Burning questions...

[dc]

Hi folks.

How can I expect my sound to differ through different speaker configurations, assuming the same speaker? How does an open backed cab, like a combo, compare with a closed cab? And how does 2 speakers compare with one, and four with two?

Also, anyone know the origin of the quad box? Why were four speakers put together, when one would have done?

TIA

[ash]

I suspect quads came about because they suddenly had 100 watt heads and affordable speakers were still only 30W in the late '50s/early '60s. So they made a box with enough speakers to handle the power of the heads.

I read a story recently (on the Ernie Ball History page... look it up, its really good) about how Leo Fender had a similar trouble with his first big amp design. His solution was to go to JBL and have a special 15" speaker designed to take that power safely.

Another thing with a quad is that the box has much more internal volume obviously, but also has a kind of sharing effect between the speakers, so that the quad sounds much fuller than would four 1x12 boxes of the same combined volume.

And similarly, a quad takes up less space and is (in its own way) easier to move around than the four 1x12 cabs that would be required to handle the same power etc.

[dc]

I wondered if the power handling might be the reason.

So, would an open-backed cab with one speaker sound sharper than a closed cabinet?

The reason I ask is I'm setting up a stereo amp system. I've got two identical combo amps and heaps of 12" speakers. My preferred setup, for ease of use, would be to have both heads in one box and then one single 12" box for each amp. I like a cutting sound, I've tried quad boxes and found the sound too muddy.

[ash]

Its an unusual way of describing it, but you perhaps could think of open backs as more cutting. Really they're just less bassy as the lower frequencies coming out the back cancel with those out the front. The trick with open backs is that you can fine tune their response by placing them in a corner and using the sound reflected off the walls to add to the front output.

Maybe the more experienced stage players here can help with that.

Another option is the concept of a detuned cab. basically its a closed back with a big port in the front which acts like an open back, but in phase. These are the kind I like to make. Search London Power or Mad Sound on Google for some of the bollocks spouted by the guys who invented the name.

[dc]

Thanks, I'll check that out

I guess the best thing would be to make some cabinets and try it out.

[Rog]

My experience with open/closed cabs has been that closed seem tighter/focussed (the sound is more of a cone) and open seem looser/less focussed (the sound is sprayed round more) and louder - I guess because I get the reflection from the back walls, as Ash says.

This means I can hear an open backed cab easier on stage and so can everyone else in the band. A closed back cab projects my sound more to the front and can't be as easily heard across stage. IMO - this leads to a louder band, as people turn up to be heard (louder is not necessarily better - balance is more important).

Like you say dc - you could make your cabs so that you could either put a half or full back on them and A/B the buggers.

I for one would love to hear how you find they differ... under identical conditions. Please post your results here.

[ash]

This means I can hear an open backed cab easier on stage and so can everyone else in the band. A closed back cab projects my sound more to the front and can't be as easily heard across stage. IMO - this leads to a louder band, as people turn up to be heard (louder is not necessarily better - balance is more important).

Thats an interesting observation, Rog. I'd never thought of the open back as having a stage-wide monitoring effect. I knew the old 'controls on top' type open back combos were often place at the front of the stage to provide some monitoring (and so the controls were the right way around!), but I hadn't given any thought to the effect in a backline position.

Close back babs can have a diffuser bar place across the front of the speaker holes to reflect some of the treble sideways and even out the spread of sound. Unique's cab that he posted pics of has a horizontal diffuser, although a vertical bar is probably more effective on stage.

[dc]

It may take me a while to make them but I'll try it each way.

I tried the stereo setup at practice yesterday. Great sound, really fills it out. I'm splitting it with my Boss ME50, which has stereo chorus and so on, into two old Rockit 130s. I'd like to find a way to vary the signal more - different sounds into each one, without complicating things too much.

[Rog]

As I recall, the Rockit 130s were quite a good amp - bloody loud for their size! Weren't they Mesa Boogie ripoffs??

[dc]

Yeah, that's it. The loudness is a problem, really, cos they sound really good turned up!

I've had one since new - about 100 years javascript:emoticon(':D')
Very Happy. It's off-white with a cane front, and twenty year-old coffee stains.

Rockit are still around, renting out PAs.

[borge]

I tried the stereo setup at practice yesterday. Great sound, really fills it out. I'm splitting it with my Boss ME50, which has stereo chorus and so on, into two old Rockit 130s.

did you try stereo delay with a really short delay? (10ms from memory) i allmost fell over the first time i did that, it gives the hugest tone. sounds like an identical guitar doubling your every note in absolute perfect time

[dc]

Thanks, I'll try that.