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Bluto 6th November 2007 10:44 AM

Design Needed
 
So .... been all over the Web and can't find what I need.

Will definitely be going with an FR build soon. Planning a combo of MLTL's & something from Chang Family for fronts handling both HT and 2 channel Analog.

We have a real bad room and can't do anything other than one set-up that gets all in there . Current Subs must go.

Only 1 possible place for subs and thats in bookcase that is right against wall. Allocated space? 22 x 14 x 9. Thats it. Not a half inch more available. Only other alternative is infinite baffle cutting holes in floor and hanging into basement. Can't do it.

We don't like or need to hear 10Hz explosions on DVD. Had subs turned way down most of the time just to avoid such. All I'm after is something to fill in low's down to mid 30's that will integrate with FR's for music. I like Hammond B3 Organs, drums and I want to hear each string on 5 string bass guitar warble.

Anyone seen a plan with suggested driver or have an idea? I've owned 4 subs thus far in price range from $150 to $375 that sounded like trash to both of us. Must build. A proven design would really help. I'd like to keep my 250 watt JBL plate amp and send 125 to each side. That's likely a good deal more than we'll ever desire to use.

It's either this or one of the wives must go, can't get by without her income.

TIA

Bluto

bjorno 6th November 2007 10:13 PM

2 Attachment(s)
Quote:

...So .... been all over the Web and can't find what I need…
You must be kidding. :)

Quote:

…We have a real bad room and can't do anything other than one set-up that gets all in there…Allocated space? 22 x 14 x 9…
This is extreme. Listening rooms for music or HT have always place for properly placed speakers(subs) ensuring a good soundstage.

Quote:

…or have an idea?...
Here’s a suggestion that I believe may be sufficient, a sub meeting your space requirement if not the required height is 9”.

The 10” driver Scan Speak 23W/4557T00 or T02 cone permits the tuning of the Qtc using different stuffing densities without changing the resulting hear ability of the internal box transmission sound colours too much.

I wouldn’t shoot for a driver of less quality, 101 dB SPL at 32 Hz will sure rattle your book case. Look at the simulation: Picture 1(1)

b

1(1)

Don Bunce 6th November 2007 10:54 PM

Bluto,

Building a sealed box that will fit in that space will give you about 1 cu ft internal volume. put a Dayton TIT280C-4 10" Titanic MKIII driver in it,and you will be all set.

Part no 295-414 at www.partsexpress.com

Kinnja 6th November 2007 11:35 PM

Re: Design Needed
 
Quote:

Originally posted by Bluto
...Allocated space? 22 x 14 x 9. Thats it. Not a half inch more available...

Parts Express has a very low profile sub in their Project Showcase that might work for you. Its about 5" tall so it may fit under some furniture or some other unused space.

Look for "The Boogieman"

http://www.partsexpress.com/projects...e/projects.cfm

bjorno 7th November 2007 12:26 AM

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FYI: Dayton simulated using the same enclosure and the result overlaid using the posted picture 1(1) as template. T/S from PartsExpress ‘Dumax Report’.

b

1(1)

Bluto 7th November 2007 10:02 AM

Hi Guys -

Thanks for responses thus far.

Being a Novice at this I tried to give as much information as I've seen other members ask Plebes but perhaps I didn't give enough.

I'm picking up from these replies as well as others I've seen to similiar questions that there should be no big deal about building a subwoofer.

So ... a bit more info. The entire Net is filled with designs and theories on all kinds of speakers. The problem is you can't seem to find 2 guys that call the same type of enclosure the same thing. Some guy adds a piece of MDF to a design and suddenly it's got a whole new acronym. While these experts are doing this they are also constantly attempting to one up each other or arguing on the forums regards how this change makes this or that particular design of value or worthless because of TSP of given driver and a bunch of Physics values that were more than required to get Man on the Moon. Those of us that are my age when only a few smart Kids took Algebra let alone Geometry, Trigonometry or Calculus have no idea of what you speak nor can we begin to understand the myriads of charts we see. We know 2 things... 1) We've been burned by buying products from touted big brand names and 2) We believe those of you who speak this language we can't understand that tell us you have the answer.

I've read more than I can count in the last 6 months and still haven't a clue as to why any of the Guru's designs should work better than others or more so why they disagree with one another.

I've designed many different types of speakers on my own with knowledge I've gained in other principles in my Life and been surprised to see the very same ideas I came up with displayed by an 'expert' and accompanied with proof based in Math's. Would it surprise anyone that much of my designs come from my own experiences using hydraulic & mechanical principles? I do Organic Landscape and have built much of my own equipment to save me from the money changers in that Business. Hmmm...

