My First Sub

[---k---]

More photos

Here are the sides with the steel attached and screwed.



I'm not sure the steel was worth the hassle. I know I did it the hard way, but it was a pain in the butt. Drilling and screwing took a ton of time. And, when I pre-drilled, the drill had a tendency to pop the steel loose at a few places. Not quite sure why I didn't get good bond, likely the steel wasn't perfectly clean when I adhered it. I would add some gorilla glue at those locations and clamp it. I was close to giving up on the screwing several times, but I figured if the drill would pop it loose that easily it would be better to have it screwed. And, as long as I re-glued it, it should be all good.

I initially used self drilling metal screws as recommended, but wasn't really happy. The screws wouldn't draw up tight and really hold the steel. It was also easy to strip out the hole. I switched to some 1" drywall screws, and it seemed to work a lot better.

Here is the front baffle:

Image not available
NICE HOLE!
You can see how it is a little short on the one side. I can either trim and add a piece of 2" wide piece or mdf along the edge, or just leave it and fill with bondo. I'm leaning towards bondo. The more I cut and trim, the deeper of a hole I dig for myself. I really need to work on my carpentry skills.

Here is the sides and bracing glued up:



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The bracing is pretty snug, and I used wood glue to attach it. I was planning on screwing it also, but I built it out of 1/2" mdf, and it splits soooo easily. So I just glued it. After the wood glue dried, I added the liquid nails all along the perimeter just to give it more strength. I'm still thinking that I should have screwed it, but if I split it now, I'm screwed.

I saved about 4 lbs making the bracing out of 1/2", I don't think it was worth it. I am glad though that I went ahead and made the sides from a laminate of two pieces of MDF. It give a little more tolerance to my errors. If I split the outer layer screwing, no biggie, the inner layer is solid, and I can just squirt some glue in the split and clamp. May not be perfect, but good enough.

Here is in room:



Man is it big. It didn't look this big on my sketches! I reminded my wife that she approved the sketches, but she says that she could have used a cardboard mock-up. hehehehe
If I can get the finish to be half way decent, it should look good.

I'm off to the store to buy my third 16oz bottle of Tightbond and some bolts for the driver.

[ThomasW]

Looking good ..... :T

That's too exposed a location to use Bondo, one good bump and it will break off. Glue in a piece of wood instead.

[SteveCallas]

I'm not sure the steel was worth the hassle. I know I did it the hard way, but it was a pain in the butt. Drilling and screwing took a ton of time.

When it's all said and done, you will likely find yourself wanting to build more. So I say do as much as you possibly can while you can and enjoy the actual process of building these. I'm sure they will turn out great - but then you're kind of screwed, as you'll have no reason to build more

[---k---]

Thomas,
I took your advice. I trimed the edge so that it was flush, then cut a peice of 3/4" MDF about 2" wide and glued it along the edge. It is oversized, so I'll have to trim it. I didn't feel well yesterday (I only wish I could say it was from partying, but my wife and I enjoyed a very quiet , borning new years), so I didn't get much acomplished. I'll try and get the router out tonight and trim it up and glue the front baffle to the sub. I really need to get these things complete. I got two differnt sets of speakers being delievered soon, and need to have this project basicly done before I start on another.

One thing I did accomplish this weekend was realizing that while the holes in the driver are very very close to 1/4" dia, they arn't. I couldn't fit the 1/4" bolts that I had purchased through the holes. I ended up spending $18 on #10 t-nuts and bolts at Lowes, because they only had the crap in baggies of 2 for $1.34/ea. grrrr. I guess I could have enlarged the holes in the driver slightly, but I wasn't going there for my first project on a driver that has never been used.

Steve,
I mentioned to my wife that I had learned a lot and was looking foward to redoing the boxes so I can make all the improvements that I've learned; the stare was deadly. I am totally thinking about trying my hand at some bookshelves one of these days. The only thing that is really holding me back on building speakers is that I don't think I really know what I like, know what I need, and don't have an ear to really judge what is better. I hope to change that later this month when I have a half dozen very differnt speakers in my family room.

