Feedback on my intial design please (1 Viewer)

[Doug Montgomery]

O.k fellow DIYer's

After much posting and reading (as much as I can on 19200 dialup here in Hawaii)...I have decided to make a Sonotube sub with four Stryke AV15 MKII (thanks John Janowitz). I choose them cause of price and there simulated responses vs other drivers. I considered the Dayton Titanic MKII (only available in 12' though), but the cone excursion was pretty bad at lower freq.

Specs are as follows (wish I could attach files)

 Box Properties
 --Description--
 Name: SiloSub Quad-15 Ver 1
 Type: Vented Box
 Shape: Cylinder
 Dimensions: 32" High x 36" Wide
 --Box Parameters--
 Vb = 11.4 cu.ft
 V(total) = 15.05 cu.ft
 Fb = 17 Hz
 QL = 6.703
 F3 = 16.43 Hz
 Fill = normal
 --Vents--
 No. of Vents = 1
 Vent shape = round
 Vent ends = two flared
 Dv = 8 in
 Lv = 34.2 in

You'll notice I tuned the cylinder a little low (17 hz), but I found it helps shift the GD, VV and CD lower.

 Driver Properties
 --Description--
 Name: Stryke AV15 MKII
 Type: Standard one-way driver
 Company: Stryke Audio
 Piston: Aluminum cone.
 Suspension: Santoprene surround.
 Frame: 12-spoke cast basket.
 Voice Coil: 2-inch diameter.
 --Configuration--
 No. of Drivers = 4
 Mounting = Compound (isobaric)
 Wiring = Series-Parallel
 Drivers sum coherently = Yes
 --Mechanical Parameters--
 Fs = 22.39 Hz
 Qms = 5.293
 Vas = 140.1 liters [140.1]
 Cms = 0.143 mm/N [0.0358]
 Mms = 353 g [1412]
 Rms = 9.391 kg/s [37.56]
 Xmax = 23 mm
 Xmech = 30 mm
 P-Dia = 325.2 mm [459.9]
 Sd = 830 sq.cm [1660]
 P-Vd = 1.91 liters [3.82]
 --Electrical Parameters--
 Qes = 0.517
 Re = 2.95 ohms [2.95]
 Le = 3.5 mH [3.5]
 Z = 4 ohms [4]
 BL = 16.84 Tm [33.67]
 Pe = 500 watts [2000]
 --Electromech. Parameters--
 Qts = 0.471
 no = 0.293 % [0.293]
 1-W SPL = 88.5 dB [88.5]
 2.83-V SPL = 91.15 dB [91.15]

The Isobaric design really seems to help me keep the size down and it should make the drivers respond very quickly. Size is imporrtant, as if I were to use only 1 or two drivers, the tube would have to be hughe for the same response. (WAF :0 )

Amplifier is a ADCOM GFA555. Question, any difference in driving the four speakers in bridge mode vs runnin two drivers off one channel and the other two off the other channel?

Any suggestions or comments welcomed

Thanks,

Doug

 

[GrahamT]

Hey Doug, you must be FugTheBose. I was helping you at polk. I notice you are still using 8" flares, did you find any? THe specs look good but that port is too long. You want about 6" of clearance for the port entrance. I may be wrong but that port is about 34" long and the box is 32". I will also echo what others have said which is that this plan seams overkill and overly complex. Good luck with the project and do as much research as you can before you begin the project.

 

[Doug Montgomery]

LOL...How did you guess?

No, haven't even looked for the flared ports. I read where someone used 8" PVC. Do I NEED to use flared?...Couldn't I just use straight 8" PVC? You say 6 inches of clearance..are there guidelines?..I haven't found any yet on ports. Was also looking at using elbows in the boz to bend the port.

You say seems like overkill?..Can I ask why?

I have to do a Isobaric design, for the size issue. I want fast, responsive sound and great dynamics. I just don;t think I could get that with one driver (not to mention the size issue again).

Four drivers and a Sonotube and some MDF or Marine Grade plywood...still around $1000 in parts (give or take 20 %)

It's small, loud and looks very responsive..Yes?

Thanks bud..appreciate your input

Doug

 

[Jason_Me]

I don't know what your definition of small is, but in my view a 36" diameter tube is HUGE.

A Tumult with a pair of Stryke 18" PRs will give you all the output and extension you need in a much smaller box (think 25" cube).

 

[Allen Ross]

I have to do a Isobaric design, for the size issue. I want fast, responsive sound and great dynamics. I just don;t think I could get that with one driver (not to mention the size issue again).

'
i don't think you will get what you want with it ported that low, the fast response doesn't really happen that low, anything really below 25 IMO is a rumble explosion. If you are looking for speed i would look at 4 sealed with a BFD. Granted you won't get that low but you will get one hell of a tight sub.

As for the ports with an 8" i think 4" should be enough. at least thats what i remember when i built mine with dual 4" flared.

At least thats what i understand. i could be wrong and i have a lot.

 

[Doug Montgomery]

Jason_Me,

I appreciate your response..it got me looking into a PR design. I've never done that.

I took your statement and tweaked it with 3 PR-18-2500 PR's and the Tulmult in a 25" cube and Nominal filling. WOW...it "looks" great.

What say ye?

 

[Frank Carter]

I use a straight 8" port for each of my AV15's, I used 8" concrete tube forms from Home Depot.

I don't see any reason why you're design wouldn't sound spectacular. Although if you are using 4 drivers, you could do them sealed and use a linkwitz transform for the bottom end. Even with the LT you be able to get devastating output if you have enough power.

 

[Doug Montgomery]

Thanks..I appreciate every post..I know it takes time to repond.

I am a mod and many another types of forums.

 

[Doug Montgomery]

Using the Tulult with the VC's wired in series to get a 4ohm load...I see it can handle 800 watts PER coil (1600 watts total)...would my ADCOM GFA555 rated at 850 into 4 ohms bridged mono be able to push this thing effectively your think?

Also, with a 22 inch cube..how much bracing would be needed in the box? Can you get away with no bracing if you use double layer MDF or Marine Grade Plywood?

Thanks in advance

Doug

 

[GrahamT]

I say overly complicated because think of the construction difficulties for vented double isobaric sonosub. Even a tiny air leak or miscalculation will throw everything off. From reading your posts it seems that a sealed tumult would fit the bill and be easy to construct. Just my 2 cents.

 

[Jason_Me]

Also, with a 22 inch cube..how much bracing would be needed in the box? Can you get away with no bracing if you use double layer MDF or Marine Grade Plywood?

With a woofer of this caliber you want the box to be as massively overbuilt as possible. Bracing is a must.

 

[Doug Montgomery]

Thanks guys..always good to get feedback before spending $1000