Bill Fitzmaurice

Schematic_of_SUPERFLY1.pdf

As I said, I'd never seen one, but it's not like I'm shopping cabs. That looks pretty good, and it's correctly configured. At first glance it would appear pricey, but as I said there aren't many eight inch drivers that work well for bass, and those that exist aren't cheap. It looks like it may be loaded with Faital Pro 8PR200, which is a particularly good option.

The usual configuration is paired 2x10 or 2x12 vertically stacked. I haven't seen a pair of 2x8 vertically stacked, but I haven't seen a 2x8 either. As for why vertical stacking works better, the horizontal dispersion angle is inversely proportional to the cab width. It also eliminates high frequency comb filtering across the sound stage.

There are some, though not many, eight inch drivers that work well for bass, and they have the advantage of much better mids. But in terms of midrange dispersion to the audience and the player as well they should be vertically aligned. Using four eights in the usual arrangement would give the worst possible result.

I didn't say they were dishonest, just that they and pretty much every driver manufacturer make recommendations that they probably shouldn't. Putting it in perspective, those drivers would have been state of the art in 1975, when the very notion of an electric bass driver was still new, and for the most part what was available were generic musical instrument drivers that were very much guitar oriented. That was then, this is now, and now if you want a driver that's going to work well in a small cab it's not one with high Fs and short xmax. It will be one with low Fs and long xmax. A necessary trade off when you do that is lower sensitivity, which you need to compensate for with power. That wasn't an option in 1975, when 100 watts was a lot, and if you wanted 300 watts it took an eighty pound SVT to realize. That's not a concern today, when you can get 800 watts from an eight pound amp.

Not all amp send/receives are configured the same. Some have the master volume before the return, some have it after. Only by trying it can you know for sure, assuming you don't have block diagrams for both amps.

63.5 Hz and 62.1 Hz Fs are both too high for electric bass. I've seen dozens of drivers advertised as suitable for electric bass that shouldn't have been. These are two of them.

My assumption is that it's the FTX1225. The TF1225CX is 250w, not 300w, plus the 2.5mm xmax and 63.5 Hz Fs make it unsuitable for electric bass.

If I was in the market for as small and light a cab as possible it would be a 1x10 that doesn't cram the driver into too small a space. I haven't seen dimensions for the GSS 1x12, but the FTX1225 works best in a cab with a net volume between 60 and 100 liters, exclusive of the port and driver. Any smaller than 60 liters will give weak lows and boomy midbass. Also, there's a mistake on the Celestion data sheet. It lists Vas as 12 liters, the actual is 120 liters. As for the Celestion BN12-300S, I would not use it for electric bass. The 62Hz Fs is too high, the 2.5mm Xmax too short. There are many tens that outperform it.

I'd be wary of getting the smallest 1x12" you can find. Search 'Hoffman's Iron Law'.

Clipping can hurt tweeters and midrange drivers, because it increases the midrange and high frequency content to much higher than normal levels. It's the main reason why tweeters in bass cabs fail. It has no more effect on woofers than does water on a duck's back.

There's no reason not to exceed the cab rating. That's only a problem if you run the amp at full tilt, while long before you reach that point the drivers will have run out of excursion and will be sounding quite horrible. A higher amp rating gets you more headroom. In the PA and hi-fi worlds, where clean sound rules, the recommendation is for amp power to be double the speaker rating.

Since the cab on EBay wasn't designed specifically to work with the drivers you are looking at the results will probably be less than optimal at best, and possibly really bad. If you're looking for an inexpensive cab buy used, with C-19 putting everyone out of a gig there's no shortage of used out there.

Make sure it's a fuse, not a bulb. A fuse would normally be in a holder that makes it easy to replace.

I doubt that they're bass drivers, as the magnets don't have pole piece venting. If they were sold as bass drivers it must have been decades ago, before pole piece venting became a standard feature. OP, you've got the cart so far out in front of the horse that it's not even within sight. If you're going to build your own speaker do so using a proven and tested design that leaves nothing to chance.For instance, a cab only 246mm deep won't produce much bass. 400mm is more like it.

True. The current version of the SVT bears no resemblance to the 1969 version, which was loaded with guitar drivers. And who can say anything good about the St. Louis Music version that was made of chip board? 😫

The drivers Ampeg uses for the most part are inexpensive, more or less the equivalent of the Eminence Alpha series, those Barefaced uses are high end, more or less the equivalent of the Eminence Kappalite series. For that reason alone they won't sound alike. Barefaced also uses pretty much cutting edge technology, Ampeg hasn't made a significant change since the 1990s. Both approaches are valid, depending on what you're after.

What I really think wouldn't get pass the word censors. 🙄

Hogwash. Stamped frames aren't unique to Ampeg, and the frames don't move. As to the OP question, it's mainly the amp. Ampeg uses Eminence drivers in simple cabinet designs. That's not exactly unique to Ampeg. The drivers aren't unique either. As is the case with the vast majority of OEM drivers they're quite close to off the shelf retail drivers.

One advantage to having more power than the speakers can handle is clean headroom. Another good reason is because amp manufacturers tend to be, shall we say, optimistic in how much continuous power their amps can actually deliver. As for speaker power ratings, all speakers should have two sets of numbers, thermal and mechanical. Those companies that do provide mechanical power ratings are, unfortunately, very rare exceptions. Never forget that truth in advertising is an oxymoron, and always has been. The phrase 'caveat emptor', after all, was coined when Latin was still a living language.

Using identical 8 ohm drivers the 2x10 is 4 ohms and the 4x10 is 8 ohms. In that case 600w into the 2x10 could be some 6dB louder than 400w into the 4x10. That's because in the 2x10 each driver will be receiving 48 volts, in the 4x10 each driver will be receiving 28 volts. The 4x10 would equal the 2x10 if the drivers were all parallel wired, but that would take a 2 ohm capable amp. But this is academic, due to the displacement limited power handling of the drivers. Very few tens can take 300w, and those which can tend to be PA subs. Electric bass tens tend to be displacement limited to 100 watts, in which case you wouldn't be able to put 600w into the 2x10, and by dint of that the 4x10 would go louder.

That's weird. Amps parts resonating to specific notes tends not to happen with amps, as the parts are too small relative to the wavelengths involved. If it was mine I'd take it out of the case and remove the cover, then send it a signal from a sine wave generator, sweeping the frequency until the rattling is heard. Then I'd use high temperature silicone sealant to stabilize whatever is vibrating.

If you liked that consider this: If a man is walking through the woods and says something, and there's no woman there to hear him, is he still wrong?

With no change to the amp volume two speakers parallel wired get a 6dB increase over one. That's because the voltage into each speaker is the same as that into one. The effect is the same as it would be if you doubled the voltage into one speaker. If you double the power into one speaker that's 3dB, but when you double the voltage you quadruple the power.

Whatever the noise is coming from it can't rattle unless it's being vibrated. The source of that vibration would likely be the cab, which would only vibrate if insufficiently braced inside. I'd fix that, because cab panels that vibrate result in a loss of acoustical output. If you want to settle for fixing the symptom rather than the cause a piece of yoga mat foam between the cab and amp should do the trick.