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Simi's Official 12" subwoofer build.

No, no way to add any boost near the fs... unless this filter I'm getting strangely has some way to add boost, but I sure wouldn't imagine it would....

I have an EQ in the system, but the lowest register on it is 30hz.. but compared to what I have for bass now at lower volumes, anything is going to be a big inprovement.

I'm kinda leaning to more power, more effecient, and a little higher tuning as being better too... especially knowing how far I can twist knobs..
 
I like the LAB12 driver, but I'm biased because I know the guy that designed it.

Anyway, something to think about as far as bass boost is the enclosure size. It might be possible to build an optimum enclosure with a removable panel so that you could add mass inside the box (bricks, phone books, whatever). Left alone it would be flat as low as possible but with the right mass inserted it would raise the Fb a little but also raise the Q so that there is a bass hump just above Fb.

You could change from low, neutral bass to night club bass by putting the mass into it. I don't know that I'll have time to run numbers today though as we're having visitation for my father-in-law tonight and I'll be pretty busy. All things considered, I'd rather be designing speakers.
 
That's a cool idea about adding mass inside the box. Never thought about that. So if I get this adjustable filter, make a port with a slider on it, and make the slot big enough to fit bricks through, I'm going to have a hell of an adjustable sub.

I've pretty much talked myself into the LAB12. It's not that much more money, and It just reads and appears to be a lot better performing and built driver than the GR driver is. Not putting down the GR driver at all, but considering the speakers I'll be running these with, and what I have invested in my barziwaves, this is a drop in the bucket, so might as well go with the beefier driver.

I'm sure you'll have fun tonight Ray. You can build speakers any day, but family isn't always around...

You've been a huge help with this project and I greatly appreciate it. SO.. I'll be ordering parts today... the only real drag about this project is, it's going to be at least 3 weeks before I can start building the boxes. I'm leaving on a cruise next Friday, and got too much to do before then. And then, I sitll gotta clean up my garage so I can get to my saw, much less my bench tops..
 
PARTS ORDERED!!!!

I'm getting excited about this build..

I ended up going with the LAB-12 drivers. They just seem to be more in line with the drivers in my Barzilay cabs performance wise. Might as well keep on that track.

I'll be buying the plywood as soon as I get back from my cruise, so don't get too worried if you see nothing. I'll be back on this in about 3 weeks...

I got gold 5 way binding cups, and went with rubber feet. I can't do spikes on my hardwood, and not going to risk those sliding off metal pucks. I'm figuring with my mains sitting on top of these subs, that would be around 175 lbs sitting on the spikes..
 
Strictly speaking in terms of maximum output in that size of box, the Lab would be limited by xmax well before the GR, but to pass it by, the GR would have to exceed its rated power. More or less a wash, on paper. Efficiency is also nearly equal below 40Hz, and roll-off is equal. Just sayin'. I like the Lab :thmbsp:
 
Well.. there's always the option too of eventually buying the GR drivers too and putting them in the box and trying them out. Going by what I'm planning to build box wise, and with the crossover, and a few bricks if need be, I should be able to try just about anything I want in there.
 
The good news: Bass is probably the least critical as far as incorporating sub duties, compared to the hyper-critical mids and highs.

The bad news: Despite the forgiving nature of bass in general, overlap is probably the worst enemy, as you apprently already have woofers in action. You might find yourself tweaking far more than you might care to or desire. There are way too many variables for most anyone to predict the end result of this or most any sub project, when all is said and done from my personal experience.

My advice: Hedge your bets: Regardless of the claims so far, I recommend the most fail-safe method of all for excellent results from the start. Forget passive, as the results are far too limited for subs for the most part and the severe penalty it places on efficiency over and above the limits of the subwoofer all add up to a double deal-breaker.

I hope and presume that you have a dedicated amp for sub duty. If not, please reconsider. If so, all you need to enjoy the easiest, most wide ranging adjustability of all is to buy most any low cost car stereo active crossover that features the typical, variable turnover and level controls for lows and you're way, way ahead in the ease of essentially infinite adjustability instantly and on the fly. The results are surprising in the best way and incredibly satisfying, as the audio quality will usually surpass most anything you might otherwise expect. Yes, you'd need any old 12VDC wart, but that's the easiest, cheapest part of all to purchase, if you don't already have one...
 
I really think this FMOD box I got will be the ticket.. it is passive, but it's in line passive.. between the pre- and the amp... that way I'm only sending the lowest freqs to my amp and not wasting the rest of the power to be filtered out at the speaker. This box is the same as an active crossover, only it doesn't need power. Change a jumper or two, and you change your cross point. It has 16 pre defined crossover freqs... it also has an 18db slope, so it should play real nice in this situation.

If that doesn't work out how I like, I've got an active crossover I can put in place, but would rather not do that.

Yep... I got big PA amps to use too... I'm a bi- and tri amper all the way... I'm not a big fan of passive crossovers either..

Which brings me to a WHOLE nother idea I have in the back of my mind, but will only mess with it after I decide if I like the subs or not..

