Hi,
I am looking to build a FAST system with a Faital pro 3FE22 for 150-20KHz and the rest will be handled by probably a 6" midwoofer from SB acoustics in bass reflex. Since the midwoofer actually doesn't has to do any mid duty, We need not worry about midrange performance. I will be bi amping them with a Minidsp fro crossover.
Since there is a DSP involved, I will be tuning the box frequency lower than the usual flat alignment and giving it a 6db boost at the port tuning frequency. This will allow it to go lower than what it normally does. I will also be using the DSP to filter out any frequency below the port frequency to reduce the unnecessary cone excursion since it produces no sound anyway.
So here is the question for all SBacoustics fanboys and experienced users. Which cone should I use?
In the arsenal, there is now coated paper, PP, ceramic, aluminium and Carbon fibre (although this one is a bit expensive). Their parameters are all similar and so is their simulations. Which one do you think will be the best to deliver a tight punchy bass? It will be a 17 liter box tuned to 35Hz with a 6db boost with the minidsp .I will probably have the high pass at about 30Hz.
All opinions are welcomed especially from all those who have first hand experience with the drivers.
Thanking all in advance.
Oon
I am looking to build a FAST system with a Faital pro 3FE22 for 150-20KHz and the rest will be handled by probably a 6" midwoofer from SB acoustics in bass reflex. Since the midwoofer actually doesn't has to do any mid duty, We need not worry about midrange performance. I will be bi amping them with a Minidsp fro crossover.
Since there is a DSP involved, I will be tuning the box frequency lower than the usual flat alignment and giving it a 6db boost at the port tuning frequency. This will allow it to go lower than what it normally does. I will also be using the DSP to filter out any frequency below the port frequency to reduce the unnecessary cone excursion since it produces no sound anyway.
So here is the question for all SBacoustics fanboys and experienced users. Which cone should I use?
In the arsenal, there is now coated paper, PP, ceramic, aluminium and Carbon fibre (although this one is a bit expensive). Their parameters are all similar and so is their simulations. Which one do you think will be the best to deliver a tight punchy bass? It will be a 17 liter box tuned to 35Hz with a 6db boost with the minidsp .I will probably have the high pass at about 30Hz.
All opinions are welcomed especially from all those who have first hand experience with the drivers.
Thanking all in advance.
Oon
Looking through Zaph's data I would say none of them - the SB17 is not a particularly strong performer in the bass compared to other similarly priced woofers. Where it excels is in the midrange (200Hz-1K) Since you are planning to use the SB17 only at very low frequencies, the only difference you will find between the different cone versions are slight variation in resonant frequency/VAS and sensitivity due to the small changes in cone mass. The linearity of the bass will not change significantly between the different versions because the motor and suspension are the same for all of them.
The Peerless 830883, Dayton RS180 and even the Dayton DA175-8 are a lot cleaner in the bass according to Zaph's data. The DA175 wants a bigger box (~25L) and it also needs to be tuned lower (30Hz), while the Peerless and RS180 are similar to the SB17 in box requirements. Group delay is virtually identical between all of them for >30Hz, so the only perceivable difference in 'punch', 'tightness' or 'speed' will come down to frequency response. The ones that are leaner in the frequency response down low (rolling off earlier) will probably sound faster/punchier/tighter. You can also achieve this simply by lowering the box tuning frequency.
The Peerless 830883, Dayton RS180 and even the Dayton DA175-8 are a lot cleaner in the bass according to Zaph's data. The DA175 wants a bigger box (~25L) and it also needs to be tuned lower (30Hz), while the Peerless and RS180 are similar to the SB17 in box requirements. Group delay is virtually identical between all of them for >30Hz, so the only perceivable difference in 'punch', 'tightness' or 'speed' will come down to frequency response. The ones that are leaner in the frequency response down low (rolling off earlier) will probably sound faster/punchier/tighter. You can also achieve this simply by lowering the box tuning frequency.
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audioexcite has measurements for the SB17 carbon fibre (CRC), aluminium (NAC) and paper (NRXC) versions. The carbon and aluminium ones look more or less the same, paper LOOKS much worse at initial glance until you realise that the distortion plot starts at 100Hz instead of 200Hz! It is however a tiny bit worse than the others. Could be down to manufacturing variation, or maybe SB have refined the design a little over time (the NRXC was introduced way before the other cone types)
Zaphs measurements are done at 92dB/0.5meter which corresponds to 86dB/1meter. On his graph the fundamental is at -10dB which makes 1% about -50dB, 0.1% about -70dB and 0.01% about -90dB. The audioexcite measurement of the NRXC shows ever slightly higher distortion than Zaphs, though it is done at ~4dB higher level.
