Hi all,
I am thinking of embarking on a 3-way speaker design, ordinary boxed speakers nothing fancy, but with the following points in mind:
Which 12" bass driver should I use? The challenge here is to get the sealed bass extension which I'm looking for, plus work well as a woofer, not just a sub, till maybe 300Hz. I'm willing to work with a 4th order crossover on the LP of the woofer if I need to, if I have nasty cone break-up. But it would be nice if I could stick to lower order filters. Not a must.
If I were willing to accept a 10" woofer, there may be Dayton RS270P paper cone drivers, or this one from SB Acoustics or a few Seas paper cone ones, which may fit the bill. But I was really hoping to use a 12".
Will the NE315W-08 work? There are very few mentions of any FM having used the NE315 on DIYaudio -- I found just two projects, I think.
I need to try to keep things 8 Ohm, so that I land up with a slightly easier load on the amp. (I don't have a problem with a 4 Ohm tweeter, because I usually land up having to cut down its output a bit anyway.) My mid is an 8 Ohm too.
Why do they call the NE315W-8 a "subwoofer", while the NE315W-04 is just called a "woofer", on Parts Express? What am I missing? Will the NE315W-08 be a good choice? What other drivers would you rather suggest? 300-dollar drivers are out of my budget, sorry.
I listen to all types of music, includng soft vocals, jazz, 70s and 80s rock, and classical. I want a speaker which doesn't have any "type of music".
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Update 1 Aug 2019
Created a spreadsheet and shared it on Google Drive
Will keep updating this spreadsheet whenever any of you give me some pointers to some drivers I like.
For each driver, I am tracking two parameters which seem to make sense to me for selecting a woofer for one of my projects: the sensitivity and the moving mass (Mms). The sensitivity needs to match with other drivers for obvious reasons, specially if I'm doing a passive design, and the moving mass is a nice check on the construction of the woofer -- typically the subwoofers with their super-low Fs have high moving mass, and therefore may be sluggish in reproducing bass details?
I am thinking of embarking on a 3-way speaker design, ordinary boxed speakers nothing fancy, but with the following points in mind:
- I want to do a 3-way with a passive crossover, having done the Darbari with an active xo and learned a lot
- I want a 12" bass driver, maybe crossed over at 200-300Hz? Still undecided about the driver and Fc
- The mid driver has been decided: it's the SB Satori MR13 midrange. Unlike the Darbari, where I used a 6" midbass doing midrange duty, this is a true mid, so I don't think I want to push it down to 100Hz.
- Tweeter is undecided, but will be something from SB Acoustics. I don't see the tweeter choice as being critical in this design.
- I want sealed bass, with a Qtc between 0.6 and 0.7.
- I want the F10 of the sealed bass unit to reach somewhere in the 20s Hz range. Don't want the F10 to stop at 30Hz or higher.
Which 12" bass driver should I use? The challenge here is to get the sealed bass extension which I'm looking for, plus work well as a woofer, not just a sub, till maybe 300Hz. I'm willing to work with a 4th order crossover on the LP of the woofer if I need to, if I have nasty cone break-up. But it would be nice if I could stick to lower order filters. Not a must.
If I were willing to accept a 10" woofer, there may be Dayton RS270P paper cone drivers, or this one from SB Acoustics or a few Seas paper cone ones, which may fit the bill. But I was really hoping to use a 12".
Will the NE315W-08 work? There are very few mentions of any FM having used the NE315 on DIYaudio -- I found just two projects, I think.
I need to try to keep things 8 Ohm, so that I land up with a slightly easier load on the amp. (I don't have a problem with a 4 Ohm tweeter, because I usually land up having to cut down its output a bit anyway.) My mid is an 8 Ohm too.
Why do they call the NE315W-8 a "subwoofer", while the NE315W-04 is just called a "woofer", on Parts Express? What am I missing? Will the NE315W-08 be a good choice? What other drivers would you rather suggest? 300-dollar drivers are out of my budget, sorry.
I listen to all types of music, includng soft vocals, jazz, 70s and 80s rock, and classical. I want a speaker which doesn't have any "type of music".
----------------------------------------------------------
Update 1 Aug 2019
Created a spreadsheet and shared it on Google Drive
Will keep updating this spreadsheet whenever any of you give me some pointers to some drivers I like.
For each driver, I am tracking two parameters which seem to make sense to me for selecting a woofer for one of my projects: the sensitivity and the moving mass (Mms). The sensitivity needs to match with other drivers for obvious reasons, specially if I'm doing a passive design, and the moving mass is a nice check on the construction of the woofer -- typically the subwoofers with their super-low Fs have high moving mass, and therefore may be sluggish in reproducing bass details?
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On the company's site both the NE315W-04 and NE315W-08 are called subwoofers.
If sensitivity is high enough for you, i think these are good to 300Hz or even higher, has low distortion and smooth response up to 7-800Hz. But how it sounds up to that high, that's another question.
