I'm in search of a decent PA/hifi type 18" LF/sub driver for a vented 160L enclosure aiming for -3dB @ low 30s. It would be nice to have 95+ dB sensitivity at an acceptable xmax to achieve at least 115dB down to F3 and possibly good F10.
Budget is up to $400-ish and available here in the US. Been looking at the B&C 18TBW100 and 18TBX100 as possible options. Neo would be nice but a ferrite motor wouldn't be out of the question. Already tried the 18NW100 but its specs weren't as advertised.
I've looked at the so called 18" Marty Cube design, which is roughly what I wanted but I'm open to anything comparable. I prefer vented over the popular horn loaded TL for more accurate, tighter low end. A larger vented box is a good compromise IMO.
Please reply here with any suggestions in line with my preferences and goals.
Budget is up to $400-ish and available here in the US. Been looking at the B&C 18TBW100 and 18TBX100 as possible options. Neo would be nice but a ferrite motor wouldn't be out of the question. Already tried the 18NW100 but its specs weren't as advertised.
I've looked at the so called 18" Marty Cube design, which is roughly what I wanted but I'm open to anything comparable. I prefer vented over the popular horn loaded TL for more accurate, tighter low end. A larger vented box is a good compromise IMO.
Please reply here with any suggestions in line with my preferences and goals.
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18 Sound 18NLS4000 could be good for this. But you will need a way bigger port than that in the Marty design. You could use a resistive vent cabinet (that will be larger, something like a 250L) to make the vent short enough to fit. For that your vent must be 1:10 slot format (somethinglike 60cm wide and 6 cm high and 33cm deep). This is a very rough calculation for this. Sim and finetune if you go that direction.
The SB Audience NERO 18SW1900D looks like a fit other than the DCR is 5 ohms not 3.5. 17mm Xmax and matches your box parameters.
https://www.sbaudience.com/index.php/products/subwoofers/nero-18sw1900d/
https://www.sbaudience.com/index.php/products/subwoofers/nero-18sw1900d/
@perrymarshall That's a brute of a driver. I wanted 4 ohms due to maxing out available amp power. I have a QSC GX8D available for the task which will do about 1200W a side, but it will likely be overkill for hifi use.
I also considered a 2 x 15" design with 8 ohm drivers, widening the field of choices.
My concern is enclosure size. I wanted to stick with 160L mainly due to the available format of wood to build it. One sheet of 60 x 60 cm birch ply would be able to make up the basic sides in a single layer, but a double wall 1.5" (3/4" per layer) box would be better, mostly for heavier ferrite motors.
Luckily I still have some Baltic birch stashed for this build, as its so stupid hard to source now. I would have opted for some other type of plywood instead and steered clear of MDF due to weight and finish options.
My concern is enclosure size. I wanted to stick with 160L mainly due to the available format of wood to build it. One sheet of 60 x 60 cm birch ply would be able to make up the basic sides in a single layer, but a double wall 1.5" (3/4" per layer) box would be better, mostly for heavier ferrite motors.
Luckily I still have some Baltic birch stashed for this build, as its so stupid hard to source now. I would have opted for some other type of plywood instead and steered clear of MDF due to weight and finish options.
Hey. If you think about 18TBX100, I somewhat wonder why 18NW100 doesn´t work out for you. I had these drivers, and in my book these are just like 18TBX100, just little better and stronger motor. I run them hot, and they did not disappoint, and there is no way they can provide less performance than the TBX for anything ordinary except for outright damaging abuse. So That conclusion about this driver does not right to me. What´s wrong with em?
18TBW100 is an evolution from these and from TBX, and these can do a lot. I highly recommend these. As mentioned, the SB Audience Nero driver looks yummy, and might be in some ways even better. It´s a beast. Though, if the right impedance model is not available, it might be a wash.
160l is good for 18TBW100.
18TBW100 is an evolution from these and from TBX, and these can do a lot. I highly recommend these. As mentioned, the SB Audience Nero driver looks yummy, and might be in some ways even better. It´s a beast. Though, if the right impedance model is not available, it might be a wash.
160l is good for 18TBW100.
@Crashpc How old is your 18NW100? Is it 4 or 8 ohm? I suspect B&C made a running change in it over the years. The Fs on mine wasn't anywhere near spec and it started to complain way before it should have excursion wise.
