Going For Broke

[Buzzerelli]

I am an old ( repeatold) bass player who is getting back into playing. When I was young I had a dual showman amp with 2 2x15 cabinets. It rocked but wasn't big enough for some of the venues I played. I wasn't rich so I had to make do. I recently dusted off my old guitars and decided now that I had some money and some skills to create the perfect bass wall. I purchased a sunn beta bass amp, a sunn concert bass amp and several speaker bottoms. I made 4 PA speakers and am making a few 2x3 foot sunn clones for effect. Using 8 ohm 15 inch speakers- eminence. I also bought a couple of 18 inch to make some gig combos.

The problem is- I am an electronics dummy. I know that it is possible to burn out an amp by under ohming the output but I am not sure how to avoid this and still have the ability to fill a gymnasium with sound.


Any advice you may have would be greatly appreciated. ( I do know how to read a digital electric meter)

I was kind of hoping to make a distribution box to plug the speakers into.


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[trevorus]

Buy some power amplifiers and chain them off of a single preamp. It ought to work quite nicely!

[black_labb]

well the basic rule for adding speakers is you double the impedance when you double the number of speakers in series, and you halve the impedance for paralell. this is assuming the speakers are of the same impedance.

so if you had 2 8 ohm speakers, you could wire them in series to get 16 ohms, or paralell to get 4. as you add speakers you get more options, as you could have 2 eight ohm speakers ins series, which is in paralell with another 2 in series to get (8x2)+(8x2) all divided by 2, giving you 8.

as for power handling, you divide the power output by the number of speakers that are there to give you the power going through each speaker. that is assuming the speakers are wired to get the same power, which is adressed below.

having different impedances can work, but you have to be careful, as it can be easy to give some speakers twice the power compared to the others.

for example, having 2 8 ohm and 1 16 ohm can be good for a cab where the 8 ohm speakers should only get half the output of the 16. you can put the 2 8 ohms in series, giving you 16, and then paralell that with the 16 ohm speaker. this gives the 16ohm speaker more output than the individual 8's. would make a good 1x15,2x10 cab or similar.


the one question i have, why do you need so many cabs? are you planning on playing an outdoors festival without a pa? do you have an underpowered amp and get the volume with extra cabs? im not sure how long ago you left bass playing, but there are plenty of amps around with 500 and 600w output for quite cheap, and 1200w amps arent uncommon. many people these days play a 1x12" speaker that can handle alot of power with a 500w or so amp to power it and get enough volume without enough cabs to fill 3 vans. id love to have a wall of speakers for bass, but in reality its impractical and unnessesary, especially with the high power rated speakers with high sensitivity.

[tubeswell]

Those little 1 x 15" ported cabs are good. I had one about 25 years ago with a JBL E130 (and then a K130 "Black Widow"), powered by a locally made 300W MOSFET bass amp head. It was really punchy and I didn't need anything else. (I never played it a full volume either, but it was gutsy enough to cut through the mix). Plus it was about all I could manage to lug around.

FWIW, if you don't provide enough power to drive all those bins, then you won't get the performance out of the speakers. They won't sing properly unless they are properly pushed - which will be numbing. But don't let me tell you how to suck eggs... ;-)

[Brad1]

Buy some power amplifiers and chain them off of a single preamp. It ought to work quite nicely!

Not necessarily. Since there are a variety of speakers in that wall of doom, what might sound good running to one set may not sound good through another. Because of the (probably) different frequency responses, sensitivity, impedance and power-handling capabilities of each type of driver, what makes, say, the Eminence good and punchy may make the others fart out. And, if you then get the others good, the Eminence then won't be doing their best.

Each set of different type of speaker should get their own preamp settings, and as mentioned already, power amp that most closely matches it's requirements. Otherwise, you'll likely end up with a wall of non-defined, low-end mush. You could use different preamps, like find something like Ampeg SVPro bass preamps, or it might even be able to be accomplished with one preamp run through several active crossovers feeding different amps for each set of like speakers.

I don't think bass is like guitar where sometimes it's desireable to run dissimilar speakers to get different characteristics from each. Bass needs to be clean and defined.

I agree with the position that no bassist on Earth needs that kind of bass rig. HOW THE FREAK LOUD DO YOU NEED TO BE??!! And, how's the rest of the band gonna hear themselves? Bigger and more amps? Until you all need earplugs to lower the stage volume? Why?

Brad1

[Buzzerelli]

Maybe I am out of touch. In my day you had to have at least a dual showman to play. So, I figured, what is too much? I like that "wall of doom" he he I guess it is. At least it might be good for putting out matches on low "E". Got more than enoug h to gig around here. I used to play at the Grande Ballroom and Club Pony Tail in my hayday.
Buzz
"the overachiever"

[black_labb]

wether you are overdoing it or not, its good to see that you are working on some nice cabs.

usually someone would have their cabs running all in paralell. usually you would have 2 jacks connected to the same wires within the cabs, and a speaker cable to the second cab would put them in paralell. this would halve the impedance assuming they are equal. the problems is amps have certain impedances they want, and you can halve them too many times and get a value that isnt stable on it (for a solidstate amp) or is a value for which there is no impedance tap on the valve amp.

you will probably have to make a box that puts speakers in series. if the speakers you got are 16ohms, then you could put 8 in paralell (or 4 in paralell on a 4 ohm impedance) on an amp that is happy to run at 2 ohms (some solidstate amps, dont think there are many tube that do though. but then again a tube amp that could power so many big speakers properly would be horribly big)

[Steve Conner]

Well, you can have any size of bass rig you want! Assuming you have your own van to carry it in, and you can get gigs in big enough venues that it will all fit on the stage.