[SteveCallas]

One thing I did accomplish this weekend was realizing that while the holes in the driver are very very close to 1/4" dia, they arn't. I couldn't fit the 1/4" bolts that I had purchased through the holes. I ended up spending $18 on #10 t-nuts and bolts at Lowes, because they only had the crap in baggies of 2 for $1.34/ea. grrrr. I guess I could have enlarged the holes in the driver slightly, but I wasn't going there for my first project on a driver that has never been used.

The holes on the Avalanche driver weren't exactly 1/4" either - I just used a 1/4" drill bit and made the holes 1/4".

[---k---]

I drilled the driver holes and attempted to install the t-nuts. I'm a little dissapointed. Chris's router slipped when cutting the hole, and the cut from the top ddn't perfectly match the cut from the bottom. And, the rim on the driver is so narrow, my holes are real close to the edge. In fact, some of the t-nuts hang off the edge of the little plywood peices. I'm not really sure how mch of it was because the hole is off and how much is because the drive rim is just so narrow. I think it is more that the rim is so narrow. But you guys don't seem to have problems, so maybe it is me.

Are there any tips you guys can give me for when I go to do the other one?

[ThomasW]

The only thing I can think of is to use pro-sound clamps.

Scroll down and see part number G0790

http://www.usspeaker.com/speaker%20hardware-1.htm

[cjd]

:P

Router didn't slip. The guide pin hole wasn't perfectly square and the router bit too short to make the entire cut in one pass from one side, so it had to be flipped. That's just how it goes with that. You can clean up the difference with a flush-trim bit, but that doesn't solve your particular issue.

It may be an issue with the through-cut being slightly larger than it needs to be. Or, it could just be an issue with T-nuts sucking and needing lots of surface to grab, and that surface simply not existing on that narrow rim. I think the through-cut is likely fairly close, so it's the latter. The slightly-off cut doesn't help though, I think.

FWIW, I had this same problem when I did the Tumult for my dad - the issue is with T-nuts more than anything. I hate 'em. That said, get some epoxy. You can place the T-nuts, validate that they're not actually too big to even FIT around the driver rim, and then build up a bit of epoxy to make sure they stay secure.

I believe someone posted an interesting project below that may give you some alternate ideas on how to deal with this. Think it's the "system I just finished building" thread (or something like that.

C

[---k---]

Chris, of course, describes what happens more accurately than I did. I think he is right, that it is just that t-nuts need a lot of surface area to grab, and I have a narrow rim.
I'll add a little epoxy, try and be careful with how much I crank on the nuts when tightening the driver down, and see how well it holds the driver.

I guess I could always re-do the front baffle 8O

I don't know how some people crank these things out in a weekend. I can't get my glue to dry that fast!

[cjd]

I don't know that re-doing the baffle is going to buy you much.

Check out the thread I mentioned - I believe he may have glued a dowel to the backside of the baffle, with the T-nut well secured in the dowel. I only glanced at the photo but it was definitely interesting.

You may also be able to use threaded inserts instead of T-nuts. I MUCH prefer those. Much much much. Much. Muchly much more. I hate T-nuts, can you tell?

C

[---k---]

Chris, just to make sure I understand you, do you hate t-nuts?

I think it is this thread you are referring to: https://www.htguide.com/forum/showthread.php?t=17500

Yeah, I just looked at what he did. Interesting. It is too bad that these parts aren't more readily available at Lowes, etc. so that I could do some experimenting. However, at this point, I'm soooo close, I just want to skip this part and glue the front baffle down and listen. Even my wife just wants to hear the thing. This is hard.

[cjd]

Yup. That's the thread. Look at the "broomstick" pics (43-45). He is actually using a threaded insert here, something you may be able to do in your box *without* the added dowel.

If you can't find inserts at HD or Lowes, you can find them at Ace Hardware for sure. Their selection of this kind of stuff is far superior. And they have inserts. I've purchased them there.

