Bill Fitzmaurice

Correct. An LPad is a pair of resistors that attenuate a signal while maintaining a constant impedance load, without which a high pass filter won't work. Those resistors can be of set value for a set degree of attenuation, or they may be variable value, for a variable degree of attenuation. They're typically not used to realize flat response. If that was the case they wouldn't have been  used on innumerable hi-fi speakers that had drivers of equal sensitivity for the last 75 odd years. Their primary function is to allow the user to tailor the response of a speaker to their own taste. Some speaker designers use fixed value LPads to match the sensitivity of midrange and high frequency drivers to that of the woofer when they are higher, but more often than not they use variable value. 

And as noted the impedance of the 1/4" output is ten times what it should be. Combine that with the lack of an XLR input on the power amp and what you have is two non-standard devices that doomed any attempt at using them together.

Quite right. I didn't notice that the only way the Sadowsky pre can deliver the required low impedance output is with the XLR output, while the Sumo doesn't have an XLR input, a curious omission. For that matter the high impedance of the Sadowsky 1/4" output is very unusual.

Don't make more of it than you should. All attenuation does is to turn down the tweeter. If a user can't figure that out they should stick to acoustic instruments. 😉

☺️

2 hours ago, Chienmortbb said:

 Your bass and preamp can reduce the treble, so why put an attenuator on the cabinet?

Because the average horn loaded high frequency driver has 10dB higher sensitivity than the average woofer attenuation by one means or another is a necessity. It can be with a variable LPad, or with a fixed value LPad, or with DSP. Yes, the bass and preamp can reduce the treble, but their frequency passbands don't necessarily line up with that of the tweeter. Besides, there's nothing wrong with tweeter attenuation, we've been doing it for a hundred years, so why not?

You won't get a good guitar tone from a bass cab, at least not if you plan to overdrive it. It's tough to beat a Celestion Greenback.

The key word is 'top'. They're made to be used along with a subwoofer. Some are capable enough to replace a bass speaker, but by no means all, and short of trying them you have no way of knowing.

Considering the target audience I'd say the ad is spot on.

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Well bill I'll be eighty in January

I'm 75 but I haven't forgotten what got me started doing this when I was 15, and it wasn't trying to impress my parents.

5 hours ago, BassmanPaul said:

Depending on the sensitivity and frequency response of the added cabinet it possibly could be a downgrade!!

 

True. Just like a box of chocolates when you mix drivers you never know what you're going to get.

If that's too crude you're too old. 😲

The difference between tens and twelves is slight. Just having the combo up on top of the extension will make the high end more obvious. For that matter putting it on a stand would.

Assuming the Silverado Special is a 2x12 I'd get a 4 ohm 2x12 extension.

That's a hi-fi speaker. The main drawback is it has lower sensitivity than a pro-sound speaker, so it won't go as loud with the same amp.

Tell that to Derek Smalls. ☺️

6 hours ago, Yorkshire Bottom End said:

 

So going on what you've said, even with an MXR M81 (which I've ordered to test) I'm not going to drive the Sumo to its full potential?

What are my options then? I thought a decent preamp pedal straight into the power amp would suffice. Seems not with the SBP-1.

Pedals are made to go into bass amps. Rack mount pre-amps are made to go into power amps. I'm sure there are exceptions, but the only way to know if any combination is to make sure that the output voltage of the pedal is at least equal to the required voltage to drive the power amp to full output. Unfortunately neither your SPB-1 nor your GSS provide those specs.

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You could try the SB1 like this and see if the impedance differential makes much difference from the Sumo.

The impedances aren't the problem, it's the output voltage of the pedal and the input voltage sensitivity of the power amp.

The SBP-1 is a floor pedal, not an active bass, but you're on the right track. Floor pedals by and large are gain configured to drive a full on bass amp, not a power amp.

2 hours ago, W1_Pro said:

 I don't know what vehicle you use to gig in, but as you'll know flightcases (or roadcases in American) can be a pain when you try to  put them in a car.

I drive a BMW. How do I load my gear? Very, very carefully.

Create your own riser. A road case for your cab or combo would work well without needing extra pack space.

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the increased low end seemed to be coming from the tops.

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You’d expect to ‘hear’ the bass apparently coming from the tops. Your brain takes the information from your ears and creates the picture of a band playing.

What's happening is that the low frequencies from the subs are not directionally locatable, as their wavelengths are too long compared to the distance between your ears. Really. Binaural hearing allows us to triangulate sound source locations only when the wavelengths are short enough so that the ear/brain can detect the difference in the arrival times at the left versus the right ear. That occurs on average above 100Hz. Since we can't tell where the low frequencies are coming from we take the directional cues from their harmonics, which are coming from the tops. This is what allows us to place subwoofers away from the tops, in both live sound and home theater. My HT folded horn sub sits 30cm to my side in my living room, where it does double duty as a table. My mains are 3 meters in front of me. I cannot tell that the sub is next to me, the bass seems to be coming from the mains, even when movie low frequency sound effects are reaching 120dB. 

1 hour ago, Beedster said:

 

I've been doing some crude bi-amping recently using these two cabs (to all intents a Mesa 1516 albeit in two cab form), a bit of width to the sound field would be fun 

You're getting all the width to the sound field as is possible already. The midrange drivers insure that the upper woofer doesn't go high enough to get beaming from it, bi-amping insures that the lower woofer doesn't go high enough to get beaming from it, and having the midranges vertical insures the widest possible dispersion from them. Plus the tweeter takes over where the midranges start to droop off-axis. The tweeter in the lower box should be shut off.

The port isn't right for sure. A port of that diameter is appropriate for one ten, but not four. That raises the question as to if the cabinet volume is correct. I suspect it's too small. The idea behind this cab is a good one, but the execution appears to be lacking.

Try it. The speaker will distort at levels far below what it would take to damage it. If it does turn it down and/or reduce the bass EQ.

Don't double post. 😒

No one can give a definitive answer without knowing what you have for an amp and cab. I can say that you've fallen into the watts trap. Watts don't determine how loud or low your rig will go, not with respect to the amp, not with respect to the speaker.