Ported Blueprint 1503

[Dustin B]

Larger enclosure same port means tuning frequency goes down. How much it will go down depends on what the tad actually is. Fraction of an inch in one dimension, wouldn't worry about it. Inch on all dimensions and I'd be chopping a little length off the port.

[Bent]

Dustin, that's what I thought. Sorta like a pop (beer) bottle...
the bottle with 200ml of fluid is the enclosure, the neck is the port - blow across the neck and get a resonant frequency of "X".
Drink some of the fluid and blow across the neck again and the resonant frequency is a "tad" lower.
I would expect the same to be true of the port. If the box is 6 ft^3 and the port is 26" long (I haven't done this math yet so my numbers are just representative values) there will be a resonant frequency of "X" again. shorten the port a tiny bit "1/2 inch or so" and the resonant freq. will again drop... (this isn't taking into account the gain in enclosure volume abtained by shaving the slight amount of length of the port)

My enclosure will be approx 1 inch deeper than Thomas' box, but my port looks like it's going to be approx 3/4" longer than his as well. As long as this stands a better chance of extending the response I'll be happy. I'm hoping I don't wind up with a higher F3 and hence a response hump somewhere on the response curve.

[Bent]

An update...
I found that it is much better to use a plunge router for cutting these big circles than to keep changing the settings on a fixed base.

I have the port hole in the front recess-base cut, the hole in the arch shaped tombstone thingy, the port holes and driver holes in the doubled up front baffle, and all the port tube holes in each interior brace (including the big mathcing driver holes...).

On the last brace where the rear port flare sits, I routed a nice little rabbit to accomodate the rear flare's "lip" as well as the 9 inch hole to support the "flutes" on the flare.

I still have to cut the driver hole in the front re-base and then start fitting the box together. :T

I'm going to try really hard to utillize the rubber gasket on the BP-1503, cause I really like the way it sets the edge of the driver off. I'll try to use a 1/2 round gasket punch to enlarge the screw holes in the gasket to allow me to tighten the mounting screws easier.

I'm pretty pumped right now.

(I'd have snapped some construction pics, but holy doodle there was a lot of dust - prolly not the best thing for a camera, or me for that matter.)

[JonMarsh]

Think protective mask, at least! Definitely not the best thing for you!

~Jon

[Andrew Pratt]

A dust mask is mandatory when working with a router and MDF! Sounds like you're making progress :T

[Ten 99]

Agreed. It may sound silly, but that MDF dust can cause you some respiratory probs if you keep that practice up. Some wood species dust can even cause inflamation of your lungs.

[Bent]

I did the BIG hole on my front (most outer) baffle - the re-base today. 15.5 inches to countersink the driver. Then I took the evening off.

I brought this piece home today to show the War Dept. I had mocked it up with the port flare, the "tombstone" (still unpainted) flare extension and the 18" wide by 29 inch high baffle.
She was (surprisingly) impressed, and the size of the faceplate for this beast wasn't too much for her to bear. Just wait til she see's the 36 inches that come next, LOL.

[David R.]

Yeah the front baffle is a little deceiving (sp) for over all size.. I was even surprized after assembling it..

Glad to hear things are working out. Interested to know once you start putting the internal braces in.. Sometimes "putting things into things" can be difficult.

[Bent]

Well David - I pissed around with the sides, front baffles, top and bottom today...
you are right about fitting stuff into stuff. I have a tiny bit of trimming to do when I tackle it again (I can't quite test squeeze the doubled up rear baffle into the box yet.) I haven't even tried to do the internal braces, but I did expect to have to trim each one t least once.
I had a couple of moments of doubt about this as my first project today too - but I got over it pretty quick when I started thinking just how hard this thing is going to hit when I call upon it to do so.

Can anybody tell me where I can get the felt cabinet lining material that Thomas used in his AS-15, or would egg-crate foam do the same thing?

[ThomasW]

The 'felt' is actually high wool content felt gasket material.

I buy it from local custom gasket makers (yellow pages). Here I can usually get the end of a roll. I usually pay $8.00+/sq ft.

