Newbie alert.. I know next to nothing about speaker parameters but i will try my best spill what i know just so you know how best to tackle my conundrum.
I want to build a simple sound system for a small coffee shop i'm about to open. This speaker system will be placed close to a wall in front of which will be people moving so it can't be a "deep" cabinet system, i.e should be a thin as possible without obstructing the way. There will be an LCD TV installed to the wall so the best case scenario would be to have a speaker system which is just about the thickness of said LCD TV. I can build any amp to match the driver but for now i have a simple single ended tube amp with approx 3W of output. I also have a small Class D module, good for 10W.
I'm thinking of a simple open baffle system made of a pair of 2240 x 1220mm (8 x 4 feet) plywood, one for each driver. Perhaps 18mm thickness?
This is the driver i'm planning of using a local made PA driver which is ACR 1230 NEW: 12″ C-1230 PA ACR SPECIAL NEW | ACR Speaker
Here are the specs in English:
Specs:
Speaker diam.= 12 inch
Impedance = 8 ohm
Max power = 500W
Freq Bandwidth = 45Hz - 17.6kHz
SPL (2.83 V / 1 m) = 94dB
Effective Cone diam. = 273mm
Magnetic Field? = 1.01Tesla , not sure if i translated this correctly
Magnet weight = 0.8 kg / 27.93 Oz
Voice coil diameter = 49.5mm
Voice coil material = kapton
TS Parameter
Fs = 45Hz
DCR = 7.2ohm
Qts = 0.93 (AFAIK Qts > 0.7 is good for open baffle?)
Qes = 1.03
Qms = 9.78
Mms = 42.3g
Cms = 0.31mm/N
BL Product = 9.2Tm
Vas = 110.3L
No = 0.89%
Sd = 506.7cm2
Xmax = 6.9mm
There is also a pdf spec sheet here http://acrspeaker.com/wp-content/uploads/2015/05/3MN0197-00-MN-C-1230-PA-ACR-SPECIAL-NEW-REV-4.pdf containing the attached impedance and freq response curve
1. Is this a good driver for my plan? My plan is to attach the baffle as close as possible to the wall to keep it as thin as possible.
2. Can i just simply use a pair of said plywood and make the holes for the driver.. can i make it even smaller, i.e one sheet of plywood split in two, so each baffle will be approx 4 x 4 feet? I also read the driver can't be put symmetrical to the baffle, i.e it should be a bit offset with respect to the baffle edges.
3. Will i need to add tweeter? Knowing nothing about crossover design, can i just use one cap for the high pass filter?
4. Any other input/suggestion or even a link on how to design this will be appreciated
I want to build a simple sound system for a small coffee shop i'm about to open. This speaker system will be placed close to a wall in front of which will be people moving so it can't be a "deep" cabinet system, i.e should be a thin as possible without obstructing the way. There will be an LCD TV installed to the wall so the best case scenario would be to have a speaker system which is just about the thickness of said LCD TV. I can build any amp to match the driver but for now i have a simple single ended tube amp with approx 3W of output. I also have a small Class D module, good for 10W.
I'm thinking of a simple open baffle system made of a pair of 2240 x 1220mm (8 x 4 feet) plywood, one for each driver. Perhaps 18mm thickness?
This is the driver i'm planning of using a local made PA driver which is ACR 1230 NEW: 12″ C-1230 PA ACR SPECIAL NEW | ACR Speaker
Here are the specs in English:
Specs:
Speaker diam.= 12 inch
Impedance = 8 ohm
Max power = 500W
Freq Bandwidth = 45Hz - 17.6kHz
SPL (2.83 V / 1 m) = 94dB
Effective Cone diam. = 273mm
Magnetic Field? = 1.01Tesla , not sure if i translated this correctly
Magnet weight = 0.8 kg / 27.93 Oz
Voice coil diameter = 49.5mm
Voice coil material = kapton
TS Parameter
Fs = 45Hz
DCR = 7.2ohm
Qts = 0.93 (AFAIK Qts > 0.7 is good for open baffle?)
Qes = 1.03
Qms = 9.78
Mms = 42.3g
Cms = 0.31mm/N
BL Product = 9.2Tm
Vas = 110.3L
No = 0.89%
Sd = 506.7cm2
Xmax = 6.9mm
There is also a pdf spec sheet here http://acrspeaker.com/wp-content/uploads/2015/05/3MN0197-00-MN-C-1230-PA-ACR-SPECIAL-NEW-REV-4.pdf containing the attached impedance and freq response curve
1. Is this a good driver for my plan? My plan is to attach the baffle as close as possible to the wall to keep it as thin as possible.
2. Can i just simply use a pair of said plywood and make the holes for the driver.. can i make it even smaller, i.e one sheet of plywood split in two, so each baffle will be approx 4 x 4 feet? I also read the driver can't be put symmetrical to the baffle, i.e it should be a bit offset with respect to the baffle edges.
3. Will i need to add tweeter? Knowing nothing about crossover design, can i just use one cap for the high pass filter?
4. Any other input/suggestion or even a link on how to design this will be appreciated
Attachments
I personally suggest a cornu spiral enclosure. I built one with foam core and it was pretty impressive. Done with a good full range driver I think it would suit your needs Might I add that open baffle against a wall isn't the best idea unless you're just looking for any kind of sound irregardless of quality. You need space behind an open baffle speaker.
http://www.diyaudio.com/forums/full...k-building-cornu-spiral-horn-now-you-can.html
Wes
http://www.diyaudio.com/forums/full...k-building-cornu-spiral-horn-now-you-can.html
Wes
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That conu doesn't look something a first time builder like me would build. Besides, i am looking for a cheap build and the drivers for that conu isn't cheap. The ACR 1230 is only like usd13-15 per pc.
Can the loss of low end from having the driver at such close distance to the wall be compensated by increasing the amp's output impedance? That is to bump the power around Fs bu reducing damping factor.
I made the cornu with very very cheap foam board and a recycled midrange driver(4 inch) and I am a novice builder at best. Many have used drivers in the $10-20 USD range with good results. Good bass response and no BSC. I was floored by the result considering the time and money put into it.
If you're stuck on the idea of using that driver and OB I suppose you could give it a try. Maybe use a subwoofer or DSP to tweak it but I feel like you're trying to jam a square peg in a round hole going this route. Maybe one of the more knowledgeable members will chime in with some ideas. Good luck.
Wes
If you're stuck on the idea of using that driver and OB I suppose you could give it a try. Maybe use a subwoofer or DSP to tweak it but I feel like you're trying to jam a square peg in a round hole going this route. Maybe one of the more knowledgeable members will chime in with some ideas. Good luck.
Wes
"open baffle" and "as close as possible to the wall" don't go together. Open baffle need to be at least 1 m (or yard) distance from the (parallel) wall.
Build simple closed box 3x3 feet and of the same depth as the depth of the driver.
Large sealed box would get my vote. Put a lot of stuffing in there, too, or reflections will be a problem.
Chris
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