The 18TBW100 is a much better looking driver on paper. It wasn't available in a neo version, which is why I originally overlooked it. Now I'm leaning towards it just from the physical properties alone. The basket is also completely different, being more of a larger frame driver where it counts, especially at the suspension. What Fs does your 18TBW100 measure at cold?
The 18TBW100 is a much better looking driver on paper. It wasn't available in a neo version, which is why I originally overlooked it. Now I'm leaning towards it just from the physical properties alone. The basket is also completely different, being more of a larger frame driver where it counts, especially at the suspension. What Fs does your 18TBW100 measure at cold?
That woofer is certainly capable of a lot of cone excursion, and its maximum SPL capability is very high.
The following simulation is for the NERO-18SW1900D in a 160-litre enclosure detuned to 26Hz. To compensate, I've added a 2nd-order high-pass peaking filter set to f0=27Hz with Q=1.60, which boosts by about 4.5dB at 30Hz or so, as well as controlling driver excursion below the vent tuning frequency. The computed response simulated in VituixCAD is shown below. With a nominal 115W re 8ohms of input power, we obtain 115dB SPL at 30Hz, which meets the design target. Here at 30Hz the response is only −1dB relative to the passband, which is at 116dB for this input power. The f3 is 26.7Hz, which also comfortably exceeds the design target of being −3dB in the low-30s frequency-wise, and f6=24.1Hz, which which is relatively low. The driver displacement at this power level is a bit under 1/2 of Xmax, so there is quite a bit of displacement in reserve for short-term peaks being reproduced linearly.
If we forego the use of the peaking filter, we can still get very good low-frequency extension. The VituixCAD simulation obtained when the vented enclosure is tuned to 34Hz is shown below. Here we have obtained f3=34.6Hz, and f6=30Hz. The response is −1dB at about 40Hz relative to the passband. This response isn't as extended as the previous filter-assisted one, which was −1dB at 30Hz, some 10Hz lower.
If running at very high power levels, it might be prudent to control cone excursion below 30Hz. This can be done by adding a 2nd-order Butterworth high-pass filter. Its cut-off frequency could be set to 16Hz if only moderate control was needed, or 20Hz, or even 24Hz, if stronger control was thought to be necessary. The appropriate choice would depend on whether or not there was going to be lots of signal content around or below 20Hz.
If the NERO-18SW1900D driver is placed in a closed-box 160-litre enclosure instead of a vented-box enclosure, it is possible to achieve the following response. Here a 4th-order Linkwitz–Riley low-pass filter has been applied, as its rolling-off frequency response interacts heavily with the increasing output of the sealed system when the frequency is increasing, and therefore needs to be accounted for. The f3=25.2Hz, which is quite good, but the maximum SPL is only 114dB when the input power is 240W re 8ohms, and Xmax is reached at 26.7Hz at this power level. The peak power input is almost 400W.
The NERO-18SW1900D driver has fs=34Hz and Qts=0.42, while the 18LW2400 driver has fs=35Hz and Qts=0.31. In a 160-litre vented-box enclosure, the 18LW2400 ends up having a much higher f3 cut-off frequency for any tuning that is relatively flat. This makes it less amenable to having its frequency response extended lower when the enclosure volume is fixed at 160-litres. The effects of the difference between a driver with Qts=0.42 and one with Qts=0.31 are very strong and cannot be overcome (at least I can't seem to).
@witwald I greatly appreciate the extensive sim and detailed post. Thats a serious driver. I agree with the higher Qts being beneficial and comparing smaller differences in dampening which can really affect F3 and F10. Running into excursion limits at a few hundred W isn't necessarily a problem but it can get away from you fast depending on the material you're playing.
There's also the magic Qts range which i usually favor for QB3 alignments. A Qts of .37 to .43 fits into this scheme and allows for better transient response. Group delay can be an issue but its generally not severe with carefully thought out QB3 alignments.
There's also the magic Qts range which i usually favor for QB3 alignments. A Qts of .37 to .43 fits into this scheme and allows for better transient response. Group delay can be an issue but its generally not severe with carefully thought out QB3 alignments.
If you go ported, your #1 issue will be port velocity at high power levels. Most peoples’ ports are too small.
As far as I investigated it's not the velocity itself but the air particle displacement to port radius ratio.
I will soon provide an excel calculation tool for optimising port dimensions.