The CRC and NAC versions look nice over the range that audioexcite tested them - at 200Hz they are about the same as all the others mentioned above. Unfortunately we don't see <200Hz in audioexcites measurements of the CRC and NAC versions so it's impossible to draw a conclusion about how good they are over the 30-150Hz range that the OP wants to use them.
Zaphs measurements are done at 92dB/0.5meter which corresponds to 86dB/1meter. On his graph the fundamental is at -10dB which makes 1% about -50dB, 0.1% about -70dB and 0.01% about -90dB. The audioexcite measurement of the NRXC shows ever slightly higher distortion than Zaphs, though it is done at ~4dB higher level.
The CRC and NAC versions look nice over the range that audioexcite tested them - at 200Hz they are about the same as all the others mentioned above. Unfortunately we don't see <200Hz in audioexcites measurements of the CRC and NAC versions so it's impossible to draw a conclusion about how good they are over the 30-150Hz range that the OP wants to use them.
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IMO you could consider a larger driver , 7"-8". RS225 and RS180 have good XMAX which may be useful for DSP improved bass.
It means less with DSP levelling but 3FE22 is very sensitive. Traditionally, you'd employ at least a pro 8" or a pair of them to match sensitivity. Unless you LPAD the 3FE22, arguably you are reducing resolution of the majority of the sound spectrum if levelling is done in the digital domain in DSP.
J.
It means less with DSP levelling but 3FE22 is very sensitive. Traditionally, you'd employ at least a pro 8" or a pair of them to match sensitivity. Unless you LPAD the 3FE22, arguably you are reducing resolution of the majority of the sound spectrum if levelling is done in the digital domain in DSP.
J.
Thanks for the tip. They will be fed to two different amps with different gains. A class D for the woofers and a low powered low gain class A for the Faitalpro. In the end they should about level up. As for the 8". I am trying to keep the sub small, 8" would blow it up significantly...
Oon
I agree that Goran's measurements aren't complete but I was looking at the general shape of the 2nd order plot. Even though it's only down to 200Hz the NAC version has a completely flat 2nd harmonic. The paper version has been rising for quite a while already by 200Hz and it's almost an order of magnitude worse than the aluminium version in the 95dB test at 200Hz.
We do not see when the aluminium version starts to rise, as the test cuts off, but I'd expect it to be pretty decent, at least far better than the paper version.
I agree with the recommendation for the RS225 though. Can't go wrong with that driver.
I have actually heard some of the SBacoustics in action and I am quite impressed by them for bass. I have heard the Uluwatu and the Ara Kit. Although the T-s parameters looks similar as any of its Scandinavian half brothers (they have the same daddy), they are actually quite different. Many of the midwoofers have freq response to 15-20KHz. Some of their drivers particularly the 4ohms (For example the SB16PFC25-4) has a huge peak at 40Hz. Quite unusual but will help with the bass response. This cannot be explained purely by the TS parameters.
I also belong to the camp that believes every speaker cone material has its own acoustic signature. I am more inclined to the either the aluminium at the moment (you try telling someone your subwoofer has a frequency response to 20KHz) for cone stiffness, or possibly the ceramics. Actually my first choice is the carbon fibre, but they are quite a bit more expensive than the rest.
Thanks.
Oon
Thanks Scott, very interesting speaker. I actually own a pair of fairly similar speaker which is a 6.5" tangband W6 1139 and constructed a subwoofer in a sealed. I coupled them so they face opposite direction and cancel each other's cabinet vibration. They work very well. They don't work so well in BR for a very simple reason, which will happen to any high xmax speaker. The airflow is so high that you will need a really large port. I would think that the exodus would need a port of at least 3" to keep port velocity at reasonable level. That would balloon the size of the box tremendously to get a 35Hz tuning, not to mention some crazy port length. In the end you would figure, you can get the similar effect with a 8" midbass...
I have tried some simulation on the SB acoustics. At port tuning frequency. The excursion is pretty minimal, only a few mm even at 40 watts. The real excursion is at 50-60 Hz. The part where the excursion goes nuts is when it goes below port tuning frequency. Since I am limiting that anyway. Should not be an issue.
The other factor that troubles me is the weight of the cone. Which is really heavy for its size. Similar issue with the tangband. At 30g, it's going into a 10" midbass territory. My tangband SB acoustics for example is only about 13 grams. I am a bit concerned on the transient response.
My own personal experience, is you can't get a subwoofer to do midbass work well. It will sound a bit slow..
Anyway I plan, to compare the performance of my sealed tangband vs the midbass in BR to compare the difference especially in the region of upper bass.
Thanks for the suggestion. Learnt something new.
