Laney CUB12R speaker question

[marcovox]

I've just put an Eminence Legend GB128 in a 1x12 cab to compare it with the Celestion Rocket that the Laney CUB12R comes with.

I liked the change of tone - it was more transparent, with more definition and sparkle, I heard more of my guitar. It was also less boxy, but this is probaly because the 1x12 cab is 30% than the CUB's

Now for the puzzle - both the Rocket and the GB128 are 12", 50W, 8 Ohm speakers. The GB128 sensitivity is 101 dB compared to the 95 dB of the Rocket and yet the GB128 is quite a bit quieter

What could be going on?

[Voxman]

That most definitely sounds wrong - with a 6dB difference, you should be hearing a big increase in volume. I replaced the Rocket 50 with a Vintage 30 (100dB) and the volume increase was huge.

Are you sure the speaker is definitely 8 Ohm & not 16 Ohm and have you checked the connectors? I'd also check that you haven't blown a power tube. Oh, & the obvious one - you're not using the 1w input & comparing it to the 15w input with the Rocket 50?

Just can't think of anything else, other than (possibly) the speaker is faulty.

[marcovox]

OK, update - the lead between the Cub and the cab was crap. I put in another, shorter one and the cab is now louder, but not lots louder. I'm using a guitar cable to the speaker because I haven't got a kosher speaker cable, but I'm not driving it that hard

All the other points you mentioned aren't applicable here

The only true test would be to put the GB128 right in the Cub, but I wanted to avoid that as I'd like to keep it as new and under warranty

Does the quality of the cable inside the cab have a great bearing on sound? Would a proper speaker cable cub to cab increase volume?

Cheers

Marco

[Voxman]

Well no wonder!! If you're using a guitar lead that's why!!! You MUST use a non shielded speaker cable. Not only will it sound naff but you can damage your amp and speaker!

[marcovox]

Found this:

"...the fact that a cable is
shielded doesn't have anything to do with whether
it can be used as a speaker cable or not. The main
reason not to use a shielded cable for connecting a
speaker is that the center conductor ("hot lead") in
most shielded cables is very small - 22 or even 24
gauge. If you attempt to put hundreds of watts
through a conductor that small, it will heat up
considerably, maybe enough to melt the insulation
and produce a short. Most amplifiers don't like
running into a short, and the magic smoke tends
to come out of the amp's expensive little parts.
If you could find a shielded cable with a heavy
enough center lead, you could use it with no
problem; most "guitar" cables will not have enough
copper in them to function well in such an application.
Such heavy-gauge shielded cables *do* exist - they're
just not commonly found in music stores."

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I've not been running the amp loud so not many watts. It'll be interesting to see if it's just a power issue or the sound suffers too. I can make up a lead from some chunky cable I've got

The cable inside the cab from socket to speaker is pretty puny though. May as well replace that too

I've read that ordinary electric cable is good too