Ricci Posted November 7, 2017 Share Posted November 7, 2017 I went back and looked at the Tymphany STW-350F specs and they are totally different from the specs that ITR posted from a PB16 driver. Originally I thought that these drivers would be quite similar or were at least using a similar build platform. After looking again there is very little similar between them at all. The frames are different, the STW-350 is 15" OD but the SVS appears to be 16" OD. The STW-350 is using an overhung topology with a 7.4" diameter coil. SVS says they are using an underhung 8" nominal diameter. That being the case both the surrounds and spiders would be different. The overall motor / gap / coil geometry would be much different as well. In fact it seems like perhaps the only parts shared would maybe be the motor case and backplate. Although the motor outwardly makes the drivers seem like close brothers it appears that they are more like estranged 3rd cousins. Modeling the 2 drivers using the parameters provided shows that they behave as differently as you would expect. The SB16 driver should be a completely different 3rd driver design. I must say this has gotten me interested in testing the SVS 16's again. 1 Quote Link to comment Share on other sites More sharing options...
ITR Posted November 7, 2017 Share Posted November 7, 2017 5 hours ago, Ricci said: I must say this has gotten me interested in testing the SVS 16's again. Please do that. Quote Link to comment Share on other sites More sharing options...
Electrodynamic Posted November 8, 2017 Share Posted November 8, 2017 On 11/6/2017 at 3:51 AM, ITR said: Sorry, I am little late to the party. Could you please point me to the newer thread, I could not find it. I did not mean that high moving mass would always be an indicative of high inductance, I was just replying to his question. T/S parameters below. Electrical Parameters Re 4.65 Ohm electrical voice coil resistance at DC Le 3.143 mH frequency independent part of voice coil inductance L2 8.938 mH para-inductance of voice coil R2 16.81 Ohm electrical resistance due to eddy current losses Cmes 898.19 µF electrical capacitance representing moving mass Lces 21.56 mH electrical inductance representing driver compliance Res 51.10 Ohm resistance due to mechanical losses fs 36.2 Hz driver resonance frequency Mechanical Parameters (using laser) Mms 491.600 g mechanical mass of driver diaphragm assembly including air load and voice coil Mmd (Sd) 464.350 g mechanical mass of voice coil and diaphragm without air load Rms 10.711 kg/s mechanical resistance of total-driver losses Cms 0.039 mm/N mechanical compliance of driver suspension Kms 25.38 N/mm mechanical stiffness of driver suspension Bl 23.395 N/A force factor (Bl product) Lambda s 0.045 suspension creep factor Loss factors Qtp 0.911 total Q-factor considering all losses Qms 10.428 mechanical Q-factor of driver in free air considering Rms only Qes 0.949 electrical Q-factor of driver in free air considering Re only Qts 0.870 total Q-factor considering Re and Rms only Other Parameters Vas 38.8458 l equivalent air volume of suspension n0 0.186 % reference efficiency (2 pi-radiation using Re) Lm 84.90 dB characteristic sound pressure level (SPL at 1m for 1W @ Re) Lnom 86.00 dB nominal sensitivity (SPL at 1m for 1W @ Zn) Series resistor 0.00 Ohm resistance of series resistor Sd 834.69 cm² diaphragm area Thanks for posting the complete T/S's (unlike what was available a year ago when I posted and you quoted me). Super stiff driver. But since you mentioned using a lazer for measurements, what is the actual Xmax (70% BL, 82% BL, etc), Xmech, Xsus? One-way figures of course. It's good to see someone with Klippel openly publishing the information on this driver. Thanks again. Quote Link to comment Share on other sites More sharing options...
ITR Posted November 8, 2017 Share Posted November 8, 2017 10 hours ago, Electrodynamic said: Thanks for posting the complete T/S's (unlike what was available a year ago when I posted and you quoted me). Super stiff driver. But since you mentioned using a lazer for measurements, what is the actual Xmax (70% BL, 82% BL, etc), Xmech, Xsus? One-way figures of course. It's good to see someone with Klippel openly publishing the information on this driver. Thanks again. Here you go. My 3 kW amplifier could not push it further than +/- 15 mm (~210 V peaks) so you don't actually see where the 70% limits are, but one can have a pretty good estimate. Quote Link to comment Share on other sites More sharing options...
Ricci Posted November 8, 2017 Share Posted November 8, 2017 4 hours ago, ITR said: Here you go. My 3 kW amplifier could not push it further than +/- 15 mm (~210 V peaks) so you don't actually see where the 70% limits are, but one can have a pretty good estimate. Looks like it is time to try that K20 out on the next big woofer across the bench. Judging by the slope of those curves it looks like the 70% BL point is going to be around 20mm. Quote Link to comment Share on other sites More sharing options...
ITR Posted November 8, 2017 Share Posted November 8, 2017 Yes, I will second that. A single channel of K20 should be plenty. Quote Link to comment Share on other sites More sharing options...
SME Posted November 8, 2017 Share Posted November 8, 2017 I should amend my critique to add that keeping cost low is likely a factor that went into the optimization. We DIYers often take for granted that actual parts cost is typically a much smaller percentage of the finished product cost in a retail offering than a DIY build. 5 hours ago, ITR said: Here you go. My 3 kW amplifier could not push it further than +/- 15 mm (~210 V peaks) so you don't actually see where the 70% limits are, but one can have a pretty good estimate. I don't know a whole lot about how Klippel testing works, but the amp should be able to achieve more excursion at Fs than below because of Qtc > 0.707. This may actually suit the SVS design well if the amp is unable to achieve its "peak" power rating for any useful length of time at Fs, even despite the impedance peak. The high Qtc would provide an extra boost where the amp can't quite "get there", but the amp would be able to go full tilt into higher frequencies where the mass and inductance really hold it back. The Klippel's look real nice as far as allowing lots of excursion with low THD. It'll probably look great in a standard measurement suite including CEA. However, the inductance variance seems pretty high to me. Maybe it's fine for a budget consumer sub. Still, I'd bet that it sounds a lot better, the lower the crossover point is. 1 Quote Link to comment Share on other sites More sharing options...
