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Steve81 last won the day on September 26

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About Steve81

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  1. The Data-Bass Member Equipment List

    A new addition for my space, Nathan's new 21.0LX, based on the UH21 driver.
  2. TC Sounds 15" sub

    That's what's stated on the AVS article at least. Amp looks more or less like this also.
  3. TC Sounds 15" sub

    I dunno, I hear Thilo is pretty confident in his numbers. Either that, or Mark @ AVS is having fun jerking everyone's chain. I lean towards the latter.
  4. Xmax Investigation

    Hi Contrasseur, I've got a formula and some thoughts (already mentioned) that might help you square some things away... The formula I use is from Acoustics by Leo Beranek: P(rms) = Square Root Of 2 * Pi * Frequency Squared * Rho * Sd * Excursion / Distance P(rms) is recorded in Pascals Rho is the density of air, which varies by things like temperature, humidity, elevation, and so on. Sd is the radiating area of the driver in square meters Excursion is also noted in meters, as is distance Here are a couple examples of backdooring excursion through that via excel. With the LMS, that seems to track Nathan's comment re: 39mm of excursion, and Josh's <65mm comment for the T3S2-19. Rho is altered between the two to account for temperature differences on the day of measurement, and assumes a ~600' elevation, and 50% humidity (and yes, Pi goes to more than just 2 digits).
  5. (8) Sealed Incriminator Audio Judge 21" build

    Ask and ye shall receive. BMS 2.83V / HST 2V 25.269Hz: 85.709dB / 84.146dB 31.86Hz: 89.399dB / 88.206dB 40.283Hz: 92.886dB / 91.03dB 50.171Hz: 95.6dB / 91.115dB 63.354Hz: 97.047dB / 89.231dB Again, subtracting 3dB from the BMS figures, you're looking at a sensitivity difference between 1-2dB from 25Hz-40Hz; 50Hz on up is in favor of the BMS (significantly so by 63Hz). In terms of impedance, the BMS never sinks below 8 ohms in this range, while the HST drops to a hair under 6 ohms around 55Hz. Keep in mind, both drivers are being tested in the same 4.2 cu ft cabinet, vs handicapping the BMS with a 0.5 cu ft enclosure.
  6. (8) Sealed Incriminator Audio Judge 21" build

    I'm one of those people that doesn't really post here much, but if I can learn something by attempting to answer the question, so much the better, right? Let's do a quick comparison between two DIY systems that have been measured: http://www.data-bass.com/data?page=system&id=110 http://www.data-bass.com/data?page=system&id=112 Now looking at the sensitivities of both on the low end, you get: BMS / HST 20.142Hz: 82.244dB / 80.773dB 16.113Hz: 77.937dB / 77.073dB 12.451Hz: 73.66dB / 72.45dB 10.254Hz: 70.517dB / 68.948dB Obviously since the BMS driver was tested with 2.83V, you'll have to knock off 3dB from it's numbers to equal the 2V test of the HST driver. Impedance is close enough between the two at the frequencies involved that it's not all that important (the BMS is higher except at 20.142Hz in any case). However, what I see from this comparison is that the low end sensitivity is relatively close, not 6dB+ off. This is in spite of the fact that the BMS driver has higher BL, less moving mass, and an Fs of 29.1Hz vs 20.1Hz. What I also see is that the top end of the BMS driver appears to be much more sensitive. As such, while it appears that you need to boost the bottom end considerably to achieve a flat response, the other way of looking at it is that you're cutting back the overachieving top end.
  7. Which would you choose Funk or JTR?

    While I doubt either choice would be bad, I'd also lean towards the Funk given it's solid measured performance (vs no data for the JTR).
  8. HST18 / HS24

    FWIW, Josh did also do passive tests on the Funk 18.0 and 18.0C, along with tests using their standard 2.4kW and 0.8kW amps. Not quite the same gap as with the Chase unit, but an interesting comparison nonetheless. 18.0 18.0c
  9. SVS PB-13 Ultra - thoughts & opinions?

    I've owned one in the past, and it's definitely a solid sub (literally and figuratively). It's 16-31.5Hz output is still top tier among the commercial units that Josh has tested. That said, it's getting a bit long in the tooth, and a lot of competition has cropped up. Output on the top end (i.e. 50Hz on up) is nothing to write home about either.
  10. Hi Josh, Any thoughts on using this driver full bandwidth given the lack of a 10Hz passing response? I know that THD is a relatively minor concern at that point given that cabin gain will end up reducing effective distortion in room. At the same time, it doesn't inspire much confidence about how the driver will hold up an octave below that.
  11. Depends on the application I suppose. Obviously you can use EQ to tame the hump, and if you have enough amp the drop in top end sensitivity doesn't matter quite so much. OTOH, if you're crossing over at 120Hz and attaching it to one channel of an iNuke 3000, it might matter a little more.
  12. Can't say it'd be my cup of tea either... The burst numbers from 16-31.5Hz are impressive, but the inability to post a 10Hz passing score and the mediocre top end sensitivity stick out compared to high performers like the UXL.
  13. There are always variances in the results due to a number of factors (environmental, equipment, human error, etc.). Given that Josh's results were within a dB of Paul @ AH's with the same sub, it would seem to reduce the possibility of human error or serious equipment issues. Of course, there are more nefarious possibilities I suppose (i.e. the unit could have been a ringer).
  14. Ignore the burst numbers a minute and look at the 115dB compression sweeps. The MTX requires a 144V input, which equates to ~2.6kW, while we can guess this sweep requires everything the Rythmik's 600W amp has to give. Now looking at 80Hz, this means the MTX requires ~6dB more power to deliver ~0.5dB more output than the Rythmik. That's significant, but that apparent gap is reduced when you look at the actual compression at 80Hz: 3.6dB for the MTX, and practically zilch for the Rythmik.
  15. To be fair, the MTX was running with the big handicap of a 1.25 cu ft box. Measured sensitivity was 82dB with 2.83V at 1m at 40Hz, which is quite low.