Bill Fitzmaurice

[quote name='neilb' post='360305' date='Dec 21 2008, 11:24 AM']No, I dont work for BOSE before you ask!![/quote] Maybe not, but one of their shills will quite possibly show up post-haste, as they have their employees use search engines to find threads like this one to weigh in with less than objective opinions. The Bose is adequate for bass, but is no better than a 2x10 at 1/4 the cost. As for PA, OK for coffee house gigs, but again grossly overpriced, and won't do large rooms.

[quote name='bumnote' post='359849' date='Dec 20 2008, 03:20 PM']Few people seem to reccomend celestion, i dont know why. I dont know if emminence with their bigger market produce better quality or its us brits thinking if it comes from the us its got to be good.[/quote] One reason is that the Orange series have such limited excursion capabilities that they're hardly even useable for bass. Another is that until quite recently even MI-5 couldn't find specs for Celestion. It's similar to the Marshall situation, who are the most identified with Celestion and who also have always been associated with great guitar amps and speakers, but electric bass, not so much.

[quote name='bumnote' post='359208' date='Dec 19 2008, 04:52 PM']Thanks for the clarification I just looked at the spec for the 10 and as you rightly say its a pressed steel chasis £64 for a bass lite 10 and £71 for a deltalite[/quote] Here the S2010 is $70, the 2510 $110. I think I catch the smell of revenue agents mucking up the price structure on your side of the pond. It wasn't for naught that we dumped that boatload of tea into Boston Harbor. The Basslite CA2010 is cast also, but I tend to forget about that one, as it has a rather poor response. The S2010 is the bargain driver here, with the same displacement limited output as the 2510, and almost as good a response, but for only an additional 7 quid for the 2510 I'd be going with it.

[quote name='bumnote' post='359165' date='Dec 19 2008, 04:04 PM']I hesitate to argue with an expert, but the bass lite i bought was not a stamped frame but cast, and the eminence spec describes the basslite as a cast frame aluminium chassis, The price quoted on my local supplier is £101 for a kappalite 3015, £104 for a basslite, and £90 for a deltalite. So far from being less expensive, its actually the most expensive.[/quote] The one cast frame Basslite, the 2515, is built on a Deltalite frame, the rest are stamped. Eminence didn't make any true Basslite 15s because there's not enough demand for electric bass 15s to justify the SKU, so they stuck a 4 ohm coil on a Deltalite 2515 and christened it the Basslite 2515. The higher price of the Basslite isn't warranted, and for it to be more than a Kappalite is just plain silly. Over here the Basslite 2515 is $20 less than the Deltalite 2515. That's not justified either, it just shows that 'instrument' drivers are intrinsically less valuable than pro-sound, even when all that differs is the name.

[quote name='bumnote' post='358847' date='Dec 19 2008, 09:38 AM']emminence produce the basslight, which one would assume to be specially voiced for bass[/quote] The Basslites are less expensive lower power rated stamped frame drivers, as opposed to the cast frame Deltalites and Kappalites. Voicing isn't different.

[quote name='alexclaber' post='352365' date='Dec 12 2008, 02:37 AM']SPL plot for a Schroder 1212R (vs a 2x10" with 2510-II and an SWR Son of Bertha). Note that the SPL isn't referenced to 1W but it gives an idea of frequency response: Alex[/quote]It's very difficult to see the 1212 trace (green). On close examination you see that the 1212 doesn't have more bass response or sensitivity than the others. It has a very much scooped mid response, and less sensitivity below 80Hz, where real bass lies. It does have higher sensitivity in the midbass around 100Hz, where the ear is far more sensitive than in the low bass, The sum total of these gives the subjective impression that it's louder than the others. But it isn't. There are no exceptions to Hoffman's Iron Law on display here.

[quote name='MythSte' post='352351' date='Dec 11 2008, 09:04 PM']I have owned an omni 10.5 and a Schroder 1212R - And listened to my schroder 1212R A/B'd against an omni 10, so i think im in a position to be of some use! (for once...? ) anyway, i actually think you'll be really disappointed if you switch from the schroeder. Stephen[/quote]Agreed, the O10.5 is just too small to get the kind of bottom from one ten that the Schro does with two twelves. Now I can't compare it directly to the 1212, but I do know that the DR250 does get more from one ten than a full size O10 does from two. 9mm will work with a second set of horn braces to further stiffen the sides. Manufacturer's sensitivity figures are worthless as they are not back up by SPL charts to show what the full bandwidth sensitivity is, as opposed to just one (most flattering) point out of over 30.

[quote name='Happy Jack' post='345394' date='Dec 4 2008, 08:57 AM']If I post a simple question, could everyone please refrain from responding "Read the WIKI" or "Google It"? If I want to run a 4-Ohm Eden head through two 8-Ohm Eden speakers, a 115 and a 210, exactly how do I set about introducing a crossover, what sort of crossover should it be, where should it sit in the rig and/or signal chain, and will I really hear the difference? OK, it's a LONG question, but it's still simple, OK? Ta very muchly. [/quote]You either need to install a passive crossover between the amp and the cabs or use an active crossover and bi-amp. You might not hear all that much difference, with commercial cabs it's probably more trouble than it's worth. The main benefit to a crossover is that by removing the low frequencies from the top cab that top cab can be reduced in size by about 75%. It also allows using smaller drivers in the top cab, eights or even sixes, which have far better mids and highs than tens. Doing it right requires that the system be configured as a system from the ground up.

