Once in a lifetime IB Subwoofer Blowout

Kevin Haskins · « **Reply #20 on:** 17 Jul 2007, 12:44 am »

Ok... the 15" is up on the web site. I'll put together a PDF with recommend box sizes and alignments along with simulations tomorrow.

I'll try to get the 12" up on the web site before I leave. The wife has called twice asking when I'm coming home though..... may need to put it off until tomorrow.

http://www.diycable.com/main/product_info.php?cPath=24_93&products_id=652

I don't know what that damn pink line is on top of the site. My web developer is working on it. Its nothing security related so don't panic.

Kevin Haskins · « **Reply #21 on:** 17 Jul 2007, 01:05 am »

Here is the web page for the 12" driver. The weight of these two drivers are almost the same. You wouldn't think that a 12" & 15" would come in so close but the motor is identical in the two models and its 90% of the mass.

http://www.diycable.com/main/product_info.php?cPath=24_93&products_id=653

Kevin Haskins · « **Reply #22 on:** 18 Jul 2007, 03:39 pm »

Either of these drivers make great Dipole units. The parameters work good and they have the displacement necessary for the application.

Just an FYI...

Kevin Haskins · « **Reply #23 on:** 18 Jul 2007, 06:16 pm »

If you have been checking shipping prices on things via our site it has been quoting high shipping prices. Sorry... my web developer was working with the shipping module in the database over the weekend and had it set up such that it was charging too much. Don't know exactly why but its fixed now.

ooheadsoo · « **Reply #24 on:** 18 Jul 2007, 06:27 pm »

For us diy dummies, what kind of baffle do we need and what kind of performance can we expect from 1 of these drivers in dipole?

Kevin Haskins · « **Reply #25 on:** 18 Jul 2007, 08:44 pm »

Quote from: ooheadsoo on 18 Jul 2007, 06:27 pm

For us diy dummies, what kind of baffle do we need and what kind of performance can we expect from 1 of these drivers in dipole?

Give me some time tonight and I'll put together some guidelines and simulations. I'd like to analyze power requirements, baffle size and driver excursion under standard SPL levels before I spit out an answer.

Voodoo Rufus · « **Reply #26 on:** 18 Jul 2007, 08:46 pm »

Hate to nag....what about dimensions?

Kevin Haskins · « **Reply #27 on:** 18 Jul 2007, 10:20 pm »

Quote from: Voodoo Rufus on 18 Jul 2007, 08:46 pm

Hate to nag....what about dimensions?

Hey... your not a nag. I had an old girlfriend that set the bar in that category.

Baskets are standard 12-spoke Venezuela. Same as used on many of the 12" & 15" cast basket subs on the market. PE uses it on the Titanic so mounting dimensions are the same.

Here is the 12"
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=295-404

Mounting depth is different. The 12" is about 7.5" and the 15" is about 8.25".

Here is the 15"
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=295-420

Kevin Haskins · « **Reply #28 on:** 19 Jul 2007, 08:01 pm »

I'm a little slow on the dipole drawings and updates. I have some orders to ship & bills to pay before I can get to it.

Another topic.... if you want more than three woofers and you go through the shopping cart the shipping calculator will not allow you to pick a shipping method. The reason? It thinks the order is a single package and the weight goes up over the UPS maximum shipping weight. I don't have any easy way of changing the shipping module to get around this at this time.

Just break it into orders of < 3 woofers. It will cost the same but then you will be able to check out with your >150lbs of woofers.

Sorry for the trouble.... won't cost you a penny extra but you will have to submit two or more orders.

TerryO · « **Reply #29 on:** 19 Jul 2007, 08:21 pm »

Mr. Haskins,
It would be interesting to see the sims of what a dipole would do. I wrote a good friend recently suggesting that a pair of these per side and a Hemp full-range might be a possibility.

Best Regards,
TerryO

Kevin Haskins · « **Reply #30 on:** 19 Jul 2007, 08:39 pm »

Quote from: TerryO on 19 Jul 2007, 08:21 pm

Mr. Haskins,
It would be interesting to see the sims of what a dipole would do. I wrote a good friend recently suggesting that a pair of these per side and a Hemp full-range might be a possibility.

Best Regards,
TerryO

I'm working on it....

Its not as simple as other boxes because LSPCad doesn't have a "dipole" simulation. Linkwitz has a good spreadsheet where you can input baffle size and get an output curve. You also need to look at excursion and output levels to see where you become displacement limited.

Long story short.... I'm working on it but got to pay some bills before they turn out my lights.

doug s. · « **Reply #31 on:** 19 Jul 2007, 08:46 pm »

hi kevin,

re: box size, for the 12", you recommend a 3cuft box w/a single port. would a 6cuft box w/dual ports be the ticket for two 12" drivers in a single box, or is it more complicated than that? (and, would i need a 14cuft box for two 15" drivers - yikes!)

thanks,

doug s.

Kevin Haskins · « **Reply #32 on:** 19 Jul 2007, 08:46 pm »

Oh... one more thing. Wiggins came up with a great concept (I think its his first good idea) for a compact dipole layout. It takes into account the rocking associated with large driver excursions. The drivers are mounted so that their rocking cancels and you get a wide effective baffle width. I'm working on that and just a simple H or W baffle layout with some projected HP passive filters so that you don't need active EQ to use these. All you would need is the baffle (you build), the drivers, the passive network (you build) and an appropriate amplifier.

Kevin Haskins · « **Reply #33 on:** 19 Jul 2007, 08:53 pm »

Quote from: doug s. on 19 Jul 2007, 08:46 pm

hi kevin,

re: box size, for the 12", you recommend a 3cuft box w/a single port. would a 6cuft box w/dual ports be the ticket for two 12" drivers in a single box, or is it more complicated than that? (and, would i need a 14cuft box for two 15" drivers - yikes!)

thanks,

doug s.