Transducers Archive - Tymphany
If sensitivity is high enough for you, i think these are good to 300Hz or even higher, has low distortion and smooth response up to 7-800Hz. But how it sounds up to that high, that's another question.
Transducers Archive - Tymphany
Thanks. 🙂
The matter of sensitivity has also been on my mind. It seems that most of the drivers which have good bass extension have heavier moving mass and therefore are able to reach so low, but therefore they also have lower sensitivity. I will look around a bit more and see if I can find any other drivers which are all these and also more sensitive.
The matter of sensitivity has also been on my mind. It seems that most of the drivers which have good bass extension have heavier moving mass and therefore are able to reach so low, but therefore they also have lower sensitivity. I will look around a bit more and see if I can find any other drivers which are all these and also more sensitive.
If you want bass extension and high sensitivity, expect also high/huge volume requirement. You can only have 2 out of these 3 properties: bass extension, high sensitivity, low vas (that is pretty evident in the T/S formulas). In fact many if not all subs have low sensitivity because they are designed with low vas.
Ralf
Ralf
Actually small enclosure size comes second in my list. I first want decently clean SPL curve and good bass extension in a sealed box with Q=0.6 or so. Even this seems not all that easy to get.
In fact, even if I ignore box size, I seem to find that bass extension conflicts with high sensitivity, at any box size. All the subwoofers I am seeing are low sensitivity, and all the high sensitivity drivers I am seeing roll off quite high. They may be good candidates for active equalisation but in passive mode, they don't extend deep by themselves.
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Have you looked into a tuba or folded horn sub box ? Very very high sensitivity and SPL with clean sound
No, I've never gotten interested in horns. I'm told horns can be amazingly sensitive.
Bass from well designed sealed box woofers sounds better than from ported box designs. The T/S parameters for the SB_Acoustics SB34NRX75-6 model -F3 = 37Hz in a sealed 3.5 cuft volume. The SB34NRX75-6 has a high Le= 1.8mH, which favors a low crossover frequency. Anyone building a passive crossover can utilize the Le=1.8mH to obtain a steeper acoustic slope with just LR2 passive parts.
The NE315-08 appears to work well in a 3ft^3 (85 liters).
50 watts gives you about 108 dB passband, with an F10 about 21-22 Hz.
F3 about 43 Hz, F6 about 30 Hz
Xmax is never exceeded. Box Qts = .607
Modeling for 100 watts shows xmax exceeded at about 25 Hz.
Looks very good to me, and I"m planning on a similar 3 way design next year.
Hope this helps.
50 watts gives you about 108 dB passband, with an F10 about 21-22 Hz.
F3 about 43 Hz, F6 about 30 Hz
Xmax is never exceeded. Box Qts = .607
Modeling for 100 watts shows xmax exceeded at about 25 Hz.
Looks very good to me, and I"m planning on a similar 3 way design next year.
Hope this helps.
^except it's not as sensitive as what he wants.. (..and remember you are also looking at 4/6 db of baffle-step loss.)
-pretty much what he want's (in total) does NOT exist. ie. a "futile thread".
-pretty much what he want's (in total) does NOT exist. ie. a "futile thread".
I understand. I think most of us hobbyists have unreasonable objectives at times.
Reality teaches us different!
So, I decided to look around on Parts Express and Madisound for woofers for my 3-way, with roughly these characteristics:
I have attached my list, with the drivers I could find. All this is modelled on Unibox. The Vb is the box volume at Q = 0.6, the F3 is the -3dB frequency at that volume, and the F10 is the -10dB frequency at that volume, read off the Unibox graph. In the odd cases where the box volume has gone into the Ridiculous Zone, I've also done another reading with Q = 0.7 to see whether there's a remote chance of using the driver with a higher Q.
It's interesting that I found less 12" drivers than 10" which can deliver to my requirements. There are a few border-line cases,though, which have an F10 of 30Hz or 31Hz. I wonder whether I can hear any difference between, say, a 25Hz and a 30Hz in side-by-side comparisons in the same room, all else being equal. And the Eton Orchestra drivers shore look purrty. The SB34NRX75-6 has amazing bass extension and a decent SPL curve, but its box size is huge -- the only way I can hope to use it is at a Q of 0.7, which I was hoping to not go to.
I created this spreadsheet because I find that I can't easily compare woofers for sealed use unless I do this -- Unibox does not give me any easy way to compare the numbers of multiple drivers side by side for a given Q.
- price: below $300 per driver
- 12", with 10" as a compromise. (I am toying with the idea of even doing 2 10" instead of a 12", as an alternative. Maybe. We'll see...)
- must have an SPL curve which has a reasonable chance of integrating to a mid at 300Hz
- preferably 8 Ohm
- must give me an F10 in the 20s Hz with a sealed box with Q = 0.6
I have attached my list, with the drivers I could find. All this is modelled on Unibox. The Vb is the box volume at Q = 0.6, the F3 is the -3dB frequency at that volume, and the F10 is the -10dB frequency at that volume, read off the Unibox graph. In the odd cases where the box volume has gone into the Ridiculous Zone, I've also done another reading with Q = 0.7 to see whether there's a remote chance of using the driver with a higher Q.
