Bill Fitzmaurice

Glue alone might not hold well. Copydex looks to be a good adhesive, use it to glue a piece of business card over the hole and you should be good for a while, if not permanently. Do remove the driver to do the job, so you can push the bits of cone back into place from the back. From a cosmetic standpoint you could glue the patch to the rear of the cone, so it won't be a visible repair.

It's a phase sourced cancellation caused by the distance between the pickups. The same thing happens with one pickup when it's a humbucker, but at much higher frequencies, as the distance between the coils is so short. That's why a Les Paul or any humbucker equipped guitar doesn't have the highs of a Strat or other single coil pickup guitar.

I did the same to my Superfly shortly after I got it. One reason was to give me a place to put the fan I needed to use to keep it from overheating. It's the same case I previously had my Hartke 3500 mounted in, so I still ended up with a net weight reduction of some 10kg or so.

Whatever is the problem it's inside. It could be anything from power supply caps that are toast to a simple cold solder joint between a component and the PC board. Easy enough to diagnose and fix if you're an experienced tech. If you're not an experienced tech you need to take it to one.

It's this picture that left me shaking my head: Cabs like that are the reason why I started building my own in 1969. There were some very well designed bass cabs back in the day, EV B115M and B215M and the JBL Cabaret series are a couple that come to mind. Nobody bought them, because they were sold as separates, and in those days you always bought the amp and speaker as a set. The largest amp manufacturers were Fender, Marshall and Vox, and their bass offerings were basically guitar amps without reverb or tremolo. The only amp manufacturers from the 60s that were first and foremost electric bass oriented were Ampeg and Sunn, and not coincidentally they had the best bass speakers as well.

Pictures of the 1553 show it to be two tens and a fifteen sharing the same air space, with a port that has no ducting. Even though the drivers all share the same air space the jacks are set up for optional bi-amping. It's the kind of bizarre Mickey Mouse engineering that guitar cabs can get away with, but not bass. As it dates to the early 1980s chances are the drivers are musical instrument rather than true electric bass drivers.

I use Eminence exclusively. My Jack 12 is loaded with a 3012HO, my Jack 15 with a 3015. My Jack 10 PA mains use 2510s and NSD 2005 compression drivers, my T39 subs use 3012LFs. My Wedgehorn 6 floor monitors use Alpha 6s. If I was on your side of the pond where Eminence is more expensive than here I'd probably use European woofers in my PA gear.

You should change the graph scale to show only up to 250Hz, as above that the software isn't accurate. Sensitivity is most important between 50 and 90Hz, as that's where power demands on the amp are highest. Looks good to me. I'd only use it when crossed over to a midrange driver no higher than 2kHz. Maximum SPL is low because it only has a 150w voice coil. For your purposes it would probably suffice. People who like it probably mean that they like it better than the OEM driver they used it to replace, and that's logical, because it's a better driver than most OEM tens. It's not just for PA. As far as that goes the Beyma has specs that are much more PA oriented. That's typical of most European manufacturers. American and British bass drivers, like Eminence, Celestion and Fane, all evolved from guitar drivers. In the 1960s none of them even made real bass drivers, and guitar drivers weren't called guitar drivers, they were all called musical instrument drivers. When bass drivers were created in the 1970s and beyond American and British designers tried to retain as much as possible the midrange response of those earlier musical instrument drivers. European manufacturers didn't have that experience to draw on, nor much in the way of musical instrument OEM business in their home countries, so they went after the PA driver market.

A disconnected driver becomes a passive radiator, upsetting the tuning of the cabinet, which could result in blowing the remaining drivers.

I made my speakers and my bass. My amp is an Ashdown Superfly, which I probably wouldn't recommend to others, as it's very underpowered, but the high sensitivity of my speakers compensates for that.

The thermal power rating and displacement limited power are both considered in the Max SPL chart. So is sensitivity, making it more useful than the maximum power chart. A maximum power of even a thousand watts is of little use if sensitivity is only 85dB. Not considering that is why those who use stereo or auto sound woofers with very high power ratings end up sorely disappointed with the result.

The transfer magnitude chart only considers sensitivity. If you're driving a few watts that's significant, but who does that? The very low end doesn't matter that much, most of what you're after lies in the 60-90Hz pass band. I'd say the Pulse looks to be the best of these three. Try it again with 4o to 45Hz tuning. That rise at 100Hz could result in a bit of boom. I wouldn't stop there, try some more twelves, particularly the Eminence Deltalite II 2512 and Delta Pro 12-450.

