Do 8" and 12" cabs need a crossover?

[dBPete]

Right now I'm running a 1x12" cab. I'm considering getting a 2x8" to pair with it. Do I need to get a crossover or will the natural rolloff of the speakers be sufficient?

[billfitzmaurice]

Originally Posted by dBPete

Do I need to get a crossover

You do if you want the best results. You also want the eights to be midrange drivers, not full range, and for that matter you don't need two eights to go with one twelve. One will suffice. For that matter a six will work better than an eight.

[dBPete]

Only 1 reply??? Really?!?!?

[christw]

I'd reply with some opinion but Bill knows a lot more about this than I do. I'll defer to him.

[GrowlerBox]

Originally Posted by billfitzmaurice

You do if you want the best results. You also want the eights to be midrange drivers, not full range, and for that matter you don't need two eights to go with one twelve. One will suffice. For that matter a six will work better than an eight.

Does this assume that the 12 is, say, a 3012LF in the appropriately tuned box, or would you say the same for a "normal" full range bass cab? I know it wasn't quite the OP's question, but would you still be better off in the latter case with two of the same 112s, both running full-range?

[billfitzmaurice]

Originally Posted by GrowlerBox

Does this assume that the 12 is, say, a 3012LF in the appropriately tuned box, or would you say the same for a "normal" full range bass cab? I know it wasn't quite the OP's question, but would you still be better off in the latter case with two of the same 112s, both running full-range?

If the two cabs are operating in the same bandwidth you're always better off when they're identical. The only valid reason for using different size drivers together is when they're not operating in the same bandwidth, which requires a crossover, and choosing the correct drivers and cabs for them.

[will33]

If you're looking to just hook it all together like a smaller version of 15+210 stack you can do that, assuming your amp is ok with the resulting ohm load of the whole setup. The "proper" and better way to do it would be to biamp 1-12 and 1-8. The "proper" thing to do with a 15 and a 10 would be to biamp or crossover the two speakers as well but plenty of people don't. When you get down to 8" speakers though (loudspeakers in a bass rig), you're talking about things that commonly can't handle a lot of sub-100hz bass stuff so there the crossover becomes even more important just for speaker protection, let alone sounding better.

[GrowlerBox]

Originally Posted by billfitzmaurice

If the two cabs are operating in the same bandwidth you're always better off when they're identical. The only valid reason for using different size drivers together is when they're not operating in the same bandwidth, which requires a crossover, and choosing the correct drivers and cabs for them.

Right, so my underlying point, I guess, is to suggest to the OP that he consider his reasons for wanting the 8s. Does his 112 cabinet really not provide sufficient high end output? Or is he prepared to sacrifice what it does have for, say, the better dispersion characteristics of the 8? I just have the sneaking suspicion that his efforts may not provide the benefits he thinks they will. Of course, depending on his particular cabinet, he may be completely correct.

[will33]

If he's got a 12 that can go deepish and "sound like a 15" in a smaller package, it's going to have to tradeoff high end response in order to do that, hence the 8's providing "punch and clarity".

[dBPete]

Originally Posted by will33

If he's got a 12 that can go deepish and "sound like a 15" in a smaller package, it's going to have to tradeoff high end response in order to do that, hence the 8's providing "punch and clarity".

That's kind of the boat I'm in. My 12 does handle the full range of the bass pretty well aside from the harmonics. (Now someone will probably tell me to use a tweeter.)

[billfitzmaurice]

Originally Posted by will33

If he's got a 12 that can go deepish and "sound like a 15" in a smaller package, it's going to have to tradeoff high end response in order to do that, hence the 8's providing "punch and clarity".

That's fine, so you add a midrange 6 or 8 and a crossover. But not a full range eight.

[dBPete]

Originally Posted by billfitzmaurice

That's fine, so you add a midrange 6 or 8 and a crossover. But not a full range eight.

What about a fullrange 6?

[billfitzmaurice]

Originally Posted by dBPete

What about a fullrange 6?

Not a fullrange anything. If all you need is highs beyond what the twelve will deliver, say above 1.5 kHz, then what you use is a driver designed to give that response above 1.5kHz.