I am looking to build an OB speaker which might use 8" (or even 10") woofer along with dayton's 3" ps95-08 fullrange driver. the idea is to mate this 2way with a subwoofer which would handle below 120hz. while 8/10" woofer would handle from 120hz to 700-800hz and the remaining by the full range driver.
1. what type of OB I can use here? U-frame, H-frame, just a plane baffle etc ?
2. the xo points chosen are ok?
3. getting the 8/10" in OB to cover down to 120hz is possible?
1. what type of OB I can use here? U-frame, H-frame, just a plane baffle etc ?
2. the xo points chosen are ok?
3. getting the 8/10" in OB to cover down to 120hz is possible?
Hi,
Yes its very doable. You want a high Fs and Qts PA type bass driver.
Read and digest : http://www.quarter-wave.com/OBs/OB_Design.pdf
For a 10" wide plain baffle double the x/o point. 120Hz is no problem.
rgds, sreten.
Yes its very doable. You want a high Fs and Qts PA type bass driver.
Read and digest : http://www.quarter-wave.com/OBs/OB_Design.pdf
For a 10" wide plain baffle double the x/o point. 120Hz is no problem.
rgds, sreten.
I made an U frame with a 10 " and a 4"
Rather unusual 'cos the Fc is same as usual 2-way speakers ( well...considering the natural operating bandwidth of the two, I'd say about 500 Hz 🙄😉
The 4" is an old Pioneer with a piezo tweeter - yes, a coaxial for car
The 10 " waveguide acts also like a horn 'cos the speaker is a little receeded ( for the suspensions not to touch the surface ....)
Rather unusual 'cos the Fc is same as usual 2-way speakers ( well...considering the natural operating bandwidth of the two, I'd say about 500 Hz 🙄😉
The 4" is an old Pioneer with a piezo tweeter - yes, a coaxial for car
The 10 " waveguide acts also like a horn 'cos the speaker is a little receeded ( for the suspensions not to touch the surface ....)
sreten,
double the xo point means double of 'fs' you mean?
in that case i need to chose a woofer which has fs of ~60hz. right?
will there be any eq required?
double the xo point means double of 'fs' you mean?
in that case i need to chose a woofer which has fs of ~60hz. right?
will there be any eq required?
Fs is the resonance of the speaker measured in free air
Fc is Frequency Cut
If the woofer is used above 100-150 Hz ( much difference between these limits ! ) it doesn't need a lot of equalization, I'd say none 'cos the real and big equalization needed for OB happens under that frequency limit, and the baffle around the woofer ( also count the "fins" in OBs, as the lows are omnidirectional) sets the integration with woofer's emission, so the EQ is done by the baffle.
So the EQ required is the one operated by the filter
3" pro driver SPL at 1 W and 1 m should be about 90 dB
No worry about finding an 8" or 10" to match the sensitivity
I would make just a box about ( for a 10" ) 12X12X 10 ( depth )
with no back of course, and some sound absorber on the sides
If you find high sensitivity drivers ( such as Pros are...) and you find it difficult to match with mid/tw sensitivity, try a BIG waveguide ( you can do it with old big rotten drivers, with a lot of primer and sanding on the front and some reinforcement with lots of paper mache work on the back )
Fc is Frequency Cut
If the woofer is used above 100-150 Hz ( much difference between these limits ! ) it doesn't need a lot of equalization, I'd say none 'cos the real and big equalization needed for OB happens under that frequency limit, and the baffle around the woofer ( also count the "fins" in OBs, as the lows are omnidirectional) sets the integration with woofer's emission, so the EQ is done by the baffle.
So the EQ required is the one operated by the filter
3" pro driver SPL at 1 W and 1 m should be about 90 dB
No worry about finding an 8" or 10" to match the sensitivity
I would make just a box about ( for a 10" ) 12X12X 10 ( depth )
with no back of course, and some sound absorber on the sides
If you find high sensitivity drivers ( such as Pros are...) and you find it difficult to match with mid/tw sensitivity, try a BIG waveguide ( you can do it with old big rotten drivers, with a lot of primer and sanding on the front and some reinforcement with lots of paper mache work on the back )
assuming 8/10" woofer and dayton ps95(which i have decided to use in this setup),
what would be the possible xo between these two?
say if i select between 500hz to 800hz then what would be the baffle width requirements for dayton ps95? this driver is just 3". i am willing to increase xo for this to 1khz if necessary.
what would be the possible xo between these two?
say if i select between 500hz to 800hz then what would be the baffle width requirements for dayton ps95? this driver is just 3". i am willing to increase xo for this to 1khz if necessary.
