stevie

[quote name='karlthebassist' post='752069' date='Feb 20 2010, 07:09 PM']I told him about this cab and I'm going to send the actual driver off to him once I get my other cab back for his tech chap to look at. He said that he has only ever had a couple of problems with Aguilar gear in all the time he's dealt them, and for me to have two faults is a bit too much to be a coincidence - to which I agree with him fully. As his expert said, the first cab was definately a fault, but this one... dunno. I'm going to get my amp checked by a pro to make sure its ok.[/quote] But the first faulty speaker had a manufacturing fault - you didn't cause it. It's irrelevant to the current problem and certainly doesn't make it any more likely that you damaged the second one, which is what your dealer seems to be saying. I wouldn't buy that. If you haven't overdriven the speaker (which seems to be the case from what you have said), you should get a warranty replacement. Chin up!

[quote name='RIM Basses' post='751447' date='Feb 19 2010, 11:02 PM']Cheers for that Steve, Ok so how large is a 50 Litre Cab. Im gonna do the whole cab out of 18mm Marine Birch ply.[/quote] The formula for volume in litres is Length x Width x Depth in centimetres, divided by 1000. Internal dimensions, of course. So, you could go for 42 height (dictated by the diameter of the speaker) x 47 wide x 28 deep. That gives you 55 litres and allows a bit for bracing and the driver volume. Adjust the sizes to whatever you prefer. Just avoid making any of the dimensions the same or simple multiples of each other (i.e. 30 and 20) to spread internal standing waves. The worst shape for a speaker cab is a cube. With 18mm ply you probably won't need to brace it, but I'd consider putting two 2-inch deep, side-to-side braces across the longest length of the back panel. The stiffer the back panel, you more 'slam' you get, in my experience.

The prognosis is starting to look a lot better. You need to do one more thing to rule out a damaged coil. (I'm glad you have a multimeter - that certainly simplifies things). It's possible that the coil former has expanded slightly due to excessive heat but that there is still enough gap to allow the coil freedom of movement when it is cold. The scraping and consequent distortion will therefore happen only when the coil is warm. So, allow the speaker to cool down for half a day, then try it. If the distortion starts straight away, your coil is OK. The reason you need to be absolutely sure that the coil has not been fried is that virtually any other fault is covered by warranty. I suspect what has happend is that the glue between the surround and the chassis has failed at the point where you are pressing. The surround is flapping against the chassis here and producing a nasty noise. Whatever is is, your best bet is to make a warranty claim because your speaker almost certainly has a manufacturing defect. It's not quite clear to me whether you bought this cab new, but remember that Eminence in the US offers a 7-year warranty against manufacturing defects. So you should be covered. Let us know how you get on.

I hate to say this, but it does sound like a fried coil. The voice coil former has probably expanded because of excess heat and is rubbing against the centre pole. What happens when you press on the surround is that you push the cone slightly to the side, which twists the voice coil, pulls the bulge away from the centre pole and stops the rubbing. Try pushing the cone in and out by exerting even pressure all round on the cone (i.e. not twisting it at all) to mimic the normal in-out movement of the cone. Listen for scraping behind the centre dome. If you do hear scraping, then the voice coil is on its way out. You have to do this very carefully because you can cause the voice coil to scrape if you twist the cone even slightly. I hope that I'm wrong.

[quote name='velvetkevorkian' post='750719' date='Feb 19 2010, 11:51 AM']...or their wallets... [/quote] Absolutely! [url="http://www.pnas.org/content/105/3/1050.abstract"]http://www.pnas.org/content/105/3/1050.abstract[/url] The authors of this scientific paper (N.B. not an article by a pimply-faced audio journalist) took 20 volunteers and gave them wine without telling them whether the wine they were tasting cost £5 or £100 or something in between. When they were told they were drinking the £100 wine, the fMRI recorded higher levels of activity in the part of the brain associated with pleasure. It didn't make any difference what wine they drank. If they thought they were drinking an expensive wine, the brain automatically registered greater pleasure. I have seen previous scientific research which demonstrated that the power of aspirin to relieve pain increases according to the lavishness of the aspirin pack. That was based on subjective statements, and whilst it was properly conducted and therefore authoritative, this research was based on actual brain scans. The application of this paper to cables, pickups, strings, exotic woods, limited signed editions, and so on, is obvious. The human brain will gain more pleasure from expensive products even when the only difference between them and other products is that they cost a lot more.

This almost disappeared off the radar. Here's the model for the 50-litre sealed cab I recommend you try for the Celestion. Graph 1 shows the response at 1 watt. The blue curve is the Celestion in a 50-litre sealed cab. For comparison, I've included (in green) an Eminence 3015 in a 70-litre reflex cab. There's not really a huge difference between the two. Graph 2 shows how these two cabs compare with a theoretical 400 watts power input. Because it is reflex loaded, the Eminence cab can handle the full 400 watts and will therefore go louder. The Celestion, on the other hand, will only take 200 watts - although adding a second Celestion 15 will make up for the difference. To improve the power handling of the Celestion, you could reflex load it in a larger cab but this will almost certainly produce a boomy and ill-defined bass sound. If you have the choice, I'd suggest you use 15mm birch plywood for this, perhaps with an 18mm front baffle.

