stevie

[quote name='civilian_project' post='429400' date='Mar 9 2009, 02:25 PM']okay so say i cant find an original pbass pickup. What'd be your best suggestions for that lovely motown vibe? Jamersonesque. [/quote] I can recommend the Duncan SPB-1 for that, although flatwound strings will probably get you closer than anything else you can do.

[quote name='alexclaber' post='425679' date='Mar 5 2009, 12:52 AM']Resonant frequency is a function of moving mass and suspension compliance: Fs = 1/(2*pi*sqrt(Cms*Mms))[/quote] Exactly. This shows that there is a relationship between a speaker’s resonant frequency and its moving mass. And because there is a direct relationship between moving mass and cone size (double a cone’s area and you double its mass), there is also a relationship between driver size and Fs. Blindingly obvious really. Thanks for that. [quote name='alexclaber' post='425679' date='Mar 5 2009, 12:52 AM']So your answer is to use a thick heavy cone and loose suspension.[/quote] In theory, yes, but there are physical limits to what is possible. Still, if fs and driver size were truly independent, you would be able to produce such a driver. The fact that you can’t shows they are not independent. [quote name='alexclaber' post='425679' date='Mar 5 2009, 12:52 AM']The problem with a 1" woofer with an 18Hz Fs (assuming huge Xmax to get sufficient Vd) would indeed be related to radiation impedance but that is an extreme example.[/quote] Indeed, but in simple terms, the driver would have to have a cone made out of lead and a suspension made out of Durex. It would in fact cease to be a loudspeaker at all.

[quote name='escholl' post='427612' date='Mar 6 2009, 09:51 PM']i'm sad, i know. [/quote] There's nothing sad about being interested in how things work and are made. Watching Coronation Street - that's sad.

[quote name='liamcapleton' post='426416' date='Mar 5 2009, 04:44 PM']Copeland's great... but hard to hold a flame to Vinnie Colaiuta playing on Sting's solo stuff... check it out: [url="http://www.youtube.com/watch?v=9RbOFm8W5Wk"]http://www.youtube.com/watch?v=9RbOFm8W5Wk[/url][/quote] Wow! That is just stunning. Never heard it before. Thanks for that.

[quote name='Sharkfinger' post='426154' date='Mar 5 2009, 01:51 PM']So what I'm getting from this, right or wrong, is that by a rule of thumb the more cone surface area the more LF is produced, whether that be a single large driver (bass bin) or multiple smaller ones (8x10" 'fridge'). Or is my horribly over-simplifying matters making you speaker aficionados tut and shake your heads in exhasperation? [/quote] There are other factors involved, but yes, it's a reasonable way of looking at it.

[quote name='josh3184' post='425683' date='Mar 5 2009, 12:58 AM']I shouldn't have wandered into this thread again, I feel completely stupid now after reading that post![/quote] I thought it was a most welcome diversion, although not quite as hilarious as some of the other posts in this thread.

[quote name='Clockworkwar' post='426089' date='Mar 5 2009, 12:53 PM']What is the minimum airflow for a solid state amp mean't to be?[/quote] The airflow is related to the speed of the fan, which is related to the consumption of the motor. The latter should be printed on a label in the centre of the fan. Papst and Panasonic have a reputation for low noise and good build quality, although you are unlikely to find them in your local computer shop.

[quote name='wotnwhy' post='425404' date='Mar 4 2009, 06:32 PM']not a penny! though i did have a bit of a 'mare getting the old speaker out as the screws holding it in had spanner heads as opposed to screwdriver. and i didn't have any spanners...[/quote] So, all's well that ends well. And you have a spare speaker. Not bad!

[quote name='Bill Fitzmaurice' post='425388' date='Mar 4 2009, 06:14 PM']No, I just ignored it.[/quote] I know that. I was just being polite. [quote name='Bill Fitzmaurice' post='425388' date='Mar 4 2009, 06:14 PM']Driver size and Fs are independent of each other.[/quote] You keep coming up with these ridiculous statements, Bill. Everyone knows that there is a relationship between driver size and Fs. Or perhaps you could tell us how you would build a 1" woofer with a resonant freqency of 18 Hz.

[quote name='escholl' post='397248' date='Feb 1 2009, 09:01 PM']A driver with a defect may well have worked fine for a bit, only to fail rather quickly in it's lifespan.[/quote] I agree - and that's definitely a defective driver. I've come across the problem before. It's caused by one of two things: inadequate venting of the volume behind the dome, or inadequate gluing of the dome. Manufacturers like ATC use Araldite to glue their domes because they had the same problem in the early days. Fane had the problem at one time when they put a foam bung in the rear vent, which restricted venting and put pressure on the domes. It looks like the driver manufacturer has now found out about the problem and has strengthened the glue joint. I hope you didn't have to pay for the replacement.

[quote name='bass_ferret' post='425345' date='Mar 4 2009, 05:40 PM'] [/quote] Hey, what’s with all the sexual innuendos? Can't you see there is some seriously nerdy nitpicking going on here? Anyway, it’s not the size of your bass driver that counts – it’s what you do with it!!

