be highly impractical due to the fact that most clubs do NOT place their subs anywhere near walls or room boundaries. A lot of the clubs use groups of 2 or 4 bass bins on either side of the dance floor, or some even use a couple single and small bass bins out in the middle of the floor, which the girls use to dance on. (I always find myself standing next to those for some reason! huba, huba, huba... .
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)
Anyway, in order to make any of this happen, you're going to have to use drivers with large 3" or 4" voice coils that are capable of sustained high temperatures for 8 to 10 hours straight, and are capable of high SPL levels at frequencies well below your 45Hz.
The only thing I could see you doing (cost wise) is to try and match the performance of the big companies, but for a fraction of the cost.
That's just my 2 cents.
Here's the general idea; multiple driver arrangement - rear bottom edge porting. Where the driver is set against a wall you get a small degree of horn accentuatin; where you don't, you get a standard rear ported (will sound "cleaner") bass reflex enclosure. Might pay dividends to slope the baffle backwards - if stacking isn't an issue, make it a "tobelerone". In the diagram, I've shown two stacked drivers; in reality you'd stick 'em side by side to give a wider horn. You can also lift the base at the front and slope the back away from the wall, although this might detract from the deepest bass: experiment!
What do you think?
What do you think?
What music do you know very well? Are we talking the latest ludacris nelly chris brown lil jon 50cent kanye west or whoever else clear channel chooses to overplay and has a not so overly girlish rap beat and lyrics. Cuz none of that stuff has anything much below 30hz.
Even the so called "multi-million dollar" clubs around here and in st louis lack much authority at 30hz compared to some parts of the spectrum. I will say most of the better clubs have systems that get that low, but I know they're down at least a few decibels.
However when you get a sub that can put out 120db @30hz and 144db@45hz one meter away, the 30hz output may be significantly attenuated, but it is still easily heard and felt.
BassAwdyO said:
Well, if it helps any, I don't any of those freaks you mentioned. I am in NO WAY remotely interested in any rap or hip-hop garbage.
The clubs that I go to are in the hart of major cities such as Tampa, Orlando, Daytona, and sometimes even Gainsville, Jacksonville and on very rare occations, Tallahassee. Heck, we've even gone out of state to Atlanta, GA for several concerts at night clubs.
And for the music I listen to, it's usually "dark" industrial-goth music, and a LOT of it comes fresh straight from the bands with plenty of sub-30Hz and sub-20Hz bass in it these days.
CHOPS
the only music i've ever heard thats as low as 20 hz is bands that have likea 7 string bass. how many clubs have to been to that have this kind of instrument driving a dance floor?
all rap musics kick is ever usualy below 30HZ, its rare to be lower but i find it sometimes.
all the bass in night clubs is usually right at 40 hz sometimes even 50, in fact 40 hz is the loudest frequency. one octave above the threshold of hearing. Most people are blown away by a 40 hz test because they THINk* its low. its just that they've never heard anything so loud. people like you n me know the difference.
i only said the dj's around here use a 45 hz cut off. i want powerfull linearity to 35.
anyways, thanks for you 2 cents.
Linkletter.
the only music i've ever heard thats as low as 20 hz is bands that have likea 7 string bass. how many clubs have to been to that have this kind of instrument driving a dance floor?
all rap musics kick is ever usualy below 30HZ, its rare to be lower but i find it sometimes.
all the bass in night clubs is usually right at 40 hz sometimes even 50, in fact 40 hz is the loudest frequency. one octave above the threshold of hearing. Most people are blown away by a 40 hz test because they THINk* its low. its just that they've never heard anything so loud. people like you n me know the difference.
i only said the dj's around here use a 45 hz cut off. i want powerfull linearity to 35.
anyways, thanks for you 2 cents.
Linkletter.
Jezz. its a good idea for a permanent install. but dj's are just to picky with easy of use issues. alot of dj's will sacrafice quality for light cabinets and other things that make it easier to work with. night clubs and churches tend to have alot more flexibility.
i've got a couple idea tho/
what if the sub was ported into a slot at the bottom of the box. with the back sealed off and the slow pointing at the croud.
Could any relevant output be gained by doing that?
i've been modeling subs all night. the dayton 18 is out of the question. it takes 4 of them to equivelate 2 kilomax 18's
4 dayton dvc 12's will stay right along side the 18's in 5 cubic feet less then the 18's.
I think the DVC's are the best bet. so heres my proposal.
4 dayton dvc 12's.
thats 8 coils at 8 ohms. 2 banks of 3 parralel connections (4 woofers) to get two banks at 2 ohms. then series to bring back to 4.
6 parallel connections =36 db of gain.
1 series = -3 db loss.
33 db gain in sensitivity.
and all pro sound amps will run at 4 ohms
i see NO other drivers on the market period that will do what these will in 10 cubic feet
Anehoic spl chart
HZ DB
20 104
25 115
30 123
35 128
40 130
45 130
50 130
10 cubic feet tuned to 34 hz with an f3 of 32.
i do believe that output above 140 is possible with the right placement.
ok, now lets get workin on some ways to design the box to improve output
i've got a couple idea tho/
what if the sub was ported into a slot at the bottom of the box. with the back sealed off and the slow pointing at the croud.