It's available in the US (not sure if they ship to Canada) from www.McMaster.com (type 'wool felt' in the find box then look at 'sheets' link. The weird numbers (SAE-F1, F8 etc) are the wool content. The lower the number the higher the wool content, and the higher the cost.

You could use the 2.5" thick acoustic foam from PE or elsewhere. I think the wool felt is better.

Many prefer to use raw fiberglass insulation for subs, it has the best bass absorption properities. Personally I itch just looking at it.

[Bent]

two more baffles to install, the front re-base, the port-flare extender and the re-base.

then I haul the beast home and try to veneer it.

this is a VERY substantial enclosure - and I have to load it into my mini-van...

pictures tonight...

[cjd]

FWIW the ADA1200 will not flush-mount into a baffle that's 1.5" thick without a little material removal on the inside to clear that massive transformer! I had to trim ~1/4" deep I think. (it's going in a sealed box with a Tumult). Finished trimming the edges and stained it yesterday.

I also suspect that it will have to be delivered in pieces. Not sure I can lift the thing all put together!

C

[Bent]

cjd, that's excellent.

looks like I'm the slowest subwoofer builder on the forum - I still can't decide on mounting the '1200 on the box...

I really think I'll do it outboard, that will always leave the option of building it in down the road.

B.T.W. all the baffles are now in place as are all the spacers.

tonight I get the rear port flare epoxied in place, and trial fit the front re-base as well as the "tombstone" to get the port tube sized correctly.

[taz13]

or easy to swap amps for test purposes etc.

[Bent]

I guess I'll have to eat crow - my daughter's 9th birthday was tonight, so we had a few of her friends (and their parents - our friends) over for cake (and beers)... Now I can't drive back to the office to snapp the pics. :boozer:

oh well, tommoreow is another day.

[Bent]

no pics yet, and no progress tonight...
(I have a head cold)

I have drilled mounting holes in the front baffle and mounted the driver - the woofer mounting kit I ordered from CSS didn't have long enough allen-key headed screws, so I had to buy longer ones from a local hardware store, a exact look alike but one inch longer. I also installed the blind nuts in the holes (one of them cross threaded, but I had spares) as well as epoxying the rear port flare into place. A test fit of my port tube revealed that the cut-off on the inside end of the port tube wasn't square, so I'm going to have it done on a lathe to ensure accuracy - good thing I have a lot of spare 6" pipe left, as I can't cut both ends untill I have an exact measurement obtained from dry-fitting the front re-base and port flare extension (tombstone), and still need to buy a roundover bit to clean up the outside arch of the tombstone. This will also be painted black prior to installation on the re-base.

I checked how tricky it is going to be to intall a removeable rear panel and with the help of a local gasket place (argus industries), I can get some air tight neoprene rubber gasket stock and make my own rear cabinet gasket, so now I will be installing the amp on the rear plate.

I also want to design some sort of feet for it, should look good...

[taz13]

I have squirrled away some of each of the following: 2" Brass, Stainless and aluminum round stock if that interests you?
I still vote for the outboard amp, even though its yours and there is no voting.

[Bent]

I managed to find a way to make a perfectly square cut-off on the ends of my 6 inch port tube.

for the first end, I simply routed a circle out of a larger square of 3/4 mdf approx 1/8" larger in diameter then the port tube. Sitting this piece over top of the end of the tube (just enough so that the tube's edge sat slightly below the edge of the hole), and clamping 4 small rectangular blocks to the side of the tube in which to but the piece with the hole in it against and then squaring the four rectangular pieces, I was able sit a router with a 1/4 up-cut bit on the flatpiece of mdf and rout around the outside of the tube - leaving a perfect right angled cut.

for the second end, knowing the total length in my case needed to be 22 - 5/8",
I cut the tube off at approx 22 - 3/4" with a jig saw (not a pretty cut...)
I set the same four little blocks' business ends at exactly 22 inches from the previous cut. Now if I place my 3/4 thick mdf plate with the hole I just routed in it on the end so it buts against the 22" point of these little blocks, then my router support surface will land at exactly 22 - 3/4". By setting the spiral up-cut bit to exactly 1/8" cut depth, and having a bit of the tube sitting recessed into the hole already, the next routed cut lands at exactly 22 - 5/8" and still perfectly square.

