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New build for dedicated 3600 cu ft theater. Two RSS390HF's? Four? Sealed/Ported? - Page 3

post #61 of 79
11/19/12 at 7:59am
if you still have the piece from the brace cutout, it might be a good idea to cut a 2" wide slice from the middle and glue it back in, in order to brace the baffle next to the driver.
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post #62 of 79
11/20/12 at 4:20pm
Thread Starter 
Quote:
Originally Posted by beastaudio View Post

Awesome progress!!! Looking forward to the updates! What was your final design for these?
Just a hair over 5 cubes depending on the bracing I put in, tuned to 20Hz? Building two to start with to see if I'm happy, two more if necessary. They will be disguised as benches in the theater room.
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post #63 of 79
11/20/12 at 4:33pm
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Quote:
Originally Posted by LTD02 View Post

if you still have the piece from the brace cutout, it might be a good idea to cut a 2" wide slice from the middle and glue it back in, in order to brace the baffle next to the driver.

I have lots of bracing material to add. I thought about what you are suggesting but didn't want to block too much of the air travel and decided to brace the baffle in other ways.

I was going to go around the opposite side of the baffle, which is actually the top of the enclosure (since it'll be a downward firing sub), and brace the corners so I can router the top edge without weakening it too much. I'll post more pictures after I get more of the first box completed. I've been waiting for a dry day to cut some of the bracing material I have left in half so I will have all of the pieces cut out for the next box.
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post #64 of 79
11/20/12 at 5:19pm
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I cut the strips for the bracing because I had an extra 15 mins today and it wasn't raining! Of course I just dropped these pieces in but I might decide to move the vertical brace at the end of the box near the sub to the middle of the box where the other one is, for extra bracing in what would appear to be the weakest area of the box (the middle).


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post #65 of 79
11/22/12 at 1:28pm
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post #66 of 79
11/23/12 at 6:20am
Are your ears starting to salivate? Hehe, for pure medical reasons I really hope not, but hopefully you get what I mean biggrin.gif
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post #67 of 79
11/23/12 at 10:13am
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Quote:
Originally Posted by beastaudio View Post

Are your ears starting to salivate? Hehe, for pure medical reasons I really hope not, but hopefully you get what I mean biggrin.gif
Yes but I feel like I have such a long way to go. I need to cut and install the ports, router the edges, fill the holes, sand, primer, paint, figure out the feet, and then do it all over again! Lol...
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post #68 of 79
11/24/12 at 5:58am
That sure is a great design idea. Small subs with nice vaneers are cool, but I love when you can take a monster sub and make it disappear. And what significant other doesn't love more seating?!

Great job! Are you covering it with fabric or pleather? If so, you don't have to worry about sanding etc.
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post #69 of 79
11/24/12 at 8:36am
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Thanks B! I will probably sand it and lacquer it to see how nice I can get it (just for fun) but may ultimately cover it with a thick fabric to keep it protected. Either way I will have cushions on top so you can actually sit on them.
Edited by AI Limited - 11/24/12 at 8:55am
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post #70 of 79
11/25/12 at 4:02pm
Oh. Yeah. Maybe a shiny red paint job? That would be cool.
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post #71 of 79
12/3/12 at 5:16pm
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Originally Posted by brian6751 View Post

Oh. Yeah. Maybe a shiny red paint job? That would be cool.

Well I'll be happy if I get them playing. I have a lot of work to do and with Christmas here... maybe in January!!!
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post #72 of 79
12/3/12 at 7:00pm
Thread Starter 
Port length... just curious... question first: How critical is the port length when dealing with a 5.25 cubic foot box for a Dayton 15" HO driver?

I was doing a little playing today in WinISD and concluded that port length isn't as critical as I thought.

For example: I'm not sure EXACTLY what my box dimensions are because I put in a lot of miscellaneous bracing and estimated the equivalent volume that the speaker itself is displacing at about 1/2 a cubic foot. So if I ESTIMATE a volume of 5.4 cubes, and look at the port length, it goes down to a minimum port length of like 24" depending on where I tune. At 5 cubic feet, it goes up to a maximum port length of about 32" depending on where I tune. Assuming I'm around 5.25 cubic feet of air space, the transfer function magnitude, rear port air velocity, and port gain look reasonable at anywhere from 26"-30" long. Shorter actually looks a little better on the transfer function but worse on port air velocity.

So am I correct that an inch or two difference in port length isn't going to make much of a difference in the sound of the sub? Which is more important, keeping the port velocity as low as possible (reducing port gain) or keeping the transfer function magnitude looking good?

Thanks in advance!!!!
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post #73 of 79
12/4/12 at 7:15am
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Originally Posted by AI Limited View Post

Well I'll be happy if I get them playing. I have a lot of work to do and with Christmas here... maybe in January!!!

