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Mixing Boxes no Xover Rant

S

spode master

Jan 21, 2007
738
3
#1
Why does the commercial bass rig world encourage sillyness like,4 X 10 running in parallel with a single 15 cab, with no Xover.

Why why why?

I guess commercial product developed for "Musical Instruments" are exempt from sound speaker design practices.

Sorry just bored and stirring up some s!@#.

I know its all about subjective taste at the end of the day.

Antone-
 
#2
Because most bassists don't know from the "correct" way to do audio, and manufacturers are only interested in sales. They see someone like Flea using 410's and 115's and they think it's the way to go. Hell, I'm 47 and I didn't even know it until recently. But the more I try to apply the "rules" to my rig, the happier I am with my sound, so I'm convinced totally, and any subsequent rigs I assemble will all take into consideration the lessons I've learned over the last year. Except, of course, for when I get my SVT head done. I've got an old straightback 810, and I will make an exception for that cab ;)
 
#3
A lot of this is predicated on getting enough useful excursion - xmax - to not be living in fart city or blowing drivers when things get cranked. Double or quadruple your drivers and you thus double or quadruple how much wattage can be applied before that happens ("RMS" figures really don't mean much to bassists, but mechanical/excursion figures do).

Also, the availability of drivers that actually can handle a lot of excursion singly makes it easy to stay with the 4-by ethos - especially when one considers that a dedicated midrange driver (hard to come by a small midrange driver that is sensitive and handles power gracefully also) and lossy passive crossover typically needs to be used with longer-excursion woofers in order to fill in the crucial midrange. But solving THAT problem leads to enclosures/systems that have a decided wideband performance edge with better horisontal dispersion.

BTW, spode master, you'd end up with a better rig if you aligned your midrange drivers vertically ; }
 
#4
greenboy said:
BTW, spode master, you'd end up with a better rig if you aligned your midrange drivers vertically ; }
Click to expand...

I know I can still stack it vertically the pattern will narrow vertically in the 1khz range instead of horizontally. However if I put the tweeter up top of a vertical column. Polar at xover will be even worse, so 6 of 1 half a dozen of the other. The tweeter is probably in about as good of a place as it can be.

Heres the basic rule of thumb you gain 3dB sensitivity every doubling of drivers and you get 3dB more power handling (as long as the drivers are no more than 1/4 wave on center around its upper range. You will get that gain in sensitivity.

The more you double, the more your polar pattern will change. You can play little phase and delay tricks with the arrays to minimize pattern narrowing and lobing but that gets complicated.

Play with EVI array show if you can find it and you'll see what I mean.

Antone-
 
#5
spode master said:
Why does the commercial bass rig world encourage sillyness like,4 X 10 running in parallel with a single 15 cab, with no Xover.
-
Click to expand...
For the same reason why for 30 years major PA cab mfrs built trapezoid cabs, encouraging their use in cluster arrays despite knowing it was the worst possible way to array cabs: They sold. You might was well ask why Detroit embraced the Uber pickup truck and SUV- until three months ago. :rollno:
 
#6
Oh yah,

I don't advocate external Passive xover networks.

May as well Bi Amp the rig. But make sure your bottom has as much or more SPL headroom.

And my 4 X 12 sealed sub will never xceed xmax with 2kW down to 1Hz.

The 2 X 8" drivers should have enough XMAX to handle 400Watts and just hit xmax around the mid 40's. I plan on crossing over higher. For Bi amp

But this thread isn't about my rig! Its about THEIRS!

Well Put Bill!!

But I thought Hubbards peak was a myth!

Antone-
 
#7
I'll mix & match anything! I have tried a whole bunch of rigs. TE/Crown, Eden, Ampeg, GK, Mesa heads. 8-10, 410,1-18,2-15,210,1-15, all different combos of the above, and They all sound pretty good to great (within a volume window). It's when you get into higher volumes that narrows the playing field. There is so many variables. Stage, PA, rooms, voltage, MOODS!

I'll piss on a spark plug if it will make it work!

I don't think the amps make that much diff any more, unless they are total crap.

Someone here said, "It's not the arrow, It's the Indian!"


So, when I get all crazy and think I need a different setup, I just bash myself in the head with a shillelagh and tell myself to STOP IT!





.
 
#8
greenboy said:
A lot of this is predicated on getting enough useful excursion - xmax - to not be living in fart city or blowing drivers when things get cranked. Double or quadruple your drivers and you thus double or quadruple how much wattage can be applied before that happens ("RMS" figures really don't mean much to bassists, but mechanical/excursion figures do).

