SB12mnrx2 crossed at 300-3800Hz LR2 (40W to get 100 dB)
FP 5fe120 crossed at 250-2800Hz LR2 (30W to get 100 dB)
FP 5fe120 crossed at 250-2800Hz LR2 (30W to get 100 dB)
An other possible low cost woofer.
FANE 12-500LF.
In 70 Br 44/38/30.
Itnhas the davantage of having 94.5 DB (computed)
FANE 12-500LF.
In 70 Br 44/38/30.
Itnhas the davantage of having 94.5 DB (computed)
Hard to beat (at the price specially ... while it lasts!). Famously used in the Kii designs.
https://en.toutlehautparleur.com/br...r-peerless-fsl-0512r01-08-8-ohm-5-9-inch.html
Attachments
In mycurrent process of implementing the SIG180-4 and trying to wring the best out of it, I find the 3kHz bump to still be breakup and require suppression. I think it would be lucky to get 2.5kHz at the top end of it. My usage is targeting 2.4kHz, and that blends to an LR6 relatively easily with a damped 2nd order and LCR across it for the breakup. For reference, the series notch across the driver is 1.2mH - 2.0uF - 1.2 ohms (coil DCR plus resistor).
The SB12MNRX can realistically deal with 60 - 70 w continuous if chambered correctly. The trick is to land just above the midrange resonance impedance peak Fc with the midrange HP slope. Operating around the driver's resonance reduces VC current at a given drive voltage and raises efficiency down low. It also controls excursion by means of less compliance just at and above the Fc cutoff area. You also can use this higher frequency mechanical rolloff to supplement the mid's electrical HP slope, only requiring a series capacitor to achieve a 2nd order HP. If you chamber the mid too large, it throws away all these benefits. I found that you could potentially double a mid's power handling just by installing it in a smaller chamber.
@wolf_teeth Keep in mind all these crossover parts cost money. This is why its important to choose a driver from a crossover implementation standpoint. That LCR adds about 15$ of parts in addition to the other HP and LP filter components.
Extreme budget garage speakers that started with crappy boxs bought at a garage sale. Dayton Audio DC200-8, Goldwood GH 85/8, Peerless BC25SC55-04, total cost of drivers a couple years ago, $120 for both speakers.
Yes. While the cone profile and cone material can make a difference, the driver diameter will be the most important determinant of when it beams. Below are the polars of an ideal driver on a 15-1/2 inch wide by 27 inch tall baffle with the midrange placed where I think it will end up with this design. The divers are based on the Sd of the SB12MNRX, 5FE120 and SIG180.
That I don't know. It may be that a more directive (larger midrange) is actually better on this wide baffle as we get more direct radiation and less reflected from the baffle. Smarter people than me can address that.
Yes, absolutely, see the gifs below...
A dimensional survey, in alphabetical order, in Height x Width x Depth
Genelec
1237A (ported 12")
68 x 40 x 38 cm
26 3/4 x 15 3/4 x 15 in
Harbeth
M40.5 XD2 (ported 12")
75 x 43 x 39cm
29.528 x 17 x 15 1/3"
JBL
L100 Century (1975) (ported 12")
60 × 36 × 36 cm
23½ × 14¼ × 13⅝″
L100 Classic / mk II (ported 12")
64 x 39 x 37 cm
25 x 15 1/3 x 145/8 "
Neumann
KH420 (ported 10”)
64.5 x 33 x 44 cm
25 3/8 in 13 in 17 1/2 in
Yamaha
NS1000 ~1987 (sealed box 12")
71 x 40 x 37 cm
28" x 15 3/4 x 14 1/2 "
NS5000 (ported 12”)
69 x 39.5 x 38.1 cm
15-1/2” x 27-1/8” x 15”
As I will not be building this speaker, I will leave it the group to decide their dimensional preferences.
2. Re: SB Acoustics SB12MNRX2
For those who want to build a classic 3-way where all of the clever work has been done, and the SB12MNRX2 midrange is used, consider SB Acoustics GEMA (also has 26mm soft dome SB26STAC and 12" SB34NXRL-8)
https://sbacoustics.com/product/gema/
Thank you @USXX
Based on the FR and impedance data, there is a slight dip/blip around 1K5 Hz, and cone breakup is significantly rises above 6KHz (60 degree off axis data), so the ideal upper limit of this driver is around 3KHz.
Reference: https://sbacoustics.com/product/4-sb12mnrx2-25-4-norex/
If one is to consider the SB12MNRX2-25-4, I think it would be prudent to also consider the Tymphany NE123W-4
Although this slightly lower in sensitivity (88.75dB / 2.83V (4 ohm) Ref: 1KHz), the upside is that it has slightly larger 1-1/4" voice coil wound on a titanium former, a full copper cap for lower odd order distortion.
At first glance it's frequency response may not appear as smooth as the SB12MNRX2-25-4, but sometimes it's challenging to compare because different manufacturers measure in different ways, and also display in different ways.
Here I make an attempt to scale the X and Y axis to be similar, and on closer inspection it's first cone edge dip is around 2KHz. The upper end of the frequency response becomes chaotic past 6.7KHz, so the ideal upper limit of this driver is around 3.3KHz
Please note that when I say ideal , this does not mean this is a hard boundary. Attention needs to be paid to the tweeter it's matching to and how to speaker baffle affects the response.
