Hi-Vi B3S vs Hi-Vi B3N vs Aura NS3-193 for computer speakers?

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I would like to build a pair of desktop computer speakers similar to John Krutke's Hi-Vi B3S single driver system (http://www.zaphaudio.com/audio-speaker18.html). But I'm having trouble choosing a driver. If cost is no object, which of these three drivers (Hi-Vi B3S, Hi-Vi B3N, Aura NS3-193) would be best in a single-driver system? Any other drivers that I should consider? I haven't seen any real comparisons between these.

I prefer the shape of the B3N to the B3S. Does anyone have the TS parameters for the B3N? I have found the data sheet for it, but the data sheet parameters always seem to be a bit different to the real-world measurements. John Krutke has TS parameters for the other two on his website. I need to choose a driver so that I can buy a couple and start measuring.

I have some measurement equipment. What design software is recommended? I have been trying to use Speaker Workshop, but it's not very intuitive. Soundeasy looks really good, but I can't afford that right now.

A subwoofer will be added in the future. I want a single driver setup because driver integration becomes a problem with multiple drivers at such a close listening distance. The speakers will be stand-mounted on a desk, 2-3ft from the listening position, and ~1ft from the wall. I have a NAD C320 BEE (55 Wpc) that I'm not currently using for anything, so I'll probably use that to power these speakers.

I have never designed a speaker before and want to learn the design process. I have built two pairs of GR-Research AV1s from kits and have been reading DIY audio stuff for ~2 years, though, so I have some idea of what's going on :).

Thanks
 
HiVi B3S

I took John Zaph's word for it and bought a pair of the B3S & made some boxes out of Pergo flooring I had around. My Saw Could only cut 8 inches, so I just "winged it " on these cabinets, they are much more cubic than John's long skinny design. I added a cheapo subwooofer & am driving with an older Aiwa mini-receiver, & I think they sound great (so does everybody else that listens). I don't have any sophisticated test equipment to measure the frequency response, nor did I bother to make that band-pass crossover (I have 100 uF rolled poly caps on the ViFi's)
John Zaph is a perfectionist, & IMHO minor deviations from his design are not going to be noticiable to the average person. Last year I built a pair of the Tang-Band speakers & was very happy with them also. A note-a 3" hole saw will work, just be very careful and neat positioning the screw holes and the flange will just barely cover this hole. Again, for the cost and size, you can't beat these speakers with anything from Best Buy for less than $300. Good Luck, & don't be a perfectionist, & be happy with great sound.
 
Thanks for the response. I actually bought a pair of B3N's (the ones with the round mounting flange) about a week ago. I haven't done much with them so far, but I hope to get boxes built in the next 2-3 weeks. I have measurement equipment, so I'll take some measurements then and see if I can improve the sound with a filter.

Does it make much difference where the driver is placed (vertically) on the baffle - if I placed the driver closer to the top rather than the middle?
 
Some thoughs...

Driver placement definately makes a difference. Since these will be computer speakers, I recommend you place the drivers close to the top of the baffle, to delay and minimize reflections from your desk, and to get them close to ear level.

For better results, try placing them so the distance between the center of the driver and the top edge is 1.6 the distance to the side edge. (Ex: if the baffle is 8 inches wide, the center of the speaker should be 6.4" from the top.)

You definately want a notch filter to reduce the cone break up around 7700hz. The caps, coils and resistors will cost you about $8. Even if you have no measurement equipment, wing it and buy .10mhz coils, 4.3uf caps, and 30 ohm resistors. Connect these parts in parallel, then connect them in series with the speaker. The result will not be ideal, but it will be much better than no filter.

If you plan on placing the speakers directly next to your monitor, you can get away with not using baffle step compensation.

Use a subwoofer, these speakers don't like to play low. An active 2nd order xover at 150hz will give good results.

These speakers need a considerable amount of break in. Expect bass to improve during the first 100 hours of play.

When you build the enclosure, make sure to round off the back of the speaker cutout. The shielded magnet is very big and leaves little breathing room for the back of the driver.

Link to my HiVi B3S thread
Dan
 
Thanks for the tips :) I've studied John's B3S design thoroughly and I'm using it as a general guideline. But, I'm using a slightly different driver and a slightly different size/shape box (checked for standing wave problems), so I'm going to try and optimize my version. I haven't settled on final box dimensions yet, but I was thinking something like this: 7.75" x 4.125" x 8.5" (LxWxH internal) with 0.75" MDF. Stuffed with Acousta-stuf.

I have also been watching your B3S bipole design closely :) Looks like it's coming along well so far.

Mike
 
I've started putting together the boxes. I'm still wondering about the vertical driver placement. Here are the box dimensions

Internal:
H: 7.75"
W: 4.25"
D: 6.5"

External (0.75" MDF):
H: 9.25"
W: 5.75"
D: 8"

I want to place the drivers above the center line of the boxes. All edges of the baffle will have a 0.75" radius.

The 1.6 method mentioned by Dan (owdi) doesn't really work in this case: 1.6 x 2.875" (half baffle width) = 4.6" from the top, which is just slightly above the center line.

Any other tips for vertical driver placement? If it doesn't really matter, then I'll just choose something that looks good.

Thanks,
Mike
 
Be sure to use braces on the cabinet walls, strips of MDF aren't particularly good for that purpose, little solid wood boards are good. Cabinet vibrations really have a large detrimental effect on the sound. I would recomend damping also but that is not so simple as bracing.

If you are interested in damping, a relatively quick, easy, and effective solution is: prepare the inner cabinet surface (where you want to damp, the front being one of the more important places) by coating it with contact cement, or something similar. After it dries stick on one or two layers of "roof repair tape". The reason for the contact cement is that the tape will bond much more securly/permanently than to just a plain wood/MDF surface.
 
Sry to bring this old thread back to life, but it seems that some of you have built his B3N set.
I'm going to also, but I'm having trouble with ratings on the resistor and capacitors used.

I will power the B3Ns with 100watt max! and a cut-off around 150-200hz (active filter).

How do you determine the wattage rating needed for the resistor in the notch filter and the baffle step correction?

The only resistor I can find is 27ohm or 33ohm, but will this degrade performance noticably?


What voltage rating is needed for the bipolar caps? 100v?
 
if you double the drivers, you have to be exactly the right distance from both drivers to your ears.

Sitting at a cpu, I believe it would be very bad to have 2 drivers in 1 box (unless baffle step or crossover).

My dual 4" is very sensitive to vertical listening sweet spot 12' away............

Someone else ran dual x 3" or 4" drivers sitting at a cpu over on the full range driver forum and heard a phasy sound all the time.

Norman
 
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