guidance for configuring a Yamaha PB-1

[the_hook]

I aquired a very nice PB-1 a few months ago, but never had a chance to hook up my entire rig with it until now.

Can someone guide me on how to use the parametric EQ and the crossover? I'm running a 2 channel power amp with channel A into a 4 ohm 2x10 Bag End cab, and channel B into an 8 ohm 1x18 BE cab. I'm using passive basses.

[bongomania]

Well, the simplest place to start (not the "perfect" or "only" answer though) would be to connect the high band output of the PB1 to the amp channel with the 210, and the low band output of the PB1 to the amp channel with the 118. Set your EQ flat. Set both high and low band crossover frequencies to about the same frequency; 200 Hz would be a decent starting point. Also set their level knobs to the same level for now.

Now play. From here you can hear whether the sound is imbalanced toward the highs or the lows. Use the gain knobs on the power amp to adjust until the highs and lows seem balanced and "right" in overall strength. At that point, if you want you can use the frequency and level knobs on the preamp to fine-tune the tonal response from each cab. Just experiment (but remember to write down the "good" settings so you can return to them).

As for the para EQ, are you familiar with how they work? If not, check out the article on EQ types in the FAQ in my sig. If you're already familiar, then did you have a more particular question about using it?

[AlexanderB]

+1
I do not know about the crossover settings on that preamp, but I would personally start with a lower crossover setting. 200Hz is often a bit too high for most 18"s and it will also not use all of the 10"s tonal range. I would start at around 100Hz, if available.

IMHO.

/Alexander

[Rick Auricchio]

Keep in mind that both cabs are designed to cover the full range of the instrument. So by bi-amping, you're wasting all the upper end of the 18. And wasting all the low end of the 10s.

The result is that you're lugging around cabs that aren't being used to their full potential. That's a step backward.

[johnk_10]

you might keep in mind that on the Yamaha PB-1, the 'flat' setting for the tone controls is treble=0, middle=10, bass=0 with the parametric in the center detent, and i just verified this with a real time analyzer.
the bass control operates at approx 100Hz (shelving)
the treble control at 4Khz (shelving)
the middle control's freq depends on where you have the bass and/or treble set, but its generally about 650hz when the bass and treble are set on 5.


i also just checked out how accurate the markings for the parametric are on mine, and:
the 50Hz setting is actually 40Hz
the 100Hz is 80 hz
the 250Hz is 180Hz
the 500 is is 500Hz
and the 2.5Khz is 2.4Khz.

[AlexanderB]

Rick said:

Keep in mind that both cabs are designed to cover the full range of the instrument. So by bi-amping, you're wasting all the upper end of the 18. And wasting all the low end of the 10s.

Well, it really does not work that way... The sensitivity, frequency response, maximum excursion and power handling are very important factors to include. (And I am not even entering all the alignment and phase discussions.)
Disclaimer - I am not too familiar with the Bag End cabs - they might be completely different from any other bass cab I have seen.)
From a sensitivity pont of view, two parallel 10" will probably be pretty close to that from one 18". (Equal gain setting for both channels if run full range.)
But from a power handling persepective, a proper 18" cab would probably take 5 or 10 times as much power at 40Hz compared to most 210s. In order to have the speakers to reach maximum excursion (output) at the same time, the 18" channel would need 6 to 10dB more gain than the 10" if run full range!
Also bear in mind the extra power handling and clarity from the 10"s when they are not asked to reproduce low bass.
The sound from the 18" will also be cleaner and "bigger" when used for only lows.

I know of NOBODY from the pro audio world that would run vastly different sized, fullrange speakers in a setup like that. Active crossing, lows to 18" and highs to 15", 12" or 10" top cabs.

If your purpose is NOT to maximize SPL and sound quality, please disregards my post...

[Jaco who?]

You can "maximize SPL" by turning down the one side of the power amp that goes to the most sensitive cab. The crossover isn't really necessary for that. It might be useful with maybe a 75-100 hz difference in certain cases (rooms) but it seems like more trouble than I'd care to deal with.

[AlexanderB]

Judging by your answer (especially the part: "It might be useful with maybe a 75-100 hz difference in certain cases "), I get the feeling you do not fully understand the function and purpose of using an active crossover and a bi-amped rig.
Sensitivity and power handling do not automatically go hand in hand.
Controlling frequency range for different speakers, avoiding overpowering outside passband and utilizing the amps output power in the most efficient way can not be compensated for by turning the gain knob in any direction.

That is what the crossover (be it active or passive) is for.

/Alexander

[Jaco who?]

I just think if your using two cabs both designed to operate full range, using a crossover is sort of a needless complexity. Maybe running the 1x18 with a dedicated midrange cab, but it doesn't sound like the 2x10 really fits that description. I know perfectly well how a crossover works, thank you.

[morebass!]

I've used my PB-1 with a JBL 18" sub and a Peavey 2x10, each cab powered by 450 watts. I tried a variety of crossover points and ended up around 200hz despite JBL's recommendation to not exceed 120hz for the sub. It sounded too thin in the low mids with the x-over at 100. I should say that I like the concept of bi-amping but it hasn't ever worked for me in practice. Back in the 80's I tried bi-amping my GK 800RB into an 18 and a 10 and also through a 2x15 and 10 but it never worked out. Seems like those all-important low mids are lost when bi-amping. However, one nice thing about the PB-1 is that you set the x-over points individually so you can overlap or even run one speaker full-range and x-over one. With your Bag Ends I'd run the crossover for the 2x10 very low or use it full range. That cab can handle low end well for a 2x10. Then set the crossover point on the 18 to taste depending on your lowmid vs. deep lows preference.

With bi-amping you'll have to tweak a lot but it might pay off in terms of efficiency and tonal range.

[AlexanderB]

I also somtimes run my rig bi-amped with active crossover.One setup is a 210 loaded with Deltalite II 2510 and one box with a Kappalite 3015LF. I have not yet used this very setup live, but cutting the lows from the 10" do improve headroom and clarity at rehersal. The 3015 LF can be run up to the highest cross over frequency available (360Hz) without problems with break up. Something many 18" can not do.
Going higher than 150 Hz in my rig means not fully utilizing the capacity of the tens, in the line of Jacowho?'s posts.

Given that you have control over and understanding of what you are doung, you can absolutely run overlapping frequencies. That includes running the 210 fullrange and adding lows through the 18".
As long as you stay in such low frequencies there might be added impact in the bass range without cancellation issues. (Those are more prevalent in the mids as the wave lengths are shorter and intereference patterns occur easier.)

/Alexander

[Derek DiFilippo]

Originally Posted by johnk_10

you might keep in mind that on the Yamaha PB-1, the 'flat' setting for the tone controls is treble=0, middle=10, bass=0 with the parametric in the center detent

In my experience with the PB-1 it could sound great as long as you were aware of the flat settings, described as above. Inadvertently dialing down the midrange on the PB-1 can really suck the life out of it.