Maybe I should've called this project "the slow roll"...
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post #74 of 79
12/4/12 at 10:11am
Quote:
Originally Posted by AI Limited View Post

Port length... just curious... question first: How critical is the port length... I was doing a little playing today in WinISD and concluded...
The beauty of learning to run simulations yourself is that you teach yourself how to answer these questions. I have come to the same conclusion. I think it's what makes subwoofers so popular as first/early DIY projects -with so much latitude, it's hard to get a bad result!

HAve fun,
Frank
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post #75 of 79
12/4/12 at 12:49pm
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Quote:
Originally Posted by fbov View Post

The beauty of learning to run simulations yourself is that you teach yourself how to answer these questions. I have come to the same conclusion. I think it's what makes subwoofers so popular as first/early DIY projects -with so much latitude, it's hard to get a bad result!
HAve fun,
Frank

Thanks Frank. I guess I was looking for confirmation that what I was teaching myself was in fact correct. Had I gotten the response of "Yes but you forgot xyz and if you look at that graph you'll see where you're missing the biggest impact... blah blah blah" then I'd still be learning! Glad you came to the same conclusion and thanks for posting!
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post #76 of 79
12/9/12 at 2:23pm
Quote:
Originally Posted by AI Limited View Post

Port length... just curious... question first: How critical is the port length when dealing with a 5.25 cubic foot box for a Dayton 15" HO driver?
I was doing a little playing today in WinISD and concluded that port length isn't as critical as I thought.
For example: I'm not sure EXACTLY what my box dimensions are because I put in a lot of miscellaneous bracing and estimated the equivalent volume that the speaker itself is displacing at about 1/2 a cubic foot. So if I ESTIMATE a volume of 5.4 cubes, and look at the port length, it goes down to a minimum port length of like 24" depending on where I tune. At 5 cubic feet, it goes up to a maximum port length of about 32" depending on where I tune. Assuming I'm around 5.25 cubic feet of air space, the transfer function magnitude, rear port air velocity, and port gain look reasonable at anywhere from 26"-30" long. Shorter actually looks a little better on the transfer function but worse on port air velocity.
So am I correct that an inch or two difference in port length isn't going to make much of a difference in the sound of the sub? Which is more important, keeping the port velocity as low as possible (reducing port gain) or keeping the transfer function magnitude looking good?
Thanks in advance!!!!

My port length kind of was just an estimate and it turned out I'm tuned to 16 when I was aiming for 18hz, so just try to make it longer rather than shorter. My port length wasn't an exact science. I used the port length I was given from WinISD for a 3" port, but the last 2 inches of my port was 3.5" instead of 3" because I used plumping tubing. Then I added an extra baffle which I never accounted for which made port longer than they sugggested and I was still within 1 hz or 2, so I wouldn't worry too much. But my port length turned out longer than it should have not shorter so take that for what it's worth.
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post #77 of 79
12/17/12 at 12:37pm
Thread Starter 


I put primer on it then decided to go fabric. My Mom is going to sew me some after Christmas. It's a perfect height for my center channel so I may go with a front and back placement as opposed to the sides of the room. In that case they aren't as likely to be sat on, but they will certainly accommodate it if someone does sit on it. I'm going to bang the next one out pretty quickly since it's all cut and I have all of the other materials already.

Edit: Sorry for the blurry pic!
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post #78 of 79
1/2/13 at 11:32am
Thread Starter 
Update:

The second subwoofer is complete. I moved them both to my theater and ordered the iNuke3000dsp. Unfortunately I had originally ran XLR's in anticipation of plate amps so I had to order some speaker wire and will have to pull new cable. I also purchased my JVC projector and Marantz 8801 preamp! My theater should be up and running by the end of January if all goes well!!!
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post #79 of 79
1/8/13 at 2:43pm
Thread Starter 
Well I got my theater room running, albeit only 80% installed. I have to run some speaker wire still but have it draped across the floor for now. The subs sound pretty good so far. I am just running them off of a spare Emotiva XPA-2 with no high-pass filter (so I have to be careful) and equalized through Audyssey XT32. I can't match the levels of the two subs because I have no manual gain control on one channel vs the other until my iNuke comes in (late this week or early next). I need better lighting control but the clarity I have at high volume with the solid bottom end is terrific so far. I have about 15 mins of viewing/listening time in.

Edit: My iNuke gets delivered today (1/10/13).
Edited by AI Limited - 1/10/13 at 9:45am
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AVS › AVS Forum › Audio › DIY Speakers and Subs › New build for dedicated 3600 cu ft theater. Two RSS390HF's? Four? Sealed/Ported?