Oon
I have tried some simulation on the SB acoustics. At port tuning frequency. The excursion is pretty minimal, only a few mm even at 40 watts. The real excursion is at 50-60 Hz. The part where the excursion goes nuts is when it goes below port tuning frequency. Since I am limiting that anyway. Should not be an issue.
The other factor that troubles me is the weight of the cone. Which is really heavy for its size. Similar issue with the tangband. At 30g, it's going into a 10" midbass territory. My tangband SB acoustics for example is only about 13 grams. I am a bit concerned on the transient response.
My own personal experience, is you can't get a subwoofer to do midbass work well. It will sound a bit slow..
Anyway I plan, to compare the performance of my sealed tangband vs the midbass in BR to compare the difference especially in the region of upper bass.
Thanks for the suggestion. Learnt something new.
Oon
Just a note to nomenclature as i still haven’t played with any available 6-8” drivers yet, except the Mark Audio Alpair 12pw, it wants a bigger box than it seems you can give it.
We are trying to deep six the FAST term, it seems to be universilly despised.
The new term is WAW (Woofer Assisted Widerange) — much more description and accurate.
dave
We are trying to deep six the FAST term, it seems to be universilly despised.
The new term is WAW (Woofer Assisted Widerange) — much more description and accurate.
dave
You aren't wrong, but I would be weary that it might not be a fair comparison because the measurements were not done under the same conditions. Sweep speed, driver decay, and windowing come in to play because the driver momentarily experienced unfavourable operating conditions at 100Hz a split second before the 200Hz measurement occurred.
No doubt, different cone materials can have significantly different behaviour at higher frequencies and that 'colours' the sound. The breakup on the SB17 occurs at more than 10 times the highest frequency that the OP wants to use it, so every type of cone will be perfectly pistonic and add no colouration to the sound. The only colouration will come from the motor and suspension (surround, spider) which I suspect are exactly the same between all versions.
Since the woofer is only being used for bass (30-150Hz) the key influence to the bass quality will be group delay, frequency response and non-linear/harmonic distortion. If a woofer is 3dB down at 40Hz compared to 80Hz, that is going to produce a difference bass sound when an instrument plays at a 40Hz fundamental, compared to a woofer which is flat from 40Hz to 80Hz, because the ratio between the instruments fundamental tone and 2nd harmonic have been altered. The effect of group delay also affects the bass. Bad group delay results in a woofer which does not respond well to quick bass notes but plays loudly when there is a long droning passage. A lower tuning/resonant frequency or sealed box gives lower group delay at a given frequency.
The influence of a 6" woofers cone breakup nodes does not even come in to play if it is crossed at 150Hz because the woofer is not playing any content up at those frequencies (several kHz). The focus in picking a woofer which produces the least amount of colouration/distortion should be in finding one that is a good compromise of low non-linear distortion and producing a flat frequency response over the frequency range that the OP wants in a reasonable sized box without resorting to higher tuning (which would cause bad group delay).
The 'sound' of bass also has lot to do with what is happening higher up. When an instrument makes a crisp snappy bass sound there are not just bass frequencies produced but also mids and treble because there are a lot of harmonic tones to go a long with the bass fundamental tone. Without the mids and highs all bass instruments just sound like a sloppy wet farts.
Since the OP plans to use another driver to handle the mid and treble, the perceived quality of the bass in the finished speaker will not only depend on how the woofer behaves but also how the mids/tweeter handle the high order harmonic content of the bass instruments.
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We have had really good luck with the Silver FLute W14 (5 ¼”). We get 35Hz anechoic F10 in the Woden ML-TL we use and have fit it into as small as a 5 litre miniOnken (actually 2 in 10 litre — it doesn’t go near as low, but sounds good). Both WAW.
dave
Thanks TMM for the long clarification. I actually have another thread of understanding bass reflex simulation. You managed to explain to me what to look out for when simulating.
I think generally the sound should be similar it is a matter if the cone is stiff enough to handle the back pressure of the box. I which case, probably the ceramic or aluminum should be the choice I guess in terms of cone stiffness without having to pay for carbon fibre..
Oon
I would consider this SB driver:
SB Acoustics :: 6" SB17NBAC35-4
Heard it a week ago, and it plays VERY smooth, open and no problem going down to 30-35 Hz - It was crossed around 2K Hz.
I currently own a pair of SB17MFC35-4 and these have also no issues going to 35 Hz in a 16 Liter cabinet (basreflex)
SB Acoustics :: 6" SB17NBAC35-4
Heard it a week ago, and it plays VERY smooth, open and no problem going down to 30-35 Hz - It was crossed around 2K Hz.
I currently own a pair of SB17MFC35-4 and these have also no issues going to 35 Hz in a 16 Liter cabinet (basreflex)
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