@mtg90 mentioned this for the ds215 as well:
https://www.mtg-designs.com/diy-speaker-plans/flex-8/flex-8-ds
For the record, my original plans for this project had a driver budget of $120 per side, which is quite challenging for a 3-way. The drivers at the top of the list were:
Tweeter: Dayton ND25FW-4 waveguide tweeter ($22)
Mid: SB acoustics SB12PAC25 ($37)
Woofer: TBD (approximately $50)
I do believe that many of the woofers suggested in this thread would work well, and this driver combination could make a nice, inexpensive 3-way speaker. I have decided to double my driver budget, which I will talk about in a new thread.
Tweeter: Dayton ND25FW-4 waveguide tweeter ($22)
Mid: SB acoustics SB12PAC25 ($37)
Woofer: TBD (approximately $50)
I do believe that many of the woofers suggested in this thread would work well, and this driver combination could make a nice, inexpensive 3-way speaker. I have decided to double my driver budget, which I will talk about in a new thread.
😱
What?!
Blown the budget (again!?)
You’re not racing to the bottom, and not off shoring everything?
I look forward to your usual detailed documentation of this project.
What?!
Blown the budget (again!?)
You’re not racing to the bottom, and not off shoring everything?
I look forward to your usual detailed documentation of this project.
With that tweeter and mid and a $50-$60 woofer, you'd have a great value speaker.
Doubling the budget almost takes the fun out of it, because at $240 per side you have TONS of options.
That GRS 8 inch fits right on the money plus you can order everything at the same shop! 🙂
edit; Oh wait, Parts express doesn't do SB anymore?
In that case;
https://www.parts-express.com/SB-Acoustics-AA-D002-04-Paper-Cone-Mid-Woofer-4-ohm-299-754
Or rather just pic your favorite Dayton mid instead. 🙂
The new SIG120-4 for example 😉, is even a bit cheaper.
Well technically, we are still in the requirements definition phase, so I didn't blow the budget, I refined the spec 🙂 . It is only after the designer (me) formalizes the requirements with the customer (me) that we actually have a budget.
As you said, almost. Yes there are a lot of options. But to me it just did not make sense to make the driver budget so low when the electronics budget is somewhat fixed, and much higher.
I tried using the SB12PAC25 as mid range and even though the stated sensitivity is 87bd I found it had trouble keeping up with a 6 1/2 Audax. You might have better luck, I have a pair if you want them.
This is the actual woofer I have. https://www.parts-express.com/Dayto...ference-Paper-Woofer-8-Ohm-295-577?quantity=1 Mine is before the "improved" frequency response. It's crossed @ 2 kHz with a medium Q notch filter, no impedance correction. That's what tamed the honk (below 3 kHz) without sucking the dynamics out of the music, determined empirically.
The nasty midrange really limits its use in a two way. It was a little tricky to tame.
The nasty midrange really limits its use in a two way. It was a little tricky to tame.
I’d probably wait for these myself.
2” voice coils are pretty cool in a speaker that size/price. Low distortion too much like the rs225.
https://www.parts-express.com/Dayto...nature-Series-Woofer-4-Ohm-295-656?quantity=1
2” voice coils are pretty cool in a speaker that size/price. Low distortion too much like the rs225.
https://www.parts-express.com/Dayto...nature-Series-Woofer-4-Ohm-295-656?quantity=1
The Sig series is very impressive, has anybody measured them, I looked at the 6 1/2 spec sheet and it looks to good to be true.
Seriously, wouldn't be it an idea to form a group buy (Patreon style) to ship some things?
Just all tip in a few bucks.
Whatever one can miss, even if it's a dollar it adds up super quickly.
@wolf_teeth
Are you able to measure in a similar fashion to @HiFiCompass eg. 315mm and 20mm and selected voltages eg. 2.83V, +3/6/9/12dB so close approximations can be made with his large database?