Slick huh?

here's a sketch (NTS)

[ThomasW]

A clever lad you are Ben ...... :wink:

[Bent]

Well guys, I have my front recess-base installed, as well as the tombstone port flare extension. I had to flush trim the re-base before installing the tombstone, and since I used store bought laminated pine panels, I just happened to have a knot land on the very edge where I was going to flush trim the pine. And damnit, didn;'t the knot go and tear out!!!! (sad face here.) - however I opted to soldier on and keep working, thinking that the gouge would probably add character anyway (no use crying over spil't milk). I tacked down the tombstone with some more glue, clamped it and locked it up for the night.
Tommorow I get a couple of friends to help load it up in the racing beige minivan and take her home. I still have to install the tube (which fits perfectly, B.T.W.), and glue/epoxy/clamp the front flaer on - not to mention paint the tombstone black and clear coat the pine. I know I should have done this before assy, but my large boss was getting on my case about this big heavy box in the cold (but insulated and heated) storage building. I should be test running the amp in an un-lined box in two days - and if the amp works, I'll be buying some eggcrate foam locally this weekend. :T

[Bent]

today's update...

front port flare and port are installed. !!!! It looks like a sub from the front now.
(except the port is still that ugly green colour.)

And cjd, you are dead right about the ADA 1200 not fitting. so that makes it easy to decide to go outboard... and I think I know where to find a box made of 16 guage steel to mount it on.

Now I'm going to need an input cup with some classy terminals.

(late edit here)
I could also remove the torroid, and mount it on four 1 -1/2 inch threaded standoffs, this would give me enough clearance,
I'd have to contact Adire first though, as there are three wires with flag connectors that would need to be extended - all the other applicable wire harnesses are of suitable lengrh.

[Bent]

OK, I lost some of my ambition, and took it home...
I haven't fixed the rear panel with the amp mounted on it (what a job that was, with the torroid being in the way - I made a heat sink extension to allow clearance.), but it seemed to be a tight fit, so I powered it up with a LFE signal available - It wistles like a bugger...

I also think I may have to examine my port assy for chuffing, as there is some noise, but I can't quite locate it for sure what with the noise created by the rear panel leak!

I guess I have to weatherstrip it and screw it down.

But it is way louder and lower then my old PSB. :T

[Bent]

Well guys, here it is:



I sealed the rear panel leaks with some closed cell foam weatherstripping, and found the chuffing sound was coming from the joint between the front flare and the port tube, I guess that pipe cement wasn't necessarily the best for sealing it, so a quick schmeer of clear acrylic adhesive caulk made it quiet as can be.

Now I need to paint my flare extension, paint my port tube (the Dept. of domestic afairs doesn't care for a large peice of green sewer pipe in our rec-room.), and get it veneered. You can also see where the knot tear is on the left side... Any suggestions about reparing that prior to veneering?

[JonMarsh]

If you're talking about veneering, as in the pine will be covered by veneering, then fixing the knot tearout is simple... bondo is your friend. It's an unusual and lucky cabinet project that doesn't have a little bondo somewhere...


~Jon

[taz13]

Instead of paint why don't you make a ring that will fit over the extension and cover the flare with grill cloth in the approriate colour or make a grill to cover the front, by mounting some steel washers in the baffle you can then use some rare earth magnets in the grill frame to mount a grill in Dept of Domestic affairs approved colour. Then nothing gets pushed into that cavity, small people, animals, children etc. If you don't want to buy bondo, use some 2 part epoxy to fill the dings, little harder to sand, but you probably have some.

[ThomasW]

I don't think pipe cement is designed to glue ABS to PVC. The flare is ABS, the port is PVC. I just used hot glue on mine

You'll want to wipe the port down with solvent before spraying it. This process is much easier to do before the thing is assembled.

BTW, does the sub hit the SPL's you wanted ..... :wink:

[Bent]

BTW, does the sub hit the SPL's you wanted .....

