OB Full Ranger

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I have been asked by a friend to design and eventually build them a sound system and today I started looking into it.

Goals:
-Wide dispersion
-Somewhat high output capabilities, able to hit at least 100 dB with ease
-Under $500 for the system

Heres my idea:

I really like the look of the OB hybrid speakers Versal did (here) and I like open baffle in general. I was thinking if I did something similar to this with some 2" full rangers I could get good HF dispersion and if I crossed it over relatively high (100-200Hz) I could get some good power handleing.

I was thinking the Vifa NE65W-04 is a good option because its got good excursion for that price and size. I would run it with a Lepai TA2020 (same thing I use in my own system) and wouldn't worry about her blowing the drivers.

I would high pass it in the 100-200Hz range and then actively cross to the "sub"woofers with two Dayton 25W plate amps. I prefer this sort of crossover to passive just because of flexibility of volume and crossover without expensive components. I like high efficiency subs so this would do fine even at its low power. Instead of the ported speaker like Verasl did I want to use a horn subwoofer, sort of like this. I only really need response down to 35ish Hz because its going to be a music system and I don't feel the need to use huge cabs to get that low.

I want to use the 12" Dayton woofers I used in my own sub because they are cheap and I know they are good. With two of them the excursion isn't too much of a problem and should put out plenty of SPL for her in a horn sub.

So far the budget is up to about $260 in parts if your keeping track. This leaves me about 240 to work with for cabinets and LEDs (she wants some sound sensitive lights, it'll cost about $90) so $150 for cabinets. I'm pretty crafty and with OBs for the full rangers I think I can build the cabinets for about that much.

Max total power consumption of the system would be about 70w which isn't bad for a pretty efficient system. The person I'm building it for I would not consider an audiophile so I've made some choice compromises to save cost where she probably won't even notice. Also I don't want her to be able to drive any of the drivers over excursion with the amps I give her, she probably won't watch her excursion like I do when turning it up.

Being a teen she probably likes big bass so its OK if the full rangers won't get quite as loud as the subs because they will be at a lower relative volume anyway when the system is loud.

I will probably go with either an all black, all white, or a combo glossy finish to keep finishing costs down, veneer is expensive :eek:

How does all of this sound? Is there anything that sticks out as a problem?
 
The Vifa NE65W-04 is way too small to work down to 200 Hz. Don't look any smaller than 4" if you want to cross that low. A long stroke 4" like TB W4 1052SD, Tang Band W4-1879 or Tang Band W5-1611SA could do the job. And be prepared to raise the xover frequency up to 400 Hz depending on the SPL involved. :)

I hope you are aware that any dipole driver should be at least 3 feet away from the wall behind it.

Rudolf
 
The Vifa NE65W-04 is way too small to work down to 200 Hz. Don't look any smaller than 4" if you want to cross that low. A long stroke 4" like TB W4 1052SD, Tang Band W4-1879 or Tang Band W5-1611SA could do the job. And be prepared to raise the xover frequency up to 400 Hz depending on the SPL involved.
smile.gif

How is the dispersion on those? The W4-1879 is a bit expensive for my budget but the other two look like possibilities. How is the dispersion on those other two? I would like it to be listenable to at least 30 degrees off axis.

I want to cross as low as possible because of the ragged upper response of horn subwoofers. I could probably cross those larger drivers around 120hz which should be low enough for this. I've used some larger full rangers before and I think either of those will easily cover my spl requirement with the lows filtered out
I hope you are aware that any dipole driver should be at least 3 feet away from the wall behind it.

The sub will likely be around 3 feet deep and the full ranger will be on front so this should be fine.
 
For your SPL requirements you have to look at your amplifier and for low frequencies at the diaphragm area/displacement.
The TA2020 is 2x20W. At 20W you get +13dB. So with a 87dB speaker you will reach the 100dB at maximum amplifier output!
To reach 100dB at 200/120Hz with 18mm2 (Vifa) you need ~5.5/15 mm displacement.
With the TB 4" (57mm2) ~1.7/4.5 mm
With the TB 5" (94mm2) ~1/2.7 mm
 
How is the dispersion on those?... I would like it to be listenable to at least 30 degrees off axis.
The W5-1611SA has quite a following round here. 15° response is very near to 0°. 30° stays within 5 dB from 0° up to 6 kHz, but falls off rapidly after that. Don't know anything about the W4 1052.
I want to cross as low as possible because of the ragged upper response of horn subwoofers. I could probably cross those larger drivers around 120hz which should be low enough for this.
The W5-1611SA shows practically no compression at 100 dB, when crossed over at 200 dB. Distortion will raise below 200 Hz too. You should really try to keep the Xover there.
The sub will likely be around 3 feet deep and the full ranger will be on front so this should be fine.
For sure!
 
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