I play bass too, and I've never got a gig that couldn't have been covered by just one of those 1x15" ported cabinets.

PA systems have improved a lot since the 70s. They now have huge amps and massive woofers (I've played at gigs where they had four 2x18" bass bins with a couple of kilowatts of amps) and the sound guy takes a D.I. feed from the bass, so the bass rig is really just a monitor for the stage. It doesn't have to shake the whole room any more.

Also, my band is a fairly quiet, some might even say wussy pop band. I'm using a 60w tube amp into a 2x10" just now, and I don't even have to crank that. I had a 2x15" before, but I sold it because it was a hassle to transport, and way more efficient than needed, so the amp was barely ticking over and sound guys were still glaring at me to turn down. I'm thinking about making an even smaller cabinet now, so I can have a bass rig that fits in a taxi, for easy transport home after half a dozen beers.

Regardless, if you want to get that huge wall of woofers all working at once, I'd start by buying two stereo power amps used. The solid-state kind they use for PAs, preferably 2 ohm rated. Hook the speakers up in four parallel groups, connect those to the four outputs of your amps, and then drive all the amps off some kind of tube preamp. And don't eat heavily for a few hours beforehand, in case you hit a brown note

If you want to use your Sunns, you should probably load each one with paralleled speakers down to its minimum impedance (should say on the back of the amp what that is) and then hook the remaining speakers to a power amp as above. Hopefully the Sunns will have slave outs that you can drive the power amp with.

[Brad1]

Well, if one insists on using them all, and paralleling them all runs you out of amp outputs, you COULD try to do some rewiring?

Maybe series connect some of the x2 speakers in their cabs? Just as an example: If they have 4 ohm cabs with two 8 ohm speakers, if you series them, you'll have a 16 ohm cab, that you could then parallel to another like 16ohm cab for 8 ohms. Parallel that to a pair of 8 ohm cabs for 4 ohms.

You may try to do some math with the configurations you have to see what the possibilities might be. I wouldn't go TOO far with all that, though, but you may be able to squeeze another couple cabs in if you run out of amp, otherwise.

I still suspect that driving all those differing speakers from one preamp with one set of tone controls will get you sound, but may not let ANY of the speakers reach their own potential when you may have to sacrifice the full capabilities of any one to run any other in it's sweet spot. If you do manage to get them all to not fart, woof, be too bright, etc., you may end up with a rather constricted range in order to satisfy all of them.

"That one's farting...back off on this.....now this one is too bright...back off on this....that one's still too wooly, back off on this. OK, now none of them are doing anything particularly nasty....but why does it sound good only on my G string, now?"

But, can't hurt to try, I guess.

Brad1

[Bruce / Mission Amps]

Maybe I am out of touch. In my day you had to have at least a dual showman to play. So, I figured, what is too much? I like that "wall of doom" he he I guess it is. At least it might be good for putting out matches on low "E". Got more than enoug h to gig around here. I used to play at the Grande Ballroom and Club Pony Tail in my hayday.
Buzz
"the overachiever"

Unless there are more then just a few other Motor City ex-wankers here... I doubt too many players will know what the Grande Ballroom is! I spent more then a few night there and in kicker bands too... I think my teeth still hurt from the last time we opened for the MC5... sheesh.

[Buzzerelli]

Unless there are more then just a few other Motor City ex-wankers here... I doubt too many players will know what the Grande Ballroom is! I spent more then a few night there and in kicker bands too... I think my teeth still hurt from the last time we opened for the MC5... sheesh.

I played there after Bob Seger and The Crazy World Of Arthur Brown. Played all over Michigan, Ohio, Illinois in my younger years. Even shared the stage with Ted Nugent and the Amboy Dukes, was the back up band for the Animals and the Beach Boys when they hit Michigan thanks to Robin Seymor from CKLW- he liked us.

[Bruce / Mission Amps]

I played there after Bob Seger and The Crazy World Of Arthur Brown. Played all over Michigan, Ohio, Illinois in my younger years. Even shared the stage with Ted Nugent and the Amboy Dukes, was the back up band for the Animals and the Beach Boys when they hit Michigan thanks to Robin Seymor from CKLW- he liked us.

Yup those were the days... we use to cross the river to Windsor too, and do Seymor's Battle of the Band things along with the ones at the MI State Fair which at the time was sponsored by local music stores, Shure, CKLW and VOX amps!! Fun times.
By the way I went to see Arthur Brown every time he was around Detroit.. always brought down the house with FIRE... ha ha ... I wonder if that old fart is even still alive.

Detroit was different then. Use to run up to Ann Arbor and visit Nugent during his "back yard parties". Ya know, ... back in those days lots of big Detroit and national acts would come over to the small hot clubs or hotels and jam with locals bands.
I use to play drums for a guy named Gino Washington (who even had his own local TV talent show show.. those were actually fun to do)... and anyhow he was pretty good friends with the old Temptations and every once in a while Davis Eli Ruffin (David Ruffin) would come by with a couple of his singer buddies and we'd do a couple MOTOWN sets with him ... fun days.. too many big heads now and that time is long gone.

[Buzzerelli]

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