Also, the availability of drivers that actually can handle a lot of excursion singly makes it easy to stay with the 4-by ethos - especially when one considers that a dedicated midrange driver (hard to come by a small midrange driver that is sensitive and handles power gracefully also) and lossy passive crossover typically needs to be used with longer-excursion woofers in order to fill in the crucial midrange. But solving THAT problem leads to enclosures/systems that have a decided wideband performance edge with better horisontal dispersion.

BTW, spode master, you'd end up with a better rig if you aligned your midrange drivers vertically ; }
Click to expand...

BTW ,greenboy, even if vertically aligned, you still suffer the time delay between drivers, thus, unclarity. the reason the pro p.a.linesource is supposed to sound good is that the vertical dispersion is so narrow, they are bassically aligned so you only hear one box, the one pointed at you. yet the low end is additive from all the boxes. yo cannot get better than a point source, so at the least get one driver to produce each range instead of multiples, at least one tweeter /midrange. johnnny a
 
#9
speaking of xovers, with eighteen" cabs and 8x10 cabs, even an 18 db crossover , the lows still suffer from the tens operating at the same time. even when crossed at 200-250hz. you listen to the eighteens, and then u add the tens and hear the lows dissapear. i mean the lows. 20-40 hz. ive tried the tens and eighteens all ways, different slopes, this one x-ed over, this one not, i finally gave up and ran the eighteens full range and the jbl horn 6db slope at 1k, best rig i ever heard. last time i was at ampeg, i almost mentioned maybe making/marketing a hi-fi bass cab, i bit my tounge. it would be soooo expensive and big . johnny a
 
#10
staindbass said:
it would be soooo expensive and big
Click to expand...
Neither expensive nor big. In a well designed cab 1x15 or 2x12 provides all the bottom one needs, while two 5s or 8s give better mids than any 4x10. Tweeter: optional. Covering the upper end with a couple of small midrange drivers is a lot cheaper and smaller than two to four tens, and works better too.
 
#11
Just to show how ugly things can get and why I'd never use something like an 8X10 except maybe bellow 1K

Here are some speaker array predictions. That is if these drivers acted as perfect point sources, cramed as closely together as possible with 10" spacing between centers.

8X10Polar.jpg


I suspect reality is even uglier!

Cheers!
 
#13
billfitzmaurice said:
Neither expensive nor big.
Click to expand...
It would be for Johnny. I don't think he's capable of doing small and affordable ;)

BTW, on a related subject (beaming), would a device like this Beam Blocker from Weber work? I've been toying with the idea of ordering one for my B-15 just to see if it works, and Weber seems pretty reliable from what I've heard, but I'd like a second opinion.

Invalid Link Removed
 
#14
JimmyM said:
It would be for Johnny. I don't think he's capable of doing small and affordable ;)

BTW, on a related subject (beaming), would a device like this Beam Blocker from Weber work? I've been toying with the idea of ordering one for my B-15 just to see if it works, and Weber seems pretty reliable from what I've heard, but I'd like a second opinion.

Invalid Link Removed
Click to expand...

I can't see it working, as it does not reduce the overall width of the driver. Thinking simplistically, the polar pattern would be equal to the polar pattern of a big driver, minus that of a small driver. So it would still be a complicated lumpy polar plot.
 
#15
fdeck said:
I can't see it working, as it does not reduce the overall width of the driver. Thinking simplistically, the polar pattern would be equal to the polar pattern of a big driver, minus that of a small driver. So it would still be a complicated lumpy polar plot.
Click to expand...

If the beam blocker were of sufficient geometry and materials to disperse the on-axis peaky stuff coming off the dust cap slightly, to make a wider polar, I suppose it would be considered of benefit by some. No free lunch there, though - some might miss that narrow on-axis spike and it would seem to be as uneven in effect as a lot of poorly-designed HF horns ; }
 
#20
JimmyM said:
It would be for Johnny. I don't think he's capable of doing small and affordable ;)

BTW, on a related subject (beaming), would a device like this Beam Blocker from Weber work? I've been toying with the idea of ordering one for my B-15 just to see if it works, and Weber seems pretty reliable from what I've heard, but I'd like a second opinion.

Invalid Link Removed
Click to expand...

I have used and heard the Beam Blocker many times. They make a huge difference for guitar. As a member of the audience, I have never felt that I was getting drilled by a bass cab like I do from guitar. If anybody wants to try one, it is very easy to make your own. Do you have tape?
 

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