Yes and no... The box sizes are listed PER driver. These really are large box subwoofers when use in typical boxes. They are better suited to IB or dipole use due to the high Qts, lots of displacement. Our up and coming drivers (Shiva-X & Tempest-X) will fit better in more typical box sizes.

Box tuning isn't as simple adding an additional port when you double the volume. The relationship is not linear so you have to model the enclosure, with the number of ports & their size to get the correct tunning frequency.

What I recommend to people is rather than build one large enclosure with multiple drivers, but two completely different subs. As boxes get larger their panel sizes become problematic to damp. You start to need LOTS of bracing. Your better off having two subs in the room anyway. Two subs will give you a smoother in-room response than a single one (typically). Two subs will have smaller panels and footprints so you have fewer problems with enclosure resonances. Smaller enclosures act more like the modeled enclosure because those panels flex as you get larger. Smaller subs are easier to move and build.

Just my 0.02.... take it or leave it.

TerryO · « **Reply #34 on:** 19 Jul 2007, 09:10 pm »

Quote from: Kevin Haskins on 19 Jul 2007, 08:46 pm

Oh... one more thing. Wiggins came up with a great concept (I think its his first good idea) for a compact dipole layout. It takes into account the rocking associated with large driver excursions. The drivers are mounted so that their rocking cancels and you get a wide effective baffle width. I'm working on that and just a simple H or W baffle layout with some projected HP passive filters so that you don't need active EQ to use these. All you would need is the baffle (you build), the drivers, the passive network (you build) and an appropriate amplifier.

Actually, Mr. Wiggins has come up with a couple of good ideas, or three if you count RDO (or whatever he called it). The third one was actually an idea I came up with 20-25 years ago and mentioned on the old Bass List. Dan had the know-how and math skills to actually work out a model, which quite honestly, I wouldn't have been able to do. Now that, my friends, was probably "the ONLY" good idea that ol' TerryO ever had, and I'm grateful that Dan was able to develop it successfully.

Best Regards,
TerryO
BTW: I'm kidding of course, Dan actually has had more than a few good ideas.

Kevin Haskins · « **Reply #35 on:** 19 Jul 2007, 09:21 pm »

I was certainly being sarcastic. Dan's a freaking idea machine.

doug s. · « **Reply #36 on:** 19 Jul 2007, 09:24 pm »

thanks kevin. i would never do a sub system for audio w/o having two.

sounds like i should consider building four single box subs, & then stack them, if i want two drivers per side?

regards,

doug s.

Quote from: Kevin Haskins on 19 Jul 2007, 08:53 pm

Quote from: doug s. on 19 Jul 2007, 08:46 pm
hi kevin,

re: box size, for the 12", you recommend a 3cuft box w/a single port. would a 6cuft box w/dual ports be the ticket for two 12" drivers in a single box, or is it more complicated than that? (and, would i need a 14cuft box for two 15" drivers - yikes!)

thanks,

doug s.

Yes and no... The box sizes are listed PER driver. These really are large box subwoofers when use in typical boxes. They are better suited to IB or dipole use due to the high Qts, lots of displacement. Our up and coming drivers (Shiva-X & Tempest-X) will fit better in more typical box sizes.

Box tuning isn't as simple adding an additional port when you double the volume. The relationship is not linear so you have to model the enclosure, with the number of ports & their size to get the correct tunning frequency.

What I recommend to people is rather than build one large enclosure with multiple drivers, but two completely different subs. As boxes get larger their panel sizes become problematic to damp. You start to need LOTS of bracing. Your better off having two subs in the room anyway. Two subs will give you a smoother in-room response than a single one (typically). Two subs will have smaller panels and footprints so you have fewer problems with enclosure resonances. Smaller enclosures act more like the modeled enclosure because those panels flex as you get larger. Smaller subs are easier to move and build.

Just my 0.02.... take it or leave it.

Kevin Haskins · « **Reply #37 on:** 19 Jul 2007, 09:34 pm »

How big is your room Doug? What do you listen to?

doug s. · « **Reply #38 on:** 19 Jul 2007, 09:48 pm »

i don't know the exact dimnensions, but it's a pretty big space. i presently live in a studio apartment above a four car garage. ~20x40 or so. my present pair of vmps large subs do not energize the room, unless i *really* crank it, w/bass-heavy material.

my listening habits are all over the map. i like acoustic guitar, loud rock, jazz, latin, african, caribbean, classical, folk, electronic, etc....

doug s.

Quote from: Kevin Haskins on 19 Jul 2007, 09:34 pm

How big is your room Doug? What do you listen to?

Kevin Haskins · « **Reply #39 on:** 19 Jul 2007, 10:22 pm »

Ok... four is more than I'd use but if you want overkill we can go there.

If you wait, I'll have the production woofers in 8-12 weeks. Its roughly Shiva & Tempest parameters. They are going to be in the $150-$175 range so you miss out on the killer deal but its not a deal if it doesn't fit your situation. I try to tell my wife that and she just doesn't get it, but I digress.

If you wait, you could either go with four Shiva-Xs (same driver as we have on special but the suspension compliance has a cms > .500mm/N and Qts drops) in 3 ft^3 ported boxes with an alignment that gives them a low frequency curve that matches a sealed box Qtc - 0.7 or so. That would give you lots of output (ported alignments) and a fairly musical setup.

A sealed setup with four Tempest-X would give about the same output but require larger sealed boxes. Maybe on the order of 4.5 ft^3.... I won't know exactly until I have production T/S parameters.

That's what I'd suggest. Either that or take advantage of the garage below you, buy four of the current 15"s on sale and build a killer IB. I'd suggest a SMS-1 for bass control and an appropriate amp.