Bill Fitzmaurice

[quote name='Fraktal' post='252047' date='Jul 31 2008, 09:06 AM']Thanks a lot for your insight, Alex, always good to learn new things. Unfortunately I think Im having a hard time to understand your response, do you have any graphics? Maybe it would be easier with a picture or 2...[/quote] Graphics in this case is a culprit. The 'underpowering' nuts show a picture of a square wave as it appears on an oscilloscope to bolster their case. Musical waveforms of that sort do not exist. A clipped musical waveform consists of a normal sine wave at the fundamental to which has been added an abnormally high level of harmonics. Those harmonics can result in overpowering of tweeters, and in extreme cases midranges. They have absolutely no effect upon woofers.

[quote name='Mr. Foxen' post='251309' date='Jul 30 2008, 08:28 AM']run your amp into clipping and put a square wave dc current into your speakers[/quote]Said 'square wave DC current' falls into the same category as Medusa, Chimera, Unicorns, Hercules and Fiscal Responsibility in Government.

[quote name='waynepunkdude' post='248875' date='Jul 27 2008, 07:50 AM']I played with a band a few weeks back, the bass player had the same cab as me (Ashdown 4x10) so we decided instead of stacking them we set one up on each side of the stage and it sounded amazing, not much help but I'm never much help.[/quote] There probably were some places where it sounded amazing, but they would have been exceeded by those where it sounded worse than if stacked. A visual representation of why using spread low frequency sources is a bad idea found here: [url="http://www.falstad.com/wavebox/"]http://www.falstad.com/wavebox/[/url] BTW, the same destructive interference that occurs at low frequencies with cabs placed more than a few feet apart occurs in the mids and highs when drivers within a cab are horizontally mounted.

[quote name='bass_ferret' post='248504' date='Jul 26 2008, 12:03 PM']But is wide dispersion always desirable?[/quote]Dispersion is not a constant, it varies with frequency. No matter how a cab is oriented low frequency dispersion (roughly 400 Hz and below) is 360 degrees. Going higher in frequency the dispersion angle narrows as frequency goes up, so the cab sounds different depending where you're standing. The wider the dispersion angle is maintained with increasing frequency the more uniform it sounds within the listening area.

[quote name='bass_ferret' post='248346' date='Jul 26 2008, 06:55 AM'] Your'e a glutton for punishment The fallacy that the "bass" cab goes on the bottom and the "treble" cab goes on the top when they are both reproducing the same signal (unless they are actually being bi-amped) is an extension of the fallacy that a stack has to have 15's and 10's.[/quote] It's not a matter of both reproducing the same signal, it's a matter of dispersion. Even if the 15s and 10s have exactly the same frequency response chances are the tens will have wider dispersion in the midrange, so better to have them on top where that dispersion can be put to good use. [quote]The cabs on their side bit arranges the drivers vertically. This is because of another bit of science that may or not affect the sound (in your opinion) etc etc. Horizontal arrangement of drivers causes something called comb filtering or lobe filtering, where phase cancellation causes peaks and troughs in SPL depending on your position relative to the cabs.[/quote]The existence of comb-filtering isn't a matter for debate, it's a phenomena well known for at least 75 years. Those who deny its effect should also consider memberships in the Flat Earth Society. OTOH elimination of combing is not the overriding reason for vertically aligning drivers. Expanding the width of the horizontal plane of dispersion, as Alex explains above, is. Second to that is the narrowing of the vertical dispersion pattern, placing more sound in the audience, unless you're playing to dust mites on the floor and bats in the belfry. As a benefit of vertical alignment the elimination of combing comes in third.

[quote name='labougie' post='247261' date='Jul 24 2008, 03:47 PM']I'm coming back to bass-playing after many years away from it. I've got a pair of 1225e Celestions (300w, fs 61Hz, Xmax 3.3mm, XMech 12mm). Would I be banging my head against a brick wall trying to build two 1x12 cabs with these, driving them with maybe 250 watts of Peavey and expecting to get enough bottom end to do small pub gigs with?[/quote]You won't knock walls down but they'll do for a small club. 3.3mm xmax is about average for OEM drivers. Do the cabs right and you'll likely be better of than with commercial 1x12s.

[quote name='stevie' post='245674' date='Jul 22 2008, 03:52 PM']The SRX series is shown using the 2226H on the current JBL Pro website. [url="http://www.jblpro.com/pages/mi/srx/srx.htm"]http://www.jblpro.com/pages/mi/srx/srx.htm[/url][/quote] Check the publication date on that obsolete link. As opposed to this one: [url="http://www2.jblpro.com/catalog/general/ProductFamily.aspx?FId=10&MID=3"]http://www2.jblpro.com/catalog/general/Pro...Id=10&MID=3[/url] Also consider getting a life.

