In a fully active design acoustic centers don't really matter, since that can be compensated for.
In practice this is a problem that especially for a 4 inch + tweeter, I find a bit excessive. In practice this can be compensated for enough by choosing the right filters.
In an hybrid system there are some tricks.
In practice this is a problem that especially for a 4 inch + tweeter, I find a bit excessive. In practice this can be compensated for enough by choosing the right filters.
In an hybrid system there are some tricks.
True... but in this particular case the mid and tweeter are on a single amp/DSP channel with a passive network between them. So I do have to be cognizant of the path length difference between the two drivers, and the passive network will need to manage the phase.
To be fair, I never had major issues in passives filters (which are the same as IIR filters).
There are other ways to compensate, for example giving the tweeter a 3rd order filter vs a 2nd order filter for the woofer.
(which will introduce additional group delay).
This is just one example, the point is, you don't always have to fix that path length.
What DSP are you gonna use?
If you use something like Sigma Studio, there are ways to still delay the part above a certain frequency.
This is not ideal (compared to a real delay), but does help sometimes.
Using a FIR phase compensation technically works, but I wouldn't recommend it since it will delay the entire filter.
Anyway, for me this would definitely not be a shower stopper.
Especially because the Dayton ND25FW-4 is already quite deep to begin with.
So i doubt that the center compared to the 4 inch will be so far off.
Worst case you can always use a passive "delay" filter for just the tweeter.
Which will work, especially with all those other options available.
(here a quick example). You can stack those as well to introduce more "delay".
With the passive XO, consider LR2 if your mid-driver and tweeter can handle it. This may require you shifting the crossover frequency slightly higher to 2.5K or beyond, yet you still maintain get a good directivity match and power response / predicted in-room response. Mismatched acoustics centers can be dealt with using asymmetric slopes or a a ladder delay/ all pass network or slanted baffle. B) adds more passive crossover parts which adds to cost, which is counterproductive if you're trying to keep costs down. Whereas a slanted baffle doesn't make construction any easier.
@5th element's work on home grown coaxial coincides (pun not intended) with @augerpro's findings -> choose a waveguide similar in dimensions to your midrange driver. Geometry matters and when things are easier from the start, it simplifies passive XO work... so there's really no reason to NOT choose the 4" waveguide...
@5th element's work on home grown coaxial coincides (pun not intended) with @augerpro's findings -> choose a waveguide similar in dimensions to your midrange driver. Geometry matters and when things are easier from the start, it simplifies passive XO work... so there's really no reason to NOT choose the 4" waveguide...
MiniDSP 2x4HD. My thoughts on electronics
https://www.diyaudio.com/community/threads/compact-low-cost-active-3-way-speaker.402812/post-7441164
Absolutely true.
Waveguide is not a requirement, but it is an option that I am exploring. Both of the idealized simulations in post 135 look acceptable, but different. https://www.diyaudio.com/community/threads/compact-low-cost-active-3-way-speaker.402812/post-7449284
I have built speakers with directivity performance similar to both. When the directivity index above 1k is in the 7+ dB range, the soundstage and imaging is different from a similar speaker whose directivity index above 1k is about 5 dB. So it is a choice I will have to make.
Regarding midrange drivers: I have been pouring through as much online information as I can to get objective data on 4 inch-5.5 inch midrange drivers in the $40 - $80 range. My criteria are (1) 2nd Harmonic Distortion (HD2) below 1% from 300 - 2.5k at 93 dB SPL. (2) HD3 below 0.5%, but lower is better, over the same range. (3) smooth frequency response over the same range. (4) Absence of resonance / stored energy over the same range.
My short list is
| Zaph Audio ZA14W08 | $ 60 |
| TangBand W4-1337SD | $ 80 |
| SB Acoustics SB15NBAC30-4 | $ 81 |
| Dayton Audio RS125-4 | $ 45 |
Both the TB and SBA drivers have higher performance than the Zaph and the Dayton. I have used the SBA driver and found it to be very good, but I would like to get experience with other drivers, so at this price range I would lean towards the Tang Band.
https://www.parts-express.com/Tang-Band-W4-1337SDF-4-Titanium-Full-Range-Speaker-264-916?quantity=1
If I choose a non-waveguide option, my current driver list would be the TangBand W4-1337SD and the SB29SDAC, for a combined cost of $130. Thanks to wolf_teeth for making me aware of the Tang Band options !
If I choose a waveguide option, I would use either the Zaph or the Dayton driver, along with an SB26ADC in an Augerpro waveguide. Combined driver cost is $130 if I use the Zaph.
