Budget Classic 3-way Discussion Thread

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#407
It makes sense, that's why I talked about the SLS-12 from the beginning in the other thread.

The 10" if staying sealed design makes even more sense now I have seen the sims with it as the cabinet will be littlier than with the SLS12 if sealed.

A vented asks way more try & error, so will cost more to design too, but if copying a free public known already to sound good in that dpt.

I have no idea if we should take the road of the vented design for people !
 
#408
diyiggy said:
All the 3" of above will miss some efficienty but if you have them in 4 ohms. T Gravsen shown those 3" with 8" cones were crosssed too low and then the mid was chosen a little bigger for the evo of his "little" 3 ways classic. 4" to 6.5" is certainly a good target. Certainly few exceptions as the Beta-8A talked above in the hand of a good filter designer (who I am not) as a 8" and the mid domes that are out for that project due to the prices.
Click to expand...
The Beta 8a has little xmax. Its actually around 2.5 mm peak one way. Eminence exaggerates this and in all sincerety, this is an extended range midbass. The mids are great with proper BSC, actually excellent, but it struggles down low unless running it ported.

There's another higher sensitivity 6" most people haven't heard about - the SB 6MW150D. Excellent in a ported box down to 60 hz and good past 3k with the right filter topology. It would do well as a mid crossed lower with a larger woofer ie. SB34 family, capable of a 200 hz 2nd order HP in a small sealed box. It would work with minimal baffle width thanks to sensitivity and xmax. It also can deal with a butt load of power.

Shouldn't overlook the Lavoce MAF061.50 cone mid. A bargain at under $90 and 94 dB/W sensitivity. Very clean, extended mids. Excellent with vocals, piano, acoustic instruments. Well behaved off axis. Basket is a little challenging to flush mount.
 
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#410
The SB34NRX-6 is likely the best sounding, most suitable woofer considering the cost. Its more sensitive, handles alot of power with minimal compression, goes low in a smaller sealed box and sounds as good as anything in the same price range. Crossed under 250 hz, you'd be hard pressed to hear the a difference from the NRXL or any of the larger Peerless woofers. Actually, there's very little difference between the 12".SS Revelator and the sealed box SB34 under 100 hz. The 34NRXL is actually on par with the SS Revalator, but its cheaper brother is very close. The NRXL sounds a bit more composed with complex midbass content.
 
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#411
So I tried to go through the 400 posts and summarize the status of the woofer selection.
Looking at some of the commercial 3-Way Classic designs, the JBL L100 looks very good from a size and dimensions perspective. It is approximately 2.5 cf (70L) and could be scaled up to 2.8 cf (80L) if needed. I would deduct 0.30-0.40 c.f. (8.5-11L) for the midrange enclosure, bracing, and port (if vented).

Here is the list. Please add drivers to the list if needed, and add comments - especially if you disagree with my assessment.

12-inch woofers:
  • SB Acoustics SB34NRX75-6: Excellent driver, F3 of ~40Hz sealed in target cabinet. In the US is slightly out of the target price range, but okay at the top of the price range in Europe.
  • Peerless SLS 830669: F3 a little higher than we wish in a sealed cabinet, but this is by far the least expensive driver we considered in US prices. Not as high a value in Europe, but it is still the lowest price driver considered. Given the design goal is a BUDGET speaker, this seems appropriate.
  • LaVoce SSF122.50L: Questionable TS parameters but models nicely in our target cabinet. Is anyone interested in this driver, other than me?
  • Peerless XXLS 830845: Models good in the target cabinet size. Less than SB34NRX75-6 in the US but MORE expensive in Europe. Given the SB34NRX is less expensive in Europe and not that much more expensive in the US, the SB34 seems to be the better choice.
  • Beyma 12BR70: Needs a cabinet much larger than the target size.
  • FaitalPRO FE330: Needs a cabinet much larger than the target size.
I would conclude that we proceed with two designs, one with the SB Acoustics SB34NRX75-6 and one with the Peerless SLS 830669. Midrange and tweeter to be determined, could be the same or different.

I am willing to construct a prototype with the Peerless and take measurements.
Is someone willing to do the same with the SB34NRX75-6?

Are we satisfied to proceed with those two 12-inch woofers OR do we want to consider 10-inch woofers?
 
#412
I think hard targets are needed to be set, because people are diverting away from the original goal all the time. Then people will be more keen to build it or not. I thought the original plan was a cheap classic monkey box design, but you all drive the price up and make the building divert from that classic monkey coffin deisgn with waveguides, dsp and so.

