new top, plan, critics and advices

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   Hello, i´m working in a project of a small new top.

it should working from (250or350 hz) to up,

It will count with 2x6.5'' 6g40nd from beyma and 2x1' 2200ti-nd from selenium

It´s only the project, the measures are not nery accurated in this momment, but take a look at the picture and say what you people think about it.

regards :-)

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ndreams Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 30 June 2006 Location: Portugal Status: Offline Points: 78	Post Options Post Reply Quote ndreams Report Post Thanks(0) Quote Reply Topic: new top, plan, critics and advices Posted: 01 November 2009 at 8:52pm
	Hello, i´m working in a project of a small new top. it should working from (250or350 hz) to up, It will count with 2x6.5'' 6g40nd from beyma and 2x1' 2200ti-nd from selenium It´s only the project, the measures are not nery accurated in this momment, but take a look at the picture and say what you people think about it. regards :-)
	Music & Audio the biggest addict of our soul. NN

ceharden Members Profile Send Private Message Find Members Posts Add to Buddy List The 10,000 Points Club Joined: 05 June 2005 Location: Southampton Status: Offline Points: 11776	Post Options Post Reply Quote ceharden Report Post Thanks(0) Quote Reply Posted: 01 November 2009 at 9:21pm
	The horizontal dispersion of the 6.5" midrange and the 1" HF will be very different.

james folkes Members Profile Send Private Message Find Members Posts Add to Buddy List Old Croc Joined: 08 January 2005 Location: United Kingdom Status: Offline Points: 3064	Post Options Post Reply Quote james folkes Report Post Thanks(0) Quote Reply Posted: 01 November 2009 at 9:29pm
	whilst shimmying this over to the new projects forum, a more fitting home where it will not drop off the front page for a while, i shall offer the following thoughts. you appear to be designing a very compact line array cab... two hf units and two horn loaded 6.5" will go very loud down to about 3-400-ish Hz on that size of horn, then you'll get bugger all underneath it. i would suspect that comb filtering artefacts in the horizontal would be a severe problem from having drivers side by side too... i think for this kind of idea you will need a single 6.5" on a wider dispersion horn and then some other driver/s handling the low mid in either a horn, bandpass horn, tapped horn, bandpass etc. configuration. that low mid section will have to be very potent to justify the rest of the enclosure... have a look at other people's solutions, like rog's new void arcline 12, the martin w8lm, russian forum user black cat's diy line array, or any other number of boxes that use trick methods to get bucketloads of 80-400 Hz from confined spaces. james.
	mardy hippy.

james folkes Members Profile Send Private Message Find Members Posts Add to Buddy List Old Croc Joined: 08 January 2005 Location: United Kingdom Status: Offline Points: 3064	Post Options Post Reply Quote james folkes Report Post Thanks(0) Quote Reply Posted: 01 November 2009 at 9:34pm
	re-reading that i think i kind of went off on a tangent... i second what chris says about the dispersion however, and re-iterate my point about the comb filtering. how do you plan to implement it? ground stacked in multiples? over what other boxes? james.
	mardy hippy.

ndreams Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 30 June 2006 Location: Portugal Status: Offline Points: 78	Post Options Post Reply Quote ndreams Report Post Thanks(0) Quote Reply Posted: 01 November 2009 at 9:42pm
	thank you, ceharden In the format of the box, yes, it´s true, but I´ve doubled the angle on high freq because on this horn seems to be too direct (litle dispersion) up of 5khz, I hope with this keep a good disp on high, amoung 60º horizontal, and a reasonable disp, even on 90º, i hope, or i´m completly wrong ? thank you
	Music & Audio the biggest addict of our soul. NN

ndreams Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 30 June 2006 Location: Portugal Status: Offline Points: 78	Post Options Post Reply Quote ndreams Report Post Thanks(0) Quote Reply Posted: 01 November 2009 at 9:54pm
	hello James Folkes and thanks for your advices, I´m will stacking 4 units per side, for low/mid, It will be double 15' box hybrid (horn and band pass type) for each top, suspended in the air also. about one 6.5''? that´s an ideia, but then I will stay with too much high's, maybe put only one driver, on the box, thanks
	Music & Audio the biggest addict of our soul. NN