What do you think @profiguy about the NE128W-4
It's coming back into stock at Parts Express:
https://www.parts-express.com/Peerless-NE123W-04-4-Paper-Cone-NE-Woofer-4-Ohm-264-1512?quantity=1
I would would guess that it may come back into stock in Europe via SoundImports.EU or other also.
I believe (not have no evidence for) that the midrange is important to get right.
Disclaimer:
I have used the NE123W-8 in pairs, as part of the @jholtz and Curt Campbell Statements II, and I have fond recollection of this speaker.
Genelec
1237A (ported 12")
68 x 40 x 38 cm
26 3/4 x 15 3/4 x 15 in
Harbeth
M40.5 XD2 (ported 12")
75 x 43 x 39cm
29.528 x 17 x 15 1/3"
JBL
L100 Century (1975) (ported 12")
60 × 36 × 36 cm
23½ × 14¼ × 13⅝″
L100 Classic / mk II (ported 12")
64 x 39 x 37 cm
25 x 15 1/3 x 145/8 "
Neumann
KH420 (ported 10”)
64.5 x 33 x 44 cm
25 3/8 in 13 in 17 1/2 in
Yamaha
NS1000 ~1987 (sealed box 12")
71 x 40 x 37 cm
28" x 15 3/4 x 14 1/2 "
NS5000 (ported 12”)
69 x 39.5 x 38.1 cm
15-1/2” x 27-1/8” x 15”
As I will not be building this speaker, I will leave it the group to decide their dimensional preferences.
2. Re: SB Acoustics SB12MNRX2
For those who want to build a classic 3-way where all of the clever work has been done, and the SB12MNRX2 midrange is used, consider SB Acoustics GEMA (also has 26mm soft dome SB26STAC and 12" SB34NXRL-8)
https://sbacoustics.com/product/gema/
Thank you @USXX
Based on the FR and impedance data, there is a slight dip/blip around 1K5 Hz, and cone breakup is significantly rises above 6KHz (60 degree off axis data), so the ideal upper limit of this driver is around 3KHz.
Reference: https://sbacoustics.com/product/4-sb12mnrx2-25-4-norex/
If one is to consider the SB12MNRX2-25-4, I think it would be prudent to also consider the Tymphany NE123W-4
Although this slightly lower in sensitivity (88.75dB / 2.83V (4 ohm) Ref: 1KHz), the upside is that it has slightly larger 1-1/4" voice coil wound on a titanium former, a full copper cap for lower odd order distortion.
At first glance it's frequency response may not appear as smooth as the SB12MNRX2-25-4, but sometimes it's challenging to compare because different manufacturers measure in different ways, and also display in different ways.
Here I make an attempt to scale the X and Y axis to be similar, and on closer inspection it's first cone edge dip is around 2KHz. The upper end of the frequency response becomes chaotic past 6.7KHz, so the ideal upper limit of this driver is around 3.3KHz
Please note that when I say ideal , this does not mean this is a hard boundary. Attention needs to be paid to the tweeter it's matching to and how to speaker baffle affects the response.
What do you think @profiguy about the NE128W-4
It's coming back into stock at Parts Express:
https://www.parts-express.com/Peerless-NE123W-04-4-Paper-Cone-NE-Woofer-4-Ohm-264-1512?quantity=1
I would would guess that it may come back into stock in Europe via SoundImports.EU or other also.
I believe (not have no evidence for) that the midrange is important to get right.
Disclaimer:
I have used the NE123W-8 in pairs, as part of the @jholtz and Curt Campbell Statements II, and I have fond recollection of this speaker.
This is why I reported my findings. I'm not sure it is a good choice for a midrange for the AMC being discussed here because it is bandwidth limited to 2.4k, and needs more parts to get there.
@tktran303 The NE123W and NE149W are excellent mids, sincerely better than the SB12MNRX (if you can get ahold of them). The NE123W would be my first recommendation for a reasonably priced mid if the sensitivity was fitting for your design. Keep in mind the Ti former has drawbacks in terms of power handling due to its poor thermal conductivity. Its equivalent to fiberglass in this regard.
My preliminary list of potential midranges in post 486 is ranked from lowest to highest price. My personal favorite would be the NE149W and I kept it on the list. However, (1) it is the most expensive on the list, and (2) I think is difficult to obtain in Europe (I'm not sure if this is correct, and I do see it available on Aliexpress). While it is in the discussion, I would be surprised if that is the one we settle on.
Can you explain this in more detail?
Here is the SB12MNRX in a 0.08cf sealed enclosure with no HP filter in place. Fs is 62Hz per data sheet. Is this just about natural roll-off due to the enclosure (as shown) or do I need to add a filter?
I think 0,08cft is quite large. Traditional cheapskate solution would be aiming for a Qtc of 1.0 and use an appropriate C to get back to a crossover Q of 0,7. You’d have to test power limits though. A second order electrical highpass would give some more flexibility
Intuitively, one of the reasons for a 3-way is to have the larger woofer handle the lower mids.
If you’ve been following @DcibeL’s adventures in FSAF testing, almost all drivers benefit from a high pass.
This evidence for me moves it from maybe to there is absolutely clear sonic evidence for a high pass on a midrange.
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I saw some plastic bowls, and small trash cans at Walmart, that looked like they could be used to make a mid chamber..The bowls had decorative ribs that looked like they would add stiffness. I prefer a large mid chamber for myself, but for this design, I suppose 15L is out of the question.