Need advice: replacement 15" speakers

bongomania · #1 10-03-2011, 12:07 PM

I have a pair of Bag End S15B-D's, and I think their drivers are due for retirement--they clip early and often, even at low wattage. The obvious choice is to get replacements directly from Bag End, and I can do that ($310 each plus shipping)--but I figured first I'd ask here if there are any other options I should consider.

The interior dimensions are approx. 16 x26 x20", or roughly 4.8 cu. ft. They have a large rectangular front port that has a plate for sealing it closed, as desired.

The parameter that I value most highly is resistance to farting/clipping/overexcursion. Sure it would be great to have light weight, low cost, full frequency range, high power ratings, etc. etc., but I am willing to compromise or even sacrifice most of those in favor of resistance to farting out.

What do you suggest? And is there any other information I'd need to provide, to get the most useful response?

Thanks!

billfitzmaurice · #2 10-03-2011, 01:32 PM

You need to use a box program like WinISD Alpha Pro to determine driver compatibility with the cab. Beyond that what determines maximum low end capacity is driver xmax. For each doubling of xmax the displacement limited power is quadrupled. What should be needless to say is that xmax and price tend to go hand in hand.

335guy · #3 10-03-2011, 01:47 PM

Hi Bill,

Quote:

For each doubling of xmax the displacement limited power is quadrupled.

Would please explain this in further detail ? I'm not quite understanding it. Thanks.

rpsands · #4 10-03-2011, 02:04 PM

At that box size there are not a lot of 15" woofers that will do a good job full range.

Basslite C2515's would be good if you are OK with dual 4 ohm cabs. Deltalite 2515 II's are the next best option.

If it were me, I would load them both with 3015LFs and then build a 6nm410 top box after Greenboy's design. Those boxes would be just great with 3015LFs.

(figure about 4x as much power handling with 3015LFs vs. either of the lesser eminence models).

billfitzmaurice · #5 10-03-2011, 02:14 PM

Quote:

Originally Posted by 335guy

Hi Bill,

Would please explain this in further detail ? I'm not quite understanding it. Thanks.

Excursion is proportional to the voltage applied. If you double xmax the driver can take twice the voltage. Power increases as the square of the voltage increase, so twice the voltage equals four times the wattage.

craig.p · #6 10-03-2011, 03:08 PM

Bongo, if I were you I'd model that box as ported, not sealed, because to my knowledge there are few if any drivers that will work well in a sealed cab that big, and I suspect even those few that might would offer a very limited top end.

Also, if you're trying to forestall farting out, consider adding a high-pass filter in your signal chain. This is especially important in reflex cabs.

bongomania · #7 10-03-2011, 03:20 PM

I am totally fine with adding a top box for the range above what the 3015LF's can do... good idea.

bongomania · #8 10-03-2011, 03:33 PM

Quote:

Originally Posted by craig.p

... if you're trying to forestall farting out, consider adding a high-pass filter in your signal chain. This is especially important in reflex cabs.

I do use a very steep high-pass at about 30 Hz (the [sfx] Thumpinator)... do you mean like that, or do you mean something higher up, or shallower-slope?

rpsands · #9 10-03-2011, 05:00 PM

The 3015LF is fine with 4.8cf sealed or ported.

My recommendation would be to try a bunch of different top boxes. A 1x12 guitar amp would be worth a shot too.

GB's CBG low pass section from the fEarful Sub in both boxes.

With the thumpinator you should be good to 400w/cab sealed easily.

craig.p · #10 10-03-2011, 05:11 PM

Regarding the Thumpinator, I don't know anything about it, but if it's 3 dB down at 30 Hz, that may or may not suit your eventual configuration. Your WinISD models will tell you where the danger zone begins down low. With a 30 Hz knee point, you may (or may not) have a narrow "window of opportunity" for overexcursion between where the box unloads the specific driver you've chosen for that specific box and the filter's start of effectiveness. You won't know until you begin running models.

1958Bassman · #11 10-03-2011, 05:40 PM

Quote:

Originally Posted by bongomania

I have a pair of Bag End S15B-D's, and I think their drivers are due for retirement--they clip early and often, even at low wattage. The obvious choice is to get replacements directly from Bag End, and I can do that ($310 each plus shipping)--but I figured first I'd ask here if there are any other options I should consider.

The interior dimensions are approx. 16 x26 x20", or roughly 4.8 cu. ft. They have a large rectangular front port that has a plate for sealing it closed, as desired.

The parameter that I value most highly is resistance to farting/clipping/overexcursion. Sure it would be great to have light weight, low cost, full frequency range, high power ratings, etc. etc., but I am willing to compromise or even sacrifice most of those in favor of resistance to farting out.

What do you suggest? And is there any other information I'd need to provide, to get the most useful response?

Thanks!

Speakers don't clip- they rub, buzz, or the excursion exceeds the normal limits because the surround and/or spider has broken down.

Have them reconed. It will avoid your having to find something different that will work in your cabinet and trying to get used to the new sound, which you probably won't like.

rpsands · #12 10-03-2011, 05:50 PM

In this particular instance where your cab is so close to perfect for the optimal alignment for a 3015LF I would say a pox on using the stock 300 dollar driver. It won't hold a candle to the 3015LF in this particular situation.

bongomania · #13 10-03-2011, 06:42 PM

Quote:

Originally Posted by 1958Bassman

Speakers don't clip- they rub, buzz, or the excursion exceeds the normal limits...

When the excursion exceeds its abilities, that is clipping. Buzzing is typically a sign of the speaker not being able to pass the signal cleanly, which again is clipping.

Sartori · #14 10-03-2011, 07:52 PM

Why not just have them reconed?

billfitzmaurice · #15 10-03-2011, 08:40 PM

Quote:

Originally Posted by 1958Bassman

Speakers don't clip-.

They do. When more power is applied than the xmax will allow them to handle in a linear fashion the fundamentals won't go any louder, but the harmonics will. The result is a clipped waveform, which is nothing more than a clean waveform with added harmonic content. Guitar drivers have a very short xmax, so that they'll clip well below their thermal power handling limit.

Quote:

Why not just have them reconed?

That won't give them more xmax.

bongomania · #16 10-03-2011, 09:27 PM

Yeah I just figure if I'm going to put money into the cabs, I'd like to make the most of it-- so if there's any chance of making them even "better" then that's the route I'll take. If it was to turn out that there was no room for improvement, then I'd look at reconing.