Could any relevant output be gained by doing that?
i've been modeling subs all night. the dayton 18 is out of the question. it takes 4 of them to equivelate 2 kilomax 18's
4 dayton dvc 12's will stay right along side the 18's in 5 cubic feet less then the 18's.
I think the DVC's are the best bet. so heres my proposal.
4 dayton dvc 12's.
thats 8 coils at 8 ohms. 2 banks of 3 parralel connections (4 woofers) to get two banks at 2 ohms. then series to bring back to 4.
6 parallel connections =36 db of gain.
1 series = -3 db loss.
33 db gain in sensitivity.
and all pro sound amps will run at 4 ohms
i see NO other drivers on the market period that will do what these will in 10 cubic feet
Anehoic spl chart
HZ DB
20 104
25 115
30 123
35 128
40 130
45 130
50 130
10 cubic feet tuned to 34 hz with an f3 of 32.
i do believe that output above 140 is possible with the right placement.
ok, now lets get workin on some ways to design the box to improve output
i need help deciding if the ports i've selected would be appropriate.
10 cubic feet tuned to 33 hz
i want to put (8) 4" wide 22" long ports which will allow the system to handle over 2 kw and never exceed 30 m/s air velocity.
8 4 inch ports to me sounds like it would open up some SERIOUS air movement and with hardly any port noise shoudl sound excellend.
More ideas are welcomed. i want to make every aspect of this box PERFECT before i even build itl
10 cubic feet tuned to 33 hz
i want to put (8) 4" wide 22" long ports which will allow the system to handle over 2 kw and never exceed 30 m/s air velocity.
8 4 inch ports to me sounds like it would open up some SERIOUS air movement and with hardly any port noise shoudl sound excellend.
More ideas are welcomed. i want to make every aspect of this box PERFECT before i even build itl
You are a bit wrong on the sensivity thing.
You use 4 drivers rated at 90.4 dB sensivity at 2.83V.
90.4 dB with one driver.
You double the cone area so 93.4 dB with two drivers (+3 dB).
You double again so 96.4 dB with four drivers (+3 dB).
You had 4 ohms at the start. You end up with 4 ohms at the end. No sensivity changes.
So your group of drivers got a sensivity of 96.4 dB/1m/2.83V RMS.
You are also at 93.4 dB/1m/1W efficiency.
Sorry to break the fun a bit.
Nothing can beat a horn for stuff over 30-40 Hz.
Ported is not a bad idea, but look at Pro drivers, not those Dayton DVCs.
You use 4 drivers rated at 90.4 dB sensivity at 2.83V.
90.4 dB with one driver.
You double the cone area so 93.4 dB with two drivers (+3 dB).
You double again so 96.4 dB with four drivers (+3 dB).
You had 4 ohms at the start. You end up with 4 ohms at the end. No sensivity changes.
So your group of drivers got a sensivity of 96.4 dB/1m/2.83V RMS.
You are also at 93.4 dB/1m/1W efficiency.
Sorry to break the fun a bit.
Nothing can beat a horn for stuff over 30-40 Hz.
Ported is not a bad idea, but look at Pro drivers, not those Dayton DVCs.
Hi Jaden
by my reckoning 30 m/sec is too high for 4in ports - you would need 50mm flares each end to keep 'em quiet.
Peak flow for 8 ports is around 2000 litres / sec, which can be achieved with 4 * 6 inch ports running at around 28 m/sec. - They'll want 30mm flares each end, which you can still get.
This is based on extrapolating results of testing on smaller diameter ports. Others out there may have experience with six inch ports at these sorts of speeds.....
regards
Collo
by my reckoning 30 m/sec is too high for 4in ports - you would need 50mm flares each end to keep 'em quiet.
Peak flow for 8 ports is around 2000 litres / sec, which can be achieved with 4 * 6 inch ports running at around 28 m/sec. - They'll want 30mm flares each end, which you can still get.
This is based on extrapolating results of testing on smaller diameter ports. Others out there may have experience with six inch ports at these sorts of speeds.....
regards
Collo
simon5 said:
I was thinking the same exact thing, but a lot of people around here tend to think that I never know what I'm talking about, including night clubs with 20Hz bass capabilities.
But hey, what do I know. I've only been dealing with audio equipment for the past 20+ years of my life.
Hoffman's Iron Law: The three parameters are Size, Efficiency, and LF Extension. You can only control two, and the third are controlled by the other two.
For professional audio, the order of importance is always: Small Size, High Efficiency, LF Extension.
Have you considered a triple-15" design? Peavey has an interesting new long throw professional 15" called the LowMax or something like that. A good triple-15 design can be shoehorned into a box normally used for a dual-18" design. Three 8-ohm 15" woofers will give a 3.2 ohm load, and some very beefy amplifiers like Crown Macrotech will bridge into that safely.
For professional audio, the order of importance is always: Small Size, High Efficiency, LF Extension.