C

[WLF1]

It appears that elfranche used yellow glue to hold the inserts. I think it would be better to ese epoxy and also roughen the outside of the insert to get a good bond to both the steel and MDF.

An alternative to using inserts is to use epoxy to make your own insert in-place. Drill a hole that is the same or larger than the OD of the bolt. Spray the bolt with silicone and let it dry. Then embed the bolt in the hole with epoxy. Let the epoxy set to the point where it has gotten hard but has not reached full cure. Then back out the bolt and let the epoxy fully cure. If you wait too long it will be much harder to remove the bolt. If this happens, use some heat on the bolt to soften the epoxy and make it easy to remove.

[SteveCallas]

---k---, I hope this isn't coming too late, but there is a simple solution to your problem. Cut some plywood rectangles, maybe 1.5" x 3" or 2"x4", and glue two of them together. Now position these over the backs of the driver holes on your existing plywood so that one edge of the rectangles overhangs the driver cutout by just a bit - just enough to securely and tightly fit the T nuts in them. Glue the rectangles in place - when dry, screw through your existing holes to get to these rectangles. Now use the T Nuts in these plywood blocks.

I did something similar but on purpose - the idea was suggested by Thomas. I have my 3 layers of MDF and then 3 layers of 2"x4" plywood behind the MDF over each of the 8 driver holes.

Will this work for you?

[---k---]

Yeah, I used the little plywood peices. But for some reason, when I glued the peices down, I lined them up with the edge of the driver hole. So, it really didn't change anything. I could have let the ply would hang off the edge of the driver hole for four of the 8 holes.

I think it will hold the way it is. I just could have done better. I got a second sub to assemble, so I'll probably do a few things differntly.

[---k---]

I got the front baffle glued and sealed last night. Another tip I haven't seen (but probably is here somewhere) don't pump out a bunch of silicone sealant and then stick your whole head in the box without a N95 mask or respirator! Wow, burned a few nose hairs!

I will be wiring up the first driver tonight to do some basic listening. I got some basic weather stripping to install around the driver rim, some R30 for lightly stuffing the box with, some leftover 14ga speaker wire that I'll solder to the terminal box with some silver solder I got from RS and then just bare wire into the driver.

Does anyone have any tips or cautions? Or is this the easiest step? I got a $15 gift card to RS, that if anyone has tips on how best to use... maybe the 12ga hook-up wire?

Do I need to worry about keeping the R30 away from the driver?

After I get the second box down, the drivers will be removed to do some sanding/bondo/and primer. That is why I figured I would only lightly stuff, so I could remove it and vacume out the box or whatever as needed. Final paint and finish will probably be somewhat down the road when I figure out what speakers I'm keeping, so that the finish can somewhat match.

[ThomasW]

For wiring inside the box 12 or 14 gauge is fine. For the run to the amp use 12 gauge.

Don't 'fluff' fiberglass. One only 'fluffs' dacron. Just gently push the fiberglass through the driver cutout.

The natural resistance of the 'glass' will keep it away from the cone

[SteveCallas]

I'm probably being overly cautious, but since you will have stuffing in the sub might you want to consider using that $15 to buy ring spades/bananas/female disconnects or some form of connector instead of using bare wire at the driver ends and solder at the terminal ends? That and also wrapping any "open" conductor area with electrical tape?

[---k---]

Steve,
I don't know. That was part of why I asked. ops:

I didn't think that I could do better than solder at the terminal end, and the driver has a pretty nice binding post so I didn't think I needed anything fancy there. I always thought that the nice connectors, such as banannas, were more for convience.

[ThomasW]

Tin the wire, insert it in the post and bend it 90 degrees to keep it from vibrating out

[SteveCallas]

Yeah, I didn't mean for better signal transfer purposes, as bare wire would offer the absolute least resistance - I meant more in terms of not having bare wire exposed next to stuffing. I don't know whether that is a valid fire safety concern or not. With a connector, you can wrap any conductive surface of it with electrical tape aside from the very small area that touches the binding posts.

