ULTIMATE subwoofer challenge... can you do it?

[mikee12345]

24'' sub for music , wouldn't it be too slow ?

large woofers are not necessarily slow!

this myth wont die

http://www.adireaudio.com/tech_papers/woofer_speed.htm

however ,cone resonances may be a little low for comfort ,may need low crossover.\

people get the idea that large woofers are slow because-
-they produce low bass (slow bass)
-often people cant fit the proper enclosure size causing boomyness
-companys act stupid and sell high Q subs that are only of use in IBs ,but ppl try porting them..

 

[cowanrg]

do you have any pictures?

Hey David, I've been very interested for a while in using the 24" Precision Devices driver sealed for an AV/music sub, Can you tell me what volume you used in the enclosure and what you think of it's general accuracy and performance etc?.

I would imagine using two of them at full tilt would have the same effect as drinking a bottle of laxatives 😀

Stew.

 

[Stew320]

here is a picture of the driver in question, as you can see it's not a cheaply made driver. http://www.papl.co.uk/asps/ShowDetails.asp?id=17

They also do a 21" too

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

 

[DAVOhorn]

Thanks guys for the interest in the 24" subs.


FAST NOW LET ME SEE?????


YUP!!!!!!!!!!!!!!!!!!!!!

VERY!!!!!!!!!!!!!!!!

I have a digital camera a computer the software needed .

Only missing link is me the idiot who does not know how to use the technology.

I will post piccies when i can

The subs were built by a friend of mine.

he also built my 18" JBL sub.

Also 2 types of PD 21"
sealed box ala 24"
also 21" in a large vented enclosure with a 300w Magnum Amp as power amp and REL sub x over module.

He had his system in HiFi news within the last year.

Look For Wilson Grand Slam copies system in that mag.

The 24" are integrated into my large corner horn system so if they were not fast you really would know.


I will try and organise photos.
I am also building a large 3 way loudspeaker at this time which should be fun when it is finished.
This is a development of a previous project i built last year, but using different drive units in a larger cabinet.

regards David

 

[Bull]

reply

How about 2x 5 1/4 inch FOCAL Utopia 5WS subs
100w rms each,2 inch voice coil,4 inch magnet,long excursion.
Poly mineral cone???😀 😎

 

[mikee12345]

Fs 30.477 Hz

Qts 0.33
Qms 6.890
Vas 565.373 Litres
Qes 0.35
Mms 342.347 grams
Sd 2248.01 sq cm
Cms 79.333 uM/N

BL 32.357 T/m
that woofer has CONTROL

2200cm^2 area hahaahah
my jbl 15" is 880cm

1
$$$$$$$$$
can u measure THD %at all ?

 

[Stew320]

Hey David!

That very article was the one that made me aware of precision devices in the first place! wow that guy had some set-up in his room! the copy’s of the Grand Slamm's were amazing to say the least! using lead ingots to control panel resonance etc, not to mention all the other Wilson clones he had as his surrounds. Very impressive Has he done anymore projects since the article in HFN?

This type of driver makes sense to me for good accuracy and Spl's, I think more cone area and lower excursion is the way i'll go. The only thing that's an issue is the size of the box for an IB, but an Aperiodic lossy sealed enclosure is an option I might think about.

Can’t wait to see the photos,

Stew

 

[cowanrg]

ive heard that thing and its laughable! it sounds SO bad. its one of the worst subs we used to carry. its all plastic and very thing particle board, and couldnt even accurately reproduce midbass.

I do believe we can get good bass using decent 6 1/2 woofers in a car. Heres an exemple of what I do not trust. Sony claims that their SA-WD200 unit are able to :

reproduce 22 to 200hz,
plays 250watt,
with 2x 135mm woofs

sony sub

some might say its a damm good sub for its size, Ive not heard these things but Ive touched them once 😛. I just dont believe this sub can get under 40, Im not sure about sound4 either.

 

[mikee12345]

reproduce 22 to 200hz,

-10db points? 😛

''Second, Sony's two dome woofers move over a distance of 1-1/2 inches''GREAT just what i wanted a little woofer moving a LONG way! (extra harmonics for added impact) ;-)

''Frequency Response 26 - 200 Hz''

give me high area anyday!

 

[djbusyb]

the boxes are for real. try making your own like they have teh SS.. look over the plexi design. you'll be glad you did. you guys ever hear of lightning audio? I'm using a single 12" bolt subwoofer. it sounds just like a couple 15's this one guys has. the 20-30hz range is Falkin amazing. you WONT regret making a TL/ss box. I promise. or you can kick the crap outta my system... take your pick.. oh and the frequency we're battling with.. 20-30hz. you take your pick of which frequency cause the box is tuned at about 35 hz. whabam!

 

[BAM]

We're still trying to figure out what the technology in the box is, because there's definitely some trick there to get the kind of performance people are describing.

 

[Illusus]

"there's definitely some trick there"

Seriously folks...it's not much of a trick, it's just a back loaded horn. A fostex Fe103e driver will go down to 40hz...50hz with authority, in a small horn(eg buschhorn) this is a 4" full range driver with about 1mm one way xmax. It just takes a little hard work. Flex your brain, google, research, we won't just give the plans away to everything.

 

[djbusyb]

technology would be math and physics I suppose. read about pipe organs. and in phase gains.

 

[Bose(o)]

From some crappy 4" drivers from Wal-mart I smacked around my father's 15" actively powered Pioneer HT sub. Oh yeah, just one per box and nothing else. I'm keeping the design secret though...took me a lot of time and, I still don't fully understand why it works...same thing with TL's. I understand the maths, but the philosophy is bonkers!

 

[SkinnyBoy]

ok.. so if this is real.. lol someone design me a horn box thingo for my cheap 8 inch Venom subs.. 😀 ok? lol

or atleasy help me with it.. I wanna go to some Audio shop, and show them my $40 8inch subs.. and see if I can outperform (lower response and volume wise) some of their better systems.. 😀 I know the venoms are cheap... but their 100watt power handeling allows them to reach their fullest potential.. 😀 lol

I mean just look at them... lol someone help me.. 🙁 😛 lol

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.

 

[JOE DIRT®]

a 30 litre box would make those punch out the windows....the only thing would be to make sure your filter was setup properly.....go active with a sharp cutoff

 

[SkinnyBoy]

punch out the windows?
*SkinnyBoy checks for typos*
hmm... but I wanna see the guy in the car cry.. lol I guess I might see what these can do in about 45 litres ported in a car tomorrow.. 😀 except the umm.. inverter is abit underpowered.. lol 🙄

 

[JOE DIRT®]

45 litres and your going to get make them sound sloppy...been there LOL

I am talking per driver not total

 

[SkinnyBoy]

45 litres and your going to get make them sound sloppy...been there LOL

I am talking per driver not total

45 per driver too much??
been there???

wouldn't it somewhat depend on the drivers?

 

[Volenti]

What car do you have?

Make a folded bass horn and position it in the car so it uses the rest of the car as an extension of the horn throat.

I have a design sketched out for a pair of JL 8'' that I have lying around here but havn't got around to building it yet (too many other projects on the go , plus my car isn't suitable for that kind of horn loading)