SiloSub Design Help

Dr. Spec

That post by John was later refuted. Check the entire thread.

No, you cannot use both vents and PRs (I supposed you could try, but I think it would be a disaster).

A small enclosure will lack the volumetric efficiency of a larger enclosure and will roll-off quicker, lacking output at Fb. It would likely require EQ to achieve a flat response down to the resonance frequency of the enclosure.

Doug Montgomery

Thanks Dr. Spec...hope I'm not too much of a PIA

Doug Montgomery

Using Bassbox Pro..would this Krell MRS type system be considered Standard or Standard Push-Pull in the mechanical configuration section??

Ceruleance

im pretty sure push-pull. Good luck building that monster, seems like the only way they get decent response out of it is by driving the hell out of it, 2.6 kW....

Doug Montgomery

Oh No thank you...not looking to build that..was just curious as to its configuration. I'm assuming they are out of phase..so when one pushes out, the other is pushing in..to canel out harmonics or non-linearity. But was wondering how that effects SPL, effiency and power needed.

2.6 kW..Damn....reminds me of 'Back to the Future'

Dr. Spec

That Krell is a joke. For what - $20+ grand? GAFB. I could spend $2500 and beat it senseless.

Doug Montgomery

O.k.."Hi"..its your local PIA..LOL

I'm trying to get things ready for my project and need some more advice. i understand that someone stated you should not decide solely on plots from a program..but they should be used for a "estimate" I believe. For instance I use CircuitMaker to design circuits before I breadboard..just to make sure it will work..not to mention I can add things like temperature and see how it "should" react.

O.k...After reading the "Black Hole" thread..I am thinking of making a Wholoper. Was thinking of a prism with 6 sides and 4 drivers with their VC and the drivers wired so as to have a 4 ohm load and 3 to 4 3" double flared vents. Based off ALL of your great input and my reading..these seem like the best choices for drivers.

Brahma 15 ($439 ea)
Tulmult 15 ($
Dayton Titanic MK II 12 ($128 ea)
Stryke AV12 or AV 15 ($140/$165 ea)
Tempest 15 ($150 each)

Money is no object (to a point..don't forget WAF). I would like to keep it below $1000 or so. Based off the cost up there....would it be better to use four 12" or 15"?

Also, would 4 12" MKII have a higher SPL and faster response than 2 15" drivers?

I saw this statementr on another site...could someone put this in a plainer english?:

"The amount of low bass a system can deliver is directly proportional to the amount of air it can move, i.e. it's proportional to the driver's Vd spec. Although the obvious solution to low bass is to simply use a larger driver, this approach has some drawbacks:

The large box is constrained due to the dimensions of the driver, i.e. there has to be at least one face of the box large enough to fit the driver.

As a driver's diameter increases, its useful off-axis response decreases. For example, the average 12" driver has a conservatively rated upper limit of ~550 Hz while the average 5" driver has a conservatively rated upper limit of ~1300 Hz. Note that this limitation is imposed by the physics, and is always there regardless of the driver's on-axis frequency response.

The next obvious solution is to use multiple smaller drivers. Typically, these are use in vertical arrays. Doing so provides the same wide horizontal dispersion as a single small driver (albeit at the expense of vertical dispersion (which is often a good thing since it eliminated floor and ceiling bounce). On the other hand, arrays of subwoofers typically are put on adjacent sides of a box rather than aligned vertically on a tall box. Array systems may be sealed or ported.
The only caveat for designing arrays is that too many people base their estimates of how much bass they can achieve by simply multiplying the number of drivers by the individual drivers' area (Sd). This is deceptive since bass is dependent on Vd, not Sd. An array of drivers works as if it is a single driver with an Sd value equal to the sum of all the drivers in the array, but a Vd value calculated from the Xmax value of a single driver."

Thanks

Ceruleance

can you link me to that thread please?

Doug Montgomery

By your command!

http://ldsg.snippets.org/boxes.php3#SEALED

Ceruleance

thanks! that was much more informative and all inclusive than some of the other sites! ELF design and tapered design were particularly interesting (ala sunfire and B&W)

goingganzo

actuley i never dertermanded of it was the amp or the driver. i have the amp in a different room. and that is 110 with the rs meter

at normal vewing levels i dont even come close to my limits. i can also push past 120 with playing brass monkey.