[quote name='Bill Fitzmaurice' post='423271' date='Mar 2 2009, 02:43 PM']Tens and twelves capable of the same response do exist, and with equal total Vd will give equal output.[/quote] Bill, you must have missed my earlier post when I explained that this statement was misleading. Otherwise, I’m sure you would not have repeated it here. To clarify, Vd is no more than an expression of how much air a speaker can shift. You cannot predict output based on Vd alone. System efficiency, or how air movement is converted into sound, matters. For example, we are all familiar with how a speaker can shift lots of air outside a cabinet without producing any audible low frequencies at all. Bigger drivers, with their lower resonant frequency and superior radiation impedance, are by nature more efficient reproducers of low frequencies. The higher resonant frequency of a smaller driver means a higher rollof in a reflex system, which reduces their efficiency at low frequencies. Big drivers are designed to produce bass - that’s what they do. You don’t build a motorway with shovels, no matter how many you’ve got. You get the bulldozers in.

The Neutrik ones are great and will last a lifetime. Just make sure you don't get the ones with the black plastic tops on them. They are a poor design, because you need at least a 60W iron to solder the wires.

[quote name='cheddatom' post='420966' date='Feb 27 2009, 02:53 PM']So do the same experiment with a the 15" on top and report back.[/quote] Or better still, just compare them side by side.

[quote name='Sharkfinger' post='423161' date='Mar 2 2009, 01:19 PM']Also have a relevant (probably stupid) question: if driver diameter has minimal effect on frequency generated and it's all down to cabinet tuning, why are PA subs traditionally loaded with 15" or 18" drivers, especially in higher power applications?[/quote] It's a perfectly valid observation. The reason is that sound reinforcement professionals know that, given a level playing field, a larger driver is capable of producing more bass than a smaller one. Twenty-one inch drivers are quite popular now. Also, 'real' bass drivers don't need to reproduce the midrange.

[quote name='far0n' post='421024' date='Feb 27 2009, 03:41 PM']I think the best I've had was my Eden D410XLT at 106db. Haven't come across any louder than that from the main manufacturers.[/quote] What do you think makes them so loud?

[quote name='fusionbassist1' post='420251' date='Feb 26 2009, 05:48 PM']I've been using a set of Wizard 84s in my pride-and-joy-spec'd-everything-that's-in-it Jazz bass but am not quite feeling the love from these pups right now ...[/quote] If you do talk to Wizard, I think you'll need to be a bit more specific about what the problem is.

[quote name='Bill Fitzmaurice' post='420174' date='Feb 26 2009, 04:04 PM']+100. The assumption is made that the larger driver size will result in a lot more low end. It won't.[/quote] It usually will. It is, of course, always possible to describe an exception that proves the rule but, by and large, the bigger the driver, the more low end. [quote name='Bill Fitzmaurice' post='420174' date='Feb 26 2009, 04:04 PM']The low end output capability of a cab is mainly determined by the total volume displacement of the drivers, Vd.[/quote] The key factor here is not Vd but the efficiency of the system at low frequencies. For the same overall efficiency, a large driver in an appropriate box is always going to extend lower than a smaller one. I might add that this is obvious to anybody with half a brain. Vd is a factor in determining maximum output but is has no relevance to low frequency extension. [quote name='Bill Fitzmaurice' post='420174' date='Feb 26 2009, 04:04 PM']The Vd of the average 4x10 is about 400 cc, that of the average 1x15 300 cc. If one is going to get more LF output by adding 1x15 to a 4x10 the 1x15 should have considerably more Vd than the 4x10, not less.[/quote] Not necessarily. Much depends on the efficiency of the systems at low frequencies. The "average 4 x 10" containing drivers with an Fs of around 60Hz will be quite inefficient at 40Hz compared with a well designed 15" cab. [quote name='Bill Fitzmaurice' post='420174' date='Feb 26 2009, 04:04 PM']Where portability is desired for small gigs I'd add a 2x10, not a 1x15. Preferably the same brand, using the same drivers, at twice the impedance of the 4x10.[/quote] That won't help in the slightest. It will sound the same, only louder. By the way, the reason Bassman's 15" system didn't add any extra bottom end is probably because it didn't have any extra bottom end to add. That would be par for the course with that cab and the more popular Eminence 15" drivers.

[quote name='alexclaber' post='419163' date='Feb 25 2009, 12:10 PM']Exactly - there are no 12" cabs currently available with enough volume displacement (cone area x cone excursion) to handle high SPL 5-string action unless you are willing to give up a lot of bottom. There is a new Eminence 12" on the way that will be able to do this but the downside is the price of a completed cab because it has to be used with a midrange driver unless you're solely playing reggae.[/quote] What exactly is this new Eminence driver that will outperform all currently available models?

[quote name='OldGit' post='419133' date='Feb 25 2009, 11:35 AM']So (numpty here) the midi files convert into dots of Sibelius? Is that how it works?[/quote] Yes, Sibelius and similar programs provide you with a complete arrangement in standard notation. PM replied to.

Or go here and follow the links: [url="http://www.midisite.co.uk/"]http://www.midisite.co.uk/[/url]

I've got a large collection. PM me some titles and I'll see what I can do.

[quote name='Merton' date='Feb 24 2009, 12:50 PM' post='418315'] ............ it's a very compromised and badly designed cab (hence Stevie's comments) I didn't mean to suggest that your cab was badly designed - far from it. It looks good to me. It's just that the Eminence Beta will sound boomy in virtually any box you put it in. But you've modelled it - you know that.

[quote name='Merton' post='417814' date='Feb 23 2009, 08:28 PM']The LH500 makes it sing...[/quote] With the Eminence Beta in there it will doubtless be singing the One Note Samba.