Very good, MIJ! Let me just say that sometimes a bit of bah humbug is sorely needed around here! Oh dear, you seem to have dropped your rattle. Allow me

[quote name='Al Heeley' post='750297' date='Feb 18 2010, 10:32 PM']They look like a good quality cable but why swamp us with all this shocking bull?[/quote] Because it allows the cable company to "add value" and so increase its prices and profit margins. When they started out, Chord used to make no-nonsense, well priced cables. Now they sell speaker cables for £1,000 a pair, which gives you an idea of their business model. By the way, virtually none of these cable companies actually makes its own cable or plugs; they just assemble the bits and market them. Any company can assemble a good quality 6m instrument cable and get it to market for around £25 - Neutrik jacks, a proven pro cable like Klotz, Belden, Canare - or even less using a good quality 'no brand' cable. From a performance point of view, there is no point spending much more than this - you're not going to make a better performing cable. If you do want to spend more, your extra money should go into very high build quality and QC, but chances are that what you'll get for your money is audio jewelry and - quite possibly - an inferior cable. When marketing is more important than engineering you get things like Chord's cream outer jacket (I can't think of a worse colour for a cable that's going to spend most of its time on the floor) or the solid core of the Evidence cable, which not only makes the cable stiffer than it needs to be but also makes it much more susceptible to breakage. Much of what is written about 'exotic' cables is written in good faith by people who really believe what they say and are convinced they have actually heard improvements from their expensive bits of wire. Unfortunately, they are often listening with their eyes.

Only guessing, but it sounds like the pickups are wired in series and that changing the wiring to parallel could do the trick for you. It won't cost you anything except a little research and some solder to find out. You can listen to a demonstration of the differences between series and parallel here: [url="http://www.youtube.com/watch?v=67Fo7AKwfA0&feature=related"]http://www.youtube.com/watch?v=67Fo7AKwfA0...feature=related[/url]

[quote name='solofunkyjazz' post='746728' date='Feb 16 2010, 12:03 AM']No, price doesn't come into it, <snip>[/quote] Funny, I thought you said 'decent therefore expensive'.

[quote name='solofunkyjazz' post='746667' date='Feb 15 2010, 11:04 PM']Try a decent and therefore expensive cable first and then say that .[/quote] Would you say that your Evidence cables are better than the Chords because they are more expensive?

Go on, tell us, how much?

The 15" I took out of my ABM Mini 15 was definitely a Sica. It's not surprising that they buy from different speaker manufacturers.

I've just fitted a Badass to my Yamaha, which had a Gotoh on it before. My impression is that it sounds better: punchier, better sustain, fuller - but that could just be wish fulfilment. Human memory being what it is, the only way you can really be sure that there is a difference is if you have two of the same to compare. What I have noticed, however - and I've never heard anyone else mention this - is that I can get the action noticeable lower without buzzing.

[quote name='AlanP2008' post='744727' date='Feb 14 2010, 01:00 PM']That is an interesting point. Is there evidence? Or is this just a gut feeling? (In which case, perhaps we shoud be measuring your gut!) Alan[/quote] Well, there's plenty of information available on the different methods of measuring xmax, all of which shows that the method used by Eminence (which is perfectly valid) produces a bigger figure than the one used by Celestion. However, there is no simple formula for converting one to the other. If the manufacturer doesn't supply the information, you have to rely on your gut, I'm afraid. Should you feel like measuring my gut, you're welcome to pop around with your tape measure any time you like.

[quote name='AlanP2008' post='743909' date='Feb 13 2010, 12:40 PM']The Bn15 400x has a stated Xmax of 4mm. That compares very poorly with most of the best (for example) Eminence bass speakers ... The Kappalite 3015 LF has an Xmax of 9.6mm, and an Xlim of 17mm, which is really excellent...[/quote] Alan, you have to be careful here because there are different ways of measuring xmax (a bit like measuring car fuel consumption). Eminence uses the most optimistic method, whilst Celestion uses the most conservative. The difference can sometimes be as much as 100 percent. The 4mm xmax given by Celestion is probably the equivalent of around 6mm in Eminence spec sheets (my gut feeling). Other speaker manufacturers publish different figures for xmax so that you can do a realistic comparison (see the B&C website, for example) but Celestion and Eminence only publish one figure which is not directly comparable.

My initial reaction was the same as those you've received already in this thread, but I've just modeled this driver and it looks surprisingly good in a 50-litre sealed cabinet. It will handle 200 watts down to low E as long as you don't apply bass boost. Alternatively, you could use a 70- or 80 litre cab and keep your options open - sealed or reflex. There are a number of advantages to sealed cabs but nowadays these seem to be outweighed by the need to go loud. I'd be tempted by the 50-litre option myself, but let me know your thoughts and I'll post some cabinet suggestions with graphs for your info.

[quote name='Jateca' post='743984' date='Feb 13 2010, 01:55 PM']Members of Talkbass have been very helpful to me, both now and in the past, why the hostility? And I didn't ignore anything. I've contacted Wembley and been looking into speaker repairs and will report here if I find anything that may be useful to other users (like whether it's more economical to get it repaired or replaced.)[/quote] What hostility? I just have a low opinion of much of what seems to pass for advice on that list. The thread discussing your problem absolutely confirms that. Glad to hear you're looking at the reconing option.

[quote name='AlanP2008' post='742085' date='Feb 11 2010, 01:47 PM']Alternatively, if you could get to Wembley (or some other re-coner) there is every chance that they could work out who actually made it, and source a re-cone kit for it. I seriously doubt that GK actually made that speaker themselves, I'm pretty sure the economies of scale are such that it wouldn't be economically feasible. Alan[/quote] You actually seem to have ignored the best piece of advice you have been given (by Alan). Call Wembley and ignore those 12-year olds on TalkBass.