Bill Fitzmaurice

[quote name='warwickhunt' timestamp='1432375946' post='2780927'] Puzzled! I thought you (among many) always advocated the vertical stacking of drivers as the horizontal was an inferior/flawed design and that the 'science' behind the reason was pretty conclusive. So are you saying that horizontal is as good as vertical... so long as there is a well designed cross-over? [/quote]It's not a crossover in the usual sense between a woofer and tweeter. Only one of the tens runs in the upper frequencies, so there are no cancellation issues. The two drivers operate in tandem only in the lows, where the wavelengths are long enough that the two drivers will only compliment and never fight each other. Still, if using one you should have it vertical, with the full range driver on the top. When using two they'll work best vertical, mirror imaged, so that the two full range drivers are adjacent.

[quote name='chris_b' timestamp='1432315128' post='2780435'] ...you are constantly telling people that what they hear and like is wrong because the science says it isn't right. [/quote]Show me where I did so. Please. Just once I'd like to see proof of what I'm accused of. Or ignore me. But do me the courtesy of not putting words in my mouth.

[quote name='chris_b' timestamp='1432295127' post='2780104'] This is the usual tedious one-sided tug-of-war. One side thinks the text book is more important than your ears and shouts down anyone who disagrees or thinks that ears are more important. [/quote]Show us an example. The only 'shouting' I've seen is from those who say that what they hear, or what they think that they hear, is all important, and that the science behind it is irrelevent, if not flat out wrong. Innumerable scientists have had to suffer this same nonsense, no matter what their field of study, going all the way back to Aristotle, extending right through to Hawking. If you don't understand how gear works and have only your ears to rely on that's all well and good. You don't have to be Enzo Ferrari to know how to drive a Ferrari. You do have to be Enzo Ferrari to invent the Ferrari.

You probably would have to open it up to find identifying markings. It's probably not a Silvertone, unless there was a UK company that used that name. In the US Silvertone was a store brand sold by Sears-Roebuck, many rebadged Coral and Danelectro, but not in the 1950s.

The K140 will give best results in a 2 cu ft (net) box tuned to 30Hz. A single 3 inch ID tube 8 inches long will suffice, as with the 150w power handling it won't create sufficient port velocity to result in chuffing.

[quote name='Conan' timestamp='1431586953' post='2772752'] Surely this thread is now a perfect example of irresistible force meeting immovable object? The two "sides" are so intransigent and convinced of their "correctness" that they won't listen to the other. [/quote]The interpretation of what the two 'sides' stand for depends on which you're on. Those on the purely subjective side who deny the benefits of objectivity make the assumption that engineers wear white coats, work in laboratories, and wouldn't know an E string from a pickup. I don't own a white coat, and I don't have a laboratory. My work clothes are well imbedded with sawdust, as is my 'office'. I don't know how long Alex has been a bassplayer, but I have been since 1965, and not immodestly would put my chops and ears up against [i]anyone[/i] elses. Just because I know how gear works doesn't mean I don't know how to use it.

[quote name='Beer of the Bass' timestamp='1431462152' post='2771687'] If this isn't too much of a digression, it's notable that those specific EVM and JBL drivers are much appreciated by bassists who often claim to get something from them which they're not hearing from a lot of more modern drivers. Which specific properties from a technical perspective might be responsible for that? You've been quite clear that transient response isn't it, but what [i]is[/i] it? [/quote]The main difference between a vintage EMV or JBL and most modern drivers is the Qes, which is basically the effective magnet strength. The lower the value the higher the effectivemagnet strength. Anything below 0.35 is considered low by modern standards. The EVM 15L is 0.25, the JBL E140 is 0.19. Very low Qes results in high sensitivity in the mids, but it also chokes off the low end response. The EVM15B is better, at 0.3. Its main limitation is the result of the short 3.3mm xmax. Today drivers with twice that xmax are common, and that translates to needing two 15B to get the same output as one good modern fifteen, or you can get as much output from a modern twelve as a 15B. Note that what many might think is better transient response with these drivers is actually less low end content. What might be mistaken for poor transient response in modern electric bass drivers may actually be more low frequency capability. Another possibility is with very high Qes drivers, 0.5 and higher, which are common in cheap cabs. They tend to be boomy in the midbass, which can be mistaken for poor transient response. Poor transient response is a common trait of subwoofers, but you shouldn't be using subwoofers in the midrange where poor transient response would be evident anyway. If you know what you're looking for in the specs you can find modern drivers that sound like vintage EV and JBL. The Eminence EPS 15C, for instance, nearly duplicates the EVM15B. But having the same 3.3mm xmax it doesn't quite make it as an electric bass driver by todays standards. They market it for pedal steel guitar. The EPS 12C nearly duplicates the EVM 12L, it's also marketed for pedal steel.

