GK 800RB with 2-15's (biamp content)

gustobassman · #1 11-07-2011, 11:58 AM

So recently i scored a couple of killer pre-washburn era Eden 15's, a D115 (no tweeter, 200 watt) and a D115XLT (Thanks Tb'er DMK!!! tweeter, 400watt). I have owned an 800RB for years but have only ran it through 810 and 610 cabs. I am not familiar with bi-amping, but heck let's give it a shot.

I ran the D115 to the highs and the D115XLT for the lows.

I must say i'm very happy. I didn't want to send both speakers to the lows because one is a 200 watt speaker and the other is 400 watts so i figured there might be some weird mismatched power dispersion. I'm really not familiar with the crossover, but it seems to sound really good when set at about 11 o'clock.

Any reasons why this won't work? am i in any danger of putting a strain on the D115 because it's only receiving a 100 watt load? I have read through a lot of the mismatched cab threads, but i didn't really see much information regarding this type of setup. Any info would be appreciated!

BillyB_from_LZ · #2 11-07-2011, 12:37 PM

As long as the 15 connected to the 100 watt amp is an 8 ohm speaker, there's nothing to be worried about.

Personally, I'd run 'em both full range first and listen to how that sounds, then mess with the crossover if you're so inclined.

If both cabinets are rated 8 ohms, the 300 watt amp is only rated 200 watts into 8 ohms, so the volume difference will be hard to detect.

husky123 · #3 11-07-2011, 12:42 PM

You are running a very similar setup as my own. I have my 800RB biamped into (2) Shroeder 15's. I also have my crossover at about 11 o'clock and found this gives me the best tone. I tend to run both amps on the RB about the same volume maybe with the high a tad lower. I really don't have to crank it much to get the volume I need vs. running it full range.

I just messed with the biamp thing a week or so ago. I had been running it full range and thought that was the way to go. I'm SOOOO glad I pushed that little button! I'm getting much better tone now. I haven't been this happy with my tone since I parked the SVT. The mids now just pop out so effortlessly. I have always run my GK amps with a slight boost in the mids but I run the EQ pretty much flat now. FYI I also have me tweeters turned completely off. Couldn't be happier.

Just make sure the cab connected to your 100W amp is 8 ohm. The low amp can take 4 ohms so you can run (2) 8 ohms or (1) 4 ohm.

gustobassman · #4 11-07-2011, 12:58 PM

Thanks for the replies! Both cabs are 8ohm cabs. Billy B, i haven't tried both at full range yet. I know the 800RB isn't that high-powered of a head, but the power handling difference between the 2 seemed (to me at least) to be a bad idea if i ran them together. I could be totally wrong!

Husky, i do the same as far as settings. basically flat with some mid bump. However i was running a BDDI into the 800RB with my 610, that was where i got most of my tone from. I have not yet used the BDDI with the Edens because i got a great tone from them alone.

Are you sure about the lower amp being able to handle 4 ohms along with an 8 ohm load in the highs? I could've sworn it's 8+8 = 4 and that both amps were 8ohm, but that running an 8ohm on top and an 8ohm on bottom gave me the 4 ohm load. I've honestly never used this setup, so i'm not familiar with running anything but a big cab to the lows.... am i wrong about this?

EDIT: i just found the manual, i guess i can run 4ohm to the lows with a single cab. So here's my next question. should i run my 4 ohm 610 on bottom with my 8ohm 115 on top??

husky123 · #5 11-07-2011, 01:34 PM

Quote:

Originally Posted by gustobassman

EDIT: i just found the manual, i guess i can run 4ohm to the lows with a single cab. So here's my next question. should i run my 4 ohm 610 on bottom with my 8ohm 115 on top??

It's certainly worth a listen. Hook her up and see if you get the tone you like. One thing's for sure you will have a good bit more volume.

The 800 RB is one of the loudest 300 watts I've ever heard.

walterw · #6 11-07-2011, 01:41 PM

I think you're short-changing yourself. Run both 15s full-range into the 300w side and you'll have way more bass power. That one speaker is rated for lower wattage than the other means nothing at all, since (assuming they're both 8ohm) they'll be getting 150 watts each.

By biamping, you're taking the low end out of the one speaker, losing all the benefits of multiple cabs pushing low end, you're wasting a big speaker by only running highs through it, and you're reducing the power driving that low end, only getting 200 at 8 instead of 300 at 4.

The way to use the biamping is if you had another cab, a little one like a single 10 or something; you'd run both 15s on the low side and the little cab on the high side.

gustobassman · #7 11-07-2011, 02:01 PM

Quote:

Originally Posted by husky123

The 800 RB is one of the loudest 300 watts I've ever heard.

Agreed. I have never had any issue shaking dancefloors with my 610.

Walter - i think i will try that. they are both 8 ohm cabs, i just assumed the speaker power handling dif would make an impact on what the cabs could/would handle. I can definitely see how using a 10" for instance would be good for the highs. The D115XLT does have a tweeter (not a big fan of them though), that could bring out some sheen i'd imagine as opposed to trying to bang the highs out of the other 15. Time to try it out!

will33 · #8 11-07-2011, 02:09 PM

You're worrying way too much about the power handling thing. It's not that big a deal. You'll hear the speakers start to complain if you send it too much.

There's really no sense in biamping with a 15 on both sides. You don't have dedicated low and mid/drivers there. It may still sound cleaner if you do though as they are different drivers and with splitting the signal, they wouldn't be interfering with each other trying to play the same frequencies.

Keep in mind the high amp is 8ohm minimum.....and enjoy.

cchorney · #9 11-07-2011, 02:12 PM

sounds like a great rig. I have for many years run my gk800rb thru my 4ohm Kustom 2x15, and it sounds great like that. So you should try running both 8 ohm 15's thru the 4 ohn side, and maybe leave yourself some room for another cab on the 8 ohm side if you want to get excessive.

btw, the gk800rb has a reputation for sounding louder than it's rating. I know its never been "not loud enough" for me with my cab.

gustobassman · #10 11-07-2011, 02:22 PM

Quote:

Originally Posted by will33

There's really no sense in biamping with a 15 on both sides. You don't have dedicated low and mid/drivers there. It may still sound cleaner if you do though as they are different drivers and with splitting the signal, they wouldn't be interfering with each other trying to play the same frequencies.

Point taken.. i figured i'd try it out since i've never used the feature. I've had this head for almost 10 years, it's only mates have been a 610 and an 810. Either way i got a heckuva deal on some solid Eden cabs that sound great through my head. I'll have to tinker with some stuff later and see what happens.

Like i posted earlier, with the crossover at about 11:00 i get a pretty sweet sound. nice and full (to my ears at least, mind you i'm at home and not in the studio) but robust as well. I'm going to try the cabs on the low amp and see if i can determine a real difference.

husky123 · #11 11-07-2011, 04:31 PM

I disagree with not biamping it thru (2) 15's. I know it's not optimal but if it gets you the tone you're after then that's all that matters. It does for me and my ears. As always YMMV.

walterw · #12 11-07-2011, 08:46 PM

so you run one 15 with no low end in it? why?

without having to carry the low end, it might as well be a 10, or even an 8. (those would likely sound better, actually.)

**B-string** · #13 11-07-2011, 09:21 PM

Little known fact guys, the 800RB actually sounds deeper and fuller running in Bi-amp mode. If you own a 800RB and have never tried it, you need to. You'll find I am correct

walterw · #14 11-07-2011, 09:24 PM

with the right combo of cabs, you mean.

(i.e., a big one for the sub and a little one for the highs)

**B-string** · #15 11-07-2011, 09:30 PM

Quote:

Originally Posted by walterw

with the right combo of cabs, you mean.

(i.e., a big one for the sub and a little one for the highs)

It makes better sense, but even with matching 15" cabs the 300 watt "low" amp opens up in Bi-amp mode.

gustobassman · #16 11-07-2011, 09:43 PM

So far its a toss up. Sounds good both ways, maybe a little more "open" (?) sounding with the biamp mode? They sound fantastic. I have been using ampeg cabs for so many years this is just awesome.... I haven't even bothered with the Sansamp yet..

Then again, i am home and not in the studio. I can crank it somewhat, but not having the band here i'm not sure about how well it will cut through. I have gigged with a 2x15 cab before, this is just different. pretty darn cool!

walterw · #17 11-07-2011, 10:02 PM

now are you guys running both cabs into the low side and hitting the biamp button, or putting one cab on the "high" amp?

again, if you want actual bass headroom, you want both 15s on the low side, whether "biamped" or not. otherwise, you only have one 15 handling the lows, and that's just not very much.

you'll have no more low end than one 15 by itself, in which case, dragging out two to the gig is kinda silly.

**B-string** · #18 11-07-2011, 10:14 PM

Quote:

Originally Posted by walterw

now are you guys running both cabs into the low side and hitting the biamp button, or putting one cab on the "high" amp?

again, if you want actual bass headroom, you want both 15s on the low side, whether "biamped" or not. otherwise, you only have one 15 handling the lows, and that's just not very much.

Alright I'll spell it out for you. I used to run a 215 Acoustic Control cab loaded with Altec 421A's and a Fender Single Showman cab also load with a 421A. The 215 on the low amp and the single 15 on the high amp. The amp sounded deeper and really opened up in Bi-amp mode over just running both amps in full range. I believe the bandwidth of the LF353 (the first stage of the power amp) is better utilized in Bi-amp mode. I'm am not talking max headroom, I am talking sound quality of the sound produced. My 215 was a 8 ohm cab (421-16H X2) and honestly with the one 215 8 ohm from the 300 watt low amp headroom was never a problem. The adding of the 115 was for fun (and in Bi-amp better sound).

**B-string** · #19 11-07-2011, 10:17 PM

Quote:

Originally Posted by walterw

now are you guys running both cabs into the low side and hitting the biamp button, or putting one cab on the "high" amp?

again, if you want actual bass headroom, you want both 15s on the low side, whether "biamped" or not. otherwise, you only have one 15 handling the lows, and that's just not very much.

you'll have no more low end than one 15 by itself, in which case, dragging out two to the gig is kinda silly.

As for the part in bold, you would have to hear it before making a blanket assumption.

walterw · #20 11-07-2011, 10:36 PM

Quote:

Originally Posted by B-string

I'm am not talking max headroom, I am talking sound quality of the sound produced.

i can argue physics, power, and headroom (that biamping with just one 15 on the bottom means no more low end power than bringing a 15 cab by itself is just simple fact), but i can't argue "sound quality". that's entirely subjective.