A padawan needs guidance here

Madmike2 · 27th April 2005, 03:55 AM

HI again. I just had another idea. Feel free to rip this apart. Keep in mind that i will have active EQ and 6 channels of amplification. Ok what i propose is and correct anything i say wrong i can go back and read all the data again till i understand it exquisitly. here is a cheesy picture to clarify my written description.

http://i4.photobucket.com/albums/y12...ike2/Basic.jpg

i want to take Surgical packing foam, it comes in a grayish black colour and flat sheets of 5/8's thick and sandwich it. Front baffle will be 1/2 inch white pine and the rear support and baffle will be 1 inch mdf that i have. each panel will be 4 x 8 inch woofers wired series paralell to a single channel. In the middle of these sitting side by side will be a 4 inch mid and cd5 fountek ribbon tweeter either wired together to one channel with a simple 12 db crossover since there will be an active x-over removing 400 Hz and lower. Or i can run the tweet on a channel the mid on a channel and the 4 x 8 array on the 100 watt channel with the Dbx doing crossover duty. The front baffle will be in the range of 90 % decoupled from rear as i will use 2.5 inch black mushroom bolts and polyurethane donuts on the back side with wingnuts to cinch the speakers to the front baffle. Almost all the transmission of energy that does make it to the back will be through the poly as the medical foam is CDC certified for vibration absorbtion.

So from what i understood part of the problem with an open baffle IS the baffle. Will taking its effects out or shrinking its footprint in the reproduction picture help ?
Just so you know i just backspaced a whole freaking book back to here, just to ask it in a way i SHOULD have asked it. WIll this design affect or lesson the baffle effect in this design assuming that this array would be valid? Or will it just destroy the point of the open baffle.

I will be reading SL page while i wait for the flaming to begin :-)

Michael

Madmike2 · 27th April 2005, 02:34 PM

Ill take the lack of response as a good thing. Are you all trying to figure out if it would actually make a difference?

In that picture the red fill between the black and the blue is supposed to be the foam sandwich.

Cal Weldon · 27th April 2005, 04:29 PM

Can't answer anything about the OB but you might wish to vertically align the mid and tweeter.

Cal

Madmike2 · 27th April 2005, 07:36 PM

Really ? i didnt think that would make a diff with such a gigantic baffle area.

Madmike2 · 27th April 2005, 07:38 PM

Darn, putting those vertical adds 7 inches in height. Thats not a good thing.

adason · 27th April 2005, 09:07 PM

how about this arrangement /use any amount of woofers, i just did not wanted to redraw whole pic/
that should reduce the hight considerably

Madmike2 · 27th April 2005, 10:46 PM

I see . Stick to the line pattern. So in essence i coult MtM a line in the middle of the woofers ? Or as in your picture edit i could off set them as if it was a ribbon line along side.

mike.e · 28th April 2005, 04:26 AM

well in the above situation there will be some source shifting continually due to different horizontal positions,how bad,I duno.

Id go vertical if possible. Why 4 x 8"s?Wont 2 do?

Bear in mind that the 8"s if reproducing the same frequency range will comb filter when the wavelength approaches the driver to driver spacing[midrange]

planet10 · 30th April 2005, 05:06 AM

What drivers?

Nothing wrong with the design. MJKs Focal TLs worked better with side-by-side driver mounting -- showing that conventional wisdom always has to be considered with a grain of salt.

The wider the baffle the lower the bass.... as drawn you will need lots of EQ to get any bass, and 4 8s probably will run out of excursion... making the baffle wider means you won't have to work them as hard.

dave

Madmike2 · 30th April 2005, 05:52 AM

Hi Dave, i just talked to you in the other forum

Man i am a little tipsy right now on a brilliant california red.

The current dilemma floating in my head purculating its math around is a series of SIX 6.5 inch Vifa's LCY tweeter 6 inches north of center on a 19.5 in wide baffle 54 inches tall.