[quote name='vailbass' timestamp='1431438328' post='2771337']Here's a great example of how choosing a speaker on specs alone would be a major mistake; the EVM 15" speakers that I love are rated for 100 watts! [/quote]No professional loudspeaker designer, nor talented amateur for that matter, gives much attention to watts. Of the dozen odd driver parameters that are pertinent watts are possibly the least significant. This is just another example of those arguing against the science not understanding the science. The difference between a player who doesn't bother to learn the science and one who does is that the former knows that the EVM sounds good, the latter knows why.

[quote]Both cabs will get 250w.[/quote]That's probably not the case. Power distribution is a far more complicated issue than simple division. For that matter power delivery into a single cab isn't a constant. It varies with impedance, and impedance isn't a set value, it's different at every frequency. A typical 8 ohm rated speaker will have an actual impedance that may range as low as 5 ohms and as high as 50 ohms.[quote]Even if you run the amp at full chat, neither of them will receive enough watts to cause any damage .[/quote]Also not the case. Most speakers cannot take anywhere near their thermal rating before mechanical damage is a possibility. Most amps can put out at least four times their rated power for short duration peaks, and most will put out twice their rated power long term with high THD, as their power ratings are measured at low THD. The key to preventing damage is simple enough,though. If the speakers distort, turn it down.

[quote name='RandomBass' timestamp='1431283150' post='2769610'] Do any manufacturers state those specifications? [/quote]Barefaced.

Which has the highest excursion/driver displacement? That's what limits low frequency output. It's a bit of a trick question, since none of the listed examples tell you what their driver excursion limit/displacement is.

[quote name='Dad3353' timestamp='1431117538' post='2768051'] This is not a universal truth. Valve amps with o/p transformers need a cab connected, but most, if not all, solid-state amps are OK without. There may be[b] some, rare, exceptions[/b] I'm unaware of, of course. [/quote]Those exceptions would be transformer coupled first generation SS amps from the 1960s. They, like tubes, always have current flowing into the transformer primary, so a speaker load or a short circuit of the transformer secondary is required. With direct coupled SS if there's no speaker no current flows through the output devices and there's no problem.

Cabs don't hiss. Amps do. That's where you should be considering a change.

[quote name='robocorpse' timestamp='1430997509' post='2766664'] Would there be any sense in upgrading to HLF, or will a pair of HE do the job? [/quote]No, as that would create a chain in which the HE is the weak link. That scenario is one of the myriad of reasons why you should not mix cabs.

Get a second identical 410. Mixing cabs is a crapshoot.

[quote name='Marvin' timestamp='1430918386' post='2765920'] So does high cone excursion result in poor transient response, as implied by the 'pro' and said not to be the case by Alex Claber and Bill Fitzmaurice. Which is correct? [/quote]Note that I said that transient response isn't affected by excursion but by voice coil inductance. Some high excursion drivers also have high inductance voice coils. One could use a high excursion driver, notice that transient response was affected, and therefore conclude that it was the excursion that caused the loss of transient response. With an adequate engineering knowledge base one would not make that error. Also note that I said that musical instrument drivers don't have high inductance. Many PA drivers do. That's not an issue if the crossover from the woofer to the midrange driver occurs at a frequency low enough where the high inductance of the woofer has no effect. Well designed PA cabs, or bass cabs that use high inductance PA woofers and midrange drivers, do just that. But not all PA cabs or bass cabs that employ PA woofers are well designed.