I'm still left with My doubts for the above mentioned reasons so rather than waste the time and money on materials I throw out the questions I did hoping someone has worked with a similar situation and has a proven design to get me beyond my $365 JBL that sounds like garbage for less bucks. If I had the time and money I'd love to try my own thoughts which I believe would work just fine but not at the risk of blowing a decent driver because I'm an inch off here or there or my box would work fine but some TSP value in the driver I chose was just a bit off and had I chosen 'this' one instead ....

Can't do anything about the room, it simply stinks. 12' x 18' with a vaulted ceiling open to a Hall and Dining room . a Fireplace that diagonally cuts off near half a wall on one end, an 8' picture window on another and a poorly placed front door that gives me only 9"s on the remaining wall before it hits something when you open it. Add 65" into that equation for a Wide screen TV and some furniture and your possibilities become real limited. The basement rec room will eventually be an HT room as well and then I'll have some luxury in planning.

Were I seeing this as just building a sub box I wouldn't have even posted. No need.

This size limitation and the fact that it obviously must front fire and port and I don't want BOOM but I do want solid bass clarity is what had me hoping someone had dealt with a similar situation.

I wish my scanner was working as well as me knowing how to post my own drawings so I could share a couple of my own designs and see what you all think. Nothing bizarre and could be called several different names based upon the acronyms I mention above. I'd simply call them aperiodic TL's if such a title existed. I'd thought 8" drivers myself.

I apologize that I'm unable to do that and further that I don't understand the Math's. I'm sincerely trying to learn that but have yet to come upon any source that teaches it for those with my limited background. I won't buy any more books, those I've purchased thus far seem to assume you worked in a high end audio emporium for 10 years before you decided to build a box and put some drivers inside. Computer programs available as freeware are all set-up for XP and more memory than this machine has. I realize it makes it difficult for those of you trying to help newbee's when they can't understand these principles.

Bjorno - thanks for simulations. I can't find those particular plans on Kings site. I've been there before and will check again.

Kinnja - I'd looked at the 'Boogieman' long ago but didn't realize size was alterable until I went back tonight. Thanks for that, an idea I'll look more into.

Don - The highly acclaimed MKIII. I had thought of it and well reviewed considering it's price range. This was , in particular, one of the drivers I'd worried about my design possibly blowing up without me hearing it distorting due to driver placement. I had thought it too much for my size enclosure. Front firing sealed? Can't get any easier than that.

Thanks Guys -

Bluto

PeteMcK 8th November 2007 12:23 AM

"All I'm after is something to fill in low's down to mid 30's that will integrate with FR's for music."

Then perhaps you don't need a sub at all....as you've discovered, they're a PITA to integrate well into a system.

I think that what you need are a pair of good woofers, that will reach down to the low 30s, and up to ~ 300 to provide baffle step correction for your proposed FRs, and take the strain off them in the lows.

You can use your plate amp with a simple line level passive xover to drive the woofers separately.

But, lets not get the cart ahead of the horse, you won't need to decide what you need for the lows until AFTER you've built your FRs....

bjorno 8th November 2007 02:29 PM

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Quote:

…I can't find those particular plans on Kings site…
You cant find a plan with the SS 23W4557T00 at MJK; s site, its just a suggestion using the mentioned software as a template based on your given dimensions. I’ve listen to this driver in a 46L closed well-braced medium damped box built with 3/4” MDF and was impressed.

Looking at my previous simulations I found that the Dayton operated unintentionally in a larger volume that doesn’t fit the ‘space requirement’ and was giving an advantage over the ScanSpeak driver. This is now corrected and can be seen in the submitted pictures 1(2)-2(2).

Far Field f-3dB for the Scan Speak driver is 35 Hz and for the Dayton = 51 Hz using and if baffle correction is used the difference is slightly higher: 35 Hz versus 68 Hz.

The Dayton driver is really not suited for this application without compensation and don’t mach the ScanSpeak driver in terms of distortion, especially near x-max. Only when using a sub-amp preceding circuit like a LT the FR can be corrected to in my opinion a more suitable FR slope, but this will result in a power loss of 6.46:1 that is wasted.

b

1(2)

bjorno 8th November 2007 02:30 PM

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2(2)

Bjohannesen 8th November 2007 05:24 PM

Hi Bluto, could my HideAway help you, and just put the bookshelf on the top of it ?

http://www.coolcat.dk/bjoern/HideAway_SEAS.pdf

Hi from
Bjorn


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