http://home.new.rr.com/zaph/audio/temp/HIVIB3S-xover-1.gif
Here's the design. Note that this is preliminary and untested. This would be my first choice for a filter for this driver, as it gives a little more positive control over the response. The schematic, final response curve, impedence and transfer function are shown. The BSC can be adjusted with the R, and in some case the whole BSC circuit can be probably be removed - like when the system is up tight against a wall or sitting on top of a TV for center channel usage. Generally, away from walls is going to sound better, and putting these on little "surround stands" will offer the best sound. The .08 inductor will probably have to be unwound from a .10 Ask me for help on that if you need it.
http://home.new.rr.com/zaph/audio/temp/HIVIB3S-xover-2.gif
Here's another option similar to what I think Paul W was describing. The impedence dip isn't bad at all, but this sort of notch gives up a little control in the in the response shaping. Lowering the notch Q to widen the effective range and not cause a peak at 4Khz results in a peak that's not properly flattened. It would work, have a smoother impedence phase swing and probably sound good, but it's not my first choice.
The general rule for notches is that those within the bandwidth should be a parallel RLC in series with the driver + and those outside the bandwidth should be a series RLC shunt across the driver terminals. It's just a guidline really, but is true most of the time. The more you break this rule, the less control the notch has.
http://home.new.rr.com/zaph/audio/temp/HIVIB3S-enclosure.gif
Here's the box design. It's about .12 cu ft [3.3 l] and has a slim profile. I have designed the baffle to be removeable and fastened with socket head cap screws. there are .75" x 2" x 4" gussets to hold the T-nuts. One side of this gusset is cut at 45 degrees to minimize internal edge reflections near the cone. The gussets and internal width of 4" leave a 4" square to fit the crossover through with a removed baffle.
The baffle driver opening MUST have the inside routered at a 45 deg angle to promote airflow.
http://home.new.rr.com/zaph/audio/temp/HIVIB3S-inbox-nofilter.gif
Here's the predicted driver response in this box with no filter. Note that it only needs about 3 or 4 dB of BSC. This is a simulated baffle added on the the infinite baffle measurement. The 1/2" roundover on the baffle is also part of the simulation. These are usually surprisingly accurate though, and I wouldn't expect the final real in-box measurement to differ more than .5 dB.
http://home.new.rr.com/zaph/audio/temp/HIVIB3S-voicecoil.jpg
And just for the heck of it, here's what the voice coil and back of the cone look like. It's really a long voice coil and has more than twice the output of the old TB W3-871. The former is attached to the concave cone with a strengthening/alignment aluminum piece. The back side of the cone outside edge is coated with a damping material. Overall, pretty good construction for a cheap driver although the motor is really nothing special.
This is all preliminary. I'm in the process of building this myself, and there is a chance I may change something when I'm done and I post the final project.
The whole goal for this project is to address all possible usages for small speakers:
* Normal 2 channel stereo - on stands
* HT usage - TV top mounting
* Architectural audio - wall mounted
* Near field - desk mounted
I intend to test and provide options for each type of usage. I'll also provide upgrade options for a higher output and lower distortion system using the Aura NS3-193. This makes it a rather ambitous project, but the ever popular TB W3-871 system on my site is due for an upgrade. No promises on when I get it done. I'm easily distracted.
Very Excited
I for one am extremely excited about the NS3-193 version you will be making. I've been waiting to take the plunge on my first project. I needed small, and I was planning on building the W3-871 design, but didn't start because I wasn't sure it was right for me. The NS3-193 seems to be the exact project I'm looking for. Keep up the good work, and I can't wait to get started!
[/end butt kissing]
I for one am extremely excited about the NS3-193 version you will be making. I've been waiting to take the plunge on my first project. I needed small, and I was planning on building the W3-871 design, but didn't start because I wasn't sure it was right for me. The NS3-193 seems to be the exact project I'm looking for. Keep up the good work, and I can't wait to get started!
[/end butt kissing]
Hmm. Would you happen to have numbers for Bl and Sd that are any good? Trying to make a very vaguely educated guess suggests that Bl may be around 3 but that's a bit dependant on Sd... at any rate, it's shaping up to look surprising in a TQWP, but that is a bit dependant on Bl and Sd for me to get it right. In fact, if it *does* work out, the potential for a rather elegant (and perhaps insane) design is quite high.
Thanks for all your work, whether you have these numbers or not!
Can't wait to hear whatever you bring this year.
C
In fact, if it *does* work out, the potential for a rather elegant (and perhaps insane) design is quite high.Thanks for all your work, whether you have these numbers or not!