Electrodynamic Posted November 9, 2017 Share Posted November 9, 2017 10 hours ago, ITR said: Here you go. My 3 kW amplifier could not push it further than +/- 15 mm (~210 V peaks) so you don't actually see where the 70% limits are, but one can have a pretty good estimate. I had a feeling the driver was more linear than the 10 mm spec that someone on another forum eluded to. IIRC SVS mentions 20 mm Xmax (one-way) but it's nice to see the graphs. Pretty linear BL on the driver too. Big pat on the back for the shape of the curve. Thanks for showing us the curves. All of them are nice and symmetrical (which is actually more important than shooting for a high number irregardless of the shape of the curve). Quote Link to comment Share on other sites More sharing options...
Steve81 Posted November 9, 2017 Share Posted November 9, 2017 14 hours ago, Electrodynamic said: I had a feeling the driver was more linear than the 10 mm spec that someone on another forum eluded to. IIRC SVS mentions 20 mm Xmax (one-way) but it's nice to see the graphs. Pretty linear BL on the driver too. Big pat on the back for the shape of the curve. Thanks for showing us the curves. All of them are nice and symmetrical (which is actually more important than shooting for a high number irregardless of the shape of the curve). The numbers currently on the PB16's page are 95mm peak to peak Xmech and 82mm Xmax: 1 Quote Link to comment Share on other sites More sharing options...
Electrodynamic Posted November 10, 2017 Share Posted November 10, 2017 11 hours ago, Steve81 said: The numbers currently on the PB16's page are 95mm peak to peak Xmech and 82mm Xmax: Hence my post over a year ago asking for real numbers. 1 Quote Link to comment Share on other sites More sharing options...
T-H-E-P-I-M-P Posted February 23, 2018 Share Posted February 23, 2018 PB 16 U is one of the shitest subs i've ever heard. Super stiff bass (driver) and under-ported. TS parameters are not surprising Cant understand anyone enjoying this one Quote Link to comment Share on other sites More sharing options...
Infrasonic Posted February 23, 2018 Share Posted February 23, 2018 People like all sorts of crap. That's not too surprising. Quote Link to comment Share on other sites More sharing options...
lukeamdman Posted February 24, 2018 Share Posted February 24, 2018 I remember audio snobs singing the praises of a REL sub and how "accurate" it was. When put on the bench it was basically a distortion output machine. Quote Link to comment Share on other sites More sharing options...
shadyJ Posted March 9, 2018 Share Posted March 9, 2018 On 2/23/2018 at 11:37 AM, T-H-E-P-I-M-P said: PB 16 U is one of the shitest subs i've ever heard. Super stiff bass (driver) and under-ported. TS parameters are not surprising Cant understand anyone enjoying this one If you think the PB16 Ultra sounds bad, you are very lucky never to have been exposed to a truly bad subwoofer. The fundamental performance of it is pretty good, and it's amazing how much clean deep bass they manage to get out of a 15" driver. In conclusion, you are out of your mind. Quote Link to comment Share on other sites More sharing options...
bgadmin Posted June 22, 2021 Share Posted June 22, 2021 I dont know if anyone noticed but the thiele small parameters for SVS 16 ultra drivers were not accurate. This page https://buy.guru/sb16-and-pb16-ultra-driver/ lists the thiele small parameters of both iterations. Quote Link to comment Share on other sites More sharing options...
Ricci Posted June 25, 2021 Share Posted June 25, 2021 On 6/22/2021 at 5:36 AM, bgadmin said: I dont know if anyone noticed but the thiele small parameters for SVS 16 ultra drivers were not accurate. This page https://buy.guru/sb16-and-pb16-ultra-driver/ lists the thiele small parameters of both iterations. Nice link back to your website...Exactly where did these parameters for the drivers come from? Just a repost of factory SVS specs? You should be aware that the specs and Klippel results posted earlier in this thread are from a guy who knows what he is doing and has access to some of the best testing equipment available. Also driver specs that vary by up to 30% or more are considered in spec in most cases. This is very common in the industry. No two units will ever test exactly the same. The specs posted by ITR earlier are not that far off from the specs listed for the PB16U driver. Well within industry tolerance for drivers. Quote Link to comment Share on other sites More sharing options...
bgadmin Posted June 25, 2021 Share Posted June 25, 2021 @Ricci Indeed... the specs given are for both iterations. Moreover SVS doesn't list them at all, so how can that be a repost of SVS? Anyways they come from OEM manufacturer documents not to be found anywhere else. But i will agree if you say his measurements are within industry tolerances... You are the true guru after all. Quote Link to comment Share on other sites More sharing options...
Ricci Posted June 28, 2021 Share Posted June 28, 2021 A LOT of variation is allowed even from the best manufacturer's. SVS undoubtedly has a ton of internal documentation on the drivers. They could've sent the data to a reviewer or someone else. Word gets around. Those are the specs from the OEM? Quote Link to comment Share on other sites More sharing options...
bgadmin Posted June 28, 2021 Share Posted June 28, 2021 Yes these are specs from OEM. Quote Link to comment Share on other sites More sharing options...
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