Model them all in the same size box, whatever you're comfortable with, and try them with the same tuning. When you model in different size boxes with different tunings you're not comparing the drivers, you're comparing the boxes. The spike around 2.5kHz is the driver break up mode, a bad thing with PA or stereo, but it's what's mainly responsible for what we call an aggressive tone.

I played 70s rock in the 70s, and 60s rock in the 60s for that matter. I have no interest in trying to get the same tone I had then. We bass players were constantly changing amps and speakers as new tech became available, and there was no such thing as gear nostalgia. I finally settled in with my current rig twelve years ago. It does everything I want it to, so I'm done with the hunt for tone nirvana. Even though my tone now bears little resemblance to what it was in 1965 or 1975 it's not the least bit out of place when I play songs from those days. It's better.

In that case model the drivers you're considering paying the most attention to the Maximum SPL chart, which considers sensitivity, thermal power handing and displacement all in one place. Overlay a few drivers, using a different graph color for each. The software is only accurate to perhaps 300Hz, so above that compare the data sheet SPL charts.

If you don't know how to use speaker modeling software don't try to design your own cab. It may look easy, but it's far from that.

Speaker break in is optional. You can use an accelerated method to do it over night, though the neighbors wouldn't take kindly to it, or you can just use it. One or two gigs will get it to its maximum potential. The changes in response are real, so ignore the wags who deny that break in occurs, but they're also slight, so don't expect anything major. Most of what you'll hear is yourself getting used to how it sounds.

The magic is eight tens, not Ampeg. The next best thing is a pair of 2x10 or 2x12, vertically aligned. Half of the 'magic' is a lot of cone area, the other half is having the uppermost drivers up high where you can hear them.

The ground lift wouldn't affect the level. It's only purpose is to prevent ground loop hum.

The total load capacity is 2 ohms. Daisy chaining and individually connecting them to the two outputs is the same, parallel wired, and in both cases the total load is 2 ohms. There is a very slight advantage to connecting them individually, as that way you don't have one cable carrying the current drawn by both cabs. For that advantage to be meaningful your cables would have to be much too long and of too light a gauge.

You can get a Real Time Analyzer app for your phone. It may not be laboratory grade, but it will enable you to make comparisons between different cabs.

Driver manufacturers yes, speaker manufacturers, no. Your plot appears to be that of a raw driver mounted in a wall. What's seen will remain pretty much the same when mounted in an enclosure above roughly 200Hz, but below that where the enclosure is a much responsible for the result as the driver it will be completely different. That same driver in ten different enclosures will have ten different result in the lows. Even without the enclosure information one can tell that it won't do well in the lows, as the impedance plot shows a resonant frequency of 65Hz, which is at the upper end of useful for an electric bass driver. That's to be expected with a driver with that sensitivity.

Not really. Most Eminence drivers have always had a rising sensitivity in the mids, peaking in the 2kHz-3kHz range. They have not changed that with their neos. The same is true of Celestion and Fane. What you are seeing is more use of European brands, like B&C and Faital Pro, which tend to have flatter response, with all their drivers. They're fairly common now, but were hardly ever used in electric bass cabs as recently as fifteen years ago.

None. There are many factors that influence both sensitivity and frequency response. The magnet material is not one of them. By no means are neo magnet drivers or newer design drivers more sensitive. One of the highest sensitivity drivers ever made at 101dB/1watt was the original JBL D-130. It had an AlNico magnet, it was created in 1947, and it wasn't a musical instrument or PA driver, it was originally intended for hi-fi. It also had poor low frequency response, with a 100Hz F3 and 45Hz F10, but in 1947 that was sufficient for the program material that was available.

The answer is complicated, because most of the Thiele/Small specs contribute to the driver sensitivity, as does the enclosure. There's no reason why you'd need a lower sensitivity speaker per se, but by and large what contributes to higher sensitivity also contributes to less low end extension, and vice-versa. For that reason if you see a single driver speaker rated at more than 98dB/1w it probably doesn't go very low. By the same token if a single driver speaker claims to be -3dB at 35Hz it can't have much more than 93dB sensitivity. And lastly, if a small speaker claims both low extension and high sensitivity they are, in a word, lying. It's all summed up by Hoffman's Iron Law.