Can't wait to hear whatever you bring this year.
C
cjd said:
The BL is about 3.5, and the Sd is about 30.2 cm^2. If you want to play around with bass alignments, most of what you need can be found here. Notice how high the Qts is, which I suspect is why this driver only needs 3 or 4 dB of BSC - the midbass peaking partially makes up for the low end 2pi-4pi rolloff. The scary thing about putting these in any kind of enclosure other than small sealed is the power handling.
coolkhoa said:
There's a round flange version of this driver which I'm pretty confident is the same thing. It would need to be countersunk though. Rear mounted could work ok, but I don't think I'd do it with a baffle more than 1/4" thick even if it's rounded over. The hole edge tends to affect the response curve a little. As far as looks, it looks pretty classy with 4 socket head cap screws holding the driver in place.
Thanks for those specs! I'll have to run 'em through Mathcad tomorrow. If I remember, power handling peaks out at about 85dB at 1M in the TQWP I was messing with, but I was pondering something that could give good bass and be interesting enough (perhaps) to pass more SAF tests than usual. Not for HT, but perhaps for music. Given that I usually listen with nominal levels in the 50's and peaks in the mid 70's, that still would work at 3M for me with a little room left over. And, response to 40Hz. Out of a single 3" driver. Your numbers are different enough that I don't believe a bit of that, and I'll go re-run the model to see how bad it screwed things up.
IF it still works out, expect to see some at DIY Chicago 2005. If my wife doesn't kill me first.
C
IF it still works out, expect to see some at DIY Chicago 2005. If my wife doesn't kill me first.
C
so is this the successor to the throne once held by the TBs? they look pretty good, just wondering if a tweeter would be necessary for these things to be well rounded (at least in the upper frequencies)? i'm looking into doing a new speaker setup for my HT and these things would work great with a sub. thinking maybe single drivers (plus tweet?) for center and rears, while doing the fronts with 4 each plus maybe the tweeter. i have to keep it 8 ohm (reciever not 4 ohm capable, and i know this can be discussed over in regards to higher freq.)
Ported and LT...
Yea I'm interested in these things -- or more possibly the Aura one that will follow this.... When they are all made and optimised we will know which is the winner after all...
Funny thing is that both the Aura and the B3S model well in a ported design with a high pass filter and a linkwitz transform... REALLY well actualy
Flat to 60hz and the hivi hits its excursion limit 3dB lower thn its thermal limit - -and the aura hits them at the same time...
Aura in a 1.5 cuft box tuned to 60 hz, 4th order LR highpass @ 55-60 hz depending on how much of a peak you want near tuning, linkwitz transform of:
f(0) = 97.15 Hz
Q(0) = 0.83
f(p) = 50 Hz
Q(p) = 0.500
C2 = 0.047 µF
R1 = 16.84 kOhms
R2 = 8.32 kOhms
R3 = 63.57 kOhms
C1 = 0.201 µF
C3 = 0.0534 µF
B3S also looks good in:
1.5 cuft tuned to 55hz, 4th order LR hp @ 55-60, linkwitz transform:
f(0) = 115 Hz
Q(0) = 1.22
f(p) = 60 Hz
Q(p) = 0.707
C2 = 0.047 µF
R1 = 10.41 kOhms
R2 = 3.31 kOhms
R3 = 38.26 kOhms
C1 = 0.376 µF
C3 = 0.1023 µF
Someone else should give this a looksie over before anyone goes and actualy does anything with it but yea... It looks good to me...
BTW Ive never seen anyone use a LT with a ported design along with a highpass to cut the peak.... Utilizing this leads to less cone excursion arround the tuning frequency as well as less gain needed due to slightly increased efficency. Is this a first? Fullrange speaker in a small box from 60hz to ~16-20khz!!!
This same idea can be used in a small ported or PR box as well Say a small subwoofer tuned to 16-18hz getting the group delay peak below 20hz and less audable. The problem with a small box tuned so low is simply the port needs to be very long. A high mass PR would work though... Try modeling in winisd any sealed box subwoofer you want, add a port tuned to 16-18hz to the same box volume and compare. Now compare it to a sealed box responce of about .1qtc lower (ie if it was .707 compare, a .607 to the ported...) look simmilar dont they? Also note cone excursion plots... Add a linkwitz transform and you wont bottom the driver so quickly now will you? Past the tuning things go off the chart however but a subsonic filter will take care of that.
Yea I'm interested in these things -- or more possibly the Aura one that will follow this.... When they are all made and optimised we will know which is the winner after all...
