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Bill Fitzmaurice

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Everything posted by Bill Fitzmaurice

  1. I should have been more specific. It was AM radio, with dash board mounted speakers. Gosh awful. Even basic car radios today are far better. I recall an early recording session I did, circa 1970, where the studio monitors were Altec A7s. We listened to the playback and it was quite good. Then the engineer said 'And here's what it's going to sound like in your car', and he switched the playback to a couple of 6x9 inch speakers, with the signal high passed at 100Hz, low passed at 5kHz. It was enough to make one cry.
  2. There is absolutely no data that's of any value in their ad copy. I'd no more take a chance on that than would I on a car that that lists horsepower as 'a lot', 0-100 KPH as 'really fast', and fuel economy as 'quite good'.
  3. Not from personal experience. The only cabs I use are the ones I built. But Barefaced does seem to use better quality drivers than most.
  4. The Basslites come with spades, as do most of the price point Eminence. The higher end in-line Eminence have push terminals, but I've seen OEM Deltalites with spades.
  5. Some was recorded direct, some was recorded through their home built mixing console. Either way there wasn't much there below 70Hz. It wasn't so much because they needed to prevent stylus jump, RIAA equalization took care of that. The main reason was that the primary playback system of the time was car radios, so the sound was mixed to give the best possible result when listened to in a car.
  6. OEMs usually use spades because they're cheaper. In-line drivers tend to use spring loaded binding posts because they're preferred by the DIY crowd. There's no particular advantage to one or the other.
  7. 'Divots' and cups to line them can be added. Penn-Elcom is the most likely source of cups.
  8. Business marketing 101, you don't sell the steak, you sell the sizzle. However, with some due diligence you can tell if the steak is a prime cut of filet or a cheap cut of chuck. The Trickfish ad copy says they use Eminence neo drivers. That narrows down the possibilities to Basslite, Deltalite II or Kappalite frames and motors. They claim 300 peak (which is in itself a red flag) power handling. That narrows it down to Basslites. They won't be off the shelf Basslite 2010, or 2012 , but with a given frame and motor you can only do so much. In many cases the only difference between an off the shelf Eminence and an OEM is that the OEM has spade connectors rather than spring loaded binding posts, and the reason for that is spade connectors are cheaper. All available evidence points to Barefaced twelve inch drivers having a Kappalite frame and motor. That's hugely different from the Basslite.
  9. With only 25 watts you should consider not trying to get deep lows. In another thread the 30w Ampeg B15 is mentioned, with respect to how one can drive a goodly sized room with it. The answer is that the speaker is high Q, which results in a strong peak in the 80-120Hz region, at the cost of deep lows. If you doubt that is low enough, listen to any Motown recording from the 60s and 70s. That's what you're hearing. The technical term is damping. There's no mystery about it at all, you can model what it does in WinISD and HornResp, and I suspect other programs as well. The parameter you model is Qa, absorption losses. WinISD defaults to a value of 100, which is a bare box. A value of 50 is a with the cabinet lined, 10 is filled, 5 is filled and compressed. The result is seen on the SPL chart, the reason for the result is seen on the impedance chart.
  10. The main difference between a bass and a PA driver is who it's marketed at. The 3012HO and 2515 in my bass cabs are marketed as PA drivers. I don't look at marketing blurb, I only look at the results.
  11. Maximum output isn't about watts, it's about sensitivity and cone displacement. If you have two tens sensitivity and cone displacement are the same, and so is maximum output, whether they're driven by one amp or two.
  12. A bigger box doesn't add to the power capacity. If anything it lowers it, as excursion is more in a larger box, not less. What a larger box does give is higher sensitivity and/or lower extension, which lessens the power required for a given output in the low end. It's the classic case of Hoffman's Iron Law at work. If you're a bass player and you don't know what that is, you should. You deal with it every time you plug in.
  13. Most of those who write the ad copy and so forth don't explain it because they don't know what it means themselves. The larger the company the more likely that is, as the engineering and marketing departments tend to not be in the same building, if even the same country. If you've read anything Alex posted here in years past it's obvious that what's in his literature he either wrote or approved, so with BF you're getting it from the horse's mouth, as opposed to the other end.