[quote name='alexclaber' post='245200' date='Jul 22 2008, 06:09 AM']curved sided cone, and concentric ribbing around the cone, all of which allow the cone to flex Alex[/quote]Those refinements are intended to make the cone stiffer, to reduce flex and along with it break-up. So doing allows a lighter cone material, and the benefits of same, which includes a higher response. The ribbing is similar in look, but not function, to Altec bi-flex drivers, which incorporated a surround in the cone that allowed more independance between a stiffer/lighter inner cone and softer/heavier outer cone.

[quote name='redstriper' post='244949' date='Jul 21 2008, 06:44 PM']would like to hear from people who have actually heard all 3 in the flesh[/quote] I've heard those and perhaps 100 more fifteens over a 40 year span. IMO for a single driver cab the 3015 is unexcelled. The 3015LF is even better in extension and power handling but should be used along with a midrange driver, although for raggae and dub one might get along without it.

[quote name='stevie' post='244815' date='Jul 21 2008, 04:12 PM']The off-axis performance of a 2226H is a function of its diameter. It is no better or worse (and its response doesn’t drop off any faster) than any other 15 inch driver.[/quote]Off-axis response as a function of cone diameter assumes that the cone operates as a single pistonic radiator. In the case of extended range musical instrument and pro-sound drivers the dome acts as an independant midrange radiator, and the response both on and off-axis is not a function of cone diameter alone. [quote]JBL uses the 2226 in its current SR-X series[/quote]The SRX715 and SRX725 have used the 2256 neo magnet woofer since 2004.

[quote name='stevie' post='244655' date='Jul 21 2008, 01:19 PM']The JBL 2226H... good quality extended midrange.[/quote] On-axis plots may give that indication, but off-axis response is what matters. At 45 degrees off-axis the 2226 drops like a stone above 1kHz, and is down (and out as it were) by 16dB at 1.5kHz. [quote]I checked, and the 2226H is actually a current model.[/quote]Still in production, but hardly current. The telling point is that JBL no longer uses it in their current pro-sound cabinet offerings. JBLs top of the line drivers have been neo for nigh on a decade, but they are not sold as separate components.

[quote name='Hamster' post='242135' date='Jul 17 2008, 03:48 PM']A tweeter is just a small kind of loudspeaker designed to reproduce higher frequencies. It's personal preference really as to what sound you want. Generally for a brighter sound you need tweeters, for a dub reggae sound you don't. A 12" bass driver won't be that good for anything above 5kHz. Hamster[/quote]A 12 isn't much good above 2kHz, irrespective of what's claimed, as those claims are for on-axis response. Move off-axis by two feet and the high end disappears. The trouble is that tweeters don't go to 2kHz. Most don't go below 4kHz. What you end up with is no mids and a lot of hiss. What works best with a 12 is a midrange that covers up to 5-6kHz or so with uniform off-axis response. But it's a more expensive option, so very few manufacturers offer it.

[quote name='beerdragon' post='241853' date='Jul 17 2008, 11:11 AM']as i said i haven't a clue about this, neither its seems does our keyboard player.[/quote] That's usually a good reason to leave well enough alone. Newbies, speakers and soldering irons are a combination that can lead to blown amps.

[quote name='alexclaber' post='241763' date='Jul 17 2008, 09:01 AM']The 2226H looks more comparable to a 3015LF (though has less Xmax and weighs a lot more) in that the treble extension is very limited and thus really needs a midrange speaker unless you only play dub/reggae. Alex[/quote] +1. As good as the 2226 was when introduced it's day is long over. Consider that even JBL has not used them in their high end products for years. As a standalone driver the 3015 has twice the useable bandwidth, while as a pure woofer the 3015LF at half the weight has twice the displacement limited power input capability. If all you desire is a simple cabinet the horse's mouth can be found at [url="http://www.eminence.com/resources/cabinets.asp"]http://www.eminence.com/resources/cabinets.asp[/url]

[quote name='beerdragon' post='241774' date='Jul 17 2008, 09:21 AM']i was a bit sceptical.[/quote] As well you should be. It's not possible to rewire a 4 ohm 2x10 to 8 ohms. If indeed the meter reading went from 4 to 8 ohms it could only do so if one of the drivers was disconnected. BTW, a meter would not read either 4 or 8 ohms, as it measures the voice coil resistance, not impedance. The DCR measurement is on average .7 the impedance. I assume you took that into consideraton with your results.

[quote name='phatbass787' post='204501' date='May 22 2008, 02:17 PM']Yup good idea, the superfly 48 cab does the same thing it has 2 x 4 ohm inputs, so full power into one little cab! So you can take one cab to the gig![/quote] Perfectly logical, assuming that a 4x10 can actually make use of more than 500 watts. AFAIK none can. Most can't make use of more than 200 watts, so powering them with 500 is more than adequate. The number of cabs of any configuration that can make use of more than 500 watts can probably be counted on one's fingers.

Buy two Neutrik Speakon connectors and the length of 14 ga (2mm) wire you desire and assemble it yourself, no soldering required.