[quote name='bassman2790' post='342585' date='Dec 1 2008, 08:11 PM']I've found in the past that unless you have some form of active crossover, plugging a 1x15 and a 4x10 into the outputs of your amp results in the 4x10 blasting out and the 1x15 being barely audible and to be quite honest, you get little if any (depending on the cab) extra bottom end using a 1x15 with a 4x10[/quote]More to the point, the reason for using four tens is to get adequate bottom. If you have a fifteen providing the bottom then even two tens is more than enough to handle the frequency range where they work best. The optimal arrangement would be a 1x15 on the bottom and a 1x10 on the top, using either a passive or active crossover to assign bandwidths.

[quote name='Sharkfinger' post='342686' date='Dec 2 2008, 04:50 AM']The current covers are made from a tough, rubberised (on the outside) material. Anyone know where I can buy this stuff from?[/quote]The technical term for that stuff is reinforced vinyl fabric, and can usually be found in fabric stores, especially those that sell materials for upholstery.

[quote name='Stag' post='336759' date='Nov 25 2008, 06:25 PM']Seems odd to make them like that if you could make them all at 8ohm and everyone would be as happy as[/quote]+1, but then you'd have incessant whining from those who don't know any better that they must have a 4 ohm cab 'so I can get all the watts out of my amp'. Damned if you do, damned if you don't.

[quote name='andrewrx7' post='329719' date='Nov 15 2008, 11:43 AM']Thanks for any clarification or advice! Andrew[/quote] It's the rare cab that can actually make use of more than half the power it's rated for, so as long as your amp is rated for at least half the sum total power that your cabs are it's enough to drive them to full output. Having more power is a good thing, as more headroom means less stress on the amp and less potential for distortion, but it won't result in more output, so don't lose sleep over it.

[quote name='skankdelvar' post='326451' date='Nov 10 2008, 08:48 PM']Er...if there's no info, what if it's 2 or 4 ohms and he's running it off an 8 ohm output? Always thought that was a no-no? [/quote] I'm not aware of any 2 ohm cabs, and valve amps aren't bothered by lower loads than the tap rating, only higher loads. But in any event he asked about power, not impedance.

[quote name='markytbass' post='326326' date='Nov 10 2008, 04:52 PM']but what if it isn't?[/quote]Use it and don't worry about it. You'll hear it farting out from overexcursion long before you approach its limits, if it does, turn it down.

[quote name='alexclaber' post='318964' date='Oct 31 2008, 08:31 AM']Clipping can cause tweeters to be overpowered and thus damaged. It is unlikely to damage woofers unless your amp has a much higher power output than your speakers are rated or your are pushing the amp so hard that there are no dynamics and the tone is constantly overdriven andh heavily compressed. Pushing an amp into extreme clipping will not damage the amp - that's what guitar amps spend most of their lives doing! Alex[/quote]+1. Guitar amps don't use clip lamps as they'd never be off.

[quote name='escholl' post='314929' date='Oct 26 2008, 06:16 AM']surely it's some sort of false advertising?[/quote]False advertising of this cab's capabilities wouldn't be a first for AG. All of their claimed cabinet responses are way over the top, while their 'AccuSwitch' that claimed the ability to switch between 4 and 8 ohm impedance was proven to be snake-oil. Unfortunately for every person who says that AG's claims are at the least dubious, if not patently false, two more will say 'we don't care, it's the tone that counts'. It would be unfair, however, to single out AG for making claims that don't hold water; the practice is common throughout the industry.

[quote name='KiLLaGoD' post='314511' date='Oct 25 2008, 09:19 AM']Maybe I've got the wrong idea here but I've always been told that where possible you should use a power amp matched to the speaker cabs wattage exactly.[/quote] Been told by whom? Certainly not a quailfied engineer. Anywhere from a 2:1 to a 1:2 amp power to speaker power rating is well within the useble range in most cases. A 2:1 amp power to speaker power ratio won't hurt speakers, assuming one has enough sense to turn the volume control down if the speakers distort, while a 1:2 ratio is usually adequate to drive the speakers to their full output capacity, as that capacity is determined by the excursion limit of the cones, not the thermal power rating. The only immutable rule is that there is no immutable rule.

This is the source of the controversy: [url="http://www.jblpro.com/pub/technote/lowpower.pdf"]http://www.jblpro.com/pub/technote/lowpower.pdf[/url] Those who actually comprehend the Queen's English will note that the underpowering caveat applies only to 'High Frequency Components', ie., tweeters. Those who do not have completely subverted the intent of the document, arriving at the conclusion posted on the Sweetwater site.

