A friend gave me a free subwoofer box. Typical dual 12" sealed, cheap car box with really, really, really low grade MDF. Had some crap old home woofer, and a JL 12W3 D4 (second generation with dual 4 ohm coils).
Woofer tested good, but surround was gone. I was not in mood to re-foam it myself, so had someone do it. Cost more than I had originally wanted, but a similar quality woofer would have cost just as much with shipping, or more (There's a local place that does great re-cone and re-foam work, have used them before). I am talking about a different brand, not JL. A new 12w3 is over 200 bucks. No thanks! I like the look of the old ones, too. I am sure a cheap dayton from PE is comparable in price and quality.
Sounds incredible due to proper seal, stuffing, bracing, and looks better than most of my boxes. Just don't look at it in the sunlight.
It's for only music and is part of a continually growing and expanding "multiple sub approach". I moved one of the smaller subs to my "mini studio" for work duty. So still only 2 12" subs in my main system... Getting there slowly, but surely...
Woofer tested good, but surround was gone. I was not in mood to re-foam it myself, so had someone do it. Cost more than I had originally wanted, but a similar quality woofer would have cost just as much with shipping, or more (There's a local place that does great re-cone and re-foam work, have used them before). I am talking about a different brand, not JL. A new 12w3 is over 200 bucks. No thanks! I like the look of the old ones, too. I am sure a cheap dayton from PE is comparable in price and quality.
Sounds incredible due to proper seal, stuffing, bracing, and looks better than most of my boxes. Just don't look at it in the sunlight.
It's for only music and is part of a continually growing and expanding "multiple sub approach". I moved one of the smaller subs to my "mini studio" for work duty. So still only 2 12" subs in my main system... Getting there slowly, but surely...
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That doesn't look like a dual 12" car audio box.
I agree concerning the look of the old JLs btw. Usually decent specs too. The foam surround is an issue, but it's easily repairable.
POC2 has been replaced by POC3, which uses the same PA310 driver but in a TH with a different fold. The fold follows the "SS15" type of fold which results in the shortest panels being at S1, which reduces the possibility of panel flex which in turn reduces distortion. POC3 also has quite a bit more bracing than what was used in POC2 to ensure that panel flex was minimized as much as possible. With POC2, anything that was placed on top of the cabinet (including one of my Blastoramas) was in danger of being vibrated off at higher volumes. This does not happen with the POC3. I also aimed for a slightly higher efficiency and slightly higher cutoff point with the POC3 design, but the main aim was to come up with a box with more suitable dimensions for transportation in my car.
As with the POC2, output of course is limited by the driver's relatively low Xmax (5mm). For greater output an Eminence Kappalite 12" could probably be used instead, with only minor changes in frequency response, but significantly greater peak output levels.
Pics and link below:
The Subwoofer DIY Page v1.1 - Projects : "Proof of Concept #3"
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Good observation.
I had written a very long post, and edited it down. The part describing me cutting the box down due to water damage was left out. I wanted to use the whole cabinet (2.6 ft3) with 2 tens in a "push pull slot loaded bass reflex" configuration. But the damage was too great. After taking the carpet off, I realized it would be easiest and more cost effective to cut it down and use the single woofer. I just took it apart (stapled, not glued) and cut down the baffle and cut the other panels to match. The center divider was moved over to give me a little more volume so I could get a tiny bit more depth and also make up for braces. The original cuts were all accurate and sealed/glued perfect!
I might look into building a TH for this woofer in the future. But not sure what parameters make a good TH. I have 3 pairs of different subs to try, and this single JL. I need to get off my butt and learn hornresp or whatever... Just am not motivated to learn because I don't have money to spend on wood right now.
Seeing your TH, Brian, motivates me to make some (or 1)...
Not bad in fact. It's more sensitive than my two Alpine Type-R 12D2 drivers (combined 2 Ohm load), but could not beat them at raw SPL at very low frequencies of course.
Now if I had something like the Eminence Kappalite 12" in the TH instead, the SPL results would have been a LOT closer
Played around with one of my SI HT18s today - 5/6ths of a box (one side missing), sitting with the open side down...what a treat! It pretty much destroyed my dual 12" ported subs with no fuss.
End state is going to be dual 18s in ~8.8cuft ported to ~10Hz with EQ. Looking at around 114dB full tilt...minus a few for power compression and port losses. Peak air velocity of around 37m/s@10Hz@108dB. -3dB is at 13Hz, -1dB at 30Hz - so a nice little downward tilt. -6dB@10.5Hz.