Funny thing is that both the Aura and the B3S model well in a ported design with a high pass filter and a linkwitz transform... REALLY well actualy
Flat to 60hz and the hivi hits its excursion limit 3dB lower thn its thermal limit - -and the aura hits them at the same time...
Aura in a 1.5 cuft box tuned to 60 hz, 4th order LR highpass @ 55-60 hz depending on how much of a peak you want near tuning, linkwitz transform of:
f(0) = 97.15 Hz
Q(0) = 0.83
f(p) = 50 Hz
Q(p) = 0.500
C2 = 0.047 µF
R1 = 16.84 kOhms
R2 = 8.32 kOhms
R3 = 63.57 kOhms
C1 = 0.201 µF
C3 = 0.0534 µF
B3S also looks good in:
1.5 cuft tuned to 55hz, 4th order LR hp @ 55-60, linkwitz transform:
f(0) = 115 Hz
Q(0) = 1.22
f(p) = 60 Hz
Q(p) = 0.707
C2 = 0.047 µF
R1 = 10.41 kOhms
R2 = 3.31 kOhms
R3 = 38.26 kOhms
C1 = 0.376 µF
C3 = 0.1023 µF
Someone else should give this a looksie over before anyone goes and actualy does anything with it but yea... It looks good to me...
BTW Ive never seen anyone use a LT with a ported design along with a highpass to cut the peak.... Utilizing this leads to less cone excursion arround the tuning frequency as well as less gain needed due to slightly increased efficency. Is this a first? Fullrange speaker in a small box from 60hz to ~16-20khz!!!
This same idea can be used in a small ported or PR box as well Say a small subwoofer tuned to 16-18hz getting the group delay peak below 20hz and less audable. The problem with a small box tuned so low is simply the port needs to be very long. A high mass PR would work though... Try modeling in winisd any sealed box subwoofer you want, add a port tuned to 16-18hz to the same box volume and compare. Now compare it to a sealed box responce of about .1qtc lower (ie if it was .707 compare, a .607 to the ported...) look simmilar dont they? Also note cone excursion plots... Add a linkwitz transform and you wont bottom the driver so quickly now will you? Past the tuning things go off the chart however but a subsonic filter will take care of that.
Re: Ported and LT...
Ok, I'm back. I had to roll around on the floor and laugh for a while. Did you say 1.5 cu ft? I think I have a few better options for a 1.5 cu ft enclosure than putting a 3" driver in it.
With a few rare exceptions, (and this is my opinion) no woofer 4" or smaller should be ported, and no woofer with an excessively high Qts should be ported. Power handling and group delay are much more important than bass extension.
And another opinion, Linkwitz transform circuits are better used for larger woofers, regardless if Q goes up or down.
And lastly, relying on WinISD for anything is a bad idea. When that program properly models the real room effect, it might become more useful. (I haven't checked what the recent versions can do)
AAXenoStrange said:
Ok, I'm back. I had to roll around on the floor and laugh for a while.
Did you say 1.5 cu ft? I think I have a few better options for a 1.5 cu ft enclosure than putting a 3" driver in it.With a few rare exceptions, (and this is my opinion) no woofer 4" or smaller should be ported, and no woofer with an excessively high Qts should be ported. Power handling and group delay are much more important than bass extension.
And another opinion, Linkwitz transform circuits are better used for larger woofers, regardless if Q goes up or down.
And lastly, relying on WinISD for anything is a bad idea. When that program properly models the real room effect, it might become more useful. (I haven't checked what the recent versions can do)
wow what a brain-O
haha meant .15cuft sorry about that its been a long tiring -- few months 2 many projects mixing up in my head as well...
BTW only used winisd to check and make sure that the little cone wasnt going past xmax at some unreasonable power input as well as get a feel for an effective f3 with a linkwitz transform in place... If someone has a better program I'd really like to see those numbers be confirmed or disproved in something other than winisd. The only possible problem is a scary group delay centered at 55hz and spanning about 1/2 an octave on both sides due to the sharp transfer function right after 60hz.
winisd says for what its worth that a .13cu sealed reaches xmax for the aurasound with ~12-13 watts between 20-60hz
max spls limited by RMS power and excursion are as follows at these points (Take these as little more than a grain of salt...):
60hz = 83.2dB (Xmax limited with 12.5W of power)
80hz = 88.4dB (Xmax limited with 14.2W of power)
100hz = 92.25dB (Power and Xmax limit reached at same time)
150hz = 94.6dB (Power limited)
The massively filtered .15 ported:
60hz = 96.6dB (Power limited @ 20W, 2mm of xmax used)
80hz = 95.5dB (Xmax limited @ 18W)
100hz = 96.2dB (Power and Xmax limit reached at same time, xmax slightly before though)
150hz = 96.2dB (Power limit @ 20W, 2.48mm of xmax used)
The ported design has consistently higher group delays due to the high pass filter above tuning, however that is a fairly constant delay/frequency.
