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Multi-Way Conventional loudspeakers with crossovers

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Old 30th October 2012, 10:13 PM   #501
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Thanks Cal.

TBH it MUST be easier to build up the number of cells you intend to use and then fix them together - as opposed to make the cells up, fix them together and then cut them flush all the while making the outer cells walls chamfered etc etc?

So what are the ramifications of the way the guy builds his horns? ie, cells starting from a flat plane, longest cells at the centre, shortest at the edge and odd wall thicknesses to get mouth sizes equal?
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Old 30th October 2012, 11:13 PM   #502
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We are hoping that you will buy a set and tell us!
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Old 31st October 2012, 12:52 AM   #503
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Default multicell horn construction

Pano,if you do decide to experiment with a different gasket and honing the transition would you please take as many measurements as possible? I am still very much interested in cloning the 1005 and have even been looking on ebay for a reasonably priced specimen that I can measure myself and later resell. You have posted some great photos here and in other threads and I think I could come close to the original by scaling the pictures. Close is not good enough for a project this involved.
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Old 31st October 2012, 02:40 AM   #504
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Will do. I can measure the horn dimensions too, if you need that.
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Old 31st October 2012, 08:55 AM   #505
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Quote:
Originally Posted by Pano View Post
We are hoping that you will buy a set and tell us!
Oh that I had £360 to burn. Thats probably all they'll give me for my car .

The guy seemed amenable to altering the throats so I might be able to get a pair with throats as per Cal's pic.

What differences would different length cells bring? Its kind of starts as a sectoral horn (vanes right up to a flat opening) and ends up multicellular. The outermost cells must be tuned to a different frequency....i guess? What he says about the outer wall length sorting it all out can't be right as the lobe emanating from the cell should be from the centre but it would be skewed the way the cells are now - maybe?
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Last edited by JRKO; 31st October 2012 at 09:02 AM.
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Old 31st October 2012, 04:59 PM   #506
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Quote:
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Ok he's come back with a bit more info - "yes the cells are slightly shorter on the outside banks but the throats make up the differance by being longer on the outside edges"

Does anyone out there speak 'multicellular' fluently? Pano, how are the start of the throats arranged in your horns? Cal maybe you can shed some light?

I doesn't seem 'right' to me

Well, I view a multi-cell as a tightly packed cluster [array] of single horns with one or more grouped to focus on a particular area/distance. From this we see that the cells won't necessarily all be the same design/shape and why there can be 10 dB [or more] difference between one 'cluster' and another in a large multi-cell since the core cluster will be focused long/wide while the lower L_C_R clusters will focus the area in between it and the stage/screen while the upper L_C_R will cover the balcony/cheap seats, all of which will increasingly collapse with decreasing frequency as each cluster, then horn, loses pattern control.

Their acoustical path-length should all be the same since it’s what sets the horn’s Fp [1/4 WL cut-off].

The answer then as to how to use them at home is the same as was done in stereo cinema and generally the best way to do a ‘shouty’ ~full-range driver, which is essentially what the large multi-cells are designed to mimic on a grand scale, i.e. point the left channel directly at or slightly above and/or beside the far right seating area and vice versa depending on how ‘hot’ its HF is; preferably located vertically either above or below seated ear height to focus/maximize the diffuse sound field to the left, right and behind the LP, rather than in front of, due to early reflections.

Since each cell is basically a tweeter horn, more is always better in a HIFI/HT app since at some point our hearing system overloads and internally sums them to a single point source plus the larger the horn, the lower, more focused its directivity [pattern] control, minimizing room interaction in front of the LP.

GM

PS: a bit of ‘eye candy’, Jensen’s relatively diminutive [32] cell [basically a divided up 805 IIRC]:
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Old 31st October 2012, 05:51 PM   #507
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Thanks for the added info GM! You are clearly very fluent in multicellular horns!! So cells being different from each other is not a bad thing.

So in theory the 15 cell mouth is okay, despite looking a bit funky

What GM said also confirms Pano's preference for more cells
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Old 31st October 2012, 06:43 PM   #508
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Cool pic. Does look like four 805s bolted together, side by side.
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Old 1st November 2012, 02:43 PM   #509
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ok - so I may be able to use 'some' of the insurance money from the car crash for a pair of drivers. As I have my Emkens and a set of Eminence Beta 15's I thought I'd go for the HF driver first.

Looking at the FaitalPRO HF144 details, it gives 2 'maximum power above...' figures. The first is at 0.9Khz of 160w and the second is at the lower figure 0.65khz of 80w (or half again for AES power figures). The recommended lowest crossover freq. is 900hz.

Can I take it from these figures that I 'could' cross over at 650hz, albeit not playing at concert levels? (80w/40wAES) Just wondering for playing about with crossovers etc

Crossing over above the main vocal range 1.5khz-2khz has the benefit of one driver dealing with that important 'band'. But dropping the crossover to 650hz-900hz lets me get more sound thru the horn....
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Old 1st November 2012, 09:06 PM   #510
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From what Bill found in his big compression driver test, at domestic levels you won't run into trouble within the pass band. But all the CDs he tested started to distort badly far below their maximum rated power.

As for crossing low, I've found that depends very much on the horn. At horn cut-off, distortion rises sharply and response falls rapidly. You should cross at least an octave above that. I'm sure that there are some 1" drivers that won't do well at 650Hz, even on a big horn, but the HF144 should not have any trouble on a suitable horn. Can't be sure without seeing measurements, but I doubt you'll have any trouble.

Bottom line. With a decent 1.4" or 2" driver, the horn will be the roadblock to crossing low.
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