Subwoofers for Beach Radio...

[m R g S r]

So i'm building a pretty silly beach radio. right now it consists of:

JL audio 300/4
JL audio 500/1
Pioneer AVIC d3
(2) speakers..Each containing: .8 cu ft. airspace, ported. 1 horn tweeter, 1 6.5" pyle sealed back midrange, 1 6.5" mach5audio mli65, dayton 2.5k 2 way crossover.
4 inputs on the back of the speakers, one directly to the mli65 midbass, one to the crossover (for the pyle midrange and the tweeter)

the main speakers will play down to 80hz or so with no problem.

Now I need some sub duty. Right now its up in the air. all i know is that i have 500 RMS and want the loudest sub setup possible...BUT...portability is a big issue. it can be a decent size, i will use 1/2" plywood to keep the weight down. (i'd rather have a box that has some resonance from the thinner wood than a broken back carrying a 200lb subwoofer onto the beach lol)

So i was thinking I would want a pro audio woofer, beacause of the high sensitivity and no need to feed it 3000watts to get loud. i am open to suggestions, i was thinking a 12" sub in 2 cu ft. boxe or so, maybe a single 15", or a pair of 10's (in two seperate boxes) someone on diyma suggested quad 8" dayton drivers.

type of music will be 99% house/dance/electronic. so the sub portion of the radio is pretty substantial.

one last thing, price. i'm not made of $$ (hence some of the driver choices, some stuff was left over, some was purchased cheap ) i would like to keep this thing down in cost. i was thinking about $150-200 max for drivers. wood i can buy at extra cost.

So, what is the best method of attack?

heres a few pics of the build thus far...


Pyle sealed back midrange, Dayton 2.5k 2 way crossover, constant directivity horn tweeter:

just laying the components on the MDF: mach5audio mli65 as midbass...

3/4" MDF front, the rest 1/2" birch plywood. going to be nice and light!

gotta love harbor freight for the cheap clamps and triangles!

clamped

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.

laying all the components in the holes..had the circle JIG on the wrong hole, sooo the hole i made with my router for flush mounting the midbass driver was a little too big...woops!!

 

[m R g S r]

handle for easy portability...i'll post the final weight once its loaded with crossover/components. but it's a lot lighter than the MDF enclosure i had previously.

 

[m R g S r]

Testing the first one..

An externally hosted image should be here but it was not working when we last tested it.

wiring the second

pair all loaded

 

[VictoriaGuy]

I hope this is your own private beach that you are talking about?
Far from neighbors?
Otherwise, earphones are really the least obnoxious way to enjoy YOUR tunes........
Picking up our blanket, picnic, and moving the family down to the other end of the beach......

 

[weltersys]

MDF on the beach will swell up like crazy unless coated with epoxy (or similar treatment) inside and out, negating the minimal cost advantages over decent plywood.

Tapped horn designs presently will give the maximum efficiency per driver and enclosed space, so are a big advantage if the system is to be driven using battery power which also needs to be lugged to the beach.

 

[m R g S r]

I hope this is your own private beach that you are talking about?
Far from neighbors?
Otherwise, earphones are really the least obnoxious way to enjoy YOUR tunes........
Picking up our blanket, picnic, and moving the family down to the other end of the beach......

the beach we go to is public, but if there is a family there i'd be surprised. actually, the last time we were there with the radio a family had their kids, we told them about the radio and let them know we were going to be playing loud music. they said the louder the better, and had their kids dancing around to the music mid afternoon.
i've had different variations of the radio, but this one i want to be the biggest and best. in the past when the amp went into protect mode, people would scream out awww what happened to the music?!
so it's not really an issue of me being selfish and ignoring the wishes of others. thanks for the concern thou! now back to the loud subwoofer part

 

[m R g S r]

MDF on the beach will swell up like crazy unless coated with epoxy (or similar treatment) inside and out, negating the minimal cost advantages over decent plywood.

Tapped horn designs presently will give the maximum efficiency per driver and enclosed space, so are a big advantage if the system is to be driven using battery power which also needs to be lugged to the beach.

my last radio was just painted 1/2" MDF, used it for 2 years with no problems so far. but it was heavyyy!

i know a horn will probably be the best bet, but a horn for a 12" sub is going to be pretty bulky. at the cost of a few db, a simple ported box could be a lot smaller, no? unless someone has a design for a horn that is compact.

now, i have two tang band 6.5" double folded horns in my living room. while i like them, they don't really have the output i'm looking for on this project. i really think i need more area from the drivers for this, hence the 12 or 15 i was thinking about.

 

[m R g S r]

these dayton 10" subs possibly? a pair of them would only run me $120....

Dayton Audio PA255-8 10" Pro Woofer

 

[m R g S r]

the system is to be driven using battery power which also needs to be lugged to the beach.

we used to use two batteries, one was 100lbs the other 50 or so. they would last a decent amount of time, but were a pain to carry.

i'm going to be building a small generator to be used in conjunction with a small battery, so power should not be a problem.