I just think it is something to keep in mind particularly for HT... That group delay peak may hurt music, however you can always plug the port with a sock and you go back to a .5qtc sealed box with an excursion limiting filter....
A look at the apparent load to the amplifier also reassures that the linkwitz transform will not cause the amp to zap the voice coil as the load is consistently under 10VA under 100hz. This should help to keep compression levels down as well.
haha meant .15cuft sorry about that its been a long tiring -- few months
2 many projects mixing up in my head as well...BTW only used winisd to check and make sure that the little cone wasnt going past xmax at some unreasonable power input as well as get a feel for an effective f3 with a linkwitz transform in place... If someone has a better program I'd really like to see those numbers be confirmed or disproved in something other than winisd. The only possible problem is a scary group delay centered at 55hz and spanning about 1/2 an octave on both sides due to the sharp transfer function right after 60hz.
winisd says for what its worth that a .13cu sealed reaches xmax for the aurasound with ~12-13 watts between 20-60hz
max spls limited by RMS power and excursion are as follows at these points (Take these as little more than a grain of salt...):
60hz = 83.2dB (Xmax limited with 12.5W of power)
80hz = 88.4dB (Xmax limited with 14.2W of power)
100hz = 92.25dB (Power and Xmax limit reached at same time)
150hz = 94.6dB (Power limited)
The massively filtered .15 ported:
60hz = 96.6dB (Power limited @ 20W, 2mm of xmax used)
80hz = 95.5dB (Xmax limited @ 18W)
100hz = 96.2dB (Power and Xmax limit reached at same time, xmax slightly before though)
150hz = 96.2dB (Power limit @ 20W, 2.48mm of xmax used)
The ported design has consistently higher group delays due to the high pass filter above tuning, however that is a fairly constant delay/frequency.
I just think it is something to keep in mind particularly for HT... That group delay peak may hurt music, however you can always plug the port with a sock
and you go back to a .5qtc sealed box with an excursion limiting filter....A look at the apparent load to the amplifier also reassures that the linkwitz transform will not cause the amp to zap the voice coil as the load is consistently under 10VA under 100hz. This should help to keep compression levels down as well.
Well they arent done yet -- I'm kind of curious about their ETA and if/when an aurasound project will be done
Kind of like a 3 way comparison between these full ranges -- May build a pair of each and take them to Dayton next year for people to hear... And that little experiment that I want to do as well...
Kind of like a 3 way comparison between these full ranges -- May build a pair of each and take them to Dayton next year for people to hear... And that little experiment that I want to do as well...
AAXenoStrange said:Well they arent done yet -- I'm kind of curious about their ETA and if/when an aurasound project will be done
Kind of like a 3 way comparison between these full ranges -- May build a pair of each and take them to Dayton next year for people to hear... And that little experiment that I want to do as well...
This is my last post until I get these done. Consider this an update. I'm painfully slow at building enclosures. January in Wisconsin doesn't help much. Last week it was about -5 deg F in my garage. Too easy to saw your fingers off when you can't feel them
Additionally, we keep the temperature inside the house at 65 deg F. That helps keep our gas bill under $250 but it also takes paint and varnish and everything else forever to dry. It could be a while before I finish.These are the boxes so far using Aegean stain and a clearcoat. The baffles are not started yet. This same box will be used for both the HiVi and Aura versions.
home.new.rr.com/zaph/audio/temp/newminiboxes.jpg
Here's an idea for desktop stands. They are not built yet, it's just a concept, so there are no dimensions. Rear mounted "L" brackets and an adjustment knob allow continuously variable vertical angles. The height of this bracket will depend on whether a monitor riser is in use. If not, they will have to be taller.
home.new.rr.com/zaph/audio/temp/newministands.gif
A couple more clearcoats and I'll be ready to start on the baffles. I'll be back when they're done.
Ps. If anyone's interested in using the B3N instead of the B3S, I'll offer to measure them to see if they are the same, and then send them back when done. Contact me via the email listed at my website for info.
Another update...
