800RB how flat is the response set flat?

[DavidEdenAria]

Referring to the VF controls off and the tone knobs at noon is the 800RB considered relatively flat or not?

I ask because it's been on the market a long time and I assumed players have an idea how flat or sort of baked in tone GK engineered into this bass amp.

I'm not in a position to audition other amplifiers to compare.

Thru my EV15L it seems to have a lot of extended top end for example but that speaker is known to have extended top end I think...Thanks in advance

 

[Passinwind]

There’s an RTA graph showing knobs at noon response in full range mode near the end of this web oage: How to use Gallien-Krueger 800RB Bi-Amp mode

So yeah, nowhere near dead flat, and the top end boost you are perceiving is definitely at least partly coming from the amp.

 

[Wasnex]

There’s an RTA graph showing knobs at noon response in full range mode near the end of this web oage: How to use Gallien-Krueger 800RB Bi-Amp mode

So yeah, nowhere near dead flat, and the top end boost you are perceiving is definitely at least partly coming from the amp.

? Either I am missing something or that article gives quite a bit of misguided advice, some of which could cause damage to an RBH cab.

The RBH cabs are not really suitable for biamping with the 800RB. AFAIK the tweeter HPF in RBH cabs is set at 5kHz. The crossover in the 800RB only goes to 1kHz. The article recommends a 500hz and 350hz crossover. This is a good recipe for a blown tweeter with a real 800RB and RBH series cab as the 5kHz HPF is bypassed when the cab is put in biamp mode. Not a hazard with a plugin, but you wind up with a severe mid-scoop as shown in the article.

The 800RB is really intended for use with a woofer and mid/high style cab. I biamped one into a Bag End S15D and a Ramsa WS-A200 12+horn PA cab.

 

[thegrimmbass]

I can't tell for the 800rb, but i recently compared the DI signals in pre and post on my 700rbii and there is just a slight low end boost in post eq. Nothing drastic in the high end. It's a similar amp, but at least two amp-generations after the 800rb. So i don't know if this is helping in any way...
I could post the audios if you are interested though

 

[Nebadon2000]

Let me start with experience I had
When working in Home Audio store a Rep came in with a new 'Auto EQ' that would make system flat

I choose a system in one of our sound rooms that sounded fantastic

He setup EQ with strategically placed Mic's turned it on and it did it's magic

Played system and it sounded Awful: When I told him that he said yes but it's Flat

I understand the theory of FRFR for Amps or Cab's but IME that may be more important in Cab's for some

@agedhorse has explained why better designers 'Voice' their amps based on players preference and perceptions and may have in a recent thread of yours

He also has mentioned knobs at 12 O'clock is just one position and can be adjusted

 

[Passinwind]

? Either I am missing something or that article gives quite a bit of misguided advice, some of which could cause damage to an RBH cab.

Thanks for the heads up. I didn't pay any attention to any of that, it's maybe not really relevant to the OP's question here (?) but if it's wrong that's certainly valuable info. I can't recall a single person I know (outside of TB) ever using the biamp feature on an 800RB, IMO the implementation's a bit limited.

 

[Phreaky Phriday]

I always thought Bi-amping is more for old cabs that have limited frequency ranges

 

[erratick]

Flat in what way? The 800RB is pretty strongly voiced. It's got a certain (mostly desired) sound. Flat doesn't mean frequency response is flat in this case, just that you have the full range of tonal options from the EQ and voicing filters. If you use Biamp or cross over that will affect things as well.

From the manual:

"Your amplifier is designed to sound about right with the tone controls set flat (at"5"). We therefore recommend you start with the EQ set flat, the voicing filters out, and the crossover at 500hz ("5")."

also:

"You may have to experiment with the crossover point and the relative levels of the high and low masters. It is best to adjust them before the EQ. They should be adjusted to give the most desirable sound without distorting the high end speakers. If the crossover confuses you, try switching out of the bi-amp mode and set up your sound in the full range mode first.

4. Once your basic levels are set, work with the voicing filters. "

You should probably go through that. Note- full range mode is not FRFR as people know it today- it's full range compared to having the crossover in play/biamping. The 800RB is voiced as a bass amp, and people desire that voice still.

I still have a 400RB and used to play through an 800 pretty regularly back in the day.

 

[Wasnex]

Thanks for the heads up. I didn't pay any attention to any of that, it's maybe not really relevant to the OP's question here (?) but if it's wrong that's certainly valuable info. I can't recall a single person I know (outside of TB) ever using the biamp feature on an 800RB, IMO the implementation's a bit limited.

Some of the info could be useful.

Here is the full range curve. AFAIK this is with controls at 12:00.

I think this is useful for the OP.

This is the biamp response. AFAIK with controls at 12:00.

IMHO this curve probably doesn't really reflect a huge change in the amp voicing in biamp mode. My guess is the gain structure of the low and high signal paths is a bit different. IMHO the nominal level of the lows appears to be around +5dB and the nominal level of the highs appears to be around -1.5dB. With level matching, this curve would probably look a lot more like the full-range curve.

The low side has a 300W amp and the high sides has a 100W. The decibel difference between 100W and 300W is ~4.8dB. More power is typically required for the lows. For flat response in biamp mode, the first thing one would do is acoustic level matching between the low range and high range cabs. amp.

 

[Passinwind]

Some of the info could be useful.

Here is the full range curve. AFAIK this is with controls at 12:00.
View attachment 7439729
I think this is useful for the OP.

This is the biamp response. AFAIK with controls at 12:00.
View attachment 7439731
IMHO this curve probably doesn't really reflect a huge change in the amp voicing in biamp mode. My guess is the gain structure of the low and high signal paths is a bit different. IMHO the nominal level of the lows appears to be around +5dB and the nominal level of the highs appears to be around -1.5dB. With level matching, this curve would probably look a lot more like the full-range curve.

