[HercDriver]

So it's been several years since I've built anything and equally as long since my last post. Work just keeps me too busy... however, I just recently moved and have a small window of opportunity to build a sub for my current set-up before the Air Force throws me back into a non-stop work schedule.

I sat down to my laptop and started doing some research yesterday but 24 hours later my wheels are still spinning. Here is my situation...

I have a Crown XTi 2000 amp to push whatever I build.

I would prefer 2 separate subs but one is fine as well.

Size is not too much of a factor but I'd like to keep it 350ltrs or below if possible.

My room is quite large... 35' wide x 30' deep

I am looking at a passive radiator build with the TC Sounds 15Q1 and their 18" passive radiator but I'm also open to other options. I'd really like to get a good range out of this thing so I tend to lean more toward ported than sealed.

Unfortunately my laptop that had bassbox pro on it for my last build broke many years ago. When I got my new laptop that was the last thing on my mind. So when I went looking for it... you guessed it... it was gone. I'm not buying it again as the military moves me constantly and I rarely build so Im looking for not just advice but as much help as I can get with the specs from anyone who has the time and ability to help me out.

And no... I cant get WinISD to do anything for me. I've ran the numbers 5 times, quadruple checked them and ran it again... nothing seems to be working. It has never worked for me so I always ran with bassbox... It's been SO long that I feel like a Noob again.

This was my last build...

http://www.hometheatershack.com/forums/diy-speakers/12087-finally-finished-revelator-build.html

Thanks again for any help anyone can provide!

 

[HercDriver]

A couple other things:

1. Ceilings are 12'
2. Main purpose is Home Theater use.
3. Speaker/PR are not purchased yet so I'm open to other options.

Thanks again!

 

[Mike P.]

An option to consider is the Stereo Integrity 15D2. A pair of these will outperform and cost less than a single TC Sounds 15Q1.

 

[HercDriver]

Thanks Mike! I'm looking them up right now.

 

[HercDriver]

So Mike, do you mind checking my numbers and doing a quick sanity check on my thoughts?

2 enclosures with a SI 15 D2 in each one.

Each enclosure:

I'm coming up with a 22"x22"x28" @ 4.86 ft3 (1.5" thick material)

Tuning to 22 Hz with 3x ports - 3" diameter x 22" long each.

I'm still VERY new at the subwoofer building thing so PLEASE feel free to jump all over me and push me in a different direction.

Oh and thanks again!!!

 

[Mike P.]

What does the amp put out per channel into 4 ohms?

 

[HercDriver]

It is rated for 800W in Stereo, 4 ohms per chan

Bridge - Mono, 4 ohms = 2000W

Thanks again for all of the help... I've been playing with WinISD for the past several hours but I just cant get it to look just right... but maybe it does and my eyes are just the problem.

 

[Mike P.]

Going ported means you will need a hi-pass filter at the lower frequencies, you can get a Pro amp with DSP that has a HPF at 20 hz, an example would be the Behringer iNuke 3000DSP.

The 3000DSP is 880 watts per channel with a 20 hz HPF, so getting the most output from the driver would be in a 10 cu.ft. cabinet tuned to 20 hz with three 4" ports 23 inches long.

Here's the project file:

View attachment The HercDriver Project.wpr

Here's a comparison of 4.8 cu.ft. compared to 10 cu.ft. The larger cabinet has a lot more output in the 17 to 25 hz range which you need in the large room that you have.

 

[HercDriver]

Thank you so much for taking the time to do that for me Mike. Very awesome of you!

So since it seems to be just you and I... my Crown has DSP and I can set the HPF through HiQ. Do you think 800W per channel is good enough or should I buy a couple plate amps or another Crown/Behringer for the second speaker?

Since I've got ya for a min...

1. Whatcha think of this stuff for padding? http://www.acousticalsurfaces.com/wall_insulation/ultratouch.htm?d=28

2. What volume calculations do you use for insulation?

3. Are two of these 10 cu ft cabinets at 800W going to be sufficient for my room or is there something else you suggest? Size-wise, that is all I can do... but I could easily pull off something like 4x 5 cu ft boxes. Would going sealed and using 3-4 drivers give comparable results to the 2x enclosures we are talking about now?

I'm very surprised not one other person has had anything to say... folks seemed to be a lot more chatty several years ago.

 

[ßart West-VL.]

I'm very surprised not one other person has had anything to say... folks seemed to be a lot more chatty several years ago.

That's because Mike has all the answers you need.

 

[Mike P.]

Not sure what you need that kind of padding for, If you want to line the cabinet then a couple inches of open cell egg crate foam would probably be a lot cheaper.

4 sealed subs with 2400 watts will have less output at 20 hz than 2 ported subs. With 800 watts per channel the 2 ported subs will produce 120 db at 20 hz. How far from the seating position will the subs be? will the subs be placed in room corners?

 

[HercDriver]

True... just very rare that there isn't anyone else dropping their 2 cents. I was actually worried that I may have poorly worded my OP and turned people off.

So Mike - I think I'm going to have to go with 9 cu ft enclosures... 10 was just too big for the WAF. I showed her 8 but I'm pretty sure I can pull off 9 without her noticing much difference.

Subs are ordered and headed to Lowes shortly!

 

[Mike P.]

If you're using 4" flared ports then they'll be 26" long for a 20 hz tuning for 9 cu.ft. net volume.

 

[HercDriver]

I'll def stick with 2x ported enclosures then... that sounds nice. Getting excited now.

As for placement:

I am thinking of putting one on each side of the HT. The two stacked boxes on the left are a marker of where one would sit. The other would sit just to the right of the fireplace... not quite in the corner. That would put them approx. 12' and 16' from the primary listening location.

My other option is to build an 84" long trapezoid box that would sit behind the sofa... but the wife was hesitant. I don't wanna build a gigantic box like that only to have her say no after the fact. :gulp:

 

[Mike P.]

I have an agreement with my wife, if she says yes before the fact then she can't say no after the fact.

 

[HercDriver]

OBTW... the Vent length in WinISD is referring to the effective length of the port, right?

So my tip to tip measurement should actually be:

the WinISD length + the radius of the flare (if both ends are flared)

Is that right?

 

[HercDriver]

I have an agreement with my wife, if she says yes before the fact then she can't say no after the fact.

LOL - Nice. I may have to take that road as well. But It is a big box to have right there. It is a high traffic area for the kids.

 

[Mike P.]

WinISD calculates the port length for a straight tube, if using flares you add one inch to what WinISD states.

 

[HercDriver]

Perfect!

So what are your thoughts on cabinet wall thickness?

I plan on building a 35" wide x 35" tall x 20" deep enclosure. Front wall will house the woofer (35"x35" surface) and will be doubled up in thickness. I plan on having 3 or 4 horizontal braces and 2 vertical braces.

So my question is... should I make all of the walls 1½" thick or just the baffle? I have no problem doing it either way it will just make for a MUCH heavier box if I double up and I don't wanna do that unless it really is something that needs to be done.

Second question - are there any pros or cons for using a 90 degree turn in the ports? I have ample room to fit the ports on either of the 35" axis but I think it would look much better with the 3 ports on the same surface as the woofer...

 

[HercDriver]

In regards to my second ? above... I think I've got my answer but would still like your opinion on it. I would only be able to do a 90° bend so I am leaning towards no bends in the ports.

Thinking of doubling up only on the front and bottom panels and just adding a bit more bracing. Still drawing and playing with Boxnotes. Hopefully I'll have a thread started in the build section tomorrow!