I wanted to try an Isobaric with a removable cylindrical container and made a "one piece motor" by gluing 3/4" x 3/4" rings together. The setup was way better than previous attempts.
1. cut the inter circle first
2. use the waste/cutout to center the piece to the sliding table (2nd pic top).
3. glue together with spring clamps, etc.
Box size, 1 cubic foot with deductions for venting and cylindrical container calculated in.
The woofer is a Buyout from PE, very low cost but well made.
Simulated in WinIsd, clearly shows a response down to 25hz.
299-114 subwoofer speaker features a deep profile, long fiber, high-pulp cone finished beautifully in a protective coating that also dampens resonances. The 1-1/2" diameter 4-layer voice coil's 5/8" winding length maintains plenty of copper in the magnetic gap, ensuring plenty of high-impact, low-distortion output. A vented pole piece reduces performance-robbing power compression, and the magnet structure's extended back plate prevents "bottoming out" the long voice coil. Great subwoofer speaker for any design or application, particularly multimedia systems, small home theater setups, and multi-driver configurations.
Specifications:
*Power handling: 80 watts RMS/160 watts max
*VCdia: 1-1/2"
*Le: 1.61 mH
*Impedance: 4 ohms
*Re: 3.25 ohms
*Frequency response: 35-2,000 Hz
*Fs: 38 Hz *SPL: 83.5 dB 1W/1m
*Vas: 0.55 cu. ft. *Qms: 6.74
*Qes: 0.64 *Qts: 0.59
*Xmax: 4.5 mm
*OD: 6-1/2"
A few more finish steps to go, will be testing soon though.
1. cut the inter circle first
2. use the waste/cutout to center the piece to the sliding table (2nd pic top).
3. glue together with spring clamps, etc.
Box size, 1 cubic foot with deductions for venting and cylindrical container calculated in.
The woofer is a Buyout from PE, very low cost but well made.
Simulated in WinIsd, clearly shows a response down to 25hz.
299-114 subwoofer speaker features a deep profile, long fiber, high-pulp cone finished beautifully in a protective coating that also dampens resonances. The 1-1/2" diameter 4-layer voice coil's 5/8" winding length maintains plenty of copper in the magnetic gap, ensuring plenty of high-impact, low-distortion output. A vented pole piece reduces performance-robbing power compression, and the magnet structure's extended back plate prevents "bottoming out" the long voice coil. Great subwoofer speaker for any design or application, particularly multimedia systems, small home theater setups, and multi-driver configurations.
Specifications:
*Power handling: 80 watts RMS/160 watts max
*VCdia: 1-1/2"
*Le: 1.61 mH
*Impedance: 4 ohms
*Re: 3.25 ohms
*Frequency response: 35-2,000 Hz
*Fs: 38 Hz *SPL: 83.5 dB 1W/1m
*Vas: 0.55 cu. ft. *Qms: 6.74
*Qes: 0.64 *Qts: 0.59
*Xmax: 4.5 mm
*OD: 6-1/2"
A few more finish steps to go, will be testing soon though.
Attachments
Nicely done!
Have you considered isobaric with just two woofers mounted on the same baffle each from opposite side in clam arrangement? Not only it is much simpler, but it reduces distortion.
Furthermore, you hear the sound radiating from the back of woofer, which reduces higher frequencies, making crossover easier.
I am very fond of isobaric.
Have you considered isobaric with just two woofers mounted on the same baffle each from opposite side in clam arrangement? Not only it is much simpler, but it reduces distortion.
Furthermore, you hear the sound radiating from the back of woofer, which reduces higher frequencies, making crossover easier.
I am very fond of isobaric.
Shape of the simulated response is poor (bad sound quality) because tuning frequency is too low. Try with other box volume also.
Thanks Adason, will try that configuration, and back to back magnet (with different diy cylinders).
Sonce, so don't know, so far the lightweight box is digging down really low and exceeded all my expectations. When WinIsd defaulted to 25hz I didn't even consider making it smaller, what are you recommending? .75 cubic foot?
In any case, I'm starting to believe....to get a good subwoofer sound, buy a dedicated subwoofer amp, with high end filter e.g. Dayon SA 230 or SA 1000.
