Faital 15XL1400 for bass?

[Wasnex]

LOL - yeah right. Have I suggested we need a 1.4kw mid?

You should read the spec.s of the woof and mid drivers in question... 111 versus 96 dB sensitivity aint in it.



I think we have a suitable mid driver... I am merely opining that using just one red-lines the part... so use two.

Other well informed persons disagree - and have provided well reasoned argument for why it'll all work out.

Nonetheless, I cringe when the OP's purported laid back / down low playing style is brought up as a design criteria. I would prefer the thing was designed to be resilient for other styles and signal sources that could very likely get fed to the beast in real world use. Beef up that mid section and that cab'd have a shot at getting passed on to the grand kids in working order.

Or just build a sub with $1000 woof and call it sorted.*

YMMV

*Maybe per AH's advice put a label on the back saying "1,000 WATTS MAXIMUM INPUT"

I should be obvious from my posts that I have read the specs of the woofer and mid driver. @agedhorse has said, the real world sensitivity spec of the 18" is around to 92dB 1W/1m, and I take his world for it. The spec sheet for the 8" says 96.5dB 1W/1m. 111dB 1W/1m is the rating for my big JBL horns.

I don't think the OP is concerned with passing this on to the grand kids. He has some parts laying around and doesn't seem to want to spend a bunch of cash making an unlimited cab.

If this was your project, I would not tell you you were wrong for spec'ing two 8s for the woofer based on the type of abuse you want to plan for.

The OP has a 900W power amp which is below the 1,000W warning label you propose. He's going to be fine with one 8" as long as his crossover and gain staging is setup right...but you definitely need at least two 8's .

 

[Wasnex]

Basically B3 stores way less power (average power RMS) versus F1
Interestingly the loudness level may be perceived quite similar for both notes on the instrument but power wise I'd derate about -6..10 dB for B3.

Conservative consideration.
-6dB equals 1/4 of power

1200 watt / 4 = 300 watts

The power rating for the 8" mid driver equals 200 watts (thermal)

The total signal (bass guitar signal) shall not distort in an audible way so I assume about 9dB crest factor for the signal in real practice.

200 watts RMS thermal power handling of the driver
Signal crest equals ~9dB
Necessary amp power (RMS) to amplify 200 watts RMS with a signal crest of ~9db
~1200 watts (RMS) amp power

edit
we have to consider mechanical power handling, we have to consider thermal power handling, we have to consider power density at distinct bandwidth of interest, we have to consider crest factor of the signal to be amplified, we have to consider provided amp power, we have to consider different sound settings and pedal board effects, we have to consider different power coming along with different notes played on the instrument, we have to consider different music genres, we have to consider that player Jeff does push different amount of power with just the same gear and settings versus Player Jack.
And last but not least we have to consider that Fourier analytics does not tell the whole story cause there is almost always lots of transient noise involved that contributes to sound and feel and power handling demands.

IMO its such a fascinating interaction of very many variables that makes this science unique and, every time very interesting and very fascinating.

Thanks for the correction on the 8s power handling. I didn't see that the 400W is continuous "program", so 200W RMS.

 

[agedhorse]

This thread might be a good indicator that you (as a player) probably would be better served by an engineer who understands the real world metrics of what the numbers really mean and why they may be used or adjusted to fit real world conditions.

Experience doing this hundreds of times, along with the experience of the real world reliability of such designs goes a long way towards the confidence of designing a product that will deliver the performance while holding up to real world use.

The real world marketplace goes a long way towards making a designer put his money where his mouth is, because they will need to do exactly this if they are wrong.

 

[Wasnex]

@Foz , thought you might appreciate this product: BASS VECTOR PRO | ISP TechnologiesISP Technologies