Centauri Members Profile Send Private Message Find Members Posts Add to Buddy List Old Croc Joined: 29 November 2004 Location: Newcastle Aus Status: Offline Points: 1792	Post Options Post Reply Quote Centauri Report Post Thanks(0) Quote Reply Posted: 02 November 2009 at 4:15am
	As mentioned, there will be interference between the two 6.5" drivers, and this will effectively narrow the dispersion in exactly the same way a line array narrows the vertical dispersion by stacking vertically. A more serious issue will be the distance between the left 6.5" and the HF horn - this will result in cancellations around the crossover frequency. The 6.5's will need to be tucked in as close to the HF as possible, either by vertically stacking the 6.5's (like the Martin boxes) or by putting the HF horn between them (which will still cause narrowing dispersion unless you reduce the overall width).

staiper Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 26 February 2004 Location: Croatia Status: Offline Points: 545	Post Options Post Reply Quote staiper Report Post Thanks(0) Quote Reply Posted: 02 November 2009 at 1:38pm
	Here is one of mine .. close in external dimensions (OK.. a bit larger - based around 8" mid units and two HF units on " waveguide") Designed as compact line array module. Simple thing.

ndreams Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 30 June 2006 Location: Portugal Status: Offline Points: 78	Post Options Post Reply Quote ndreams Report Post Thanks(0) Quote Reply Posted: 03 November 2009 at 12:47am
	thanks for your advices I have some beyma 6g40nd on stock, so I must use that ones, but one beyma for two drivers I´ll have too much high freq, So I quick redraw a scatch: But just maybe I don´t have enough spl on mids, comparing if I put them on a horn. the box have 4 ports, for freq. res. of 100hz. take a look:
	Music & Audio the biggest addict of our soul. NN

Centauri Members Profile Send Private Message Find Members Posts Add to Buddy List Old Croc Joined: 29 November 2004 Location: Newcastle Aus Status: Offline Points: 1792	Post Options Post Reply Quote Centauri Report Post Thanks(0) Quote Reply Posted: 03 November 2009 at 1:40am
	Whilst that configuration will improve the situation at the crossover point, the additional width between the midranges will decrease the horizontal dispersion further. Some boxes with this arrangement utilise an extra crossover where only one of the midrange drivers cover the upper frequencies whilst both drivers operate at lower frequencies. However, this also means that at the HF crossover point you have only one front-loaded midrange trying to keep up with two more efficient HF drivers... Arranging the midrange drivers in a V as in Staiper's design above can address the dispersion issue, but you still have the low efficiency of front loaded speakers, and the midrange cones also introduce a large discontinuity to the HF wave guide. Covering the midrange drivers with plates having vertical slots (like the JBL Vertec) can reduce this discontinuity and reduce the acoustic width somewhat, but you are still left with low midrange efficiency. Looking at the plan view of Staiper's box above, if the midrange drivers are moved back level with the HF driver, the midrange drivers can then get horn throats which can exit as vertical slots into the main flare either side of the HF wave shaping element - this can give excellent results (have been playing with this configuration myself) but makes for a VERY complex build.

ndreams Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 30 June 2006 Location: Portugal Status: Offline Points: 78	Post Options Post Reply Quote ndreams Report Post Thanks(0) Quote Reply Posted: 03 November 2009 at 2:26am
	Thak you centauri for your awesome advice, I think I can understand you, I will do a scacth for it. mean while, for the same dimensions ( lenght and height) as this last box, a crazy, simply, not very certain if it works, for lows, to 350 more and less. it uses a 15'' from beyma 15mw nd, in the paper seems not to be a great speaker but believe almost the boxes i try it, sounds better than 15p1000nd, but don´t have so much power, but is a very light speaker, 3,6Kg. take a look:
	Music & Audio the biggest addict of our soul. NN

ndreams Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 30 June 2006 Location: Portugal Status: Offline Points: 78	Post Options Post Reply Quote ndreams Report Post Thanks(0) Quote Reply Posted: 03 November 2009 at 5:06am
	Here another draw, what you think about this one, maybe yes maybe not, that´s the question Whether 'tis waves in the ear to suffer The dbs and watts of outrageous sound, Or to take pressure against a wall of wood, And by opposing end them? To loud: to crazy lolol :-D take a look ;-)
	Music & Audio the biggest addict of our soul. NN