I am thinking about an omi directional sound system (mono) and have a space 0.4x0.4x1.2m to work with for the bass unit. I would like this speaker to cover 30 - 100hz, input is a typicaly going to be very bass heavy party music (dub etc). Therfore quality is secondary to absolute output. I would prefer to minimise needed power input as I have a spare 80+80W amplifier that I would like to use one channel for the sub and one for the main/trebble.
I would like to know what kind of sub designs to look into, my woodworking skill dosen't extend to curves or angled cuts so most horn designs are out. Any ideas?
I would like to know what kind of sub designs to look into, my woodworking skill dosen't extend to curves or angled cuts so most horn designs are out. Any ideas?
yep lowest note on a bass is 41Hz so I idealy don't want any atenuation of this. If anercoic response -3dB is 30Hz then room gain should extend the response down to 20Hz. I aiming for serious trouser flapping.
having a look around at the ultra low end drivers within the student budget I have found:
http://onecall.farnell.com/pro-signal/ls00432/woofer-polyprop-cone-8ohm-12/dp/3708550
I suspect this is a rebadged skytronic woofer, I would have to mesure it to find its thile small parameters but I think 4 of these in a ported enclosure would be pretty impesive.
having a look around at the ultra low end drivers within the student budget I have found:
http://onecall.farnell.com/pro-signal/ls00432/woofer-polyprop-cone-8ohm-12/dp/3708550
I suspect this is a rebadged skytronic woofer, I would have to mesure it to find its thile small parameters but I think 4 of these in a ported enclosure would be pretty impesive.
Bigger is better, but big enough? According to Richard Small (the S in T/S), max vented box efficiency in liters for 30 Hz/F3 is: n0 = ~3.9*10^6*30^3*(480/1000) = ~5.054%, then SPL = ~112.018+(10*log10(0.05054)) = ~99.055 dB and adding in 80 W = +(10*log10(80)) = ~118.08 dB/m
Since the max size will be somewhat smaller due to box panel thickness, etc., it will of course be somewhat lower. In a large room where it will be falling with distance it will be mildly entertaining, but hardly 'trouser flapping'.
GM
Mildly entertaining?
I can't think of many in-house systems that will do that sort of thing.
I'd strongly advise going for something a little more rugged than a hifi replacement driver. Think PA gear. There's much more efficiency on offer, and they're designed to be played loud for some time.
What SPL are you looking for?
You'll need something of high efficiency to go half-serious (120dB) with 80W.
I would expect that a single (or two) 18" drivers would easily out perform the 12" woofers you linked to.
Chris
I can't think of many in-house systems that will do that sort of thing.
I'd strongly advise going for something a little more rugged than a hifi replacement driver. Think PA gear. There's much more efficiency on offer, and they're designed to be played loud for some time.
What SPL are you looking for?
You'll need something of high efficiency to go half-serious (120dB) with 80W.
I would expect that a single (or two) 18" drivers would easily out perform the 12" woofers you linked to.
Chris
What does what most folks have in the way of a sound system have to do with this thread?
For bass heavy music, it takes a very small room with lots of room gain (~ +18 dB IIRC) to get the kind of visceral 'entertainment' the OP wants at 30 Hz that ~115 dB/m can be at >100 Hz.
I agree that if only one driver is used that it needs to be a good quality ($$) prosound unit, but as efficiency rises with increasing number of drivers it becomes less critical when the amp's rated power is ~on a par with the driver's continuous rating, so it boils down to how many inexpensive drivers can be had within both the financial and size constraints.
Anyway, unless the OP has enough room gain to make up for his lack of available speaker space, then what driver(s) he uses is moot at least for now.
GM
For bass heavy music, it takes a very small room with lots of room gain (~ +18 dB IIRC) to get the kind of visceral 'entertainment' the OP wants at 30 Hz that ~115 dB/m can be at >100 Hz.
I agree that if only one driver is used that it needs to be a good quality ($$) prosound unit, but as efficiency rises with increasing number of drivers it becomes less critical when the amp's rated power is ~on a par with the driver's continuous rating, so it boils down to how many inexpensive drivers can be had within both the financial and size constraints.
Anyway, unless the OP has enough room gain to make up for his lack of available speaker space, then what driver(s) he uses is moot at least for now.
GM
The budget is small probobly total <120GBP (including MDF fixing etc), as it's more a recycling of midranges and tweeters from a project that I grew to dislike and is taking up space. I will do some mesurments using my esiting subs in the place I want to put it to see how much room gain I have. My current subs are only capable of about 102dB @ 30Hz so to me 120dB is very loud!
As for amps I am designing the crossover and eq circuits as just line level active filters and so it would be trivial to upgrade. Infact I have a 250W amp that I will hopefully fix after my exams under my bed. So if using 4x80W woofers I will have some headroom for upgrade.
As for amps I am designing the crossover and eq circuits as just line level active filters and so it would be trivial to upgrade. Infact I have a 250W amp that I will hopefully fix after my exams under my bed. So if using 4x80W woofers I will have some headroom for upgrade.
You need to describe all the gear you currently have and what you plan on reusing,what models etc.