I might purchase both the Zaph and the Dayton RS125 to evaluate them...
j.
My experience with TangBand is so extremely all over the place.
They have some nice stuff, but the quality control can be such a hit or miss sometimes.
Their datasheets are sometimes totally different than the actual performance.
But most of all, I still feel salty after they just literally multiplied their prices by two a couple of years ago.
I personally don't like to advice it for professional purposes, but I guess for a DIY project it's fine.
I think you can make something great with any of those drivers to be perfectly honest.
Just a few things about directivity.
You can probably get away just fine without any waveguide at all.
This would probably will give a much wider soundstage I think.
I personally would cross a tweeter as low as possible, as long as the THD and directivity behaves well.
With a 5 inch mid, you can get a little louder (or less distortion), but also will have an higher directivity.
They have some nice stuff, but the quality control can be such a hit or miss sometimes.
Their datasheets are sometimes totally different than the actual performance.
But most of all, I still feel salty after they just literally multiplied their prices by two a couple of years ago.
I personally don't like to advice it for professional purposes, but I guess for a DIY project it's fine.
I think you can make something great with any of those drivers to be perfectly honest.
Just a few things about directivity.
You can probably get away just fine without any waveguide at all.
This would probably will give a much wider soundstage I think.
I personally would cross a tweeter as low as possible, as long as the THD and directivity behaves well.
With a 5 inch mid, you can get a little louder (or less distortion), but also will have an higher directivity.
Curt Campbell and Jim Holtz used the W4-1337SD in multiple designs, including Statements, Statement Monitor, Mini Statements and Statement Centre channel. Interesting they also use the RS225-8 extensively.
He later switched to the NE123W and NE149W for the Statement II and Micro Statements.
Designs are over at
www.speakerdesignworks.com
Statement II announcement thread- (and built pictures by yours truly)
https://www.htguide.com/forum/forum/mission-possible-diy/40770-statements-ii-a-musical-evolution
Interestingly, due to the NLA status of the Peerless, he’s switched to the SB15CAC for later designs
Travellers announcement thread:
https://www.htguide.com/forum/prime...ished/43207-the-travelers-new-year-new-design
Anthology II thread:
https://www.diyaudio.com/community/threads/anthology-ii.401386/
I think it’s worth asking @jholtz his opinion of this W4-1337 driver. Particularly if the price has doubled. He had extensive experience with both the W4-1337, and the SB15CRC, which you have had.
He later switched to the NE123W and NE149W for the Statement II and Micro Statements.
Designs are over at
www.speakerdesignworks.com
Statement II announcement thread- (and built pictures by yours truly)
https://www.htguide.com/forum/forum/mission-possible-diy/40770-statements-ii-a-musical-evolution
Interestingly, due to the NLA status of the Peerless, he’s switched to the SB15CAC for later designs
Travellers announcement thread:
https://www.htguide.com/forum/prime...ished/43207-the-travelers-new-year-new-design
Anthology II thread:
https://www.diyaudio.com/community/threads/anthology-ii.401386/
I think it’s worth asking @jholtz his opinion of this W4-1337 driver. Particularly if the price has doubled. He had extensive experience with both the W4-1337, and the SB15CRC, which you have had.
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This is a distortion plot from the W4-1137SA variant @ 90dB (so that is NOT the ferrit SDF variant), tested quite a while a go in a german magazine.
Based on this graph, I wouldn't call it that great.
Could be that the newer SDF variant is better?
Personally also not fan on the looks (especially for that price!)
Based on this graph, I wouldn't call it that great.
Could be that the newer SDF variant is better?
Personally also not fan on the looks (especially for that price!)
https://hificompass.com/ru/speakers/measurements/tb-speakers/tangband-w4-1337sd
HiFiCompass shows pretty good performance for the W4-1337SD, basically very similar in performance to the SB15NBAC
HiFiCompass shows pretty good performance for the W4-1337SD, basically very similar in performance to the SB15NBAC
Do you mean the SB15 (5 inch) or SB12 (4 inch) ?
Because compared to the 5 inch, I don't agree
Also keep in mind that at hificompass, we are comparing voltage levels, NOT sound pressure levels.
So a 4 inch is gonna do less SPL at the same voltage in most cases.
I would find it extremely odd if a 4 inch driver like this would perform so close to one of the better 5 inch mid woofers out there, while having a lot less surface area.
edit: when we look at 90dB, the graph looks a lot like the one from hobby hifi if you recalculate the values to % THD.
