• TalkBass has been independent since 1998. Add your voice.
    Create a free account to reply to discussions, view embedded media, and browse with fewer display ads.
    Join freeLog in
    Want zero display ads or expanded classifieds tools? Compare plans.

Two Identical Amps-Two Identical Cabs Rig

I'll keep it as simple as possible. Already had a few things in mind to try but thought I would ask in case I overlooked anything.

And I'm sure there will be times when I will not have both amps on. It won't be at 2 amps always on scenario.

More speakers always sounds better. If the cabs are stacked, even with one amp, you monitor better because the sound is closer to your ear. When monitoring is better, you play better. I often raise my 115 cab on an ATA case, sometimes a Leslie cab.
 
For many venues, (depending on the genre, and the volume of the rest of the band), 100 Watts is more than adequate, if you have efficient, and properly positioned speaker cabinets.

For just plain more volume, you get more bang for your buck by increasing speaker displacement, (diameter, and cone movement), by adding identical speaker cabinets.

But, you are intending to make use of two distinct signal chains as a way to obtain a certain sound, and not to achieve greater SPL.

My personal opinion is that it is unnecessary expense and hassle for little reward.

At least you will be using identical speaker cabinets, (I hope).


Ok, say I use one 50T with two 8ohm 212 cabs. Will it sound as loud as running 100 Watts through only two 112 cabs ?
 
The amount of acoustical energy, (volume) an amplifier and speaker system puts out is dependent (in part), on the power available from the amplifier, the cubic volume of air the amplifier and speaker system movement can displace, and the efficiency of the speaker system. The acoustic power decreases as the distance from the speaker increases. The environment, (inside a room, or outdoors with few reflective boundaries) also has an effect.

I think 2 212 cabinets at 50 Watts, might be as loud, if not louder than 2 similar 112 cabinets at 100 Watts. It would be interesting to try it as an experiment.

Maybe someone with sound system engineering training and experience can give you a better answer than my uneducated guess.
 
Last edited:
  • Like
Reactions: lowplaces
Ok, I'm pretty patient so I'm going to let it simmer for one more week.

Good arguments presented for not running two heads and great suggestions for doing so.

I considered the option of two Avatar 212 cabs instead of adding a second PF-50T. But that would add up to around 80 pounds to my rig depending on if I went with the Neo speakers or the LF ones. Also, two of those Avatar 212's what cost more than a second PF-50T.

I searched and it seems the Avatar 212 cabs got an awful lot of love around here a few years ago. Don't see much mention of them recently. Have they fallen out of favor for some reason ?

So I got a lot of thinking to do. If I go with one amp, I can still switch from dead clean to overdrive with an ABY. But that it eliminates my ability to run one amp clean and one amp over driven. That is one option that really drives my want for a second PF-50T. It also eliminates the @NoiseNinja appealing suggestion for my signal chain.

As far as stereo effects with two heads, I totally understand how great it would be at home for fun but I also relent to the fact that most FOH are going to be mono anyway, as @Jazz Ad pointed out. But then again, in a small venue where only the vocals would be coming out of the PA, I think stereo effects could in fact sound great depending on placement of the speakers.

Regarding the issues a good sound man would have to deal with running two heads into two cabs, I understand and accept that as well. But as @ole Jason pointed out, there are two venues right here in town where the sound guy could make it happen.

So that's it. Sacrifice versatility options a second head offers for the reasons given for FOH issues, or get the second head and just be flexible depending on the venue.

Ironically, I just realized that last paragraph above may well have settled the matter.

We'll see.
 
As far as stereo effects with two heads, I totally understand how great it would be at home for fun but I also relent to the fact that most FOH are going to be mono anyway, as @Jazz Ad pointed out. But then again, in a small venue where only the vocals would be coming out of the PA, I think stereo effects could in fact sound great depending on placement of the speakers.

You also need to consider that even if you get the placement right so you don't cause cancellations, you will still lose 3db due to the speakers not coupling.
 
  • Like
Reactions: lowplaces
I don't think stereo has much value for a bass in a live setting. The psycho-accoustics of low frequencies don't lead to a perceived source point or points. You're not going to get much effect, for the hassle involved. The best argument I can think of for two amps is to run each pickup into it's own amp to EQ seprately - in effect, bi-amping the bass. I'm not saying to do that, or not. It's the best reason I can come up with to have 2 amps on one bass.
 
  • Like
Reactions: lowplaces
I think that you might be the only person to notice if you run a stereo rig at a show.
I'm not going to argue that at all. I have no experience running two amps.

But what about the situation in a small bar where only the vocals are running through the PA ? Sensible volume levels, both stage volume and PA volume where the bartender wouldn't have to strain to hear what the patron at the bar is ordering.

If I have my speakers separated in that scenario, unless I am standing Center Stage or right between the two speakers, wouldn't the audience actually hear, say a stereo chorus, even better than I would ?
 
Doubling wattage = +3db

Doubling speaker surface area (together, not separated) = +3db

If you were to stack your cabs and use both heads you would see approx. +6db

If you stack your cabs, and only use one head - +3db

Only one head, and separate your speakers - no gain.

One last question.

You offered "If you were to stack your cabs and use both heads you would see approx. +6db"

That would be approx. +6db whether or not the cabs were 112 or 212 ? Or would doubling the speaker surface area also add 3db for a total of 9db ? Talking identical cabs with two heads as you described.
 
Last edited:
In the early days, guitar amps flirted with stereo. Speakers were side-by-side in the same cabinet. This Magnatone is one example (Invalid Link Removed) of an amp that had a very effective stereo vibrato sound. To this day, Magnatones are coveted for their true vibrato circuit. Not that there aren't effective pedals available today that can produce a good sound.

But to get an even better effect, W-I-D-E -- S-T-E-R-E-O, with speaker cabs separated produces a good sound.

You really have to experiment to see what any setup will do. There are limits as to what navel gazing can accomplish. :laugh:
 
  • Like
Reactions: lowplaces
I have PMd TB member Duke Lejuene, and asked him to advise us regarding the questions raised in this thread.

One of the great things about TB is that there are some very smart, and educated members who are willing to educate us who are not.

Let's see if he can enlighten us with some of his vast knowledge of speakers systems.
 
  • Like
Reactions: lowplaces
In the early days, guitar amps flirted with stereo. Speakers were side-by-side in the same cabinet. This Magnatone is one example (Invalid Link Removed) of an amp that had a very effective stereo vibrato sound. To this day, Magnatones are coveted for their true vibrato circuit. Not that there aren't effective pedals available today that can produce a good sound.

But to get an even better effect, W-I-D-E -- S-T-E-R-E-O, with speaker cabs separated produces a good sound.

You really have to experiment to see what any setup will do. There are limits as to what navel gazing can accomplish. :laugh:

Navel gazing ? Lol, there's a song in there somewhere !

Regarding that vibrato on the Magnatones. Have you ever heard the term wide swing tremolo ?

One of my favorite bands has an album titled Wide Swing Tremolo.

When I Google it all the comes up is that album. I just wonder where Jay Farrar of Son Volt got that term. Perhaps it was just a descriptive term of certain vibrato/tremolo circuits back in the day.
 
  • Like
Reactions: beans-on-toast