[quote name='Mr. Foxen' post='310797' date='Oct 20 2008, 04:15 PM']Occurred to me that the speaker is effectively in a very small enclosure of its own.[/quote]It's for reactance annulling. [quote]Exactly, I was making the point that just because something is old-fashioned or lo-fi doesn't make it no good.[/quote]No argument, my point is that this old behemoth can be beat. and seriously so, by a modern cab literally half its size and weight. Restoring it is like restoring a 50 year old luxury car that gets 10 miles to the gallon. There is value in so doing, but from the standpoint of practicality you wouldn't want to use it for your primary mode of transport.

[quote name='Thunderhead' post='310536' date='Oct 20 2008, 10:56 AM']so you probably shouldn't spend too much time trying to analyse it.[/quote]Or salvage it, except possibly for sentimental value. The number of things wrong with that horn design far exceed the number of things about it that are correct. Circa 1970 it was a fine cab, as the driver technology of that time was so primitive by today's standards that even a mediocre horn was far better than everything else then available. But modern driver technology and advances in both horn design and direct radiating cabinet design have relegated it to curiousity status.

[quote name='Thunderhead' post='309962' date='Oct 19 2008, 01:26 PM']Up-rate the bass drivers so they can take anything the amp can throw at them, even distorted. Yes, I know you're not supposed to distort a PA, and NORMALLY (assuming an intelligent sound engineer) it's actually safer to use less speaker capability than the amp can deliver so the amp doesn't get driven into distortion... but that relies on the sound engineer actually listening for the distortion and not doing it! If musicians are in control, you need to assume the worst . Pick bass drivers which can handle more than double the RMS power of the amp (per channel) - preferably even more - and if possible use one impedance step above the amp's minimum load too, so it cannot deliver as much power - ie use 8-ohm speakers if the amp can drive 4 ohms per channel, or two 16s if it's a mono amp with a 4-ohm minimum load... these are harder to find in PA type speakers though. Yes, this does reduce the efficiency of the system and you won't get as much volume as you think it should be capable of... that's the idea! If it matters, I've also done a lot of repair work for rehearsal studios over the years and this is the only guaranteed way to prevent damage, both for instrument amps as well as PA cabs. If you deliberately under-load the amp, you'll also help prevent power stage damage too. (Don't do this with valve guitar amps though, they don't like to be underloaded.) If this is not what they want to do (high-powered drivers are more expensive), you may need to modify the amps so there is a signal level pad (fitted internally) between the preamp and the power amp - this will stop the amp reaching full power if you arrange it so the preamp goes into distortion earlier than the power amp. This is a simple kind of brick-wall limiter, really. With all these methods you may still need to increase the protection on the tweeters too, since reducing the volume of the amp and making it distort sooner will still have the usual effect. Increasing the value and power handling of the crossover resistor will help - it will also reduce the HF response of the cabs which is probably an advantage in helping with feedback in confined spaces. As you can guess we are not talking ideal solutions for great performance and sound quality here . Just over-engineering to the point it's difficult to break things .[/quote] That seems an awful lot to go through when a $100 limiter is all that's required. As far as using lower powered amps goes, that invites overdriving them to clipping, and clipping has the nasty habit of taking out tweeters, even when they're supposedly protected. Another tried and true remedy is a hefty damage deposit. Abuse is far less likely to occur when there's a penalty for doing damage.

[quote name='tempo' post='309688' date='Oct 19 2008, 05:21 AM']Would a hi-pass filter not help?[/quote] Yes, it would, and for that reason it should be standard equipment. But it won't prevent overpowering of the drivers.

[quote name='Subthumper' post='309583' date='Oct 18 2008, 06:48 PM']Is a fuse sufficient? Or is there a way other than using an amp with a self limiting system?[/quote] Fuses don't work. A brickwall limiter set so that the amp cannot deliver too much power no matter what is the only foolproof protection.

[quote name='escholl' post='300756' date='Oct 6 2008, 02:39 PM']so basically where the others would have a dip in frequency response around 70-80 Hz, as limited by their power handling at that frequency, the one modeled in red doesn't, and it additionally has a significantly better output down to around 40 Hz...with the end result being a broader, smoother frequency response at high output? or something?[/quote] Pretty much. The other boxes all have limited output capabilities at the frequency where the dip appears, and in the low end, but that will not show up on a standard small signal SPL chart.

[quote name='escholl' post='299994' date='Oct 5 2008, 12:24 PM']Say the cab could put out 128dB at 100 Hz, and 136 dB at 1kHz (as an example)....but due the varying sensitivity with frequency range of whatever particular driver, it may reach that 136 dB with only 500 watts of power, but need 2 kW to reach 128dB at 100 Hz....or something along those lines.[/quote]A dilemma indeed, and a very real one, until you realize that differential is only 6dB, and that's on average a quarter turn of an EQ knob. EQ makes it possible to get pretty much anything you want out of a cab, so long as the cab has the ability to make use of the power that EQing results in giving it. In any event, you'll sooner see a man on Mars than you will frequency response or maximum SPL charts from the manufacturers.