It's kind of surprising, but although it is much louder than the 130 watt PSB subsonic 6 (Century 2i, actually) it replaced, I expected that with the output power afforded by the ADA 1200, that there would be just an obscene amount of bass - and I'm not much of a bass-head, I just wanted it to have a WHOLE LOT of reserve power. Anyone who saw what I was up to as this project developed seemed quite sure that there was something wrong in my head, and that I'd be wrecking my house at the same time. What I was completely taken aback by was how this sub integrates so well with my existing speakers, I had heard from some that combining a big 15" sub with the 6.5" mid bass drivers of my Paradigm Mini-Monitors/and matching CC-350 centre channel, would only leave me with bloated fat sloppy bass that only a 16 year old in a dropped civic would appreciate (I did believe that a well designed sub, with a big driver and lots of power could be made to sound any way you wanted, but still there was that nagging doubt... A doubt that was quickly put to rest when setting it up.), so for anybody thinking that they can build too much sub, here's my counter-argument. THEY ARE WRONG!

I don't think pipe cement is designed to glue ABS to PVC. The flare is ABS, the port is PVC. I just used hot glue on mine

I used a cement that claimed compatibility with both ABS and PVC - I had concerns about joining the two materials with ceement, so I used a small piece of the port tube material cemented to one of the flare flutes, after it set up, I checked the joint for any form of reaction, such as melting of one or the other plastics, bubling at the glue joint, or the plastic becoming brittle. I notice nothing of the sort. I also checked it for bond strength, and it seems very solid.

You'll want to wipe the port down with solvent before spraying it. This process is much easier to do before the thing is assembled.

I intend to wipe it with a isopropyl wipe, (we have them available for cleaning/removing wax from insulated switching sticks), I'll then use some 6 mil poly (vapour barrier) to mask the wood on the front and I'll just block the rear with whatever I can find... I know doing this prior to assembly would have made it much easier, but I'm sure everybody knows how anxiety can affect good judgement... ops:

Instead of paint why don't you make a ring that will fit over the extension and cover the flare with grill cloth in the approriate colour or make a grill to cover the front,

I've waffled to and fro a lot about a grill on the driver and/or the port, but part of what struck me first about the AS-15 when I joined this forum and caught the link to the AS-15 construction pages was how imposing a 6 inch port with a massive flare looked, I absolutely have to keep that flare and port visible to everybody... :twisted: I am, however, considering one of these industrial type Parts Express grills for the driver, as I think they compliment the character I'm trying to convey in this project.

If you're talking about veneering, as in the pine will be covered by veneering, then fixing the knot tearout is simple... bondo is your friend. It's an unusual and lucky cabinet project that doesn't have a little bondo somewhere...

Jon, I didn't intend to veneer the front, but I do wish to bring the veneer on either side, as well as the top all the way to the front edge, so the tear-out that occured on the left side about the one-third the way down the driver's height will certainly need to be filled with something, I had thought about veneering the front too, but I'm guite sure that the laminated pine front will not be as dimensionaly stable as the MDF, so it will likely shift and make my veneer job look worse than I intended. Taz, I actually have a whole bunch of DevCon epoxy that I actually paid for, LOL. BUt I'm thinking I may try some wood coloured epoxy first.

One thing I did want to mention about this BP 1503 driver, is that it's basket dissipates heat... I can actually feel heat in the frame underneath the rubber trim ring after i've had it powered up and running for an hour or so, and not necessarilly at any sort of high volume level. Is this normal, or could there be something wrong with my driver indicating a potential failure? I know I can't replace it anymore, but if the coil needed re-winding, could that sort of thing ever be done?

[Dennis H]

Any kind of black filler will look fine in a pine knot.

[Bent]

Dennis, I never thought of that... Excellent. Intead of trying to hide the repair, I'll make it so obvious that it would had to have been natural, after all, it used to be a knot...
I could try to "re-build" the knot. Thanks a million. :T

[taz13]

mix graphite powder into 5 minute epoxy and use it as the filler. Sands reasonably easy and will shine quite nicely when you varnish the panel.