Doug Montgomery

huh?

Dr. Spec

The upper frequency limit of a woofer is indeed size related. But you will be crossing over at say 80 Hz, and even an 18" Maelstrom can play that no problem.

Sd is the effective surface area of the driver. xMax is the maximum linear excursion the driver is capable of. Vd is the volume it displaces with one full piston stroke.

And speaking of stroking - avoid pie-in-the-sky complex designs and stick to reality when building your first DIY sub. If you want to talk sub design theory and various configurations ad nauseum, the DIY sub forum is the place to do it.

http://www.diysubwoofers.org/talkshop/

My last recommendation and post to this thread will be an AV-15 II based sono-tube subwoofer with a downward firing woofer, baseplate, and at least three 3" flared vents, tuned to 22-23 Hz and powered by around 500 watts continuous into 4 ohms. Not hard to build and will perform extremely well even in large rooms.

Doug Montgomery

Dr Spec,

After reading your post, I am getting the impression that you are upset with me?

I appologize if this was the wrong place to talk about this. I was under the impression I could. I was in no way not heading everyone's word in here, although this is my first DIY sub, I also wanted something that looked well inthe livingroom and performed well also.

I was just trying to understand all the terminology and find out wht some things plotted differently than I expected them too. Bouncing ideas off of fellow forum members is what I have done in other forums and found it a nice way to get ideas.

I will refrain myself from posting such things in here again


Again..I appologize to anyone I have upset

jdhdiggs

I do not see doc as upset, he seems to not want you to overreach. Unless you have mad carpentry and wiring skills with all the proper tools, I would definately go with one woofer sonotube.

How big is your room BTW? A four woofer configuration in a non-IB setup sounds like either overkill or an underenclosed or huge subwoofer.

Also, for under $1K, you''ll have a hard time buying all the wood, bracing, wiring, screws, glue, speakers, PR or vents, amp, and eq in a 4 speaker setup.

In the end it's your decision but unless you have an enourmous room, a single 15" sonotube with the right driver should give you almost all the performance you could want. If not, build a second and co-locate. Two of the AV-15 and the sonotubes with good amp and vents for about $600-700 fully constructed.

Doug Montgomery

The room is approx 17X13, however the back has no corners..it opens to my kitchen and living room.

I like the SonoTube, but think the wife would NOT like it. Was looking at something like the SVS B4 Plus. Smaller cube with a low (18-20 Fb) and a pretty flat to 16 HZ response.

As I hope all can tell..I have beeen doing ALOT of reading and "testing" in BassBox Pro.

Thanks Again,

Doug

goingganzo

actuley around 1k for dual av15
165 per sub 175 with delevery
350 for amp samson s1000 500 per side
200 for svs bass box
ports 20 bucks
materals 100-150


this is my take if you want to buld a ported box you will need to spend 50-100 on clamps. pen state has good clamps prety cheap.lowes and hd will cut the pannels for you. they do a good job but can need to be trimed. also go dual 4 in flaired vs 3 3 in flaired and buy the flaired ends and buld them your self 5 bucks vs 23 for complete. also if you buld a big box buld horsonal and vertal brases it saves you money and weight.

Doug Montgomery

The $200 fot SVS Box...what is that? If I am building the box, do i need to order this from SVS?

Also, I already have a ADCOM GFA555 that outputs 850 bridged into 4 ohms

Thanks Again,

Doug

goingganzo

it has a ss filter gain and phase 0-180 or so the ss filter is so you dont over drive your sub below tune and the gane is for pro amps but you dont need that and the phase is for ajust phase. plate amps come with all this at least most and that is y you pay more for a plateamp.

Doug Montgomery

Thanks bud

Would you happen to have the particulars on the SVS B4 Plus?

I.E. its dimensions and if the four drivers are really a pair of isobarics in a push pull setup?

looking at the picture I jusdged its size, but could not get the specs they tought.

Doug

Ceruleance

doug, do a search for the B4 on hometheaterforum, or on this forum, you will find pictures that explain exactly how it is set up. Its basically a box within a box, there are the 2 outward firing drivers on either side, but then right behind each of them is another driver that is firing into the box, and the chamber that has the backs of those two drivers is open to the room and covered with grill cloth.