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Multi-Way Conventional loudspeakers with crossovers

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Old 15th November 2006, 02:07 AM   #1
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Default It feels good to be back!

Woo hoo!

After a long break from DIY audio in favor of the more lucrative field of car audio sub enclosure building (sufficiently pleased with my 871s towers), I have decided that it's that time in every young man's life to do the thing. In my case, that thing is attempting to replicate my favorite speaker to date: The Definitive BP7001SC. It's their 2nd to highest end dipole design with their typical built in subwoofer. However, I have no desire to incorporate a sub into the tower as when I auditioned the speakers some time ago, I just turned the gain all the way down anyway. Now, it's time. First off, the things that I need 100% help on:

Drivers:

What sort of cones would be suitable for this speaker? I happen to have four HiVi D6Gs laying around from a previous project that I'd like to use. Unfortunately, they are absolutely hideous, and don't go well with any decor. Is there something that I should look for in the t/s that should give me a clue as to whether or not it will be a good candidate? I've also had bounds of luck with the Dayton 6.5" classic woofer, and buying for or even 8 of them would be cheaper than buying four more HiVi's.


Cabinet:

I'm fully aware as to what a dipole is, however, I'm unsure as to how to design one. Could I use two regular bass reflex enclosures opposed to eachother within the same cabinet, or would that just be counter productive? This is the part I need the most help with.


Arrangement:

Hamlet once said, "To D'Appolito, or not to D'Appolito, that is the question." Would a MTM for this design be superior to a TMM, or even a TM, or would it not be noticeable in my case?

Again, any help would be greatly appreciated. I expect this project to take at least until my birthday (finishing included, turn 18 on 2/11), if I can start over thanksgiving break. Glad to be back on the site!

-Dave
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Old 15th November 2006, 11:51 AM   #2
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Bump.
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Old 15th November 2006, 12:40 PM   #3
SY is offline SY  United States
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Re your last question, a properly done MTM will tend to have a narrower vertical dispersion than an MT or TM. That will definitely sound different; whether or not you like that sound (I do) is a matter of personal preference. I don't know what the Definitive is, but if it's got the sound you like, configure it the same way.
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Old 15th November 2006, 02:07 PM   #4
Rudolf is offline Rudolf  Germany
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Default Re: It feels good to be back!

Quote:
Originally posted by lemans23
I'm fully aware as to what a dipole is, however, I'm unsure as to how to design one.
The Definitive BP7001SC is advertised as a Bipole, not a Dipole.
Just a typo??

Rudolf
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Old 15th November 2006, 03:01 PM   #5
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Quote:
Originally posted by Rudolf


The Definitive BP7001SC is advertised as a Bipole, not a Dipole.
Just a typo??

Rudolf
No they are indeed a bipole design, they don't do anything dipole.

I've got a pair of the huge BPX surrounds and they're well good for the money I paid. I'm sure the larger floorstanders are equally as impressive.
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Old 15th November 2006, 07:51 PM   #6
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Quote:
Originally posted by lemans23
Bump.

LOL @ bump

You expected a response?

You might get more entertaining discussion
on the car audio forum
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Old 15th November 2006, 09:11 PM   #7
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Default Re: Re: It feels good to be back!

Quote:
Originally posted by Rudolf


The Definitive BP7001SC is advertised as a Bipole, not a Dipole.
Just a typo??

Rudolf

Pardon my typing, yes indeed.
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Old 15th November 2006, 09:13 PM   #8
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Quote:
Originally posted by thylantyr



LOL @ bump

You expected a response?

You might get more entertaining discussion
on the car audio forum
Entertaining, yes, but you know caraudio.com. I need real answers for this
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Old 16th November 2006, 02:37 AM   #9
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And it appears those real answers aren't flowing too well
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Old 16th November 2006, 04:37 AM   #10
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Okay, I said "F it" to the D6G's for a few reasons:

1. They're hideous
2. They're incredibly expensive to have to buy ANOTHER four
3. They're hideous

Now, I'm looking at these drivers and I made a design using both:

http://www.partsexpress.com/pe/pshow...75-070&scqty=4

http://www.partsexpress.com/pe/pshow...95-305&scqty=8

The drivers are cheap, sound good, and they fit the criteria for this endeavor: to replicate the sound of the speakers for a fraction of the cost.

It doesn't tell you much, but here's the design I made up. Circles are full diameter. The rolloff is decent with the design as sealed, but when I tune it to 50hz with a round port, the extension is lower, but the rolloff is like a cliff. I WOULD be worried, but my subwoofer should be stretching and waking up to do its job right around 50-60hz anyway. Okay, enough talk, onto the pics:

Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.

I want them to be black anyway, so here's what I was wanting it to look like in the end:

Click the image to open in full size.

Here's some rough dimensions:

Click the image to open in full size.

Click the image to open in full size.


What I still need help with the most is the size of each chamber. As it stands right now, each side is around 1 cubic foot for each set of mids and tweets. I do not plan to put the tweeter in its own chamber like I have done before because it would separate the mids and would give each a different amount of Vb. Anyway, help me out!

-Dave
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