My Barziwaves I built I built with Zilch's modified Model 19 crossovers. I have everything wired so I just make a couple small changes, and I can remove them from the system, and actively bi-amp.. .which if I do like these subs (I better after dropping all this cash) then I may look at tri-amping this system. I think I would be MUCH happier with my barzi's bi and tri amped.
 
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Don't be afraid to use a pro audio crossover tuned by ear...always worked for me. Hook up only the subs to it and you'll still have full-range out your tops. My idea, never heard it elsewhere, works a treat as our Brit friends say. Hope all's well with you, Simi. Been awhile.
 
I was thinking about picking up another crossover for this, but that's more money, and a space in my cabinet I don't have. Once I get an amp in, I'm all sold outa real estate..

I figured for $40 I can try out this little black box.. if it doesn't work to my liking, then I'll go for a pro crossover. I have one I can put in there too and use it to tune everything, then decide what I need to do exactly.

OH, looks like I'm getting an Ashly FET-500 amp to run these on... should be plenty of power to keep up with my mains.
 
Hot damn... step one completed... I just got two beautiful woofers from Fed-Ex a few minutes ago... Some well built nice looking drivers for sure. They look like they should easily keep up with my Lambda's..
 
Hey Sim. I am running 4 subs now and the sound is extremly level anywhere in the room. If I had to do it all over again, I would build for boxes and use one amp. PE has a stand alone sub amp with all the adjustments on it, so you only need to run wires instead of pluging in all your plate amps. If you are running 4 boxes, the cost of the one amp is less than 4 plate amps. If you MUST use a plate amp, I highly recommend the BASH amps. They don't get hot and they are really clean sounding....JMFUMSF!
 
OK, you got the LAB12. Check the 3Pi (Wayne Parnham, Pi Speakers- I posted a link in other S/W thread) for box dimensions and port length using that driver.
Running two of these with Yamaha PC-2002 (250W per channel pro amp).
That X/O box thang does look good- have been using a Pyle PXLR2 car X/O with success, adjustable and cheap- although there is a hummm somewhere in the line: http://audioroundtable.com/forum/index.php?t=msg&th=1859
 
RayW said:
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=266-250

You can get them for a bunch of different frequencies. That's just an example.
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Hey Ray, have you actually used these FMOD devices to good effect or are you just offering up a possible solution? I have a similar application (more or less) and if these actually work, would be a very inexpensive solution to what I am trying to accomplish.

I'd be interested in hearing from others that have used these also. Low Pass, not High Pass.


RC
 
I'm waiting to get my FMOD box... Looks to be the same as these plugs, only it's in a box and has adjustable cross points... SO, I can at least let you know how that one works if no one chimes in about using the RCA plugs.
 
similost said:
I'm waiting to get my FMOD box... Looks to be the same as these plugs, only it's in a box and has adjustable cross points... SO, I can at least let you know how that one works if no one chimes in about using the RCA plugs.
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The PFMOD you decided to give a go looks interesting also Simi. I just don't need the high pass filtering for what I'm trying to accomplish. All I'm trying to do in this project is attempt to roll off the woofers around 50Hz. Actually, with a second order or 18db/octave, lower would be preferable but Harrison does not offer that option.

I would be very pleased if they do exactly as advertised but if not, hopefully they will work reasonably well as a temporary fix.

Looking forward to hearing your thoughts after you get up and rolling :yes:


RC
 
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I hope to start on miine the weekend of x-mas.. so hopefully I can let you know soon..

HHhmmm.. did I miss something? Does the Harrison also have a highpass filter on it too? I was thinking it was strictly low pass.
 
BTW... while this thread is back active again, Yesterday I was trying to figure out what size slot I would need to create in order to port these boxes.

I read, and re-read, then scratched my head a lot, and just couldn't figure out the math on how determine what size slot I need to use... is there someone here that would be able to tell me if I gave you all the measurements you'd need to figure it?

What I was thinking about doing, on the front, just create the front baffle shorter than I'd need to fill the complete space... so basically, the slot will be 14" tall on one end of the front baffle... I just couldn't figure out how wide I'd need it.. .as in, instead of cutting my board to 20" wide to fit the front of the box... cut it to like 19, or 18" or what ever..

Make sense?
 
I can simulate a slot size for you, but the way that you integrate it into the box will change the effective length (similar to how a flared end changes length). I guess what I'm saying is that it would be difficult the nail the length on the first try, which is true of any port, but slot ports are of course much more of a pain to alter.

IIRC, you will have quite a bit of wiggle room for what will sound fine with this combo, at least. Anyhoo, what's the latest internal volume calc you're working with? Am I reading correctly that you want to use the external box walls for 3/4 slot walls?
 
similost said:
I hope to start on miine the weekend of x-mas.. so hopefully I can let you know soon..

HHhmmm.. did I miss something? Does the Harrison also have a highpass filter on it too? I was thinking it was strictly low pass.
Click to expand...


I think I figured it out. I was under the assumption that there was just one of these devices available from Harrison. When I googled Harrison, I found the PFMOD 2W-1 which provides both high and low pass for a 2-way. You went with the PFMOD LP-1. Looks like that is just low pass.

RC
 
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