  14. BF defines things more accurately than other manufacturers. For instance, using a range of suitability with respect to amp power, as opposed to a finite figure, is neither new nor unique. The hi-fi speaker industry has been doing that for as long as I can remember, which is probably longer than the average player here has been alive. I don't see anything Alex saying as being out of line. The only problem is that for the most part he's the only one saying it. What people should asking isn't why BF offers the information that they do, but why the rest of the lot don't.
  15. The answer is that chances are you'll never run that 800w amp at more than -3dB from maximum, and that puts you at 400w. A more likely -10dB puts you at 80w. What engineers consider is voltage swing. Watts don't cause a voice coil and cone to vibrate, volts do. An amp's current limit determines how low an impedance load it can drive. That just proves that they're not experts. Eminence builds OEM drivers to spec with off the shelf parts. It's like a Chinese restaurant menu. Choose a frame and motor from column A, a voice coil from Column B, a cone from Column C, a dust cover from Column D, and so forth. With the number of parts at their disposal the number of possible permutations is almost endless. The minimum number of drivers you must order to get your own OEM is fifty.
  16. When there's a disagreement between the data and the real world result it's almost always because the data is incomplete, or just plain wrong. I know a B-15 can do what you say, because I used to have one. If all you look at is watts then a Vox AC30 shouldn't be able to take off heads at 30 meters, but I know from experience that it can. These are just two examples of why watts alone tell you next to nothing, while most of the data that does tell you what you need to know to make meaningful real world comparisons isn't available.
  17. The load on a woofer at 1600Hz is roughly 1/16th what it is at 100Hz, so dropping the crossover to 700Hz won't make an appreciable difference where that's concerned. The midrange dispersion angle of a twelve at 1600Hz is roughly half what it is at 700Hz, so from that standpoint the lower crossover is highly advantageous. They can only do that by using a compression driver capable of going to 700Hz.
  18. I don't use Eminence Designer. I use WinISD 0.7 freeware for sealed and ported cabs.
  19. Different drivers, different cabinets. different crossover frequency.
  20. That's because at least half the result is based on the enclosure. Eminence can't give hard and fast numbers on the driver data sheet because they don't know what enclosure you're going to put the driver into. But you can figure it out, as least where Eminence is concerned. The data sheet SPL shows what the driver will do above roughly 200Hz. Go to the Cabinet Design pdf link on the driver catalog page. There you'll see the result below 200Hz in various cabinets. Ignore the charts above 200Hz in the cabinet design pdf. The charts are generated with speaker modeling software that's only accurate to 200Hz. Splice the pdf chart below 200Hz to the data sheet chart about 200Hz to see the full range result. That's the kind of chart that all speakers should have in their catalogs. The Eminence pdf also shows Maximum Acoustical and Maximum Input Power, which take into account both the thermal and mechanical limits, and Cone Displacement at full thermal power. The cone displacement chart is a bit deceiving, as it shows in grey how far the cone would travel if it was able to. What the grey line really shows is how much distortion rises as the cone tries to do what it cannot.
  21. As long as you're getting educated: https://www.puremix.net/blog/musical-instruments.html
  22. It wasn't QSC, they didn't make speakers 20 years ago. Maybe one of those other three letter companies, like JBL or EAW.
  23. Since they're both from the same manufacturer and the twelve costs more than the ten it's a very safe bet than the drivers are similar save for size. The likelihood that the ten has as much or more displacement as the twelve is nil. If it did the ten inch driver would be a more expensive driver than the twelve, so the two cabs would be equally priced, and the ten would have a higher power rating as well. It doesn't. Like a ladies sewing circle there's lots of talk, but they don't actually say anything.
  24. Is that range quantified by a measured SPL chart? If not you have no idea what the tolerance is. +/-3dB is one thing, +/-10dB is something else entirely.
  25. While the LA12850 has an 800w thermal rating the 5mm xmax limits it to 300w through much of the critical midbass range. Watts alone don't tell you everything you need to know.
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