Here are my latest investigation results for port geometry that is in accordance with ideal ports published in papers by roozen and salvatti/button/devantier.
@perrymarshall I agree that most published port recommendations tend to be on the small side. I'm a firm believer on running the largest port you can for a given tuning, but that also means larger enclosures to obtain less port length (if the driver allows it). QB3 alignments usually call for large enclosures close to actual driver Vas with average loss factored in. In these instances, you can use very short, large area ports, consequently almost eliminating port resonances. Sometimes that can be a port with the same length as enclosure wall thickness ie. a simple hole. I'm a big fan of short, large area slot ports, closer to rectangular shapes. These offer more efficiency, less compression and other non-linear behavior.
B&C always had stiffer, more progressing suspensions and in certain designs audible motor noises due to the cooling.
I do not have my 18NW100s for very long time now, moved into higher end beasts.
If you work em at very low frequencies or use them fully around its Xvar value, or use em with motor facing out, then the issue is obvious. I do not believe that the newer revisions are worse. B&C always was this way. I have issues with it too, but trust me, there is worse out there. Much worse.
In any case, if it doesn't work out, then I would contemplate on the TBW too. No idea about SB Audience, and I know price might be restrictive, but better motor behavior drivers are FaitalPro.
I do not own 18TBW100 either. Just used them couple of times. I like them, but the previous concerns apply here too.
18SW115 is fairly more quiet to my knowledge (owned it too). But it is much more expensive.
That pretty much verifies my concerns and findings. Alot of B&C drivers have noisy motors but I usually stick to the ones that don't have that issue or use them in a range that doesn't exhibit any issues. The 8NDL51 is one of those drivers, which is a phenomenal midbass but suffers from severe motor noise if not properly acoustically loaded.
In the case of the 18NW100s, they aren't that noisy, but definitely not suitable for open baffle use, etc. Ironically, it has actual measured TSPs making them theoritically suitable for such application, but the motor noise won't fly here. More importantly, many people dismiss drivers as having noisy motors, but when installed in proper enclosures, they quiet right down due to air load on the cone equalizing pressure across both sides of the VC gap. This consequently slows down air flow across the restrictive VC gap area.
My goal at this point is to opt for the 18TBW100s and cross my fingers they will be close to spec. The larger spider is promising. Just about any other small spider PA driver I've used has had issues with motor noise related to increased excursion, even under published xmax. This is a tradeoff area of design, as a larger driver can be prone to lower mid resonances due to spider design. More narrow spider designs usually avoid this issue, unless they're very compliant or have progressive waves. This breaks up resonances by spreading them out over a wider FR, sort of like a higher loss dampened cone does.
In the case of the 18NW100s, they aren't that noisy, but definitely not suitable for open baffle use, etc. Ironically, it has actual measured TSPs making them theoritically suitable for such application, but the motor noise won't fly here. More importantly, many people dismiss drivers as having noisy motors, but when installed in proper enclosures, they quiet right down due to air load on the cone equalizing pressure across both sides of the VC gap. This consequently slows down air flow across the restrictive VC gap area.
My goal at this point is to opt for the 18TBW100s and cross my fingers they will be close to spec. The larger spider is promising. Just about any other small spider PA driver I've used has had issues with motor noise related to increased excursion, even under published xmax. This is a tradeoff area of design, as a larger driver can be prone to lower mid resonances due to spider design. More narrow spider designs usually avoid this issue, unless they're very compliant or have progressive waves. This breaks up resonances by spreading them out over a wider FR, sort of like a higher loss dampened cone does.
I think we might touch that topic before? The single spider on these leaks as hell, doing terrible noises. I had 8NDL64, and it was most tragic case of motor noises I heard. They didn't make it into one week of my ownership. It leaked through the dustcap to the front side so much.
Many more B&C mid drivers are similar to that, but those bigger ones around 12" and more are also SO LOUD, that this noise becomes acceptable due to the masking effect. Before I hear my new 12FW76s do that in the amounts that would not be acceptable , my ears are already clipping.
RCF drivers with their hyperventing technology act similarly. Not good choice for hi-fi use while fully exploiting its excursion capabilities.
Indeed many times, the issue turns acceptable when put in the enclosures. Not always though. But this experience, or knowledge, or feel for it, comes right out of your wallet. Noone can tell how is it for you, depending on your ears sensitiity.