Sonce, so don't know, so far the lightweight box is digging down really low and exceeded all my expectations. When WinIsd defaulted to 25hz I didn't even consider making it smaller, what are you recommending? .75 cubic foot?
In any case, I'm starting to believe....to get a good subwoofer sound, buy a dedicated subwoofer amp, with high end filter e.g. Dayon SA 230 or SA 1000.
Thanks! I did sim .6 and the response looked odd on my screen, I'll reload the parameters and try again.
If .6 is feasible - but not a workable because of super long port length, could add a second drive unit. (total 4 drivers)
However, here's a room response with mic in middle of room using the 1cf box. I reset the processor to factory default, so there shouldn't be any eq. The box is located in corner of room, on 8" stand.
Sure enough, 25hz!! but again a 40hz dip; something about the room I guess
[same results as other projects]
btw, the port is 10"wide x 1/2" x 18-3/4" It was supposed to be 18" long but forgot about the deduct for the 3/4" baffle.
If .6 is feasible - but not a workable because of super long port length, could add a second drive unit. (total 4 drivers)
However, here's a room response with mic in middle of room using the 1cf box. I reset the processor to factory default, so there shouldn't be any eq. The box is located in corner of room, on 8" stand.
Sure enough, 25hz!! but again a 40hz dip; something about the room I guess
[same results as other projects]
btw, the port is 10"wide x 1/2" x 18-3/4" It was supposed to be 18" long but forgot about the deduct for the 3/4" baffle.
Attachments
Last edited:
Yes, 40 Hz dip is room related, put microphone in your listening position and move the subwoofer around the walls.
cauz I bought a big box of them :-/
This was really an experiment to see if one pair would measure ok and then double or triple that size.
And very surprised that one Iso pair can handle normal listen levels without speaker pops, and/or damage.
Some other answers to previous page:
Connections wired 4 & 4 for an 8ohm load.
The 4mm xmax...they seem to have more than that, the back of the magnet is bumped out.
Pretty much a success although:
Are they tunned to low?
[25hz now]
Poor group delay, maybe someone can chime in on that a bit more.
Also any thought what was the original intent? What were these design for?
I'm sure it was a plan at one time for a small, low cost sub box, bandpass perhaps?
edit
Ok ran a quick sim and could cut the existing box down to .8cf and keep the same 18" port, tuning would rise to 29hz.
This was really an experiment to see if one pair would measure ok and then double or triple that size.
And very surprised that one Iso pair can handle normal listen levels without speaker pops, and/or damage.
Some other answers to previous page:
Connections wired 4 & 4 for an 8ohm load.
The 4mm xmax...they seem to have more than that, the back of the magnet is bumped out.
Pretty much a success although:
Are they tunned to low?
[25hz now]
Poor group delay, maybe someone can chime in on that a bit more.
Also any thought what was the original intent? What were these design for?
I'm sure it was a plan at one time for a small, low cost sub box, bandpass perhaps?
edit
Ok ran a quick sim and could cut the existing box down to .8cf and keep the same 18" port, tuning would rise to 29hz.
Last edited:
Hi there O: Lower group delay is sensitive to the location of the big peak on the HR group delay curve. I have found, lowering the frequency of the peak by adjusting input parameters will push the knee at the bottom of the group delay curve to the left (lower hz), where you may be able to attain 10ms group delay for the lowest desired frequency. However, doing this tends to cause a decrease in low corner of the frequency curve, which I find not desirable. I have found that 17 to 18 hz tuning produces this effect in simm's ...regards, Michael
Thank you Michael D.
Ron E. I know what will will happen if I use two in a box; it won't be long before I'll end up bolting 2 more woofers on top of them. Which I can remember doing with 8's, 10's and 12's.
What about 3 iso's in a 60l cabinet tuned to 29hz, the modeling is similar but slightly better.
Could wire up 3 series then parallel and end up with 6 ohm to the amp.
Doug
Ron E. I know what will will happen if I use two in a box; it won't be long before I'll end up bolting 2 more woofers on top of them. Which I can remember doing with 8's, 10's and 12's.
What about 3 iso's in a 60l cabinet tuned to 29hz, the modeling is similar but slightly better.
Could wire up 3 series then parallel and end up with 6 ohm to the amp.