It's interesting that I found less 12" drivers than 10" which can deliver to my requirements. There are a few border-line cases,though, which have an F10 of 30Hz or 31Hz. I wonder whether I can hear any difference between, say, a 25Hz and a 30Hz in side-by-side comparisons in the same room, all else being equal. And the Eton Orchestra drivers shore look purrty. The SB34NRX75-6 has amazing bass extension and a decent SPL curve, but its box size is huge -- the only way I can hope to use it is at a Q of 0.7, which I was hoping to not go to.
I created this spreadsheet because I find that I can't easily compare woofers for sealed use unless I do this -- Unibox does not give me any easy way to compare the numbers of multiple drivers side by side for a given Q.
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Thanks a lot. This is really helpful. My spreadsheet throws up a few other interesting candidates, worth modelling and taking a look at. But the NE315W does remain one of the best bets.
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By this yardstick, most DIY threads for projects which push the performance envelope are futile. 🙂 However, by starting on such a path, we get to see the optional compromises clearly, and then we pick the compromises which we can live with. I can live with lower sensitivity, for instance. Sensitivity was never very high on my list -- I just didn't want to go down to the really low-sensitivity drivers like 82dB or 84dB, that's all.
When people say , your ideas are unrealistic
Well , those words drive real men to do the unrealistic and impossible
If you can think it, it can be done
Well , those words drive real men to do the unrealistic and impossible
If you can think it, it can be done
..altering your requirements - that's something altogether different. ..and yup, with a bit different constraints you can achieve some of the things on your wish list.
I'd still do it (most of your other requirements) with the right bass reflex design (low tuning freq.) and the right woofer (low Qts. and high sensitivity) ..even if it required a couple of long vents. (..targeting about 89 db in relation to your midrange choice.)
LaVoce WAN123.00 12" Neodymium Woofer 8 Ohm
-around 2 cubic feet with a couple of long vents (..50 liters + tuning freq. of 24 Hz).
I'd still do it (most of your other requirements) with the right bass reflex design (low tuning freq.) and the right woofer (low Qts. and high sensitivity) ..even if it required a couple of long vents. (..targeting about 89 db in relation to your midrange choice.)
LaVoce WAN123.00 12" Neodymium Woofer 8 Ohm
-around 2 cubic feet with a couple of long vents (..50 liters + tuning freq. of 24 Hz).
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Actually, I think my goal is not difficult to achieve if I just permit myself to switch from sealed box with Q=0.6 to bass reflex. But that's a switch I'm not willing to do. 🙂
In fact, I think this entire journey to search for the right woofer started from that starting point: can I go sealed box bass with a 12" woofer for my 3-way, which will give me what I consider good in-room bass extension? The other points are just secondary constraints.
I had seen the LaVoce woofer you've referred to. The sensitivity is to die for -- this is the kind of sensitivity I dream about when I think of building a full-range passive speaker for a SET amp. But the Fs is too high for my requirements.
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Yes, but WHY aren't you willing to?
What started that "journey" to a sealed design? Is it just low freq. extension? If it is, have you modeled that example I gave?
BTW, you can use a compound-loaded driver to just about halve volume requirements for a sealed design. You do of course take a "hit" in efficiency. It does however violate your lower cost requirement (because it's two drivers vs one).
Hoffman's Iron Law isn't very accommodating.
What started that "journey" to a sealed design? Is it just low freq. extension? If it is, have you modeled that example I gave?
BTW, you can use a compound-loaded driver to just about halve volume requirements for a sealed design. You do of course take a "hit" in efficiency. It does however violate your lower cost requirement (because it's two drivers vs one).
Hoffman's Iron Law isn't very accommodating.
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I built my last speaker with sealed bass, and it's so different from any bass I've heard before that I want to try it further. In the meantime I've heard some very expensive 3-way studio monitors with TL bass, and it wasn't attractive. All my past experience has been with ported bass.
-and do you think I was suggesting a design that sounded like a "bass reflex"?
IF you model it, I think you'll find that it's pretty much a sealed design down to about *30 Hz. Plus, it's with a driver that has a much lower Qe/stonger motor - meaning the result will be much more "dynamic" than the sealed designs you've listened to.
*and you aren't going to hear the effects of massive group delay below that, nor do most recordings have a lot of infrasonic signal.
Other than the port-length issue, you are just limited by the excursion of this driver in what is effectively a sealed driver design down to 30 Hz with most recordings. Meaning spl will be limited without lower freq. compression (signal dependent).
Do NOT think of this design with respect to a standard bass-reflex alignment: it's NOT that at all. 😉
Note: to get the very best from this (or any lower freq. system - sealed included) requires an LCR filter for the in-box resonance. (..or an amplifier with a lot of current-reserve/massive power supply.)
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