Keeping this thread rolling with updates until completion. I guess this thread is kind of a design journal. I got the boxes and baffles done, for both the B3S and NS3. Here here's one of them.
home.new.rr.com/zaph/audio/temp/HIVIB3S-system.jpg
Some of you were wondering about the B3N, if it was the same as the B3S. It is not. As far as the cone, surround, spider and motor assembly, I think it's the same, but it looks like the frame is causing some response differences. The image below is 2 B3N samples on an infinite baffle. The differences shown are consistent with frame edge diffraction of a surface mount driver of this size. I suspect flush mounting the driver might help some of this, but not all of it. I may later do a response test with the driver countersunk to see if the response matches up closer to the B3S.
home.new.rr.com/zaph/audio/temp/HIVIB3N-channelmatching.gif
The image below is the in-box anechoic full range response of the B3S. It's close to my predictions although a little off in the 400-800 range. Notice how the B3S breakup node is symetrical on bother sides. This makes it easy to fix with one notch.
home.new.rr.com/zaph/audio/temp/HIVIB3S-channelmatching.gif
And finally, here's one B3S and B3N together to show the differences. For now, this design is sticking the the B3S. The B3N would probably work alright though, just needing an extra db or 2 of BSC to help the lessen the effect of the higher output in the 3-5khz range.
home.new.rr.com/zaph/audio/temp/HIVI-B3S-B3N.gif
So far I've taken measurements in a whole load of locations, mostly to address the "architectual audio" possible uses near boundaries. If things go well, I'll get to work on these this weekend. I'm thinking I'll probably just post the HiVi version first and then do a later update addressing the Aura NS3-193 version. (man, those sure have deep bass and healthy output for a 3" driver)
Keeping this thread rolling with updates until completion. I guess this thread is kind of a design journal. I got the boxes and baffles done, for both the B3S and NS3. Here here's one of them.
home.new.rr.com/zaph/audio/temp/HIVIB3S-system.jpg
Some of you were wondering about the B3N, if it was the same as the B3S. It is not. As far as the cone, surround, spider and motor assembly, I think it's the same, but it looks like the frame is causing some response differences. The image below is 2 B3N samples on an infinite baffle. The differences shown are consistent with frame edge diffraction of a surface mount driver of this size. I suspect flush mounting the driver might help some of this, but not all of it. I may later do a response test with the driver countersunk to see if the response matches up closer to the B3S.
home.new.rr.com/zaph/audio/temp/HIVIB3N-channelmatching.gif
The image below is the in-box anechoic full range response of the B3S. It's close to my predictions although a little off in the 400-800 range. Notice how the B3S breakup node is symetrical on bother sides. This makes it easy to fix with one notch.
home.new.rr.com/zaph/audio/temp/HIVIB3S-channelmatching.gif
And finally, here's one B3S and B3N together to show the differences. For now, this design is sticking the the B3S. The B3N would probably work alright though, just needing an extra db or 2 of BSC to help the lessen the effect of the higher output in the 3-5khz range.
home.new.rr.com/zaph/audio/temp/HIVI-B3S-B3N.gif
So far I've taken measurements in a whole load of locations, mostly to address the "architectual audio" possible uses near boundaries. If things go well, I'll get to work on these this weekend. I'm thinking I'll probably just post the HiVi version first and then do a later update addressing the Aura NS3-193 version. (man, those sure have deep bass and healthy output for a 3" driver)
And to think that just last night I FINALLY soldered up John's notch for the 871s and installed them after running them unfiltered for a year, and now he's got a new project for me to try!
Anyway, great info John. Now I'm off to convince my girlfriend of all the benefits to having speakers in the kitchen!
Anyway, great info John. Now I'm off to convince my girlfriend of all the benefits to having speakers in the kitchen!
Jim85IROC said:
If she enjoys cooking at all, this one is a slam-dunk. Wiring music into the kitchen is probably my all-time biggest "Thank you, Honey!" score.
I'm actually really annoyed at John's mini-full-range testing etc. He came out with it *right* after I shelled out for a flight of 2" Auras. They'll probably still work for what I need, but the B3S looks better and would be half the price. Oh, well, if my prototype with the Auras works out, I guess the Hi-Vi's are cheap enough that I can 'upgrade'.
I just ordered the B3Ns yesterday and they'll be here in about 4 hours! Now that I see how nice the B3Ss look with John's mounting method, and seeing they have a nicer response, I guess I should have waited one more day 
Oh well, I'm sure they'll sound fine!
Thanks again, John. You are THE MAN!
Oh well, I'm sure they'll sound fine!
Thanks again, John. You are THE MAN!
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