Cab - Question - crossover/ disconnecting horn

[hamfist]

OK, my question is about my GK 212 neo II cab.

If I merely turn the tweeter control on the rear to minimum (at which point I can perceive no sound coming out of the horn), is that the same as actually disconnecting any crossover inside and wiring the woofers straight to the input ?

I assume there is a crossover inside which splits my signal into high and low frequencies, and sends the high to the horn, and the lows to the woofers. I have no idea of the crossover frequency in my cab as GK publish no info about this. My suspicion is that this frequency is significantly lower than the woofer's upper frequency output abilities.

With the horn turned down on the rear and the signal being split by the crossover, am I right in assuming that the woofers don't receive a full range signal, therefore possibly sounding duller than if just connected them straight to the input, as I guess that the woofers are capable of giving out reasonable amounts of sound at frequencies higher than the crossover allows them to have in "normal" operation.

I hope my waffle is understandable. The thing is, with the horn completely turned down, the tone is too bassy for my tastes. Howewer, I'm suspicious that these woofers might be capable of putting out a brighter tone, if fed the full range signal from the amp.

Edited February 27, 2013 by hamfist

[stevie]

Yes, it’s quite clear what you mean, hamfist. I can’t give you a definitive answer on this but I can tell you how to find out. All of the bass cabs with tweeters I've examined so far have crossover components on the tweeter but nothing on the bass. The bass unit is normally wired directly to the input and in theory rolls off naturally where the tweeter rolls in. So the chances are that what you are hearing from the bass units is what they actually sound like full range: you’re unlikely to get any more treble out of them.

I can’t be 100% sure because I’ve never looked inside your cab. If you want to take a look inside, trace the wires from the input to the bass units. If there is an inductor (coiled enameled copper wire) at some point in the circuit you should simple bridge it with a piece of wire to take it out of circuit (solder for a permanent job). That will make the bass units brighter. Make sure the inductor is connected in series with the bass units though. There is likely to be an inductor across the tweeter: bridge that and you could be in trouble.

In the extremely unlikely event that there is a coil *and* a cap on the bass units you will need to disconnect the cap as well. I’m just covering all eventualities – I don’t think you’ll find one.

[Bill Fitzmaurice]

[quote name='hamfist' timestamp='1361990753' post='1994150']
If I merely turn the tweeter control on the rear to minimum (at which point I can perceive no sound coming out of the horn), is that the same as actually disconnecting any crossover inside and wiring the woofers straight to the input ?[/quote]No.

[quote]I assume there is a crossover inside which splits my signal into high and low frequencies, and sends the high to the horn, and the lows to the woofers. I have no idea of the crossover frequency in my cab as GK publish no info about this. My suspicion is that this frequency is significantly lower than the woofer's upper frequency output abilities[/quote]
In most cases the opposite is true, they go to the tweeter an octave or so higher than where the woofer is useful. 4 to 5kHz is the usual range. That leaves a gaping hole in the response, and it's why midrange drivers should be used, at the least in concert with tweeters, if not replacing them.

[quote]With the horn turned down on the rear and the signal being split by the crossover, am I right in assuming that the woofers don't receive a full range signal, therefore possibly sounding duller than if just connected them straight to the input[/quote]Probably not, see above. And even in those rare cases where a twelve has useful axial response above 3kHz none have useful off-axis response above 2kHz.


[quote]I hope my waffle is understandable. The thing is, with the horn completely turned down, the tone is too bassy for my tastes
[/quote]Don't turn it completely down. Use your amp EQ to control the highs.

[Mr. Foxen]

Chances are the tweeter is just high passed and attenuated and doesn't have a crossover at all, so the woofers get full range signal, minus whatever is tapped off by the tweeter, which probably won't be anything audible. Disregard if you know there is an actual crossover in that particular cab.

[hamfist]

[quote name='Bill Fitzmaurice' timestamp='1361996111' post='1994277']

Don't turn it completely down. Use your amp EQ to control the highs.
[/quote]

Yes, that's how I'm working it at the moment.

And thanks to all for your comments everyone. I haven't actually taken the thing apart yet, as it seems like a bit of a performance to do so, but I guess I should do. Might also throw off an email to GK about it.

And, Bill, to pick up your point about midrange drivers, my next cab will definately have one. I just don't understand why they are not standard on bass cabs, even instead of a tweeter. It's down to cost and tradition I expect.

[Bill Fitzmaurice]

[quote name='hamfist' timestamp='1362040160' post='1994748']
And, Bill, to pick up your point about midrange drivers, my next cab will definately have one. I just don't understand why they are not standard on bass cabs, even instead of a tweeter. It's down to cost and tradition I expect.
[/quote]Tradition and cost. The first tweeters used were piezos, back around 1972. They were stuck in bass cabs because they were cheap and didn't need a crossover. Midranges weren't used because few existed capable of the job, and they required crossovers. Eventually dynamic tweeters with high pass filters, if not full blown crossovers, supplanted piezos, but midranges cost roughly twice as much, so they're seldom employed. The midranges we have at our disposal today render tweeters obsolete, but I wouldn't count on seeing them go away anytime soon.

Edited February 28, 2013 by Bill Fitzmaurice

[hamfist]

[quote name='Bill Fitzmaurice' timestamp='1362060844' post='1995144']
Tradition and cost. The first tweeters used were piezos, back around 1972. They were stuck in bass cabs because they were cheap and didn't need a crossover. Midranges weren't used because few existed capable of the job, and they required crossovers. Eventually dynamic tweeters with high pass filters, if not full blown crossovers, supplanted piezos, but midranges cost roughly twice as much, so they're seldom employed. The midranges we have at our disposal today render tweeters obsolete, but I wouldn't count on seeing them go away anytime soon.
[/quote]

Thanks Bill, I thought as much. Anyway, for me it's problem solved, as I will be in recept of two Baer ML112 cabs tommorow !