The low side has a 300W amp and the high sides has a 100W. The decibel difference between 100W and 300W is ~4.8dB. More power is typically required for the lows. For flat response in biamp mode, the first thing one would do is acoustic level matching between the low range and high range cabs. amp.

Yep, that first curve was what I specifically pointed to in my first post and I definitely think it has value to the OP and any scientific minded readers, assuming it's accurate. And understanding level matching or other level settings is a must to make any sense of crossover implementation, passive or active, IMO and IME.

To me, making the high side only 8 ohm capable was a huge mistake, but OTOH the amp certainly sold pretty well and is still fairly popular for backline around where I live.

 

[Phreaky Phriday]

High side 8 ohm is great for playing at home, no need for extra power

 

[winston]

FWIW the linked article is based on the Audiffex 800RB plugin, not the actual amp - which explains why they are running the top amp into an RBX tweeter...it lets you combine amps/speaker cabs that wouldn't actually work IRL:
"In this article, we show how to use this feature with the GK 800RB amp simulator from the GK Amplification 2 Pro plugin".

I have used that plugin, the BrainWorx/PluginAliance 800RB, and the circuit-modeled 400RB Bass Invader in Native Instruments' Guitar Rig 7.
Having owned/used a bunch of GK stuff from the 80s/90s I find the one in Guitar Rig 7 to be the most accurate feel/sound-wise, then the BrainWorx (though the low/high amps/IRs appear to be 180 degrees out of phase last I tried), with the Audiffex in last place...
So I am not 100% the Audiffex modeling is accurate, and would take any specs from that plugin with a grain of salt.

IIRC, @fdeck once analyzed the response of a GK Backline head with similar EQ/filters to the RB series.

? Either I am missing something or that article gives quite a bit of misguided advice, some of which could cause damage to an RBH cab.

The RBH cabs are not really suitable for biamping with the 800RB. AFAIK the tweeter HPF in RBH cabs is set at 5kHz. The crossover in the 800RB only goes to 1kHz. The article recommends a 500hz and 350hz crossover. This is a good recipe for a blown tweeter with a real 800RB and RBH series cab as the 5kHz HPF is bypassed when the cab is put in biamp mode. Not a hazard with a plugin, but you wind up with a severe mid-scoop as shown in the article.

The 800RB is really intended for use with a woofer and mid/high style cab. I biamped one into a Bag End S15D and a Ramsa WS-A200 12+horn PA cab.

 

[Wasnex]

FWIW the linked article is based on the Audiffex 800RB plugin, not the actual amp

Thanks. FYI I understood the article was about a plugin rather than the actual amp and cabs. Just concerned that someone could draw the conclusion they can safely biamp an 800RB into an RBH series cab. Let me be very clear: Don't try this with a real 800RB and GK RBH or NEO series cabs. You will almost certainly blow the tweeter.

I don't really understand the point of modeling the 800RBs biamp function with a cab that is not compatible with it. I guess it demonstrates the power of the plugins modeling, but IMHO the resulting response curves appear to be awful, as one might expect. I think it would be a much better demonstration of the plugin's usefulness to actually show results with compatible cabs.

 

[fdeck]

IIRC, @fdeck once analyzed the response of a GK Backline head with similar EQ/filters to the RB series.

Indeed, and the further back it recedes in my memory, the less accurately I remember it. Something like 10:00, 2:00, 2:00, 10:00. Nothing drastic. And even two different builds (with other noticeable design differences) of MB200 heads have slightly different "flat" settings

 

[rapidfirerob]

Thanks for the heads up. I didn't pay any attention to any of that, it's maybe not really relevant to the OP's question here (?) but if it's wrong that's certainly valuable info. I can't recall a single person I know (outside of TB) ever using the biamp feature on an 800RB, IMO the implementation's a bit limited.

I used the biamp feature on the 800RB in the 80s. It was a thing back then.

 

[Passinwind]

I used the biamp feature on the 800RB in the 80s. It was a thing back then.

I had a variety of biamp and triamp rigs back in the day, and owned an early GMT amp for a while, just never saw anyone doing that with an 800RB for whatever reason.

 

[winston]

Thanks. FYI I understood the article was about a plugin rather than the actual amp and cabs. Just concerned that someone could draw the conclusion they can safely biamp an 800RB into an RBH series cab. Let me be very clear: Don't try this with a real 800RB and GK RBH or NEO series cabs. You will almost certainly blow the tweeter.

I don't really understand the point of modeling the 800RBs biamp function with a cab that is not compatible with it. I guess it demonstrates the power of the plugins modeling, but IMHO the resulting response curves appear to be awful, as one might expect. I think it would be a much better demonstration of the plugin's usefulness to actually show results with compatible cabs.

Yeah, one of the things I like about the Native Instruments Guitar Rig 7 model is that it goes for the 400RB and doesn't bother with the biamp setup.

 

[micguy]

Indeed, and the further back it recedes in my memory, the less accurately I remember it. Something like 10:00, 2:00, 2:00, 10:00. Nothing drastic. And even two different builds (with other noticeable design differences) of MB200 heads have slightly different "flat" settings

10/2/2/10 is the knob clock positions for the flattest you can get a Rumble V3 amp (it's not completely flat, but close). Not sure if that's coincidence, or if you' remembering something different than you think you are.

 

[Nuisance]

Not sure if accurate, but I found this information in an article (probably here on TB) a few years back.

Flat settings for the GK:

• High at 11:00
• High-mid at 2:00
• Low-mid at 1:00
• Low at 10:00