[Dennis H]

R30 (fiberglass) doesn't burn.

[SteveCallas]

I see, thanks.

[---k---]

One Done!



(more photos in that directory if you are interested)

Done and working. I'm not sure I can really post an opinion of how it sounds yet. The first thing that I tried to use it on was The Incredible's. It was most disappointing at first. I thought that the amp wasn't working because I just wasn't getting much volume from the sub, but it was moving. As the movie went on, I started to get more and more from it. I guess it just needed to break in a little. I'm getting okay volume out of it now, but it is no where near what I expected. Hopefully it is just a matter of time.

One thing that I've noticed is that the Signal light on the amp rarely comes on. I can feel the sub, so I know it is getting a signal, it just isn't very strong. Can this be because of the RCA to XLR cable I got? Would it be better to use an RCA cable with a 1/4" adapter on one end, or does it really not make much of a difference?

[PoorboyMike]

Hi Ryan,

Looks like you have close to the same set up as I have. Is that a Pioneer 1014? If so, what do you have the crossover set at and what is the level of the sub at?

I just finished roughing in my 3.5 cf sealed box for my BP1503. I have the RCA to XLR adaptor going to a Rane eq and than just a 1/4 mono from the eq to the amp. I have the input maxed on the eq and the output at the minimum setting going to the amp. With the A Channel on the amp at about 3/4 volume, (and B at 0 just like yours) I have to set my reciever at -10 for the sub out or it's too much bass for my room.

Seems strange that you aren't hardly getting the signal lights to go on. Do you have the amp bridged or are you just using 1 channel?

[SteveCallas]

Did you calibrate the sub at all?

As for the signal lights, I would think that largely depends on what your sub out level on your receiver is set at and how loud you are listening. Mine don't come on too much with music, but they do with movies (I run it hotter with movies).

I used my sub only for the music the first week to get a good feel for it, and then used the machine speaks scene from Matrix Revolutions as the first movie test. If you have that, try it out - you should get a great effect from that scene if you are coming from a not so great sub.

[---k---]

Mike,
It is a Pio 1015TX, but same thing. The crossover was set to 80Hz. I started with the sublevel at 0, but played with it. I had the amp about 2/3 of the way up, in stereo mode. On the receiver, it seemed like I needed the sub channel up +3 or more for the sub to really kick in. I turn the amp up to 3/4 the way briefly, and it was louder, but not a lot. It seemed like turning up the sub channel on the receiver had the biggest effect. This confuses me, because I read about people running thier receivers at -10 and then the amps up. I don't think I would have got a thing out of the sub like this.

I know I've read somewhere that a rca-xlr cable has some problems with signal levels, so maybe this is part of the problem. I'm not sure if rca-1/4" will be any better though. Or maybe it is the piss-poor job of soldering and tinning I did. It was cold and dark in the garage, and I could have used a pair of helping hands.

Or maybe it is just the sub needs to break in some more. I'll do some more listening tonight. Maybe stop at RS and pick up some 12ga wire, female spades, bananas, get the inside wired up better, and also pick up the rca-1/4" adaptor. See if any of that makes a differance. Because right now, I'm not even getting the same level of output as my old 12" with a 180w amp. I expected one of these to be shaking the wall paneling.


Steve,
I didn't calibrate it. I usually can get close by ear, and when I first hooked it up, there wasn't enough there to calibrate. After a few minutes there was more, but by that time the Wife and I were skipping through Incredibles. I'll get out Avia soon.

I don't really have a movie collection. I have Netflix. I'll move Matrix Revo to the top of my queue.

[SteveCallas]

Amp 2/3 of the way up and sub level at +3 and your old 12" did better...hmm, what is the input sensitivity of that amp?

[Dennis H]

Just turn the receiver's sub level up until it sounds right. Pro amps are used to having a high input voltage.

[cjd]

Also, just to be sure... these are dual VC drivers, right?

If so, you have the VC's wired correctly?