I have EQ and multi amps covered to play with i am just trying to imagine the sound. Its a lot of money for me. I am the cheapest guy around unless it involves something that entertains me

27th April 2005, 03:55 AM	#1
Madmike2 diyAudio Member Join Date: Apr 2005 Location: Toronto	A padawan needs guidance here HI again. I just had another idea. Feel free to rip this apart. Keep in mind that i will have active EQ and 6 channels of amplification. Ok what i propose is and correct anything i say wrong i can go back and read all the data again till i understand it exquisitly. here is a cheesy picture to clarify my written description. http://i4.photobucket.com/albums/y12...ike2/Basic.jpg i want to take Surgical packing foam, it comes in a grayish black colour and flat sheets of 5/8's thick and sandwich it. Front baffle will be 1/2 inch white pine and the rear support and baffle will be 1 inch mdf that i have. each panel will be 4 x 8 inch woofers wired series paralell to a single channel. In the middle of these sitting side by side will be a 4 inch mid and cd5 fountek ribbon tweeter either wired together to one channel with a simple 12 db crossover since there will be an active x-over removing 400 Hz and lower. Or i can run the tweet on a channel the mid on a channel and the 4 x 8 array on the 100 watt channel with the Dbx doing crossover duty. The front baffle will be in the range of 90 % decoupled from rear as i will use 2.5 inch black mushroom bolts and polyurethane donuts on the back side with wingnuts to cinch the speakers to the front baffle. Almost all the transmission of energy that does make it to the back will be through the poly as the medical foam is CDC certified for vibration absorbtion. So from what i understood part of the problem with an open baffle IS the baffle. Will taking its effects out or shrinking its footprint in the reproduction picture help ? Just so you know i just backspaced a whole freaking book back to here, just to ask it in a way i SHOULD have asked it. WIll this design affect or lesson the baffle effect in this design assuming that this array would be valid? Or will it just destroy the point of the open baffle. I will be reading SL page while i wait for the flaming to begin :-) Michael

27th April 2005, 04:29 PM	#3
Cal Weldon Speakerholic diyAudio Moderator Join Date: Jan 2004 Location: British Columbia	Can't answer anything about the OB but you might wish to vertically align the mid and tweeter. Cal __________________ Next stop: Margaritaville Some of Cal's stuff \| Cal Weldon Consulting

30th April 2005, 05:06 AM	#9
planet10 frugal-phile(tm) diyAudio Moderator Join Date: Oct 2001 Location: Victoria, BC, NA, Sol III Blog Entries: 4	What drivers? Nothing wrong with the design. MJKs Focal TLs worked better with side-by-side driver mounting -- showing that conventional wisdom always has to be considered with a grain of salt. The wider the baffle the lower the bass.... as drawn you will need lots of EQ to get any bass, and 4 8s probably will run out of excursion... making the baffle wider means you won't have to work them as hard. dave __________________ community sites t-linespeakers.org, frugal-horn.com ........ commercial site planet10-HiFi p10-hifi forum here at diyA

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27th April 2005, 02:34 PM	#2
Madmike2 diyAudio Member Join Date: Apr 2005 Location: Toronto	Ill take the lack of response as a good thing. Are you all trying to figure out if it would actually make a difference? In that picture the red fill between the black and the blue is supposed to be the foam sandwich.

27th April 2005, 07:36 PM	#4
Madmike2 diyAudio Member Join Date: Apr 2005 Location: Toronto	Really ? i didnt think that would make a diff with such a gigantic baffle area.

27th April 2005, 07:38 PM	#5
Madmike2 diyAudio Member Join Date: Apr 2005 Location: Toronto	Darn, putting those vertical adds 7 inches in height. Thats not a good thing.

27th April 2005, 10:46 PM	#7
Madmike2 diyAudio Member Join Date: Apr 2005 Location: Toronto	I see . Stick to the line pattern. So in essence i coult MtM a line in the middle of the woofers ? Or as in your picture edit i could off set them as if it was a ribbon line along side.

28th April 2005, 04:26 AM	#8
mike.e diyAudio Member Join Date: Sep 2004 Location: NZ	well in the above situation there will be some source shifting continually due to different horizontal positions,how bad,I duno. Id go vertical if possible. Why 4 x 8"s?Wont 2 do? Bear in mind that the 8"s if reproducing the same frequency range will comb filter when the wavelength approaches the driver to driver spacing[midrange]

30th April 2005, 05:52 AM	#10
Madmike2 diyAudio Member Join Date: Apr 2005 Location: Toronto	Hi Dave, i just talked to you in the other forum Man i am a little tipsy right now on a brilliant california red. The current dilemma floating in my head purculating its math around is a series of SIX 6.5 inch Vifa's LCY tweeter 6 inches north of center on a 19.5 in wide baffle 54 inches tall. I have EQ and multi amps covered to play with i am just trying to imagine the sound. Its a lot of money for me. I am the cheapest guy around unless it involves something that entertains me

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