custom sub enclosure

gp4jesus

rallyshark wrote: »

I'll see what I can come up with tonight after work:) FWIW, the ports don't have to be straight, and you need at least 2-3" clearance I think.

Port clearance minimum: 105-110% port diameter. Also, ports displace cabinet volume!

mhmacw

ok rally, heres what i did. i went with 2-4 inch ports 7 5/8 long. i tuned to 39hz. i flipped to the hip **** channel on the radio and my coffee cup fell off the end table. so after some serious phone calling to the stanly steamer i finally got stuff nailed down and gave it a whirl. its mainly for rock and roll jazz and ht so the 25 hz loss i dont think will be that bad. i didnt glue the extentions on the ports so they can be changed at any time to a length any where between2.25 t0 15 inches. the nomenclature said tune it to 39 (-3db) but it wanted 3 4 inch ports 12.5 long in a 3.25 box. ill post some pics soon but remember it still needs paint and feet/grille. i need to figure out how much clearence it needs off the floor as it ports down to the floor and fires forward. talk again rally, thabnks ,dan

gp4jesus

rallyshark wrote: »

So THIS is the final size?? If so, then I need to recalculate with the different size. I was figuring with about a 4 cubic ft, but this will end up being just a little under 5 after you subtract for the woofer/bracing etc.
Also, what is your major use going to be. If you tune it to 40hz, then you're going to loose a lot of the lower bass. It's response is going to fall like a rock below 50hz! Granted, it will be louder and peak around 50hz, but I don't know that it's worth the trade off.

Go for the lower cutoff. Otherwise it's likely to be a "boomer." That gi-normous amp should help you make up for the slightly reduced output

mhmacw

gp4jesus wrote: »

Port clearance minimum: 105-110% port diameter. Also, ports displace cabinet volume!

can the port be on the out side of the box?

mhmacw

the ports made a huge difference. it now seems under powered. which is what i expected the first time to be honest. i flattened the eq to 63 hz only. before i was introducing a bit of 160 hz to the mix. alos. i wonder about modification of my psw10. should i retune it to say 200 hz and tune the 15 to 25hz. is the prot clearence for in side the box. or outside?

rallyshark

Humor us and change you port length 11.5" , I think you will like the results:) If you don't like it, then change it back. The clearance is inside, and that applies to the port opening, but you don't want to put it too close to stuff on the outside either.
As far as the Polk sub goes, I wouldn't mess with it. It was designed to give the best all around sound with the given amp/speaker/enclosure. You wouldn't want to tune any sub enclosure to 200hz. That would be a disaster:o

mhmacw

ok on the no 200 hz thing. i guess ill have to find a different room for it. or leave it at the school. the cleartence issue on the outside is this: i want those cool spike feet things but am not sure if 1.5 inches clear under the port to the floor is enough? do think it will be ok? im off to cu the second port tubs now! yee haw!

mhmacw

ok i got them switched but the wife wants to go to lunch so ill get beack as far as the change. first impression is every change i make reduces the output(but tightens the responce) so i must be on the right track

rallyshark

Yep, sounds like you're getting there:) Output is no good if it's sounds like poo. Even with the 11.5" length ports, you should be able to get around a 120db when you get some power on it:D Play around with the placement as well. That alone is a good tuning tool. Also, if you can get it say 4-5" off the floor that should help. Let us know your findings when you get it finished!

mhmacw

well i put it on 5.5 inch risers(4 inch pvc). after the tuning phase is over it will get a shiny black paint job but until now im stuck with the mdf look lol. it sounds great! the punch is there and the boom is gone. if it stays like this and only gets more intense with the amp i think ive got a winner. i wonder though if the tone will change with the added power since it really will be a rather large increase. 5 fold i think... OH YEA! it seems to not be as bassy with the rap. not that the trial run was more than about 10 or 15 seconds as thats all of that i can stand. it sure rocks the house with r&r and the wii though.

rallyshark

It's always fun with projects like this. Yeah, you could just buy a HT sub that would likely do just as good, but where's the fun in that? Make sure and post some pics and final details when you get it all finished!

mhmacw

oh i certainly will. im not yet ready to post pics as the feet arent yet turned out and i havent put the finish on yet but its getting close. i do have another point to ponder and share hoping to get some more ideas. my thought is conicle oak legs and brass points but i dont want it to be 5 inches off the floor. other than hearing the air through the ports is there a performance requirement on the outside of the box for clearance? im not worried about hearing the port as the thing is so damned bassy it s not past the 2 on the amp amd im gluing stuff to the shelves. id like to be about 3inche(no more) off the floor. is this going to create any issues?thanks a bunch, dan

mhmacw

the amps are on their way! 2x 240 daytons. one for each coil! it just seemed....logical.

mhmacw

just a progress report. the amps havent arrived yet though im hopeful for tomorrow. the weather is still an issue it seems. the feet are installed and it is 4 inches off the ground. the feet made a considerable difference in sq. before it even geats mentioned im using the 35 watt amp that i had at first.

chiptouz

Amazing. I built my first sub when I was in college. I was bored with only 12 hrs that semester. It was a real fun project to do. How much cash do you think you saved over buying a new one?

mhmacw

ill know more in a few days when i compare it to an energy 10.3 side by side but i have 300 in it and put it next to a psw150 and you cant hear the 150. thats with a 35 watt amp 8 ohm. it sounds like your talking through a fan even with a teenie amp. the energy is 550$ and im sure youll be able to hear it but id say to get this performence it would take 800 to 1000 $ sub.

mhmacw

wow time flys! heres the finished product ...with out the finish lol if that makes sence. a friend in loves park is one hell of a painter and i thought maybe this summer after the theatre is done ill know better the color or finish and take it to him for the work.

rallyshark

Cool, let us know how it sounds with more power when you get to hook it up!

mhmacw

ok let me put it this way... i have 19 doors in my house and im on my 3rd box of squishy padded sticky things and im not even on the secon floor yet. other than wishing the house was built with screws instead of nails it sounds fantastic. at first i had the sub out signal split feeding both the right and left low level ins with a set of rca ics to the other amp. a little hard to controll. so i went to the right low level in on both amps with the 5 meter splitter and it tightend up like the knees of a 16 year old prom queen. and carry! damn. i put on the thump thump bang channel and went outside. whew! i think ill be able to hear it behind the barn now lol (thats what started this whole thing. i couldnt quite hear my stereo over the tractor behind the barn 250 yards from the house with the doors closed). the closest neighbors(1/2 mile away) called and asked if i wouldnt mind playing some 70s rock hahaha. NO ****! they are down wind so you know how that goes. any way. as good as this sounds i might have an energy 10.3 for sale. at least a psw150 and i have about 375 in the whole thing. i think ill start on some 1.2 tls next as soon as i can get close enough to a set to get measurements.

chiptouz

That is sooo cool. I am about due for a new project. How huge of a difference is a sealed enclosure vs a ported one. What are the the pros and cons of both.

mhmacw

chiptouz wrote: »

That is sooo cool. I am about due for a new project. How huge of a difference is a sealed enclosure vs a ported one. What are the the pros and cons of both.[/QUOT


the sealed will take less room. more power. and sacrafice low frequency efficiency. i preferred the ported box due to low frequency and ht applications. with my port system if i should need to change the tuning charachteristics i simply pull the woofer and put in a different lenghted section of pipe. youd have to build a nother box if it were sealed type.