If not, could you measure a known reference at the same time, so we have something to compare to?
Are you able to measure in a similar fashion to @HiFiCompass eg. 315mm and 20mm and selected voltages eg. 2.83V, +3/6/9/12dB so close approximations can be made with his large database?
If not, could you measure a known reference at the same time, so we have something to compare to?
looks on spec with Dayton data sheets.
Some commentary if I may- very smooooth frequency response. Who needs a fancy textreme or beryllium cone?
Just optimise the geometry and get the attach points (cone to surround, cone to voice coil) more right.
So yes, the FR is night and very workable. But not all is perfect. There’s an impedance blip around 400 Hz and around 3Khz. A zoomed impedance trace would show it clearer for people who aren’t pixel peepers- and its corresponds to minor the frequency response wiggle, which corresponds to the harmonic distortion plot. Around 400Hz - BOTH H2 and H3 have a wiggle, which usually indicates a resonance. So there’s something going on there.
I’d like to see it tested at higher Drive levels to see if it gets much worse. It could be a reflection from the magnet or basket which is hard to avoid.
Now compared to a paper cone this is absolutely heavenly frequency response, but compared to the optimised hard cones, it’s behind the SB 17 NBAC/CRC from 150Hz to 2KHz.
Aldo, PE’s published distortion graph
shows the typical rising H3, and H3> H2, due to use of from use of single aluminium demodulation ring:
It would be interesting to see what the sub 100Hz performance is, which is why I’m curious about the larger Sigs…
Some commentary if I may- very smooooth frequency response. Who needs a fancy textreme or beryllium cone?
Just optimise the geometry and get the attach points (cone to surround, cone to voice coil) more right.
So yes, the FR is night and very workable. But not all is perfect. There’s an impedance blip around 400 Hz and around 3Khz. A zoomed impedance trace would show it clearer for people who aren’t pixel peepers- and its corresponds to minor the frequency response wiggle, which corresponds to the harmonic distortion plot. Around 400Hz - BOTH H2 and H3 have a wiggle, which usually indicates a resonance. So there’s something going on there.
I’d like to see it tested at higher Drive levels to see if it gets much worse. It could be a reflection from the magnet or basket which is hard to avoid.
Now compared to a paper cone this is absolutely heavenly frequency response, but compared to the optimised hard cones, it’s behind the SB 17 NBAC/CRC from 150Hz to 2KHz.
Aldo, PE’s published distortion graph
shows the typical rising H3, and H3> H2, due to use of from use of single aluminium demodulation ring:
It would be interesting to see what the sub 100Hz performance is, which is why I’m curious about the larger Sigs…
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I'm not sure if that MCM wasn't the one that got redesigned, so whether the measurements are for old or new...?!. I may be wrong, but I was looking at an MCM and you could tell from the basket that they got redesigned recently.
The 6 inch only has 5mm xmax, so that's not gonna be great to begin with.
That rising 3rd order isn't great either unfortunately.
It almost makes you wonder if an inverted cone isn't contributing to that smooth freq resp? Although, that's probably a false correlation.
The most impressive thing, for me, is that they manage to dampen all the high hz resonances typical of hard cones. I wonder what's responsible for that? Perhaps the "Polyimide formers for improved mechanical damping smooth frequency response"
Yes I would have liked copper sleeve in the motor, or at least a (copper) shorting ring. It's not like it costs a lot of money when Tymphany can put it in all their drivers like the TC/TG9 etc...
If jim is using just a single 8" in an active speaker with LT, then Vd is what matters, and it looks like the Sig225 has about the same as the RS225-4.
Yes I would have liked copper sleeve in the motor, or at least a (copper) shorting ring. It's not like it costs a lot of money when Tymphany can put it in all their drivers like the TC/TG9 etc...
If jim is using just a single 8" in an active speaker with LT, then Vd is what matters, and it looks like the Sig225 has about the same as the RS225-4.
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