Well...I'm at it again!!!

[hddummy]

The time has come for me to build another subwoofer!!! This one is for a friend of mine. I'm stoked!!! This will be essentially the same concept as my subwoofer seen here.

http://www.hometheatershack.com/foru...-feedback.html

Here is the plan so far. I will be using a Fi Audio SSD12 with dual 2ohm VC and an O-Audio 500W Bash amp. The box will be roughly 4.25 net cu.ft. and tuned to the 18-19Hz range. This one will also have an up facing driver The ports will either be in the top face or on one of the short side walls.

Comments/Suggestions about the hardware????

[Sonnie]

I'll be looking forward to your progress reports...

I also moved this to the Fi Audio forum, but I left a redirect from the other forum in place for 30 days.

[Mike P.]

Sounds good. Make sure to post some build pics.

[WillyD]

Do you already have the SSD12? If not, FiAudio may still have some of these X-series drivers left.

http://www.audiojunkies.com/blog/712

A pair of 12" X-series drivers for $160 shipped! Those in 8ft^3, VCs in series, drivers in parallel, tuned to 20Hz with 3 4" ports and hooked up to that Oaudio amp with the SSF set to 20Hz. Yeah, that'd work.

[hddummy]

Thanks for the suggestion, but I definately don't have room for two 12"s. Maybe two 10"s, but they didn't model quite as well as a single SSD12". That does look like a good deal though!!!

[Fi Audio]

Plenty of X series drivers left. If anyone is interested in them I can post up info about them and even give a little further of a discount for the HTS forum members.

^ These sound interesting, I would like more info.

[Fi Audio]

The X series drivers were designed as our "entry level" car audio sub. They have 16mm of Xmax and 250W RMS power handling. They come only in dual 4 Ohm coil configurations so they can be wired for a single 8 Ohm load per driver or in pairs for a single 4 Ohm load.

As they were car oriented they tend to push for EBS alignments in most home applications. They make for a nice home sub, but not particularly a ultra deep HT sub.
There have been a couple of people that have done 6 cuft enclosures tuned to 23 Hz for home/music use using some of the common plate amps out there. As many have a SSF set to around 20 Hz it seems to work well overall.

Specs for the X12 are:
Fs 25.7
Re 3.9 Ohms per coil
Qms 4.01
Qes .38
Qts .35
Sd 481 cm^2
Vas 104.1 l
Xmax 16mm
BL 20
Spl 88.6 1W/1m
250W RMS

Specs for the X10 are:
Fs 25.9 Hz
Re 3.9 Ohms per coil
Qms 3.90
Qes .35
Qts .32
Sd 310 cm^2
Vas 45.7 l
Xmax 16mm
Bl 20
Spl 85.4 1W/1m
250 W RMS

Both work well in mid/low 20 Hz builds in medium enclosures. They are well suited for music applications, but not as well for ultra deep HT setups. You could make some decently compact mid 20s tuned music/computer subs with them as well.

Ill see if I cant get some multi driver deals going if people want them as well...
Thanks,
Scott

[hddummy]

Sorry for the wait. The holidays are always a busy time of year. We finished the sub and I will be tuning it this weekend once the rest of his speakers show up.

[Mike P.]

That's a good looking sub, Matt! What finish did you use on the cabinet?

[hddummy]

Flat black latex paint.

[Ricci]

Nice job! That is a good looking sub.

[Fi Audio]

Good looking setup. Please keep us posted as to how it sounds when you get everything together.

Thanks,
Scott

[Sonnie]

I am terribly impressed matt... that thing looks good... great job.

[hddummy]

I'm going to wait until I get my new sound card for my computer to dial this thing in. In the mean time, here are some new pics with the new speakers. Sorry for the bad stich job, but you get the idea. The speakers are all Polk Audio.

[Captain Crunch]

I really like the design ..........and it looks great! A++

[Geoff St. Germain]

Another great looking subwoofer Matt! I'm very interested to see any measurements you take.

[Owen Bartley]

Matt, really nice work! I especially like the angled ports with internal AND external flares. Seems like your design is a killer space saver for people with TVs located in the corner. It must also be fun to watch people look around trying to figure out where the bass is coming from! Can't wait to hear how it sounds.

[hddummy]

The question was asked of me in a PM about how I connected the flares to the PVC tubing for my ports. The explanation is longwinded, but I hope it is clear enough to help.

It was a bit tricky and I would look for a better way if I had to do it again. Hopefully, this will give you a starting point to improve upon. All of the white parts are PVC. The black flares are from Precision Sound Products purchased through ThrillerAudio.com. As you can imagine, these parts are not made to fit together. We could not figure out a good combination of PVC parts and Precision Sound parts to make a tight fit that could be glued with just PVC cement.

We tried layering the Precision Rings and we tried routing the inside and outside of PVC tube, but nothing really worked. The ideal solution would be to build up the OD of the Precision port to fit the inside of a PVC Union. Here is what we came up with.

We started by cutting a Precision Connecting Ring around its circumference so that it was half as long. We then glued the ring to the end of the flare.


Next we glued a PVC Union to the end of the PVC Tube. We inserted a cardboard tube into the PVC tube as shown. If you don't have a cardboard tube that is the correct OD, you can take one that is a little bigger and cut a lengthwise strip out so that it will collapse down to the correct OD. Actually, you could use pretty much any material, so you might find another piece of PVC the right OD.


Next we filled the cavity with adhesive. We used a water based construction adhesive from Home Depot. Regular Liquid Nails would work extremely well, but cleanup would be a PITA.


Next, insert the port into the adhesive filled cavity. There will be a lot of adhesive squeeze out. This is where the water based adhesive really pays off.


Finally, pull the cardboard tube out of the center and clean all the excess adhesive. Do this before it starts to dry or the inside of your ports will look terrible. Be careful though, because once that tube is out, there is nothing holding the port in the center of the PVC Union except the adhesive. The adhesive does provide quite a bit of support though.


Let it dry over night and the next day you will have a quality flared port on the end of your PVC tube. Good Luck!!!

[hddummy]

Finally had time to go and measure the response of this sub. I am definately pleased. The amp has an adjustable subsonic filter. These three curves are near field measurements with the filter set at 12Hz, 16Hz and 20 Hz.

[Owen Bartley]

That's pretty flat response! So which setting have you decided to stick with? I'm not sure if you have a BFD or not, but if you do, I think I'd go with the 12Hz filter, but a small boost around 17Hz to take care of that little drop, and you're looking great!

[SteveCallas]

With a 12" driver I'd stick to the highest highpass, the 20hz one. Nice work, but please tell me those bookshelf speakers aren't going to stay on the floor?

[hddummy]

we were getting some port noise on the sweeps with the 16Hz setting, so we set it at 20Hz. During movies, there is no port noise on the 16Hz setting though. We calibrated for 20, but I told him he could set it at 16 if he think he can tell any difference. I think being flat to just under 20 is a good achievment regardless of the setting. No...no BFD. The amp has a single parametric equalizer and his receiver has equalizers for 5 or 6 preset frequencies. We used all of the equalizers to get as flat a response as possible at the seating position.

Unfortunatley, there isn't much room for the speakers on the side of the TV. He is going to build some stands to bring the LR speakers up to the same height as the center and also angle them up slightly.

[Owen Bartley]

I guess being flat to under 20Hz is a pretty impressive feat for a 12" driver... in fact, I completely forgot you were just using a 12 and I just assumed it was a 15 until I read Steve's comment. In that case I'd opt for driver protection over a little more extension as well. But impressive results in any case!

[derekbannatyne]

Did you apply the paint with one of those foam rollers? I can never seem to get the finish that flat.