End state is going to be dual 18s in ~8.8cuft ported to ~10Hz with EQ. Looking at around 114dB full tilt...minus a few for power compression and port losses. Peak air velocity of around 37m/s@10Hz@108dB. -3dB is at 13Hz, -1dB at 30Hz - so a nice little downward tilt. -6dB@10.5Hz.
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NicePlayed around with one of my SI HT18s today - 5/6ths of a box (one side missing), sitting with the open side down...what a treat! It pretty much destroyed my dual 12" ported subs with no fuss.
End state is going to be dual 18s in ~8.8cuft ported to ~10Hz with EQ. Looking at around 114dB full tilt...minus a few for power compression and port losses. Peak air velocity of around 37m/s@10Hz@108dB. -3dB is at 13Hz, -1dB at 30Hz - so a nice little downward tilt. -6dB@10.5Hz.
~4.4cuft per driver seems small for a ported box for the SI HT18s? Mine are around 3.75cuft each and they're sealed!
(EDIT: Or are you referring to 8.8cuft per driver? In which case ignore my ramblings
lol)Oh, and I have to ask - what are the giant white speakers?!
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No, you were right - 4.4cubes per driver. The beauty of Linkwitz Transform
White speakers are my Open Baffles
http://www.diyaudio.com/forums/multi-way/123512-ultimate-ob-gallery-141.html#post4138742
http://www.diyaudio.com/forums/multi-way/123512-ultimate-ob-gallery-143.html#post4144255
White speakers are my Open Baffles
http://www.diyaudio.com/forums/multi-way/123512-ultimate-ob-gallery-141.html#post4138742
http://www.diyaudio.com/forums/multi-way/123512-ultimate-ob-gallery-143.html#post4144255
I've performed a few performance measurements over the last few days which might be of interest for those considering TH builds.
The first one is the response of the POC3 under various power levels, with DSP used to flatten its response through the passband and up to 200 Hz, and steep filters on either end of this passband. HornResp suggests that the POC3's driver would start exceeding Xmax within its passband under 100W, but I was able to put over double that into it without major distortion (see red line in the graph). Power compression (10 second sine sweep) is 1dB or less, centered around the POC3's Fb. This is one of the main advantages of this type of build, compared to vented boxes. There is little or no audible change in tone at low frequencies as volume goes up, compared to vented boxes where port compression can be significant if the vents are small.
The second show's the POC3's response combined with one of my Blastoramas, measured at 25 feet. This time no DSP is being used on the POC3, but there's a 48dB/oct BW HP filter at 30 Hz to eliminate excursion issues below Fb, and the xover to the Blastorama is 100 Hz LR 24dB/octave. There was a bit of breeze, so I won't trust anything below 40 Hz or so. Of course the breeze died down as soon as I packed everything up, grrr....
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I like this forum because everybody shows what they have but don't try to say that they're better than others... you just want to help and give all what you know to others... that's really cool... didn't find this on every forum
tomorrow I'm gonna post my version of THAM12, didn't make it exactly the same... because my driver perform better with these little changes
tomorrow I'm gonna post my version of THAM12, didn't make it exactly the same... because my driver perform better with these little changes
My first Sub
Heres mine!
Still needs some work but I'm pretty happy so far
First DIY Subwoofer - Album on Imgur
Heres mine!
Still needs some work but I'm pretty happy so far
First DIY Subwoofer - Album on Imgur
speaker mounting
hi brian
we almost had the same idea of speaker mounting,i used 27mm plyboard,then
like you did,,"and cut so that the driver is countersunk into the hole. Doing it this way ensures that the driver is properly positioned over the cutout, as any minor leaks in this area will result in a considerable loss in low-frequency output.",,,,,,,,,,,,,,,,,,,,,,,,,,
and as the back of driver was flush with the board i made a ring from plywood and used 10mm bolts to secure the speaker,,,,
greeeetz
hi brian
we almost had the same idea of speaker mounting,i used 27mm plyboard,then
like you did,,"and cut so that the driver is countersunk into the hole. Doing it this way ensures that the driver is properly positioned over the cutout, as any minor leaks in this area will result in a considerable loss in low-frequency output.",,,,,,,,,,,,,,,,,,,,,,,,,,
and as the back of driver was flush with the board i made a ring from plywood and used 10mm bolts to secure the speaker,,,,
greeeetz
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