In that case I would consider a front loaded horn with a 10" or so. This will give you about 104dB/1w/1m in approx 200litre minimum down to 45hz in a corner from memory. Quite often car audio subwoofers work fine in these.
If you could build two you could reach to perhaps 35hz if you get some nice boundary reinforcement.
A tapped horn is possible and are slightly harder to model, but can be easier to build with straight sections.
Since its dubstep etc I see no problem with sub that is 15dB more sensitive than the midrange,the budget dictates no horns for top end.
Midrange/tweeter doesnt matter quite as much since your budget is low, and reusing components.
In that case I would consider a front loaded horn with a 10" or so. This will give you about 104dB/1w/1m in approx 200litre minimum down to 45hz in a corner from memory. Quite often car audio subwoofers work fine in these.
If you could build two you could reach to perhaps 35hz if you get some nice boundary reinforcement.
A tapped horn is possible and are slightly harder to model, but can be easier to build with straight sections.
Since its dubstep etc I see no problem with sub that is 15dB more sensitive than the midrange,the budget dictates no horns for top end.
Midrange/tweeter doesnt matter quite as much since your budget is low, and reusing components.
I have allready got midrange drivers and tweeters, they are going to be passivly crossed over and are capable of aprox 120dB max output limited by the tweeter which is a ribbon, they will have a passive crossover. I plan on constructing my own air core inductors as enamaled wire is cheaper than finished inductors and I am a 2nd year EEE undergrad so I can easily work out the inductance of a coil without mesurment.
I also have an 80+80W amp this will power the sub with one channel and the midrange/trebble with the other one. As this system is mono, stereo imaging is imposible in its location. Crossover between the subs and midrange will be active via state variable filters. I will be able to upgrade the amplifier to a 250W unit at some point in the future, it's curently broken.
Problem with horn loading is that as far as I can tell it involved angled cuts when my sum total of tools is a saw and a jigsaw and a drill, only rearly works for square boxes and even then they look very ugly (although seal well)!
I can get hold of some prosound 15" woofers near me which so far seems the best option:
SkyTronic product: HEAVY DUTY PRO MUSIC WOOFERS WITH ALUMINIUM FRAME
although these are expensive enough that I can only afford one.
Is the recomendation pretty much I should be tuning for 40Hz not 30Hz? I'm more used to lower power HI-FI systems!
I also have an 80+80W amp this will power the sub with one channel and the midrange/trebble with the other one. As this system is mono, stereo imaging is imposible in its location. Crossover between the subs and midrange will be active via state variable filters. I will be able to upgrade the amplifier to a 250W unit at some point in the future, it's curently broken.
Problem with horn loading is that as far as I can tell it involved angled cuts when my sum total of tools is a saw and a jigsaw and a drill, only rearly works for square boxes and even then they look very ugly (although seal well)!
I can get hold of some prosound 15" woofers near me which so far seems the best option:
SkyTronic product: HEAVY DUTY PRO MUSIC WOOFERS WITH ALUMINIUM FRAME
although these are expensive enough that I can only afford one.
Is the recomendation pretty much I should be tuning for 40Hz not 30Hz? I'm more used to lower power HI-FI systems!
Your Search Results | CPC
Press show results, have a look through. That site is the best I've found for driver choice, and they deliver.
But yeah, 40Hz is much easier than 30Hz.
Press show results, have a look through. That site is the best I've found for driver choice, and they deliver.
But yeah, 40Hz is much easier than 30Hz.
If you can get an institution discount code you can use onecall which stocks farnell and cpc's stuff at much lower prices. This place is near me in london and stocks better drivers:
Cricklewood Electronics - CCTV. CCTV Equipment. CCTV Systems. Digital CCTV Cameras
quickly running the numbers I can get 110dB from one of these and have a small enough enclosure to add another at a latter date.
Cricklewood Electronics - CCTV. CCTV Equipment. CCTV Systems. Digital CCTV Cameras
quickly running the numbers I can get 110dB from one of these and have a small enough enclosure to add another at a latter date.
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The T/S parameters for the Skytronic stuff are wrong. The two 15s on the T/S pdf look very, very poor. Any expense or effort to build a box for these drivers would be a waste.
The £85.19 inc VAT for the Precision Devices 12 is a steal, I wish we could get this driver in the USA.
"Problem with horn loading is that as far as I can tell it involved angled cuts "
The design shown above is a Tapped Horn and does not have a bunch of angles. Most lumberyards have a panel saw and could make the long straight cuts for you.
The £85.19 inc VAT for the Precision Devices 12 is a steal, I wish we could get this driver in the USA.
"Problem with horn loading is that as far as I can tell it involved angled cuts "
The design shown above is a Tapped Horn and does not have a bunch of angles. Most lumberyards have a panel saw and could make the long straight cuts for you.
wow yes that pd driver is far better, I didn't know CPC had such a larger range than onecall I thought all stock was the same. As for skytronic drivers I think the problem is incorrect data entry as I think the cms should be 93.4um/N not 934 then the parameters don't contridict. I have some 10" skytronics and they behave as simulated. Anyway I will look more into easy to build tapped horns, thanks for the help.
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