i wonder if something DIY could fill the gap..?
the tone of the RCF 905a is excellent but its a single 15 design..
anyways just having conversation lol
the tone of the RCF 905a is excellent but its a single 15 design..
anyways just having conversation lol
Frequency Response
30 Hz ÷ 120 Hz
Max SPL @ 1m
133 dB
https://twaudio.de/en/product/b-series/b30-hybrid-efficiency/
was probably most interesting but i've never heard one personally to gauge.
30 Hz ÷ 120 Hz
Max SPL @ 1m
133 dB
https://twaudio.de/en/product/b-series/b30-hybrid-efficiency/
was probably most interesting but i've never heard one personally to gauge.
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Qts': 2*Fs/Fhm = 0.5 minus some series resistance, so a ~0.4 Qts for such high power required
(Qts'): (Qts) + any added series resistance (Rs)
(Qts'): (Qts) + any added series resistance (Rs)
If you want decent response to 30Hz, the Fb (box tuning frequency) of a bass reflex box must be at least that low.
The TW Audio B30 Fb is around 45Hz, its response drops like a rock below that frequency, useless at 30Hz.
It's "hybrid horn" has no effect on it's low end output, which is less than a 2x15" of similar box dimensions.
The RCF 905a is a standard slot port bass reflex design using a 3" voice coil 15" driver, easy to build that type of box with as many drivers as you might choose.
Two single driver boxes give more placement options than a dual.
Nothing special about the 15" driver size regarding sound in the subwoofer range.
Powered by a 2200 W Peak, 1100 W RMS amp, the DSP (Digital Signal Processing) it uses is responsible for most of it's "tone".
The DIY options in making a good dual 15" subwoofer are only limited by your budget and skill level.
Art
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I would suggest to build a simple closed box with two good 15 inch woofers with high Xmax and low Fs (30 hz - 120 hz is only a woofer. Subwoofer goes below 30 hz). Use any powerfull amplifier, and a bass management system like minidsp, Trinnov or other DSP based bass management systems.
i had this conversation a few years back with JTR when he was first starting out which probably lead to the creation of the CAPTIVATOR PRO 215. But alas i have never heard one in person again so would have to wait until my ears can hear one personally..
I was recently able to A/B the 905as to the CAPTIVATOR PRO 212. And while the CAP would definitely win an output battle in the end the 905 still had a better overall tone and wasnt as direct. was interesting..
Hey Art thanks for joining in on discussion.. i know the 905as spec wise isnt spectacular but its something in the way and the port and speaker work together given the right signal it just sounds so much more musical than other options; that sound like either speaker, box, or port, but never a good combined two.
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JTR (Jeff Permanian) was starting his own company in 2006...
It was a while before Jeff got into the sub 30Hz range, the Captivator 215PRO has a 27Hz Fb.
A good compromise Fb for pro PA.
Jeff is fairly conservative in his settings:
The 2x18" (36mm Xmax) Captivator 4000ULF is a big "step down", a 10Hz Fb.
I think the 905a musicality has far more to do with RCF's DSP tuning than it's standard slot port and speaker arrangement.
I certainly don't consider the TW Audio B30's cartoonish 50Hz bump musical, but that response seems to be what users have become used too, so it sells.
Art