Here the 1337 @ roughly 94dB
And the SB15NBAC ar roughly 94dB
Because compared to the 5 inch, I don't agree
Also keep in mind that at hificompass, we are comparing voltage levels, NOT sound pressure levels.
So a 4 inch is gonna do less SPL at the same voltage in most cases.
I would find it extremely odd if a 4 inch driver like this would perform so close to one of the better 5 inch mid woofers out there, while having a lot less surface area.
edit: when we look at 90dB, the graph looks a lot like the one from hobby hifi if you recalculate the values to % THD.
Here the 1337 @ roughly 94dB
And the SB15NBAC ar roughly 94dB
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Is that in comparison to other aluminum cone drivers? Titanium should not oxidize, so if it oxidizes easily, then I am not sure what is going on.
I should have been more clear when I said "basically very similar in performance to the SB15NBAC"... I was looking at both of them at 4 V, where they both produce approximately 90 - 92 dB, and I meant that both meet my HD criteria. Yes the SB15NBAC is superior. But I am not sure it is meaningfully superior.
I concur with @b_force -
It’s best to match the SPL over the intended range of usage. And ideally one would shape the FR as desired and then do distortion testing; but that’s not always possible.
I compare at 86dB, 96dB, and when permitting 106dB (but only the biggest/best drivers can tolerate that)
So in the absence of that shaped FR comparisons, I compare at
2 levels- 2.83V (1W 8 ohms) and 8.95V (10W 8 ohms). For high sensitivity eg . 95+ dB sensitivity drivers I also look at 0.283V (0.1W; -10dB from characteristic sensitivity)
I consider anything -6dB significant. Although I don’t have evidence for that. Two drivers in an MTM gives +6dB, which is why I use this minimum criteria. 2-3 dB and it’s generally a wash, IME.
If you are a (free) member of Hificompass you get to click and compare 3 difference drivers; very handy and much recommended.
Email/Login function require to access this pixel peeping function.
It’s best to match the SPL over the intended range of usage. And ideally one would shape the FR as desired and then do distortion testing; but that’s not always possible.
I compare at 86dB, 96dB, and when permitting 106dB (but only the biggest/best drivers can tolerate that)
So in the absence of that shaped FR comparisons, I compare at
2 levels- 2.83V (1W 8 ohms) and 8.95V (10W 8 ohms). For high sensitivity eg . 95+ dB sensitivity drivers I also look at 0.283V (0.1W; -10dB from characteristic sensitivity)
I consider anything -6dB significant. Although I don’t have evidence for that. Two drivers in an MTM gives +6dB, which is why I use this minimum criteria. 2-3 dB and it’s generally a wash, IME.
If you are a (free) member of Hificompass you get to click and compare 3 difference drivers; very handy and much recommended.
Email/Login function require to access this pixel peeping function.
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Hi Jim, for whatever it is worth, I have been trying to build a similar system using a single 8" woofer but have found the single 8" woofer just does not make the cut, no matter how good the mid and tweeter combination is. I am still trying and will post if somehow I am able to make it. For now, the closest I have come to hearing musically pleasing speakers at reasonable budgets is with a 10 inch woofer as you suggest later in this thread. I did make a variation of Paul Carmody's design using a 10" peerless SLS woofer, plus either a matched peerless 6.5" sds/hds woofer plus their D27TG 1" silk dome tweeter, and the music quality is good. The good part is the upper box can be used separately as a compact two way bookshelf, and with the subwoofer below can be added to make a more complete system for a larger room. With a bit of a creative usage of binding posts at the back I can use these both as passive as also active.
Then I also made a 3 way system using 2*6.5" hds/sds woofers from peerless (using both in separate pairs) and a 5.5" hds/sds woofer for the mid combined with the same D27TG tweeter. The cabinet is high at 50 inches so that defeats your purpose for a smaller cabinet, but since the footprint is low at 10" I thought this might be a bit relevant particularly if the compact system requires a stand. Again, I have used this both as active and passive and I am rather pleased with the sound quality, and they do cover the entire spectrum and go low to the around 35hz sealed, and below 30hz vented.
I can post the crossover schematic and response if someone is interested. I have gone through your entire thread and you seem a quite accomplished designer so pardon if I have butted in irrelevantly.
Thank you to @wolf_teeth , @b_force , @tktran303 for your thoughts on the TB W4-1337SD. The fragility of the cone concerns me. I was hoping to find an $80 driver with the same or better performance as the SB15NBAC. I used the very similar SB15CAC driver in my tower system last year, and at that time this driver seemed to have the best performance/price ratio. I was rather looking forward to working with a completely different set of drivers... maybe at this price point, the SB is the best choice?