[quote name='Sibob' timestamp='1430498850' post='2762124'] Yep, surprised it got the go ahead actually. TC Group supplies chips and drivers to a number of MI companies. Will be interesting to see how it plays out. [/quote]Probably no better those companies that were acquired by Loud Technologies. Small engineering driven companies seldom fare well once their direction is dictated by bean counters.

[quote name='Conan' timestamp='1430913167' post='2765823'] some people don't like to have their preconceptions challenged... [/quote]+1. When it's pointed out that the emperor is stark naked there is a faction who will insist that those who believe that to be true simply have not properly trained their eyes. As for the admirable auditory skills of various musicians, producers and engineers, most do the best they can with the tools that are at their disposal. Some do very well operating within that constraint. OTOH others come to the realization that sometimes what's required is a better tool.

[quote] I'm a bass player, songwriter & lyricist and (bad) singer. [/quote]No one I know of who's a good bass cab designer isn't a bass player. For that matter many of the better PA speaker designers are also bass players, Tom Danley being one example. We didn't learn the science as pure exercise in academia, we learned it because we wanted to know all of the hows and whys of how our gear worked. We didn't have to delve too far into the subject to find out that by using science we could do much better than what was already out there. In that quest the three of us, among others, have been supremely successful.

[quote name='Marvin' timestamp='1430834096' post='2765002'] Science explains what your ears are trusting. Your 'ears' and science don't live in different worlds. [/quote]+1. The beautiful thing about science is that it always works, whether you understand it or not.

[quote name='Jazzneck' timestamp='1430547688' post='2762435'] I have found that it makes no difference to my shot ears (and punters who have commented) on whether the cab is set horizontally or vertically. [/quote]It will make a differnce in the mids, and it will do so only off-axis. If you don't move from side to side on stage you won't notice it. If you don't have the cab tilted back or elevated so that you can hear the mids you won't notice it. If you don't have much in the way of mids, for instance with a raggae tone, you won't notice it either.

[quote name='xgsjx' timestamp='1430472398' post='2761690'] It depends on the 2x10 in question & how good it is at moving air. [/quote]+1. All ten inch drivers are not created equally, so neither are all 2x10s.

[quote name='alexclaber' timestamp='1430229342' post='2759200'] There's no link between high cone excursion and poor transient response - in fact the reverse is likely to be true because a driver which is operating within its linear region will have far better cone control than a driver whose voice coil is moving out of the magnetic gap on louder notes. [/quote]+1. Using the term 'slow responding' is an example of thinking within the realm of the speed of sound. If drivers operated under the constraints of typical mechanical devices this would be true. But they don't. The electromotive forces responsible for cone movement operate within the realm of the speed of light. What does affect transient response is high voice coil inductance (Le), because that is an electrical parameter, not a mechanical parameter. Very high Le drivers will have poor transient response in the higher frequencies. But musical instrument drivers don't have high Le values, nor is there any direct correlation between Le and driver size.

[quote name='jimcroisdale' timestamp='1430142810' post='2758337'] It's been a couple of years since I used Win ISD, but I have been having a look in the last hour or so, yes. :-) [/quote]When you model you need to consider not just the sensitivity charts but also the Maximum SPL chart. That's actually more important than sensitivity, as it considers sensitivity, thermal and displacement limited power handling. In the vast majority of cases you'll find ported to be superior to sealed cabs.

[quote name='jimcroisdale' timestamp='1430131211' post='2758164'] Is it fair to say that even a small cab (16x16x12in) would be better with a port then, given the use of an Eminence neo such as the Kappa/Delta/Basslite? [/quote]Have you software modeled both options? That's the first step in the design process. To be blunt, if you don't know how to use modeling software you can't design a speaker with any better result than you can playing darts while blindfolded. Through sheer luck you may make the occasional bullseye, but more often than not you'll do well to even hit the board at all.