Been there, done that... most of us have I think.

It could also be something in the cabling, to be sure. I remember CJ Paul was having horrible trouble with his IB when he was running all four drivers, but things sounded great with just two. Turns out it was a bad splitter cable.

You can try running a full range signal to the sub (just bypass your receiver entirely, connect the source to the sub) that you know has bass content as well - sometimes that helps eliminate trouble spots.

[ThomasW]

As Dennis said.......

Turn it UP! ..... :B

[---k---]

As Dennis said.......

Turn it UP! ..... :B

Well, there you go. I guess I have found my solution.
(I'll still check on the wiring and stuff to see if it makes a differance)

I just was hoping that I could lower the sub level on my receiver, so I wasn't working it's amp so much. Maybe once I get the BFD in the loop, this won't be such a big issue, since it has the switch for Home or Pro input.

[cjd]

You're not going to be working your receiver much at all cranking the sub output since it's a pre-amp level signal. The main channels will be MUCH harder on it than this output. So don't worry about that!

And, especially if you're trying to troubleshoot an issue, you're looking at short term "stress" well within the design parameters of the equipment you're using. So, once again, don't hesitate to crank the receiver output level.

C

[---k---]

You're not going to be working your receiver much at all cranking the sub output since it's a pre-amp level signal. The main channels will be MUCH harder on it than this output. So don't worry about that!

C

You know, that makes a lot of sense. I've never thought about it it being a pre-amp signal. I have read so many times about people cranking the sub amp up while runnning their receiver at -10 to supposedly reduce stress on the amp and to get the cleanest signal, that I just accepted it. Goes to show... You guys are soooo smart here.

[PoorboyMike]

Bridge that sucker and crank it all the way!

That's how I have mine and I have my sub out set at -10 for music and -5 for movies. It does scare the crap out of me watching how far the woofer travels though. It lookes like it's going to fly right out of the box. 8O

[---k---]

Mike, you must have missed it, I can't bridge the amp, because the second channel is going to go to the second one of these bad boys, that I hope to have completed this weekend. hheheheheeh

[PoorboyMike]

Mike, you must have missed it, I can't bridge the amp, because the second channel is going to go to the second one of these bad boys, that I hope to have completed this weekend. hheheheheeh

Yeah, I know about the second one. I was just thinking you could bridge it for know just to give you an idea of what that sub is capable of.

BTW, looking good so far. This stuff is fun isn't it!

I'll post some pics of my build soon along with some frequency plots once I figure out what test tones to use. I don't like the ones I have now because each wave file covers 10hz in 1 hz increments, each one 10 seconds long. I don't have enough time to plot it out and quickly loose track of what frequency it's playing. It looks very similar to yours so far. Mine will be down firing once I get some legs on it though.

[---k---]

WOW!!!

8O 8O 8O 8O 8O

I don't know what the heck I did, but I got BASS!
I listened to a CD or two this evening, and it sounded better. I ran the Pio AutoCal, and it set the sub channel to 1.0 with the amp at 2/3 up, so it looks like it is working. I should have watched a movie at this point, but music still didn't seem to have overwhelming bass, so I pulled the driver to check my wiring. It was fine, but I cut the tinned ends off (I don't think that this was the problem, because of the AutoEQ setting of 1.0, but could have been) and reinstalled. Then listened to briefly listened to some tunes, and then put back in Incredibles... WOW!

I was listening at a normal level, the receiver was at -16 and it was wow. I then turned up the amp for fun to about 3/4 . hehehee I was hitting 95db uncorrected on a RS meter. It was just begining to pressurizing the room. After skipping through the movie to all the bass parts, I was starting to feel it in my ears. Ooops. One of the coolest parts though was the right before the jet gets shot down, it flys across the screen. I think I hit 100db here. It was cool, because it wasn't an explosion. I could also really
tell how much cleaner bass this was than my old 12". It didn't rumble as much, and little explosions, like the exploding message were short and powerful. Very nice.