Doug
Last edited:
Another Version:
The port is slightly shorter and vent is 9/16" vs. 1/2" (first mdf speaker)
Wood - light weight maple ply with U brace at the woofer(s) center.
Red line is the response with mic in center of room - no eq except the high pass filter.
It's a little clearer sounding, and woks well with the new placement/location.
The port is slightly shorter and vent is 9/16" vs. 1/2" (first mdf speaker)
Wood - light weight maple ply with U brace at the woofer(s) center.
Red line is the response with mic in center of room - no eq except the high pass filter.
It's a little clearer sounding, and woks well with the new placement/location.
Attachments
Thanks Rory, haven't had time to to model it, but the devil's hands have been busy the last few days.
Made a second light weight plywood box, and and added it to the front three.
L (sub) C (sub) R
At first two subs didn't work as well as I thought it would, but was able to move the high pass filter lower a bit and sounds more like what I had in mind.
I'll check out the recommendation soon.
Pic: Four (4) 3/4" spacer rings and 3/4" front baffle. Rabbit cut(s) 3/8" front and back, which ends up back at 3" I.D. Add a extra 1/8" for the gaskets (cork, ordered from ebay)
Thanks!
Made a second light weight plywood box, and and added it to the front three.
L (sub) C (sub) R
At first two subs didn't work as well as I thought it would, but was able to move the high pass filter lower a bit and sounds more like what I had in mind.
I'll check out the recommendation soon.
Pic: Four (4) 3/4" spacer rings and 3/4" front baffle. Rabbit cut(s) 3/8" front and back, which ends up back at 3" I.D. Add a extra 1/8" for the gaskets (cork, ordered from ebay)
Thanks!
Attachments
The twin pair of ply boxes (above) works nicely, although stacked them together vs. 12' apart. There was some kind of cancellation when they in different locations.
I still have 6 speakers not being used, thinking about a 2.5 - 3.0 cubic foot cube or similar sized tower.
[2 speakers each circle]
The question is what would be better, a "Y" or a Vertical Straight Line configuration?
Any thoughts?
Thanks!
I still have 6 speakers not being used, thinking about a 2.5 - 3.0 cubic foot cube or similar sized tower.
[2 speakers each circle]
The question is what would be better, a "Y" or a Vertical Straight Line configuration?
Any thoughts?
Thanks!
Attachments
Went with the speaker wheel. Made a 4 layer wood, 3 hole yoke, same ploy as before.
The 20" x 24" baffle is face down, all I need is a 5 sided 2.75 cubic foot box and some gaskets.
Thinking a removable front would be the best bet, could always cover it with formica to gussy it up (someday).
I really like the two iso boxes (stacked) that I'm using now, really nice solid bass, hopefully this will top them.
The 20" x 24" baffle is face down, all I need is a 5 sided 2.75 cubic foot box and some gaskets.
Thinking a removable front would be the best bet, could always cover it with formica to gussy it up (someday).
I really like the two iso boxes (stacked) that I'm using now, really nice solid bass, hopefully this will top them.
Attachments
Last edited:
Inktoresting design.
Not that impressed with the driver tho, sorry
Better driver Peerless by Tymphany SDS-160F25PR01-08 6-1/2" Paper Cone Woofer Speaker
Higher spl, greater Xmax, lower mass, and cheaper too boot.
This is what I use in my MLTL (hate that nomenclature)
Be careful with ISO, the inner driver will hit Xmax before the outer driver. If pushed hard will hit Xmech doing damage before you realize it, well, that is if the extreme distortion level doesn't get your attention first.
edit
This driver use to be listed as a subwoofer on Tymphany's website. I never understood why as it is nothing more than a decent midbass IMO.
Not that impressed with the driver tho, sorry
Better driver Peerless by Tymphany SDS-160F25PR01-08 6-1/2" Paper Cone Woofer Speaker
Higher spl, greater Xmax, lower mass, and cheaper too boot.
This is what I use in my MLTL (hate that nomenclature)
Be careful with ISO, the inner driver will hit Xmax before the outer driver. If pushed hard will hit Xmech doing damage before you realize it, well, that is if the extreme distortion level doesn't get your attention first.
edit
This driver use to be listed as a subwoofer on Tymphany's website. I never understood why as it is nothing more than a decent midbass IMO.
Last edited: