Gallien Krueger 700RB and Ωs for an ext.cab

CJThomasNYC · #1 10-14-2011, 08:42 PM

So, I am a new registered member but I've been viewing the talkbass forums for who knows how long... I have a GK 700RB 210 combo unit. I finally need to extend this monster's volume and range with an additional cabinet. This is an older combo so it powers 225W@8Ω and 350@4Ω. I use the bi-amping feature using the speakon connections.

It is hard to find a cabinet at a decent price that can handle over 350 watts. However, there are many single speaker cabs that can do 300W@8Ω.

Can I get away with an extension cab that only handles 300W@8Ω?

If my onboard 210s handle 225W@8Ω are they evenly distributing that wattage at about 112W per speaker? If so, does that mean when adding, say, a 115 cab each speaker would the receive about 116W (3 speakers distributing 350W @ 4Ω). 116W is quite small compared to a handling power of 300W.

To repeat the question, can I get a way with an 8Ω cab that handles 300W with my 700RB/210 combo?

Thanks, any sort of education will be greatly appreciated.

banikek · #2 10-14-2011, 09:19 PM

Short answer - yes it will be fine. You will be doing what almost every bass player does. Use the volume knob and your ears. Turn down if/when things sound distorted or stressed. That will be your rig's "maximum" practical output (in that particular configuration).

FretlessMainly · #3 10-14-2011, 09:26 PM

I don't generally deal with combos, but my understanding is that each cabinet gets more or less half the wattage when you add an extension cabinet. So, assuming your combo is 8Ω, adding an extension cabinet at 8Ω will reduce the overall impedance to 4Ω. The now 350W will be split - 175W to your combo cabinet and 175W to your added on cabinet. No issues whatsoever.

Obviously, the wattage will be more evenly split between the 2 10s in your combo than they will be between the combo and an extension cabinet, but it should be roughly half and half. I don't believe that you should split the wattage between the three speakers; I believe that splitting them between cabinets is closer to the truth - but I'd be glad to learn otherwise if that's the case.

Jeff Scott · #4 10-14-2011, 10:19 PM

Quote:

Originally Posted by FretlessMainly

I believe that splitting them between cabinets is closer to the truth - but I'd be glad to learn otherwise if that's the case.

You are correct; assuming both the combo's speakers (in total) and the extension cabinet are each 8Ω, then the power is divided equally between the two.

CJThomasNYC · #5 10-15-2011, 07:05 AM

Cool. This is all good information. I understand Ωs quite well enough, but when it comes to exact wattage matching, it concerns me that there's not exactly a guide book --- only what you can afford... more W handling=more $$$.

Now, the next question is --- 1x15, 1x12 or 2x12? I need body but still get some rumble.

banikek · #6 10-15-2011, 07:10 AM

I would suggest another GK 210 cabinet. Same speakers you currently have = less problems with speaker mismatching.

CJThomasNYC · #7 10-15-2011, 07:46 AM

Quote:

Originally Posted by banikek

I would suggest another GK 210 cabinet. Same speakers you currently have = less problems with speaker mismatching.

What do you think could happen if I added a 4x10 cab. Will that make the rig louder than a 2x10 ext cab as I'd be pushing more air or will it just have a more full of a sound? I want that full sound and maintain a midrange thickness (I don't really scoop my tone) which leads me to believe I want a 15 or a 12.

I used to have the 210 RBH cab but had to sell it as it couldn't fit in my car for the cross country move. I really did like that cab, once I plugged it into the 700 combo, it pretty much opened the amp up and gave a much more full sound with amazing depth. Made $300 on it.

Now, I'm ready to move on to something that may potentially change the my overall sound compared to a 210. I played a rig with one 15 and loved the tone. I'm pretty sure it was the amp as opposed to just the 15. I understand a 12 is a compromise between 10 and 15. There's so many options with cabs it's hard to pull the trigger, especially if I'm trying to get a deal on ebay, craigslist, etc...

RickenBoogie · #8 10-15-2011, 07:48 AM

Yes, +1 to a matching GK 210. Plenty of info on TB why a matched cab always trumps a mixed pair.

CJThomasNYC · #9 10-15-2011, 07:55 AM

Quote:

Originally Posted by RickenBoogie

Yes, +1 to a matching GK 210. Plenty of info on TB why a matched cab always trumps a mixed pair.

I hear phasing is an issue but it seems that is basically ignored by many many players, even professional players mismatch the cabs (but i'm sure their tech fixes everything). Do players just don't know any better or is it something you may not pick up on if you aren't listening for it?

Bass_Pounder · #10 10-15-2011, 09:57 AM

Quote:

Originally Posted by CJThomasNYC

I hear phasing is an issue but it seems that is basically ignored by many many players, even professional players mismatch the cabs (but i'm sure their tech fixes everything). Do players just don't know any better or is it something you may not pick up on if you aren't listening for it?

There is your answer...................

There is no "tests" involved in making it to the pro level, just talent and alot of luck (sometimes not even talent).

Bass_Pounder · #11 10-15-2011, 10:00 AM

Quote:

Originally Posted by CJThomasNYC

Cool. This is all good information. I understand Ωs quite well enough, but when it comes to exact wattage matching, it concerns me that there's not exactly a guide book --- only what you can afford... more W handling=more $$$.

Now, the next question is --- 1x15, 1x12 or 2x12? I need body but still get some rumble.

Wattage handling figures are also pretty useless, as they are the THERMAL rating for when the coil will melt.

The true limiting factor is excursion (how far the cone can travel), which is usually 1/2 or less the wattage rating depending on how you use your EQ.

CJThomasNYC · #12 10-15-2011, 03:39 PM

Quote:

Originally Posted by Bass_Pounder

Wattage handling figures are also pretty useless, as they are the THERMAL rating for when the coil will melt.

The true limiting factor is excursion (how far the cone can travel), which is usually 1/2 or less the wattage rating depending on how you use your EQ.

I've been reading about excursion on the forum... is there a rating given for excursion or is that just a sort of eyeballing measurement?

CJThomasNYC · #13 10-15-2011, 03:48 PM

Quote:

Originally Posted by Bass_Pounder

There is your answer...................

There is no "tests" involved in making it to the pro level, just talent and alot of luck (sometimes not even talent).

haha, yes. I kind of hate having a combo because it limits me to that setup and speaker config, of course, i could always drop more dime for a new rig and get what I'm truly looking for.... (i.e. separate power amp, 1x15 because I love the sort of vintage flub tone, think Klaus Fluoride of Dead Kennedy's, and an additional 1x15 a lotmore efficient speaker with a horn for more clarity and power) ... in theory it sounds nice, but of course, for my style of playing, i need articulation and tightness. I should find myself some 10's and call it a day.

Is there a significant advantage of 4x10s to go with my 2x10 combo over just another 2x10?

agreatheight · #14 10-15-2011, 03:58 PM

350 watts split between 2 cabs is 175 watts each cab. Finding an extension cab to handle 175 should be a snap. But yes, the matching 2x10 extension should work great.

Bass_Pounder · #15 10-16-2011, 10:48 AM

Quote:

Originally Posted by CJThomasNYC

Is there a significant advantage of 4x10s to go with my 2x10 combo over just another 2x10?

In your case, no.

Since your amp will only handle a 4 ohm load, you need another 8 ohm cab.

The power from your head will be equally distributed between the cabs (50% power each).

If you use a 4X10, then there will be a mismatch of power being delivered to the speakers within the cab (the speakers in your 2X10 will be getting twice the power as the speakers in the 4X10).

CJThomasNYC · #16 10-17-2011, 08:12 AM

Quote:

Originally Posted by Bass_Pounder

In your case, no.

Since your amp will only handle a 4 ohm load, you need another 8 ohm cab.

The power from your head will be equally distributed between the cabs (50% power each).

If you use a 4X10, then there will be a mismatch of power being delivered to the speakers within the cab (the speakers in your 2X10 will be getting twice the power as the speakers in the 4X10).

Good to know, thank you for the straight talk. I'll stick with a 2x10. If I have the chance to record, maybe then I will decide upon a different configuration if need be (i wouldn't mind a track or two with bass on a 15 only).