 

[chris661]

Those last drivers you linked to aren't subwoofer drivers. Not enough Xmax, Fs is too high...
But efficiency is good. Two of those would go very loud, though unlikely to go incredibly low. What's the target for extension?

 

[m R g S r]

That's the question, I don't know how low I need to go. I mentioned the type of music which will be played. Techno drums bass etc all require a strong subwoofer setup, but I'm not sure of the exact frequency they need to play to. I'm guessing 40hz but not really sure. I'm open to suggestions!

 

[Cokewithlime]

Personally I would forget the idea of a traditional "sub" and think about just belting out some clean loud bass. You are not going to hear or feel much of anything below 60Hz (20 ft away) unless you have a concert size speaker array and amps to power them. Most bass gut level "punch" is in the range of 60 to 80Hz and drum hits around 300Hz.

I would suggest using one or two Eminence Neo 12" Guitar Speakers, or Eminence Deltalite Neo
both fairly light weight with the Neo magnets and the first one I linked to is very efficient at 101db 1W/!m

 

[chris661]

I'd avoid guitar speakers completely.

The average SPL @1w is increased dramatically by the traditional peak ~4kHz.
Xmax is also next to nothing. Not suitable for this application at all.
Eminence sells other speakers with Neo magnets that'd be worth a look... Such as the one you linked to.

Speaker Detail | Eminence Speaker
A couple of half-decent 10"s will do what's needed.

Chris

PS - a 60Hz lower limit would be about right. If you want to go lower, much larger speakers are needed to get decent output.

 

[Cokewithlime]

Chris - it doesn't take much xmax to get very loud @ 60Hz and the OP mentioned in the beginning of the thread that he was planning on using a XO @ 2.5kHz to cover the top end (ie the typical 4K peak of guitar speakers would be almost inaudible)

I do think that the Eminence Deltalite Neo 10 or 12s are a overall better choice however, depends like it always does - on budget

 

[m R g S r]

no no the 100-2000000000 (or whatever ) frequency range is covered by the main speakers. i need something to go up to 100-150 range max.

I was just messing around with the HP filter on my amp while going through a bunch of different tracks on my ipod. the music sounds DRAMATICALLY different when the HP is set at 70 as opposed to 45. So i'm going to say that 45hz is a necessary bottom end for the sub. if that's all the driver responds to then thats fine, it will naturally roll off, correct?

 

[m R g S r]

Here a 12" peavey LF driver. 50hz bottom end..

Peavey Pro 12 Low Frequency 12" Speaker Driver

Would something like that work well? price is right...

and this dayton 12 goes down to 44, with decent sensitivity as well..

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=295-032

^the dayton in a 1.35 cu. ft. box has an f3 of 62.1hz...so the box would need to be a little bigger than that

 

[m R g S r]

here they are painted...and grills installed

An externally hosted image should be here but it was not working when we last tested it.

 

[Cokewithlime]

As I said previously, cabinets with the Eminence Deltalite Neo drivers will be a lot lighter to lug around and also give you the LF coverage that you are looking for.

The Preavy driver you indicated is OK but way heavy, look at the Neo version much lighter - but it's your back.....

You said you where looking for something to use in an open space at the beach - don't compare what you are hearing inside your house because it is and will be completely different outside in open air.

Don't waste your money and amplifier power on trying to get much below 60Hz because you will never achieve that for more that a few feet near the speaker in a outside open space, unless you go to multiple 12 inch or a large 15 inch driver in a transmission line or folded horn type enclosure with lots of wattage driving it.

If you don't believe me then do yourself a little reality check - if you have a sub at home take it out into the middle of your backyard and crank it up then go stand 20 ft away - sounds pretty wimpy outside dosen't it........

 

[m R g S r]

okay i know i lose room gain but for the kind of music that i want do you think that a HP of 60hz will be enough? i don't... from what i heard (i was not standing far away from the speaker, i was close to it listening to the change in sound as i slowly lowered the HP filter) i was much happier with the way the songs sounded with the HP set at 45-50 even at low volume.

anyway, i'm not looking to discredit you at all, i just don't want to go out and spend all the $ then not be happy with the way it came out knowing i could have had it play a little lower.

thanks for all the help thus far, i appreciate it!

 

[Cokewithlime]

okay i know i lose room gain but for the kind of music that i want do you think that a HP of 60hz will be enough? i don't... from what i heard (i was not standing far away from the speaker, i was close to it listening to the change in sound as i slowly lowered the HP filter) i was much happier with the way the songs sounded with the HP set at 45-50 even at low volume.

Do the same test outside and put the speaker 20ft away from you (typical of a beach setting) and make your decisions that way.