Now the TBW indeed has better chances, as it is said it is ferrite version of SW product line, and has wider spider, which indeed behaves much better amongst B&C drivers. It tips the scale of noise and fair use - if you use it well, SW driver will not be unacceptably noisy. But the venting structure still IS different compared to the SW I believe.
Many more B&C mid drivers are similar to that, but those bigger ones around 12" and more are also SO LOUD, that this noise becomes acceptable due to the masking effect. Before I hear my new 12FW76s do that in the amounts that would not be acceptable , my ears are already clipping.
RCF drivers with their hyperventing technology act similarly. Not good choice for hi-fi use while fully exploiting its excursion capabilities.
Indeed many times, the issue turns acceptable when put in the enclosures. Not always though. But this experience, or knowledge, or feel for it, comes right out of your wallet. Noone can tell how is it for you, depending on your ears sensitiity.
Now the TBW indeed has better chances, as it is said it is ferrite version of SW product line, and has wider spider, which indeed behaves much better amongst B&C drivers. It tips the scale of noise and fair use - if you use it well, SW driver will not be unacceptably noisy. But the venting structure still IS different compared to the SW I believe.
Thanks for all that!
I have a pair of NERO-18SW1900D arriving this week, to be hifi subs in a huge room. Your simulations are very timely. 😀👍
I was planning to use 20" or 24" diameter sonotube with heights 22~28" for 160~200 liters Vb and your simulation confirm my projections.
Sealed is preferable to me, and more suitable for the end user as a TT will be a frequent source. Even with steep digital filters, the subsonic grunge of warps etc always seems to cause more issues with ported speakers.
@mikessi Sealed boxes are definitely easier to design successfully. Ported is a matter of experience and taste, but once you've done a few and understand basic rules, it becomes much more predictable. The trick is using good drivers with linear suspensions, quiet motors and don't skimp on enclosure volume. Port noise is a trade off. Usually I never run into issues with this, being I prefer QB3 alignments (Vas is close to the actual required Vb, so low tunings don't need long and small ports). Also, its a misconception that HD is always higher with ported designs vs sealed. This is due to lower excursion requirements for given SPL way down low for most properly done ported systems.
Subsonic induced issues aren't a problem if you employ the proper HP and incorporate (account for) it in your enclosure rolloff. I play my records quite loud and have a fluid damper on my TT. In addition to that I built a passive line level tunable notch filter from 8 - 12 hz. I also have a selectable passive line level HP on my main speakers. I applied for a patent on this recently to build and license for ported and other acoustically assisted LF enclosure designs.
@Crashpc Yes, we've had this motor noise discussion before with 8NDL51s and 8NDL64s. Its sad they design drivers this way just because of dealing with cooling issues the easy way. B&C is certainly capable of doing better with their financial backing and others have built reliable high power drivers with quiet motors. Eminence always has surprised me here with their neo kappalite line (KL3012LF, HO, to name a few). The CannaBass line is also superb, as it has an excellent motor with a very linear pass band with low HD, especially in the midbass. Their specs are also dead on. Funny how they are now owned by B&C, yet have quite a few superior performing drivers compared to them. 12FW76s are good drivers. The BG series are also great as VLF drivers ie. 15BG100
Subsonic induced issues aren't a problem if you employ the proper HP and incorporate (account for) it in your enclosure rolloff. I play my records quite loud and have a fluid damper on my TT. In addition to that I built a passive line level tunable notch filter from 8 - 12 hz. I also have a selectable passive line level HP on my main speakers. I applied for a patent on this recently to build and license for ported and other acoustically assisted LF enclosure designs.
@Crashpc Yes, we've had this motor noise discussion before with 8NDL51s and 8NDL64s. Its sad they design drivers this way just because of dealing with cooling issues the easy way. B&C is certainly capable of doing better with their financial backing and others have built reliable high power drivers with quiet motors. Eminence always has surprised me here with their neo kappalite line (KL3012LF, HO, to name a few). The CannaBass line is also superb, as it has an excellent motor with a very linear pass band with low HD, especially in the midbass. Their specs are also dead on. Funny how they are now owned by B&C, yet have quite a few superior performing drivers compared to them. 12FW76s are good drivers. The BG series are also great as VLF drivers ie. 15BG100
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