For the mid range region an 8-10" diameter mid-woofer would be fine. You can select your mid-woofer to have a sensitivity that best matches with the subwoofer and tweeter array sound levels if you are thinking of a passive crossover between each band in your final speaker design. An all active crossover would give you more latitude for driver selection.
Do not use an H-frame or U-frame enclosure for the mid-woofer but instead a flat baffle for this driver. Neither a H-frame or U-frame mounting will permit you to cover your desired mid range frequencies without resonance peaks or dips in your desired frequency range. You can use various models to calculate your baffle width but I'm more old school on this subject. The mid-woofer baffle width will be determined primarily by your subwoofer to mid-woofer crossover frequency while the mid-woofer/tweeter array crossover frequency will be the determining factor for your tweeter-array baffle width.
My best recommendation is to build a test baffle and measure or listen to determine whether you have adequate mid-range and tweeter performance. You can even use foam board or similar material to permit trimming to suit your needs if you need to experiment. Thus you can optimize your baffle widths to ascertain the best baffle size for the final speaker. Of course if you have the ability to equalize the entire frequency response then you have more liberty to correct the final speaker to your needs.
Do not use an H-frame or U-frame enclosure for the mid-woofer but instead a flat baffle for this driver. Neither a H-frame or U-frame mounting will permit you to cover your desired mid range frequencies without resonance peaks or dips in your desired frequency range. You can use various models to calculate your baffle width but I'm more old school on this subject. The mid-woofer baffle width will be determined primarily by your subwoofer to mid-woofer crossover frequency while the mid-woofer/tweeter array crossover frequency will be the determining factor for your tweeter-array baffle width.
My best recommendation is to build a test baffle and measure or listen to determine whether you have adequate mid-range and tweeter performance. You can even use foam board or similar material to permit trimming to suit your needs if you need to experiment. Thus you can optimize your baffle widths to ascertain the best baffle size for the final speaker. Of course if you have the ability to equalize the entire frequency response then you have more liberty to correct the final speaker to your needs.
thanks Jim.
probably i will go with all active solution, just to have more control over filtering and EQing.
sub to woofer/mid freq cutoff i am planning at 120hz.
mid-tweeter freq cutoff is what i have to decide. i am thinking of somewhere between 500-800hz. since ps95 a low power driver(just 10w rms) i guess crossing higher will result in more efficiency. as you suggested i will experiment with diff baffle sizes.
however i wonder if there is any formula for calculating the cutoff freq given the baffle width or vice versa!
probably i will go with all active solution, just to have more control over filtering and EQing.
sub to woofer/mid freq cutoff i am planning at 120hz.
mid-tweeter freq cutoff is what i have to decide. i am thinking of somewhere between 500-800hz. since ps95 a low power driver(just 10w rms) i guess crossing higher will result in more efficiency. as you suggested i will experiment with diff baffle sizes.
however i wonder if there is any formula for calculating the cutoff freq given the baffle width or vice versa!
You need to determine both the baffle width for the mid-woofer and the baffle width for the tweeter array. The width of the baffle around the mid-woofer is driven primarily by the low end crossover frequency while the tweeter array likely would need a baffle width no wider than the tweeter frame size.
I have a recent 3-way open back design that consists of a 15" diameter woofer (Eminence Kapalite 3015LF Neo) mounted in a u-frame, a 10" diameter midrange (Faital 10PR300), and a Hawthorne Audio 700 AMT tweeter. The tweeter front waveguide is 7" wide by 8" high for scale. The active crossover frequencies were at 175 Hz and 700 Hz. Note the sloped sides of the baffle that minimizes the overall width for the mid-woofer and tweeter portion of the baffle. I constructed a MDF test baffle to verify performance for the mid woofer and tweeter mounting before cutting the wood baffle.
The photo sizing is such that the speaker looks much wider that it is. Click on the photo to re-size and correct its width. The overall baffle is 18" wide by 42" tall. The baffle width at the center of the mid-woofer is 14" and 10.5" for the tweeter center line.
Jim
I have a recent 3-way open back design that consists of a 15" diameter woofer (Eminence Kapalite 3015LF Neo) mounted in a u-frame, a 10" diameter midrange (Faital 10PR300), and a Hawthorne Audio 700 AMT tweeter. The tweeter front waveguide is 7" wide by 8" high for scale. The active crossover frequencies were at 175 Hz and 700 Hz. Note the sloped sides of the baffle that minimizes the overall width for the mid-woofer and tweeter portion of the baffle. I constructed a MDF test baffle to verify performance for the mid woofer and tweeter mounting before cutting the wood baffle.
