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And btw, this sub has both great output and efficiency. Compared to my DLS Iridium 12i in a relatively small sealed enclosure I had to decrease overall levels by 10-15dB. They did not lie about the 25mm p-p excursion, almost no motor noise either.
 

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wow nice write upd.... i have the peerless xxls 12 in a 1.6 cubic seal... and i stuff the box of with a whole pillow case of polly....
 

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Discussion Starter #84

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Nice write up, thanks for taking the time to post your findings. Did you try an RTA measurement with the subsonic filter defeated?

I'm considering a replacement sub that has the low end covered, and this in a sealed or the 10" version in a ported is a contender to replace my Boston G310 in a 1.25 cuft net ported.
 

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Someone made ​​a serious comparison with the Velodyne DF12SC? Velodyne anyone ever used this power to make a brief comparison?
 

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So I'm listening to my stereo and I play my favorite old school progressive rock track, you know, Genesis? So it comes to the part where the bass organ gets really low and deep so I crank it up a little and eh? Whats up with this, ahh? Where's the bass?! Ok so I'm not going to give my sub a "bad rap?" because it does smack pretty hard when the music calls for it, it just doesn't play low or so deep. Maybe it needs more than 500 watts, I don't know but all I know is my RTA plot shows I ain't got nuthin below 60 hz or thereabouts- I ain't even got any cabin gains. So I do all this research and read all these threads about the best "SQ" 12 inch subs and all, and you people really know what's doing I can say that much. Basically I built my "box" a little larger than JL specs for a sealed enclosure but the sub models with a rather high F3 (the frequency where the output is -3db and output begins to decline by 12db every octave below that frequency). So my current sub has an F3 of 47 Hz, which seems quite high for a sub roll-off frequency- if you want deep low end bass and your vehicle exhibits minimal measured cabin gain.
So I hit the online catalogs and spec sheets looking for a 12" sub that can model with as low of an F3 as reasonably possible for the enclosure size I have and with a "Qtc" of .707 or as close as possible.
So playing lower frequencies is definitely on the priority list.
Then I starts readin about these subs that seem to "blend" and that you can't tell if its really playin, you know like transparent? Hmm, sounds a little strange but I read on... after all, my sub seems to be a bi-personality- it's either disappeared all the way or it's really there, too much "there". I would have to say this ain't your typical HQ SQ. Sos I add "blending in" and "SQ" to my list of upgrade priorities.
I starts readin about these subs that are "musical" too. Most of them are from over by europe or so it seems. Not bad. I read about this Morel Ultimo. Minga thats an expensive sub. I aint payin that much even if it is made in Italy. Then I stumble on Peerless and Scanspeak subs. Hey, I had a scanspeak tweeter and they was high line. So I plug the thiele small parameters into the spreadsheet and voila, the ScanSpeak Discovery 12" subwoofer would give me an F3 of around 37 Hz with a Qtc of .72. Ayy, I been doin lots of looking and this aint too bad. So I go with it and see what happens.

As yous can see by the attached pics this new ScanSpeak sub seems smaller than my original JL. Marone, the surround is nearly twice as big! The magnet seems a little smaller as does the install height. The frame on the Scan is nice and sturdy being a casting vs. the JL stamped sheet-metal design. Missing from the Scan subwoofer flange is any sort of sealing material (The JL sub has a nice rubberized sealing surface on the flange). I'll have to make a foam sealing gasket. The terminals on the Scan are standard variety 1/4" male connecting terminal vs. the JL spring locked terminal so I'll have to crimp some female connectors to the sub box wiring. As I'm ready to button it all up I notice the mounting holes on the new sub line up exactly with the old ones, so I am thankful for that.

So there's the pic of the sub "in-situ" if you knows what I'm sayin which means I am ready to actually hear how it sounds.
After a few errands drivin around and tuning it in it seemed very weak. Must be breakin in or something. Then I put on my old Genesis CD. Fast forward to the bass organ at the 7:00 mark of "Firth of Fifth" off the Selling England by the Pound CD (at this point you gen X, Y and Z'ers are going like WTF? right?) so ayyy, learn something ahhh? Anyway the bass organ came back to life! Not overpowering but deep and low nones the less. Then I put in a few other CDs with deep low bass and a sumthin a little familiar is goin on- oh yeah, it sounds a little like the JL sub when i had it in this big ported box the size of a small refrigerator. It was tuned to 30Hz. So the low notes are back! But the SQ so far ain't muddy or loose like the ported box sometimes sounded.

Goals of the Sub Upgrade-
1) Lower frequency output.
2) Better overall SQ.
3) More musical, less over the top.

So I'm gonna let this thing play for a few weeks and let the sub break in, tune it a little more, get some experiences with it. Then I'll do some RTA measurements and report back with some updated info and see if the upgrade goals were achieved. Off to a good start though, I can say that much.





Marone is right.
The Scan-Speak 12" drivers (aka 30W series) want to be in sealed enclosures with a volume no less than 1.3 Cubic Feet. I have a Scan Speak Silver 30W Automotive Subwoofer and spoke to Scan about recommended enclosure volumes. If you can go a little larger, do it. Driver displacement is ~.08 Cubic Feet. I line all enclosure walls with ~8mm acoustic felt and there is a sheet of MDM3 damping material in there also (synthetic polyester mixed with wool).
I will post pictures soon. If you build the enclosure correctly, without stuffing, the F3 according to most subwoofer enclosure software is ~38 Hz.
 
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