[quote name='lowhand_mike' post='236402' date='Jul 10 2008, 07:05 AM']so how can you tell what the drivers are? say for example you take the drivers out of my ashdown, they have their own drivers in there but it says very little on the back of the magnet casing. all i know is the ohms and watts and size[/quote] Aye, there's the rub...which is why replacing drivers is best left to experts. Catch 22: Anyone expert enough to do so would not be using a store bought cab to begin with. So all things considered, if you don't care for how your cab sounds the most logical route is to find one that you do like. Or roll the dice and hope for the best.

[quote name='thinman' post='236082' date='Jul 9 2008, 04:23 PM']It's a bit more complex than just volume though - if you have ports, which many bass cabs do, their diameter and length are part of the cab tuning and that may affect driver choice too. Hopefully Messrs Claber or Fitzmaurice will be along to give a definitive answer here. Of course, you might strike lucky with a randomly or inexactly chosen driver but on the other hand you might waste your money! If you're going to fork out on an expensive driver like an Eminence Deltalite or the like then build a BFM cab around it - it'll probably be better than the cab the drivers were intended for anyway and a butchered "name" cab will probably be devalued.[/quote]The only way to know whether new drivers will be an improvement is by knowing what's in there now, then comparing the two. Unless the originals are absolute junk you may find there's little, if any, benefit in changing them. OTOH many OEM drivers are junk.

[quote name='TheRinser' post='232976' date='Jul 4 2008, 07:56 PM']How do I go about testing the bad driver? All I can tell you is what it sounds like now. If it would help I could get an audio file of what it sounds like uploaded. Think they must be wired in parallel then, because the 2nd driver in the chain, wiring wise, works fine. Would this be right? The wires run from the crossover to the knackered speaker, then on to the one that's still working fine. Cheers, Tom[/quote]Touch a 9 volt battery to the terminals of the exposed speaker cable end, both cones should move. You could use one of the recommended drivers for now, replace the second when funds permit. I wouldn't invest in another Peavey, it's not a good driver. I believe Blue Aran is a good source for Eminence.

[quote name='TheRinser' post='232883' date='Jul 4 2008, 02:42 PM']Xmax(mm): 2.5[/quote] Ouch. That puts this bugger in the same class as that Celestion. It will only take 25 -30 watts thoughout most of the bass power band before running out of excursion. Its sensitivity is rather pitiful also. I wouldn't bother to get a matching driver, I'd toss both of them. The Eminence Beta 10 and Basslite S2010 have specs close enough to work in the same cab. Of those the S2010, despite a lower power rating, will actually take more power. Four ohms is not an option for either, so if you must have an 8 ohm cab find the Beta 10b version, which is 16 ohms, wire the pair parallel for an 8 ohm load. BTW, have you actually tested the bad driver? If they are two 4 ohm drivers series wired for an 8 ohm cab an open voice coil in the one would prevent both from working.

[quote name='TheRinser' post='232843' date='Jul 4 2008, 12:30 PM'][url="http://www.loudspeaker.co.uk/bl10-200.htm"]http://www.loudspeaker.co.uk/bl10-200.htm[/url][/quote] The specs of that driver make it unsuitable for electric bass IMO. [quote]there is this quote about a similar driver( from the talkbass post) "It is nearly identical to an Eminence BP102. The BP102 is a better driver, but it requires a 23% larger volume."[/quote] If it was 'nearly identical' it would use the same box size. Either get a Peavey or find out the Peavey specs and replace it with a driver that matches them precisely.

[quote name='phil_the_bassist' post='232729' date='Jul 4 2008, 09:56 AM']tonight I'm in one of the sh*tty-sounding venues, so i'm gonna get myself into a corner,[/quote] Always remember that where the cab is placed affects the overall room sound, but what you hear is determined by where you're standing in relation to not only the cab but also the room boundaries, the worst culprit being a low ceiling. Where that's the case hearing the low end is often a matter of standing as far away from the cab as possible,

[quote name='phil_the_bassist' post='231494' date='Jul 2 2008, 12:33 PM']I still get problems with the onstage sound, depending on the venue. Is this to do with the proximity of the opposing walls/side walls/ceiling?[/quote] Yes. This explains to some extent what's going on: [url="http://billfitzmaurice.com/phpBB2/viewtopic.php?f=10&t=999"]http://billfitzmaurice.com/phpBB2/viewtopi...?f=10&t=999[/url] Unfortunately there's very little you can do about it. Your options are to adjust your rig for a good sound on stage, or adjust it for a good sound out front, whichever is the more important to you. The only cure is to cover the stage with your rig to your liking, and the house with the PA, assuming you have the PA and a tech who knows how to use it.

[quote name='Krysbass' post='231310' date='Jul 2 2008, 08:48 AM'](I usually have the EQ flat)[/quote] That could be a lot of the problem. I don't know where the current penchant for flat EQ came from, but it serves no purpose IMO. Those knobs are there for a reason, and that's to dial in tone and power. If flat EQ was truly a desirable goal there wouldn't be any need for those knobs. I haven't tested my Fly, and I won't as I don't care, but the vast majority of amps set to 'flat' aren't. They have a built in EQ pre-shape, to make them sound better than they would if they were actually flat.