My wife is scared. She says that she could feel it in the upstairs bathroom countertop, and that "floorboards were shaking".

Hhehehehehhe. I can't wait to get the second one done.

Thanks all. I'm Happy.

[---k---]

Quick question,
When I pulled the driver, I could really smell the GE silicone I that I used to seal the edges. I read hear that the outgassing fromt regular silicone can damage a driver. Is this true? Should I pull the driver and let it cure more? Or is this just bunk?
Thanks

[steve nn]

WOW!!!

Good for you -K-! I have been following your Thread and have felt somewhat of a vested interest considering I have two of the SS Rlp D2 drivers sitting next to me slotted for a 4.5 cu ft sealed enclosure with incorporating Bassis/LT.

As far as your pro goes...don't worry about cranking it like suggested. It's better to crank it (they like it) rather than turning your subwoofer setting up to far on your receiver and introducing distortion. Might I suggest shooting for something like -8 to -2 on a scale of -12 to +12 with adjusting your pro accordingly.

Congrats! and now I'm really enjoying your progress in your DIY endeavor for great bass. 8)

[SteveCallas]

Yeah, the theory behind keeping the receiver's sub out level low and amp's gains high has nothing to do with stressing the amp - it's because with a quality amp you are less likely to get distortion by running the amp gains high than you are boosting the sub level on the receiver. That's the theory anyway. Bob Lee from QSC seems to disagree with it, so I've set my sub level to 0 (used to be around -6) and then adjusted the amp gains from there.

Glad to hear everything is working fine now. I'd probably go ahead and pull the driver out and give the enclsoure some air for that caulk to cure - better to be safe than sorry. Not listening to the finished sub will give you more time to finish the other one anyway

[ThomasW]

My wife is scared. She says that she could feel it in the upstairs bathroom countertop, and that "floorboards were shaking".

This is a VERY postive sign...:wink:

You might want to let the box air out a bit. Since it's winter the silicone won't quickly cure. Might try blasting it with a hair blow dryer, that should speed things up some.

[---k---]

This is a VERY postive sign...:wink:

You might want to let the box air out a bit. Since it's winter the silicone won't quickly cure. Might try blasting it with a hair blow dryer, that should speed things up some.

But that means I have to stop listening to it.

I'm listening to this demo DVD that I got from B&W a week or so ago and haven't really had a chance to listen to. Has some cool stuff on it, with good bass. I recommend it getting the DVD. It was free. There website is down right now, so I can't find you all the link - it was in the 800 series stuff, maybe under sign-up.

[steve nn]

ThomasW> I don't mean to get off track here, but in playing around with FR response regarding driver orientation..I notice I get the best response from firing my driver into the side of our couch over in my preferred corner placement 11' away from seating. It gives me a extra dB of headroom or two along with improving SQ and extension. Was your previous statement meant as a generality or a sweeping conclusion? I also notice I get the best FR response from the down firing options with them placed closer to the couch. I attribute this conclusively to my room and it's characteristics and not that it would be the best orientation for Ben or Jim.

I had been planning on my drivers being placed on opposite sides of the enclosure as to reduce resonance and considering I get good response with either driver orientation. It admittedly has been bothering me even though it was suggested by a DIY'er that has built many. I think I will go with the taller option and put both drivers on the same side considering there has to be some cancellation going on corner loaded. Maybe I should just go with the two separate units like -K- finally decided upon.

[---k---]

Steve,
Sounds like you are ready for a design thread! How about starting one with photos of your room, and where you think you will put these bad boys. (I don't mind the question here, but I think you would get better answers that way)

All,
I'm glueing the second one up, and airing the first one out. Is there any thing I need to do before I start sanding,bondo,primer the first box? I'm thinking I'll hunt down an power sander from someone and start the sanding & bondo. I could probably really use some tips here. Any threads you can point me to that discusses finishes?

As far as primer, I know people like the rust-olumn stuff, but is that really necessary? I would rather roll something. What is the best primer to use? I usually use BM paints.

Thanks,