[JonMarsh]

It's kind of surprising, but although it is much louder than the 130 watt PSB subsonic 6 (Century 2i, actually) it replaced, I expected that with the output power afforded by the ADA 1200, that there would be just an obscene amount of bass - and I'm not much of a bass-head, I just wanted it to have a WHOLE LOT of reserve power. Anyone who saw what I was up to as this project developed seemed quite sure that there was something wrong in my head, and that I'd be wrecking my house at the same time. What I was completely taken aback by was how this sub integrates so well with my existing speakers, I had heard from some that combining a big 15" sub with the 6.5" mid bass drivers of my Paradigm Mini-Monitors/and matching CC-350 centre channel, would only leave me with bloated fat sloppy bass that only a 16 year old in a dropped civic would appreciate (I did believe that a well designed sub, with a big driver and lots of power could be made to sound any way you wanted, but still there was that nagging doubt... A doubt that was quickly put to rest when setting it up.), so for anybody thinking that they can build too much sub, here's my counter-argument. THEY ARE WRONG!



I used a cement that claimed compatibility with both ABS and PVC - I had concerns about joining the two materials with ceement, so I used a small piece of the port tube material cemented to one of the flare flutes, after it set up, I checked the joint for any form of reaction, such as melting of one or the other plastics, bubling at the glue joint, or the plastic becoming brittle. I notice nothing of the sort. I also checked it for bond strength, and it seems very solid.



I intend to wipe it with a isopropyl wipe, (we have them available for cleaning/removing wax from insulated switching sticks), I'll then use some 6 mil poly (vapour barrier) to mask the wood on the front and I'll just block the rear with whatever I can find... I know doing this prior to assembly would have made it much easier, but I'm sure everybody knows how anxiety can affect good judgement... ops:



I've waffled to and fro a lot about a grill on the driver and/or the port, but part of what struck me first about the AS-15 when I joined this forum and caught the link to the AS-15 construction pages was how imposing a 6 inch port with a massive flare looked, I absolutely have to keep that flare and port visible to everybody... :twisted: I am, however, considering one of these industrial type Parts Express grills for the driver, as I think they compliment the character I'm trying to convey in this project.



Jon, I didn't intend to veneer the front, but I do wish to bring the veneer on either side, as well as the top all the way to the front edge, so the tear-out that occured on the left side about the one-third the way down the driver's height will certainly need to be filled with something, I had thought about veneering the front too, but I'm guite sure that the laminated pine front will not be as dimensionaly stable as the MDF, so it will likely shift and make my veneer job look worse than I intended. Taz, I actually have a whole bunch of DevCon epoxy that I actually paid for, LOL. BUt I'm thinking I may try some wood coloured epoxy first.

One thing I did want to mention about this BP 1503 driver, is that it's basket dissipates heat... I can actually feel heat in the frame underneath the rubber trim ring after i've had it powered up and running for an hour or so, and not necessarilly at any sort of high volume level. Is this normal, or could there be something wrong with my driver indicating a potential failure? I know I can't replace it anymore, but if the coil needed re-winding, could that sort of thing ever be done?

Basket is aluminum, which conducts heat away from the motor. Think about it, it's gotta happen, with a hundred watts plus power dissipation into the driver. 'Spose you could always put a fan in the port to cool the interior, huh?

[Bent]

mix graphite powder into 5 minute epoxy and use it as the filler.

Taz, that's the second time I've seen you mention black graphite in this forum...

I have no idea where to get it, I can remember using graphite powder to lube up a sliding bar on a bench mounted press - but that was years ago in High School (Lord Selkirk Regional Comprhensive).

[Bent]

with a hundred watts plus power dissipation into the driver.

I'm kinda wondering about this now. I know what 100 watts feels like (I've unscrewed a few bulbs to turn them off...:hb ), but I'd like to get a clue what kind of power the driver is dissipating when at a "moderate" listening level. I'll devise a way to do some comparitive steady state measurements, this could take a while...

[taz13]

Taz, I actually have a whole bunch of DevCon epoxy that I actually paid for, LOL. BUt I'm thinking I may try some wood coloured epoxy first.

8O:rofl: :rofl: :rofl:
Graphite is on the way. When you mix it, use about the same amount as the hardener. Or even better experiment with some different amounts. For a different look pick up some glitter(metal flake) and add that to the mix for a real standout filler. You can also mix up small amount of glitter in urethane to give your finish some sparkle. But if you try this do experiment on some scrap to see if you like it first.