Have you considered a triple-15" design? Peavey has an interesting new long throw professional 15" called the LowMax or something like that. A good triple-15 design can be shoehorned into a box normally used for a dual-18" design. Three 8-ohm 15" woofers will give a 3.2 ohm load, and some very beefy amplifiers like Crown Macrotech will bridge into that safely.
For a portable system for DJs, then I personally see no need to go below 40Hz at the -6dB level. The punters won't know the difference, you'll need half the amp power, and the kit will be smaller, lighter and cheaper. Stick any DJ in front of two boxes, one flat down to 20Hz, and the other rolling off at 40Hz, with a bit of boost at the chest resonance frequency of 60-80Hz, and I'll put money on which they go for.
Heres my theory.
a single parrallel connection with cut your inductance by half, if this is true, that would mean it doubles your sensitivity.
by doing this there also must be doulbe the cone area. so another 3 db.
(4) 4 ohm drivers. 2 parralell connections and one series connection = 9 db of gain on top of the already 90 db sensitive drivers. so the drivers will now be almost 100 decibels sensitive at 2.83V
For every doubling of the drivers you'll get +3dB in sensitivity. So four drivers are 6 dB over one. Next to that you'll have another 6 dB more over one, by having 4 times the powerhandling.
If you're going for basreflex 15" or 18" would be the way to go, 12" basreflex just wouldn't give the desired SPL or sensitivity. An 18" aimed for 45 Hz and up in a relatively small enclosure (6,2 cubic ft) is the Beyma 18G50.
Still I would consider hornloaded like a tuba 24 or a Punisher. The Punisher is sligthly difficult to build but the high sensitivity (102 - 103 dB/W/m) combined with the 1500 W powerhandling gives a respectable SPL for 45 -50 Hz up to 100 Hz.
Btw don't forget about powercompression.
Wkr Johan
It doesn't have to be true but a good 18" pro woofer will offer around 97 dB/W/m.
If you're going for basreflex 15" or 18" would be the way to go, 12" basreflex just wouldn't give the desired SPL or sensitivity. An 18" aimed for 45 Hz and up in a relatively small enclosure (6,2 cubic ft) is the Beyma 18G50.
Still I would consider hornloaded like a tuba 24 or a Punisher. The Punisher is sligthly difficult to build but the high sensitivity (102 - 103 dB/W/m) combined with the 1500 W powerhandling gives a respectable SPL for 45 -50 Hz up to 100 Hz.
Btw don't forget about powercompression.
Wkr Johan
Yes you could plug all of them in parallel.
90.4 dB in parallel with 90.4 you'll get 96.4 dB. (+3 dB parallel and +3 dB cone area doubling)
Now, you have two pairs of drivers at 96.4 dB.
96.4 dB in parallel with 96.4 you'll get 102.4 dB.
Yes, you're right, you get now 102.4 dB/1m/2.83V RMS.
Now, the problem is, you got a 1 ohm load.
A 4 ohms driver in parallel with another one will give 2 ohms.
Then the two pairs at 2 ohms each in parallel will give 1 ohm.
Very few power amplifiers can drive a 1 ohm load.
To counter this, you connect the two pairs at 2 ohms in series instead of parallel. You now got a 4 ohms load.
Parallel = +3 dB sensivity
Series = -3 dB sensivity
102.4 - 6 = 96.4 dB
Why -6 ? You lose the +3 dB because they are no longer in parallel and you gain -3 dB because they are in series now.
I'll do this part slower now to show what's happening.
Disconnect the two last pairs.
You get two pairs of drivers at 2 ohms.
They got 96.4 dB sensivity each.
Plug the pairs in parallel to get a 1 ohm load = 102.4 dB sensivity
Plug the pairs in series to get a 4 ohms load = 96.4 dB + 3 dB = 99.4 dB because cone area is doubled - 3 dB = 96.4 dB because they are in series now.
Result = 96.4 dB efficiency
90.4 dB in parallel with 90.4 you'll get 96.4 dB. (+3 dB parallel and +3 dB cone area doubling)
Now, you have two pairs of drivers at 96.4 dB.
96.4 dB in parallel with 96.4 you'll get 102.4 dB.
Yes, you're right, you get now 102.4 dB/1m/2.83V RMS.
Now, the problem is, you got a 1 ohm load.
A 4 ohms driver in parallel with another one will give 2 ohms.
Then the two pairs at 2 ohms each in parallel will give 1 ohm.
Very few power amplifiers can drive a 1 ohm load.
To counter this, you connect the two pairs at 2 ohms in series instead of parallel. You now got a 4 ohms load.
Parallel = +3 dB sensivity
Series = -3 dB sensivity
102.4 - 6 = 96.4 dB
Why -6 ? You lose the +3 dB because they are no longer in parallel and you gain -3 dB because they are in series now.
I'll do this part slower now to show what's happening.
Disconnect the two last pairs.
You get two pairs of drivers at 2 ohms.
They got 96.4 dB sensivity each.
Plug the pairs in parallel to get a 1 ohm load = 102.4 dB sensivity
Plug the pairs in series to get a 4 ohms load = 96.4 dB + 3 dB = 99.4 dB because cone area is doubled - 3 dB = 96.4 dB because they are in series now.
Result = 96.4 dB efficiency
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