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Old 25th August 2008, 03:48 AM   #2261
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Has anyone considered some of the Rythmik drivers for TH use? I'm presently planning to build a couple of smaller THs for PA use. The major issue with THs that I've encountered in Hornresp is related to diaphram displacement. Given the large displacement peaks above the horn cutoff, most drivers hit xmax way before they run into their power limits. In trying to squeeze out the most performance, I came across the following driver from Rythmik:

http://www.rythmikaudio.com/DS12driver.html

This driver has an xmax of roughly 35mm, (if I am reading their specs correctly). The BL is a bit on the low side, but overall, not bad for around 130 dB from a single 12" driver (roughly 350W).

This driver also has a servo sensing coil and Rythmik sells one custom servo controller amps. I wonder if that might be of use in helping to control displacement or for taming out some of those anomalies at the top of the TH's bandpass.
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Old 25th August 2008, 05:12 AM   #2262
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Quote:
Originally posted by craigwalsh
Has anyone considered some of the Rythmik drivers for TH use?

I'm presently planning to build a couple of smaller THs for PA use.

This driver has an xmax of roughly 35mm........

The BL is a bit on the low side, but overall, not bad for around 130 dB from a single 12" driver (roughly 350W).

I wonder if that might be of use in helping to control displacement or for taming out some of those anomalies at the top of the TH's bandpass.
Not me..........

Its specs doesn't seem all that conducive to a small PA app.

Xmax is a one way spec, so ~17.78 mm.

FWIW, the BL is too low for the rest of its specs, so none to be trusted IMO, which they shouldn't be for a horn design anyway.

Well, if I'm understanding what it does, then it doesn't much matter what the speaker's response looks like or how accurate its specs as long as it doesn't run out of gain BW for the signal input. If true, then you can shrink it for a small PA app since you won't need to worry about how smooth/flat its response.

GM
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Old 25th August 2008, 01:40 PM   #2263
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Shiva-X is on sale now, 135USD, 54mm Xmax p-p, SPL 84.5db...but maybe Qts 0.47 is on the high side fore TH ???

Roughly, how would sensitivity be fore this driver in a TH ???

I am asking because I need to decide whether my future system should consist of an 18" woofer with no sub needed, or if I should use a 15" with better lower mids, but with the need of subs, which could be TH...but will they be good fore music only ???
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Old 25th August 2008, 02:41 PM   #2264
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Will what be good for music?

In the meantime, how about a ~1426 L built-in Tempest-X 'house wrecker'?

GM
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File Type: gif tempest-x 10-61.67 hz conic th (+3 mh).gif (18.5 KB, 969 views)
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Old 25th August 2008, 05:00 PM   #2265
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Your right, I suppose I will do a straight 3way and "bass Eq" the pro woofer with Fc around 30hz
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Old 26th August 2008, 04:09 PM   #2266
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Quote:
Originally posted by GM


Not me..........

Its specs doesn't seem all that conducive to a small PA app.

Xmax is a one way spec, so ~17.78 mm.

FWIW, the BL is too low for the rest of its specs, so none to be trusted IMO, which they shouldn't be for a horn design anyway.

Well, if I'm understanding what it does, then it doesn't much matter what the speaker's response looks like or how accurate its specs as long as it doesn't run out of gain BW for the signal input. If true, then you can shrink it for a small PA app since you won't need to worry about how smooth/flat its response.

GM
Thanks for clarifying Xmax. Hornresp's help file states that it displays the one-way maximum (1/2 wave) displacement. I get it now.

Rythmik lists a couple of other 12" drivers with higher BL. It would seem those might be useful for TH, no?

So, some issues come to mine. In the effort to identify high output for say around 30 Hz low cut, it seems as though the limiting factor is Xmax. Is this correct? If so, what 12" driver has the highest Xmax that would be useful for a TH alignment? Second, how do TH alignments deal with bass transients (like kick drum) compared to standard bass horns or vented enclosures? In other words, does the TH require that the signal fed to them have roughly symetric 1/2 waves for each cycle? Finally, I don't see why servo sensing couldn't be used to counteract the displacement peaks that limit the BW of the TH.

Thanks all! This has been very informative.
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Old 26th August 2008, 05:29 PM   #2267
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You're welcome!

Hmm, just so we're on the same 'page', the DS12's specs indicate a higher BL than what's published and its specs are fine for a TH (see attached 2 pi design based on a calc'd BL), just not for meeting your app unless you make multiple smaller ones and stack them, which of course still eats up trunk/whatever space and increases driver cost, though the trade-off is greater dynamic headroom due to the extra drivers.

Yes, all else being equal, Xmax (~10 % distortion) up to Xmech (bottoming out) is a design's limiting output factor, but an acoustically larger one can match it with less Xmax, ergo less power input, so it depends.

Not familiar with all the various drivers available and just because it has a high Xmax doesn't necessarily mean it can handle the high compression loading at high excursions without excessive distortion, so better IMO to use a proper prosound horn driver in a PA app and if it won't play loud enough, make more of them unless some other type such as a car audio 'sub' driver has a known reliability in a TH PA app.

Pretty much the same as a BLH and 'blows the doors off' a vented alignment as TD shows in his TH white paper: http://www.danleysoundlabs.com/pdf/danley_tapped.pdf

GM
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File Type: gif rthymik ds12 14.14-103.17 hz conic th (+2 mh).gif (13.4 KB, 839 views)
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Old 27th August 2008, 09:52 PM   #2268
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After building a tapped horn, I built a pair of bandpass subs using the exact same woofer, in an enclosure half the size. Are you curious what the subjective difference is between the two?

Then read this:

Tapped Horn for Dummies
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Old 28th August 2008, 09:09 PM   #2269
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Default A couple of quick questions.

I have been modeling a wide range of drivers using hornresp and I have noted that a lot of drivers seem to benefit greatly in the area of smoothness of response by making the L1 distance significantly larger than L3. Has anyone actually implemented something like that? If so how did you lay it out and how did it perform?

Also I am considering using 1/2" OSB for my initial trials due to the 1/3 lower cost versus plywood or particle board. How might such construction color my results?
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Old 28th August 2008, 09:35 PM   #2270
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Hmm, seems like it should be the other way around in which case Tom Danley has. See his DTS-20 patent application someone posted here awhile back.

I imagine it will buzz if not heavy/inert enough and it will lose some of its gain, especially down low, if it can 'breathe' at higher SPL due to the walls flexing.

GM
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