If we don't set that hard target (could be different than above) we will disuss this still next year and the public will not know what to expect, so it's hard to see if if fits them. So someone who is going to build it takes the lead and set the targets (won't be me), then people know what to expect and can engage in the build or not.

But i won't do that, i said it from the start, i'm already overloaded with projects. I can assist and advice, but that's it.
 
#413
12" sealed box woofer in 70L

If the 830669 is the is a good candidate;
Assuming 35cm wide baffle, baffle step compensation sensitivity is 89dB/2.83V (8 ohms), with reference to 100Hz.
2 pi F3, F6, F10- 48Hz, 39, 30 Hz
Max SPL @1m = 106dB (100Hz)

See simulation:

1740029271960.png


If there are more affordable woofers in 70L sealed (or bass reflex) let's see it.

re: pricing-
SB34NRX75-6

€220 -https://www.soundimports.eu/en/sb-acoustics-sb34nrx75-6.html
$220 - https://www.madisoundspeakerstore.com/approx-12-woofers/sb-acoustics-sb34nrx75-6-12-woofer/

830845 cheaper in EU and US:

€ 200
https://www.soundimports.eu/en/peerless-by-tymphany-xxls-p830845.html
$190
https://www.parts-express.com/Peerl...omex-Cone-Subwoofer-8-Ohm-264-1646?quantity=1

The XXLS 830845 is cleaner driver than the SB34RNX75-6.

The closest equivalents in term of harmonic distortion performance/IMD is the
SB34RNXL-8, or the RSS315HFA-8

Other comments-
It is wiser to focus on F6/F10, rather than trying to get the lowest F3.
 
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#415
waxx said:
I think hard targets are needed to be set, because people are diverting away from the original goal all the time. Then people will be more keen to build it or not. I thought the original plan was a cheap classic monkey box design, but you all drive the price up and make the building divert from that classic monkey coffin deisgn with waveguides, dsp and so.
Click to expand...

Don't confuse "cheap" with "budget". We can design a cheap, and crappy, 3-way for about $200 total in drivers. A maximum of $600 for drivers has been mentioned several times. My post #411 is meant to decide a woofer and make progress. It proposes TWO designs. One with a SB34NRX which with an appropriate choice of midrange and tweeter can come close to that maximum (at least in Europe where the SB34NRX is a little less expensive). The other would likely be less than $400 in drivers.

To make progress...directly address points in post #411 regarding choice of woofer to move forward to selecting other drivers.
 
#416
I'd advise to stick to the SLS budget version, regardless of woofer choice. I'd even suggest to offer a very cheap version
as well and increase the group of potentially interested builders. Anyway, it would be more fun and less risk involved.
With the right x/o filter, it might sound better than assumed.
 
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#417
A4eaudio said:
One of my biggest concerns right now - as mentioned several times - is that it is not clear who is going to build / design something. Most people want to use what they have on hand
Click to expand...
Ask yourself who you're (not) targeting with the project. Ask yourself what makes the project (un)attractive to these people.
This will help you to lead the process towards determining the design goals.
 
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#418
Perhaps part of the challenge is that people who have skin in the game (ie. would be builders) find it hard to get excited about $30 drivers.

And who could blame them when some us are measuring the highest performing drivers with laboratory standard microphones, perhaps inadvertently giving the impression that one needs the best parts to build a nice loudspeaker.

Not so.

Though I understand the desire to have a good budget on drivers, spending $200 for 6 drivers certainly doesn't have to mean that it will be a terrible speaker.

Yes a sloppy design can give a crappy 3 way, but one could also do a good 3-way for $200 of drivers. It’s just harder because more compromises need to be made.

There are at least a few people among us whom I could give the $210 drivers that I nominated in the post that discussed drivers with well behaved frequency and impedance responses , and the end result would be better that what first time DIYers who had purchased a handful of Scan-Speak or (insert their most desired model here)

Experienced designers know how to read spec sheets carefully before they dive in, and know how to get the most out of their cabinets, get the most out of the drivers and choose crossover parts wisely.
 
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#419
^""Perhaps part of the challenge is that people who have skin in the game (ie. would be builders) find it hard to get excited about $30 drivers"

But is this really an issue in a thread dedicated to a budget build, which started from a thread that was deemed to be getting too expensive?
 
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