The photo sizing is such that the speaker looks much wider that it is. Click on the photo to re-size and correct its width. The overall baffle is 18" wide by 42" tall. The baffle width at the center of the mid-woofer is 14" and 10.5" for the tweeter center line.
Jim
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😱 passive are scary for sure.
but also true is that i am at experimental stage. my setup is indeed the simplest one (not the best maybe) consisting of a 5.1 sound card. i get to play with xo points, EQing, level adjustments and phase adjustments which passive solution cant offer!
Jim,
your driver selection is interesting. the midwoofer (faital 10pr300) has low Qts of 0.27 which is contrary to popular belief that OB drivers should have high Qts....or at xover of 175hz the Qts values doesn't matter much?
for midwoofer job I am also looking for pro driver. One option is fane 8-225 8". unfortunately 8-125 is unavailable which has high Qts.
Fane International Ltd Loud Speakers
your driver selection is interesting. the midwoofer (faital 10pr300) has low Qts of 0.27 which is contrary to popular belief that OB drivers should have high Qts....or at xover of 175hz the Qts values doesn't matter much?
for midwoofer job I am also looking for pro driver. One option is fane 8-225 8". unfortunately 8-125 is unavailable which has high Qts.
Fane International Ltd Loud Speakers
I using an active system with a DEQX processor for crossover and full frequency range EQ capabilities. Thus I'm not too limited by passive crossover Qts thinking in this design.
I liked the FaitalPRO driver because of its higher SPL capability at my crossover frequency vs. mid-woofers from other companies.
e
I liked the FaitalPRO driver because of its higher SPL capability at my crossover frequency vs. mid-woofers from other companies.
e
i came across this interesting thread
http://www.diyaudio.com/forums/full...parison-3in-4in-class-full-range-drivers.html
here ps95 is mounted on a trapezoidal baffle and in a sealed spiral shaped box designed to absorb the rear wave completely(?). in one of the graph the author shows comparison of spiral box and large flat OB and essentially they both have same freq response.
http://www.diyaudio.com/forums/full...parison-3in-4in-class-full-range-drivers.html
here ps95 is mounted on a trapezoidal baffle and in a sealed spiral shaped box designed to absorb the rear wave completely(?). in one of the graph the author shows comparison of spiral box and large flat OB and essentially they both have same freq response.
Yes, that is my thread. If you want to listen to what a PS95-8 sounds like in that speaker with a low XO to a woofer at 225Hz, look in the Subjective Blind comparison thread.
http://www.diyaudio.com/forums/full...nd-comparison-3in-5in-full-range-drivers.html
The Ps95 works great paired with a woofer like the RS225. I have a speaker that uses a "Dagger" rear chamber for no coloration. More info here:
http://www.diyaudio.com/forums/full-range/273524-10f-8424-rs225-8-fast-ref-monitor.html
tried simulating ps95 and fane 8-225 using xlbaffle.xls
dont know how to simulate the xover points in this. wonder if any similar tool exists for OB and xover sim!
dont know how to simulate the xover points in this. wonder if any similar tool exists for OB and xover sim!
Yes, you can simulate both XO and OB drivers with Akabak.
For example here is an OB using 3.5in Vifa TC9FD with a 6 driver SLOB woofer array:
More info here:
http://www.diyaudio.com/forums/full-range/249984-cheap-fast-ob-literally-2.html#post3795064
For example here is an OB using 3.5in Vifa TC9FD with a 6 driver SLOB woofer array:
More info here:
http://www.diyaudio.com/forums/full-range/249984-cheap-fast-ob-literally-2.html#post3795064
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thanks xrk. i went through your 'subjective' and 'objective' threads. great lot of information available in them. your measurements for ps95 have just given me more confidence in them now (given not many projects exist using this little driver). surely will try out akabak.
PS95-8 is surely an under-rated and under-used driver. Quite a little budget gem. I am listening to them now and really like them. Make sure you mount it flush with rebate for bezel. That will reduce a 3dB ripple in response.
Hi,
http://www.quarter-wave.com/OBs/OB_Design.pdf
No, I meant double the x/o points used in the 20" wide baffle for 10" wide.
As in the article you want a bass mid about 6dB louder than the FR.
Bass Fs and Qts are not so critical with a 120Hz active x/o.
rgds, sreten.
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